Herring arrives earlier in the Wadden Sea due to climate change

Due to the changing climate, young herring arrive in the Wadden Sea earlier and earlier in spring. That is shown in a new publication by NIOZ ecologists Mark Rademaker, Myron Peck and Anieke van Leeuwen, in this month's journal Global Change Biology. "The fact that we were able to demonstrate this, was only due to very consistently, for more than 60 years, and continuously sampling the fish every spring and every fall with exactly the same fyke every time," Rademaker says. "Recognizing this kind of change requires extreme precision and endurance!"

NIOZ fyke

Since 1960, NIOZ, Royal Netherlands Institute for Sea Research, has been measuring the number and species of fish that swim in the Marsdiep, between Den Helder and Texel, day in and day out using a standard fyke, in spring and fall. These measurements show that the peak of the number of young herring swimming into the Wadden Sea since 1982 comes at least two weeks earlier now. "Such a calculation is difficult with a species of fish that swims in large schools," Rademaker says. "One day there may be only ten herring, while the next there are suddenly ten thousand fish swimming by. So, if you were to accidentally take a measurement just one day or the other, you would get a completely different picture."

Extremely consistent measurement

According to Rademaker, the solution to that problem lies in extremely consistent measurement, almost to the square meter. "Only by carrying out measurements in the same place over and over again, and almost continuously, year after year, can you reliably reveal changes in the long term."

Unique set of data

The research with the 'NIOZ fyke' is unique in the world. Most other monitoring programs measure only once or a few times per month or even per quarter, and then often not even at exactly the same spot. Rademaker: "When I projected that frequency from other research programs onto the data from the NIOZ fyke, picking out a few random measurement days, the changes in the timing of the herring did not show up."

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New approach needed to save Australia's non-perennial rivers

Non-perennial rivers, which stop flowing at some point each year, dominate surface water movement across Australia, yet monitoring the continued health of these vital waterways demands a new type of research attention.

More than 70% of this nation's rivers are non-perennial due to a combination of ancient landscape, dry climates, highly variable rainfall regimes, and human interventions that have altered riverine environments.

An extensive review of current research incorporating geomorphology, hydrology, biogeochemistry, ecology and Indigenous knowledges identifies prevailing factors that shape water and energy flows in Australia's non-perennial rivers -- but the review also points to research deficiencies that must be addressed if these river systems are to be preserved and protected.

"Australia relies on our rivers, and has a strong history of research to understand river flows and ecosystems and the human impacts on them. Now, we must address emerging threats to river systems due to climate change and other anthropogenic impacts," says lead author of the review, Dr Margaret Shanafield, from Flinders University's College of Science and Engineering.

"We have to work together to tackle emerging threats to our rivers. If we are going to plug gaps in existing knowledge, which this review identifies, then a new style of inter-disciplinary scientific research is necessary to achieve the required outcomes."

While dominant research themes in Australia focus on drought, floods, salinity, dryland ecology and water management, four other areas of research attention are urgently needed, namely:

•     Integrating Indigenous and western scientific knowledge;
•     Quantifying climate change impacts on hydrological and biological function;
•     Clarifying the meaning and measurement of "restoration" of non-perennial systems;
•     Understanding the role of groundwater.

Addressing these areas through multi-disciplinary efforts supported by technological advances will provide a map for improved water research outcomes that the rest of the world can follow.

"Australia is globally unique in its spread and diversity of non-perennial rivers spanning climates and landforms -- but most, if not all, of the classes of non-perennial rivers found in Australia also occur in other regions of the world with similar climates and geology," says Dr Shanafield.

"Therefore, the evolving body of knowledge about Australian rivers provides a foundation for comparison with other dryland areas globally where recognition of the importance of non-perennial rivers is expanding."

The review authors are concerned that Australian non-perennial river research has been driven by the needs of its inhabitants for survival, agriculture, resource economics, environmental concern and politics.

"Considering the continent's ancient geological history and its harsh, arid climate, it comes as no surprise that significant attention has been directed toward water resource management during drought periods, the reduction of salinisation, and gaining insights into the intricate dynamics of the transient rivers that are a defining feature of central Australia," says the review.

"The prevalence of prolonged drought periods has had a marked impact on driving research -- so it is critical to address the knowledge gaps this review has identified, given that increasing trends in hydrological droughts are projected to negatively impact streamflow not just in Australia, but also in South America, southern Africa, and the Mediterranean."

The review authors -- a multi-disciplinary collective of scientists from across more than two dozen institutions and government departments -- say more investment in long-term hydrological monitoring is desperately needed to increase water management knowledge that can address the competing water needs of communities, agriculture, mining and ecosystems in a dry environment -- not only in Australia, but throughout the world.

"We anticipate that changing global water fluxes and continued groundwater pumping will cause more of the world's rivers to become non-perennial, accelerating our need to understand these systems across many disciplines," says Dr Shanafield.

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Invasive plant time bombs: A hidden ecological threat

Invasive plants can stay dormant for decades or even centuries after they have been introduced into an environment before rapidly expanding and wreaking ecological havoc, according to a new study led by the University of California, Davis.

The research, published in Nature Ecology and Evolution, looked at more than 5,700 species of invasive plants in nine regions around the globe. It represents the most comprehensive analysis of plant invasions conducted to date, said senior author Mohsen Mesgaran, an assistant professor in the Department of Plant Sciences at UC Davis.

"The longer it is dormant, we're more likely to ignore it," Mesgaran said. "This latency allows them to be overlooked, contributing to their eventual emergence as a serious invasive threat. They're like invasive time bombs."

Long periods of dormancy

The international team found that nearly one-third of the invasive plants they analyzed exhibited lag periods between introduction and rapid expansion, with the average time being 40 years. The longest dormant period -- sycamore maples in the United Kingdom -- was 320 years.

Consider the common lawn weed Plantago lanceolata, otherwise known as ribwort or buckhorn plantain, which has the longest dormancy in the United States, according to the report. Noxious to livestock and native plants, the plant was introduced in the United States in 1822 and is found widely here. Velvetleaf, which was introduced as a possible fiber crop, can be dormant for 50 years before it expands, threatening corn, soybean and other crops as it sucks up water and nutrients.

Nonnative species are generally introduced in two ways: by accident or through intentional importation for medicinal, ornamental, agricultural and other purposes. In California, about 65% of invasive plants were knowingly introduced.

"This lag phase may have played a role," Mesgaran said. "They didn't know. With an increase in trade and transportation and tourism we're going to have more problems."

Global herbaria

The researchers generated a list of invasive plants in Australia, Great Britain, Ireland, Japan, New Zealand, Madagascar, South Africa, Japan and the United States and used herbaria records, which are digitized and accessible online, to obtain global data on the location and time of species observations.

They then looked at trends to determine whether species exhibited dormant phases and, if so, for how long. A time series analysis was applied to detect lag periods, followed by a second analysis that compared climate during dormant and expansion phases.

In some of the species that invaded different regions, dormancy periods varied by location. In 90% of cases, climate conditions were different during times when the species spread, suggesting the plants waited for the right conditions or adapted to survive to an environment that was once unsuitable, Mesgaran said.

Planning for the future

Knowing that problems could loom in the future is key to managing pests and preventing widespread invasion and economic losses down the road. That means growers, policymakers and others should consider dormancy periods.

"The problem is most of the models that we have for risk assessment to see if the species are going to be invasive and a pest problem in the future don't account for this lag phase or this dormant phase," Mesgaran said. "It's not that they're not going to be a problem, it's just the calm before the storm."

The next steps in the research will be to examine the native climate of invasive species relative to conditions in these newer locations.

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Spy-satellite images offer insights into historical ecosystem changes

A large number of historical spy-satellite photographs from the Cold War Era were declassified decades ago. This valuable remote sensing data has been utilised by scientists across a wide range of disciplines from archaeology to civil engineering. However, its use in ecology and conservation remains limited. A new study led by Dr. Catalina Munteanu from the Faculty of Environment and Natural Resources at the University of Freiburg, Germany, aims to advance the application of declassified satellite data in the fields of ecology and conservation. Leveraging recent progress in image processing and analysis, these globally available black-and-white images can offer better insights into the historical changes of ecosystems, species populations or changes in human influences on the environment dating back to the 1960s, the researchers suggest.

Historical satellite images cover nearly the entire globe across all seasons

In their study, the researchers initially evaluated the spatial, temporal, and seasonal coverage of over one million declassified images from four historical US spy-satellite programmes, showing that this data spans nearly the entire globe and is available across all seasons.

Upon reviewing how spy-satellite imagery is currently employed in ecology-related fields, the team then identified potential future applications.

Crucially, the broad spatial-temporal scale of the satellite images could enhance the understanding of ecological concepts such as shifting baselines, lag effects, and legacy effects.

This improved understanding could lead to better mapping of the historical extent and structure of ecosystems, aid in the reconstruction of past habitats and species distributions as well as offer new insights into historical human impacts on present ecosystem conditions.

Going forward, this knowledge can also be helpful for conservation planning and ecosystem restoration efforts by helping identify, for example, meaningful ecological baselines, the researchers explain.

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New video camera system captures the colored world that animals see, in motion

A new camera system allows ecologists and filmmakers to produce videos that accurately replicate the colors that different animals see in natural settings, Vera Vasas at the University of Sussex, UK, and colleagues from the Hanley Color Lab at George Mason University, US, report in the open access journal PLOS Biology, publishing January 23rd.

Different animals perceive the world differently because of the capabilities of the photoreceptors in their eyes.

For example, animals like honeybees and some birds can see UV light, which are outside the range of human perception.

Reconstructing the colors that animals actually see can help scientists better understand how they communicate and navigate the world around them.

False color images give us a glimpse into this dynamic world, but traditional methods such as spectrophotometry are often time consuming, require specific lighting conditions, and cannot capture moving images.

To address these limitations, researchers developed a novel camera and software system that captures animal-view videos of moving objects under natural lighting conditions.

The camera simultaneously records video in four color channels: blue, green, red and UV. This data can be processed into "perceptual units" to produce an accurate video of how those colors are perceived by animals, based on existing knowledge of the photoreceptors in their eyes.

The team tested the system against a traditional method that uses spectrophotometry and found that the new system predicted perceived colors with an accuracy of over 92%.

This novel camera system will open new avenues of research for scientists, and allow filmmakers to produce dynamic, accurate depictions of how animals see the world around them, the authors say.

The system is built from commercially available cameras, housed in a modular, 3D-printed casing, and the software is available open-source, allowing other researchers to use and build on the technology in the future.

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Raining cats and dogs: Global precipitation patterns a driver for animal diversity

Since the HMS Beagle arrived in the Galapagos with Charles Darwin to meet a fateful family of finches, ecologists have struggled to understand a particularly perplexing question: Why is there a ridiculous abundance of species some places on earth and a scarcity in others? What factors, exactly, drive animal diversity?

With access to a mammoth set of global-scale climate data and a novel strategy, a team from the Department of Watershed Sciences in Quinney College of Natural Resources and the Ecology Center identified several factors to help answer this fundamental ecological question. They discovered that what an animal eats (and how that interacts with climate) shapes Earth's diversity.

The work was recently published in the high-impact journal Ecology Letters.

"Historically studies looking at the distribution of species across Earth's latitudinal gradient have overlooked the role of trophic ecology -- how what animals eat impacts where they are found," said Trisha Atwood, author on the study from the Department of Watershed Sciences and the Ecology Center. "This new work shows that predators, omnivores and herbivores are not randomly scattered across the globe. There are patterns to where we find these groups of animals."

Certain locations have an unexpected abundance of meat-eating predators -- parts of Africa, Europe and Greenland. Herbivores are common in cooler areas, and omnivores tend to be more dominant in warm places. Two key factors emerged as crucial in shaping these patterns: precipitation and plant growth.

Precipitation patterns across time play a big role in determining where different groups of mammals thrive, Atwood said. Geographical areas where precipitation varies by season, without being too extreme, had the highest levels of mammal diversity.

"Keep in mind that we aren't talking about the total amount of rain," said Jaron Adkins, lead author on the research. "If you imagine ecosystems around the world on a scale of precipitation and season, certain places in Utah and the Amazon rainforest fall on one end with low variability -- they have steady levels of precipitation throughout the year. Other regions, like southern California, have really high variability, getting about 75 percent of the annual precipitation between December and March."

But the sweet spot for predators and herbivores fell in a middle zone between the two extremes, he said. Places like Madagascar, where precipitation patterns had an equal split between a wet season and a dry one (six months each), had the ideal ecological cocktail for promoting conditions for these two groups. Omnivore diversity tends to thrive in places with very stable climates.

The second important factor connected with mammal diversity the work uncovered was a measure of the amount of plant growth in an area, measured as "gross primary productivity."

"It makes intuitive sense for plant-eating animals to benefit from plant growth," Adkins said.

But this measure actually impacted carnivores most, according to the research. The strong relationship between predators and plant growth highlights the importance of an abundance of plants on an entire food chain's structural integrity.

"It was surprising that this factor was more important for predators than omnivores and herbivores," Atwood said. "Why this is remains a mystery."

Although evolutionary processes are ultimately responsible for spurring differences in species, climate conditions can impact related factors -- rates of evolutionary change, extinction and animal dispersal -- influencing species and trait-based richness, according to the research.

Animal diversity is rapidly declining in many ecosystems around the world through habitat loss and climate change. This has negative consequences for ecosystems. Forecasting how climate change will disrupt animal systems going forward is extremely important, Atwood said, and this research is a first step in better managing future conditions for animals around the world.

"Animal diversity can act as an alarm system for the stability of ecosystems," Atwood said. "Identifying the ecological mechanisms that help drive richness patterns provides insight for better managing and predicting how diversity could change under future climates."

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Natural GM crops: Grasses take evolutionary shortcut by borrowing genes from their neighbors

Grass may transfer genes from their neighbours in the same way genetically modified crops are made, a new study has revealed.

Research, led by the University of Sheffield, is the first to show the frequency at which grasses incorporate DNA from other species into their genomes through a process known as lateral gene transfer.

The stolen genetic secrets give them an evolutionary advantage by allowing them to grow faster, bigger or stronger and adapt to new environments quicker.

Understanding the rate is important to know the potential impact it can have on a plant's evolution and how it adapts to the environment.

Grasses are the most ecologically and economically important group of plants, covering 30% of the earth's terrestrial surface and producing a majority of our food.

The Sheffield team sequenced multiple genomes of a species of tropical grass and determined at different time points in its evolution how many genes were acquired -- giving a rate of accumulation.

It is now thought these transfers are likely to occur in the same way that some genetically modified crops are made.

These findings, published in the journal New Phytologist could inform future work to harness the process to improve crop productivity and make more resilient crops, and have implications on how we view and use controversial GM crops.

Dr. Luke Dunning, Research Fellow from the University of Sheffield's School of Biosciences, and senior author of the research, said: "There are many methods to make GM crops, some which require substantial human intervention and some that don't. Some of these methods that require minimal human intervention could occur naturally and facilitate the transfers we have observed in wild grasses.

"These methods work by contaminating the reproductive process with DNA from a third individual. Our current working hypothesis, and something we plan to test in the near future, is that these same methods are responsible for the gene transfers we document in wild grasses.

"This means, in the near future, controversial genetic modification could be perceived as more of a natural process.

"Currently, these 'natural' reproductive contamination methods are not as efficient in producing GM plants as those that are used routinely, but by further understanding how lateral gene transfer occurs in the wild we may be able to increase the success of this process."

Since Darwin, much of our understanding of evolution has been based on the assumption that genetic information is passed from parents to offspring -- the rule of common descent for plant and animal evolution.

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Evolutionary imbalance explains global plant invasions

Plant species from certain geographic regions are more successful in spreading outside their native ranges than others -- but why? An international research team led by Konstanz ecologists provides answers by exploring how the ecological and evolutionary histories of plants can influence their relationships with humans and their success as invaders.

Human activities -- for example, global trade and travel -- are driving the spread of plants beyond their natural ranges and around the globe. However, not all species benefit equally from these movements; only some are able to successfully establish populations (i.e. naturalize) in new locations. Data on the global distribution of alien plants reveals that plants originating from certain geographic regions are more successful at naturalizing than others.

The evolutionary imbalance hypothesis (EIH) offers possible explanations for this phenomenon, but has not yet been verified on a global scale. An international research team led by biologist Mark van Kleunen from the University of Konstanz has now succeeded in confirming key predictions of this hypothesis using extensive global data. In their study in Nature Ecology & Evolution, the researchers also discover intriguing similarities in the origins of plants that successfully establish populations outside their natural ranges and those that humans have selected for cultivation and economic use -- suggesting that biogeographic factors influence biological and cultural systems in similar ways.

Dating back to Darwin

At its essence, the ideas of the EIH date back to Charles Darwin. "Darwin proposed that geographic barriers divide the Earth's ecosystems into various evolutionary arenas," says Trevor Fristoe, first author of the study and ecologist at the Department of Biology at the University of Konstanz. Within each of these arenas, the organisms inhabiting them would be exposed to unique geographic and ecological conditions that influence the intensity of natural selection. "The result is differences in the absolute fitness for species originating from different regions -- evolutionary imbalances -, and these differences have consequences for which species are more likely to successfully establish in new areas when barriers are removed," Fristoe continues.

Based on these ideas, the EIH makes predictions about the characteristics of global regions that drive the evolution of particularly successful aliens. For example, larger regions should support larger populations and higher genetic diversity to allow for more efficient natural selection. Species-rich regions should serve as intense proving grounds where species must evolve to persist in the presence of a wide variety of competitors and enemies.

The current study tested these predictions on a global scale. For this, the researchers used an unprecedented data set that included the native and alien distributions of over 99 percent of all known seed plants -- over 330,000 species. Consistent with the EIH, they demonstrated that plants originating from vast, species-rich regions are among the most successful alien plants. "Thus, our study confirms two key predictions of the EIH on a global scale," emphasizes Mark van Kleunen, head of the international research team.

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Learning about what happens to ecology, evolution, and biodiversity in times of mass extinction

In times of environmental upheaval, how do communities of organisms respond? When entire species are wiped out, do surviving species move in and take over, or do new species immigrate to fill the gaps?

These are questions that Sarah Brisson, Ph.D. student in UConn's Department of Earth Sciences, set out to study. This research is published in the Proceedings of the Royal Society B.

Brisson studies a mass extinction event that happened in the Late Devonian period, around 370 million years ago, with the goal of understanding how ecosystems and the communities of organisms within them respond. For this study, Brisson focused on small, shelled, ocean-dwelling creatures called brachiopods by studying fossils collected from the Appalachian Basin in New York and Pennsylvania.

"The name 'mass extinction events' captures people's attention. These are times of major changes in the environment, and how those changes impact the organisms is relevant to understanding our current environment and environmental changes," says Brisson.

In the Late Devonian, the Appalachian Basin was a shallow sea that formed in the wake of the growing mountains. Brisson says the seafloor was likely covered with brachiopods, which were abundant in the sample set. In the water, fish were also becoming more abundant, and on land, a great greening was happening, with new plants evolving for the first time in Earth's history.

"The Devonian world was very different; there were no flowering plants for millions of years. We're just setting the stage to move into the Mesozoic -- the dinosaur era -- where we have big ferns and large, woody trees," Brisson says.

In studying these ecosystem dynamics, Brisson looks at Earth as a system, with niche changes just one aspect of the entire structure.

"A niche space is an environment where an organism lives, in this case, the level of substrate disturbance and where along the depth profile the organisms most comfortable with," says Brisson.

Two concepts to consider are niche conservatism and niche evolution. Brisson explains that with niche conservatism, organisms remain in place and retain their characteristics, whereas with niche evolution organisms change and evolve in some way into preferring the new environmental parameters through time.

"In biology, there's a lot of talk about niche dynamics, and whether we see niche evolution or niche conservatism and there are not as many researchers studying this in deep time," says Brisson.

After painstakingly identifying around 20,000 brachiopod fossils and analyzing their preferences across the depth gradient, Brisson assembled a dataset and used non-metric multi-dimensional scaling (nMDS) to see where different species were grouped across the stratigraphic range over time to interpret how the organisms responded before and after the mass extinction event. Brisson says the results were a bit of a surprise.

"I saw a lot of turnover where some species went extinct, but some species survived and remained in place, and their niches are conserved. Some scientists argue this isn't the case in a large-scale extinction event and I didn't expect that niche conservatism would be shown here."

In extinction events like this one, where an estimated 35% of marine species went extinct, Brisson explains it is expected that the opening of so many niches would encourage nearby surviving species to move in to occupy the newly free space, and the results did show this happening to some extent.

"As a rule, however, we're seeing niche conservatism in this region. In cases where you might see niche evolution in the rock record, there may have been different pressures on the organisms. I think leaving that question open is important because there are many different selective pressures and not all selective pressures can be applied to every situation."

The factors that drove the extinction pulses in the Late Devonian are still debated, says Brisson. Some work, including co-author and UConn graduate Jaleigh Pier's '18 (CLAS) research, indicated a global cooling event took place. Other evidence shows widespread anoxia which could have resulted from an influx of nutrients, much like we see today with dead zones forming in offshore marine and aquatic environments.

"Part of the reason why I love the Devonian is that there are mass extinction events that have been studied so thoroughly, especially the Mesozoic mass extinction event, but there's less certainty surrounding the Late Devonian. As you're moving back through time, it's harder to be certain because some of the proxies used in the Mesozoic don't apply to the Devonian. It's a neat and dynamic time to study."

This work represents just one chapter of Brisson's dissertation, and future analyses will look at the data further, including stable isotope analysis to understand how nitrogen may have impacted this region. Peering this far into the past may shed light on the accelerating species extinctions of today.

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Increased droughts are disrupting carbon-capturing soil microbes, concerning ecologists

Soil stores more carbon than plants and the atmosphere combined, and soil microbes are largely responsible for putting it there. However, the increasing frequency and severity of drought, such as those that have been impacting California, could disrupt this delicate ecosystem. In a perspective publishing in the journal Trends in Microbiology on April 12, microbial ecologist Steven Allison warns that soil health and future greenhouse gas levels could be impacted if soil microbes adapt to drought faster than plants do. He argues that we need to better understand how microbes respond to drought so that we can manage the situation in both agricultural and natural settings.

"Soil microbes are beneficial, and we couldn't live without their cycling of carbon and nutrients, but climate change and drought can tweak that balance, and we have to be aware of how it's changing," says Allison of the University of California, Irvine.

Some soil microbes take carbon from decomposing plants and store it in the soil, while others release plant carbon back into the atmosphere. The carbon that ends up in the soil is beneficial in multiple ways. "The carbon in the soil has these reverberating effects out to the rest of the world in terms of the infrastructure in our natural and managed ecosystems," says Allison. "Carbon-rich soils hold more nutrients, so plants growing in those soils tend to be more productive, and the carbon changes the physical properties of the soil, which prevents erosion."

"In California now, we have this system where the droughts are more intense, and then the rainfall is more intense," he says. "So, if you're losing your soil carbon, when it rains really hard it could carry away your soil and cause erosion, landslides, mudslides, sediments, and all kinds of problems that we're actually seeing right now."

The carbon that is released back into the atmosphere is another story. "From a climate mitigation standpoint, what we want is for more carbon to be in plants and soils and less carbon to be in the atmosphere, so the more carbon we can absorb into plants through photosynthesis and the more we can transfer and keep in the soil, the better off we're going to be in terms of climate change," says Allison. "That's why it's really important to know how the balance of incoming versus outflowing carbon changes with drought, or warming, or any other climate factor."

Plants and microbes will both be impacted by the increasing frequency of drought, but Allison suspects that microbes will be able to bounce back faster. "Microbes are really adaptable -- they can change their physiology, they can change their abundances so that more drought-adapted microbes take over, and they can potentially evolve -- so we expect that they are going to resist or bounce back from drought," says Allison. "All those different processes can happen pretty quickly with microbes, and much more quickly than with plants."

If more carbon-releasing microbes survive than carbon-sequestering microbes, we could end up with carbon-depleted soils, which would have serious negative implications for plant productivity and future greenhouse gas levels.

We may be able to nudge the balance in the right direction, Allison says, but more research is needed first. "There's still a lot to be done. Right now, we have data that suggests that when we have drought, something changes that results in carbon loss, but we don't understand exactly how or why that's happening, whether drought's changing the abundance of beneficial plant associated microbes versus the carbon releasing microbes, or if it's causing the evolution of one of the microbe groups, or if it's more determined by changes to their immediate physiology," says Allison.

Some microbes could actually help plants cope with drought. If we knew which microbes were most beneficial to plants, and most likely to retain carbon in soil, we could try to tip the balance in their favor.

"There's a lot of potential for us to manage or engineer soil microbes," says Allison. "In agricultural systems, we can look into manipulating the soil or adding beneficial microbes back in. In more natural systems, management would probably be on the plant side: soil microbes are often closely intertwined with plants, so managing the plants can also benefit the microbial part of the ecosystem."

Read more at Science Daily

Ecology: More than the sum of its parts

Global warming, as a component of climate change, is probably one of the best-known risks to the ecological balance of ecosystems and global biodiversity. However, ecosystems worldwide are also exposed to many other human-induced global change factors (GCFs) -- with the number and intensity of simultaneously acting factors increasing. Examples include phenomena such as light pollution, i.e. the brightening of the night sky caused by artificial light sources, or the accumulation of pesticides, such as fungicides, in the environment.

"We have a pretty clear picture of how some of these factors individually can affect parts of an ecosystem, such as a plant community. In fact, their individual impacts on a community can be quite different and even opposite," explains Benedikt Speißer, first author of the recent study and doctoral student in the laboratory of Mark van Kleunen in the Department of Biology at the University of Konstanz. What happens when an ecosystem is exposed to several of these factors simultaneously has been less well studied, although this is likely the case in most natural ecosystems.

Experiments under controlled conditions

To address this lack of knowledge, the ecologists led by Mark van Kleunen investigated how simultaneously acting GCFs affect the composition and productivity of plant communities and what role the sheer number of factors plays in this. For this purpose, they created small artificial ecological communities -- generally known as mesocosms -- consisting of nine different grasses and forbs native to Central Europe, where the selected species are widespread and often co-occur. Under controlled conditions, the researchers subsequently exposed these mesocosms to different numbers -- 0, 1, 2, 4, or 6 -- of GCFs for a duration of several weeks.

"For our experiments, we selected GCFs that do indeed often act simultaneously on an ecosystem, but differ greatly in their respective chemical and physical natures," explains van Kleunen. Besides the GCFs already mentioned -- climate warming, light pollution and fungicide accumulation -- microplastic pollution, eutrophication, which is the accumulation of nutrients in an ecosystem, and soil salinization were additional factors studied.

Quantity not quality

The researchers found that as the number of GCFs acting simultaneously increases, so does biomass production in the plant communities. "The more GCFs, the higher the probability to include a highly influential factor, such as eutrophication. In these cases, one could expect higher productivity due to the high availability of nutrients," Speißer explains. However, the researchers' analyses showed that interactions between other factors can also contribute to this effect.

Read more at Science Daily

Old-growth trees more drought tolerant than younger ones, providing a buffer against climate change

A new analysis of more than 20,000 trees on five continents shows that old-growth trees are more drought tolerant than younger trees in the forest canopy and may be better able to withstand future climate extremes.

The findings highlight the importance of preserving the world's remaining old-growth forests, which are biodiversity strongholds that store vast amounts of planet-warming carbon, according to University of Michigan forest ecologist Tsun Fung (Tom) Au, a postdoctoral fellow at the Institute for Global Change Biology.

"The number of old-growth forests on the planet is declining, while drought is predicted to be more frequent and more intense in the future," said Au, lead author of the study published online Dec. 1 in the journal Nature Climate Change.

"Given their high resistance to drought and their exceptional carbon storage capacity, conservation of older trees in the upper canopy should be the top priority from a climate mitigation perspective."

The researchers also found that younger trees in the upper canopy -- if they manage to survive drought -- showed greater resilience, defined as the ability to return to pre-drought growth rates.

While deforestation, selective logging and other threats have led to the global decline of old-growth forests, subsequent reforestation -- either through natural succession or through tree planting -- has led to forests dominated by increasingly younger trees.

For example, the area covered by younger trees (<140 years old) in the upper canopy layer of temperate forests worldwide already far exceeds the area covered by older trees. As forest demographics continue to shift, younger trees are expected to play an increasingly important role in carbon sequestration and ecosystem functioning.

"Our findings -- that older trees in the upper canopy are more drought tolerant, while younger trees in the upper canopy are more drought resilient -- have important implications for future carbon storage in forests," Au said.

"These results imply that in the short term, drought's impact on forests may be severe due to the prevalence of younger trees and their greater sensitivity to drought. But in the long run, those younger trees have a greater ability to recover from drought, which could be beneficial to the carbon stock."

Those implications will require further study, according to Au and colleagues, given that reforestation has been identified by the Intergovernmental Panel on Climate Change as a potential nature-based solution to help mitigate climate change.

The Sharm el-Sheikh Implementation Plan published during the 2022 United Nations Climate Change Conference in Egypt (COP27) also reaffirmed the importance of maintaining intact forest cover and associated carbon storage as a social and environmental safeguard.

"These findings have implications for how we manage our forests. Historically, we have managed forests to promote tree species that have the best wood quality," said Indiana University's Justin Maxwell, a senior author of the study.

"Our findings suggest that managing forests for their ability to store carbon and to be resilient to drought could be an important tool in responding to climate change, and thinking about the age of the forest is an important aspect of how the forest will respond to drought."

The researchers used long-term tree-ring data from the International Tree-Ring Data Bank to analyze the growth response of 21,964 trees from 119 drought-sensitive species, during and after droughts of the past century.

They focused on trees in the uppermost canopy. The forest canopy is a multilayered, structurally complex and ecologically important zone formed by mature, overlapping tree crowns.

The upper canopy trees were separated into three age groups -- young, intermediate and old -- and the researchers examined how age influenced drought response for different species of hardwoods and conifers.

They found that young hardwoods in the upper canopy experienced a 28% growth reduction during drought, compared to a 21% growth reduction for old hardwoods. The 7% difference between young and old hardwoods grew to 17% during extreme drought.

While those age-related differences may appear fairly minor, when applied at the global scale they could have "huge impacts" on regional carbon storage and the global carbon budget, according to the study authors. That's especially true in temperate forests that are among the largest carbon sinks worldwide.

In the study, age-related drought-response differences in conifers were smaller than in hardwoods, likely because needle-bearing trees tend to inhabit more arid environments, the researchers say.

The current study was part of Au's doctoral dissertation at Indiana University, and he continued the work after joining U-M's Institute for Global Change Biology, which is based at the School for Environment and Sustainability.

The new study is a synthesis that represents the net effects of thousands of trees in diverse forests across five continents, rather than focusing on single forest types. In addition, the new study is unique in its focus on trees in the upper forest canopy, which reduces the confounding effects of tree height and size, according to the authors.

Read more at Science Daily

Planet's rarest birds at higher risk of extinction

A new study finds that bird species with extreme or uncommon combinations of traits face the highest risk of extinction. The findings are published in the British Ecological Society journal Functional Ecology.

A new study led by researchers at Imperial College London finds that the most unique birds on the planet are also the most threatened. Losing these species and the unique roles they play in the environment, such as seed dispersal, pollination and predation, could have severe consequences to the functioning of ecosystems.

The study analysed the extinction risk and physical attributes (such as beak shape and wing length) of 99% of all living bird species, making it the most comprehensive study of its kind to date.

The researchers found that in simulated scenarios in which all threatened and near-threatened bird species became extinct, there would be a significantly greater reduction in the physical (or morphological) diversity among birds than in scenarios where extinctions were random.

Bird species that are both morphologically unique and threatened include the Christmas Frigatebird (Fregata andrewsi), which nests only on Christmas Island, and the Bristle-thighed Curlew (Numenius tahitiensis), which migrates from its breeding grounds in Alaska to South Pacific islands every year.

Jarome Ali, a PhD candidate at Princeton University who completed the research at Imperial College London and was the lead author of the research, said: "Our study shows that extinctions will most likely prune a large proportion of unique species from the avian tree. Losing these unique species will mean a loss of the specialised roles that they play in ecosystems.

"If we do not take action to protect threatened species and avert extinctions, the functioning of ecosystems will be dramatically disrupted."

In the study, the authors used a dataset of measurements collected from living birds and museum specimens, totalling 9943 bird species. The measurements included physical traits like beak size and shape, and the length of wings, tails and legs.

The authors combined the morphological data with extinction risk, based on each species' current threat status on the IUCN Red List. They then ran simulations on what would happen if the most threatened birds were to go extinct.

Although the dataset used in the study was able to show that the most unique birds were also classified as threatened on the Red List, it was unable to show what links uniqueness in birds to extinction risk.

Read more at Science Daily

Getting data to do more for biodiversity

Michigan State University ecologists have developed a mathematical framework that could help monitor and preserve biodiversity without breaking the bank.

This framework or model takes low-cost data about relatively abundant species in a community and uses it to generate valuable insights on their harder-to-find neighbors. The journal Conservation Biology published the research as an Early View article on Aug. 25.

"One of the biggest challenges in monitoring biodiversity is that the species you're most concerned about tend to be lowest in abundance or they're the hardest species to observe during data collection," said Matthew Farr, the lead author on the new report. "This model can be really helpful for those rare and elusive species."

Farr, now a postdoctoral researcher at the University of Washington, helped develop the model as a doctoral student in Elise Zipkin's Quantitative Ecology Lab in the College of Natural Science at MSU.

"There are a lot of species in the world and many of them are data deficient," said Zipkin, an associate professor of integrative biology and director of MSU's Ecology, Evolution and Behavior Program, or EEB. "We're developing approaches to more quickly estimate what's going on with biodiversity, which species are in trouble and where, spatially, do we need to focus our conservation efforts."

After validating the model with an assist from forest-dwelling antelope in Africa, the researchers say it could be applied to a variety of other animals that meet certain criteria.

"The model doesn't work for all types of species. It's not a panacea," Zipkin said. "But when it does work for a community, we can learn a lot more about member species without much data."

The 'magic' of the model

For its newest model, Zipkin's team focused on what's called detection-nondetection data that tracks whether or not a given animal is detected in a given habitat.

"It's basically the cheapest data and the easiest to collect," Zipkin said. "You go to a spot, wait and see what animals are there and only need to record which species are seen."

Researchers gather this data visually in person or with low-cost, motion-detecting camera traps that snap photos when triggered by an animal. Researchers then analyze the photos to record detection-nondetection data over time.

There are trade-offs, though. Although relatively cheap and easy to collect, detection-nondetection data doesn't provide as much information as researchers and conservationists want. Historically, that has required intensive observational approaches such as tagging and tracking animals.

"That lets us calculate all sorts of things about the animals and their communities, but that data is expensive and hard to get," Zipkin said. "For certain species, it's impossible."

The MSU team realized that, for the right animals, they could use an understanding of animal behavior and statistics to close the information gap by squeezing more insight out of detection-nondetection data.

"For some species, these are the best data you can get," Farr said. "Now we can get more out of it."

That may sound like magic -- some of Zipkin's colleagues have even said so -- ?but there's nothing supernatural about the model. Like much of science, it's the result of hard work, collaboration and building on previous efforts in the field.

The story of the new model has its roots in 2003 with researchers J. Andrew Royle and James D. Nichols. The duo devised a mathematical link between the abundance of a species and the probability of detecting it.

At the time, Royle was a researcher with the U.S. Fish and Wildlife Service and Nichols was with the U.S. Geological Survey. Both are MSU alumni: Royle graduated with his bachelor's degree in 1990 and Nichols earned his doctorate in 1976.

"It's interesting," said Farr, whose current adviser, Sarah Converse, also graduated with a bachelor's degree from Michigan State before becoming an associate professor at the University of Washington. "Wherever you go in this field, people have some connection to Michigan State."

After publishing the Royle-Nichols model, Royle joined the USGS, where he'd work with Zipkin before she joined MSU in 2014. In 2016, Zipkin's team evolved the Royle-Nichols model to estimate things like the survival and reproduction rates for a single species using the barred owl as a case study.

Working in Zipkin's lab with support from the National Science Foundation, Farr took the next step by linking the population dynamics of different species within the same communities.

"The model lets information from more common species inform what's happening with the rare and elusive species," said Farr. "The model relies on the commonalities between species, but still allows for variations."

To develop the model, the team had to make some assumptions, like that the target species were territorial and did not travel much. The researchers then had to find real species that fit those assumptions to validate their model.

"We knew it would work for certain types of communities, but did those communities exist in real life?" Zipkin said.

"That's one of the biggest challenges in model development," Farr said. "You develop the model in a vacuum with simulations running under perfect conditions. You need to show what it can do in a real-world situation."

"That's when Tim O'Brien reached out and said, 'I have your animals,'" Zipkin said.

The duiker data

Timothy O'Brien is a retired ecologist in Kenya who worked with the Wildlife Conservation Society, a nongovernmental organization or NGO, and an expert in camera traps. As part of what's known as the Tropical Ecology Assessment and Monitoring program, or TEAM, he's helped standardize how camera traps are used to make their data as powerful as possible.

He was familiar with Zipkin's 2016 work and learned that she was expanding the model to include multiple species over multiple seasons. He suspected that forest-dwelling antelopes, notably those known as duiker, would provide the perfect test case.

Not only did duiker behavior match the assumptions of the model, but O'Brien had been helping monitor the animals for years using camera traps. Duikers presented an interesting and important conservation case.

"The duiker that live in rainforests, they are the most sought-after bushmeat in Africa," O'Brien said. "If duiker populations are in decline, it's usually because of people hunting for bushmeat."

Bushmeat is meat from any wild animal and it's an important source of food and income for many communities. But the hunting is loosely regulated and is financially incentivized by markets that sell bushmeat. The combination can be devastating for duiker populations.

With MSU's model and TEAM's duiker data, the team assessed the population dynamics of a total of 12 antelope species -- some more abundant than others -- in six national parks in Africa, where duikers are protected. The data covered time periods ranging from four to 11 years.

"We didn't see the level of population decline in duiker you expect to see when hunting is an issue," O'Brien said. "I would say the parks are fulfilling their function as far as duiker are concerned."

Overall, the duiker populations were mostly stable, but the researchers did detect population declines in about 20% of the combinations of species and parks that they examined. Again, the declines weren't so substantial to suggest that the duiker were being overhunted in the parks, but the researchers still want to understand what's happening in those cases.

"We found that's what causing the changes was more the differences between the parks than between the species," Zipkin said. "We haven't pinpointed the exact causes yet, but our results could help us do that."

"Matt and Elise have taken this model to a whole new plane," O'Brien said. "I've really enjoyed the collaboration."

Read more at Science Daily

Delicate balance of coral reef processes creates management challenges

An international team of researchers, including several from the University of Hawai'i (UH) at M?noa, has quantified five critical ecological processes on more than 500 coral reefs worldwide to understand how these processes relate to each other, what may distinguish the most functional reefs, and what that means for our management of reef functioning.

Their work, published today in Nature Ecology and Evolution, demonstrates that five key functions performed by fish communities-the removal of algae, predation, biomass production, and the cycling of nitrogen and phosphorus- are inherently interconnected. As such, while the performance of these processes is influenced by the community structure of reef fishes on any given reef, no reef can maximize each of the five processes simultaneously.

Coral reefs are often described as the rainforests of the ocean. They host a high diversity of species and are very productive. Climate change and local threats, such as overfishing, have caused a stark decline in coral reefs worldwide, leaving scientists questioning whether future generations will still encounter healthy, 'functional' coral reefs. But what exactly makes a coral reef 'functional'?

"Imagine a coral reef fish community swirling with small fishes that feed on algae," explained Nina Schiettekatte, the lead author, former doctoral student at the Center for Island Research and Environmental Observatory and postdoctoral fellow at UH M?noa's Hawai'i Institute of Marine Biology (HIMB). "This community will be characterized by high algal consumption and high biomass production, but it will have low phosphorus cycling because these species excrete very little phosphorus."

This means that ecological processes on coral reefs worldwide are in a delicate balance, where it is impossible to maximize all processes. The researchers gained this knowledge by collecting data from individual fishes and combining it with a large dataset on fish communities worldwide.

A detailed look reveals local super heroes

"Throughout this project, we collected thousands of fishes across more than 100 species to gain detailed biological information on how they acquire and use energy and nutrients," explained Jordan Casey, an Assistant Professor at the University of Texas at Austin.

This information can then be projected onto communities to understand how fish communities collectively move biomass and nutrients through the foodweb.

"Our work is novel because it quantifies multiple functions for the first time," Valeriano Parravicini, Professor at EPHE in Perpignan, France stated. "Previously, most researchers have used the biomass of a fish community as a proxy for coral reef functioning but we show that it is critical to look beyond biomass and really disentangle the different components of functioning to understand how reefs work."

Knowing that no reef can excel in all functions, the researchers asked whether there is a certain set of species that is more important than others. Surprisingly, they found that no single species was consistently important across its range, but half of all species were important in at least one location.

"This means that there are no global super-hero fish species for ecosystem functioning," said Sébastien Villéger, researcher at the CNRS in Montpellier, France. "But there are many local super heroes."

A more nuanced management approach

"This work really changes the way we need to think about coral reef conservation," Simon Brandl, an Assistant Professor at the University of Texas at Austin concluded. "Since we cannot maximize all aspects of functioning, we clearly need to develop a more nuanced approach to conserving coral reefs that considers local species, ecosystem dynamics, and stakeholder needs."

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European earthworms reduce insect populations in North American forests

Earthworms introduced into northern North America have a negative impact on the insect fauna above ground. Soil ecologists found this impact for abundance as well as for biomass and species richness of insects. Their results indicate that changes in insect communities can have causes that have previously received little attention.

At least since the last ice age, about 10,000 years ago, there have been almost no earthworms in the northern part of North America. However, over the last few centuries, they have been introduced, probably through soil and plant transport from Europe. Since then, they have been dispersed and changed the soil significantly, with far-reaching consequences for the soil ecosystem. What impact these invaders have on the world above ground has, up to now, rarely been investigated.

The study was performed in a forest near Calgary in Canada, which has areas that are either inhabited or uninhabited by earthworms. Here, the researchers used insect vacuum samplers to capture aboveground insects and compared the catches. They discovered that the abundance, biomass, and species richness of insects in areas with invasive earthworms, and those areas without them differed significantly. Where earthworm biomass was highest, the number of insect individuals was reduced by 61 per cent, insect biomass by 27 per cent and species richness by 18 per cent.

Insect above ground affected by invasive earthworms underground

"We had expected that earthworms would have an impact on aboveground insects," says lead author Dr Malte Jochum from iDiv and Leipzig University. "Even so, I was surprised at how pronounced the effects were, and that not only the abundance but also biomass and species richness were affected."

The mechanisms by which the earthworms affect the insects are, however, still not clear. "It's possible that the earthworms eat the food and reduce the habitat of those aboveground insects, such as beetles and fly larvae, which break down dead plant material," says Jochum. Since the majority of insects are herbivores, it could also be hypothesised that the observed decline in insects is due to changes in the vegetation caused by altered soil conditions. In this case, however, the researchers were unable to detect any significant alteration in the number of plant species or plant coverage. "Still, this doesn't rule out the influence of the plants," says Jochum. However, the data on species composition and other functional characteristics of the plant communities have yet to be evaluated.

The increase in predatory insect species and spiders was also striking. These seem to be benefiting from the changes.

Underestimated causes for biodiversity loss to be considered in conservation

"Up to now, only a few causes have been used to explain global changes in insect populations; mostly alterations in habitats above the ground," says senior author Prof Nico Eisenhauer from iDiv and Leipzig University. "These new results show that biodiversity loss can also have other causes which have, so far, received little attention and that these should be taken into consideration when developing management and conservation strategies for biodiversity."

Introduced earthworm species are not only found in North America but on almost every continent. However, since there had been very few earthworms in northern North America for a very long time, the effect of these invaders is particularly pronounced. "For regions like Europe, where natural communities have always co-developed with earthworms, comparable negative effects due to new earthworm species are very unlikely," says Jochum. "Quite the opposite. Here they are important ecosystem engineers, which many important ecosystem functions depend on."

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Elephants benefit from having older siblings, especially sisters

A study of semi-captive Asian elephants in Myanmar has found that calves benefit from having older sisters more than older brothers. The findings are published in the British Ecological Society's Journal of Animal Ecology.

Researchers at universities in Finland, the UK and Myanmar have found that Asian elephant siblings influence younger offspring from early through to late-life. Being raised with older siblings strongly increased calves' long-term survival compared to not having a sibling, with elder sisters having a bigger impact than elder brothers.

In female elephants, those raised with older sisters had higher long-term survival and reproduced for the first time an average of two years earlier, compared to those with older brothers. Reproducing at an earlier age is generally associated with more offspring over the course of an elephant's lifetime.

In male elephants, those raised with older sisters had lower survival but higher body weight, compared to those with older brothers. This seemingly detrimental effect may be explained by a 'live-fast, die young' strategy, where the positive early increase in body mass could lead to survival costs later in life.

Dr Vérane Berger at the University of Turku and lead author of the study said: "Our research confirms that sibling relationships shape individual lives, particularly in social species, such as the elephants, where cooperative behaviours are essential to the development, survival and reproductive potential of individuals."

The long-term consequences from sibling effects are understudied in long-lived animals. One of the reasons for this is that the logistic challenges of field studies make it hard to investigate effects over an animal's entire lifespan.

In this study, the researchers were able to overcome this barrier by studying a population of government-owned, semi-captive timber elephants in Myanmar, for which extensive life history records are kept.

These elephants are used during the day as riding, transport and draft animals. At night the elephants live unsupervised in forests and can interact and mate with both wild and tame elephants. Calves are raised by their mothers until the age of five when they are trained for work. The Myanmar Timber Enterprise (MTE) imposes regulations on the daily and annual workload of elephants.

Dr Mirkka Lahdenperä at the University of Turku and co-author of the study said: "Because the elephants live in their natural habitats, there are many similarities to wild elephants, such as natural foraging and no assistance in breeding. While there are differences -- in the wild, family groups are probably bigger -- there are more similarities than differences and we could assume that some of the associations found in our study would also hold true for wild elephants. But of course, these should be studied"

The researchers used a large, multi-generational dataset of semi-captive Asian elephants to look at the influence the presence and the sex of elder siblings on the body mass, reproduction, sex, and survival of the next calf. The records contained precise reproductive and longevity information for 2,344 calves born between 1945 and 2018.

As the study was correlational, the influence of external factors outside sibling effects, such as the quality of maternal care and elephants' workload and management, cannot be excluded.

On the next steps for this research project, Dr Berger said: "By collecting more information on the body mass of mothers at birth, we hope to disentangle maternal effects from sibling effects.

"More data will also let us explore the effects of the environment on sibling relationships and go into more detail on the effects siblings have on specific aspects of a younger calf's health, such as immunity, muscular function and hormonal variations.

Read more at Science Daily

Researchers create map of potential undiscovered life

 Less than a decade after unveiling the "Map of Life," a global database that marks the distribution of known species across the planet, Yale researchers have launched an even more ambitious and perhaps important project -- creating a map of where life has yet to be discovered.

For Walter Jetz, a professor of ecology and evolutionary biology at Yale who spearheaded the Map of Life project, the new effort is a moral imperative that can help support biodiversity discovery and preservation around the world.

"At the current pace of global environmental change, there is no doubt that many species will go extinct before we have ever learned about their existence and had the chance to consider their fate," Jetz said. "I feel such ignorance is inexcusable, and we owe it to future generations to rapidly close these knowledge gaps."

The new map of undiscovered species was published March 22 in the journal Nature Ecology & Evolution.

Lead author Mario Moura, a former Yale postdoctoral associate in Jetz's lab and now professor at Federal University of Paraiba, said the new study shifts the focus from questions like "How many undiscovered species exist?" to more applied ones such as "Where and what?"

"Known species are the 'working units' in many conservation approaches, thus unknown species are usually left out of conservation planning, management, and decision-making," Moura said. "Finding the missing pieces of the Earth's biodiversity puzzle is therefore crucial to improve biodiversity conservation worldwide."

According to conservative scientific estimates, only some 10 to 20 percent of species on earth have been formally described. In an effort to help find some of these missing species, Moura and Jetz compiled exhaustive data that included the location, geographical range, historical discovery dates, and other environmental and biological characteristics of about 32,000 known terrestrial vertebrates. Their analysis allowed them to extrapolate where and what kinds of unknown species of the four main vertebrate groups are most likely to yet be identified.

They looked at 11 key factors which allowed the team to better predict locations where undiscovered species might be located. For instance, large animals with wide geographical ranges in populated areas are more likely to have already been discovered. New discoveries of such species are likely to be rare in the future. However, smaller animals with limited ranges who live in more inaccessible regions are more likely to have avoided detection so far.

"The chances of being discovered and described early are not equal among species," Moura said. For instance, the emu, a large bird in Australia, was discovered in 1790 soon after taxonomic descriptions of species began. However, the small, elusive frog species Brachycephalus guarani wasn't discovered in Brazil until 2012, suggesting more such amphibians remain to be found.

Moura and Jetz show that the chances of new species discovery varies widely across the globe. Their analysis suggests Brazil, Indonesia, Madagascar, and Colombia hold the greatest opportunities for identifying new species overall, with a quarter of all potential discoveries. Unidentified species of amphibians and reptiles are most likely to turn up in neotropical regions and Indo-Malayan forests.

Moura and Jetz also focused on another key variable in uncovering missing species -- the number of taxonomists who are looking for them.

"We tend to discover the 'obvious' first and the 'obscure' later," Moura said. "We need more funding for taxonomists to find the remaining undiscovered species."

But the global distribution of taxonomists is greatly uneven and a map of undiscovered life can help focus new efforts, Jetz noted. That work will become increasingly important as nations worldwide gather to negotiate a new Global Biodiversity Framework under the Convention of Biological Diversity later this year and make commitments to halting biodiversity loss.

"A more even distribution of taxonomic resources can accelerate species discoveries and limit the number of 'forever unknown' extinctions," Jetz said.

With partners worldwide, Jetz and colleagues plan to expand their map of undiscovered life to plant, marine, and invertebrate species in the coming years. Such information will be help governments and science institutions grapple with where to concentrate efforts on documenting and preserving biodiversity, Jetz said.

Read more at Science Daily

How do humpback whales rest?

An international research collaboration has used an omnidirectional camera attached to humpback whale to reveal how these creatures rest underwater. These findings demonstrate how wide-angle lens cameras can be useful tools for illuminating the ecology of difficult-to-observe animals in detail.

The research group consisted of Assistant Professor Takashi Iwata of Kobe University's Graduate School of Maritime Sciences, Researcher Martin Biuw of the Norwegian Institute of Marine Research, Assistant Professor Kagari Aoki and Professor Katsufumi Sato of the Atmosphere and Ocean Research Institute, the University of Tokyo, and Professor Patrick Miller of the University of St. Andrews.

These research results were published online in Behavioural Processes on February 25, 2021.

Main Points
 

• The researchers attached an omnidirectional (360°) camera to a humpback whale and discovered that these animals rest while drifting underwater. Whales can rest either on the surface or underwater, and it is believed that they choose which of these different environments to rest in depending on the situation.
• The omnidirectional camera recorded a wide range of information on the environment surrounding the tagged whale, revealing that humpback whales rest in groups rather than on their own.
• These results have demonstrated that animal-borne omnidirectional cameras are useful for learning more about animals that are difficult to observe.

Research Background

It is difficult to observe the ecology of marine animals directly as they spend the majority of their lives underwater. However, studies on the ecology of difficult-to-observe marine animals have been recently conducted using a method called bio-logging. This method involves attaching a camera to an animal and recording environmental information related to their behavior and surroundings. Various kinds of data can be recorded and measured, and this information can be used to understand aspects such as animal behavior and diving physiology. Such data includes depth, swimming speed, acceleration (which can be used to understand the animal's posture and detailed movements), vocalizations, heart rate and GPS (Global Positioning System) location data.

Cameras in particular are a powerful tool as they enable researchers to view the individual animal's surroundings, which in turn helps them to understand the animal's behavior. However, the camera's limited field of view has been an issue with animal-borne cameras up until now. For example, research using a camera attached to a humpback whale (Megaptera novaeangliae) revealed that the whale would quickly move away from foraging sites if a competitor was present. However, the competitor was not visible due to the limited scope of the camera, therefore its presence was merely assumed. A camera with a wide-angle lens is therefore necessary to film the animal's entire surroundings.

This research focused on the humpback whale, a species of baleen whale that is found in oceans around the globe. Using bio-logging, researchers have learned more about humpback whales' foraging habits, however little is known about their resting behaviors. Foraging events can be identified from the recorded depth, swimming speed and acceleration (movement) of the whale that are characteristic signs that it is chasing prey. However, researchers have not identified the characteristic signs of resting, and it is not understood what the differences are between resting and swimming slowly. Information about an animal's resting behavior is necessary in order to understand their ecology. For example, if we consider animal behaviors in terms of their time budget, the percentage of time for other activities such as foraging decreases if their resting periods increase. Even though information about resting behaviors is essential for understanding animal ecology, hardly anything is known about baleen whales' resting habits.

This research group used an omnidirectional camera (with a 360° field-of-view on land and a 270° field-of-view underwater) and a behavioral data logger in order to illuminate the resting behavior of humpback whales.

Research Methodology and Findings

RICOH supplied the basic THETA camera module for this research, which was made pressure-resistant and waterproofed using epoxy glue by Little Leonardo Corp., leading to the development of a new type of animal-borne omnidirectional camera. A suction cup tag was made out of buoyant materials that could be attached to the whale. The tag contained an omnidirectional camera, a behavioral data logger and a radio transmitter.

The field study was conducted in January 2016, off the Tromsø coast in Norway. To tag the whale, the researchers approached it in a small vessel (5-6m) and used a 6m pole to attach the tag to the animal. The tag was designed so that it would fall off naturally after several hours and float up to the surface. The tag was then recovered by determining its location via the signal from the transmitter.

The research team were able to tag one individual, obtaining around one hour of video data and approximately eleven hours of behavioral data. From the behavioral data, the researchers discovered that the whale was inactive during the first half of the recorded period and demonstrated active behavior in the latter half.

Based on past research, it was assumed that this active movement in the latter half was foraging activity. The video data was captured during the first half of the behavioral data recording period when the whale did not move much. In this videoed period, the tagged whale's deepest dive was 11m on average and its average swimming speed (cruising speed) was 0.75m/s-1. It has been reported that humpback whales' regular swimming speed is 1.45m/s-1, however the tagged whale was moving much more slowly during this period. Whales usually move their flukes (tails) when they swim but there were no signs that the individual whale moved its fluke in the behavioral data recorded during the videoed period. In the footage, two other whales that are drifting underwater without moving their flukes are visible. It was determined that the tagged individual was also drifting underwater from its slow swimming speed, lack of fluke movement and the continued presence in the video footage of other individuals that were drifting. Seal species, sperm whales and loggerhead turtles are known to drift underwater while they are resting. Therefore, it is believed that the tagged humpback whale in this study was also resting. Previous research has reported that baleen whale species rest on the surface but this study has revealed that they also rest while drifting underwater. It is thought that whales consider factors such as marine conditions and their own physical condition when choosing from the two different resting environments: on the surface or underwater. In addition, the footage from the omnidirectional camera shows that whales rest underwater in a group rather than on their own.

Further Research

Researchers have been using animal-borne cameras as a tool to investigate the ecology of marine animals. For example, a backwards-facing camera attached to a mother seal recorded images of a pup swimming behind her. However, to ascertain the significance of these images (for example, whether or not the mother was teaching the pup how to hunt) it is necessary to use a camera with a wide field of view so that we can obtain knowledge about the surrounding environment. Still camera images of touching behaviors between whales have also been recorded; however, a wide-lens camera would aid researchers in determining the frequency at which this behavior occurs. These examples show how necessary wide-lens cameras, such as omnidirectional cameras, are for investigating the ecology of marine animals. Such cameras enable researchers to record the environment surrounding the tagged animal, enabling them to determine whether other individuals (such as competitors, collaborators, or predators) are present or not, and understand the frequency and distribution of food sources.

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Ecological interactions as a driver of evolution

 Understanding the interaction of organisms in the evolution of species is an important topic in ecology. Insects and plants, for example, are two large groups on earth that are linked by a variety of interactions. Since the mid-20th century, theories linking this diversity and specific interactions have proliferated.

The development of new technologies and new methods has made it possible to study the interaction between plants and insects in greater detail and to reveal the impact of these interactions on their respective evolution. In a new study, an international team of researchers, including botanist Prof. Stefan Wanke of TU Dresden, has established the link between ecological changes, genome-level adaptations and macroevolutionary consequences, confirming the importance of ecological interactions as drivers of evolution over long periods of time.

Butterflies belonging to the family Papilionidae are an exemplary group for this question. These butterflies specialize in the consumption of poisonous plants, with about 30% of the species feeding exclusively on plants in the family Aristolochiaceae.

Consumption of such plants gives the caterpillars of these butterflies an advantage, as they secrete the plants' toxins, which in turn make them poisonous. However, the larvae themselves do not suffer any harm from the toxin.

"We knew before we started this study that certain genes of the cytochrome P450 family in the Papillonidae are partly responsible for the adaptation to plants, especially for the detoxification of toxic compounds. However, many different genes are probably involved overall, because in addition to detoxification, this adaptation requires that the female butterfly is able to recognize its preferred plant, or also that the caterpillars can develop and survive normally in this environment" explains Prof. Wanke. Scientists had long suspected that evolutionary changes in plants must have an influence on many insect genes. From this, the international team first deduced the relationships between different Papilionidae species and reconstructed their host-plant preferences over time. This allowed them to show that Papilionidae feed on plants belonging to the family Aristolochiaceae and, in particular, the pipevine genus Aristolochia.

Based on the global distribution of these two groups of insects and plants, it was then possible to estimate the historical biogeography -- the movement in time and space -- of Papilionidae and Aristolochiaceae species. The researchers discovered that both groups originated in the Northern Hemisphere about 55 million years ago and subsequently spread throughout the world.

In the case of the Papilionidae, this migration has been accompanied by major changes in host plants since their emergence. The study of Papilionidae species confirmed that various host-plant shifts were generally associated with accelerated species diversification of the butterflies. In other words, more species emerged as a result of host plant change than when the host plant was retained.

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