Vanishing glaciers threaten alpine biodiversity

With glaciers melting at unprecedented rates due to climate change, invertebrates that live in the cold meltwater rivers of the European Alps will face widespread habitat loss, warn researchers.

Many of the species are likely to become restricted to cold habitats that will only persist higher in the mountains, and these areas are also likely to see pressures from the skiing and tourism industries or from the development of hydroelectric plants.

The research study -- led jointly by the University of Leeds and University of Essex -- calls on conservationists to consider new measures to protect aquatic biodiversity.

Invertebrates -- key role in ecosystems

The invertebrates, which include stoneflies, midges and flatworms, play a key role in nutrient cycling and organic matter transfer to fish, amphibians, birds and mammals in the wider Alpine ecosystem.

Using glacier, landscape and biodiversity mapping data collected across the Alps, scientists from across Europe simulated how key invertebrate populations across the mountain range are likely to change between now and 2100 because of climate change.

As the climate warms, the modelling predicted the invertebrate species would seek out colder conditions in the highest parts of the mountain range. In the future, these colder areas are also likely to be prioritised for skiing or tourism or the development of hydropower plants.

Lee Brown, Professor of Aquatic Science at the University of Leeds who co-led the research, said: "Conservationists need to be thinking about how protected area designations must evolve to take into account the effects of climate change.

"It may be that some species will have to be moved to refuge areas if we want to safeguard their survival as many of them are not strong fliers so they cannot disperse easily through the mountains."

Alpine climate is changing rapidly

The research, involving a collaboration between nine European research institutions, brought together data on invertebrate species distribution in the Alps, an area that covers more than 34,000 square kilometres, and mapped it alongside expected changes to glaciers and river flows.

There was sufficient data to model what was likely to happen to 19 invertebrate species, mainly aquatic insects, that live in the cold-water regions of the Alps.

Dr Jonathan Carrivick, from the School of Geography at Leeds who co-led the research, said: "We have quantified that as glaciers melt and retreat, the rivers running through the Alps will experience major changes in their water source contributions.

"In the short term, some will carry more water and some new tributary rivers will form, but over several decades from now -- most rivers will become drier, flow slower and become more stable, and there could even have periods in a year when there is no water flow. Additionally, most water in Alpine rivers will also be warmer in the future."

Losers and winners

By the turn of the century, the modelling predicts that most of the species would have experienced "consistent losses" of habitat.

Those hardest hit are expected to be the non-biting midges, Diamesa latitarsis grp., D. steinboecki, and D. bertrami; the stonefly, Rhabdiopteryx alpina; and mayfly, Rhithrogena nivata.

However, several species are expected to benefit from the habitat changes, including the flatworm, Crenobia alpina and the flat headed may fly, Rhithrogena loyolaea.

Other species would find refuge in new locations. The scientists predict the stonefly Dictyogenus alpinus and the caddisfly Drusus discolor will be able to survive in the Rhone valley in southeast France while other species will be lost from the rivers that flow into the Danube basin.

Conservation

Writing in the paper, the researchers describe the "substantial work" that is necessary to protect the biodiversity in rivers that are being fed by retreating glaciers. The locations where glaciers still exist late in the 21st century are likely to be prioritised for hydropower dam construction and ski resort development.

Dr Martin Wilkes, from the University of Essex and who co-led the research, said: "The losses we predict for Alpine biodiversity by the end of this century relate to just one of several possible climate change scenarios.

"Decisive action by world leaders to reduce greenhouse gas emissions could limit the losses. On the other hand, inaction could mean that the losses happen sooner than we predict."

Understanding how invertebrate populations respond to climate changes is key to understanding how biodiversity in high mountainous areas can be affected, and the techniques developed in the study could be applied to other mountain environments.

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DNA sequence enhances understanding origins of jaws

Researchers at Uppsala University have discovered and characterised a DNA sequence found in jawed vertebrates, such as sharks and humans, but absent in jawless vertebrates, such as lampreys. This DNA is important for the shaping of the joint surfaces during embryo development.

The vast majority of vertebrate species living today, including humans, belong to the jawed vertebrate group. The development of articulating jaws during vertebrate evolution was one of the most significant evolutionary transitions from jawless to jawed vertebrates, taking place at least 423 million years ago. The lower and upper jaws were initially connected by the primary jaw joint. However, during the evolution of mammals this moved to the middle ear to enhance hearing and was replaced by the secondary jaw joint, which is how humans are constructed today.

The primary jaw joint is formed during embryonic development and has an active gene which contains sequence information for a specific protein -- transcription factor Nkx3.2. This protein has long been thought to have played a major role in the evolution of this jaw joint, but little was known before about how its gene activity is regulated in the jaw joint cells.

Typically, genes are activated with help from DNA sequences, known as enhancers, that do not contain gene sequence information. Furthermore, such 'regulatory' DNA can contribute to the activation of the gene only in a certain cell type and can be conserved among different animal species.

"We searched through the genome sequences of many different vertebrate species and only found the DNA sequence near the Nkx3.2 gene in jawed vertebrates -- not in jawless ones. When we injected these DNA sequences from jawed vertebrates into zebrafish embryos, they were all activated in the jaw joint cells. The fact that their ability to activate has been preserved for over 400 million years shows how important it is for jawed vertebrates," notes Tatjana Haitina, researcher at Uppsala University, who led the study.

"In experiments where we deleted the newly discovered DNA sequence from the zebrafish genome using the CRISPR/Cas9 technique, we saw that the early activation of the Nkx3.2 gene was reduced, which caused defects in the jaw joint shape. It turned out that these defects were later repaired, suggesting that there is additional regulatory DNA somewhere in the genome that controls the activation of the Nkx3.2 gene and is waiting to be discovered," adds Jake Leyhr, doctoral student student in the research team.

The researchers hope that their discovery is an important step towards eventually understanding the process behind the origins of vertebrate jaws.

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Do octopuses, squid and crabs have emotions?

Octopuses can solve complex puzzles and show a preference for different individuals, but whether they, and other animals and invertebrates, have emotions is being hotly debated and could shake up humans' moral decision-making, says a York University expert in animal minds.

Most countries don't recognize invertebrates, such as octopuses, crabs, lobsters and crayfish, as sentient beings that can feel pain, but the United Kingdom is considering amendments to its animal welfare legislation that would recognize this.

"A London School of Economics (LSE) report commissioned by the U.K. government found there is strong enough evidence to conclude that decapod crustaceans and cephalopod molluscs are sentient," says York University Professor and philosopher Kristin Andrews, the York Research Chair in Animal Minds, who is working with the LSE team.

Andrews co-wrote an article published today in the journal Science, "The question of animal emotions," with Professor Frans de Waal, director of the Living Links Center at Emory University, which discusses the ethical and policy issues around animals being considered sentient.

Andrews points out it has long been thought in Western culture that other animals don't feel pain or have emotions. "It's been a real struggle even to get fish and mammals recognized under welfare law as sentient. So, it's pretty cutting-edge what seems to be happening in the U.K. with invertebrates."

Pre-verbal human babies were considered not to feel pain up until at least the 1980s. It is still thought by many that animals, including invertebrates, don't feel pain and only have unconscious reactions to negative stimuli. However, research on mammals, fish, octopuses, and to a lesser extent crabs, has shown they avoid pain and dangerous locations, and there are signs of empathy in some animals, such as cows -- they become distressed when they see their calf is in pain.

Recognizing the sentience of invertebrates opens a moral and ethical dilemma. Humans can say what they feel, but animals don't have the same tools for describing their emotions. "However, the research so far strongly suggests their existence," says Andrews, is working on a research project called Animals and Moral Practice.

"When we're going about our normal lives, we try not to do harm to other beings. So, it's really about retraining the way we see the world. How exactly to treat other animals remains an open research question," says Andrews. "We don't have sufficient science right now to know exactly what the proper treatment of certain species should be. To determine that, we need greater co-operation between scientists and ethicists."

There may be a point when humans can no longer assume that crayfish, shrimp, and other invertebrates don't feel pain and other emotions.

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