How rabbits help restore unique habitats for rare species

by University of East Anglia

A rabbit on the University of East Anglia campus.Credit: Tristan Holden, 

University of East Anglia

European wild rabbits are a 'keystone species' that hold together entire ecosystems—according to researchers at the University of East Anglia.

Their grazing and digging activity keeps the ground in a condition that is perfect for sustaining other species that would otherwise move on—or die out.

But their numbers are declining regionally, nationally and globally. And they are even being classed as endangered in their native region, the Iberian Peninsula.

The findings come as efforts to save England's most threatened species from extinction are turning the tide for wildlife in Norfolk and Suffolk thanks to the Shifting Sands project.

Shifting Sands is one of 19 projects across England that make up the national Back from the Brink initiative. Together, these projects aim to save 20 species from extinction and benefit over 200 more.

Lead partner of the rabbit workstream and rabbit expert Prof Diana Bell, from UEA' School of Biology, said: "The Breckland-based Shifting Sands project was set up to save some of the region's rarest wildlife.

"After several years of hard work by this multi-partner project, the fortunes of species classed as declining, rare, near-threatened or endangered are now improving in the Brecks.

"The project has seen species recover in record numbers—including endangered beetle and plants, one of which is found nowhere else in the world.

"Rabbits are incredibly important because their grazing and digging activity keeps the ground in a condition that is perfect for sustaining other species.

"Sadly, rabbit populations have declined dramatically in the UK and across Europe, and the European wild rabbit is now listed as endangered in its ancestral Iberian Peninsula range. Their decline is largely due to a spill-over of new viruses from commercially bred rabbits.

"The Shifting Sands project has shown us how important rabbits are to entire ecosystems, and it is vital that these habitats are conserved and protected.

"We encouraged a rabbit revolution in the Brecks and we have produced a toolkit in partnership with Natural England to help landowners of similar rabbit-dependent habitats to do the same."

"Simple cost-effective ways of encouraging rabbits include creating piles of felled branches, known as brush piles, and banks of soil."

Monitoring over the past three years has shown the interventions are working, with evidence of significantly higher amounts of rabbit activity.

Prof Bell said: "Our work resulted in evidence of rabbit activity in significantly higher numbers. 91 percent of brush piles showed paw scrapes and 41 percent contained burrows. Even when burrows did not form, the brush piles helped expand the range of rabbit activity."

The UEA research team worked in collaboration with Natural England, Forestry England, Plantlife, Breckland Flora Group, Norfolk Wildlife Trust, Suffolk Wildlife Trust, Butterfly Conservation, Buglife, the Elveden Estate and the RSPB to deliver this ambitious partnership project.

It has seen five kilometers of 'wildlife highways' created, more than 100 specimens of rare plants re-introduced, habitat created and restored across 12 sites, species encouraged, and landscape-management practices improved.

As a result, seven species of plant, bird and insect are increasing in number and many more are benefiting in turn.

Among those species recovering are rare plants such as the prostrate perennial knawel that is unique to the Brecks, basil thyme and field wormwood. The endangered wormwood moonshiner beetle, lunar yellow underwing moth and five-banded digger tailed wasp are also increasing. All these species are identified in the UK's Biodiversity Action Plan as being priorities for conservation.

The open habitat maintained by rabbits supports two rare plants: the prostrate perennial knawel—found nowhere else in the world—and field wormwood.

Pip Mountjoy, Shifting Sands project manager at Natural England, said: "The Brecks were described by Charles Dickens as "barren." They are anything but. Their 370 square miles of sandy heathland, open grassland and forest support almost 13,000 species, making it one of the UK's most important areas for wildlife.

"That wildlife is under threat. Felling trees and encouraging a species that is often considered a pest may seem a strange solution. But in this instance, carefully managed 'disturbance' is exactly what this landscape and its biodiversity needs."

"The project's interventions have provided a lifeline for this unique landscape, and shown how biodiversity can be promoted by 'disturbing' places—not just by leaving them alone. "

"These rare habitats are becoming overgrown and species are declining as a result of changing land management practices and human impacts. It's our responsibility to restore and maintain these spaces for nature. Some of these species exist only here and, if lost, will be lost forever.Feds say New England cottontail doesn't need protection

More information: More information about the Brecks, Shifting Sands, Back from the Brink and a toolkit to help rabbit conservation is available via https://naturebftb.co.uk/wp-content/uploads/2021/09/Shifting-Sands-Techniques-to-encourage-European-rabbit-recovery.pdf

Provided by University of East Anglia 

 

Catastrophic consequences for oceans when climate change and plastic pollution crises combine

by Bangor University

Credit: Dan Bayley

ZSL (Zoological Society London) and Bangor University have revealed fundamental links between the global climate crisis and plastic pollution, including extreme weather worsening the distribution of microplastics into pristine and remote areas.

The ocean, its ecosystems and species are commonly the focus of plastic pollution research or climate change research; however, the compounding impact of how they act together is often overlooked.

In a paper published today in Science of the Total Environment, an interdisciplinary team of scientists have for the first time, collated evidence that the global issues of marine plastic pollution and climate change exacerbate one another, creating a dangerous cycle, and are urging governments and policy makers to tackle the two issues in unison.

Connecting plastic pollution and climate change

The team identified three significant ways that the climate crisis and plastic pollution—a significant driver of marine biodiversity loss—are connected, with the first being how plastic contributes to global greenhouse gases (GHGs) throughout its life cycle, from production through to disposal. The second demonstrates how extreme weather, like floods and typhoons associated with climate change will disperse and worsen plastic pollution. With plastic pollution and the effects of climate change being major issues for our ocean, seas, and rivers, the third point examines the marine species and ecosystems that are particularly vulnerable to both.

Credit: Heather Koldewey

Plastic pollution is having a devastating impact on marine biodiversity—from individual animals mistakenly ingesting plastic bags to entire habitats polluted with microplastics. Mainly sourced from fossil fuels, and with global demand set to rise, the production of plastic is predicted to emit more than 56 billion Mt of carbon dioxide in GHGs between 2015–2020, which is 10–13% of the entire remaining carbon budget.

Climate change is already causing more extreme weather events including storms and flooding which increases the dispersal of mismanaged waste between land and sea. In addition, sea ice is a major trap for microplastics which will be released into the ocean as the ice melts due to warming.

Public awareness and media coverage of both issues has risen exponentially over the years, but studies show that they are often approached as separate, even competing issues. Professor Heather Koldewey, Senior Technical Specialist at ZSL and the senior author on the paper says that integrated solutions to mitigate against both crises are possible and must be considered.

Professor Koldewey said: "Climate change is undoubtedly one of the most critical global threats of our time. Plastic pollution is also having a global impact; from the top of Mount Everest to the deepest parts of our ocean. Both are having a detrimental effect on ocean biodiversity; with climate change heating ocean temperatures and bleaching coral reefs, to plastic damaging habitats and causing fatalities among marine species. The compounding impact of both crises just exacerbates the problem. It's not a case of debating which issue is most important, it's recognizing that the two crises are interconnected and require joint solutions."

The study demonstrates how vulnerable species and habitats which are impacted by, and can have an impact on climate change, are also threatened by plastic pollution, such as sea turtles and corals. It says that further research is needed to determine these links, their roles in our natural environment, and how both issues interact to negatively impact ecosystems.

Credit: Dan Bayley

Professor Koldewey added: "The biggest shift will be moving away from wasteful single-use plastic and from a linear to circular economy that reduces the demand for damaging fossil fuels."

Helen Ford, Ph.D. researcher at Bangor University who led the study said: "As coral reefs are the focus of my research, I am reminded daily of how vulnerable these marine ecosystems are to climate change. I have seen how even the most remote coral reefs are experiencing widespread coral death through global warming-caused mass bleaching. Plastic pollution is yet another threat to these stressed ecosystems.

"Our study shows that changes are already occurring from both plastic pollution and climate change that are affecting marine organisms across marine ecosystems and food webs, from the smallest plankton to the largest whale. We need to understand how these threats to ocean life will interact as they build and encourage policy-makers to act to address these global threats."

The recognition that global environmental crises are intrinsically linked is increasing. A recent ZSL-led study which was also co-authored by Professor Koldewey, stressed that both the climate change and biodiversity crises must be tackled in unison to avoid falling short on solutions, and suggests ways in which several nature-based solutions could address bothMangroves threatened by plastic pollution from rivers, new study finds

More information: Helen V. Ford et al, The fundamental links between climate change and marine plastic pollution, Science of The Total Environment (2021). DOI: 10.1016/j.scitotenv.2021.150392

Journal information: Science of the Total Environment 

Provided by Bangor University 

Gray whale hormones give off distress signal

by Angela Nicoletti, Florida International University

Credit: Unsplash/CC0 Public Domain

Certain hormones in gray whales could act as a distress signal, revealing how whales cope when it's harder for them to find food.

Florida International University (FIU) postdoctoral researcher in the Institute of Environment Leila Lemos found that T3—a thyroid hormone connected to metabolic activities—tends to increase when gray whales are stressed, skinny and malnourished.

This finding was somewhat unexpected. Previous studies on orcas and humpback whales have found that T3 increases with feeding. Lemos expected that the gray whales she studied off the coast of Oregon to have higher T3 levels when they had more access to food and were in better shape. But, they didn't.

"Depending on the season and its prey availability, whales could either be chubby and 'relaxed' or skinny and 'stressed,'" Lemos said. "We still found a negative relationship between body condition and cortisol levels, which was what was expected—meaning that skinnier and possibly hungry whales were more stressed than the chubby ones. According to the literature, we expected to find a positive correlation between T3 and body condition, but we found the opposite."

The reason for this is connected to the fact that T3 is also tied to other metabolic activities like the regulation of body temperature or the use of available energy sources. Since whales have blubber to keep their temperature steady, increased T3 in whales with poorer body condition could be tied to the use of carbohydrates as an energy source. A whale's T3 would increase when stressed, because it would need another energy source to survive, especially if food is scarce.

This study provides important insight into what happens inside of whales. After all, not much is known, because gathering samples to unravel the mystery is a bit of a challenge.

The particular sample Lemos was in search of requires a lot of waiting. First, she has to wait for the gray whales to appear and get close enough to her boat. Then, she has to wait for nature to call. Yes, she's waiting for them to poop.

For scientists like Lemos, the fecal samples are precious, because they reveal what the whales' body condition alone can't—what is happening with the hormones.

In total, Lemos collected more than 70 samples from 36 gray whales. The majority had higher levels of T3 and cortisol, which corresponds to environmental data that reveals changes that could have interfered with the whales' ability to find food.

More monitoring, like this, is urgently needed to provide a clearer understanding about the challenges whales face in today's rapidly changing environment—a fact that became more evident in the past few years after hundreds of gray whales stranded themselves.

"It's critically important to assess the physiological state of this population simultaneously with environmental data to identify potential causes for unusual, tragic events such as this," Lemos said. "This information can help us develop better conservation strategies to protect the species."

The findings were published in Marine Mammal Science.

Man-made chemicals could be stressing out marine mammals

More information: Leila S. Lemos et al, Stressed and slim or relaxed and chubby? A simultaneous assessment of gray whale body condition and hormone variability, Marine Mammal Science (2021). DOI: 10.1111/mms.12877Journal information: Marine Mammal Science 

Provided by Florida International University 

Zoo Miami: Orangutan dies following dental surgery

This photo provided by Zoo Miami shows orangutan Kumang. Kumang, a 44-year-old 

Bornean orangutan, died Thursday, Sept. 23, 2021, during recovery from anesthesia. 

Credit: Ron Magill/Zoo Miami via AP

An orangutan has died at Zoo Miami following a dental surgery, officials said.

Kumang, a 44-year-old Bornean orangutan, died Thursday during recovery from anesthesia, according to a statement from the South Florida zoo.

"We at Zoo Miami are heartbroken over this terrible loss and our deepest condolences go out to the staff that provided Kumang with such great care over the years," the statement said.

The great ape had been anesthetized for the removal of two teeth, which were damaged and causing an infection in her gums, official's said. The anesthesia, examination and dental care went as planned. Kumang was closely monitored by veterinarians, veterinary technicians and a human cardiologist. Her vitals remained stable, officials said.

After the procedure, Kumang was returned to her enclosure, where she began to recover. Zoo workers said she was able to sit up and climb to her platform bed. But then for unknown reasons, she lied down and stopped breathing, officials said. Efforts to resuscitate Kumang, including CPR, were unsuccessful. Officials said a thorough necropsy will be performed to determine the cause of death.

This photo provided by Zoo Miami shows orangutan Kumang, left. Kumang, a 44-year-old

 Bornean orangutan, died Thursday, Sept. 23, 2021, during recovery from anesthesia. 

Credit: Ron Magill/Zoo Miami via AP

Kumang leaves behind an 8-year-old daughter named Bella, who continues to reside at Zoo Miami.

Bornean orangutans are considered endangered, with a global population of just over 100,000. They can be found in the wild in Malaysia and Indonesia on the Asian island of Borneo.

Testing times: Borneo orangutans get COVID swabs

© 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

'I don't think I can cope financially': People are putting off parenthood because of austerity

by Sarah Marie Hall, The Conversation

The birth rate in England and Wales is now the lowest it has ever been since records 

began. Credit: Shutterstock

Britain's birth rates are plunging. The number of babies being born has been in steep decline since 2017. Now, researchers are investigating early signs that the pandemic may have caused rates to drop even further.

This is not totally surprising given the difficult economic conditions that have come with the pandemic—history also shows that economic uncertainty has long been associated with reduced birth rates.

The birth rate in the UK has been declining year on year since 2013 and has been linked to the austerity measures implemented by the government in response to the 2008 global financial crisis.

Austerity cuts have decimated social care, welfare and local government. They have led to rising rents (private rents increased by 24% between 2010 to 2017), shrinking social housing stock, adults living or moving back home with parents, along with more people precariously employed, due to insecure forms of work and retreating state support. Such inequalities have seeped into the fabric of everyday life. And these austerity measures have been particularly acute for young people growing up over the past ten years.

As part of my recent research, I looked at how austerity has influenced people's decisions around having children. I carried out in-depth interviews with 12 people living in the North East of England—a region that has some of the lowest birth rates in the UK—and that has been significantly damaged by austerity.

Altered reproductive plans

All the people I spoke to had been deeply affected by the government's austerity measures. They told me how the cuts in spending and the economic climate had altered their reproductive plans. Vihaan was not alone when he told me how he and his partner had put their plans on hold because of issues with "financial planning, stability…and having enough of a financial back up so that we can afford a decent life."

Many people I spoke with also found it hard to know whether to have children—or more children if they already had a child. Austerity had affected their intimate relationships and changed their feelings about what their future might hold.

They spoke a lot about their worries for the future. Most of these worries were based on financial insecurity—concerns about secure and appropriate housing, steady employment—as well as meaningful and healthy relationships.

They also spoke about the sheer pressure of carrying these worries, keeping them in check and at the same time holding together hopes for their unknown reproductive futures.

One participant, Lauren, said she worries about financial instability—particularly her partner's debt—and how this will affect their future. Like many other participants, Lauren spoke about wanting to do more than just survive: "I want to be in the position in the future where I do have a kid, that I think I can give it everything it wants. I don't want to have to scrimp and save to be able to give it a life."

Similarly, Jonny spoke about his worries of needing to feel ready and prepared if they were to have a child. For him and his partner, this included having certain material and practical elements in place—housing, childcare and income—before feeling able to make a decision.

He described this as "sorting ourselves out" and spoke about all the decision making this involved: whether to have children or not, whether to stay living where they are now or to move closer to his mum, along with whether to keep his stable job or to risk setting up his own business. He talked about "putting real thought" into these decisions and "weighing them up."

Limited choice

For the people I interviewed, and many others like them, a combination of personal circumstances and government cuts in spending have made their futures less certain. And for some, it has taken away the possibility of having children—or more children—because of ongoing financial concerns and worries.

Sze-Kei described the impact of austerity measures on her family, saying: "at the back of your mind, you have to think about the financial side of things." She talked about how she hoped to have another child in the future but she worried about if they could afford it. She spoke about how she wanted to remember how hard it is to raise children and how she felt about being pregnant the first time. Sze-Kei also seemed to bear this worry more than her husband, saying "I don't think I can cope financially."

In this way, it is important to recognize that austerity policies not only directly affect people's lives and decision making, but they ultimately shape people's life course—with those on the lowest incomes often hit hardest. And given the ongoing uncertainty as a result of the pandemic, along with the fact that poor young people have been the hardest hit by COVID, this may well be a trend that continues for some time to come.Cuts to children's support centres in England linked to thousands more kids with obesity

Provided by The Conversation 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Genetics show global fisheries management should re-think tiger sharks

by Save Our Seas Foundation

New genomic research confirms two highly distinct tiger shark populations worldwide. Credit: Nicola Poulos | Save Our Seas Foundation

A tiger shark's life history is one painted with broad brush strokes. These sharks are generalists of the boldest kind. Found in tropical and subtropical seas worldwide, they live in a range of ocean habitats from shallow coastal waters to mysterious depths far offshore. Their diet is equally unfussy and has become the stuff of legend, its menu of marine mammals, fish, seabirds and other sharks peppered with garbage and terrestrial animals, according to some reports. Everything points to the kind of shark that can travel widely, mix freely and therefore (in theory) interbreed. We would expect populations to be similar to one another.


However, new research published on 10 August 2021 in the Journal of Heredity, with Dr. Andrea Bernard from Nova Southeastern University as the lead author, confirms the opposite: that tiger sharks in the Atlantic are genetically very different from those in the Indo-Pacific Ocean. "These results mean that Atlantic and Indo-Pacific tiger sharks, despite their ability to travel vast distances, have not intermingled to reproduce for a long time," explains Professor Mahmood Shivji, the director of the Save Our Seas Shark Research Centre (SOSF-SRC) and a co-author of this study. "This long-term separation between Atlantic and Indo-Pacific tiger sharks has resulted in them developing into separate populations, each with its own unique genetic diversity," he says. The study also confirmed findings that tiger sharks from Hawaii, one of the world's most geographically isolated archipelagos, are genetically different from Indian Ocean tiger sharks.

The SOSF-SRC focuses on employing cutting-edge science to improve the conservation of sharks and rays. Its speciality lies in using genetics to understand these species and apply new knowledge to improve their protection. As its director, Professor Shivji has to consider what shapes their mission. "A guiding principle for our work is to focus primarily on shark species that are of high conservation concern. We spread our work across both discovery research questions (for instance, understanding how sharks function) and applied conservation research (for instance, understanding interactions between shark migration patterns and fisheries or investigating trade in shark parts). The important point is that all of this information advances our knowledge of sharks and informs conservation."

Tiger sharks in Mozambique have been recorded traveling thousands of kilometers to the other side of the Indian Ocean, but are genetically distinct from those in the Atlantic. Credit: Nick Filmalter

Large tiger sharks overwinter in the Bahamas and migrate thousands of kilometers into open ocean in the summer, but remain in the Atlantic. Credit: Christopher Vaughan-Jones


Tiger sharks are essential players in the ocean system, but their way of life throws them into the path of fishing vessels. Their home is also changing rapidly; climate change, pollution and habitat destruction mean that for species to survive, they need to adapt—and fast. "Overfishing poses a clear danger to sharks. The genetic diversity in overfished species will inadvertently be diminished and they won't adapt to the fast pace of environmental change," confirms Professor Shivji. "Compared to other fish species, tiger sharks occupy an unusually wide variety of habitats. Given their influential ecological role and their widespread movements that expose them to a variety of fisheries, science-informed fisheries management of tiger sharks is important to achieve global conservation goals."

The researchers in this study were able to scrutinize the structure of tiger shark populations at a finer resolution than is usual. Instead of being reliant on mitochondrial DNA (the DNA found in the energy-making mitochondria that power our cells and are only inherited through mothers), the study used genome-scale (the full genetic information apparent in an individual) single nucleotide polymorphisms (SNPs). "SNPs repeat across the entire genome," explains Professor Shivji. "This increases the amount of information for geneticists to work with relative to previous surveys that were limited to small subsections of genetic information." The result is much higher precision in distinguishing which tiger shark populations are genetically distinct.

With what we now know, the Atlantic and Indo-Pacific tiger shark populations will need tailored management plans and, concludes Professor Shivji, 'targeted conservation efforts to preserve their genetic diversity and potential to survive rapid changes occurring in our oceans." The study recommends that international fishery management of tiger shark populations consider the Atlantic and Indo-Pacific populations as separate and that a targeted conservation plan is devised for Hawaiian tiger sharks.

The more we know about sharks, the better we are able to refine our own behavior, policies and management interventions to suit their particular challenges. "Tiger sharks are part of not only the ocean's overall health, but also its beauty and wonder. Our ongoing mission at the SOSF is to know more in order to do better by these species and their ocean home. Improving our insights into tiger sharks is ultimately linked to our health and well-being," says the founder of the SOSF, His Excellency Abdulmohsen Abdulmalik Al-Sheikh. If our understanding of tiger sharks had remained that populations are similar wherever they are found across the oceans, we might have stood to lose their true diversity and undermined their resilience as a powerful and ancient species.Older than expected: Teeth reveal the origin of the tiger shark

More information: Andrea M Bernard et al, Genomic Assessment of Global Population Structure in a Highly Migratory and Habitat Versatile Apex Predator, the Tiger Shark (Galeocerdo cuvier), Journal of Heredity (2021). DOI: 10.1093/jhered/esab046

Journal information: Journal of Heredity

Provided by Save Our Seas Foundation

How geology and climate shape biodiversity

by Peter Rüegg, ETH Zurich

In the tropics of South America, biodiversity is much higher than in Africa - in the picture:

 a chestnut-mandibled Toucan. Credit: Andy Morffew via Wikimedia Commons

Tropical rainforests are the most biodiverse habitats on Earth. They are home to a huge number of different plants, animals, fungi and other organisms. These forests are primarily spread over three continents, concentrated in the Amazon Basin in South America, the Congo Basin in Central Africa, and the vast archipelago of Southeast Asia.

It might seem that all tropical rainforests are about equally diverse due to their stable warm and humid climate and their geographical location around the equator—but this is not the case. Compared to South America and Southeast Asia, the number of species in Africa's humid tropical forests is significantly lower for many groups of organisms.

Palms with few species

A good illustration of this uneven distribution—what researchers refer to as the pantropical diversity disparity (PDD) – is palm trees: Of the 2,500 species worldwide, 1,200 occur in the Southeast Asian region and 800 in the tropical forests of South America, but only 66 in African rainforests.

Why this should be so is debated among biodiversity researchers. There is some evidence that the current climate is the cause of the lower species diversity in Africa's tropical forests. The climate in Africa's tropical belt is drier and cooler than that in Southeast Asia and South America.

Other evidence suggests that the different environmental and tectonic histories of the three tropical forest regions over tens of millions of years had an impact on the differing levels of biodiversity. Such environmental changes include, for example, the formation of mountains, islands, or arid and desert areas.

However, it is difficult to distinguish between the two factors of current climate and environmental history.

Mountain building brings up diversity

Led by Loïc Pellissier, professor of landscape ecology, researchers at ETH Zurich have now investigated this question with the help of a new computer model that allows them to simulate species diversification over millions of years of evolution. They conclude that the current climate is not the main reason that biodiversity is lower in the rainforests of Africa. Rather, biodiversity has emerged from the dynamics of mountain building and climate change. The results of the historical simulations largely coincide with the patterns of biodiversity distribution observable today.

"Our model confirms that differences in palaeoenvironmental dynamics produced the uneven distribution of biodiversity, rather than current climatic factors," says Pellissier. "Geological processes as well as global temperature fluctuations determine where and when species emerge or go extinct."

One factor in particular is crucial to high biodiversity on a continent: geological dynamics. Active plate tectonics promote both the formation of mountains, such as the Andes in South America, and the emergence of archipelagos, as in Southeast Asia. These two processes result in many new ecological niches, which in turn give rise to numerous new species. Africa's rainforest belt, on the other hand, has had less tectonic activity over the past 110 million years. It is also relatively small because it is bordered by drylands in the north and south, limiting its spread. "Species from humid regions can hardly adapt to the dry conditions of the surrounding drylands," Pellissier points out.

Geologically vibrant continents produce higher biodiversity

The gen3sis model developed by ETH researchers was recently presented in the journal PLoS Biology. It is a mechanistic model in which the primary constraints such as geology and climate are represented together with biological mechanisms and from which biodiversity patterns can materialize. To simulate the emergence of biodiversity, the most important processes to integrate into the model are ecology (i.e. each species has its own limited ecological niche), evolution, speciation and dispersal.

"With these four basic rules, we can simulate the population dynamic of organisms over shifting environmental conditions and offer a very good explanation for how the organisms came about," Pellissier says.

By building their model on these basic evolutionary mechanisms, the researchers can simulate species diversity without having to input (distribution) data for each individual species. However, the model requires data on the geological dynamics of the continents under consideration, as well as humidity and temperatures from climate reconstructions.

The researchers are now refining the model and running simulations to understand the emergence of biodiversity in other species-rich regions, such as the mountains of western China. The model's code and the palaeoenvironmental reconstructions are open source. All interested evolutionary and biodiversity researchers can use it to study the formation of biodiversity in different regions of the world.

Tropical coral species at extreme risk from climate change

More information: Hagen O, Skeels A, Onstein R, Jetz W, Pellissier L., Earth history events shaped the evolution of uneven biodiversity across tropical moist forests. PNAS, Publication date: Oct 1st 2021.

Oskar Hagen et al, gen3sis: A general engine for eco-evolutionary simulations of the processes that shape Earth's biodiversity, PLOS Biology (2021). DOI: 10.1371/journal.pbio.3001340

Journal information: PLoS Biology , Proceedings of the National Academy of Sciences 

Provided by ETH Zurich 

Study reveals the impact of human settlement on island ecosystems

by University of Southampton

Laurel forest, La Gomera (Canary Islands). Credit: Sandra Nogué

Research has shed new light on the impact of humans on islands' biodiversity. The findings show how human colonization altered forest across the islands of Macaronesia including the loss of landscape authenticity.

Oceanic island ecosystems are unique and often contain species that are limited to specific islands or island groups.  They are also vulnerable to disturbance.

To provide a timeline of how humans changed these territories over the centuries, a team led by the University of Southampton, studied multiple indicators of landscape change buried in sediments deposited over periods of up to ten thousand years. The team examined samples including fossilized pollen, spores of dung-decomposing fungi that indicate the presence of sizable herbivores, fragments of charcoal indicating use of fires as well as the composition of the sediment itself.

Their findings, published in the journal PNAS, showed that while forests on the islands changed naturally over thousands of years, human arrival on the Canary Islands, around 2000 years ago, and Cabo Verde, 500 years ago, led to an increase in fires and rates of soil erosion, the latter associated with the introduction of non-native livestock such as goats and pigs. One particular type of forest typical of Macaronesia, known as thermophilous forest, and characterized by iconic species such as the dragon tree, was most impacted. In Cabo Verde, data suggest that island vegetation is suffering a process of homogenisation due to human pressures and the uniqueness of individual island ecosystems is being lost. 

Fieldwork in Cabo Verde. Credit: Sandra Nogué

The team also found that the first use of Canarian forests by aboriginal settlers appeared to have limited impact on the native vegetation, such as the laurel forest of the island of la Gomera. This is possibly due to smaller populations, typically interacting and trading with other nearby islands. By contrast, colonial era settlers who arrived in the 15th Century, adopted much more aggressive acts of deforestation, change in land use, and introduction of non-native species due to much wider trading networks which had a much greater affect.  

Dr. Sandra Nogué Bosch, Lecturer in Palaeoenvironmental Science at the University of Southampton said, "Contrasting the long-term history of different ecosystems, such as island forests, helps put in perspective the transformative force that humankind is unleashing all around the world."

Prof Mary Edwards, Professor of Physical Geography at the University of Southampton said, "we hope that local and international institutions tackling environmental challenges in the region can use new knowledge about past ecosystem composition and variability to restore natural parks and other parts of island landscapes."

Dr. Alvaro Castilla-Beltrán, who completed his Ph.D. at the University of Southampton explained, "This evidence about past environments provides valuable evidence on how forests responded to human actions and how best to go about restoring these landscapes, which have in some cases suffered severe transformations and species loss."

Alvaro Castilla-Beltrán on fieldwork in Brava, Cabo Verde. Credit: Autylio Gonçalvez

The team plans to keep using cutting-edge methodologies to be able to answer these questions, unleashing the potential of geochemical tools and searching for ancient DNA preserved in in sediments.

Having analyzed the consequences of human impacts on the Canary Islands and Cabo Verde, the team plan to continue their studies on other archipelagos to delve further into how island habitats have evolved.

"Other important research questions remain open, for example, what was the role of a changing climate in these processes in the past, and how will global warming affect future ecosystems? What was the local impact of extreme natural phenomena such as volcanic eruptions—like the one currently active in La Palma—and how did island life change the cultures of those people that settled them? We will also keep up the work on other archipelagos to provide a new perspective of the human footprint in these fascinating territories," Dr. Nogué Bosch concluded.Study reveals extent of human impact on the world's plant-life

More information: Alvaro Castilla-Beltrán et al, Anthropogenic transitions from forested to human-dominated landscapes in southern Macaronesia, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2022215118

Journal information: Proceedings of the National Academy of Sciences 

Provided by University of Southampton 

Evaluating bacterial communities in freshwater for their ability to break down crude oil and diesel fuel

by Kelley Christensen, Michigan Technological University

Two of the experimental microcosms in the Techtmann lab. Credit: Steve Techtmann

Bacteria that can consume oil or fuel have been used to help clean up spills in the ocean, but their use in freshwater has been limited by a lack of research. A Michigan Technological University professor and his students have set out to change that, studying colonies of bacteria in the Straits of Mackinac to determine what conditions they need to thrive.

Steve Techtmann, an expert in identifying bacteria that can be used to clean up various kinds of waste, has determined the community is, at least in a laboratory setting, capable of degrading crude oil and diesel fuel. The results of Techtmann and his students' study are published in the Journal of Great Lakes Research. But, since both oil and fuel are regularly transported by ship and near lakes and rivers, this discovery has important implications for freshwater contaminant spills across the world. Understanding what happens to oil when it's released in water can help emergency responders and government react quickly and more effectively.

"Bacteria help to break down oil that couldn't be cleaned up through physical means like skimming," Techtmann said. "A lot of the methods for oil spill cleanup rely on these types of bacteria for oil that humans can't recover."

Tiny terrariums and hydrocarbon snacks

To create an environment in which the bacterial samples could flourish or fail, students including Kayley Roche, a biochemistry major who plans to graduate this December, set up glass bottles containing a volume of lake water. They added a certain amount of either crude oil or diesel fuel, then sealed them shut with a rubber stopper.

"Every week we would take a bunch of the bottles and measure the carbon dioxide in them," Roche said. "We saw carbon dioxide production increasing as the microbes had more time to break down the oil in the bottle."

The scientists poked a needle through the rubber stopper to pull out enough air to measure the carbon dioxide inside. They used gas chromatography to measure the chemical signature in the air samples.

"We used carbon dioxide production as a proxy to measure hydrocarbon metabolism by the microbes," Roche said. "Carbon dioxide is respired by the microbe, and its measurement can help correlate microbial metabolism with the breakdown of the hydrocarbons in the oil."

Even bacteria need an offseason

But cleaning a freshwater spill isn't as easy as releasing the bacteria then heading to the beach. The clean-up effectiveness of the bacterial colonies Techtmann and others in his lab identified depends on the season, community makeup and availability of certain nutrients.

If the bacteria in a given bottle multiplied after the addition of oil or fuel, the researchers knew the microorganisms were the type that could survive and thrive in the presence of contaminants. The team then investigated how other variables affected the bacteria in each bottle.

"Temperature is a major thing that affects the bacterial metabolism," Techtmann said. "In this experiment, we simulated conditions in the winter by incubating water at cold temperatures," he continued, noting that the bottles were held at either 4 or 23 degrees Celsius (39.2 to 73.4 degrees Fahrenheit). "The oil in the bottles incubated at colder temperature broke down more slowly."

Other factors can affect the bacteria's appetite, too—including the nutrients they have available, such as nitrogen and phosphorus, as well as carbon from the oil or diesel fuel. Lower nutrient availability also slowed the rate of contaminant breakdown.

"We also found that there were different groups of bacteria that responded to oil at different times of the year. For example, there was a spring-specific community or fall-specific community, and then a year-round community of bacteria," Techtmann said.

Champions of the oil-eating contest

Now that a specific community of bacteria has been identified, Techtmann and students will investigate how quickly the Straits bacteria can process crude oil or fuel, and what other environmental conditions might affect the bacteria's effectiveness.Emma Byrne, who graduated from Michigan Tech this year with a master's degree in biological sciences, analyzed the data collected from the microcosm experiment along with other students from the lab. Byrne is now an environmental quality analyst for the Michigan Department of Environment, Great Lakes and Energy.

"This research is important because the impacts of oil spills in freshwater environments, particularly the Great Lakes, are understudied," Byrne said. "Understanding how the environment might fluctuate in the event of an oil spill could help us predict the impacts."

Techtmann concurred. "We know so much about this process in the oceans, but we know relatively little about this process in freshwater, yet we rely on freshwater so much."

Marine bacteria in Canadian Arctic capable of biodegrading diesel and oil

More information: Emily R. Byrne et al, Temporal variation of crude and refined oil biodegradation rates and microbial community composition in freshwater systems, Journal of Great Lakes Research (2021). DOI: 10.1016/j.jglr.2021.08.003

Provided by Michigan Technological University