Lander T.A.,University of Oxford |
Lander T.A.,French National Institute for Agricultural Research |
Bebber D.P.,Earthwatch Institute |
Choy C.T.L.,University of Oxford |
And 2 more authors.
Current Biology | Year: 2011
Global declines in pollinators, associated with land-use change [1-6] and fragmentation [7-10], constitute a serious threat to crop production and biodiversity . Models investigating impacts of habitat fragmentation on pollen flow have categorized landscapes simply in terms of habitat and nonhabitat. We show that pollen flow depends strongly on types of land use between habitat fragments. We used paternity analysis of seeds and a combination of circuit and general linear models to analyze pollen flow for the endangered tree Gomortega keule (Gomortegaceae)  in the fragmented Central Chile Biodiversity Hotspot . Pollination probability was highest over pine plantation, moderate over low-intensity agriculture and native forest, and lowest over clearfells. Changing the proportions of the land uses over one kilometer altered pollination probability up to 7-fold. We explain our results by the novel "Circe principle." In contrast to models where land uses similar to native habitat promote pollinator movement, pollinators may actually be waylaid in resource-rich areas between habitat patches. Moreover, pollinators may move with higher probability between habitat patches separated by some resource-poor land uses. Pollination research in fragmented landscapes requires explicit recognition of the nature of the nonhabitat matrix, rather than applying simple binary landscape models. © 2011 Elsevier Ltd All rights reserved.
News Article | February 15, 2017
As the climate changes and fisheries transform the oceans, the world's African penguins are in trouble, according to researchers reporting in Current Biology on February 9. Young penguins aren't able to take all the changes into account and are finding themselves "trapped" in parts of the sea that can no longer support them even as better options are available. "Our results show that juvenile African penguins are stuck foraging for food in the wrong places due to fishing and climate change," says Richard Sherley (@rbsherley) of the University of Exeter and University of Cape Town. "When the young of this endangered species leave the colony for the first time, they travel long distances, searching the ocean for certain signs that should mean they have found an area with lots of plankton and plenty of the fish that feed on it. But rapid shifts caused by climate change and fishing mean these signs can now lead them to places where these fish, the penguins' main prey, are scarce with impacts on their survival--a so-called 'ecological trap.' "Protecting the penguins--and other species--from falling into similar ecological traps will require better action to account of the needs of predators in managing fisheries and concerted action to tackle climate change." Sherley and colleagues, including Stephen Votier, also at the University of Exeter, and scientists from the Namibian and South African governments, made the discovery after using satellites to track the dispersal of newly fledged African penguins from eight sites across their breeding range. They wanted to find out whether the penguins were being trapped in what's known as the Benguela Current Large Marine Ecosystem (BCLME). The BCLME is one of four major eastern boundary upwelling ecosystems of the world, Sherley explains. This portion of the ocean stretches from near the Angola-Benguela front in southern Angola in the north to Cape Point in South Africa's Western Cape. It has historically also been one of the most productive ocean areas in the world, rife with anchovies and sardines, which make good food for penguins and for people. In recent decades, overfishing in Namibia, heavy localized fishing, and subsequent environmental change have reduced the number of sardines and changed the areas that the fish use. In addition, fish and plankton are no longer reliably found together as they were in the past. The problem is that no one told the penguins. "The penguins still move to where the plankton are abundant, but the fish are no longer there," Sherley says. "In particular, sardines in Namibia have been replaced in the ecosystem by lower-energy fish and jellyfish." The researchers developed models to show that the penguins travel over thousands of kilometers to find areas where sea surface temperatures are low and chlorophyll concentrations are high, a sign that should mean plenty of plankton and the fish that go with them. The researchers don't yet know for sure, but they suspect that the penguins are responding to substances given off by phytoplankton when they are under stress, as occurs when they are being grazed on by predators. "These were once reliable cues for prey-rich waters, but climate change and industrial fishing have depleted forage fish stocks in this system," Sherley says. Young penguins that find themselves in the degraded Benguela ecosystem today often fail to survive. Their breeding numbers are about 50% lower than they would be if they found their way to other waters, where the human impact has been less severe, the new study shows. Sherley and Votier say it might be possible to protect the penguins by translocating chicks to a place where it's not possible to get trapped. They say there is some evidence that fledglings from the colonies in South Africa's Eastern Cape generally don't get caught in the trap, at least not yet. There are other options, too, such as building spatial fishing closures in key areas where the penguins feed or otherwise increasing the number of sardines in the area. Sherley says the South African government is working to implement spatially explicit catch limits and management practices in their sardine fishery, which will almost surely help. The researchers are helping to inform their decisions with the penguins in mind. Meanwhile, their work to understand how fishing influences the interactions between seabirds and their prey at different spatial scales and at different phases of the birds' lifecycle and how to protect them continues. This work was supported by the Natural Environment Research Council, Bristol Zoological Society, Earthwatch Institute, Leiden Conservation Foundation, the Southern African Foundation for the Conservation of Coastal Birds, and the authors' institutions. Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www. . To receive Cell Press media alerts, contact email@example.com.
News Article | December 8, 2016
RENO, Nev. - Turning meadow restoration into cleaner air is the goal of researchers at the University of Nevada, Reno. The Soil Science Laboratory at the University recently partnered with the Earthwatch Institute, an international citizen science research organization, to better understand how restoration and plant communities relate to the soil carbon in Sierra Nevada mountain meadows. "Since Euro-American settlement, plant and water resources in meadows have been manipulated. There aren't many pristine meadows left in much of the Sierra Nevada mountains," Ben Sullivan, soil scientist and biogeochemist with the University of Nevada, Reno, said. "As a consequence of the disturbances, meadows are losing carbon, in the form of carbon dioxide, to the atmosphere that was once stored in the soil for long periods of time." Many meadows have been disturbed by human use, resulting in lower water tables and drier soil conditions. As a result, soil carbon can be decomposed by microbes, resulting in production of carbon dioxide, a greenhouse gas. However, trees and shrubs take up the carbon dioxide, and dry, disturbed meadows often have trees and shrubs establishing in these formerly wet ecosystems. People often see the carbon in the trees and think that degraded meadows have more carbon. But that doesn't consider the much greater amount of carbon in the soil, and the carbon dioxide balance isn't acre for acre. "One acre of degraded meadow releases as much carbon dioxide as 11 acres of forest takes up," Sullivan, an assistant professor in the Department of Natural Resources and Environmental Science, said. "We want to quantify above ground and below ground carbon stocks in meadows and know if an increase in aboveground carbon associated with trees growing in a former meadow is offset by much greater losses of soil carbon below ground." While the research area stretches much of the length of the Sierra Nevada from Mt. Lassen to Bishop, Calif., this recent research was performed in four meadows in the Truckee River watershed and involved about 75 volunteer participants from northern California and the Reno area, including a student organization at Hug High School in Reno; students in a University of Nevada, Reno English composition class on "Science and Society;" and students from the University of California, Berkeley Forestry Camp. The project focused on measuring the carbon stored in plants and determining if vegetation is an important indicator of the amount of carbon below ground. Sullivan, students in his lab, and the team of citizen scientists quantified the amount of carbon in trees in the nearby forests as well as where trees and shrubs are establishing within the meadows. They measured the diameter and height of trees and shrubs and clipped small plots of grasses to measure the amount of carbon in the vegetation. Involving citizen scientists allowed the University research team to vastly increase their sampling capacity and address scientific questions at larger scales. "We got weeks of work done in a couple of days thanks to our citizen scientist volunteers," Sullivan said. "It's a valuable program, and we're grateful for the Earthwatch collaboration. The Earthwatch Institute typically supports international research, so it's exciting to lead a research campaign that allows volunteers to learn about their own back yards and be back at work on Monday morning." The research was designed to increase scientific literacy of area students and residents, engage citizens in the scientific method, and improve understanding of how carbon stocks in meadow vegetation change from the forest to the stream. "The carbon builds up in the cold, wet meadow soil in the Sierra over thousands of years," Sullivan said. "But disturbed meadows may be a net source of carbon dioxide and other greenhouse gases, like nitrous oxide and methane, to the atmosphere. We have to understand what is happening in degraded meadows, so we can quantify any positive effects of restoration." "Restoring meadows can have many benefits, but we want to know if it can also increase the soil C sink by making the meadows wet again" Sullivan said. "Because meadows have been restored in the Sierra for the past 15 years, we can measure how carbon stocks change over time and where in the meadow the changes happen and what the levels are. We want to know if meadow restoration could increase the ability of meadow soil to retain and store carbon." The team aims to develop a model that can predict how much carbon is sequestered in a meadow. The data may be used by the State of California Air Resources Board to sell carbon credits through their Cap and Trade program that strives to reduce greenhouse gas emissions in California to 1990 levels by 2020. If the research shows that meadow restoration locks up carbon, the program could allow landowners who restore a meadow area to sell carbon credits - potentially offsetting costs of restoration. "In addition to Earthwatch, we are working with partners at Plumas Corporation, CalTrout, the Truckee River Watershed Council - and many more - to address these questions about Sierra meadows," Sullivan said. "We look forward to even more citizen scientists working with us in the coming summers to help measure carbon in meadows while learning about these dynamic ecosystems." The volunteers found the work rewarding and beneficial. "The collaboration between Earthwatch and the University of Nevada, Reno represented an unprecedented opportunity for the students to not only learn about meadows, but to interact with graduate and staff researchers," John Arsenault, teacher at Hug High who brought some of his students into the program, said. "The discussion, questions and exploration that happened was experiential and real." The project will be presented by one of Sullivan's graduate students, Cody Reed, at the American Geophysical Union Fall Meeting on Tuesday, Dec. 13. Her poster presentation, titled "Anthropogenic disturbance of montane meadows may cause substantial loss of soil carbon to the atmosphere," will feature the two meadows studied this fall with the Earthwatch citizen scientists as well as an additional meadow Sullivan's team has studied. Studying the greenhouse gases produced and consumed by soils is one of Sullivan's primary research interests. He is an assistant professor in the College of Agriculture, Biotechnology and Natural Resources and a member of the University's Global Water Center. To learn more about Earthwatch and their international research programs, visit Earthwatch.org, and to learn more about soils research at the University of Nevada, Reno visit SullivanLab.weebly.com.
News Article | November 11, 2016
Imagine being in your garden and stumbling on an enormous earthworm that measures about as long as a standard bowling pin is tall, and that weighs about the same as a small chocolate bar. The encounter, while likely startling, ended up being a record-setting encounter for a man in the United Kingdom, after he came across what has now been crowned the earthworm that is not only the longest ever found in the U.K., but also the heaviest known wild worm in the world. The earthworm was named Dave by the stepson of the man who discovered it. It was then sent to the Natural History Museum in London for evaluation, where museum experts determined that Dave is a lob worm, Lumbricus terrestris. The worm measures nearly 16 inches (40 centimeters) long and weighs almost 1 ounce (26 grams), which sets new records in both categories. In fact, Dave nearly doubled the previous heavyweight record holder: a worm found in Scotland that weighed just 0.5 ounces (15 grams). [No Creepy Crawlies Here: Gallery of the Cutest Bugs] Emma Sherlock, senior curator of free-living worms at the Natural History Museum and chair of the Earthworm Society of Britain, said that Dave's size is astounding. "I was bowled over by the size of this worm when I opened the plastic box they sent it in," Sherlock said in a statement. "Not only is it really long, it is almost twice as heavy as any other wild earthworm ever seen, weighing the same as a small chocolate bar." Dave's size is particularly impressive for a worm in the wild, according to experts. With plenty of natural predators and other threats, the Natural History Museum noted that earthworms don't typically survive long enough in the wild to reach such a record size. Sherlock said that the vegetable plot in which Dave was found must have been "incredibly fertile and well-drained." Earthworms play a key role in keeping soils healthy. According to Earthworm Watch — a survey of earthworms and soil quality that is run by the museum and the Earthwatch Institute, in association with the Earthworm Society of Britain — earthworms improve soil fertility and the ability for soil to store carbon by mixing in dead plant material. As part of continued research into earthworms, the museum routinely monitors worms, identifying them and releasing them back into the wild. However, a few are kept at the museum as a record of the population, especially if they are particularly unusual. Given Dave's significant size, the worm was anesthetized by museum scientists to be preserved, the institution said. Dave will now join a scientific collection of 80 million specimens at the Natural History Museum. "This may seem sad, but by being part of the scientific collection this earthworm will have a legacy that lasts beyond all of our lifetimes, helping scientists today and tomorrow to understand and protect this species and its environment," Sherlock said.
News Article | November 11, 2015
Molecular biologist Nina Dudnik was studying rice in Côte d'Ivoire when she realized the logistical challenge of doing research in the developing world. “I was trying to conduct research in a country an ocean away from where the equipment manufacturers and reagent suppliers were,” she says. “We had to wait months to get them.” When she returned to start her PhD course at Harvard University in Cambridge, Massachusetts, she led a group of fellow students to collect surplus equipment and supplies for labs in need in developing countries. Eventually, her volunteer work became a non-profit business, and in 2007, she founded Seeding Labs in Boston, Massachusetts. The firm provides scientific training and refurbished equipment to research institutions. “We work with a large network of corporations and research institutions that donate their surplus equipment to us, and we distribute it to the labs that need it,” Dudnik says. Since its inception Seeding has partnered with scientists in 22 nations, and in 2015 it was hailed by Fast Company magazine as one of the world's top ten most innovative non-profit organizations. Dudnik expects to ship equipment to about 15 university departments next year. In support of her goal, last year she won a US$3-million grant from the US Agency for International Development. She has four full-time employees and next year expects to hire a fifth. The non-profit sector appealed to Dudnik because of its vast potential for helping others. “This is a problem with great social impact,” she says of labs in developing nations that struggle with insufficient and worn-out equipment and resources. “My desire to solve it has nothing to do with becoming rich and famous.” This objective represents the biggest difference between for-profit and non-profit businesses: non-profit groups are driven by their mission rather than by the need to bolster the bottom line. “They're interested in solving problems,” says Joanne Kamens, who is executive director at Addgene, a non-profit organization in Cambridge, Massachusetts, that operates a plasmid repository for the research community. For that reason, scientists often thrive in non-profit organizations, Kamens says, because they value knowledge and solutions. Roles for scientists in the non-profit sector are as diverse as the types of organizations that exist in it. Scientists might, for example, do bench research, manage large-scale community projects, work with disease-advocacy groups or become science communicators at professional societies. Finding the type of non-profit that dovetails with one's interests requires an understanding of how the organizations operate and the opportunities that they offer. Networking contacts and online job sites, such as Idealist (www.idealist.org), can help to provide this information, says Dudnik. She recommends talking with a broad cross-section of employees in the sector to get a clear idea of their organization's mission and available jobs, internships and volunteer posts. Scientists are increasingly deciding that they are a good fit with the sector: the number of PhD holders from the life and physical sciences who enter it is rising, according to the US National Science Foundation's biennial Survey of Doctoral Recipients (go.nature.com/hkzsmg). In 2003, 5% of science-doctorate holders were working in the non-profit sector; the rate increased to about 7% by 2013. Employment opportunities in the sector are also on the increase, according to a survey this year from Nonprofit HR, a US human-resources group based in Washington DC that serves the sector. The survey found that about half of non-profit organizations in the United States and Canada planned to create new positions this year. Those who hope to land a professional post at a non-profit business should have volunteer or internship experience, both to provide a flavour of working in the sector and to deflect possible scepticism from potential co-workers. Some non-scientist employees in the sector may perceive a researcher as someone who can only pipette or peer into a microscope. “Having any kind of volunteering or interning experience is really, really vital,” says Dudnik. “It will demonstrate that you are capable of more than research and that you have a passion for helping others.” Scientists in non-profit organizations often find themselves becoming part of a local community. Residents of Assen, the Netherlands, needed help to improve safety for cyclists along a canal at night, so the city turned to its regional science shop. Such 'shops' are non-profit groups that are usually linked to a university and provide research in response to local concerns. With help from the municipal government and volunteers, science-shop researchers found that green lights illuminated cyclists' paths without unduly disturbing the area's wildlife. “It was a cooperation between different stakeholders that are involved in this specific problem,” says Norbert Steinhaus, coordinator and international contact for Living Knowledge, which coordinates the international science-shop network. Many scientists who work at non-profit groups enjoy a latitude that would be unlikely in the for-profit sector. Aimee Dudley, a lab group leader at the non-profit Pacific Northwest Diabetes Research Institute in Seattle, Washington, says that she has considerable freedom in her research programme. “I consider myself the head of my own small business,” she says. “I determine the direction of the lab, get funding, make sure it has the money to pay people and do experiments.” Dudley maintains an affiliate faculty post in the University of Washington's genome-sciences department, which links her with colleagues and their research. It also provides her with access to the university's library and subscriptions, as well as to graduate students, who can perform their thesis research work in her lab. “I enjoy teaching and supervising in the lab, and think it's important to help the next generation of researchers,” she says. For her, hosting students and providing on-site training is another aspect of her flexibility. “If I wasn't interested in having students, I wouldn't,” she says. Autonomy has also been valuable to Cristina Eisenberg, a lead scientist at the Boston-based Earthwatch Institute. In the past year, she has travelled twice to the Pacaya-Samiria National Reserve in Peru's Amazonian region, where she oversees Earthwatch's projects, including a decade-long study of climate-change effects in the Amazon. “This position enables me to have far more impact on science and sustainability than if I was at a university teaching classes,” she says. Joseph Jerry is science director at the non-profit Pioneer Valley Life Sciences Institute (PVSLI) in Springfield, Massachusetts, as well as a faculty member at the University of Massachusetts Amherst. This means that he can augment his basic research into breast cancer at the university with more-translational research at PVSLI, where he says he gets to work closely with patients and advocates. The opportunity to interact directly with clinical patients has been an eye-opening experience for Jerry, who admits that as a scientist, he has been most comfortable in the lab. “I don't consider myself a people person, but working with patients is a wonderful experience,” he says. “I've learned a lot about how to communicate better.” Yet for all of their upsides, non-profit organizations are hardly perfect; like any other business, they are vulnerable to a faltering economy. Historically, they have depended on a philanthropic business model: supported by hefty and regular donations, they provided a service or product for which consumers or clients did not pay. But that model has weakened along with the global economy, and non-profits are seeking other ways to secure funds. Seeding Labs, for example, no longer depends entirely on philanthropy — it charges clients a fee to cover part of the cost of doing business. The fee also increases the likelihood that Seeding's services will be more highly valued, Dudnik says. Still, notes Kamens, in a shifting economic landscape, researchers may be especially desirable for non-profit posts that require fundraising because they typically have substantial experience of writing grants. “It's very hard to find people who are good at development work,” she says. Ultimately, researchers who work at non-profit groups become part of a community of people who care deeply about the organization's goals. That was the reason that Eisenberg left her academic post for Earthwatch in the first place. For her, working at a non-profit meant more than spending time in the jungle or the lab. “We work together,” she says, “to advance our mission — science”.
News Article | November 3, 2016
Citizen scientists are already providing large amounts of data for monitoring biodiversity, but they could do much more, according to a new study published in the journal Biological Conservation, which suggests that citizen science has the potential to contribute much more to regional and global assessments of biodiversity. Citizen scientists are regular people who provide data or input to science, for example by monitoring species in their community or examining satellite imagery for evidence of deforestation or land use change. "Citizen scientists are already contributing enormously to environmental science," says IIASA researcher Linda See. "For example, a huge amount of species occurrence data is provided by members of the interested public. The question we addressed was, where are citizens contributing and where are they not, and how can we draw on this phenomenon to help fill the gaps in science?" The new article looks at international conventions on biodiversity and endangered species, and the indicators that are needed to track biodiversity on a global scale, known as Essential Biodiversity Variables (EBVs). It examines the areas where citizen scientists already contribute, those where they do not, and what areas could benefit from expansion of citizen science efforts. "Biodiversity is essential to our well-being on planet Earth, providing core ecosystem services such as pollination, pest control, and buffering of extreme events. With many continuing pressures on land, biodiversity is constantly threatened so there is a need to better monitor this valuable resource globally. But there are many big data gaps in biodiversity, often in those places where the need is greatest. Citizen scientists can help to fill some of these gaps, both geographically and taxonomically," says Mark Chandler, Director of Research Initiatives at the Earthwatch Institute, who led the study. The study represents the most comprehensive survey to date of citizen science, including community-based monitoring. It finds that citizen scientists are one of the main sources of data on species occurrence, in particular for birds and especially in North America and Europe. The researchers argue that such programs could be strategically expanded in order to provide more data on other indicators and from countries outside North America and Europe. The researchers also found that while a lot of citizen-generated data already exists, less than 10% finds its way into global biodiversity monitoring. This bottleneck comes from a lack of resources, issues of interoperability, and a need for data repositories. Although the Global Biodiversity Information Facility (GBIF) has been a great success for curating global species occurrence data, this represents only 1 out of 22 EBVs. The researchers say that it is important to establish similar repositories for other EBVs. One positive finding is that citizen science complements other forms of monitoring such as remote sensing. Efforts are now underway to look at combining efforts to get a more complete assessment of what is happening to biodiversity. Chandler M, See L, Copas K, Bonde AMZ, Lopez BC et al (2016). Contribution of citizen science towards international biodiversity monitoring. Biological Conservation doi:10.1016/j.biocon.2016.09.004 The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, Europe, and Oceania. http://www. Earthwatch Institute is an international nonprofit organization that connects citizens with scientists to improve the health and sustainability of the planet. Since its founding in 1971, Earthwatch has empowered nearly 100,000 volunteers from all walks of life to join leading scientists on field research expeditions that tackle critical environmental challenges around the globe - from climate change to ocean health, human-wildlife conflict, and more. Earthwatch works with all sectors of society, from corporations to teachers, students, community leaders, zoos and aquaria, and more. earthwatch.org
News Article | November 3, 2016
Citizen scientists are already providing large amounts of data for monitoring biodiversity, but they could do much more, according to a new study published in the journal Biological Conservation, which suggests that citizen science has the potential to contribute much more to regional and global assessments of biodiversity. Citizen scientists are regular people who provide data or input to science, for example by monitoring species in their community or examining satellite imagery for evidence of deforestation or land use change. "Citizen scientists are already contributing enormously to environmental science," says IIASA researcher Linda See. "For example, a huge amount of species occurrence data is provided by members of the interested public. The question we addressed was, where are citizens contributing and where are they not, and how can we draw on this phenomenon to help fill the gaps in science?" The new article looks at international conventions on biodiversity and endangered species, and the indicators that are needed to track biodiversity on a global scale, known as Essential Biodiversity Variables (EBVs). It examines the areas where citizen scientists already contribute, those where they do not, and what areas could benefit from expansion of citizen science efforts. "Biodiversity is essential to our well-being on planet Earth, providing core ecosystem services such as pollination, pest control, and buffering of extreme events. With many continuing pressures on land, biodiversity is constantly threatened so there is a need to better monitor this valuable resource globally. But there are many big data gaps in biodiversity, often in those places where the need is greatest. Citizen scientists can help to fill some of these gaps, both geographically and taxonomically," says Mark Chandler, Director of Research Initiatives at the Earthwatch Institute, who led the study. The study represents the most comprehensive survey to date of citizen science, including community-based monitoring. It finds that citizen scientists are one of the main sources of data on species occurrence, in particular for birds and especially in North America and Europe. The researchers argue that such programs could be strategically expanded in order to provide more data on other indicators and from countries outside North America and Europe. The researchers also found that while a lot of citizen-generated data already exists, less than 10% finds its way into global biodiversity monitoring. This bottleneck comes from a lack of resources, issues of interoperability, and a need for data repositories. Although the Global Biodiversity Information Facility (GBIF) has been a great success for curating global species occurrence data, this represents only 1 out of 22 EBVs. The researchers say that it is important to establish similar repositories for other EBVs. One positive finding is that citizen science complements other forms of monitoring such as remote sensing. Efforts are now underway to look at combining efforts to get a more complete assessment of what is happening to biodiversity. Explore further: Hacking the environment: bringing biodiversity hardware into the open More information: Mark Chandler et al, Contribution of citizen science towards international biodiversity monitoring, Biological Conservation (2016). DOI: 10.1016/j.biocon.2016.09.004
Bebber D.P.,Earthwatch Institute |
Watkinson S.C.,University of Oxford |
Boddy L.,University of Cardiff |
Darrah P.R.,University of Oxford
Oecologia | Year: 2011
Anthropogenic nitrogen (N) deposition affects many natural processes, including forest litter decomposition. Saprotrophic fungi are the only organisms capable of completely decomposing lignocellulosic (woody) litter in temperate ecosystems, and therefore the responses of fungi to N deposition are critical in understanding the effects of global change on the forest carbon cycle. Plant litter decomposition under elevated N has been intensively studied, with varying results. The complexity of forest floor biota and variability in litter quality have obscured N-elevation effects on decomposers. Field experiments often utilize standardized substrates and N-levels, but few studies have controlled the decay organisms. Decomposition of beech (Fagus sylvatica) blocks inoculated with two cord-forming basidiomycete fungi, Hypholoma fasciculare and Phanerochaete velutina, was compared experimentally under realistic levels of simulated N deposition at Wytham Wood, Oxfordshire, UK. Mass loss was greater with P. velutina than with H. fasciculare, and with N treatment than in the control. Decomposition was accompanied by growth of the fungal mycelium and increasing N concentration in the remaining wood. We attribute the N effect on wood decay to the response of cord-forming wood decay fungi to N availability. Previous studies demonstrated the capacity of these fungi to scavenge and import N to decaying wood via a translocating network of mycelium. This study shows that small increases in N availability can increase wood decomposition by these organisms. Dead wood is an important carbon store and habitat. The responses of wood decomposers to anthropogenic N deposition should be considered in models of forest carbon dynamics. © 2011 Springer-Verlag.
Crockatt M.E.,Earthwatch Institute |
Crockatt M.E.,University of Oxford |
Bebber D.P.,University of Exeter
Global Change Biology | Year: 2015
Forests around the world are increasingly fragmented, and edge effects on forest microclimates have the potential to affect ecosystem functions such as carbon and nutrient cycling. Edges tend to be drier and warmer due to the effects of insolation, wind, and evapotranspiration and these gradients can penetrate hundreds of metres into the forest. Litter decomposition is a key component of the carbon cycle, which is largely controlled by saprotrophic fungi that respond to variation in temperature and moisture. However, the impact of forest fragmentation on litter decay is poorly understood. Here, we investigate edge effects on the decay of wood in a temperate forest using an experimental approach, whereby mass loss in wood blocks placed along 100 m transects from the forest edge to core was monitored over 2 years. Decomposition rate increased with distance from the edge, and was correlated with increasing humidity and moisture content of the decaying wood, such that the decay constant at 100 m was nearly twice that at the edge. Mean air temperature decreased slightly with distance from the edge. The variation in decay constant due to edge effects was larger than that expected from any reasonable estimates of climatic variation, based on a published regional model. We modelled the influence of edge effects on the decay constant at the landscape scale using functions for forest area within different distances from edge across the UK. We found that taking edge effects into account would decrease the decay rate by nearly one quarter, compared with estimates that assumed no edge effect. © 2014 John Wiley & Sons Ltd.
Crockatt M.E.,Earthwatch Institute
Fungal Biology Reviews | Year: 2012
Fungi are vital within forest ecosystems through their mycorrhizal relationships with trees, and as the main agents of wood decomposition and thus carbon and nutrient cycling. Globally, forests are becoming increasingly fragmented, creating forest patches that are isolated, reduced in area, and exposed at edges. Edges are often ecologically distinct from the forest interior due to their exposure to the matrix habitat. This exposure can result in altered microclimatic conditions and flows of biotic and abiotic materials such as spores or inorganic nitrogen, respectively.Although fungi are known to be affected by microclimate and nitrogen deposition, knowledge of forest edge effects on fungi is extremely limited; however, a consideration of the factors known to regulate fungal activity in combination with known biotic and abiotic edge effects implies that forest edges are likely to strongly influence fungi. These include responses of fungi to the altered microclimate and nitrogen levels at forest edges, at both the individual and community level; interactions with plants and animals that have been influenced by edges; above-belowground feedback between mycorrhizal fungi and host trees. The small body of existing research focuses on fruit body presence and distribution; fungal biomass and community composition in soil have been touched upon. Positive, negative and neutral edge responses have been found, the majority of studies finding a significant effect on some of the parameters measured. Generally, abundance of fruit bodies and biomass in the soil is lower at the forest edge.Understanding how fungi respond to edges is essential to a more complete knowledge of carbon and nitrogen cycling in forest edges, influence of mycorrhizal species on vegetation, and conservation of rare fungi. As edges become increasingly dominant landscape features it is vital to investigate processes within them, to understand ecosystem function at a landscape scale. © 2012 The British Mycological Society.