Spasojevic M.J.,University of California Irvine |
Spasojevic M.J.,University of Washington |
Copeland S.,University of California Davis |
Suding K.N.,University of California Berkeley
Ecography | Year: 2014
The metacommunity concept, describing how local and regional scale processes interact to structure communities, has been successfully applied to patterns of taxonomic diversity. Functional diversity has proved useful for understanding local scale processes, but has less often been applied to understanding regional scale processes. Here, we explore functional diversity patterns within a metacommunity context to help elucidate how local and regional scale processes influence community assembly. We detail how each of the four metacommunity perspectives (species sorting, mass effects, patch dynamics, neutral) predict different patterns of functional beta- and alpha-diversity and spatial structure along two key gradients: dispersal limitation and environmental conditions. We then apply this conceptual model to a case study from alpine tundra plant communities. We sampled species composition in 17 'sky islands' of alpine tundra in the Colorado Rocky Mountains, USA that differed in geographic isolation and area (key factors related to dispersal limitation) and temperature and elevation (key environmental factors). We quantified functional diversity in each site based on specific leaf area, leaf area, stomatal conductance, plant height and chlorophyll content. We found that colder high elevation sites were functionally more similar to each other (decreased functional beta-diversity) and had lower functional alpha-diversity. Geographic isolation and area did not influence functional beta- or alpha-diversity. These results suggest a strong role for environmental conditions structuring alpine plant communities, patterns consistent with the species sorting metacommunity perspective. Incorporating functional diversity into metacommunity theory can help elucidate how local and regional factors structure communities and provide a framework for observationally examining the role of metacommunity dynamics in systems where experimental approaches are less tractable. © 2014 The Authors. Source
Africa is home to some of the most diverse ecosystems and last pristine natural areas left in the world — but it’s a changing landscape. Growing populations and rapid development are reshaping the continent, and while this can be good news for humans, it often comes at the expense of Africa’s wild animals and habitats. Now, researchers have investigated one aspect of development on the African continent: “development corridors,” or swaths of developed land usually centered on roads or railroads. The new paper, which was published Wednesday in the journal Current Biology, evaluates the agricultural benefits of these corridors versus their environmental importance. Roads, railroads and other forms of development can provide economic services by linking urban areas or providing better transportation to and from industrial sites, such as mines. But given Africa’s rapidly growing population and growing concerns over food security, the need for better roads is often heavily supported by the boost they provide to the agricultural industry in the form of improved transportation and better access to urban markets. Research has also shown that they can negatively impact the environment by breaking up natural habitats and drawing more humans into the area. That means economic and social interests are sometimes at odds with environmental and conservation interests. “Africa has large areas of land that are underperforming,” said the paper’s lead author, William Laurance, director of the Centre for Tropical Environmental and Sustainability Studies at James Cook University in Australia. “It also has very important wildlife and biodiversity and natural resources. If you put all that together, Africa is kind of a ticking time bomb in terms of potential conflict.” Laurance and his colleagues decided to evaluate the impact of 33 development corridors — all centered on roads or railroads — on the continent, some of which already exist and some of which had only been proposed. Put together, the planned and existing corridors would total more than 53,000 kilometers (or about 33,000 miles) in length and crisscross much of the continent, cutting through forests, savannas and shrublands. The research was inspired by a 2014 study that Laurance also co-authored, which assessed “where, ideally, one would build roads and where one would not build roads across the entire planet Earth,” Laurance said, by looking at the costs and benefits of the development. Afterwards, Laurance and his colleagues decided to narrow down their research. “The reason that we focused on Africa after doing a global analysis [is that] our sense is that Africa is facing more severe challenges than anywhere else,” Laurance said. And, in fact, the paper is “extremely timely because numerous large projects are being planned across the continent of Africa,” said Tim Caro, a professor of wildlife biology at the University of California Davis and fellow at the Institute for Advanced Study in Berlin, in an e-mail to The Post. (Caro was not involved with this paper). “These projects are well known in government circles of the nations involved and to donor agencies but are less well known to the general public outside the continent.” For the new paper, the researchers examined the areas occupied by (or proposed to be occupied by) the development corridors — including a swath of land 25 kilometers wide on either side of the road or railroad — to determine how dense the human population was and how high their environmental values were, based on factors such as biodiversity and the number of threatened species found in the region. The 25-kilometer buffer zone on either side was meant to take into account the fact that roads and railroads can affect wildlife and their habitats for miles around by drawing humans into the area and increasing the likelihood of further development, more hunting and poaching, noise, fires and other disturbances. The researchers then used these factors to evaluate each area’s conservation priority — high priority was given to areas with low human populations and high environmental value. In general, they found that forests and savanna woodlands had higher conservation priority than shrubland habitats, with especially important areas found in the forests of the greater Congo Basin and the savannas of East Africa. The researchers also evaluated each corridor’s potential agricultural benefits — that is, the potential for each corridor’s improved transportation to increase agricultural output. In general, the researchers found that potential benefits were higher in savanna woodlands than other types of habitats — and they also concluded that the potential benefits of the proposed corridors were, on average, lower than those of the corridors that already existed. When they put all their findings together, the researchers were able to divide the 33 corridors into three groups: five “promising” corridors, which had relatively low conservation priority and a high potential to benefit agriculture; 22 “marginal” corridors, which had either both high conservation priority and high potential agricultural benefits, or low values for both; and six “inadvisable” corridors, which had high conservation priority and low potential agricultural benefits. “One of the real concerns is that a number of these projects would penetrate way out into sparsely populated areas of Africa that are still largely wild, or that have a lot of natural value, and we think would really bring a tsunami of change to the African continent,” Laurance said. “A number of the projects are probably not a good idea at all.” Indeed, as far as the planned corridors are concerned, he said policymakers should consider canceling some of them altogether. And others, if they do proceed, “need to be looked at really carefully,” he added. Complicating the mix is the fact that the corridors also cut through (or would, if they were completed) a number of protected areas on the African continent. Just the roads and railways considered in this study would bisect more than 400 protected areas. And if you factor in the 25-kilometer buffer zone on either side of the corridors, which the researchers considered in their analyses, these corridors would affect more than 2,000 protected areas. That news can be taken in several ways. On the one hand, it means that some corridors are likely to seriously degrade some already-protected areas (which are usually protected because of their environmental significance). “This suggests that a number of the continent’s famous protected areas for large mammals could be in jeopardy within our lifetime,” said Caro in his e-mail. On the other hand, Laurance noted that it might be beneficial from a conservation standpoint to preemptively establish new protected areas in regions that are likely to be developed in the future. If a corridor is going to be developed anyway, making the region a protected area — for instance, prohibiting other forms of development or limiting hunting in the region — could help soften the environmental impact of the corridor, he said. But there are other considerations to think about, too. While this study only evaluated the corridors for their conservation priority and their agricultural benefits, corridors can provide other boons in the eyes of national governments. In particular, roads and railroads are often built to facilitate mining, which policymakers often see as a major potential economic boost — so they may not always be swayed by arguments that center on agriculture. For his part, Laurance has also written about the environmental impacts of mining in Africa and feels that the “mining frenzy” also carries the risk that its economic benefits won’t be distributed throughout society in an equitable way. However, others have argued that mining is delivering a much-needed economic boost to nations across the continent. And on the environmental side, there are other factors to take into account when considering the impact of roads, which were not included in this study — for instance, the increased carbon footprint associated with heavier traffic. In any case, Laurance recommends a case-by-case evaluation of every proposed corridor moving forward. “What one needs to do is really drill down and start looking very specifically at using finer-scale information — the local habitats, local environments, local costs and benefits,” he said. These kinds of evaluations have been conducted only sporadically in the past, he asserted, and “there’s been no systematic attempt to try and assess these different projects.” And Caro seconded this sentiment in his e-mail, adding, “What is needed in addition to such large scale analyses are country-by-country reports that these are sent to known officials in government offices in hard and soft copy, and to the international agencies that are paying for these development projects.” The continent’s environmental interests will likely continue to be challenged as social and economic pressures build, along with rising populations and increasing concerns over food security and economic stability. “I think Africa is going to change probably more dramatically [in the future],” Laurance said. So as the continent continues to evolve, these types of analyses will become more and more important — if there’s to be any hope for Earth’s dwindling wildlife and their natural habitats.
Around the world, the animals that pollinate our food crops — over 20,000 species of bees, butterflies, bats and many others — are the subject of growing attention. An increasing number of pollinator species are thought to be in decline, threatened by a variety of mostly human pressures, and their struggles could pose significant risks for global food security and public health. Until now, most assessments of pollinator health have been conducted on a regional basis, focusing on certain countries or parts of the world. But this week, a United Nations organization has released the first-ever global assessment of pollinators, highlighting their importance for worldwide food and nutrition, describing the threats they currently face and outlining strategies to protect them. The report, which was released Friday by the U.N.’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), has been in the works since the summer of 2014. The research team consisted of more than 70 experts, who drew on the most up-to-date global pollinator science, as well as local and indigenous knowledge, to complete the assessment. The report includes four overarching findings, said Simon Potts, deputy director of the Center for Agri-Environmental Research at Reading University, during a Friday press briefing. First, there are well-documented declines in pollinators, both wild and managed, throughout the world. Second, these pollinators provide society with a wide range of benefits. Third, they are threatened by a variety of factors. And fourth — and most importantly — there are still opportunities to protect them. The health of pollinator populations is intrinsically tied up with global food security, the IPBES assessment notes. Altogether, nearly 90 percent of all flowering plants on Earth depend on animal pollination, and that includes about 75 percent of the world’s food crops. [How humanity’s ancient past explains why we’re still damaging the environment today] Keeping agricultural production high enough to feed the world’s ballooning human populations will depend in a big way on the insects and other animals that help them reproduce. The assessment reports that in the past 50 years alone, the volume of agricultural production that depends on animal pollination has increased by about 300 percent. “Our nutritional security is intimately linked to pollinators, with many of our vitamins derived from pollinated crops,” Potts said. “So there is this kind of link between pollinators, crops and human diets and ultimately health.” Some of the most widely enjoyed crops that heavily depend on animal pollination include apples, cocoa beans, coffee and almonds. And pollinators’ importance to agriculture means there’s a big economic factor to consider there as well. “The global market value linked to pollinators is huge,” Potts noted. The assessment finds that anywhere from $235 billion to $577 billion worth of global food production every year relies on animal pollination. Additionally, many pollinator species have immense social and cultural value, Vera Imperatriz-Fonseca, co-chair of the assessment and an ecology professor at the University of Sao Paulo in Brazil, said at the briefing. She pointed out that many are “a source of inspiration for all of us in art, music, literature, religion and technology.” So there are clear reasons to care about the fate of the world’s pollinators. The problem is that in many places, they aren’t doing so well. Using data from the International Union for Conservation of Nature’s Red List of Threatened Species, the IPBES assessment points out that more than 16 percent of vertebrate pollinators on Earth — that’s mainly bats and birds — are threatened with extinction. Insects are a little harder to assess because there tends to be less global data about them. But regional studies have shown widespread declines throughout many parts of the world, especially among bees and butterflies. “Using internationally accepted IUCN assessment criteria, there are some national red lists for bees which often have more than 40 percent of the species listed as threatened,” Potts said. He also added that there’s been only one continental assessment conducted, which studied bees and butterflies in Europe and found that 9 percent were threatened. Even this number is likely an underestimate, he added, given that approximately half the bee species on the continent could not be assessed due to a lack of data. The declines are a concern for both wild pollinators and managed ones, which are kept by humans, the researchers are careful to note. Honeybees are the most common managed pollinators. And while overall the number of honeybee hives throughout the world has doubled in the last 50 years, certain regions — most notably Europe and North America — have experienced significant declines as a result of colony collapse disorder. What’s threatening the pollinators — and how can we help them? According to the assessment, there are a wide variety of factors affecting pollinators throughout the world, and it would be difficult to pinpoint one primary source of all the trouble. Habitat destruction and degradation is one important source. Some species of pollinators can visit just about any type of plant they want — but others are much more specialized, and only feed on certain species. So having a high diversity of plants in any given area is important for attracting many different types of pollinators. Developing the land and cutting down on the natural plant diversity in an area can be a big problem. Intensive agriculture, which focuses on only a few crops at a time, can be a contributor to this issue. And the use of pesticides has demonstrated harmful effects as well — an issue that’s recently come to the forefront of national attention in the United States. The Obama administration’s National Strategy to Promote the Health of Honey Bees and Other Pollinators, released by the White House last year, called for better scrutiny of the effects of pesticides on pollinating insects. And last month, the Environmental Protection Agency released the first in a series of preliminary risk assessments of insecticides thought to be harmful to bees. The U.N.’s assessment notes that the effects of pesticides depend on the type of chemical being used, the amount in which it’s applied and the type of pollinator that’s been exposed. However, the assessment does report that research has found a variety of lethal and nonlethal (but still negative) consequences of pesticide exposure in insect pollinators, mainly bees. During Friday’s press briefing, the authors were quick to clarify that the report is not meant to be taken as a blanket condemnation of pesticide use. “We don’t provide recommendations,” Potts said. “Just really high-quality evidence based on what the available data says.” Other factors thought to be affecting pollinators include disease and the influence of invasive species, which can compete with native species for resources. And climate change is becoming a growing concern, as well. Many species have already been affected by the changing climate, said Jeremy Kerr, a biology professor at the University of Ottawa, who was not an author on the new assessment. Last year, Kerr was the lead author on a study published in Science which found that bumblebees in both North America and Europe have been shifting their ranges in response to climate change. [We’ve reached the point where we need these bizarre technologies to stop climate change] This kind of reaction is a concern because there’s a possibility that, over time, pollinators could shift their ranges out of reach of the plants they usually pollinate. And this is just one effect we’ll likely continue to see in the future. “One of the other things that’s certainly an issue here in terms of individual species and the direct effect of climate on species … is the timing they have, or the phenology of these species — when they come out, when they do the things that they do,” Kerr said. Climate change can cause some species to emerge at different times of the year than they used to, for instance, or reproduce at different times. These kinds of changes could disrupt their seasonal interactions with the plants they pollinate. With so many factors threatening the world’s pollinators, the looming question is whether anything can be done to save them. According to the new assessment, there are actually a lot of opportunities on this front. Protecting natural areas and diversifying the landscape are obvious steps. The assessment suggests restoring native vegetation, planting flower corridors and trying to keep natural areas connected to one another as much as possible. “Hospitable landscapes are ones where there are suitable nesting habitats for diverse pollinator species, and where consistent forage resources are accessible (within the flight range) of the bees throughout their flight seasons,” Neal Williams, an entomologist at the University of California Davis (who was also not an author on the new assessment), said by email. The assessment also recommends more diverse and sustainable forms of agriculture — for example, utilizing organic farming practices, conducting crop rotations and allowing diverse communities of plants to grow alongside traditional farmland in order to attract and maintain pollinator populations. More in-depth research will be necessary for a better understanding of the specific effects of individual pesticides, and governments may also consider coming up with strategies to reduce their pesticide use and develop more diverse pest management techniques, the assessment suggests. And taking steps to minimize the introduction of invasive species, combat the spread of disease among pollinators and mitigate climate change are all crucial, as well. The biggest takeaway is that there are a huge variety of threats facing the world’s pollinators, and so proportional action must be taken to address each of them as soon as possible. “The question for us as a society really, not just a science community, is can we walk and chew gum at the same time in terms of dealing with conservation solutions,” said Kerr. “Are we really only capable of doing one thing at a time, or can we manage habitats better than we do now, can we control our pesticide use so we’re just a little more careful than we are now?” The answer remains to be seen, and will likely depend on the coordinated actions of individual governments. But there’s much to be optimistic about, according to the assessment’s authors. The report was agreed upon by the more than 100 countries belonging to IPBES, which demonstrates an international concern for the issue, they pointed out at Friday’s briefing. The role of IPBES, and its report, is to strengthen the dialogue between the scientific community and policymakers, said IPBES chair Zakri Abdul Hamid. “We wanted the government to be moved to take action, and that’s what it’s all about,” he said. Top scientists insist global warming really did slow down in the 2000s A shocking one third of Americans believe this Zika conspiracy theory Your home water heater may soon double as a battery For more, you can sign up for our weekly newsletter here, and follow us on Twitter here.
News Article | July 29, 2016
Ticked Off! Here's What You Need To Know About Lyme Disease Breeders of the English bulldog are facing concerns about the way "extreme" physical changes have affected the health of the breed. And the only way to reverse these unhealthy changes now would be to crossbreed the English bulldog and introduce new bloodlines, researchers suggest. In the study presented in Canine Genetics and Epidemiology, the researchers examined whether the English bulldog as a breed exhibits sufficient "genetic diversity" in order to rectify phenotypic and genotypic defects. Some of the physical and genetic attributes of the English bulldog have been linked to poor health. The breed is known to suffer from reproductive issues, such as the presence of a narrow pelvis in females, which makes birthing difficult. Other physical traits, such as the dog's short snout, have also made breathing difficult for the canine, and this has been one of the animal's leading cause of death. Genetic diversity may, however, help to rid the gene pool of mutations and bring about additional phenotypic changes to the breed, such as changes to the dog's body structure or coat. Selective breeding over the centuries has led to inbreeding which, in turn, has resulted in "very low genetic diversity" among English bulldogs, the study authors note. This low diversity, or limited genetic stock, is attributed to the breed's small founder population from which the breed evolved. Aside from a small initial population, "artificial genetic bottlenecks" have also occurred as breeders attempt to produce desirable traits in the canine. The team proved the point on genetic diversity when it studied a sample of 102 English bulldogs registered for breeding purposes. Against this sample, the researchers examined 37 additional English bulldogs that were brought to the University of California Davis Veterinary Clinical Services because of health problems. "We tried not to be judgemental in our paper," Niels Pedersen, a UC Davis professor who co-authored the study, tells the BBC News. "We just said there's a problem here, and if you are going to decide to do something about it, this is what you've got to work with." If inbreeding has placed the English bulldog's health in danger, how then can breeders save the canine? The short answer is to crossbreed with another canine that carries similar phenotypic traits but has a different genetic constitution. "Trying to manipulate diversity from within a breed if it doesn't have much anyway is really very difficult," Pedersen says. "If all your dogs are highly related to one another, which ones are you going to pick?" © 2016 Tech Times, All rights reserved. Do not reproduce without permission.