Archive for the ‘ecology’ Category

A Few Winners, But Many More Losers: Southwestern Bird and Reptile Distributions to Shift as Climate Changes

April 9, 2014 Comments off

A Few Winners, But Many More Losers: Southwestern Bird and Reptile Distributions to Shift as Climate Changes
Source: U.S. Geological Survey

Dramatic distribution losses and a few major distribution gains are forecasted for southwestern bird and reptile species as the climate changes, according to just-published research by scientists with the U.S. Geological Survey, the University of New Mexico, and Northern Arizona University.

Overall, the study forecasted species distribution losses – that is, where species are able to live – of nearly half for all but one of the 5 reptile species they examined, including for the iconic chuckwalla. The threatened Sonoran (Morafka’s) desert tortoise, however, is projected to experience little to no habitat losses from climate change.

Breeding bird ranges exhibited greater expansions and contractions than did reptile species. For example, black-throated sparrows and gray vireos are projected to experience major gains in breeding habitat, but pygmy nuthatches, sage thrashers and Williamson sapsuckers are forecasted to experience large losses in breeding habitat, in some cases by as much as 80 percent. Thus, these three species might be expected to experience large future population declines.

The iconic pinyon jay is expected to experience from one-fourth to one-third loss in breeding habitat in the future, as its welfare is tied to declining pinyon pine habitat.

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CRS — Changes in the Arctic: Background and Issues for Congress (updated)

April 8, 2014 Comments off

Changes in the Arctic: Background and Issues for Congress (PDF)
Source: Congressional Research Service (via University of North Texas Digital Library)

The diminishment of Arctic sea ice has led to increased human activities in the Arctic, and has heightened interest in, and concerns about, the region’s future. The United States, by virtue of Alaska, is an Arctic country and has substantial interests in the region. On May 10, 2013, the Obama Administration released a national strategy document for the Arctic region. On January 30, 2014, the Obama Administration released an implementation plan for this strategy.

Record low extents of Arctic sea ice over the past decade have focused scientific and policy attention on links to global climate change and projected ice-free seasons in the Arctic within decades. These changes have potential consequences for weather in the United States, access to mineral and biological resources in the Arctic, the economies and cultures of peoples in the region, and national security.

Homing of invasive Burmese pythons in South Florida: evidence for map and compass senses in snakes

April 1, 2014 Comments off

Homing of invasive Burmese pythons in South Florida: evidence for map and compass senses in snakes
Source: Biology Letters

Navigational ability is a critical component of an animal’s spatial ecology and may influence the invasive potential of species. Burmese pythons (Python molurus bivittatus) are apex predators invasive to South Florida. We tracked the movements of 12 adult Burmese pythons in Everglades National Park, six of which were translocated 21–36 km from their capture locations. Translocated snakes oriented movement homeward relative to the capture location, and five of six snakes returned to within 5 km of the original capture location. Translocated snakes moved straighter and faster than control snakes and displayed movement path structure indicative of oriented movement. This study provides evidence that Burmese pythons have navigational map and compass senses and has implications for predictions of spatial spread and impacts as well as our understanding of reptile cognitive abilities.

Oxygen requirements of the earliest animals

March 24, 2014 Comments off

Oxygen requirements of the earliest animals
Source: Proceedings of the National Academy of Sciences

A rise in the oxygen content of the atmosphere and oceans is one of the most popular explanations for the relatively late and abrupt appearance of animal life on Earth. In this scenario, Earth’s surface environment failed to meet the high oxygen requirements of animals up until the middle to late Neoproterozoic Era (850–542 million years ago), when oxygen concentrations sufficiently rose to permit the existence of animal life for the first time. Although multiple lines of geochemical evidence support an oxygenation of the Ediacaran oceans (635–542 million years ago), roughly corresponding with the first appearance of metazoans in the fossil record, the oxygen requirements of basal animals remain unclear. Here we show that modern demosponges, serving as analogs for early animals, can survive under low-oxygen conditions of 0.5–4.0% present atmospheric levels. Because the last common ancestor of metazoans likely exhibited a physiology and morphology similar to that of a modern sponge, its oxygen demands may have been met well before the enhanced oxygenation of the Ediacaran Period. Therefore, the origin of animals may not have been triggered by a contemporaneous rise in the oxygen content of the atmosphere and oceans. Instead, other ecological and developmental processes are needed to adequately explain the origin and earliest evolution of animal life on Earth.

Artificial light puts ecosystem services of frugivorous bats at risk

March 18, 2014 Comments off

Artificial light puts ecosystem services of frugivorous bats at risk
Source: Journal of Applied Ecology

1. Currently, tropical forests are transformed into pasture and agricultural areas at an unprecedented rate, yet converted areas are often abandoned by farmers because depleting soil fertility renders unprofitable any agricultural land use. Natural succession of abandoned land could counter the loss of biodiversity, but the rate of natural reforestation is slow.

2. Neotropical frugivorous bats facilitate natural succession because they seem to tolerate habitat disturbance when dispersing seeds of pioneer plants. Under naturally dark conditions, bats produce a copious seed rain even in deforested habitats and connect distant forest fragments. Yet, artificial light at night may compromise bat-mediated seed dispersal if bats avoid lit areas. This may delay or jeopardize natural forest succession in fragmented tropical landscapes.

3. We asked whether the foraging behaviour of Sowell’s short-tailed bats Carollia sowelli, a specialist on infructescences of pepper plants (Piperaceae), is negatively affected by artificial light at night.

4. First, in a dual choice experiment with captive bats, we demonstrate that food was less often explored and consumed in the dimly illuminated than in the dark compartment, indicating that artificial light alters the foraging behaviour of fruit-eating bats. Secondly, using observations in free-ranging bats, we found that infructescences were less likely to be harvested when plants were illuminated by a street lamp than under natural darkness.

5. Synthesis and applications. Natural succession of deforested areas and connectivity of remaining forest patches may suffer due to artificial light at night through a reduction in nocturnal seed disperser activity in lit areas. This could have negative impacts on biodiversity and consequent effects on land erosion, particularly in developing countries of the tropics where light pollution increases rapidly with growing economies and human populations. Mitigation requires that the use of artificial light should be limited in space, time and intensity to the minimum necessary. The effectiveness of ‘darkness corridors’ to enhance fragment connectivity and to reduce species loss should be evaluated. Policy-makers of tropical countries should become aware of the potential detrimental effects of artificial lighting on wildlife and ecosystem functioning.

See: How Urban Light Pollution Could Be Killing Rainforests (Atlantic Cities)

Deer Browsing Delays Succession by Altering Aboveground Vegetation and Belowground Seed Banks

March 17, 2014 Comments off

Deer Browsing Delays Succession by Altering Aboveground Vegetation and Belowground Seed Banks
Source: PLoS ONE

Soil seed bank composition is important to the recovery of natural and semi-natural areas from disturbance and serves as a safeguard against environmental catastrophe. White-tailed deer (Odocoileus virginianus) populations have increased dramatically in eastern North America over the past century and can have strong impacts on aboveground vegetation, but their impacts on seed bank dynamics are less known. To document the long-term effects of deer browsing on plant successional dynamics, we studied the impacts of deer on both aboveground vegetation and seed bank composition in plant communities following agricultural abandonment. In 2005, we established six 15×15 m fenced enclosures and paired open plots in recently fallowed agricultural fields near Ithaca, NY, USA. In late October of each of six years (2005–2010), we collected soil from each plot and conducted seed germination cycles in a greenhouse to document seed bank composition. These data were compared to measurements of aboveground plant cover (2005–2008) and tree density (2005–2012). The impacts of deer browsing on aboveground vegetation were severe and immediate, resulting in significantly more bare soil, reduced plant biomass, reduced recruitment of woody species, and relatively fewer native species. These impacts persisted throughout the experiment. The impacts of browsing were even stronger on seed bank dynamics. Browsing resulted in significantly decreased overall species richness (but higher diversity), reduced seed bank abundance, relatively more short-lived species (annuals and biennials), and fewer native species. Both seed bank richness and the relative abundance of annuals/biennials were mirrored in the aboveground vegetation. Thus, deer browsing has long-term and potentially reinforcing impacts on secondary succession, slowing succession by selectively consuming native perennials and woody species and favoring the persistence of short-lived, introduced species that continually recruit from an altered seed bank.

See: Deer proliferation disrupts a forest’s natural growth (Science Daily)

Categories: ecology, PLoS ONE

A Global Evaluation of Biodiversity Literacy in Zoo and Aquarium Visitors

March 7, 2014 Comments off

A Global Evaluation of Biodiversity Literacy in Zoo and Aquarium Visitors
Source: World Association of Zoos and Aquariums
From press release:

On the occasion of World Wildlife Day, the World Association of Zoos and Aquariums (WAZA), in association with Chester Zoo and a researcher at the University of Warwick, publishes a report of its global survey evaluating educational impacts on zoo and aquarium visitors (“A Global Evaluation of Biodiversity Literacy in Zoo and Aquarium Visitors”).

As a result, visits to zoos and aquariums clearly showed a positive impact. Dr Eric Jensen (Associate Professor, University of Warwick) said: “This study offers the first large-scale international evidence that zoos and aquariums can effectively engage their visitors with biodiversity. This question of educational impact has loomed over zoos and aquariums for decades. Our findings indicate that zoos and aquariums are right to tout their potential as sites for engagement with wildlife, although some of these attractions are clearly more effective than others.”

CRS — Asian Carp and the Great Lakes Region

March 5, 2014 Comments off

Asian Carp and the Great Lakes Region (PDF)
Source: Congressional Research Service (via Federation of American Scientists)

Four species of non-indigenous Asian carp are expanding their range in U.S. waterways, resulting in a variety of concerns and problems. Three species—bighead, silver, and black carp—are of particular note, based on the perceived degree of environmental concern. Current controversy relates to what measures might be necessary and sufficient to prevent movement of Asian carp from the Mississippi River drainage into the Great Lakes through the Chicago Area Waterway System. Several bills have been introduced in the 113th Congress to direct actions to avoid the possibility of carp becoming established in the Great Lakes.

According to the Great Lakes Fishery Commission, Asian carp pose a significant threat to commercial and recreational fisheries of the Great Lakes. Asian carp populations could expand rapidly and change the composition of Great Lakes ecosystems. Native species could be harmed because Asian carp are likely to compete with them for food and modify their habitat. It has been widely reported that Great Lakes fisheries generate economic activity of approximately $7 billion annually. Although Asian carp introduction is likely to modify Great Lakes ecosystems and cause harm to fisheries, studies forecasting the extent of potential harm are not available. Therefore, it is not possible to provide estimates of potential changes in the regional economy or economic value (social welfare) by lake, species, or fishery.

Understanding the Connections Between Coastal Waters and Ocean Ecosystem Services and Human Health: Workshop Summary (2014)

March 5, 2014 Comments off

Understanding the Connections Between Coastal Waters and Ocean Ecosystem Services and Human Health:
Workshop Summary (2014)

Source: Institute of Medicine

Understanding the Connections Between Coastal Waters and Ocean Ecosystem Services and Human Health discusses the connection of ecosystem services and human health. This report looks at the state of the science of the role of oceans in ensuring human health and identifies gaps and opportunities for future research. The report summarizes a workshop convened by the Institute of Medicine’s Roundtable on Environmental Health Sciences, Research, and Medicine. Participants discussed coastal waters and ocean ecosystem services in the United States in an effort to understand impacts on human health. Understanding the Connections Between Coastal Waters and Ocean Ecosystem Services and Human Health focuses on key linkages by discussing the ecosystem services provided by coastal waterways and oceans that are essential for human health and well-being; examining the major stressors that affect the ability of coastal waterways and ocean systems to provide essential services; and considering key factors that can enhance the resiliency of these systems.

CRS — The Lacey Act: Protecting the Environment by Restricting Trade

March 4, 2014 Comments off

The Lacey Act: Protecting the Environment by Restricting Trade (PDF)
Source: Congressional Research Service (via National Agricultural Law Center)

The Lacey Act was enacted in 1900 to prevent hunters from illegally killing game in one state and escaping prosecution by crossing state lines. It has evolved into a law that prohibits import, export, transport, purchase, or sale of species when that action would violate state, federal, tribal, or foreign law. Congress amended the Lacey Act most recently in 2008, expanding the reach of the act to include timber and timber products. Implementation of the 2008 Amendments has proved controversial, and the Department of Agriculture Animal and Plant Health Inspection Service (APHIS) initially delayed implementing the act’s new declaration requirements for importing wood products.

Some find the Lacey Act puzzling. While people charged with violating the act are charged with violating a U.S. law, that prosecution is premised on a violation of another law, sometimes the law of another country. That has led some to claim that the United States is enforcing the laws of another country. U.S. conservation laws (such as the Lacey Act), however, have long protected species and habitats even outside of the United States. Worldwide conservation was one reason for expanding Lacey Act coverage to more plants in 2008. Preserving U.S. timber jobs and prices was another reason.

UK — Wildlife Law: Control of Invasive Non-native Species

February 26, 2014 Comments off

Wildlife Law: Control of Invasive Non-native Species
Source: Law Commission of England

On 11 February 2014, we published our final report, Wildlife Law: Control of Invasive Non-native Species. This is the first item to be delivered from the full project. This element of the project was brought forward at the request of Defra and the Welsh Government to enable them to consider whether to introduce early legislation.

Invasive non-native species are ones that arrive as a result of human action and cause environmental and economic damage. They pose a significant threat to ecosystems as well as damaging property and infrastructure. Existing law does not contain sufficient powers to allow for their timely and effective control or eradication. Our recommendations in relation to species control orders will allow for a proportionate and necessary response to an increasing problem.

The Rise of Superweeds—and What to Do About It

February 23, 2014 Comments off

The Rise of Superweeds—and What to Do About It
Source: Union of Concerned Scientists

It sounds like a sci-fi movie: American farmers fighting desperately to hold back an onslaught of herbicide-defying “superweeds.”

But there’s nothing imaginary—or entertaining—about this scenario. Superweeds are all too real, and they have now spread to over 60 million acres of our farmland, wreaking environmental and economic havoc wherever they go.

How did we get into this mess, and how do we fix it? A 2013 UCS briefing paper, The Rise of Superweeds—and What to Do About It, answers these questions.

Gathering “wild” food in the city: rethinking the role of foraging in urban ecosystem planning and management

February 12, 2014 Comments off

Gathering “wild” food in the city: rethinking the role of foraging in urban ecosystem planning and management
Source: U.S. Forest Service

Recent “green” planning initiatives envision food production, including urban agriculture and livestock production, as desirable elements of sustainable cities. We use an integrated urban political ecology and human-plant geographies framework to explore how foraging for “wild” foods in cities, a subversive practice that challenges prevailing views about the roles of humans in urban green spaces, has potential to also support sustainability goals. Drawing on research from Baltimore, New York City, Philadelphia, and Seattle, we show that foraging is a vibrant and ongoing practice among diverse urban residents in the USA. At the same time, as reflected in regulations, planning practices, and attitudes of conservation practitioners, it is conceptualised as out of place in urban landscapes and an activity to be discouraged. We discuss how paying attention to urban foraging spaces and practices can strengthen green space planning and summarise opportunities for and challenges associated with including foragers and their concerns.

CRS — Wildfire Fuels and Fuel Reduction

February 11, 2014 Comments off

Wildfire Fuels and Fuel Reduction (PDF)
Source: Congressional Research Service (via Federation of American Scientists)

Severe wildfires have been burning more acres and more structures in recent years. Some assert that climate change is at least partly to blame; others claim that the increasing number of homes in and near the forest (the wildland-urban interface) is a major cause. However, most observers agree that wildfire suppression and historic land management practices have led to unnaturally high accumulations of biomass in many forests, particularly in the intermountain West. While high-intensity conflagrations (wildfires that burn the forest canopy) occur naturally in some ecosystems (called crown-fire or stand-replacement fire ecosystems), abnormally high biomass levels can lead to conflagrations in ecosystems when such crown fires were rare (called frequentsurface- fire ecosystems). Thus, many propose activities to reduce forest biomass fuels.

The characteristics of forest biomass fuels affect the nature, spread, and intensity of the fire. Fuel moisture content is critical, but is generally a function of weather patterns over hours, days, and weeks. Fuel size is also important—fine and small fuels (e.g., needles, grasses, leaves, small twigs) are key to fire spread, while larger fuels (e.g., twigs larger than pencil-diameter, branches, and logs) contribute primarily to fire intensity; both are important to minimizing fire damages. Fuel distribution can also affect damages. Relatively continuous fuels improve burning, and vertically continuous fuels—fuel ladders—can lead a surface fire into the canopy, causing a conflagration. Total fuel accumulations (fuel loads) also contribute to fire intensity and damage. Thus, activities that alter biomass fuels—reducing total loads, reducing small fuels, reducing large fuels, and eliminating fuel ladders—can help reduce wildfire severity and damages.

Climate Change Increases Reproductive Failure in Magellanic Penguins

February 5, 2014 Comments off

Climate Change Increases Reproductive Failure in Magellanic Penguins
Source: PLoS ONE

Climate change is causing more frequent and intense storms, and climate models predict this trend will continue, potentially affecting wildlife populations. Since 1960 the number of days with >20 mm of rain increased near Punta Tombo, Argentina. Between 1983 and 2010 we followed 3496 known-age Magellanic penguin (Spheniscus magellanicus) chicks at Punta Tombo to determine how weather impacted their survival. In two years, rain was the most common cause of death killing 50% and 43% of chicks. In 26 years starvation killed the most chicks. Starvation and predation were present in all years. Chicks died in storms in 13 of 28 years and in 16 of 233 storms. Storm mortality was additive; there was no relationship between the number of chicks killed in storms and the numbers that starved (P = 0.75) or that were eaten (P = 0.39). However, when more chicks died in storms, fewer chicks fledged (P = 0.05, R2 = 0.14). More chicks died when rainfall was higher and air temperature lower. Most chicks died from storms when they were 9–23 days old; the oldest chick killed in a storm was 41 days old. Storms with heavier rainfall killed older chicks as well as more chicks. Chicks up to 70 days old were killed by heat. Burrow nests mitigated storm mortality (N = 1063). The age span of chicks in the colony at any given time increased because the synchrony of egg laying decreased since 1983, lengthening the time when chicks are vulnerable to storms. Climate change that increases the frequency and intensity of storms results in more reproductive failure of Magellanic penguins, a pattern likely to apply to many species breeding in the region. Climate variability has already lowered reproductive success of Magellanic penguins and is likely undermining the resilience of many other species.

See also: Antarctic Climate Change: Extreme Events Disrupt Plastic Phenotypic Response in Adélie Penguins

Extinction risk and conservation of the world’s sharks and rays

February 4, 2014 Comments off

Extinction risk and conservation of the world’s sharks and rays
Source: eLife

The rapid expansion of human activities threatens ocean-wide biodiversity. Numerous marine animal populations have declined, yet it remains unclear whether these trends are symptomatic of a chronic accumulation of global marine extinction risk. We present the first systematic analysis of threat for a globally distributed lineage of 1,041 chondrichthyan fishes—sharks, rays, and chimaeras. We estimate that one-quarter are threatened according to IUCN Red List criteria due to overfishing (targeted and incidental). Large-bodied, shallow-water species are at greatest risk and five out of the seven most threatened families are rays. Overall chondrichthyan extinction risk is substantially higher than for most other vertebrates, and only one-third of species are considered safe. Population depletion has occurred throughout the world’s ice-free waters, but is particularly prevalent in the Indo-Pacific Biodiversity Triangle and Mediterranean Sea. Improved management of fisheries and trade is urgently needed to avoid extinctions and promote population recovery.

Categories: ecology, eLife

CRS — Wetlands: An Overview of Issues

January 28, 2014 Comments off

Wetlands: An Overview of Issues (PDF)
Source: Congressional Research Service (via National Agricultural Law Librar)

Recent Congresses have considered numerous policy topics that involve wetlands. Many reflect issues of long-standing interest, such as applying federal regulations on private lands, wetland loss rates, and restoration and creation accomplishments.

The issue receiving the greatest attention recently has been determining which wetlands should be included and excluded from permit requirements under the Clean Water Act’s (CWA) program that regulates waste discharges affecting wetlands, which is administered by the Army Corps of Engineers and the Environmental Protection Agency (EPA). As a result of Supreme Court rulings in 2001 (in the SWANCC case) that narrowed federal regulatory jurisdiction over certain isolated wetlands, and in 2006 (in the Rapanos-Carabell decision), the jurisdictional reach of the permit program has been narrowed. In response, legislation intended to reverse the Court’s rulings in these cases has been introduced regularly since the 107th Congress. In the 111th Congress, for the first time, one such bill was approved by a congressional committee (S. 787, the Clean Water Restoration Act); no further legislative action occurred. The Obama Administration did not endorse any specific legislation, but identified general principles for legislation that would clarify waters protected by the CWA. In 2011 the Administration proposed new interpretive guidance intended to clarify jurisdictional uncertainties resulting from the Court’s rulings and to apply protection to additional waters and wetlands, a conclusion that pleased some observers and alarmed others. In September 2013, EPA and the Corps withdrew the 2011 proposed guidance, which had not been finalized, in favor of draft revised regulations, which are being reviewed by the Office of Management and Budget.

Wetland protection efforts continue to engender controversy over issues of science and policy. Controversial topics include the rate and pattern of loss, whether all wetlands should be protected in a single fashion, the effectiveness of the current suite of laws in protecting them, and the fact that 75% of remaining U.S. wetlands are located on private lands.

Agricultural Policies Exacerbate Honeybee Pollination Service Supply-Demand Mismatches Across Europe

January 13, 2014 Comments off

Agricultural Policies Exacerbate Honeybee Pollination Service Supply-Demand Mismatches Across Europe
Source: PLoS ONE

Declines in insect pollinators across Europe have raised concerns about the supply of pollination services to agriculture. Simultaneously, EU agricultural and biofuel policies have encouraged substantial growth in the cultivated area of insect pollinated crops across the continent. Using data from 41 European countries, this study demonstrates that the recommended number of honeybees required to provide crop pollination across Europe has risen 4.9 times as fast as honeybee stocks between 2005 and 2010. Consequently, honeybee stocks were insufficient to supply >90% of demands in 22 countries studied. These findings raise concerns about the capacity of many countries to cope with major losses of wild pollinators and highlight numerous critical gaps in current understanding of pollination service supplies and demands, pointing to a pressing need for further research into this issue.

Fire Management and Invasive Plants: A Handbook

December 26, 2013 Comments off

Fire Management and Invasive Plants: A Handbook (PDF)
Source: U.S. Fish and Wildlife Service

Fire management can help maintain natural habitats, increase forage for wildlife, reduce fuel loads that might otherwise lead to catastrophic wildfire, and maintain natural succession. Today, there is an emerging challenge that fire managers need to be aware of: invasive plants. Fire management activities can create ideal opportunities for invasions by nonnative plants, potentially undermining the benefits of fire management actions.

This manual provides practical guidelines that fire managers should consider with respect to invasive plants.

The Urbanization of the Eastern Gray Squirrel in the United States

December 9, 2013 Comments off

The Urbanization of the Eastern Gray Squirrel in the United States
Source: Journal of American History

The urbanization of the gray squirrel in the United States between the mid-nineteenth century and the early twentieth century was an ecological and cultural process that changed the squirrels’ ways of life, altered the urban landscape, and adjusted human understandings of nature, the city, and the boundaries of community. Squirrels were part of the new complex of human-animal relationships that emerged in the American city at the turn of the twentieth century as laboring animals were replaced by machines, and as dairy, meat, and egg production and processing were shifted to the urban margins. Accounts of urban squirrels in newspapers, magazines, scientific journals, diaries, and other sources provide evidence of these changes and of the development of a new understanding of community that crossed species borders to include some types of animals and exclude some types of humans. These sources help explain why Bailey and many others saw the eastern gray squirrel not merely as an interesting object of nature study but also as a morally significant member of the urban community


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