Tag Archives: ecosystem

Airborne Technology Helps Manage Elephants

By Guest PostAugust 26, 2012Environment, Nature3 d mapping, africa, airborne technology, atmosphere, cao, carbon, carnegie, climate, danie pienaar, ecology letters, ecosystem, elephant, elephant conservation, elephant trap, Environment, greg asner, habitat, herbivore, kruger national park, lidar, management practice, savanna, sequester, shaun levick, South Africa, terrain condition, toppling tree, treefall, vegetation

Washington, D.C. – For years, scientists have debated how big a role elephants play in toppling trees in South African savannas. Tree loss is a natural process, but it is increasing in some regions, with cascading effects on the habitat for many other species. Using high resolution 3-D mapping, Carnegie scientists have for the first time quantitatively determined tree losses across savannas of Kruger National Park. They found that elephants are the primary agents—their browsing habits knock trees over at a rate averaging 6 times higher than in areas inaccessible to them. The research also found that elephants prefer toppling trees in the 16-to-30 foot (5-8 m) range, with annual losses of up to 20% in these height classes. The findings, published in Ecology Letters, bolster our understanding of elephant conservation needs and their impacts, and the results could help to improve savanna management practices.

“Previous field studies gave us important clues that elephants are a key driver of tree losses, but our airborne 3-D mapping approach was the only way to fully understand the impacts of elephants across a wide range of environmental conditions found in savannas,” commented lead author Greg Asner of Carnegie’s Department of Global Ecology. “Our maps show that elephants clearly toppled medium-sized trees, creating an “elephant trap” for the vegetation. These elephant-driven tree losses have a ripple effect across the ecosystem, including how much carbon is sequestered from the atmosphere.” (more…)

Native Plants in Urban Yards Offer Birds “Mini-Refuges”

By Guest PostAugust 24, 2012Environment, Natureaberts towhee, arizona birds, behavior, biodiversity, bird, coral reef, curve billed thrasher, desert, doug levey, ecosystem, eyal shochat, forest, grassland, gud, hilary gan, house sparrow, lter, mini refuges, native plant, paige warren, residential landscape, sonoran desert, susannah lerman, urban yard, xeric

Landscaping with native vegetation helps local bird species

Yards with plants that mimic native vegetation offer birds “mini-refuges” and help to offset losses of biodiversity in cities, according to results of a study published on August 22, 2012 in the journal PLOS ONE.

“Native” yards support birds better than those with traditional grass lawns and non-native plantings.

Researchers conducted the study through the National Science Foundation’s (NSF) Central Arizona-Phoenix Long-Term Ecological Research (LTER) site, one of 26 such sites around the globe in ecosystems from coral reefs to deserts, from forests to grasslands. (more…)

Heather Leslie: Measuring ocean health

By Guest PostAugust 16, 2012Environmentaaas, artisanal fishing, biodiversity, carbon storage, clean waters, coastal livelihoods, coastal place, coastal protection, coral reefs, david orenstein, ecosystem, gulf of california, gulf region, habitat, heather leslie, index rate, mangroves, Mexico, ocean, ocean condition, ocean health index, ocean species, salt marshes, sea ice, seagrasses, sustainable management

Sustainable management of a huge, complex and valuable resource such as the ocean requires a comprehensive metric that did not exist until now. In the Aug. 16 edition of Nature a broad group of scientists including Heather Leslie, the Sharpe Assistant Professor of Environmental Studies, describes the Ocean Health Index. The index rates coastal places, from regions to nations, on 10 goals: artisanal fishing opportunity, biodiversity, carbon storage, clean waters, coastal livelihoods and economies, coastal protection, food provision, natural products, sense of place, and tourism and recreation. Leslie recently answered questions posed by David Orenstein.

How does the Ocean Health Index’s focus on integrating human factors make it different and valuable?

Recognizing people’s integral roles in ocean ecosystems, this index evaluates how well the ocean provides 10 key benefits to people and how well we are protecting its ability to do so in the future. (more…)

Study Proves that One Extinction Leads to Another

By Guest PostAugust 15, 2012Natureafrican plains, aphids, carnivore, ecosystem, extinction, food web, frank van veen, insects, parasitic wasps, predatory fish, predatory species, ripple effect, university of exeter

When a carnivore becomes extinct, other predatory species could soon follow, according to new research.

Scientists have previously put forward this theory, but a University of Exeter team has now carried out the first experiment to prove it.

Published today (15 August 2012) in the Royal Society journal Biology Letters, the study shows how the demise of one carnivore species can indirectly cause another to become extinct. The University of Exeter team believes any extinction can create a ripple effect across a food web, with far-reaching consequences for many other animals. (more…)

Recreational Fishing Brings Salt Marsh Die-Off

By Guest PostJune 18, 2012Environmentaerial photographs, alternative hypotheses, andrew altieri, blue crabs, brown university, cape cod, christine angelini, coastline, ecologists, ecosystem, erosion, factor, filter pollutants, fishermen, grasses, mark bertness, nicholas hermann, predator, protect, recreational fishing, salt marsh, sesarma crabs, sesarma populations, smooth dogfish, trophic cascade, tyler coverdale

As recreational fishing activity has reduced predators in many of Cape Cod’s salt marsh ecosystems, Sesarma crabs have feasted on grasses, causing dramatic die-offs of the marshes, according to a new study. The researchers assessed the “trophic cascade” in several experiments that also ruled out alternative explanations for the problem.

PROVIDENCE, R.I. [Brown University] — Recreational fishing is a major contributor to the rapid decline of important salt marshes along Cape Cod because it strips top predators such as striped bass, blue crabs, and smooth dogfish out of the ecosystem, according to new research by Brown University ecologists.

With far fewer predators in areas where recreational fishing is prevalent, native Sesarma crabs have had relatively free rein to eat salt marsh grasses, causing the ecosystem to collapse, said Mark Bertness, chair of Brown’s Department of Ecology and Evolutionary Biology and the paper’s senior author. He led a series of experiments and measurements published online in the journal Ecology that he said unavoidably implicate recreational fishing in marsh die-off. (more…)

Scientists Discover Huge Phytoplankton Bloom in Ice Covered Waters

By Guest PostJune 13, 2012Environmentalaska, aleutian islands, alga phaeocystis, arctic algal boom, arctic circle, arctic summer, arctic waters, beaufort seas, bob pickart, chlorophyll, climate change, continental shelf, ecosystem, emily peacock, healy, heidi sosik, ice free waters, icebreaker, icescape program, imaging flowcytobot, kevin arrigo, magnifying lenses, melt water, microscopic marine plants, NASA, optical measurements, phenomenon, photosynthetic, phytoplankton, polar chukchi, pools of water, rob olson, sam laney, sea ice, skylights, stanford university, thalassiosira, us coast guard, whoi

A team of researchers, including scientists from Woods Hole Oceanographic Institution (WHOI), discovered a massive bloom of phytoplankton beneath ice-covered Arctic waters. Until now, sea ice was thought to block sunlight and limit the growth of microscopic marine plants living under the ice.

The amount of phytoplankton growing in this under-ice bloom was four times greater than the amount found in neighboring ice-free waters. The bloom extended laterally more than 100 kilometers (62 miles) underneath the ice pack, where ocean and ice physics combined to create a phenomenon that scientists had never seen before. (more…)

Light Pollution Transforming Insect Communities

By Guest PostJune 1, 2012Environmentartificial lighting, balance, ecosystem, ecosystem services, falmouth, ground beetles, harvestmen, helston, insect communities, invertebrates, kevin murphy, light pollution, market town, scavenging species, species, street lighting, tom davies, university of exeter, urban spaces, west cornwall

Street lighting is transforming communities of insects and other invertebrates, according to research by the University of Exeter.

Published in the journal Biology Letters, the study shows for the first time that the balance of different species living together is being radically altered as a result of light pollution in our towns and cities.

Believed to be increasing by six per cent a year globally, artificial lighting is already known to affect individual organisms, but this is the first time that its impact on whole communities has been investigated.

This study shows that groups of invertebrates living near to artificial lights include more predators and scavengers. This could be impacting on the survival rates of different species, having a knock-on effect on birds and mammals that rely on these species for food. The effects could be affecting entire ecosystems and even humans. (more…)

Ecosystem Effects of Biodiversity Loss Could Rival Impacts of Climate Change, Pollution

By Guest PostMay 10, 2012Environment, Natureacid deposition, air pollution, algae, bacteria, biodiversity loss, biological diversity, bradley cardinale, california, canada, climate change, david hooper, ecosystem, environmental change, environmental stress, environmental stressors, extinction, forests, fungi, global warming, henry gholz, impact, leslie gonzalez, nutrient pollution, oxygen, ozone pollution, pollution, san josé, serpentine grasslands, Sweden, united states, university of michigan

ANN ARBOR, Mich.— Loss of biodiversity appears to impact ecosystems as much as climate change, pollution and other major forms of environmental stress, according to a new study from an international research team.

The study is the first comprehensive effort to directly compare the impacts of biological diversity loss to the anticipated effects of a host of other human-caused environmental changes.

The results highlight the need for stronger local, national and international efforts to protect biodiversity and the benefits it provides, according to the researchers, who are based at nine institutions in the United States, Canada and Sweden. (more…)