نتایج جستجو برای: family change

تعداد نتایج: 993986  

2013
Linda J Gormezano Robert F Rockwell

Under current climate trends, spring ice breakup in Hudson Bay is advancing rapidly, leaving polar bears (Ursus maritimus) less time to hunt seals during the spring when they accumulate the majority of their annual fat reserves. For this reason, foods that polar bears consume during the ice-free season may become increasingly important in alleviating nutritional stress from lost seal hunting op...

Journal: :Proceedings. Biological sciences 2004
Conrad A Matthee Colin R Tilbury Ted Townsend

The phylogenetic associations among 13 currently recognized African leaf chameleon species were investigated by making use of mitochondrial and nuclear DNA sequence data (44 taxa and 4145 characters). The gene tree indicates two divergent clades within Rhampholeon; this finding is congruent with previous morphological suggestions. The first clade (I) comprises three taxa (R. kerstenii, R. brevi...

2015
S. Sinha C. Jeganathan L. K. Sharma M. S. Nathawat

Forest plays a vital role in regulating climate through carbon sequestration in its biomass. Biomass reflects the health and environmental conditions of a forest ecosystem. In context to the climate change mitigation mechanisms like REDD (reducing emissions from deforestation and forest degradation), an extensive forest monitoring campaign is especially important. Remote sensing of forest struc...

2017
Eric V Regehr Ryan R Wilson Karyn D Rode Michael C Runge Harry L Stern

The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to envi...

Journal: :Bulletin of the World Health Organization 2009
Leo Bryant Louise Carver Colin D Butler Ababu Anage

The links between rapid population growth and concerns regarding climate change have received little attention. Some commentators have argued that slowing population growth is necessary to reduce further rises in carbon emissions. Others have objected that this would give rise to dehumanizing 'population control' programmes in developing countries. Yet the perspective of the developing countrie...

Journal: :Current Biology 2014
Terry P. Hughes David R. Bellwood Sean R. Connolly Howard V. Cornell Ronald H. Karlson

Coral reefs are critically important ecosystems that support the food security and livelihoods of hundreds of millions of people in maritime tropical countries, yet they are increasingly threatened by overfishing, coastal pollution, climate change, and other anthropogenic impacts, leading to concerns that some species may be threatened with local or even global extinction. The concept of double...

2014
Seth Stapleton Michelle LaRue Nicolas Lecomte Stephen Atkinson David Garshelis Claire Porter Todd Atwood

Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high den...

2016
Linda J. Gormezano Scott R. McWilliams David T. Iles Robert F. Rockwell

Trade-offs between locomotory costs and foraging gains are key elements in determining constraints on predator-prey interactions. One intriguing example involves polar bears pursuing snow geese on land. As climate change forces polar bears to spend more time ashore, they may need to expend more energy to obtain land-based food. Given that polar bears are inefficient at terrestrial locomotion, a...

2016
Jordan York Martha Dowsley Adam Cornwell Miroslaw Kuc Mitchell Taylor

Subpopulation growth rates and the probability of decline at current harvest levels were determined for 13 subpopulations of polar bears (Ursus maritimus) that are within or shared with Canada based on mark-recapture estimates of population numbers and vital rates, and harvest statistics using population viability analyses (PVA). Aboriginal traditional ecological knowledge (TEK) on subpopulatio...

2016
Dennis R. Ruez

At least 17 carnivoran taxa occur in the Pliocene Glenns Ferry Formation at Hagerman Fossil Beds National Monument (HAFO), Idaho. This assemblage was examined for stratigraphic changes in species distribution, specimen abundance, and species diversity. Three relatively common mustelids, Trigonictis cookii, Trigonictis macrodon, and Mustela rexroadensis, occur at most stratigraphic levels, but a...

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