نتایج جستجو برای: forest fragmentation
تعداد نتایج: 139402 فیلتر نتایج به سال:
I report on a documented dieback in spicebush, Lindera benzoin, after the winter of 1993-1994 in two mature deciduous forest stands in southwestern Ohio. The study compares differences between 67 ha Hueston Woods and 5.2 ha Kramer Woods and examines spatial patterns of decline in Kramer Woods. Local daily minimum temperatures in January 1994 were among the coldest on record since 1889The shrub ...
Volcanic activity on the island of Hawaii results in a cyclical pattern of habitat destruction and fragmentation by lava, followed by habitat regeneration on newly formed substrates. While this pattern has been hypothesized to promote the diversification of Hawaiian lineages, there have been few attempts to link geological processes to measurable changes in population structure. We investigated...
Forest fragmentation is considered a greater threat to vertebrates than to tree communities because individual trees are typically long-lived and require only small areas for survival. Here we show that forest fragmentation provokes surprisingly rapid and profound alterations in Amazonian tree-community composition. Results were derived from a 22-year study of exceptionally diverse tree communi...
A new deforestation and land-use change scenario generator model (FOREST-SAGE) is presented that is designed to interface directly with dynamic vegetation models used in latest generation earth system models. The model requires a regional-scale scenario for aggregate land-use change that may be time-dependent, provided by observational studies or by regional land-use change/economic models for ...
0006-3207/$ see front matter 2008 Elsevier Ltd. A doi:10.1016/j.biocon.2008.11.016 * Corresponding author. Tel.: +55 11 30917603; fax E-mail addresses: [email protected] ( Metzger), [email protected] (J.S. Morgante), kell Zamudio). Tropical rainforests are becoming increasingly fragmented and understanding the genetic consequences of fragmentation is crucial for conservation of their f...
Field studies in eastern North America indicate that local densities of most forest-dwelling bird species are directly or indirectly influenced by forest insularization. Relevant site variables among those measured include patch area and isolation, tree stature and density, and development of herbaceous and shrub understorey. In general, highly migratory species that specialize on forest-interi...
Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million fores...
The Atlantic Forest has a high destruction rate and there is little information available on some aspects of the neotropical bird biology. Changes in environment are important factors that affect the resources available to birds. We compared the species sensitivity level of understorey birds in two areas in distinct successional stages (primary and secondary sections). Two 100 ha plots of lowla...
Huge areas of diverse tropical forest are lost or degraded every year with dramatic consequences for biodiversity. Deforestation and fragmentation, over-exploitation, invasive species and climate change are the main drivers of tropical forest biodiversity loss. Most studies investigating these threats have focused on changes in species richness or species diversity. However, if we are to unders...
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