نتایج جستجو برای: small island
تعداد نتایج: 838036 فیلتر نتایج به سال:
The island rule is a hypothesis whereby small mammals evolve larger size on islands while large insular mammals dwarf. The rule is believed to emanate from small mammals growing larger to control more resources and enhance metabolic efficiency, while large mammals evolve smaller size to reduce resource requirements and increase reproductive output. We show that there is no evidence for the exis...
Island endemics are expected to have low effective population sizes (Ne), first because some may experience population bottlenecks when they are founded, and second because they have restricted ranges. Therefore, we expect island species to have reduced genetic diversity, inefficient selection, and reduced adaptive potential compared with their mainland counterparts. We used both polymorphism a...
Tristan da Cunha is the world’s remotest inhabited island, with a population of around 270 people. Ship rats (Rattus rattus) and house mice (Mus musculus) are present on the main island of Tristan and house mice are present on Gough Island, also part of the UK Overseas Territory of Tristan da Cunha. The impacts of invasive rodents on both islands have been well documented and detailed plans to ...
The evolutionary mechanisms generating the tremendous biodiversity of islands have long fascinated evolutionary biologists. Genetic drift and divergent selection are predicted to be strong on islands and both could drive population divergence and speciation. Alternatively, strong genetic drift may preclude adaptation. We conducted a genomic analysis to test the roles of genetic drift and diverg...
Migration remains one of the great mysteries of animal life. Small migratory birds rely on refuelling stopovers after crossing ecological barriers such as deserts or seas. Previous studies have suggested that fuel reserves may determine stopover duration but this hypothesis could not be tested because of methodological limitations. Here, we provide evidence that subcutaneous fat stores determin...
We present a rate equation model for submonolayer island growth under conditions where hyperthermal deposition techniques such as low-energy ion deposition are employed to achieve smooth layer-by-layer growth. By asymptotic analysis, we demonstrate that the model exhibits stationary behavior with well-defined dynamic and growth exponents beta and chi, respectively, in the limit of small and hig...
“The Lost Princess (putri duyung)” of the Small Islands: Dugongs around Sulawesi in the Anthropocene
In the Spermonde as in the other main island groups around Sulawesi, seagrass and coral ecosystems are intimately linked ecologically and overlap extensively on the shallow water shelves surrounding most islands. One keystone species living in these shallow waters is the dugong (Dugong dugon). Officially fully protected under Indonesian Law (PP7/1999), published data on dugongs in the islands a...
A problem confronting Snowy Owls (Nyctea scandiaca) in their southern incursions is the shortage of food. This difficulty is raised by the presence of other raptors that feed on small mammals. This note shows how little food is found by migrant Snowy Owls and indicates a complex temporary ecological solution. At Tatoosh Island, Washington (48”24’ N, 124” 44’ W) on 25 November 1973, we observed ...
The influence of the ion polarization current on the stability of a constantmagnetic island in a tokamak plasma is investigated numerically using a reduced two-fluid model in two-dimensional slab geometry. The polarization current is found to be negligibly small when the island is either too narrow or too wide. However, under certain circumstances, there exists an intermediate regime in which t...
Kilauea Volcano on the Big Island of Hawaii may be an important source of bioavailable phosphorus to the Hawaiian Island Chain. Because it has been hypothesized that these volcanic islands undergo a shift from nitrogen to phosphorus limitation over geologic time, atmospheric phosphorus deposition could play a considerable role in ecosystem processes, especially on the older, more highly weather...
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