The Valdivian temperate rainforest of southern Chile and adjacent Argentina
supports a diverse and unique biota, with a high percentage of endemic spe
cies. Progressive exploitation of these forests, especially in the Central
Depression of southern Chile, has resulted in a complex and increasingly fr
agmented environment composed of isolated forest remnants in a landscape do
minated by grazing and crop cultivation. To assess the consequences of this
fragmentation, fourteen remnants were surveyed for small mammals during th
e winters of 1985 and 1986, and four of these were sampled in both years. N
either numbers of species (S), relative population sizes (n(R)), or species
diversity (H') were significantly related either to trapping effort or rem
nant area or perimeter, and only n(R) was significantly predicted by the ar
ea/perimeter ratio. Three native rodent species were found on all remnants
in both years, and three additional native and one introduced rodent, and t
wo marsupials, were found in lesser numbers and in Fewer remnants. (C) 2000
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