Browsing by Author "Cornelius, C"

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    Conservation of temperate forest birds in Chile
    (2002) Reid, S; Cornelius, C; Barbosa, O; Meynard, C; Silva-García, C; Marquet, PA
    We characterize the bird assemblage of an isolated relict temperate rainforest (Santa Ines) in terms of its structure, composition and dynamics. The relict character and long-term isolation of this forest remnant, immersed in a matrix of semiarid scrub, provide a natural experiment to assess the consequences of long-term isolation and forest area reduction for temperate bird species. Bird surveys were conducted in a forest fragment and the surrounding scrub matrix between April 1999 (austral autumn) and October 2000 (austral spring) on a seasonal basis. Within the forest fragment we distinguished two microhabitat types: creeks and areas far from creeks (i.e. slopes). A total of 36 species were recorded in the study site, of which 21 were inside the relict forest. Highest bird abundance and richness were recorded during winter and spring, and these were always higher in creek plots rather than slope plots. Comparisons between this assemblage and those distributed in the continuous temperate forest (located more than 900 km southwards) indicate that this bird assemblage shares more similarities, with regard to bird species composition, to southern temperate forest localities and to other relict forests, than to nearer scrub habitats. However, there are eight species, endemic to temperate forests in southern South America, missing from our system. In this regard, our analyses indicate that these eight endemic species should be of great conservation concern and will likely be the ones that will go extinct first if the fragmentation of the temperate forest continues.
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    Effects of habitat fragmentation on bird species in a relict temperate forest in semiarid Chile
    (2000) Cornelius, C; Cofré, H; Marquet, PA
    We analyzed the structure and composition of a bird assemblage in a fragmented relict temperate forest located in northcentral Chile (Fray Jorge National Park). In terms of species composition, the bird assemblage we found in Fray Jorge was more similar to southern temperate forest sites, located more than 1200 km south of Fray Jorge, than to localities found in nearby scrub habitats. The relict character and long-term isolation of the Fray Jorge forest provides a natural experiment with which to establish the potential long-term effects of fragmentation and isolation on southern Chilean temperate forests. Between May 1996 and March 1997, we conducted seasonal surveys of birds in six forest fragments, ranging in size from 0.5 to 22.5 ha, at Fray Jorge. The number of bird species at each forest fragment was positively correlated with fragment area during all seasons. The relict forest system had a steeper species-area slope than that reported for similar temperate-forest bird assemblages in forest fragments within Chiloe Island and for islands across the Chiloe Archipelago in southern Chile. In this regard, this bird fauna resembled a depauperate oceanic archipelago. This difference in area effects is likely a consequence of the minimization of rescue effects because of the absence of large source forest areas nearby and the long-term isolation of the system. In addition, the distribution of species among forest fragments in Fray Jorge was not random, showing a nested subset pattern. Thus, some species occur across all fragments, regardless of their area, and therefore are less affected by habitat fragmentation and less prone to local extinction. These results suggest that, for south-temperate forest birds, large fragments (or reserves) should afford better protection against extinction than small forest patches.