Patch-matrix interactions and bird species conservation in a plantation-dominated landscape in Australia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Conservation of wildlife and key ecological processes in production landscapes are essential for the achievement of ecologically sustainable natural resource use. Thus, investigations of wildlife response to landscape change have become critical. This thesis aims to obtain information useful for the better integration of wildlife conservation and wood production in plantation-dominated landscapes. This thesis examined the use of native eucalypt forests and exotic pine forests (the matrix) by bird species in a Radiata pine (Pinus radiata) plantation in the Tumut region, southern New South Wales, southeastern Australia. The main objectives were to: 1) examine the influence of attributes of patches of native forest and of exotic forest on bird occurrence in stands of pine forest; 2) verify the role of the matrix and of adjacent areas of eucalypt forest on bird occurrence in remnants of native forest located within the plantation; 3) review investigations conducted worldwide that examined variation in bird occurrence across habitat boundaries; 4) provide recommendations for bird conservation in wood production landscapes. To obtain data to address some of the key questions in this thesis, bird surveys were conducted by the area search method within quadrats located in native and exotic forests. Generalised Linear models (GLMs) were used for most analyses. Bird species richness found within stands of pine forest declined with increasing distance from adjacent patches of eucalypt forest (Chapters 4 and 6). This was due, in part, to the fact that several species found in native patches also use pine forests as additional foraging areas. Attributes of the matrix (age of pine forest) and the remnants of native forest (patch width and size) influenced bird occurrence in pine forests (Chapters 4 and 5). The term "Halo Effect" was introduced for the influence of patch attributes on the differential use of matrix. These results suggest that conservation efforts in patchy environments should protect not only native patches but also adjacent areas of matrix into which animals extend their home ranges/territories. The decline in species richness within pine forests with increasing distances from eucalypt forests also suggests that detections of bird species can vary substantially with the position of survey stations in relation to surrounding native vegetation (Chapter 6). Recent assessments of the conservation value of managed vegetation for birds have often failed to consider the potential importance of such influences. Bird species richness and the occurrence of several species in patches of eucalypt forest were influenced by patch width and the age of surrounding pine matrix (Chapter 7). Species occurrence in wide and narrow patches of native forest was related to their use of the matrix. This was true for native forests surrounded by old but not by young pine forests. Species richness in native forest remnants within the plantation also was influenced by distance from extensive conservation areas of similar native forest (Chapter 8). This result is in agreement with the peninsula effect - a decrease in species richness from the base to the top of peninsulas - but usually tested in a biogeographic scale. Finally, a review of investigations of bird occurrence across habitat boundaries revealed numerous factors and mechanisms influencing cross-boundaries movements and their response to adjacent habitat (Chapter 9). This chapter also compiled the conservation recommendations proposed in the studies. The findings of all chapters are discussed in a short synthesis (Chapter 10) the end of this thesis.

ASSUNTO(S)

conservação de biodiversidade matriz de paisagem planejamento de paisagem aves wildlife conservation wood production forest biodiversity birds occurrence production landscapes ecologia aplicada manejo florestal ecological processes

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