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Luis Miguel Renjifo - One of the best experts on this subject based on the ideXlab platform.
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Composition Changes in a Subandean Avifauna after Long‐Term Forest Fragmentation
Conservation Biology, 1999Co-Authors: Luis Miguel RenjifoAbstract:: Current understanding of the effects of forest fragmentation is based largely on studies in temperate regions, Australia, and Neotropical lowlands. In contrast, the consequences of anthropogenic forest fragmentation for Andean Avifaunas are poorly understood, despite large-scale habitat loss and fragmentation. I assessed the effects of long-term fragmentation on a subandean Avifauna in Colombia by comparing the occurrence of bird species in forest fragments isolated over 50–90 years with the original Avifauna. Prefragmentation bird composition was based on historical records and current species composition in continuous forest. The original Avifauna had approximately 139 forest species and 45 species of open habitats. Among forest species, 30% were currently extinct in fragmented forest and 4% were regionally extinct. At least 23 nonforest species colonized the region from the lowlands following deforestation. Species with small geographic ranges and those that were locally scarce or rare throughout their ranges were likely to be locally extinct. Forest raptors, terrestrial insectivores, and large frugivores were highly extinction prone, whereas nectarivores, small frugivores, and aerial insectivores were highly resilient; other guilds were intermediate. Antbirds (Formicariidae, Thamnophilidae), Cotingas, and, especially, Icterids were highly extinction prone. Large body size was not a determinant of vulnerability except among frugivores. Sixty-two percent of the species of special conservation concern were extinct in fragments. These results suggest that only large forest tracts will ensure the survival of a large proportion of subandean Avifaunas. Fragments of mature forest, however, may support a diverse Avifauna, including small populations of globally endangered species several decades after isolation. These fragments could play an important role in the restoration of local Avifaunas. A good understanding of the mechanisms that allow persistence in such fragments may prove essential for the conservation of those species for which no large tracts of suitable habitat remain. Resumen: El entendimiento que se tiene actualmente de los efectos de la fragmentacion de bosques esta basado en gran parte en sobre estudios de zonas templadas, Australia y tierras bajas del Neotropico. Por otra parte, las consecuencias de la fragmentacion antropogenica de bosques sobre las Avifaunas andinas son poco conocidas, a pesar de la perdida y fragmentacion de habitats a gran escala. Evalue los efectos de la fragmentacion a largo plazo sobre una Avifauna subandina en Colombia, comparando la Avifauna en fragmentos aislados por mas de 50–90 anos con la Avifauna original. La composicion original de la Avifauna se baso en registros historicos y la composicion actual en bosque continuo. La Avifauna original tenia aproximadamente 139 especies de bosque y 45 especies de habitats abiertos. El 30% de las aves de bosque se han extinguido en los bosques fragmentados y el 4% se han extinguido regionalmente. Al menos 23 especies de zonas abiertas colonizaron la region desde las tierras bajas siguiendo la deforestacion. Las especies con distribuciones geograficos restringidas, escasas localmente o raras a lo largo de su distribucion fueron propensas a extinguirse localmente. Las rapaces de interior de bosque, los insectivoros terrestres y los frugivoros grandes fueron altamente propensos a extinguirse; mientras que los nectarivoros, frugivoros pequenos e insectivoros aereos fueron resilientes; otros gremios fueron intermedios. Los hormigueros (Formicariidae y Thamnophilidae), las Cotingas y especialmente los Icteridos fueron altamente vulnerables. Tener un tamano corporal grande no fue un determinante de vulnerabilidad excepto entre los frugivoros. El sesenta y dos porciento de las especies de preocupacion especial para la conservacion se extinguieron en los bosques fragmentados. Estos resultados sugieren que solamente areas grandes de bosque continuo aseguraran la supervivencia de una proporcion grande de las Avifaunas subandinas. Sin embargo, los fragmentos de bosque maduro pueden soportar una Avifauna diversa que incluye poblaciones pequenas de especies amenazadas mundialmente despues de varias decadas de aislamiento. Estos fragmentos podrian jugar un papel importante en la restauracion de Avifaunas locales. Un buen entendimiento de los mecanismos que permiten la persistencia en fragmentos puede ser escencial para la conservacion de aquellas especies para las que no quedan remanentes de habitat grandes.
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composition changes in a subandean Avifauna after long term forest fragmentation
Conservation Biology, 1999Co-Authors: Luis Miguel RenjifoAbstract:: Current understanding of the effects of forest fragmentation is based largely on studies in temperate regions, Australia, and Neotropical lowlands. In contrast, the consequences of anthropogenic forest fragmentation for Andean Avifaunas are poorly understood, despite large-scale habitat loss and fragmentation. I assessed the effects of long-term fragmentation on a subandean Avifauna in Colombia by comparing the occurrence of bird species in forest fragments isolated over 50–90 years with the original Avifauna. Prefragmentation bird composition was based on historical records and current species composition in continuous forest. The original Avifauna had approximately 139 forest species and 45 species of open habitats. Among forest species, 30% were currently extinct in fragmented forest and 4% were regionally extinct. At least 23 nonforest species colonized the region from the lowlands following deforestation. Species with small geographic ranges and those that were locally scarce or rare throughout their ranges were likely to be locally extinct. Forest raptors, terrestrial insectivores, and large frugivores were highly extinction prone, whereas nectarivores, small frugivores, and aerial insectivores were highly resilient; other guilds were intermediate. Antbirds (Formicariidae, Thamnophilidae), Cotingas, and, especially, Icterids were highly extinction prone. Large body size was not a determinant of vulnerability except among frugivores. Sixty-two percent of the species of special conservation concern were extinct in fragments. These results suggest that only large forest tracts will ensure the survival of a large proportion of subandean Avifaunas. Fragments of mature forest, however, may support a diverse Avifauna, including small populations of globally endangered species several decades after isolation. These fragments could play an important role in the restoration of local Avifaunas. A good understanding of the mechanisms that allow persistence in such fragments may prove essential for the conservation of those species for which no large tracts of suitable habitat remain. Resumen: El entendimiento que se tiene actualmente de los efectos de la fragmentacion de bosques esta basado en gran parte en sobre estudios de zonas templadas, Australia y tierras bajas del Neotropico. Por otra parte, las consecuencias de la fragmentacion antropogenica de bosques sobre las Avifaunas andinas son poco conocidas, a pesar de la perdida y fragmentacion de habitats a gran escala. Evalue los efectos de la fragmentacion a largo plazo sobre una Avifauna subandina en Colombia, comparando la Avifauna en fragmentos aislados por mas de 50–90 anos con la Avifauna original. La composicion original de la Avifauna se baso en registros historicos y la composicion actual en bosque continuo. La Avifauna original tenia aproximadamente 139 especies de bosque y 45 especies de habitats abiertos. El 30% de las aves de bosque se han extinguido en los bosques fragmentados y el 4% se han extinguido regionalmente. Al menos 23 especies de zonas abiertas colonizaron la region desde las tierras bajas siguiendo la deforestacion. Las especies con distribuciones geograficos restringidas, escasas localmente o raras a lo largo de su distribucion fueron propensas a extinguirse localmente. Las rapaces de interior de bosque, los insectivoros terrestres y los frugivoros grandes fueron altamente propensos a extinguirse; mientras que los nectarivoros, frugivoros pequenos e insectivoros aereos fueron resilientes; otros gremios fueron intermedios. Los hormigueros (Formicariidae y Thamnophilidae), las Cotingas y especialmente los Icteridos fueron altamente vulnerables. Tener un tamano corporal grande no fue un determinante de vulnerabilidad excepto entre los frugivoros. El sesenta y dos porciento de las especies de preocupacion especial para la conservacion se extinguieron en los bosques fragmentados. Estos resultados sugieren que solamente areas grandes de bosque continuo aseguraran la supervivencia de una proporcion grande de las Avifaunas subandinas. Sin embargo, los fragmentos de bosque maduro pueden soportar una Avifauna diversa que incluye poblaciones pequenas de especies amenazadas mundialmente despues de varias decadas de aislamiento. Estos fragmentos podrian jugar un papel importante en la restauracion de Avifaunas locales. Un buen entendimiento de los mecanismos que permiten la persistencia en fragmentos puede ser escencial para la conservacion de aquellas especies para las que no quedan remanentes de habitat grandes.
Ralph Charles Mac Nally - One of the best experts on this subject based on the ideXlab platform.
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Climate-change-driven deterioration of the condition of floodplain forest and the future for the Avifauna
Global Ecology and Biogeography, 2013Co-Authors: Ralph Charles Mac Nally, Hania Lada, Shaun C. Cunningham, James Robertson Thomson, Erica FleishmanAbstract:Aim We used models of remotely sensed estimates of forest-stand condition (degree of die-back) with models of avian responses to stand condition to determine how the Avifauna responded to a 13-year drought, and how the Avifauna might respond to a predicted much warmer and drier climate in the next 60 years. Location Floodplain forests of the southern Murray–Darling Basin, Australia. Methods We selected 45 2-ha locations that spanned the full range of stand condition and conducted bird surveys and rapid assessments of breeding, which involved repeated measurements over the breeding season. These values were modelled as functions of stand condition and several other on-site predictors. We made hindcast estimates of the proportions of forest in different stand-condition classes. We developed a trajectory of change in these proportions under the regionally downscaled estimates of climate change under the A1F1 IPCC emission scenario, which were linked with patterns of change in drier, hotter extant forests. The hindcast and projected values were coupled with the results of the statistical models for the Avifauna to provide future projections for the Avifauna. Results Three Avifaunal variables (measures of abundance, effective species richness and total breeding score summed for all species) were strongly related to stand condition. Hindcast estimates based on the assumption of original good condition suggested that the response variables had declined by > 25% since 1750. Projected declines in the response variables from 2009 to 2070 were > 29%, while differences between 1750 and 2070 were > 58%. Conclusions Stand condition strongly influences birds, so that reliable estimates of Avifaunal change can be made by using remotely sensed estimates of stand condition. Given probable changes in forest condition under climate change, we project that the prospects for these Avifauna are dire under the A1F1 or more extreme emission scenarios.
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The Avifaunas of some fragmented, periurban, coastal woodlands in south-eastern Australia
Landscape and Urban Planning, 2005Co-Authors: Fiona Yeoman, Ralph Charles Mac NallyAbstract:Abstract Growth of urban centres world-wide has been so dramatic over the past 100–200 years that many natural habitats have been much altered around large cities. A threatened coastal plant community, Moonah Melaleuca lanceolata woodlands, has been largely destroyed and degraded over a long period by the growth of suburbs into the desirable coastal areas on the fringes of the two main cities of Vic., Australia (Melbourne and Geelong). Here, we describe the Avifaunas of 19 remnants of coastal Moonah woodland. The largest remnant is about 50 ha and this was used as a site for positioning ‘virtual’ remnants against which we could compare the Avifaunas of the more common size-range of real remnants (≤10 ha). Although remnant habitat structure differed consistently between virtual and real remnants, these differences were not sufficient to alter the native Avifaunas in constitution or bird densities. However, species richness was higher in 10 ha and in 2 ha remnants than in 1 ha remnants. Of seven landscape-context variables, only one influenced the Avifauna: species richness declined as the degree of urbanization increased (measured by roof-counts). Exotic bird species have not colonized the remnants to a great degree (four species [of 38 in total], 8% of total records).
Owen G Nichols - One of the best experts on this subject based on the ideXlab platform.
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long term trends in Avifaunal recolonisation of rehabilitated bauxite mines in the jarrah forest of south western australia
Forest Ecology and Management, 2000Co-Authors: Kyle N Armstrong, Owen G NicholsAbstract:Abstract Alcoa of Australia Limited rehabilitates areas in the jarrah forest of south-western Australia following bauxite mining. One of the aims of the company's rehabilitation programme is to re-establish the faunal communities which existed prior to mining. In the summers of 1981, 1987 and 1993, company biologists conducted bird surveys as part of a case study to determine the extent of Avifaunal recolonisation in representative mined areas. Analysis of monitoring data collected during the three surveys of the same areas showed considerable variation in the Avifaunal communities of three rehabilitated sites. Numbers of bird species and bird diversity in a site seeded with dense understorey continued to increase, and by 1993 all Avifaunal community parameters measured in this site were equal to or greater than those recorded in healthy unmined forest. Bird species numbers increased in a site given fresh topsoil but not seeded between 1981 and 1987; however, all parameters showed little further change by 1993. The oldest site, which was not seeded or given fresh topsoil, showed the greatest degree of change. In 1981, it supported only one bird species, but by 1993 all bird community parameters were similar to those recorded in the site which received fresh topsoil but no seed. Species composition of all rehabilitated sites' Avifauna also changed. The similarity of bird community composition increased over time. By 1993, the healthy forest communities were more similar to those of some rehabilitated sites than to those of forest degraded by dieback disease. The study demonstrated that development of the vegetation community is a key factor controlling the composition of bird communities in rehabilitated mine sites. Recommendations are given to further promote Avifaunal recolonisation following mining.
Alison Doley - One of the best experts on this subject based on the ideXlab platform.
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The birds of “Koobabbie” in the northern wheatbelt of Western Australia (1987–2011) and the contribution of the farm to conservation of the region’s Avifauna
Pacific Conservation Biology, 2013Co-Authors: Denis A. Saunders, Alison DoleyAbstract:The Avifauna of Koobabbie, a 7 173 ha wheat and sheep property in the northern wheatbelt of Western Australia with 41.5% the property under remnant native vegetation, was monitored on a weekly basis from May 1987 to December 2011. Recorded during this period were 131 species, comprising 55 residents, seven regular visitors, 14 irregular visitors and 55 vagrants. Fifteen species declined over the 25 years, with one species being extirpated and two species increased. Two other species increased until early this century and then declined. The Avifauna of Koobabbie was compared with that of the Northern Agricultural Catchment Council region, in the middle of which region the property is located. Koobabbie comprehensively represented the region’s Avifauna and contributed significantly to conservation of the region’s Avifauna. This study demonstrates the importance of continuous long-term datasets from a single locality. The need to set up a network of such monitoring sites over much of Australia in order to provide information for management of natural resources is discussed.
Kyle N Armstrong - One of the best experts on this subject based on the ideXlab platform.
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long term trends in Avifaunal recolonisation of rehabilitated bauxite mines in the jarrah forest of south western australia
Forest Ecology and Management, 2000Co-Authors: Kyle N Armstrong, Owen G NicholsAbstract:Abstract Alcoa of Australia Limited rehabilitates areas in the jarrah forest of south-western Australia following bauxite mining. One of the aims of the company's rehabilitation programme is to re-establish the faunal communities which existed prior to mining. In the summers of 1981, 1987 and 1993, company biologists conducted bird surveys as part of a case study to determine the extent of Avifaunal recolonisation in representative mined areas. Analysis of monitoring data collected during the three surveys of the same areas showed considerable variation in the Avifaunal communities of three rehabilitated sites. Numbers of bird species and bird diversity in a site seeded with dense understorey continued to increase, and by 1993 all Avifaunal community parameters measured in this site were equal to or greater than those recorded in healthy unmined forest. Bird species numbers increased in a site given fresh topsoil but not seeded between 1981 and 1987; however, all parameters showed little further change by 1993. The oldest site, which was not seeded or given fresh topsoil, showed the greatest degree of change. In 1981, it supported only one bird species, but by 1993 all bird community parameters were similar to those recorded in the site which received fresh topsoil but no seed. Species composition of all rehabilitated sites' Avifauna also changed. The similarity of bird community composition increased over time. By 1993, the healthy forest communities were more similar to those of some rehabilitated sites than to those of forest degraded by dieback disease. The study demonstrated that development of the vegetation community is a key factor controlling the composition of bird communities in rehabilitated mine sites. Recommendations are given to further promote Avifaunal recolonisation following mining.
