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Since European settlement, the woodlands and associated habitats, especially in the temperate zones of Australia, have been extensively cleared and converted to arable land and pastures. Much of the remaining vegetation in the agricultural zone occurs as small isolated patches prone to disturbance and degradation. Apart from habitat loss and fragmentation, altered fire regimes, periods of intense drought, and the introduction of exotic plants and animals, have contributed to the deterioration of most of the natural habitats across Australia, with a negative impact on the native wildlife, including birds. Many woodland bird species have undergone widespread declines, culminating in some local or even regional extinctions. In the mallee woodlands of south-east Australia two closely related species of whistlers (fam. Pachycephalidae) — Red-lored Whistler Pachycephala rufogularis and Gilbert’s Whistler P. inornata — have overlapping ranges, and in some areas they co-exist. These two species are morphologically and ecologically similar. However, despite the similarities, P. rufogularis has undergone greater declines in distribution and abundance than P. inornata. The ecology of these two species is poorly known, which renders adequate management impracticable. The major objectives of this thesis were to determine the key habitat requirements for the two species, to determine their habitat use, and to document the ecology and behaviour of the two species, particularly their foraging, and intra- and interspecific interactions. A sound knowledge of the ecology of the two species is needed to underpin appropriate actions for their management and conservation. Morphological features were measured from skins of P. rufogularis and P. inornata in the South Australian Museum collection, and from captured live birds, to detect if any aspect of the morphology could indicate possible niche partitioning between the two species. Also, the use of biometry as a tool for separating the sexes for P. rufogularis, for determining the species of the uncoloured immature birds and for sexing immatures, was evaluated. No morphological feature suggested niche partitioning. The biometry did not prove a very reliable tool for distinguishing sexes in adult P. rufogularis, but reliably identified the species of the uncoloured immatures. Sexing immatures based on biometrical data alone was not possible. Research was conducted in two main South Australian parks: Gluepot Reserve and Ngarkat Conservation Park. Ecological and behavioural data for P. rufogularis and P. inornata were collected by observing marked (colour-banded and radio-tagged) and unmarked individual birds of both species and sexes, over a two-year period from June 2004 to May 2006. The home ranges of P. rufogularis and P. inornata were determined by tracking the movements of birds in the landscape. Pachycephala rufogularis had much larger home ranges than P. inornata, especially when breeding. The striking differences in home range size between the two ecologically similar species might be related to differences in site fidelity. Pachycephala rufogularis at Gluepot was sedentary, being detected in the same locations throughout the year, and over several years. On the contrary, P. inornata generally showed poor site fidelity, being more mobile, and shifting home ranges between and within seasons. In the field the two species were segregated by habitat. Pachycephala rufogularis and P. inornata showed different habitat preferences, even in areas where they did not co-occur. Pachycephala rufogularis favoured low mallee with Triodia on sand dunes, while P. inornata favoured tall mallee with sparse shrub understorey in interdunes, but also other habitats, such as prickly Acacia thickets and Casuarina woodlands. However, both species used the mallee- Triodia with Callitris vegetation type. The key to coexistence in this habitat was a behavioural one, P. inornata acting as a subordinate species. Pachycephala rufogularis had strict habitat requirements, with the presence of Triodia being critical for the presence of the species. In contrast, P. inornata was more flexible in its habitat requirements, and used a broader range of vegetation types, being more of a habitat generalist. The investigation of habitat use from both a spatial and temporal perspective confirmed that both species actively selected habitat, and that the habitats they selected differed. The core areas of home ranges predominantly contained the preferred habitat for both species. In both species, core areas of home ranges of breeding individuals (where generally the nests were placed) contained preferred habitat in higher proportion than core areas of non-breeding birds. This suggests that during breeding, both species are more restricted to, and/or use more intensely the preferred habitat than when not breeding. The foraging behaviour did not differ consistently between the two species, both capturing insects mostly by snatching in canopy foliage, and also by gleaning on the vegetation, at different heights. However, the two species were already segregated by habitat. Thus the resource partitioning occurred spatially, at the macrohabitat level. In the instances when individuals of both species foraged in the same area and used the same resources, resource partitioning occurred at a temporal scale. Both species were generalists in foraging; therefore, a presumed foraging specialisation as a possible factor related to the decline of P. rufogularis was ruled out. Pachycephala rufogularis and P. inornata are unlikely to be competitors. Support for this argument came from the situation at Ngarkat, where P. inornata was absent. Despite this, P. rufogularis did not use a broader range of vegetation types in Ngarkat, as would be expected under ‘competitive release’. Instead the species maintained strict habitat requirements, specializing virtually on a single vegetation type. The rigid habitat requirements of P. rufogularis, together with its sedentary nature, render this species vulnerable to disturbances, such as wildfires. On the other hand, the apparent flexibility in habitat requirements and greater mobility may explain why P. inornata has been more successful than its sibling species. The information on habitat requirements, preference and use, and also on home ranges of P. rufogularis and P. inornata provided in this study should be included in future habitat suitability models and predictive models for these species, which will assist in their management. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1374821 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2009

Since European settlement, the woodlands and associated habitats, especially in the temperate zones of Australia, have been extensively cleared and converted to arable land and pastures. Much of the remaining vegetation in the agricultural zone occurs as small isolated patches prone to disturbance and degradation. Apart from habitat loss and fragmentation, altered fire regimes, periods of intense drought, and the introduction of exotic plants and animals, have contributed to the deterioration of most of the natural habitats across Australia, with a negative impact on the native wildlife, including birds. Many woodland bird species have undergone widespread declines, culminating in some local or even regional extinctions. In the mallee woodlands of south-east Australia two closely related species of whistlers (fam. Pachycephalidae) — Red-lored Whistler Pachycephala rufogularis and Gilbert’s Whistler P. inornata — have overlapping ranges, and in some areas they co-exist. These two species are morphologically and ecologically similar. However, despite the similarities, P. rufogularis has undergone greater declines in distribution and abundance than P. inornata. The ecology of these two species is poorly known, which renders adequate management impracticable. The major objectives of this thesis were to determine the key habitat requirements for the two species, to determine their habitat use, and to document the ecology and behaviour of the two species, particularly their foraging, and intra- and interspecific interactions. A sound knowledge of the ecology of the two species is needed to underpin appropriate actions for their management and conservation. Morphological features were measured from skins of P. rufogularis and P. inornata in the South Australian Museum collection, and from captured live birds, to detect if any aspect of the morphology could indicate possible niche partitioning between the two species. Also, the use of biometry as a tool for separating the sexes for P. rufogularis, for determining the species of the uncoloured immature birds and for sexing immatures, was evaluated. No morphological feature suggested niche partitioning. The biometry did not prove a very reliable tool for distinguishing sexes in adult P. rufogularis, but reliably identified the species of the uncoloured immatures. Sexing immatures based on biometrical data alone was not possible. Research was conducted in two main South Australian parks: Gluepot Reserve and Ngarkat Conservation Park. Ecological and behavioural data for P. rufogularis and P. inornata were collected by observing marked (colour-banded and radio-tagged) and unmarked individual birds of both species and sexes, over a two-year period from June 2004 to May 2006. The home ranges of P. rufogularis and P. inornata were determined by tracking the movements of birds in the landscape. Pachycephala rufogularis had much larger home ranges than P. inornata, especially when breeding. The striking differences in home range size between the two ecologically similar species might be related to differences in site fidelity. Pachycephala rufogularis at Gluepot was sedentary, being detected in the same locations throughout the year, and over several years. On the contrary, P. inornata generally showed poor site fidelity, being more mobile, and shifting home ranges between and within seasons. In the field the two species were segregated by habitat. Pachycephala rufogularis and P. inornata showed different habitat preferences, even in areas where they did not co-occur. Pachycephala rufogularis favoured low mallee with Triodia on sand dunes, while P. inornata favoured tall mallee with sparse shrub understorey in interdunes, but also other habitats, such as prickly Acacia thickets and Casuarina woodlands. However, both species used the mallee- Triodia with Callitris vegetation type. The key to coexistence in this habitat was a behavioural one, P. inornata acting as a subordinate species. Pachycephala rufogularis had strict habitat requirements, with the presence of Triodia being critical for the presence of the species. In contrast, P. inornata was more flexible in its habitat requirements, and used a broader range of vegetation types, being more of a habitat generalist. The investigation of habitat use from both a spatial and temporal perspective confirmed that both species actively selected habitat, and that the habitats they selected differed. The core areas of home ranges predominantly contained the preferred habitat for both species. In both species, core areas of home ranges of breeding individuals (where generally the nests were placed) contained preferred habitat in higher proportion than core areas of non-breeding birds. This suggests that during breeding, both species are more restricted to, and/or use more intensely the preferred habitat than when not breeding. The foraging behaviour did not differ consistently between the two species, both capturing insects mostly by snatching in canopy foliage, and also by gleaning on the vegetation, at different heights. However, the two species were already segregated by habitat. Thus the resource partitioning occurred spatially, at the macrohabitat level. In the instances when individuals of both species foraged in the same area and used the same resources, resource partitioning occurred at a temporal scale. Both species were generalists in foraging; therefore, a presumed foraging specialisation as a possible factor related to the decline of P. rufogularis was ruled out. Pachycephala rufogularis and P. inornata are unlikely to be competitors. Support for this argument came from the situation at Ngarkat, where P. inornata was absent. Despite this, P. rufogularis did not use a broader range of vegetation types in Ngarkat, as would be expected under ‘competitive release’. Instead the species maintained strict habitat requirements, specializing virtually on a single vegetation type. The rigid habitat requirements of P. rufogularis, together with its sedentary nature, render this species vulnerable to disturbances, such as wildfires. On the other hand, the apparent flexibility in habitat requirements and greater mobility may explain why P. inornata has been more successful than its sibling species. The information on habitat requirements, preference and use, and also on home ranges of P. rufogularis and P. inornata provided in this study should be included in future habitat suitability models and predictive models for these species, which will assist in their management. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1374821 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2009

Agricultural environments are critical to the conservation of biota throughout the world. This is due both to the limited extent of current reserve systems and the large, and still expanding, proportion of terrestrial environments already dominated by agricultural land-uses. Consequently, there is a growing call from scientists around the world for the need to maximise the conservation value of agricultural environments. Efforts to identify key influences on the conservation status of fauna in agricultural landscapes have taken complementary approaches. Many studies have focussed on the role of remnant or semi-natural vegetation, and emphasised the influence on biota of spatial patterns in the landscape. Others have recognised that many species use diverse ‘countryside’ elements (matrix habitats) within farmland, and emphasise the benefits of landscape heterogeneity for conservation. Here, these research themes have been combined. This study takes a whole-of-landscape approach to investigating how landscape pattern and countryside heterogeneity influence the occurrence of birds in agricultural environments. Birds were sampled in 27 agricultural mosaics, each 1 km x 1 km in size (100 ha), in Gippsland, south-eastern Australia. Mosaics were selected to incorporate variation in two landscape properties: the cover of native vegetation, and richness of different types of element (i.e. land-uses/vegetation types). In each mosaic, 15 fixed sampling locations were stratified among seven different elements in proportion to their cover in the mosaic: native vegetation, linear vegetation, tree plantation, scattered paddock trees, pasture, wetlands and farm dams. Six point counts of birds were undertaken at all sample points in each mosaic: three each in the breeding and non-breeding months of a one-year period (October 2004 – August 2005). Independent measures of the composition, configuration, and heterogeneity of elements in the mosaic had differing effects on the richness of bird species recorded in these same mosaics. Sub-groups of birds based on habitat requirements responded most strongly to the extent of preferred element types in mosaics. Woodland birds (those of greatest conservation concern in farmland environments in Australia) were richer in mosaics with higher cover of native vegetation while open-tolerant species responded to the extent of scattered trees. In contrast, for total species richness, mosaic heterogeneity (richness of element types) and landscape context (cover of native vegetation in surrounding area) had the greatest influence. Mosaic structural properties also influenced the composition of entire bird assemblages in study mosaics. Avifaunal composition showed systematic variation along two main gradients which were readily interpreted in relation to landscape properties: 1) a gradient in the cover of wooded vegetation and, 2) the proportional composition of vegetation types in the mosaic. These gradients represent common trajectories of landscape modification associated with agricultural development: namely, the removal of wooded vegetation and the replacement of native species with exotic vegetation (e.g. crops and plantations). Species possessing different characteristics in relation to three avian life-history traits (nest type, feeding guild and clutch size) varied significantly in their position along these gradients of landscape modification. Species with different nesting requirements showed a strong relationship with the gradient in wooded vegetation cover while species belonging to different feeding guilds were influenced by the gradient defined by the replacement of native vegetation with exotic species. More bird species were recorded in native vegetation than in any other type of element sampled in this study. Nevertheless, most countryside elements had value for many species; particularly structurally complex elements such as scattered trees and tree plantation. Further, each type of landscape element contained different bird assemblages. Species that were recorded in a greater number of different types of landscape element were also recorded in more mosaics. This was true for all species and for woodland birds, and indicates that species that can use a greater range of countryside elements may have an increased tolerance of future landscape modification. The richness of woodland species at survey sites in different elements was influenced by features of the mosaic in which they occurred. Notably, the richness of woodland bird species recorded at sites in scattered trees and pasture increased with a greater cover of native vegetation in the overall mosaic. Of the overall pool of woodland bird species documented in the broader study region, 35% of species were not recorded in the agricultural mosaics sampled here. While many of these species were uncommon in the study area, or were associated with vegetation communities infrequently sampled in mosaics, this shows that conservation efforts in agricultural landscapes will not be appropriate for all species. For those woodland species that were recorded, measures of the extent of wooded vegetation cover had a strong, positive influence on the frequency of occurrence of individual species in mosaics. Thus, individual species of woodland bird occurred more frequently in mosaics with a greater cover of wooded vegetation. Nine woodland species showed a stronger response to measures of vegetation cover that included tree plantation and/or scattered trees than to the cover of native vegetation alone. For these species, structurally complex countryside elements provide valuable supplementary habitat at the landscape scale. Results of this study show that landscape properties influence the occurrence of birds in agricultural mosaics. The extent of cover of element types, particularly native vegetation, had the strongest influence on all measures of bird occurrence in mosaics. Thus, native vegetation is vital for the persistence of birds in farmland landscapes and is the primary element on which conservation efforts in these environments depend. Nevertheless, with careful management, countryside elements may provide additional conservation benefits for many bird species. Countryside elements made an important contribution to landscape heterogeneity, the landscape property with greatest influence on overall bird richness in mosaics. Countryside elements also increased the structural complexity of cleared agricultural land, and so have the capacity to enhance connectivity in fragmented landscapes. A focus on these factors (landscape heterogeneity and structural complexity) will provide the greatest opportunities for using countryside elements to increase the conservation value of farmland environments for native fauna. The relatively small scale of this study indicates that the cumulative effect of even small elements in farm mosaics contributes to the structural properties of entire landscapes. Critically, this emphasises the important contribution that individual landholders can make to nature conservation in agricultural environments.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

Quoi de plus naturel qu’une clôture ? Parmi les images d’Epinal qui nous viennent spontanément à l’esprit, le bocage avec ses haies bien ordonnées, évoque une relation apaisée, rationnelle, arcadienne avec une nature nourricière et bienveillante. Pourtant, la prolifération des clôtures en milieu rural depuis un siècle a suscité la curiosité de nombreux chercheurs dans des disciplines variées. Qu’il s’agisse de protéger la nature de dégradations engendrées par les populations humaines - dans le cas d’espaces protégés -, ou à l’inverse de protéger les humains contre des dangers « naturels » - comme dans le cas de la prévention routière, ces clôtures semblent répondre à une nécessité absolue de ségrégation spatiale entre les hommes et la nature : Quoi de moins naturel qu’une clôture ? Vu sous cet angle, le conflit politico-environnemental engendré par la propagation récente des engrillagements forestiers en Sologne reflète assez bien l’ambiguïté de nos perceptions vis-à-vis du caractère naturel ou non de ces clôtures. La Sologne est une région naturelle Française couvrant près de 500 000 hectares délimitée au nord par la vallée de la Loire et au sud par la vallée du Cher. Fruit d’une occupation humaine attestée depuis le XIe siècle, conjuguée à des contraintes écologiques spécifiques, le paysage Solognot est aujourd’hui caractérisé par son couvert boisé important (environ 50% de la surface) et ses populations importantes de grand gibier, qui entretiennent la longue réputation cynégétique de cette région ; la propriété privée y est largement majoritaire (plus de 90% de la surface forestière). En 2012, une agitation médiatique (film, articles de presse, sites internet) cristallisent un conflit environnemental latente, faisant intervenir des éléments écologiques – les effets supposés bénéfiques ou néfastes de ces engrillagements sur la grande faune, mais aussi politiques – la nécessité de réglementer les engrillagements, et culturels - la sauvegarde du « paysage Solognot ». Afin d’analyser ce conflit, une approche interdisciplinaire de type Political Ecology a été menée, mêlant travail d’enquête auprès de la population et étude du fonctionnement écologique des espaces engrillagés. Ces travaux ont montré que les engrillagements modifient la répartition spatiale des cerfs. La recherche d’effets cascades sur les oiseaux forestiers - résultants des surdensités locales de cerfs en espace engrillagé - n’a cependant pas mis en évidence d’effet négatif. A partir des enquêtes, il apparaît que le conflit est pluridimensionnel et que l’aspect écologique – bien réel – ne suffit pas à lui seul pour comprendre l’enjeu de ce débat au sujet des engrillagements. Ces résultats génèrent une réflexion sur la complexité des conflits environnementaux, et la nécessité d’envisager ces conflits sous des angles différents. Cela implique d’utiliser des outils et des approches issues de plusieurs disciplines, mais aussi et surtout de parvenir à mettre en résonance le matériel hétérogène ainsi obtenu, afin de proposer une approche multifacette mais cohérente. Dans ce cas d’étude, les résultats sur les effets cascades se sont par exemple révélés extrêmement marginaux, alors qu’une étude parallèle sur le comportement du sanglier en milieu engrillagé aurait probablement été très pertinente. Cela amène plus largement à réfléchir sur le « cadrage » des problèmes environnementaux, et sur les choix conscients ou non que nous faisons lorsque nous décrivons une situation comme problématique pour « la nature ». Plus généralement, ces résultats incitent à (re)placer le politique au cœur de nos réflexions sur ce qu’est la « nature », y compris dans la façon dont nous écologues posons nos questions de recherches. / What could be more natural than a fence? Among the traditional images in our collective heritage, a pastoral landscape with well maintained hedges evokes a calm, rational, Arcadian relationship between man and a benevolent, sustaining ature. Yet the century-long proliferation of fences in our rural landscapes has attracted the curiosity of numerous researchers from a variety of disciplines. Whether the goal is to protect nature from the degradations caused by human populations - as in the case of natural protected areas, or inversely, to protect humans from “natural” dangers – as in the case of accident prevention and road safety, fences seem to respond to a primordial necessity to segregate man and nature in space: What could be less natural than a fence? With this in mind, the political/environmental conflict over the recent propagation of forest fences in Sologne reflects quite well the ambiguity of how we perceive such fences – or they “natural” or not? The Sologne is an officially designated “natural region” in France. It extends over nearly 500,000 hectares bordered on the North by the Loire valley and on the South by the Cher valley. The Sologne landscape is the fruit of human occupation, certain since the XI century, combined with specific ecological constraints. Today, Sologne is characterized by extensive forest cover (around 50% of the surface area) and by large populations of big game animals, maintaining the region’s a long history of hunting. Furthermore, land ownership in Sologne is mainly private and more than 90% of the forested area is in private holdings. In 2012, some media excitement (film, newspaper articles, internet sites) crystallized an environmental conflict calling on ecological arguments – the supposed beneficial or detrimental effects of the fencing networks on big game, but also on political arguments – the need to regulate these networks, and on cultural arguments – preserving the Sologne landscape. In order to disentangle the structural lines of this conflict, we applied an interdisciplinary, Political Ecology approach; we combined opinion polls among the inhabitants with the study of ecological functions within the fenced zones. We observed that fences induced modifications of deer habitat use. However, our investigations into a possible cascade effect on forest birds resulting from localized deer over-population in fenced areas revealed no evidence of any negative impact. From our opinion polls, we found that the conflict seems to be multi-dimensional and that the ecological aspect – whose existence is indeed supported by fact – is not sufficient alone to understand what is at stake in this fencing dispute. Our results highlight the complexity of environmental conflicts, and the importance of viewing these conflicts from many different angles. Apprehending this complexity implies using tools and approaches from several different disciplines, but also – and above all – making the heterogeneous results obtained resonate together, in order to propose a coherent, multi-facetted approach. In this study for example, the results obtained for potential cascade effects on birds were extremely marginal, whereas a parallel study on wild boar behavior patterns in an environment with a fencing network would probably have been very pertinent. This leads us to the broader question of the “framework” of environmental problems and to the question of the choices we make – whether consciously or not – when we describe a situation as detrimental to “Nature”. More generally, the results from this study encourage us to put politics (back) into the center of our reflections surrounding the question: What is nature? – and to keep this in mind when we as ecologists define our research hypotheses.