Monitoring the effects of climate change on the rainforest birds of eastern Australia

Escalating anthropogenic impacts on tropical biodiversity have amplified the vulnerability of endemic species. Selective harvesting of species is one of the major threats to birds and mammal species in the tropics. Many indigenous cultures, however, have long established cultural associations with certain species. The hunting and trade of species have been mainly for subsistence and socio-cultural ties within their communities. However, contemporary threats associated with human population increase from within such societies and externally driven demand such as wildlife trafficking exacerbate the pressure particularly for vulnerable species. Threats to endemic tropical species are not isolated to one but often synergies between many factors simultaneously affecting changes to species distribution. In addition to immediate anthropogenic impacts such as population pressure exerted on species numbers and species habitats, there is growing evidence that demonstrates that climate change is causing shifts in species distribution. Such cases have been demonstrated in tropical island montane forests. The island of New Guinea is the largest tropical island in the world and accommodates the third largest tropical rainforests. New Guinea has over 600 bird species (195 endemic), but some species are under threat from unsustainable hunting practices, climate change, and landscape modification. The central highlands is one of the most populous areas and has undergone thousands of years of human modification. The biodiversity of the island of New Guinea remains one of the understudied sites in the world. Looming threats necessitate an assessment of the vulnerability of species important to subsistence and culture. This thesis addresses the need for further understanding of the vulnerability of species to anthropogenic impacts associated with hunting and trade and the effects of climate change on endemic montane species. The thesis begins by improving the contemporary understanding of trade of bird species in the central highlands (large scale) of Papua New Guinea. The contemporary costs of species traded were delineated from this study and compared to the known records over 40 years. Next, case study sites (fine scale) were conducted to understand how rural forest communities hunt and trade wildlife and the social nuances that affect their choice and locality of hunting activities. The study then uses species identified from trade and hunting to conduct a vulnerability assessment of species most at risk from selective harvesting. This assessment may also serve as a guide to conservation efforts in the central highlands. Finally, a rare endemic species, Paradisornis rudolphi (Blue Bird of Paradise) was selected from the vulnerability assessment to make predictions of its distribution change due to climate change. Overall, this thesis demonstrates the importance of applying an interdisciplinary approach that is relevant to the region, context of culture, society, and conservation. This study suggests that vulnerable species used in culture are also at risk from effects of climate change. This information, in addition to other extrinsic factors such as land use change (not studied), is vital for conservation of the endemic montane species, as well as the persistence of cultural diversity in New Guinea. There are limitations to this study which include the lack of a better climate model for Papua New Guinea. The species distribution model should serve as a conservative prediction of the outcome of a rare endemic species. However, even with a conservative approach, there is indication of the need for proactive approaches at the rural and national levels. A way forward would be to consider means of income generation that also support the conservation of species, such as eco-tourism. At the policy level, there is a need to revise the policy to reflect species management and the enforcement of monitoring of unlawful trade particularly those that may be destined for international markets.

Freshwater ecosystems represent hotspots for the world’s total diversity and human well-being. However, they are also subjected to threats across the globe as a result of localised human activities, broad scale catchment clearance, climate change and invasive species. The increased degradation of freshwater habitats and their ecological functions as a consequence of these threats, at local and global scales, has led to significant freshwater problems for human existence and the world’s biodiversity. There is growing evidence that the loss of biodiversity is one of the most complex environmental issues facing the world; however, the importance of understanding species distribution patterns and the ecological differentiation among species that are reflected as species-specific responses or tolerances to environmental drivers is less well understood. In particular, when a morphological approach is used as a taxonomic tool for investigating species diversity and species level responses to environmental drivers, the diversity of responses hidden within species complexes may not be realized, and the conclusion of generality may mask specific cryptic species responses. In South-East Queensland, Australia, European occupation since the mid 1800’s has seen large scale clearing of native vegetation along streams and rivers in nearly all catchments. As a consequence of this land-use change catchment hydrology has been substantially altered, which, combined with the presence of dams and weirs, has resulted in a decline in water quality of streams in some catchments, which is of growing concern for conservation of species biodiversity. This study aimed to explore cryptic diversity in two species complexes of freshwater aytid shrimps common in South-East Queensland and elucidate species level responses to environmental variation that could explain their spatial distribution. This broad aim was met through three specific studies. First, using regional scale data of cryptic species diversity and water quality, the importance of species-specific responses to environmental conditions in determining spatial distribution patterns and environmental relationships of cryptic species in the Caridina indistincta and Paratya australiensis species complexes was examined. To accomplish this aim, DNA sequences were used to identify shrimp specimens from 89 sites in 17 catchments spanning the study area. In addition, an assessment of eight morphological traits was used to test whether these cryptic species could be morphologically identified. Use of these eight traits did allow species level identification, at least in South-East Queensland. However, caution is suggested in the use of these morphological traits for recognising species, due to the probability of morphological plasticity within a species across broad spatial scales. Ordination analysis of presence-absence data showed that the five cryptic species within the two species complexes showed spatially distinct distributions across streams in SEQ, with each cryptic species displaying different relationships with individual environmental variables. For species in the Caridina indistincta complex, C. indistincta sp. B was significantly associated with elevation, C. indistincta sp. D was significantly correlated with dissolved oxygen range, whilst, individuals of C. indistincta sp. A were negatively associated with elevation and dissolved oxygen range. This may indicate that C. indistincta sp. A tended to inhabit sites with low elevation and perhaps having a higher tolerance to a low range of dissolved oxygen. For the Paratya australiensis species complex, P. australiensis lineage 4 and 6 showed significant correlations with elevation and conductivity, respectively. The second broad aim of the study was to explore these spatial patterns at smaller geographical scales and with greater detail about water quality to understand and quantify the fundamental environmental factors (e.g., physical chemical water parameters and concentrations of heavy metals) that are potentially shaping the current distribution patterns and abundance of cryptic species within the two species complexes. To explore this aim, sediment samples from 22 sites in 13 catchments in SEQ were analysed to determine concentrations (mg/kg dry weight) of 11 heavy metals. Additionally, a number of water quality variables were measured in situ, including: elevation, stream width, stream temperature, dissolved oxygen, conductivity, pH, total dissolved solids, and turbidity. Also, a water sample was taken from each site for laboratory analysis of: Ammonium nitrogen (NH4-N), Dissolved oxidized nitrogen (Nitrate+Nitrite) (NOX-N), Total nitrogen (TN), Total kjeldahl nitrogen (TKN), Total kjeldahl phosphorus (TKP), Orthophosphate-P (PO4-P). Shrimps were collected from each site and identified to species using both morphology and DNA sequencing. The morphological identification of each adult individual (except juveniles which were genetically analysed) was used as a measure of absolute abundance and the genetic ‘checking’ of a set number of individuals in each sample was used to compute relative abundance. Redundancy analysis (RDA) showed that the spatial distribution and absolute and relative abundance of C. indistincta sp. D and sp. B were significantly positively influenced by elevation, while the relative abundance of P. australiensis Lin.6 was significantly positively affected by the concentration of manganese (Mn). Stream Total nitrogen (TN) was significantly positive driver of the spatial distribution and relative abundance of C. indistincta sp. A, while Orthophosphate-P (PO4-P) was significantly positive driver for the absolute and relative abundance of this species. Further analysis, this study confirms that P. australiensis Lin.6 was more tolerant of heavy metal concentrations compared with other cryptic species, as its distribution and absolute and relative abundance were significantly positively correlated with the concentrations of manganese, iron and cobalt. In contrast, C. indistincta sp. A was more sensitive to these metals than other study species. These results demonstrated that cryptic species of freshwater atyid shrimps of the C. indistincta and P. australiensis species complexes were different in their environmental requirements. As well, the cryptic species of both complexes were identified to have different associations with heavy metal concentrations, indicating that these species were different in their tolerance to toxicants. Finally, the third aim of the study was to further examine the differences in sensitivity to heavy metals (Copper and Zinc) among cryptic species of the two study complexes experimentally in the laboratory. Two cryptic species of each complex were used as study species, C. indistincta sp. A and sp. D and P. australiensis Lin.4 and Lin.6. The field studies showed differences among these species in their correlations with metal concentrations, and therefore they were seen as good candidate species for testing differences in the sensitivity to metal toxicants. Each cryptic species was exposed to six concentrations of each metal Cu or Zn using an acute (96-h) toxicity test. The results from this study were generally showed contrasting correlation between species and heavy metals; P. australiensis Lin.6 was the most tolerant species to both study metals, while C. indistincta sp. A was more sensitive to copper, and C. indistincta sp. D was more sensitive to Zn compared with the other tested species. Furthermore, the exposure of individuals of each species to the heavy metals caused changes in both their behaviour and their colour during exposure time. Overall, this study has shown cryptic species within broad species complexes can vary in their spatial distribution and their tolerance and response to water quality parameters. This highlights the advantage of using analyses of biotic and abiotic variables for ecological management and biodiversity conservation and the need to understand true species diversity when looking at species level responses to environmental degradation.

Montane birds face significant threats from a warming climate, so determining the environmental factors that most strongly influence the composition of such assemblages is of critical conservation importance. Changes in temperature and other environmental conditions along elevational gradients are known to influence the species richness and abundance of bird assemblages occupying mountains. However, the role of species‐specific traits in mediating the responses of bird species to changing conditions remains poorly understood. We aimed to determine whether different bird species responded differently to changing environmental conditions in a relatively understudied biodiversity hotspot in subtropical rainforest on the east coast of Australia. We examined patterns in avian species richness and abundance along two rainforest elevational gradients using monthly point counts between September 2015 and October 2016. Environmental data on temperature, wetness, canopy cover and canopy height were collected simultaneously, and trait information on body size and feeding guild membership for each bird species was obtained from the Handbook of Australian, New Zealand and Antarctic Birds. We used a generalized linear mixed modelling (GLMM) framework to determine the drivers of species richness and abundance and to quantify species’ trait–environment interactions. GLMMs indicated that temperature alone was significantly positively correlated with species richness and abundance. Species richness declined with increasing elevation. When modelling abundance, we found that feeding guild membership did not significantly affect species’ responses to environmental conditions. In contrast, the predicted abundance of a species was found to depend on its body size, due to significant positive interactions between this trait, temperature and canopy cover. Our findings indicate that large‐bodied birds are likely to increase in abundance more rapidly than small‐bodied birds with continued climatic warming. These results underline the importance of temperature as a driving factor of avian community assembly along environmental gradients.

Many montane avian communities are likely to be impacted negatively by future climate change. The ability to monitor these ecosystems effectively is therefore a priority. As species are expected to track their preferred climates by moving upwards in elevation, using indicator species of elevations has been suggested as a climate change monitoring strategy and has been explored for a variety of taxa in eastern Australia. Birds have great potential as vertebrate indicators due to their familiarity, detectability, and well known life histories. We used automated recording units (ARUs) and point counts to sample the avifauna along two elevational gradients in subtropical rainforest in north-eastern New South Wales, Australia. We used the indicator value protocol to identify avian indicators of elevation suitable for long-term monitoring. Pairs of species were more reliable than single species as indicators, and searching for indicators of elevational ranges (e.g. 300–500m) proved more effective than looking for indicators of single elevations (e.g. 300m). Point counts and ARUs were equally effective at determining indicators of elevations and ARUs performed particularly well in spring. We present avian indicator sets of lowland and highland sites, which provide a baseline for future monitoring of the effects of climate change on the region’s avifauna. The methodology employed here is broadly suitable for similar studies elsewhere. We propose that the use of ARUs to identify indicator species of elevations is an effective strategy for monitoring the effects of climate change on montane avian communities worldwide.

Assessing the vulnerability of Thailand's forest birds to global change

Species diversity and community composition of birds change rapidly along elevational gradients in Costa Rica. Such changes are of interest ecologically and illustrate the value of protecting continuous gradients of forest. We used mist nets and point counts to sample birds along an elevational gradient on the northeastern Caribbean slope of the Cordillera Central in Costa Rica. Sites included mature tropical wet forest (50 m); tropical wet, cool transition forest (500 m); tropical premontane rain forest (1,000 m); and tropical lower montane rain forest (1,500 and 2,000 m). We recorded 261 species from 40 families, including 168 species captured in mist nets (7,312 captures) and 226 detected during point counts (17,071 observations). The sample included 40 threatened species, 56 elevational migrants, and 22 latitudinal migrants. Species richness (based on rarefaction analyses) changed little from 50 to 1,000 m but was lower at 1,500 and 2,000 m. Mist nets and point counts often provided similar views of community structure among sites based on relative importance of difference categories of species (e.g. migrant status, trophic status). Nonetheless, important differences existed in numbers and types of species represented by the two methods. Ninety-three species were detected on point counts only and 35 were captured only. Ten families, including ecologically important ones such as Psittacidae and Cotingidae, were not represented by captures. Elevational migrants and threatened species occurred throughout the gradient, illustrating the need to protect forest at all elevations. A comparable study from the Cordillera de Tilarán (Young et al. 1998) demonstrated similar patterns of species change along an elevational gradient. Comparisons with that study illustrated that point counts are a valuable complement to mist-net studies. Both studies indicated the diverse nature of the avifauna along elevational gradients in Costa Rica.

Species diversity and community composition of birds change rapidly along elevational gradients in Costa Rica. Such changes are of interest ecologically and illustrate the value of protecting continuous gradients of forest. We used mist nets and point counts to sample birds along an elevational gradient on the northeastern Caribbean slope of the Cordillera Central in Costa Rica. Sites included mature tropical wet forest (50 m); tropical wet, cool transition forest (500 m); tropical premontane rain forest (1,000 m); and tropical lower montane rain forest (1,500 and 2,000 m). We recorded 261 species from 40 families, including 168 species captured in mist nets (7,312 captures) and 226 detected during point counts (17,071 observations). The sample included 40 threatened species, 56 elevational migrants, and 22 latitudinal migrants. Species richness (based on rarefaction analyses) changed little from 50 to 1,000 m but was lower at 1,500 and 2,000 m. Mist nets and point counts often provided similar views of community structure among sites based on relative importance of difference categories of species (e.g. migrant status, trophic status). Nonetheless, important differences existed in numbers and types of species represented by the two methods. Ninety-three species were detected on point counts only and 35 were captured only. Ten families, including ecologically important ones such as Psittacidae and Cotingidae, were not represented by captures. Elevational migrants and threatened species occurred throughout the gradient, illustrating the need to protect forest at all elevations. A comparable study from the Cordillera de Tilarán (Young et al. 1998) demonstrated similar patterns of species change along an elevational gradient. Comparisons with that study illustrated that point counts are a valuable complement to mist-net studies. Both studies indicated the diverse nature of the avifauna along elevational gradients in Costa Rica.

Knowledge of bird species diversity along elevational gradients is key for understanding the distributional limits of species and, ultimately, for promoting measures that conserve biodiversity. In the present study, we evaluated changes in bird species richness, diversity, and endemism along an elevational gradient in the Sierra Madre del Sur in southern Mexico -a globally recognized biodiversity hotspot. Monthly bird surveys were carried out at localities with elevations of 1600, 1800, 2000, and 2200 m over the course of one year (2014-2015) covering an area of 2000 km2 (10 circular plots with a radius of 25 m per elevation site). Diversity was calculated in terms of effective number of species or Hill numbers, while the composition of bird species along the elevational gradient was analyzed by non-metric multidimensional scaling, and endemic bird species turnover was assessed with faunal congruence curves. Overall, a total of 118 bird species belonging to 35 families were recorded along the elevational gradient. Although we found that bird richness and diversity increased with increasing elevation, we also observed significant turnover in bird composition and endemic species, which were likely linked to forest types and conditions, as well as proximity of sites to urban centers. Assessing biodiversity patterns across elevational gradients in a well-recognized biodiversity reservoir advances both understanding of ecological patterns and aids conservation efforts and management of biological resources.

Anthropogenic climate change is altering biological communities, ecosystems and their associated services. Understanding contemporary distribution and diversity patterns and accurately predicting biological responses to climate change is therefore necessary to help assess the nature of future changes and to mitigate associated negative impacts. Predicting responses to climate change is a particular challenge for invertebrates, for which distributions are often poorly known despite representing most of the Earth's species, and being especially sensitive to a changing climate. There is particular concern about the impact of climate change on the biota of tropical mountains, because tropical species often have particularly narrow geographical and thermal ranges and therefore display high levels of short-range endemism. This thesis examines changes in diversity and distribution patterns of the rainforest ants in the Australian Wet Tropics (AWT) under future climate change. The thesis addresses the question: How will diversity and distribution patterns of rainforest ant communities in the Australian Wet Tropics be affected by future climate change? It has three specific aims. The first is to document spatial variation in rainforest ant diversity and composition in the AWT, and to identify the role of climate as a driver of this variation. Ants were comprehensively sampled in leaf litter, on the litter surface and on tree trunks at 26 sites across elevational gradients spanning from 100 – 1,300 m within six montane subregions that spanned the latitudinal range of the AWT. A total of 79,853 individual ants were collected, belonging to 296 species from 63 genera. Species richness showed a slight peak at mid elevations, but did not vary significantly with latitude. Species composition varied substantially among subregions and changed markedly with elevation, with a striking disjunction at the elevation of the orographic cloud layer. The second aim is to assess the extent to what the distribution of rainforest ant species related to their physiological thermal limits. Maximum thermal limits (CTmax) and body mass of 20 species were examined along one of the elevational gradients. Phylogenic relationship was controlled, which there was no significant signal in the data. Community CTmax did not vary systematically with increasing elevation and there was no correlation between elevation and elevational ranges of species. However, body mass significantly decreased at higher elevations, but there was no significant difference in CTmax of different-sized ants within a species and models indicated that elevation and body mass had limited influences on CTmax. The results of this chapter showed direct contradictions with climatic variability hypothesis, Rapoport's rule or Bergmann's rule, which adds to the uncertainty around this issue for ants. The third aim is to investigate how projected climate change and associated changes in suitable habitat will affect rainforest ant community composition in the AWT. Compositional dissimilarity of the communities was estimated using Generalised Dissimilarity Modelling, and the models were fitted into future projections of climatic changes, incorporating projected changes in the distribution of rainforest habitat. Rainforest ant community composition was forecast to change markedly under projected climate change, primarily because of predicted changes in rainforest habitat, especially on the inland side of the region. Habitat suitability is predicted to reduce due to projected transformation of rainforest to sclerophyll forest, which will likely shift the community composition completely from the sites that the rainforest will remain intact. This is an additional change to the expected turnover in the rainforest community composition due to changing climate only. Noteworthy findings of the thesis are the importance of the orographic cloud layer between 600 m and 800 m elevation as a driver of variation in species composition and likelihood of climate change impact on ant species primarily through changes in rainfall via its effects on vegetation structure and therefore thermal microhabitats, than through direct temperature changes. These findings highlight the sensitivity of the cloud layer zone and vegetation structure in the AWT to a changing climate. Therefore, key future directions for predicting ant community responses to climate change are to incorporate changes in the cloud layer and thermal mircohabitats, via changes in rainforest habitat, into compositional dissimilarity modelling.

The diversity and biogeography of the Antarctic benthos has been shaped by its unique history through glacial cycles, the influence of circumpolar current regimes and seasonal food inputs. There is currently a large international research effort to define levels of species diversity, biogeography, functional traits and their sensitivity to changing environmental conditions. These data are vital in setting ecological baselines to monitor the effects of climate change and manage the impacts of human activities in the Southern Ocean. The findings from genetic level analyses into species diversity, biogeography and the trophic traits of two groups of benthic Antarctic polychaetes, an abundant taxa within macrofaunal communities are presented here. The first group contained free-living polychaetes collected from the Scotia, Amundsen and Weddell Seas, whilst the second group consisted of symbiotic polynoids taken from coral host species in the South Orkney Islands Southern Shelf Marine Protected Area. The application of DNA barcoding to a subset of 15 morphologically identified polychaete species (morphospecies) from the free-living polychaetes, uncovered 10 additional cryptic species (these individuals are morphologically identical but genetically distinct) and 10 previously overlooked morphospecies. These findings suggest that the levels of Antarctic benthic diversity may be largely underestimated. The difficulty in determining true ‘species’ from genetic analysis for which there are no genetic cut offs or rules is discussed, as well as the causes of misidentification of soft bodied species within large sample sets. The distribution of cryptic species are often more restricted that that of their original morphospecies. This is potentially related to geographic or reproductive isolation of populations during the speciation process. In this study, the cryptic species previously considered to be circum-Antarctic remained widespread. This demonstrates the importance of considering dispersal mechanisms, including developmental mode and larval biology and subsequently transport via cicrum-Antarctic currents. The determination of trophic traits using both bulk and compound specific stable isotope analysis, revealed high levels of variability within and between species with the same categorical trophic traits. These data suggest a high degree of omnivory coupled with variation at the base of the food web i.e. in 15N of phytoplankton/phytodetritus. The use of genetic and biochemical analyses to describe the symbiotic relationship between polynoid symbionts and their host corals identified polymorphisms with significantly different trophic signatures. The relevance and significance of the findings are discussed with regard to environmental change in the Southern Ocean and the future of Antarctic marine management and scientific research. Antarctica represents one of the most rapidly changing and vulnerable ecosystems on our planet. Any means to mitigate the effects of climate change or to sustainably manage Antarctic marine resources requires international and multidisciplinary research collaborations. Future research should focus on understanding the interacting and changing relationships between the biological, chemical, physical and geological environments.

The local extinction of habitat patches and dispersal between the patches are important processes structuring animal populations in heterogeneous environments. Understanding these two processes is crucial for the conservation of wildlife populations in landscapes impacted by human land-use. Approximately 50% of the subtropical rainforest in South East Queensland, Australia has been lost to deforestation over the last 100 years. While large areas of rainforest are reserved, little is known about the distribution and population status of rainforest birds within smaller remnants in the region. The overall research problem for this thesis was to understand how deforestation and fragmentation of subtropical rainforest affects the occurrence of rainforest birds and the effective dispersal of a rainforest-restricted species, the logrunner (Orthonyx temminckii). Understanding why some bird species are lost from habitat patches while others remain will lead to improved conservation of extinction prone species in fragmented landscapes. Although the mechanisms underlying local extinctions are well established in temperate systems, the relative importance of local and regional processes on species occurrence in subtropical and tropical rainforests is poorly understood. Chapter 2 investigated the relative effects of life history and scale of habitat modification on avian site occupancy using observational data collected at 46 rainforest sites in South East Queensland. A probabilistic model for the joint site occupancy of 29 bird species was used to evaluate hypotheses for the effects of avian life history traits on the occurrence of multiple species. The single-species occurrence models incorporated habitat effects on detection, which may be especially important in rainforests because dense vegetation and idiosyncratic occurrence of species can interfere with sampling. Occupancy rates for each species were modelled to determine the relative influence of process operating at the stand, landscape and patch scales. The life history analysis indicated taxonomic Family, body mass, migratory strategy and feeding strata had large effects on avian site occupancy, whereas abundance traits such as mean density and extent of occurrence showed little predictive ability. After accounting for correlated extinction risk attributed to life history, the degradation of stand structure at the local scale was more important for species richness than habitat modification at landscape or patch scales. While individual species showed various responses to the different scales of habitat modification, the distribution of many species was limited by vegetation structure at the landscape scale. Maintaining stand basal area and restoring degraded rainforests at the local scale will increase the probability of occupancy for members of the rainforest bird community. However, revegetation and retention of forest cover at the landscape scale may be necessary for the successful colonisation of many species. Chapter 3 introduced a predictive hypothesis-driven approach for quantifying the relative contribution of historic and contemporary processes to genetic connectivity. Current analytic frameworks in population genetics have difficulty evaluating meaningful hypotheses about spatial processes in dynamic landscapes. Confronting genetic data with models of historic and contemporary landscapes allowed the identification of dispersal processes operating in naturally heterogeneous and human-altered systems. Two measures of indirect gene flow were estimated from microsatellite polymorphism among 11 logrunner populations. Of particular interest was how much information in the genetic data was attributable to processes occurring in a reconstructed historic landscape and a contemporary human-modified landscape. A linear mixed model was used to estimate appropriate sampling variance from non-independent data and information-theoretic model selection provided strength of evidence for alternate hypotheses. The historic and contemporary landscapes explained an equal proportion of variation in genetic differentiation and there was considerable evidence for a temporal shift in dispersal pattern. Migration rates estimated from genealogical information were primarily influenced by contemporary landscape change. Landscape heterogeneity appeared to facilitate gene flow prior to European settlement, but contemporary deforestation is rapidly becoming the most important barrier to logrunner dispersal. Understanding asymmetric dispersal is becoming an important consideration for the conservation metapopulations. Populations acting as net exporters of dispersing animals may be able to rescue local populations from extinction and allow metapopulations to persist in degraded landscapes impacted by habitat loss. In Chapter 4, I estimated bidirectional migration rates from genetic data to infer dispersal among 11 logrunner populations. The first question posed was, does logrunner dispersal correspond to the source-sink or balanced model of dispersal? The second question involved determining the strength of evidence for two hypotheses about how landscape structure has affected asymmetric dispersal. Hypothesis one proposed that asymmetric dispersal was primarily influenced by naturally occurring habitat heterogeneity. Hypothesis two asserted that asymmetric dispersal was predominantly influenced by anthropogenic landscape change. The data were confronted with the alternate hypotheses using linear mixed models and landscape covariates extracted from digital maps. The results showed the direction of asymmetric dispersal was consistent with source-sink population structure. I also discovered that the asymmetry in dispersal was influenced more by anthropogenic landscape change than by naturally occurring habitat heterogeneity. Intact landscapes were net exporters of dispersing logrunners while landscapes heavily impacted by rainforest clearing were net importers of individuals. Elevated immigration rates into landscapes impacted by rainforest clearing appeared to arrest population declines in accordance with the rescue effect. The primary conclusion emerging from the study of patch occupancy and dispersal was that logrunner populations in South East Queensland conformed to a mainland-island metapopulation. Asymmetric dispersal from the largest expanse of upland rainforest appeared to prevent fragmented rainforests in close proximity from going locally extinct. While the distribution of logrunners was limited by the spatial configuration of rainforest patches, other rainforest birds exhibited variable responses to scale of habitat modification. The most consistent pattern was several species dropping-out of the community in degraded stands affected by selective timber harvest. Deforestation at the landscape scale also played a role in the extremely low patch occupancy rates of Albert’s lyrebirds (Menura alberti) and green catbirds (Ailuroedus crassirostris).

The extraordinary diversity of species-environment relationships that occur across space and time can engender a deep curiosity of their mechanistic underpinnings. Moreover, the rapid rate of ecosystem change associated with anthropogenic and climatic pressures makes information regarding species' landscape and resource use ever more important. Without this information, we will be unable to effectively protect landscapes and their constituent species. The coastal ecosystem mosaic of northeast Australia, which is comprised of a high diversity of habitat types, provides a suitable region for investigating how species respond to heterogeneity in habitat and resource availability. The present thesis examined ecosystem functioning in heterogeneous coastal landscapes of northeast Australia for forest avifauna. An array of analytical approaches were employed to establish a comprehensive understanding: 1) spatial assessment to determine relationships between regional landscape connectivity and coastal forest bird assemblages, 2) isotopic assessment to evaluate the local foraging ecology of mangrove bird assemblages, and 3) nutrient assessment of cross-ecosystem connectivity provided by a migratory coastal forest bird species (i.e. the Pied Imperial-Pigeon (Ducula bicolor)). Within the coastal ecosystem mosaic, mangrove forests sit at the land-sea interface. Therefore, to effectively 'set the scene' I review how mangrove birds require and facilitate connectivity through their use of the broader coastal landscape. Next, to specifically assess regional landscape patterns and processes influencing northeast Australia's coastal forest avifauna, I surveyed the composition of bird assemblages in four of the major coastal forest types occurring throughout the region (i.e. Eucalypt, Melaleuca, mangrove, and rainforest). Following this, spatial patterns of habitat configuration within the coastal landscape (i.e. structural connectivity) were quantified to understand broad relationships between coastal forest bird assemblage composition and landscape heterogeneity at multiple spatial scales. Most bird species in coastal northeast Australia occurred in multiple forest types. Spatial assessment suggested that Melaleuca woodlands are a keystone structure that supports use of the entire coastal landscape mosaic by coastal forest generalist species. However, the species composition of mangrove bird assemblages was distinct relative to other coastal forest types. Therefore, to provide more detailed information regarding the response of coastal forest generalists and mangrove specialists to specific forest attributes, functionally connected forest networks were developed to assess the relative importance of forest area, availability, and connectivity to their compositional turnover. This revealed that mangrove specialists and coastal generalists differ in the forest attributes they require (i.e. area vs. availability) to maintain regional beta diversity. Understanding landscape pattern-process relationships that drive bird assemblage composition and turnover can inform the prioritization of regional-scale landscape features for protection. However, species' responses to local-scale spatiotemporal variability in resource availability may also play a role in these relationships. I used isotopic analysis to better understand the foraging ecology of coastal forest birds in a highly dynamic mangrove forest environment. This demonstrated that flexible and opportunistic foraging strategies were prevalent among coastal forest generalist species. However, specialized foraging strategies were employed by some species, primarily for resources that were uniquely available in mangrove forests (i.e. estuarine fish and crabs). Mobile species not only respond to landscape patterns and processes, but can also facilitate connectivity processes through their movement (e.g. nutrient transfer, pollination, genetic linking, etc.). To determine the implications of avian mobility for ecosystem functioning in northeast Australia, I focused on a migratory coastal forest bird species, the Pied Imperial-Pigeon (Ducula bicolor). Nutrient measurements demonstrated that Pied Imperial-Pigeons provide mainland-derived nutrient subsidies to island forests, highlighting their important role as an avian mobile-link species. The integrated analytical approach used in this thesis has provided insight to the complexity of coastal landscapes and their use by forest avifauna. This has broadened our understanding of coastal ecosystem functioning to include a hierarchy of ecosystem components that exist at local and regional scales. The ecosystem properties that emerge from interactions across coastal ecosystem components include: vegetative connectivity, compositional turnover, avian foraging strategy, and nutrient transfer. Results from this thesis can inform the holistic conservation and management strategies that are required to maintain coastal ecosystem functioning in regional northeast Australia.

Sri Lanka’s protected areas are increasingly becoming prime tourism destinations for bothinternational and domestic tourists. Ironically, most nature-based tourism activities areconcentrated on few well-known National Parks and Forest Reserves in the country. As aresult, these sites are continuously subjected to increased visitor pressure. Conservationistsfrequently cite human recreational disturbances of wildlife as one of the key issues inbiodiversity conservation, especially in protected areas open for public visitation. Behaviourof birds has been found to be often influenced by human recreational activities; yet scientificevidences to assess the degree of this threat are limited in literature, especially in the SriLankan context. This study investigated the effects of human recreational disturbances on the distribution of39 species of birds along a highly visited nature trail in Sinhararja World Heritage Forest, SriLanka, from May to November, 2013. The study employed eighteen 25 m fixed-radius pointcounts laid perpendicular to the nature trail (six counts along the nature trail, and six countseach100m and 200 m perpendicular to the trail). Each point count was visited at least 18times during the study period at different times of the day. Point counts recorded 37 breedingresident species of which 17 were endemic, while there were two migrant species. Humanrecreational disturbances were defined in terms of visitor group size (visual disturbance) andtheir relative noise level (noise disturbance). Accordingly, four disturbance levels (no humandisturbance, low human disturbance, medium human disturbance and high humandisturbance) were derived using a two-step clustering procedure. The relationship betweendisturbance levels and abundance of birds was statistically tested Results revealed a significant negative correlation between visitor numbers and abundance ofbirds in point counts on the trail (Spearman's rho = -0.20, p=0.045), and a significantpositive correlation between the same variables in plots 200m away from the trail at 0.05significance level (Spearman's rho = 0.19, p=0.049). This in general, suggests a possibleavoidance of edge habitats by birds at the human presence and flushing into the forest.Regardless of the disturbance type, mean number of birds recorded was highest in plots onthe trail (mean =14.20 ± SD or SE 1.98) followed by plots 200 m away from the trail (mean=10.11± SD or SE 2.00). Null hypothesis of “bird counts at various distances from the trailare independent of disturbance levels” was tested using Chi-square test for each species. Outof 22 species with sufficient data available for analysis, Ashy-headed laughing thrush(Garrulax cinereifrons) found to shift away from the trail as disturbance levels increased (χ2-=6.41, p=0.041). For the most species recorded in the study, non-significance for Chi-squaretest suggests that these species may have become habituated to low-intensity and predictablehuman recreational disturbances.

The vertical stratification of bird species has been intensively studied in both temperate and tropical bird communities. I investigated the vertical stratification of bird species and their use of vegetation structures and light habitats using observation data from 92 rainforest species. Most observations were made from a 40 m high canopy crane situated close to the Surumoni river (65°40′W, 3°10′N) near Esmeralda, Estado Amazonas, southern Venezuela. Further observations were made at several forest sites nearby. Previous analyses had shown that bird species foraged in stratified vertical niches, with wider niches for midstorey birds than for either canopy or understorey birds. In this study, I used across-species as well as phylogenetically-controlled analyses to correlate the vertical position of bird species with variables relating to vegetation structures and the amount of illumination. I found that species which foraged low in the forest were mostly found in small gap and forest shade light habitats, while species that foraged high were mostly found in large gap and woodland shade light habitats. Furthermore it was the lower-foraging species that were more often found in dimmer light conditions inside denser cover. In correspondence with their wider vertical niches, midstorey birds foraged in a wider range of light habitats and illumination than either canopy or understorey birds. While preserving their overall stratification, species actively moved within their preferred stratum, e. g. downwards and into denser vegetation during hours of strong sunlight and around midday when temperatures are highest. Bird activity appeared to be lowest shortly after midday, as I discovered when controlling for the effects of chance encounters with multi-species flocks. These observations are important not only for the determination of foraging niches, but also for the study of crypsis and the conspicuousness of a bird species in relation to its foraging stratum.

Following Bees and Wasps up Mt. Kilimanjaro: From Diversity and Traits to hidden Interactions of Species