Contrasting effects of pine plantations on two skinks: results from a large-scale ‘natural experiment’ in Australia

The conversion of agricultural land to forest plantations is a major driver of global land-use change, and considering that large portions of the planet are covered by forest plantations, understanding their impact on biodiversity is a research priority. The aim of our study was to quantify the long-term response of two lizard species to the transformation of the matrix surrounding remnant habitat patches (from agricultural land to pine plantations). We used a large-scale (115 sites), long-term (16 years) fully replicated and controlled landscape scale ‘natural experiment’ (the ‘Nanangroe experiment’, Australia) to compare the response of lizard populations to plantation establishment. The study entailed detailed surveys of reptiles in 50 eucalypt patches surrounded by maturing pine Pinus radiata plantations (treatments) and populations inhabiting 55 eucalypt patches surrounded by grazing land (controls). We found that the eastern three-toed earless skink Hemiergis talbingoensis was advantaged by the establishment of the pine plantations (increasing colonization of eucalypt patches embedded within plantations). In contrast, we found that the southern rainbow skink Carlia tetradactyla was negatively affected by surrounding areas of maturing plantations. Thus, our results show that plantations acted as a barrier for one species and increased connectivity for the other. We suggest that leaving areas of land devoid of pines between remnant eucalypt patches may enhance the connectivity for species that respond negatively to plantation establishment while maintaining the beneficial increase in connectivity for others.A.M. is funded by NERP. Funding bodies of the Nanangroe project are Joint Venture Agroforestry Program, NSW Department of Land and Water Conservation, the Australian Research Council, the Kendall Foundation and the Pratt Foundation

Birds surveyed in the harvested and unharvested areas of a reduced-impact logged forestry concession, located in the lowland subtropical humid forests of the Department of Santa Cruz, Bolivia.

As part of a larger study of reduced-impactlogging effects on bird community composition,we surveyed birds from December to Februaryduring the 2003-2004 wet-season within harvestedand unharvested blocks of the La Chonta forestryconcession, Department of Santa Cruz, Bolivia.The logged forest was harvested using reduced-impactlogging techniques between one and fouryears previously. During point count surveys, weidentified 5062 individual birds, belonging to 155species, and 33 families. We provide a list of birdspecies found within the harvested andunharvested blocks of the concession for thebenefit of other researchers assessing theresponses of Neotropical avifauna to disturbance,and to facilitate increased understanding of thediverse bird assemblages found within thelowland subtropical humid forests of Bolivia

Hollow futures? Tree decline, lag effects and hollow-dependent species

Tree hollows are a critical breeding resource for many organisms globally. Where hollow-bearing trees are in decline, population limitation can be a serious conservation issue. A particular problem in addressing hollow limitation is the long time that ho

Avifauna and urban encroachment in time and space

AIM: Urban expansion significantly alters fringe environments often with unde-sirable impacts on biodiversity. Consequently, there is a need to define clearconservation objectives for areas subject to urban encroachment. Urban fringe development is a highly dynamic process, both spatially and temporally, but few studies are equipped to examine its temporal effects on biota. We aimed to explore the impacts of urban encroachment on avifauna through space and time.LOCATION: The Australian Capital Territory, Australia. METHODS: We used records from an extensive 14-year monitoring programme undertaken in temperate woodland. We fitted hierarchical generalized linear models to assess individual species responses to the distance from monitoring sites to the urban boundary, and the temporal rate of change in this distance through time. We used factorial analysis on mixed data to examine trait group responses to these predictors.RESULTS: Our results indicated that the occurrence of approximately half of the study region’s avifauna is strongly linked to the proximity of their habitat to the urban fringe, but that the impact of urban fringe development on the occurrence of some species changed through time. We identified several species of conservation concern that respond negatively to large annual increases in urban fringe development, irrespective of its proximity to suitable habitat. Species responses to urban proximity were linked to life history traits, with small,migratory, woodland-dependent species that rely on mid- and upper-canopy structures, clearly disadvantaged by urban environments.MAIN CONCLUSIONS: Our findings demonstrate the breadth of species responses to urban encroachment over much larger distances than is typically investigated in urban ecological studies. We identify guilds vulnerable to the impacts of urban fringe development and therefore in need of ecologically sensitive urban design. We argue that future urban expansion towards important fringe habitats will need to be planned strategically through space and time.This research received funding support from Conservation Planning and Research, Environment and Sustainable Devel-opment Directorate ACT Government and the Fenner Schoolof Environment and Society. DBL, PG and KI were sup-ported by the National Environmental Research Program. ADM was supported by an ARC Future Fellowship (FT100100358)

How Accurate Are Population Models? Lessons From Landscape-Scale Tests In A Fragmented System

There is a growing debate about the ability of Population Viability Analysis (PVA) to predict the risk of extinction. Previously, the debate has focused largely on models where spatial variation and species movement are ignored. We present a synthesis of the key results for an array of different species for which detailed tests of the accuracy of PVA models were completed. These models included spatial variation in habitat quality and the movement of individuals across a landscape. The models were good approximations for some species, but poor for others. Predictive ability was limited by complex processes typically overlooked in spatial population models, these being interactions between landscape structure and life history attributes. Accuracy of models could not be determined a priori, although model tests indicated how they might be improved. Importantly, model predictions were poor for some species that are among the best studied vertebrates in Australia. This indicated that although the availability of good life history data is a key part of PVA other factors also influence model accuracy. We were also able to draw broad conclusions about the sorts of populations and life history characteristics where model predictions are likely to be less accurate. Predictions of extinction risk are often essential for real-world population management. Therefore, we believe that although PVA has been shown to be less than perfect, it remains a useful tool particularly in the absence of alternative approaches. Hence, tests of PVA models should be motivated by the cycle of testing and improvement

The Effects of Wildfire on Mortality and Resources for an Arboreal Marsupial: Resilience to Fire Events but Susceptibility to Fire Regime Change

BACKGROUND: Big environmental disturbances have big ecological effects, yet these are not always what we might expect. Understanding the proximate effects of major disturbances, such as severe wildfires, on individuals, populations and habitats will be essential for understanding how predicted future increases in the frequency of such disturbances will affect ecosystems. However, researchers rarely have access to data from immediately before and after such events. Here we report on the effects of a severe and extensive forest wildfire on mortality, reproductive output and availability of key shelter resources for an arboreal marsupial. We also investigated the behavioural response of individuals to changed shelter resource availability in the post-fire environment. METHODOLOGY/PRINCIPAL FINDINGS: We fitted proximity-logging radiotransmitters to mountain brushtail possums (Trichosurus cunninghami) before, during and after the 2009 wildfires in Victoria, Australia. Surprisingly, we detected no mortality associated with the fire, and despite a significant post-fire decrease in the proportion of females carrying pouch young in the burnt area, there was no short-term post-fire population decline. The major consequence of this fire for mountain brushtail possums was the loss of over 80% of hollow-bearing trees. The types of trees preferred as shelter sites (highly decayed dead standing trees) were those most likely to collapse after fire. Individuals adapted to resource decline by being more flexible in resource selection after the fire, but not by increased resource sharing. CONCLUSIONS/SIGNIFICANCE: Despite short-term demographic resilience and behavioural adaptation following this fire, the major loss of decayed hollow trees suggests the increased frequency of stand-replacing wildfires predicted under climate change will pose major challenges for shelter resource availability for hollow-dependent fauna. Hollow-bearing trees are typically biological legacies of previous forest generations in post-fire regrowth forests but will cease to be recruited to future regrowth forests if the interval between severe fires becomes too rapid for hollow formation

Can individual and social patterns of resource use buffer animal populations against resource decline?

Species in many ecosystems are facing declines of key resources. If we are to understand and predict the effects of resource loss on natural populations, we need to understand whether and how the way animals use resources changes under resource decline. We investigated how the abundance of arboreal marsupials varies in response to a critical resource, hollow-bearing trees. Principally, we asked what mechanisms mediate the relationship between resources and abundance? Do animals use a greater or smaller proportion of the remaining resource, and is there a change in cooperative resource use (den sharing), as the availability of hollow trees declines? Analyses of data from 160 sites surveyed from 1997 to 2007 showed that hollow tree availability was positively associated with abundance of the mountain brushtail possum, the agile antechinus and the greater glider. The abundance of Leadbeater's possum was primarily influenced by forest age. Notably, the relationship between abundance and hollow tree availability was significantly less than 1:1 for all species. This was due primarily to a significant increase by all species in the proportional use of hollow-bearing trees where the abundance of this resource was low. The resource-sharing response was weaker and inconsistent among species. Two species, the mountain brushtail possum and the agile antechinus, showed significant but contrasting relationships between the number of animals per occupied tree and hollow tree abundance. The discrepancies between the species can be explained partly by differences in several aspects of the species' biology, including body size, types of hollows used and social behaviour as it relates to hollow use. Our results show that individual and social aspects of resource use are not always static in response to resource availability and support the need to account for dynamic resource use patterns in predictive models of animal distribution and abundance.This research was supported by grants from the Hermon Slade Foundation (HSF 08-4; www.hermonslade.org.au) and the Australian Research Council (www.arc.gov.au), including an APD fellowship to Sam Banks (ARC DP 0984876)

Habitat Selection and Post-Release Movement of Reintroduced Brown Treecreeper Individuals in Restored Temperate Woodland

It is essential to choose suitable habitat when reintroducing a species into its former range. Habitat quality may influence an individual's dispersal decisions and also ultimately where they choose to settle. We examined whether variation in habitat quality (quantified by the level of ground vegetation cover and the installation of nest boxes) influenced the movement, habitat choice and survival of a reintroduced bird species. We experimentally reintroduced seven social groups (43 individuals) of the brown treecreeper (Climacteris picumnus) into two nature reserves in south-eastern Australia. We radio-tracked 18 brown treecreepers from release in November 2009 until February 2010. We observed extensive movements by individuals irrespective of the release environment or an individual's gender. This indicated that individuals were capable of dispersing and actively selecting optimum habitat. This may alleviate pressure on wildlife planners to accurately select the most optimum release sites, so long as the species' requirements are met. There was significant variation in movement between social groups, suggesting that social factors may be a more important influence on movement than habitat characteristics. We found a significant effect of ground vegetation cover on the likelihood of settlement by social groups, with high rates of settlement and survival in dry forests, rather than woodland (where the species typically resides), which has implications for the success of woodland restoration. However, overall the effects of variation in habitat quality were not as strong as we had expected, and resulted in some unpredicted effects such as low survival and settlement in woodland areas with medium levels of ground vegetation cover. The extensive movement by individuals and unforeseen effects of habitat characteristics make it difficult to predict the outcome of reintroductions, the movement behaviour and habitat selection of reintroduced individuals, particularly when based on current knowledge of a species' ecology.The project has been made possible by funding from:Birding NSW (www.birdingnsw.org.au), Birdlife Australia – Stuart Leslie Bird Research Award (www.birdlife.org.au), Canberra Ornithologists Group, Canberra Birds Conservation Fund (www.canberrabirds.org.au),The Conservation and Landscape Ecology Group within the Fenner School of Environment and Society at The Australian National University (http://fennerschool-research.anu.edu.au/​cle/), The Fenner School of Environment and Society at The Australian National University (http://fennerschool.anu.edu.au/), The Foundation for National Parks and Wildlife (www.fnpw.org.au), Gould League of NSW 2010 Centenary Year Cayley Memorial Scholarship (www.gould.edu.au), The Mulligans Flat-Goorooyarroo Woodland Experiment (ARC Linkage Project LP0561817) (http://www.mfgowoodlandexperiment.org.au​/),The Norman Wettenhall Foundation (reference 20108002) (www.nwf.org.au), In-kind contribution was greatly appreciated from CSIRO Ecosystem Sciences (http://www.csiro.au/Organisation-Structu​re/Divisions/Ecosystem-Sciences.aspx) and The Parks and Conservation Service within the Australian Capital Territory Government Department of Territory and Municipal Services (http://www.tams.act.gov.au/play/pcl). One field assistant was employed (Jenny Newport) using funds from Conservation and Landscape Ecology Group and the Mulligans Flat-Goorooyarroo Woodland Experiment to assist in collecting data obtained through radio-tracking reintroduced brown treecreepers

Habitat Selection and Behaviour of a Reintroduced Passerine: Linking Experimental Restoration, Behaviour and Habitat Ecology

Habitat restoration can play an important role in recovering functioning ecosystems and improving biodiversity. Restoration may be particularly important in improving habitat prior to species reintroductions. We reintroduced seven brown treecreeper (Climacteris picumnus) social groups into two nature reserves in the Australian Capital Territory in south-eastern Australia. This study provided a unique opportunity to understand the interactions between restoration ecology, behavioural ecology and habitat ecology. We examined how experimental restoration treatments (addition of coarse woody debris, variations in ground vegetation cover and nest box installation) influenced the behaviour and microhabitat use of radio-tracked individuals to evaluate the success of restoration treatments. The addition of coarse woody debris benefited the brown treecreeper through increasing the probability of foraging on a log or on the ground. This demonstrated the value of using behaviour as a bio-indicator for restoration success. Based on previous research, we predicted that variations in levels of ground vegetation cover would influence behaviour and substrate use, particularly that brown treecreepers would choose sites with sparse ground cover because this allows better access to food and better vigilance for predators. However, there was little effect of this treatment, which was likely influenced by the limited overall use of the ground layer. There was also little effect of nest boxes on behaviour or substrate use. These results somewhat confound our understanding of the species based on research from extant populations. Our results also have a significant impact regarding using existing knowledge on a species to inform how it will respond to reintroduction and habitat restoration. This study also places great emphasis on the value of applying an experimental framework to ecological restoration, particularly when reintroductions produce unexpected outcomes.The project has been made possible by funding from Birding NSW (www.birdingnsw.org.au), Birdlife Australia – Stuart Leslie Bird Research Award (www.birdlife.org.au), Canberra Ornithologists Group, Canberra Birds Conservation Fund (www.canberrabirds.org.au), the Conservation and Landscape Ecology Group within the Fenner School of Environment and Society at The Australian National University (http://fennerschool-research.anu.edu.au/cle/), the Fenner School of Environment and Society at The Australian National University (http://fennerschool.anu.edu.au/), the Foundation for National Parks and Wildlife (www.fnpw.org.au), Gould League of NSW 2010 Centenary Year Cayley Memorial Scholarship (www.gould.edu.au), the Mulligans Flat-Goorooyarroo Woodland Experiment (ARC Linkage Project LP0561817) (http://www.mfgowoodlandexperiment.org.au/), and the Norman Wettenhall Foundation (reference 20108002) (www.nwf.org.au). In-kind contribution was greatly appreciated from CSIRO Ecosystem Sciences (http://www.csiro.au/Organisation-Structure/Divisions/Ecosystem-Sciences.aspx) and The Parks and Conservation Service within the Australian Capital Territory Government Department of Territory and Municipal Services (http://www.tams.act.gov.au/parks-recreation). One field assistant was employed (Jenny Newport) using funds from Conservation and Landscape Ecology Group and the Mulligans Flat-Goorooyarroo Woodland Experiment to assist in collecting data obtained through radio-tracking reintroduced brown treecreepers. Otherwise, individuals that were employed or contracted by the funders (other than the named authors) did not play any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript

Species Traits Predict Assemblage Dynamics at Ephemeral Resource Patches Created by Carrion

Carrion is an ephemeral and spatially patchy resource that supports a diverse subset of species linked to nutrient cycling and the decomposition process. A number of studies have separately documented changes in the diversity of plants, arthropods and vertebrates at individual carcasses, but there are few studies that have examined how functional traits of different groups of organisms underpin their responses to carrion patches. We used a carrion addition experiment to compare changes in composition and functional traits of insect and plant assemblages at carcasses compared with control sites. We found that significant changes in insect assemblage evenness and heterogeneity was associated with species' dispersal traits, and that plant assemblage responses to subsequent soil nitrogen changes was most apparent among graminoids and exotic species. Beetles at carcasses were twice as large as their counterparts at control sites during the first week of carrion decomposition, and also had higher wing loadings. Plants with high specific leaf area responded faster to the carcass addition, and twice as many species recolonised the centre of carcasses in exotic-dominated grassland compared with carcasses in native-dominated grassland. These results provide an example of how traits of opportunist species enable them to exploit patchy and dynamic resources. This increases our understanding of how carcasses can drive biodiversity dynamics, and has implications for the way carrion might be managed in ecosystems, such as appropriate consideration of spatial and temporal continuity in carrion resources to promote heterogeneity in nutrient cycling and species diversity within landscapes.This research was supported by the Mulligans Flat – Goorooyarroo Woodland Experiment (Australian Research Council Linkage Grants LP0561817 and LP110100126). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript