Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota respond to grazing.

Biodiversity conservation in rangeland environments is often addressed by removing livestock, but inconsistent responses by biota mean that the efficacy of this form of management is hotly debated. Reasons for this inconsistency include the usually short duration and small spatial scale of manipulations compared to the area of grazing properties, as well as divergent responses amongst biota. In low‐productivity arid environments, the pulse‐reserve dynamic also complicates the outcome of manipulations. Here, we tested and extended these ideas in a heterogeneous desert environment in central Australia that consists of small patches of open woodland (gidgee) in a grassland (spinifex) matrix. Taking advantage of a controlled property‐scale removal of cattle, and a rain event that stimulated productivity, we first quantified differences in the vegetation and small vertebrates of these two habitats, and then tracked the diversity, composition, and abundance of these biota for 6–19 months post‐rain. We predicted that the two habitats would differ in the structure, composition, and reproductive output of their constituent plant species. We predicted also that the effects of cattle removal would interact with these habitat differences, with the abundance, richness, and diversity of small mammals and reptiles differing across habitats and grazing treatments. As anticipated, plant species composition in woodland was distinct from that in grassland and varied over time. The effects of cattle removal were habitat specific: Plant composition responded to de‐stocking in woodland, but not in grassland; flowers were more abundant, and palatable plant cover also was greater following cessation of grazing pressure. The responses of small mammals but not reptiles showed some accord with our predictions, varying over time but inconsistently with treatment, and perhaps reflected high variability in capture success. We conclude that the timing and length of sampling are important when evaluating the responses of biota to livestock removal, as is the inclusion of all key habitats in the sampling regime.

The activities of livestock in arid environments typically centre on watering points, with grazing impacts often predicted to decrease uniformly, as radial piospheres, with distance from water. In patchy desert environments, however, the spatial distribution of grazing impacts is more difficult to predict. In this study sightings and dung transects are used to identify preferred cattle habitats in the heterogeneous dune system of the Simpson Desert, central Australia. The importance of watering points as foci for cattle activity was confirmed and it was shown that patchily distributed gidgee woodland, which comprises only 16% of the desert environment, is the most heavily used habitat for cattle away from water and provides critical forage and shade resources. By contrast, dune swales and sides, which are dominated by shade- and forage-deficient spinifex grassland and comprise >70% of the available habitat, were less utilised. These results suggest that habitat use by cattle is influenced jointly by water point location and by the dispersion of woodland patches in a resource-poor matrix. The findings were used to build a modified conceptual model of cattle habitat use which was compared with an original piosphere model, and the consequences for wildlife in environments where the model applies are discussed.

1. The challenges to which plants are exposed in urban environments represent, in miniature, the challenges plants face as a result of global environmental change. Hence, urban habitats provide a unique opportunity to assess whether processes of local adaptation are taking place despite the short temporal and geographical scales that characterize the anthropocene . 2. We quantified the ecological diversity of spontaneously occurring urban habitat patches of A. thaliana. Using plant community indicators, we show that these patches differ in their levels of soil nutrient content and disturbance. Accordingly, plants in each patch displayed significantly different flowering time, size, and fitness. 3. Using a deep sampling approach coupled with reduced genome-sequencing, we demonstrate that most individuals can be assigned to a limited set of clonal lineages; the genetic diversity of these lineages represents the diversity observed in western European populations of the species, indicating that established urban populations originate from a broad regional pool of lineages. 4. We assessed the genetic and phenotypic diversity of these lineages in a set of common garden experiments. We report marked genetic differences in life-history traits, including time of primary and secondary dormancy as well as of flowering. These genetic differences in life-history traits are not randomly distributed but sorted out by ecological differences among sites of origin. 5. Synthesis: Our study shows that the genetically diverse phenology of a regional A. thaliana gene pool is not randomly distributed but filtered by urban environmental heterogeneity. This report is the first to show a pattern of local genetic adaptation within urban environments. We conclude that environmental filtering helps maintain functional diversity within species.

ANTHROPOGENIC change to Australian habitats accelerated rapidly during the late 1800s as sheep grazing spread across the continent. In particular, intensive grazing in arid and semi-arid regions is believed to have vastly altered vegetation communities, triggered extensive soil erosion, and reduced shelter available to small mammals, thus increasing their vulnerability to predation (Morton 1990). It is not surprising, then, that since European settlement 32 species (42%) of mammals inhabiting the arid zone of Australia have become extinct (Landsberg et al. 1997), and many others have suffered major range reductions or are currently considered widespread but rare. This faunal collapse was due to multiple factors (Burbidge and McKenzie 1989; Morton 1990), but the most consistent predictor of marsupial decline is geographic overlap with domestic sheep (Fisher et al. 2003). While overgrazing is a serious broadscale problem, the destruction of naturally occurring pockets of highquality habitat probably played a critical role in the extirpation of species that relied on refugia for survival during droughts (Morton 1990).