Chloe F. Sato

The Effects of Winter Recreation on Alpine and Subalpine Fauna: A Systematic Review and Meta-Analysis

The ski industry is often perceived as having a negative impact on sensitive alpine and subalpine communities. However, empirical evidence of such impacts is lacking. We reviewed the available literature from the last 35 years to quantify the reported effects of winter recreation on faunal communities. Overall, using one-sample binomial tests (‘sign tests’) we found that the effects of all types of winter recreation-related disturbances (i.e. ski runs, resort infrastructure and winter tourism) were more likely to be negative or have no effect, than be positive for wildlife. More specifically, in Europe, where the majority of the available research was conducted, the impacts of winter recreation were most often negative for fauna. In terms of specific taxa, birds and to a lesser extent mammals and arthropods, responded negatively to disturbance. Results from our meta-analysis confirmed the results from our binomial tests. Richness, abundance and diversity of fauna were lower in areas affected by winter recreation when compared with undisturbed areas. For most regions and taxa, however, empirical evidence remains too limited to identify clear impacts of winter recreation. We therefore conclude that the majority of ski resorts are operating in the absence of knowledge needed to inform effective strategies for biodiversity conservation and ecologically-sound management. Thus, there is an urgent need for more empirical research to be conducted throughout this increasingly threatened ecological community, especially given the indication from the available literature that fauna often respond negatively to winter recreation.

An experiment to test key hypotheses of the drivers of reptile distribution in subalpine ski resorts

Summary Alpine and subalpine ecosystems support many endemic species. These ecosystems are increasingly under threat from human-induced disturbances such as habitat loss and fragmentation as a consequence of ski resort development and expansion. However, limited peer-reviewed research has investigated the impacts of ski-related disturbances on wildlife, particularly on reptiles. To address this knowledge gap, we conducted reptile surveys to determine the patterns of reptile distribution and abundance in Australian ski resorts. Then, using a factorial experimental design, we investigated 1) the influence of temperature and predation in driving observed distributions and 2) how a common ski resort management practice – mowing of modified ski slopes – affected thermal regimes and rates of predation of reptiles on ski runs. We found that the removal of vegetation structural complexity through mowing resulted in significantly higher rates of predation on plasticine models, as well as significantly altered thermal regimes. Crucially, mown ski runs had higher maximum ground temperatures that frequently exceeded the recorded critical maximum body temperatures of the target species of lizards. Thus, mowing has the potential to render these areas unsuitable for thermoregulatory purposes for a large proportion of the potential activity period of reptiles. Together, modifications of the thermal environment and elevated rates of predation appear to explain the avoidance of ski runs by reptiles. To facilitate the persistence of reptiles in disturbed subalpine environments, management plans must focus on implementing strategies that reduce the impact of human activities that alter temperature regimes and predation rates on lizards. Synthesis and Applications. We suggest that the retention of structural complexity on ski runs (e.g. through the cessation of mowing during peak reptile activity periods) and/or revegetation with native plant communities will concurrently provide refuge from predators and buffer against extreme temperatures, making ski runs more hospitable to reptiles. Based on our findings, we emphasize that effective management strategies targeting subalpine biodiversity conservation require an understanding of the drivers that determine species distributions in these landscapes.

Integrating theory into disturbance interaction experiments to better inform ecosystem management

Managing multiple, interacting disturbances is a key challenge to biodiversity conservation, and one that will only increase as global change drivers continue to alter disturbance regimes. Theoretical studies have highlighted the importance of a mechanistic understanding of stressor interactions for improving the prediction and management of interactive effects. However, many conservation studies are not designed or interpreted in the context of theory and instead focus on case-specific management questions. This is a problem as it means that few studies test the relationships highlighted in theoretical models as being important for ecological management. We explore the extent of this problem among studies of interacting disturbances by reviewing recent experimental studies of the interaction between fire and grazing in terrestrial ecosystems. Interactions between fire and grazing can occur via a number of pathways; one disturbance can modify the others likelihood, intensity or spatial distribution, or one disturbance can alter the others impacts on individual organisms. The strength of such interactions will vary depending on disturbance attributes (e.g. size or intensity), and this variation is likely to be nonlinear. We show that few experiments testing fire-grazing interactions are able to identify the mechanistic pathway driving an observed interaction, and most are unable to detect nonlinear effects. We demonstrate how these limitations compromise the ability of experimental studies to effectively inform ecological management. We propose a series of adjustments to the design of disturbance interaction experiments that would enable tests of key theoretical pathways and provide the deeper ecological understanding necessary for effective management. Such considerations are relevant to studies of a broad range of ecological interactions and are critical to informing the management of disturbance regimes in the context of accelerating global change.

Effects of environmental variation and livestock grazing on ant community structure in temperate eucalypt woodlands

Grazing by livestock is a major ecological disturbance, with potential effects on vegetation, soil, and insect fauna. Ants are a diverse and functionally important insect group with many associations with the ground layer, yet recent global syntheses question the importance of grazing effects on ant communities relative to vegetation or soil. We examined the effects of vegetation, soil and grazing on the whole ant community, ant functional groups, and abundant species in temperate eucalypt woodlands, southeastern Australia. We found limited influence of grazing on our vegetation and soil measures, except for a positive association between grazing and exotic perennial grass cover. We also found that exotic grass cover had a negative effect on overall ant abundance and richness, but not functional groups or individual species. Soil C:N ratio had a positive effect on the subdominant Camponotini, and leaf litter cover had a positive effect on the abundance of cryptic species. Partial Mantel tests revealed an effect of both environmental and grazing measures on ant assemblage composition, but constrained ordination showed that leaf litter cover, grass biomass, and native and exotic perennial grass cover had stronger correlations with ant community structure than grazing. Our study shows that both environmental variation and grazing play a role in driving ant community structure, but that key environmental variables such as grass biomass and leaf litter cover are particularly important in temperate eucalypt woodlands. Monitoring of ant communities to measure the benefits of changed grazing regimes for biodiversity should consider contemporary grazing pressure as well as the underlying effects of variation in plants and soils.

Designing for conservation outcomes: The value of remnant habitat for reptiles on ski runs in subalpine landscapes

Subalpine ecosystems are centres of endemism that are important for biodiversity. However, these areas are under threat from the creation, expansion and continued modification of ski runs, activities that have largely negative effects on wildlife. Despite this threat, research on the impacts of ski runs is limited for reptiles—particularly regarding the value of remnant vegetation retained on ski runs. Here we quantify the effects of habitat loss and fragmentation (i.e., patch size, patch isolation and edge effects) on the abundance of a common subalpine lizard and on thermal regimes (a key determinant of lizard distribution) in an Australian ski resort. The number of lizards observed differed significantly with habitat type (ski runs vs. forested areas) and patch isolation, but not patch size. In addition, the edges of patches supported more lizards than any other habitat type. These patterns of lizard distribution can be explained, in part, by the differing thermal regimes in each habitat. Ski runs had significantly higher ground surface temperatures than any other habitat type, precluding their use for a considerable proportion of the activity period of a lizard. In comparison, edges were characterised by lower temperatures than ski runs, but higher temperatures than the core of forested areas, potentially providing a favourable environment for thermoregulation. Based on our results, we conclude that although modified ski runs have a negative effect on lizards, patches of remnant vegetation retained on ski runs are of value for reptiles and their conservation could help mitigate the negative effects of habitat loss caused by ski run creation.

Hidden collapse is driven by fire and logging in a socioecological forest ecosystem

Significance Almost all descriptions of ecosystem collapse are made after it has occurred and not during the process of collapse. We describe the process of collapse in the iconic Australian Mountain Ash ecosystem. We uncovered empirical evidence for hidden collapse, which occurs when an ecosystem superficially appears to be intact but a prolonged period of decline coupled with long lag times for recovery mean that collapse is almost inevitable. This is because key ecosystem components continue to decline for long periods even after drivers of collapse are removed. Hidden collapse suggests a need for actions well before managers perceive they are required. Long-term monitoring targeting different classes of state variables can be used to provide early warnings of impending collapse. Increasing numbers of ecosystems globally are at risk of collapse. However, most descriptions of terrestrial ecosystem collapse are post hoc with few empirically based examples of ecosystems in the process of collapse. This limits learning about collapse and impedes development of effective early-warning indicators. Based on multidecadal and multifaceted monitoring, we present evidence that the Australian mainland Mountain Ash ecosystem is collapsing. Collapse is indicated by marked changes in ecosystem condition, particularly the rapid decline in populations of keystone ecosystem structures. There also has been significant decline in biodiversity strongly associated with these structures and disruptions of key ecosystem processes. In documenting the decline of the Mountain Ash ecosystem, we uncovered evidence of hidden collapse. This is where an ecosystem superficially appears to be relatively intact, but a prolonged period of decline coupled with long lag times for recovery of dominant ecosystem components mean that collapse is almost inevitable. In ecosystems susceptible to hidden collapse, management interventions will be required decades earlier than currently perceived by policy makers. Responding to hidden collapse is further complicated by our finding that different drivers produce different pathways to collapse, but these drivers can interact in ways that exacerbate and perpetuate collapse. Management must focus not only on reducing the number of critical stressors influencing an ecosystem but also on breaking feedbacks between stressors. We demonstrate the importance of multidecadal monitoring programs in measuring state variables that can inform quantitative predictions of collapse as well as help identify management responses that can avert system-wide collapse.

Predation risk for reptiles is highest at remnant edges in agricultural landscapes

Funding was provided by the Central Tablelands Local Land Services, Lake Cowal Foundation, NSW Office of Environment and Heritage Environmental Trust and the Lake Cowal Foundation.

An evaluation of small-mammal use of constructed wildlife crossings in ski resorts

Abstract Context. Infrastructure development in ski-resort areas has led to the modification of slopes and, often, the replacement of native plant species with exotic grasses. Modified ski slopes are effectively linear areas of disturbance that separate natural habitat and provide barriers to the movement of native animal species. To overcome these barriers, boulder-filled and culvert-style wildlife crossings have been constructed across disturbed ski slopes and under roadways to facilitate the movement of small native mammal species among areas of remnant habitat, but generally they differ in size and locality. The use of boulder-filled and under-road culvert crossings of different length has not been evaluated. Aims. We determine whether fauna utilise wildlife crossings in ski resorts and whether variations in crossing length influence the species using the crossings. Methods. We monitored boulder-filled crossings of two size classes (long or short) biannually from March 2009 to April 2013, using hair tubes. We monitored an additional two under-road culvert crossings with remote infrared cameras. Key results. The results indicated that all crossings, regardless of size, are utilised by small mammals. However, we detected threatened species, such as Mastacomys fuscus (broad-toothed rat), more frequently in crossings of greater length. Conclusions. To maintain linkages for small-mammal populations within ski resorts, we recommend the continued use of boulder-filled crossings on ski slopes. These crossings may be particularly important in facilitating the movement of small mammals across wide areas of ski-slope disturbance. Implications. The context and maintenance of crossings is likely to be important for their long-term use by small mammals, as are complementary strategies to restore structural habitat connectivity on ski slopes, such as strategically implemented native vegetation plantings.