Summary 1.There is a long-term trend of depopulation of rural areas and pasture abandonment throughout the Alps. This trend peaked after the Second World War and is now omnipresent. Its ecological consequences are evident mostly below the timberline, where grassland gradually turns into shrub and, ultimately, to forest. This study addresses the consequences of land abandonment and the decline of pastoral practices on the diversity and structure of the bird communities of the Italian Alps. 2. The breeding birds of Gran Paradiso Natural Park in north-western Italy were surveyed, and bird diversity, abundance of grassland, ecotone, woodland and shrub species were analysed using regression in relation to a set of explanatory variables including elevation, local habitat variables, landscape variables and grazing intensity. 3. Avian diversity increased in abandoned pastures as higher numbers of shrub species followed tree and shrub encroachment. Conversely, open habitat species that benefited from grazing were mostly confined to pure grasslands and high altitudes. 4. The effects of grazing were more evident in the montane belt. Grazing maintained open habitats by limiting tree and scrub encroachment, thereby favouring grassland bird species. At higher altitudes, however, grazing had little effect on typical open habitat alpine species (choughs Pyrrhocorax spp., water pipit Anthus spinoletta , alpine accentor Prunella collaris , wheatear Oenanthe oenanthe , snow finch Montifringilla nivalis , rock thrush Monticola saxatilis ) and only skylark Alauda arvensis and linnet Carduelis cannabina preferred grazed meadows. 5. Synthesis and applications . This study shows that the abandonment of grazing in the Alps has significant effects on bird species diversity and abundance, especially below the timberline where pastoral decline leads to significant changes in vegetation structure. However, grazing importance differs markedly depending on whether the focus is avian α -diversity or grassland bird abundance. Pastoral abandonment leads to an overall increase in avian diversity, but most species invading abandoned pastures are already common, whereas several grassland bird species that are dependent upon grazed pastures have an unfavourable conservation status. Overall, in terms of bird conservation objectives, large-scale abandonment of long-established pastoral habitats and their complete replacement with scrub, or even forest, is likely to be detrimental.

Mountain regions are globally important areas for biodiversity but are subject to multiple human-induced threats, including climate change, which has been more severe at higher elevations. We reviewed evidence for impacts of climate change on Holarctic mountain bird populations in terms of physiology, phenology, trophic interactions, demography and observed and projected distribution shifts, including effects of other factors that interact with climate change. We developed an objective classification of high-elevation, mountain specialist and generalist species, based on the proportion of their breeding range occurring in mountain regions. Our review found evidence of responses of mountain bird populations to climate (extreme weather events, temperature, rainfall and snow) and environmental (i.e. land use) change, but we know little about either the underlying mechanisms or the synergistic effects of climate and land use. Long-term studies assessing reproductive success or survival of mountain birds in relation to climate change were rare. Few studies have considered shifts in elevational distribution over time and a meta-analysis did not find a consistent direction in elevation change. A meta-analysis carried out on future projections of distribution shifts suggested that birds whose breeding distributions are largely restricted to mountains are likely to be more negatively impacted than other species. Adaptation responses to climate change rely mostly on managing and extending current protected areas for both

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Understanding of the role of body mass in structural-functional relationships is pressing, particularly because species losses often occur non-randomly with respect to body size. Our study examined the effects of dung beetle body mass on dung removal at two levels. First, we used the lab experiment to evaluate the efficiency of eight dung beetle species belonging to two functional groups (tunnelers, dwellers) on dung removal. Second, the same species employed in the lab were used in field mesocosms to examine the effects of the two functional groups on dung removal maintaining realistic differences in the total body mass between tunneler and dweller assemblages. Furthermore, the experimental assemblages contained one and four species within each functional group, so the effect of body mass heterogeneity was examined. We used a statistical approach (offset method) which took into account a priori constraints due to the study design allowing us to analyse the effect of larger species in mesocosm style experiments. Body size played a crucial role in dung removal: large beetles were more efficient than small ones and the percentage of removed dung increased with higher body mass heterogeneity. Tunnelers were more efficient than dwellers over both short and long time periods (one month and one year). Significant effects of dwellers were found only after one year. Moreover, our study showed that not including the body mass as an offset in the model resulted in sometimes different results, as the offset expresses dung removal independently of the body mass. This approach confirmed that body size is likely a pivotal factor controlling dung removal efficiency at multiple levels, from single species to overall dung beetle assemblages. Even though other specific traits should be examined, this study has begun to address the consequences of losing individuals with specific traits that are especially sensitive to perturbations.

Summary 1.Treeless mountainous areas at high altitudes have increased in value as wildlife habitat, but they are affected and increasingly threatened by ski-resort developments, in particular by the construction and enlargement of ski-pistes. To assess the extent of this threat, we compared bird diversity and community composition in circular plots centred on (i) ski-runs of recent construction, (ii) grassland habitats adjacent to ski-runs and (iii) natural grassland habitats far from the ski-runs. 2. Plots located in natural grasslands supported the greatest bird species richness and diversity and the greatest grassland species density, whereas those set in ski-pistes presented the lowest values. Plots located beside ski-runs did not support smaller numbers of bird species and diversity than plots of natural areas, but they supported a significantly lower bird density. This suggests that ski-pistes, besides exerting a negative direct effect on the structure of local bird communities, may also exert an indirect, detrimental effect on bird density in nearby patches. 3. Generalized linear models showed that species richness and diversity, and abundance of grassland species were best modelled by combinations of factors, including habitat type (the three categories defined above) and altitude. The category ski-run, in particular, was negatively correlated with species richness, diversity and abundance, and altitude was negatively associated with richness and diversity. 4. Richness and abundance of arthropods were significantly lower in ski-pistes than in the other plot types. Given that many invertebrates were preyed upon by birds, low food availability on ski-runs may be one of the factors reducing the attractiveness of these patches to birds. Synthesis and applications.Retaining the avifauna around ski-resorts is likely to involve developing new, environmentally friendly ways of constructing pistes, such as only removing rocks and/or levelling the roughest ground surfaces, to preserve as much soil and natural vegetation as possible. Restoration of ski-pistes should promote the recovery and maintenance of local vegetation to enhance invertebrate and bird assemblages. In order to not compromise the safety of the ski-runs, it may be necessary to control encroaching shrubs through pruning and/or cattle grazing.