Large avian frugivores in the Philippines show linear responses to improvements in forest quality

Large avian frugivores are important in ecosystem function, but are seriously threatened across the tropics. To conserve them we must understand their habitat needs and the effects of improved forest management on individual species and the community as a whole. We recorded the presence/absence of 18 parrot, pigeon and hornbill species along nearly 500 km of transects at 24 sites in Luzon, Philippines, and used logistic GLMMs to identify bird-habitat associations based on topographical, forest structure and floristic data taken at 1227 habitat plots. We then searched for more complex relationships and thresholds in species responses along forest quality/restoration gradients using GAMMs. Frugivore species richness was highest in forest with large-girthed trees, although some small-scale agricultural disturbance was tolerated or even favoured. Importantly, richness was highest in forests on flat ground, areas which are usually the first to be converted to agriculture. Individual species were positively associated with large trees but responses to floristic gradients were more variable. Very few species had complex relationships with forest quality; for the great majority, the probability of occurrence increased linearly along the forest quality/restoration gradient. While the precise benefits in terms of seed dispersal, and costs of management, at different points along the quality/restoration gradient are likely to be themselves complex, avian frugivores benefit proportionately from step improvements right along the gradient. Thus, any actions to improve forest quality on Luzon, from reforesting the most degraded lands to preventing degradation of relatively healthy forests, are likely to benefit frugivores

Habitat suitability modulates the response of wildlife to human recreation

Outdoor recreation activities are growing in popularity, causing increasing pressure on wildlife. There arevarious ways in which wildlife reacts to recreation activities, ranging from behavioural to physiological re-sponses, with regional variation in response-intensity within the same species. We tested whether the effects ofhuman recreation are modulated by overall structural habitat suitability, using a model that included vegetationand topography, at both the regional and local habitat use scale. By undertaking a systematic, plot-based surveyover 13 years in 13 study regions across central Europe, we studied how recreation infrastructure and habitatsuitability interact and affect the variation in regional densities and local habitat use of an endangered modelspecies: the western capercaillie (Tetrao urogallus). Both regional densities and local habitat use varied greatlybetween study years and regions. Capercaillie densities were positively correlated with average habitat suit-ability, but significantly reduced when over 50% of the area was influenced by recreation activities. Habitatsuitability was the main predictor determining local habitat use. Recreation infrastructures were avoided: theeffect being stronger in poor habitat conditions, while slightly mediated by high habitat suitability. Our resultsindicate that effects of recreation activities might be mitigated by improving habitat suitability; however this haslimits because it only affects local scale habitat use but not regional densities. We stress the importance ofrecreation-free areas which must cover extensive (i.e. > 50%) parts of the species range