Impact of anthropogenic disturbance on the density and activity pattern of deer evaluated with respect to spatial scale-dependency

This study examined the influence of anthropogenic disturbance (agriculture, forestry, hunting and feral domestic dogs) on the population density and daily activity pattern of deer. We quantified the effects of land use (broad-leaved forest, mixed coniferous/broad-leaved forest, natural grassland, subalpine vegetation, forestry area, and agricultural land), along with hunting pressure, and densities of feral domestic dogs and wild macaques on deer. The effects of land use were analyzed at various spatial scales and a model selection procedure (generalized mixed model) was used to examine the effects of factors on density and daily activity pattern of deer at each spatial scale. The combinations of influential factors differed between density and daily activity pattern and changed with spatial scale. The spatial scale with the smallest Akaike's Information Criterion value was defined as the effective spatial scale for each of density and daily activity pattern. Deer density was affected positively by the percentage of area covered by broad-leaved forest, natural grassland and macaque density, and negatively by percentage of area covered by agricultural land and mixed forest at the effective spatial scales. For the daily activity pattern of deer, agricultural land, forestry area, natural grassland, subalpine vegetation and dog density reduced diurnal and increased nocturnal activity. Crepuscular activity increased with hunting pressure and subalpine vegetation, and decreased with agricultural land. Thus, daily activity pattern was sensitive to more types of anthropogenic disturbance than density. Detecting the appropriate spatial scales at which significant anthropogenic disturbance should be managed is essential for effective wildlife conservation

Effective spatial scales for evaluating environmental determinants of population density in Yakushima macaques

Population densities of wildlife species tend to be correlated with resource productivity of habitats. However, wildlife density has been greatly modified by increasing human influences. For effective conservation, we must first identify the significant factors that affect wildlife density, and then determine the extent of the areas in which the factors should be managed. Here, we propose a protocol that accomplishes these two tasks. The main threats to wildlife are thought to be habitat alteration and hunting, with increases in alien carnivores being a concern that has arisen recently. Here, we examined the effect of these anthropogenic disturbances, as well as natural factors, on the local density of Yakushima macaques (Macaca fuscata yakui). We surveyed macaque densities at 30 sites across their habitat using data from 403 automatic cameras. We quantified the effect of natural vegetation (broad-leaved forest, mixed coniferous/broad-leaved forest, etc.), altered vegetation (forestry area and agricultural land), hunting pressure, and density of feral domestic dogs (Canis familiaris). The effect of each vegetation type was analyzed at numerous spatial scales (between 150 and 3,600-m radii from the camera locations) to determine the best scale for explaining macaque density (effective spatial scale). A model-selection procedure (generalized linear mixed model) was used to detect significant factors affecting macaque density. We detected that the most effective spatial scale was 400 m in radius, a scale that corresponded to group range size of the macaques. At this scale, the amount of broad-leaved forest was selected as a positive factor, whereas mixed forest and forestry area were selected as negative factors for macaque density. This study demonstrated the importance of the simultaneous evaluation of all possible factors of wildlife population density at the appropriate spatial scale