Mature leaf selection of Japanese macaques: effects of availability and chemical content

Mature leaf food selection of Japanese macaques was studied in two different altitudinal zones of Yakushima: in the coniferous (1000–1200 m) and coastal forests (0–200 m). Logistic regression analysis was conducted to reveal the effect of chemical [neutral detergent fibre (NDF), crude protein, crude ash, crude lipid, condensed tannin, hydrolysable tannin and crude protein/NDF ratio] and availability properties (density of trees and total basal area) on the macaques' choice between the major food leaves and the rarely eaten or non-food leaves. In both forests, macaques selected leaves with a high crude ash and crude protein content, or a high crude protein/NDF ratio, as major foods. In the coniferous forest, macaques selected leaves with less condensed tannin, but this tendency was absent in the coastal forest. This was because macaques in the coniferous forest suffer from a greater risk of ingesting large amounts of condensed tannins, as their feeding time on mature leaves is seven times as long as that in the coastal forest. Among the chemical and availability properties, stepwise multiple regression analysis revealed that the number of trees (ha⁻¹) was the only significant factor explaining the variations in feeding time among major food leaves, both in the coniferous and coastal forests. The present results suggest that the effect of travelling cost, which can be reduced by selecting common trees, exceeds the benefits gained by selecting high-quality foods.     

Biological invasions provide a framework for reintroductions: selecting areas in England for pine marten releases

We suggest that reintroductions, like biological invasions, have two phases: establishment when a new population becomes self-sustaining, and spread when a population increases its distribution. Stochastic effects on mortality and sex ratios are most likely to determine whether a population becomes established, while factors influencing birth rates will probably most influence spread. Using this establishment-spread structure, we evaluate the autecological suitability of regions in England for pine marten Martes martes reintroductions. Risks of mortality from predator control, traffic accidents and predation by foxes were used to evaluate suitability for establishment. Mortality risk was higher in all potential release regions in England (selected as having 25% or more woodland cover) than in regions of current pine marten distribution in Scotland; risk of predation was higher in the latter. Indices of prey abundance were used to evaluate suitability for populations to spread. Prey indices in potential release regions were generally higher than in regions of current distribution. A relation between prey, woodland cover, and known pine marten densities suggested that potential release regions are capable of supporting relatively high densities of pine martens, though these might be reduced by higher mortality. We concluded that all potential release regions are suitable for pine marten populations to spread. However, reintroductions should first be to regions with lower risk of mortality, in case higher levels of the latter prevent establishment. The suitability of relict regions of distribution in northern England was low until post-war afforestation, suggesting that habitat suitability constrained recovery of relict populations. These regions remain less suitable for reintroductions.     

Fisher Survival in Eastern Ontario

Abstract: Fishers (Martes pennanti) have recolonized eastern Ontario, Canada, but little is known about the survival of this harvested population. We estimated fisher survival and cause-specific mortality in Leeds and Grenville County, Ontario, from 2003–2005. The overall 2-year survival rate (95% CI) was 0.35 (0.21-0.56, n = 59). We attributed observed mortality rates mainly to natural causes (28.6%) and nuisance trapping (21.4%). Given reported recruitment rates, our estimated fisher mortality has likely led to population declines in the study area, especially during 2003. Thus, we do not recommend an increase in fisher harvest quotas in the study area at this time.     

Laboratory Evaluation of the Pathogenicity of Three Isolates of the Entomopathogenic Fungus Beauveria bassiana (Bals.) Vuillemin on the American Cockroach (Periplaneta americana)

Mycopesticides can be ideal for the biocontrol of cockroaches because the habitat of these insects promotes initial fungal infection and its subsequent spread. The pathogenicity of three isolates of Beauveria bassiana to the American cockroach was tested. The insects were treated in three different ways, by direct contact with spore mass, a spore-wheat flour mixture and a spray of an aqueous spore suspension. A mortality of 100% in the first treatment, 67-100% in the second treatment and 17-75% in the third treatment was observed. These results suggest that B. bassiana spore formulations in food baits can be developed for cockroaches.     

Habitat Selection by American Martens in Coastal California

ABSTRACT We investigated habitat selection using single- and mixed-scale modeling at 2 spatial scales, stand and home range, by the only known population of American martens (Martes americana) remaining in the historical range of the Humboldt subspecies (M. a. humboldtensis) in California, USA. During 2000 and 2001, we sampled a 12 times 14 grid with 2-km spacing, using 2 sooted track plates at each grid point. We detected martens at 26 of the 159 grid points. We used resource selection probability functions and an information-theoretic method to model habitat at detection locations. At the stand scale, martens selected conifer-dominated stands with dense, spatially extensive shrub cover (x̄ = 74% cover, SE = 4) in the oldest developmental stage. At the home-range scale, martens selected the largest available patches (x̄ = 181 ha, SE = 14) of old-growth, old-growth and late-mature, or serpentine habitat. Mixed-scale models revealed that habitat characteristics from both scales best explained marten occurrence compared to one scale alone. Dense, spatially extensive shrub cover is a key habitat element for martens in coastal forests. Dense shrubs provide refuge from predators, cover for prey, and may also deter larger-bodied competitors. Managers can increase the likelihood of marten population persistence and encourage expansion in coastal forests by maintaining and restoring late-mature and old-growth, conifer-dominated forests with dense shrub cover in large, contiguous patches.     

Nutritional ecology provides insights into competitive interactions between closely related Martes species

1. Closely related predator species often share several prey items, making it hard to differentiate the effects on their feeding habits of variation in food availability and of competition. We hypothesised that we could overcome this obstacle by quantifying and comparing nutritional niches.
2. We reviewed dietary studies that assessed the relative bulk of each food item, as either per cent biomass or per cent mean volume, in the diet of two closely related species, pine marten Martes martes and stone marten Martes foina, and calculated the nutrient profiles (intakes of protein, lipids and carbohydrates) of each diet.
3. Both martens’ diets were tightly clustered (mean values: 47% of energy from protein, 39% from lipid, and 14% from carbohydrate). In allopatry, the nutritional niches of the two species did not differ, but in sympatry, the stone marten ate more carbohydrates and less protein than the pine marten. In allopatry, the protein intake of the stone marten remained high (45–52%) in very different habitats, from cultivated lowland to Alpine forests.
4. Our data suggest that stone marten frugivory may, at least partially, be the result of interspecific competition. By analysing dietary data in the framework of nutritional ecology, we could compare the feeding requirements of pine martens and stone martens more effectively than by using classical estimates of trophic niche overlap at the food item level. This approach may help to shed light on the trophic relationships of other competing species.