No abstract

The effect of hay bales and perches as environmental enrichment material was investigated on the behavior, heterophil/lymphocyte (H/L) ratio, footpad dermatitis (FPD), and productivity of Japanese broilers in a commercial farm. About 21,500 birds were allocated to 4 houses: male versus female×control versus treatment house. We observed maintenance behavior, the utilization of hay bales and perches, and the H/L ratio of birds at 3, 5, and 8 weeks of age. FPD was scored and productivity was calculated at about 60 days after hatching. Compared to birds in the control houses, birds in the treatment houses invested more time in stand-resting and moving behaviors (P＜0.01, for each behavior) and less time feeding, drinking, and sit-resting (P＜0.01, for each behavior). Females used the hay bales and perches more than the males (P＜0.1 and P＜0.01, respectively). The activity and utilization of hay bales and perches decreased with age (P＜0.01, for each behavior, respectively). The H/L ratio of birds in the treatment houses was lower than that in the control houses (P＜0.01). The prevalence of FPD was milder in the treatment houses compared to the control houses for females (P＜0.01), but not for males. In conclusion, hay bales and perches represent effective enrichment materials, allowing broilers to express normal behavior, alleviating stress in the younger and lighter birds of both sexes, and reducing FPD in female birds using the hay bales and perches more than males.

No abstract

An understanding of the relationship between vegetation spatial heterogeneity and disturbance and its application to the management are important for maintaining biodiversity and functions of ecosystems. We examined the effects of disturbance by Siberian marmots on the spatial heterogeneity of vegetation at three spatial scales (fine, intermediate and coarse) in a Mongolian grassland. We established a 50 m × 50 m plot around five marmot mounds and another plot in an area with no mounds. Each plot was subdivided into 625 adjacent 4‐m2 square quadrats and the plants in them were surveyed. Spatial heterogeneity was calculated as the mean dissimilarity in species composition among sample quadrats in each plot. The off‐colony plant community was dominated by graminoids, but a variety of plants, including graminoids, forbs and shrubs, were present in the on‐colony plot. The slightly greater fine‐scale heterogeneity in the on‐colony plot compared to the off‐colony plot reflected the presence of either disturbed or undisturbed patch within a single measurement unit, whereas the lower coarse‐scale heterogeneity in the on‐colony plot reflected the presence of both disturbed and undisturbed patches within a single measurement unit. Our results demonstrate the possibility of using the marmot as a conservation tool in our study site as far as a plant biodiversity is targeted.

With our enhanced understanding of the factors that determine biodiversity and assemblage structure has come increasing acknowledgment that the use of an appropriate disturbance regime to maintain spatial heterogeneity is an effective conservation technique. A herbivore's behavior affects its disturbance regime (size and intensity); this, in turn, may modify the associated spatial heterogeneity of plants and soil properties. We examined whether the pattern of spatial disturbance created by the Siberian marmot (Marmota sibirica) affects the spatial heterogeneity of vegetation and soils at a colony scale on the Mongolian steppe. We expected that the difference in management between two types of area (protection against hunting marmots vs. hunting allowed) would result in different behavioral patterns; therefore, we estimated the patterns of spatial disturbance separately in protected and unprotected areas. We then surveyed plant communities and soil nutrients in these areas to assess their spatial heterogeneity. We found that disturbance of both vegetation and soil was more concentrated near marmot burrows in the unprotected area than in the protected area. In addition, the degrees of spatial heterogeneity of vegetation and soil NO(3)-N were greater in the unprotected area than in the protected area, where disturbance was more widely distributed. These results indicate that the spatial pattern of disturbance by herbivores affects the spatial heterogeneity of vegetation and soil properties through changes in the disturbance regime. Our findings also suggest that the intensity of disturbance is more important than its size in determining community structure in Mongolian grasslands.