No abstract

We assessed the response of a guild of endemic medium and large-bodied carabid species to the local (fine-grained) habitat heterogeneity induced by man. The study was conducted by means of trapping (without killing and preservative agents) and radiotracking methods (to collect data on the spatial ecology of the endangered species Carabus olympiae Sella). Habitat differentiation induced by man (a mosaic of beech forests, alpen rose shrubberies and pastures) affected species richness and abundance of the guild, which were significantly higher in forests and/or shrubberies than in pastures. Most species preferred forests and shrubberies, with the only exception of Carabus concolor Fabricius, which preferred open areas. Species distribution was also affected by stone density and cattle grazing intensity. In particular, petrophilous species peaked on the roadside because of the high stone density there (stones amassed during road construction), while species abundances significantly lowered in overgrazed pastures. The compactness of the paths made by C. olympiae individuals (evaluated through a tortuosity index) was significantly higher in beech forests than in alpen rose shrubberies, indicating movements in the latter habitat type were bound by the spatial distribution of shrubs, which imposes a limit on path tortuosity. Our findings suggest that local ground beetle species diversity strongly depends on small-scale anthropogenic variables (namely habitat type, stone density and grazing intensity), and that habitat modifications (namely from forest to shrubbery) may significantly affect species movement patterns. General and local conservation management suggestions are given in conformity with these results.

The Black Grouse Tetrao tetrix is primarily a lekking species, although in some populations solitary display is also common. We analysed data from a 25 year-long survey of an increasing Black Grouse population in the western Italian Alps in order to test whether the numbers of males adopting different tactics conformed to patterns expected based on the hypothesis that dominant birds occupy the leks and solitary displaying birds are subordinate, and that the tendency for birds to be excluded from leks increases with lek size. Four predictions were made to test this hypothesis: (i) the proportion of solitary males would increase as the overall population increases, (ii) there would be a threshold at which there is little or no increase in the size of the lekking population, but continued increase in the population of solitary displaying birds, (iii) available lek habitat would be occupied prior to an increase in solitary displaying males, and (iv) there would be an increase in the use of less preferred habitat by solitary displaying males as the total population increases. Population trends varied according to display status in that the lekking population reached an apparent threshold while the number of solitary males continued to increase, and there was an expansion of the range of solitary males into higher altitudes in years when the population was larger.However, there was no increase in the proportion of solitary males as the total population increased.Furthermore, there was no suggestion that suitable lek habitat was limiting, as the number of leks and the mean size of those leks continued to increase throughout the study period. Although two predictions were supported, the precise patterns of trends, and results of additional analyses, suggested that solitary display is more likely to be an alternative rather than a subordinate tactic. Several factors may promote this apparent dual display tactic in Black Grouse, but habitat structure in this and other Alpine populations is likely to be a key influence.

Unfortunately, there was an error in reporting the location and geographic coordinates of the study site, Mont Avic Natural Park, under the ''Study site'' subheading, in the ''Methods'' section of the original publication. The correct location and coordinates should read: