Black grouse response to dedicated conservation management

摘要

Halting and reversing declines of black grouse populations in Britain represents a major conservation challenge. Programmes of dedicated management aiming to benefit black grouse have been introduced oil several sites and areas across the species' British range. These initiatives generally employ various managements, most aimed at improving habitat conditions, but some at reducing direct sources of mortality. Black grouse populations appear to respond to such conservation initiatives, with increases in numbers following the introduction of management in all six cases examined. However, these increases were not always sustained, and the frequent lack of control sites and baseline data means that there is limited ability to assess the full impact of management, and to distinguish management effects from the effects of coincident environmental variation. Similarly, it is difficult to identify the specific managements critical to producing black grouse response. Evidence exists for benefits of reducing large herbivore densities and of reducing generalist predator abundance, although these may be temporary in the case of herbivore reductions. Variation in annual productivity appeared to be a major determinant of population trends at two sites where productivity estimates were available, suggesting that responses to management may often arise via effects on productivity.