Single-species management has long-term consequences for non-target wildlife
Habitat alterations intended to benefit a single species or suite of species are widespread, yet their effects on non-target wildlife are poorly addressed. Given the broad and increasing impact of anthropogenic activities on biodiversity, advancing our understanding of the costs and co-benefits of single-species management for other species of conservation concern is warranted. We investigated the long-term effects of mechanical forest reduction designed to benefit mule deer (Odocoileus hemionus), an economically important game species, on non-target bird and mammal communities in Colorado, USA. We conducted bird point counts and established wildlife cameras in sites where trees were mechanically removed forty years ago, and in undisturbed reference sites. We compared bird and mammal habitat use among these treatment and control sites using dynamic occupancy modeling, and determined the ecological parameters (e.g. vegetation structure and composition) that had the greatest influence on the probability of use.
Our results suggest that forest reduction catalyzes a long-term change-of-state from dense pinyon-juniper forest to sagebrush scrub, consequently changing the wildlife communities that use these areas. We also found that particular wildlife guilds were influenced by specific vegetative characteristics that could be factored into management decisions. For example, bark-gleaning birds were 53% more likely to use reference sites over historically disturbed sites and mean tree diameter had the greatest positive influence on the probability of their presence. Therefore, using forest-clearing techniques that retain some large standing trees may reduce the long-term impacts of mechanical disturbance on bark gleaning birds. By understanding both the short and long-term consequences of single-species management on non-target species, we can enhance our ability to protect and restore the biodiversity of natural communities.