Landscape and local variables benefit rare species and common ones differently

Our ecological knowledge is mainly based on studies about frequent and abundant species, while the vast majority of species are rare; moreover, rare species play crucial role in the evolutionary adaptation of communities to changing land use. Therefore, spatial scale-dependent studies on rare species from the same community may contribute to understanding rare species’ responses. At the same time, by taking into account the effect of landscape structure as well, results of such studies may ease the implementation of conservation management plans or environmental planning. In our research we aimed to assess and quantify the effects of local and landscape-level environmental variables on abundance, incidence and parasitism rates for rare parasitoids belonging to the same community. For this reason, we examined the parasitoid community exploiting the gall-inducing Diplolepis rosae to learn about rare species’ responses to environmental variables at different scales. We have found that local effects on rare species composition diminished while landscape effects increased compared to effects on common species from the same community. Similarly, specific responses of rare species revealed a higher impact of landscape-scale processes than in the case of common species. Although in the case of rare species it is difficult to recognize the effects of environmental changes across spatial scales due to their rarity, we have concluded that the latter are more sensitive to landscape-level changes than common species. Our study underlines the varying importance of environmental changes across spatial scales in the case of both rare and common species; hence rarity and commonness contribute significantly to drawing reliable conclusions about community and interaction patterns.