A Mechanistic Approach to Evaluation of Umbrella Species as Conservation Surrogates

Abstract

Although species with large area requirements are sometimes used as umbrella species, their general utility as conservation tools is uncertain. We surveyed the species diversity of birds, butterflies, carabids, and forest-floor plants in forest sites across an area (1,600 km2) in which we delineated large breeding home ranges of Northern Goshawk (Accipiter gentilis). We tested whether protection of the home ranges could serve as an effective umbrella to protect sympatric species of the four taxa. We also used an empirical habitat model of occupancy of home range to examine mechanisms by which the Northern Goshawk acts as an umbrella species. Among species richness, abundance, and species composition of the four taxa, only abundance and species composition of birds differed between sites located inside and outside home ranges, which was due to greater abundance of bird species that were prey of Northern Goshawks inside the home ranges. Thus, although home range indicated areas with high abundance of certain bird prey species, it was not effective as an indicator of the species diversity of all four taxa. We also did not find any difference in species richness, abundance, and species composition between sites predicted as occupied and unoccupied using the habitat model. In contrast, when we selected sites on the basis of each habitat variable in the model, habitat variables that selected sites either in agricultural or forested landscapes encompassed sites with high species richness or particular species composition. This result suggests that the low performance of the Northern Goshawk as an umbrella species is due to this species' preference for habitat in both agricultural and forested landscapes. Species that can adjust to changes in habitat conditions may not act as effective umbrella species despite having large home ranges.

Beyond species richness: an empirical test of top predators as surrogates for functional diversity and endemism

“…In contrast, the relatively high occurrence for generalist owls across all sites makes them less reliable surrogates. This result for the generalist owl is similar with patterns suggested by Ozaki et al (2006) for Accipiter gentilis, who found that this raptor was not an efficient biodiversity surrogate because it often used anthropogenically degraded habitat that were poor in taxonomic diversity. The latter study, however, did not account for the detectability of both the surrogate candidate and target biodiversity, and it did not test for other dimensions of target biodiversity such as endemism or functional diversity.…”

“…Therefore, stand-level structural complexity may be the driver of a positive association between the surrogate candidate and target biodiversity (Drever et al 2008, Lindenmayer et al 2014a). Furthermore, it can expected that not all members of the top predator guild will be reliable surrogates because those that are habitatgeneralists may be able to adapt to degraded habitats (Ozaki et al 2006, Rodríguez-Estrella et al 2008. Studies identifying the potentially contrasting role of specialist and generalist predators as surrogates for functional diversity and endemism will contribute significantly to applied ecology (Martin et al 2015).…”

Rediscovering the ‘umbrella species’ candidateCucujus cinnaberinus(Scopoli, 1763) in Southern Italy (Coleoptera Cucujidae), and notes on bionomy

“…Roberge and Angelstam (2004) proposed that the idea of umbrella species could be used to assess minimum size but also to help in selecting the locations of potential reserves and to determine the composition, structure and processes of ecosystems. Other authors think in a simpler way that umbrella species are large and often wide-ranging animals whose requirements encompass those of many other species (Groom et al 2006) and whose protection, even if they are invertebrates, offers protection to other species sharing the same habitat (Ozaki et al 2006).…”

Arthropods as surrogates of diversity at different spatial scales

“…Several species assemblages have been selected as surrogates based on characteristics that include, among others, their functional role, distribution, threat status or charismatic value (e.g., Bonn et al, 2002Bonn et al, , 2004Ozaki et al, 2006). Still, taxonomic groups are the most commonly applied surrogates.…”