Where less may be more: how the rare biosphere pulls ecosystems strings

Rare species are increasingly recognized as crucial, yet vulnerable components of Earth’s ecosystems. This is also true for microbial communities, which are typically composed of a high number of relatively rare species. Recent studies have demonstrated that rare species can have an over-proportional role in biogeochemical cycles and may be a hidden driver of microbiome function. In this review, we provide an ecological overview of the rare microbial biosphere, including causes of rarity and the impacts of rare species on ecosystem functioning. We discuss how rare species can have a preponderant role for local biodiversity and species turnover with rarity potentially bound to phylogenetically conserved features. Rare microbes may therefore be overlooked keystone species regulating the functioning of host-associated, terrestrial and aquatic environments. We conclude this review with recommendations to guide scientists interested in investigating this rapidly emerging research area

Conservation prioritization can resolve the flagship species conundrum

Conservation strategies based on charismatic flagship species, such as tigers, lions, and elephants, successfully attract funding from individuals and corporate donors. However, critics of this species-focused approach argue it wastes resources and often does not benefit broader biodiversity. If true, then the best way of raising conservation funds excludes the best way of spending it. Here we show that this conundrum can be resolved, and that the flagship species approach does not impede cost-effective conservation. Through a tailored prioritization approach, we identify places containing flagship species while also maximizing global biodiversity representation (based on 19,616 terrestrial and freshwater species). We then compare these results to scenarios that only maximized biodiversity representation, and demonstrate that our flagship-based approach achieves 79−89% of our objective. This provides strong evidence that prudently selected flagships can both raise funds for conservation and help target where these resources are best spent to conserve biodiversity

Vascular plants as surrogates of butterfly and grasshopper diversity on two Swiss subalpine summer pastures

Summer pastures in the Swiss Alps are currently affected by land-use changes that cause a decrease in biodiversity. Although these habitats make up one-third of the whole Swiss agricultural area, direct payments dedicated to support their management are very low. Current political instruments do not support efforts to conserve the biodiversity in these areas, but a vegetation-based approach such as the one implemented in the permanently utilized agricultural areas is under discussion. However, available studies evaluating the surrogate value of vascular plants for other (particularly animal) taxa have yielded inconsistent results, and very few have been conducted in habitats at high elevations. We investigated the extent to which vascular plants are adequate surrogates for butterfly and grasshopper diversity, examining the congruence of species richness and community similarity in two heterogeneous subalpine pastures in the Swiss Alps. Results at the species richness level (Spearman’s rank correlation) varied widely according to the study site and taxa assessed. In contrast, at the community similarity level (Procrustean randomization tests with Bray–Curtis similarity), congruencies between vascular plant and invertebrate taxa were generally highly significant. We therefore recommend the use of community similarity as a basis for estimating biodiversity patterns. Our results suggest that conservation measures aimed primarily at enhancing the floristic diversity of subalpine grasslands are also likely to benefit butterfly and grasshopper diversity, at least at the local scale