Multiple dimensions of biodiversity drive human interest in tide pool communities

Abstract Activities involving observation of wild organisms (e.g. wildlife watching, tidepooling) can provide recreational and learning opportunities, with biologically diverse animal assemblages expected to be more stimulating to humans. In turn, more diverse communities may enhance human interest and facilitate provisioning of cultural services. However, no experimental tests of this biodiversity-interest hypothesis exist to date. We therefore investigated the effects of different dimensions of animal biodiversity (species richness, phyletic richness and functional diversity) on self-reported interest using tide pools as a model system. We performed two experiments by manipulating: (1) the richness of lower (species) and higher taxonomic levels (phyla) in an image based, online survey, and (2) the richness of the higher taxonomic level (phyla) in live public exhibits. In both experiments, we further quantified functional diversity, which varied freely, and within the online experiment we also included the hue diversity and colourfulness arising from the combination of organisms and the background scenes. Interest was increased by phyletic richness (both studies), animal species richness (online study) and functional diversity (online study). A structural equation model revealed that functional diversity and colourfulness (of the whole scene) also partially mediated the effects of phyletic richness on interest in the online study. In both studies, the presence of three of four phyla additively increased interest, supporting the importance of multiple, diverse phyla rather than a single particularly interesting phylum. These results provide novel experimental evidence that multiple dimensions of biodiversity enhance human interest and suggest that conservation initiatives that maintain or restore biodiversity will help stimulate interest in ecosystems, facilitating educational and recreational benefits

Community Dynamics of Browsing and Grazing Ungulates

The world’s 240 ungulate species belong largely to the same guild, feeding on terrestrial plants, and yet, ungulates typically occur in multi-species assemblages. What allows multiple ungulate species dependent on similar resources to coexist? We focus on the role of variation in ungulate body masses and their feeding adaptations in facilitating coexistence at multiple scales. Our analyses of a global dataset of extant ungulates (incl. proboscideans) show that grazing species tend to have significantly larger body masses, browsers significantly smaller, and mixed feeders tend to have body masses similar to the global median of all species. We report evidence for body mass structuring in grazer and browser assemblages at the biome scale, presumably brought about by the interplay of competitive and facilitative interactions. Our analyses of the Pleistocene species assemblage indicate biased extinction of species across body mass extremes, and point to the role of Pleistocene extinctions in determining the continental ungulate assemblages of today. Our findings also indicate the possibility of mass extinctions not just of larger bodied species but of smaller bodied ungulates as well; this may have gone undetected so far, or is most likely, poorly represented in the fossil record