Cisneros, L. M. | bioRxiv Science

bioRxiv2019

Dimensions of passerine biodiversity along an elevational gradient: a nexus for historical biogeography and contemporary ecology

AimThe incorporation of functional and phylogenetic information is necessary to comprehensively characterize spatial patterns of biodiversity and to evaluate the relative importance of ecological and evolutionary mechanisms in molding such patterns. We evaluated the relative importance of mechanisms that shape passerine biodiversity along an extensive elevational gradient. LocationManu Biosphere Reserve in the Peruvian Andes TaxonSongbirds (order Passeriformes) MethodsWe quantified elevational gradients of species richness, phylogenetic biodiversity, and functional biodiversity for all passerines as well as separately for suboscines and oscines; determined if phylogenetic or functional biodiversity was consistent with random selection or if there was evidence of particular mechanisms dominating community assembly; and compared patterns for each dimension of biodiversity for the two suborders. ResultsFor all passerines and for suboscines, species richness decreased in a saturating fashion, phylogenetic biodiversity declined linearly, and functional biodiversity was stochastic along the elevation gradient. For oscines, species richness and phylogenetic biodiversity decreased linearly, and functional biodiversity decreased in a saturating fashion. Main conclusionsElevational gradients of biodiversity at Manu result from a combination of adaptations associated with radiations that occurred elsewhere (suboscines in Amazonian lowlands, oscines in colder climes of North America) and an in situ radiation in the Andes (tanagers). Our results suggest a combination of temperature-related physiological constraints and a reduction in functional redundancy associated with decreasing resource abundance at higher elevations molded the passerine assemblages along this elevational gradient. Explicit consideration of historical biogeography and conservatism of ancestral niches is necessary to comprehensively understand the mechanisms that mold gradients of biodiversity.

ecology↗

bioRxiv2019

Integrating multiple dimensions of biodiversity to inform global parrot conservation

Because biodiversity is increasingly threatened by habitat destruction and climate change, conservation agencies face challenges associated with an uncertain future. In addition to changes associated with climate and land use, parrots are threatened by hunting and capture for the pet trade, making them the most at-risk order of birds in the world. Parrots provide key ecosystem services, but remain understudied compared to other major bird orders despite their high extinction risk and ecological importance. Species richness is often used to identify high priority areas for conserving biodiversity. By definition, richness considers all species to be equally different. However, ongoing research emphasizes the importance of incorporating ecological functions (functional diversity) or evolutionary relationships (phylogenetic diversity) to more fully understand patterns of biodiversity, suggesting that using functional and phylogenetic information could improve conservation strategies. These distinctions among dimensions of biodiversity are important, because (1) areas of high species richness do not always represent areas of high functional or phylogenetic diversity, and (2) functional or phylogenetic diversity may better predict ecosystem function and evolutionary potential, which are essential for effective long-term conservation policy and management.\n\nOur objective was to create a framework for identifying areas of high species richness, functional diversity, and phylogenetic diversity within the global distribution of parrots We combined species richness, functional diversity, and phylogenetic diversity into an Integrated Biodiversity Index (IBI) to identify global biodiversity hotspots for parrots. We found important spatial mismatches among dimensions, which demonstrate that species richness is not always an effective proxy for other dimensions of parrot biodiversity. The IBI is an integrative and flexible index that can incorporate multiple dimensions of biodiversity, resulting in an intuitive and more direct way of assessing comprehensive goals in conservation planning (i.e., healthy ecosystem functioning and climate change resilience).

ecology↗