Journal Article

Niche packing and expansion account for species richness-productivity relationships in global bird assemblages

Kissling, W. Daniel, Svenning, Jens-Christian, Aarhus University Research Foundation, University of Utah, Barnagaud, Jean-Yves, Şekercioğlu, Çağan, Aarhus University [Aarhus], Centre d’Ecologie Fonctionnelle et Evolutive (CEFE) ; Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE) ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [Occitanie])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Koç University, Pellissier, Vincent, Universiteit van Amsterdam = University of Amsterdam (UvA)

2018

Overview

Aim: Niche theory proposes that increases in species richness along an environmental gradient are associated with a packing of species inside the niche space or an expansion of the niche space. We test whether and under what conditions an increase in bird species richness along a gradient of resource availability is associated with an expansion or packing of the niche as measured based on traits related to resource use. Location: Global. Time period: Current. Major taxa studied: Birds. Methods: We measured birds’ realized niche space as the standardized departure between observed total trait range and its null expectation (functional richness: SES.FRic) in 12,188 cells worldwide. We first correlated both species richness and this measurement along the global net primary productivity (NPP) gradient using linear regressions. Second, we investigated the nonstationarity of the species richness–NPP relationship with Lee’s bivariate correlation, a measure of the spatial association of two variables. We then assessed the number of cells exhibiting a significant positive species richness–NPP association and a significant negative or positive SES.FRic. Third, we assessed whether species of species-rich assemblages occur within or outside the niche space of species-poor assemblages. Results: At a global scale, we found that species richness and SES.FRic increased with NPP. We also showed that cells with a significant positive association between species richness and NPP exhibited niche packing (1,699 assemblages out of 12,188) more than niche expansion (five assemblages). Niche packing was associated with complex biomes such as tropical rain forests. Finally, by showing that species in species-rich assemblages predominantly occur within the niche space of species-poor assemblages, we showed that the increase in SES.FRic with NPP contributed little to the increase in species richness. Main conclusion: Although niche volume increases with species richness along an NPP gradient, we confirmed that niche packing is the pattern most associated with the species richness–NPP relationship at a global scale.

• Publisher: Wiley,CCSD,John Wiley & Sons Ltd,Wiley Subscription Services, Inc
• Subject: Biodiversity and Ecology / Birds / Bivariate analysis / Correlation analysis / ecosystems / Environmental gradient / Environmental Sciences / Expansion / functional richness / Measurement methods / Net Primary Productivity / net primary productivity (NPP) / niche expansion / niche packing / Packing / primary productivity / Productivity / Rainforests / Resource availability / resources / species diversity / Species richness / Tropical forests / tropical rain forests
• ISBN: 0004309167000