See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/327281010 Functional rarity of coral reef fishes at the global scale: Hotspots and challenges for conservation Article in Biological Conservation · August 2018 DOI: 10.1016/j.biocon.2018.08.011 CITATIONS READS 0 8 7 authors, including: Matthias Grenié David Mouillot Centre d'Ecologie Fonctionnelle et Evolutive Université de Montpellier 10 PUBLICATIONS 8 CITATIONS 357 PUBLICATIONS 13,475 CITATIONS SEE PROFILE SEE PROFILE Pierre Denelle Caroline Tucker Centre d'Ecologie Fonctionnelle et Evolutive University of North Carolina at Chapel Hill 14 PUBLICATIONS 30 CITATIONS 42 PUBLICATIONS 455 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: BIEN - The Botanical Information and Ecology Network View project Ecolottery View project All content following this page was uploaded by François Munoz on 29 August 2018. The user has requested enhancement of the downloaded file. Biological Conservation 226 (2018) 288–299 Contents lists available at ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon Functional rarity of coral reef fishes at the global scale: Hotspots and challenges for conservation T ⁎ Matthias Greniéa, , David Mouillotb, Sébastien Villégerb, Pierre Denellea, Caroline M. Tuckerc, François Munozd, Cyrille Viollea a CEFE, Univ. Montpellier, CNRS, EPHE, IRD, Univ. Paul Valéry Montpellier 3, Montpellier, France b MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France c Department of Biology, University of North Carolina at Chapel Hill, Coker Hall, CB #3280 120 South Road, Chapel Hill, NC 27599-3280, United States of America d University Grenoble-Alpes, LECA, 2233 Rue de la Piscine, 38041 Grenoble Cedex 9, France ARTICLE INFO ABSTRACT Keywords: Characterizing functional diversity has become central in ecological research and for biodiversity assessment. Functional distinctiveness Understanding the role of species with rare traits, i.e. functionally rare species, in community assembly, eco- Evolutionary distinctiveness system dynamics and functioning has recently gained momentum. However, functional rarity is still ignored in Coral triangle conservation strategies. Funrar Here, we quantified global functional and evolutionary rarity for 2073 species of coral reef fishes and Biodiversity facet compared the rarity values to IUCN Red List status. Most species were functionally common but geographically rare. However, we found very weak correlation between functional rarity and evolutionary rarity. Functional rarity was highest for species classified as not evaluated or threatened by the IUCN Red List. The location of functional rarity hotspots (Tropical Eastern Pacific) did not match hotspots of species richness and evolutionary distinctiveness (Indo-Australian Archipelago), nor the currently protected areas. We argue that functional rarity should be acknowledged for both species and site prioritization in conservation strategies. 1. Introduction et al., 2002; Pavoine et al., 2005; Violle et al., 2017b). In this context, it appears urgent to bring organismal functions – e.g., using functional Current conservation plans and policy decisions largely rely on the traits as proxies (Díaz and Cabido, 2001; Violle et al., 2007) – into the evaluation of taxonomic diversity, at both local and large scales (Davies global conservation agenda (Cadotte et al., 2011; Naeem et al., 2012; et al., 2017; Hidasi-Neto et al., 2013; Rosenfeld, 2002; Thuiller et al., Pollock et al., 2017). 2015). For example, current protected areas mostly match with biodi- Conservation efforts usually focus on subsets of emblematic or versity hotspots defined by species number for a given area (Brum et al., threatened species and habitats due to limited resources (Arponen, 2017; Davies et al., 2017; Devictor et al., 2010; Pollock et al., 2017). At 2012). With the ongoing extinction crisis (Ceballos et al., 2017), much the species level, one major conservation tool is the Red List of the emphasis has been put on prioritizing the protection of rare species and International Union for Conservation of Nature (IUCN) (Rodrigues their habitat (Cofre and Marquet, 1999). Species' population size, et al., 2006), which still ignores the diversity of biological attributes geographical range and habitat breadth together de fine several forms of (traits and genes) supported by species (Vié et al., 2009). However, rarity reflecting the potential vulnerability of species to demographic assessing the diversity of organismal evolutionary history has become extinctions and habitat alteration (Rabinowitz, 1981). More recently, central to biodiversity monitoring and analysis (Cadotte et al., 2013), as phylogenetic relationships have been included in species rarity assess- well as accounting for organismal traits that are linked to species per- ment (Isaac et al., 2007; Redding et al., 2010). In the same vein, Violle formance and niche axes (Díaz and Cabido, 2001; Stuart-Smith et al., et al. (2017b) have recently proposed a framework to define functional 2013; Violle et al., 2007; Violle and Jiang, 2009), so to species coex- rarity, accounting for both distinctiveness of species trait values and istence and ecosystem dynamics (McGill et al., 2006; Violle et al., 2007) species geographical range size. After considering a pool of species and but also to species functional distinctiveness or uniqueness (Chase, a spatial scale, the functional rarity of a species can be quantified based 2013; Godet et al., 2015; Jain et al., 2014; Mouillot et al., 2013; Murray on both the distinctiveness of its trait values compared to the other ⁎ Corresponding author. E-mail address: [email protected] (M. Grenié). https://doi.org/10.1016/j.biocon.2018.08.011 Received 18 October 2017; Received in revised form 27 July 2018; Accepted 17 August 2018 0006-3207/ © 2018 Elsevier Ltd. All rights reserved. M. Grenié et al. Biological Conservation 226 (2018) 288–299 species of the pool and its geographical range compared to the geo- containing coral reefs for easier comparison between sites, ending with graphic extent of the study. In this framework, a species can be geo- 259 cells of 5° by 5° (corresponding to ~555 km by 555 km at the graphically rare because of its small range size, but at the same time Equator, see Fig. A1 for details on data selection). We selected 2073 common in terms of its traits. Conversely, a species can be geo- species (over 6300 reported coral reef fish species) for which functional graphically common with a large range size, but rare in terms of traits. trait information and the position on a phylogenetic tree were avail- The same framework can also apply to define phylogenetic rarity which able. These species belong to 19 fish families (over 169 occurring on is already included in species rarity assessment (Isaac et al., 2007; coral reefs) that are dominant on coral reefs (Kulbicki et al., 2013). Our Redding et al., 2010). Functional rarity as defined by Violle and col- sub-sampling of species compared to the full range of species did not leagues mirrors the concept of functional redundancy (Ricotta et al., change the relative species richness across cells (see Fig. A2, Spearman's 2016; Yachi and Loreau, 1999). Functional redundancy is the fact that a rho = 0.99, p < 0.001). group of individuals (or species) at a given site share similar functions, thus being redundant. While, functional redundancy focuses at the site- 2.2. Trait data level on shared functions, functional rarity concentrates on unshared functions at the species-level. We considered six categorical functional traits representing the Previous works only examined the amount of phylogenetic rarity in ability of tropical-reef fish species to forage resources and to reproduce biodiversity hotspots covered by protected areas (Mouillot et al., 2016), (Mouillot et al., 2014; Villéger et al., 2017, see Appendix B for detailed as it represents a crucial evolutionary heritage and potential for adap- links between traits and functions). Fish size (total body length) was tation (Forest et al., 2007), but ignored functional rarity. When they did coded using six ordered categories: 0–7 cm, 7.1–15 cm, 15.1–30 cm, include functional rarity, phylogenetic and functional rarity did not 30.1–50 cm, 50.1–80 cm, and > 80 cm of body length. Mobility was necessarily match between species (Violle et al., 2017b; Winter et al., coded using three ordered categories: sedentary (including territorial 2013). For example, carnivores at a global scale have concordant species), mobile within a reef, and mobile between reefs. The period of functional and phylogenetic rarity values (Dalerum, 2013), allowing activity was coded using three ordered categories: diurnal, both diurnal consistent strategies to conserve both dimensions. Yet, other studies and nocturnal, and nocturnal. Schooling was coded using five ordered have reported a decoupling of taxonomic, phylogenetic and functional categories: solitary, pairing, or living in small (3–20 individuals), rarities across space (Gonçalves-Souza et al., 2014; Hidasi-Neto et al., medium (20–50 individuals), or large (> 50 individuals) groups. Ver- ff 2013, 2015). If a decoupling between the di erent dimensions of rarity tical position in the water column was coded using three ordered ca- emerges at a global scale, we need to reassess whether current con- tegories: benthic, bentho-pelagic, and pelagic. We