Teixidó N et al. (2018), Functional biodiversity loss along natural CO2 ...

ECB-ART-46816

Nat Commun 2018 Dec 11;91:5149. doi: 10.1038/s41467-018-07592-1.

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Functional biodiversity loss along natural CO2 gradients.

Teixidó N , Gambi MC , Parravacini V , Kroeker K , Micheli F , Villéger S , Ballesteros E .

Abstract
The effects of environmental change on biodiversity are still poorly understood. In particular, the consequences of shifts in species composition for marine ecosystem function are largely unknown. Here we assess the loss of functional diversity, i.e. the range of species biological traits, in benthic marine communities exposed to ocean acidification (OA) by using natural CO2 vent systems. We found that functional richness is greatly reduced with acidification, and that functional loss is more pronounced than the corresponding decrease in taxonomic diversity. In acidified conditions, most organisms accounted for a few functional entities (i.e. unique combination of functional traits), resulting in low functional redundancy. These results suggest that functional richness is not buffered by functional redundancy under OA, even in highly diverse assemblages, such as rocky benthic communities.

PubMed ID: 30531929
PMC ID: PMC6288110
Article link: Nat Commun

Article Images: [+] show captions

	Fig. 1. Species and functional diversity changes among pH zones. a Barplots show species richness (Sp), number of functional entities (unique trait combinations, FE) and functional richness (volume filled by each assemblage in the four dimensions of the functional space, Vol. 4D). Values are expressed as a relative percentage of the value for the total pool and are displayed above the bars. b Functional space filled by the functional entities (FEs) present in species assemblages from each pH condition. Axes (PCoA1 and PCoA2) represent the first two dimensions of the 4D functional space. Principal coordinate analysis (PCoA) was computed on functional-trait values. Number of species = 72; number of FEs = 68
	Fig. 2. Overall distribution of FE abundance across the functional space. Each point represents a functional entity (i.e. unique combination of functional attributes) and the size of the circles is proportional to the relative cover of the species belonging to a certain functional entity. Number of species = 72; number of FEs = 68

	Fig. 4. Taxonomic and functional biodiversity loss along the pH gradient. The ambient pH zone is characterized by a mosaic of strategies, from ‘faster’ to ‘slower’ life histories, from encrusting to massive and erect forms, including a variety of sizes, both photosynthetic autotrophy and heterotrophy (including filter feeders and grazers/herbivores), and the presence of calcareous skeletons. The low pH zone is mainly characterized by fleshy morphologies, seasonal population dynamics, fast growth and is mainly composed of non-calcareous organisms, where photosynthetic autotrophy is the major energetic resource. The conditions in low pH zones are used to represent atmospheric carbon dioxide concentration values under future climatic conditions with a decrease in surface pH from −0.14 to −0.4 pH units under IPCC RCP2.6 and RCP8.5 by 2100 relative to 1870. The extreme low pH zone is dominated by encrusting-fleshy forms, ‘fast' growth, non-calcareous organisms and photosynthetic autotrophy as the only energetic resource. The encrusting red form is Hildenbrandia crouaniorum, a non-calcareous, perennial red algae. This extreme low pH zone is used to represent more extreme scenarios based on high CO2 emissions or the more distant future by 2500. See Table 1 for names of selected species supporting ecological functions

References [+] :

Alsterberg, Consumers mediate the effects of experimental ocean acidification and warming on primary producers. 2013, Pubmed