Community size can affect the signals of ecological drift and niche selection on biodiversity

Author(s)

Siqueira, Tadeu ^[1] ; Saito, Victor S. ^[2] ; Bini, Luis M. ^[3] ; Melo, Adriano S. ^{[3, 4]} ; Petsch, Danielle K. ^{[3, 5]} ; Landeiro, Victor L. ^[6] ; Tolonen, Kimmo T. ^[7] ; Jyrkankallio-Mikkola, Jenny ^{[8, 9]} ; Soininen, Janne ^[8] ; Heino, Jani ^[10]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Biosci, Ave 24 A 1515, Rio Claro 13506900, SP - Brazil

^[2] Univ Fed Sao Carlos UFSCar, Dept Ciencias Ambientais, Rodovia Washington Luis, Km 235, Sao Carlos 13565905 - Brazil

^[3] Univ Fed Goias, ICB, Dept Ecol, Ave Esperanca S-N, Campus Samambaia, Goiania 74690900, Go - Brazil

^[4] Univ Fed Rio Grande do Sul, IB, Dept Ecol, Ave Bento Goncalves 9500, Porto Alegre 91501970, RS - Brazil

^[5] Univ Estadual Maringa, Programa Posgrad Ecol Ambientes Aquat Continentai, Av Colombo 5790, Maringa 87020900, PR - Brazil

^[6] Univ Fed Mato Grosso, IB, Dept Bot & Ecol, Cuiaba 78068165, MT - Brazil

^[7] Univ Jyvaskyla, Dept Biol & Environm Sci, POB 35, FI-40014 Jyvaskyla - Finland

^[8] Univ Helsinki, Dept Geosci & Geog, POB 64, FI-00014 Helsinki - Finland

^[9] WWF Finland, Lintulahdenkatu 10, FIN-00500 Helsinki - Finland

^[10] Freshwater Ctr, Finnish Environm Inst, Paavo Havaksen Tie 3, FI-90570 Oulu - Finland

• Document type: Journal article
• Source: ECOLOGY; v. 101, n. 6 MAY 2020.
• Web of Science Citations: 1

Abstract

Ecological drift can override the effects of deterministic niche selection on small populations and drive the assembly of some ecological communities. We tested this hypothesis with a unique data set sampled identically in 200 streams in two regions (tropical Brazil and boreal Finland) that differ in macroinvertebrate community size by fivefold. Null models allowed us to estimate the magnitude to which beta-diversity deviates from the expectation under a random assembly process while taking differences in richness and relative abundance into account, i.e., beta-deviation. We found that both abundance- and incidence-based beta-diversity was negatively related to community size only in Brazil. Also, beta-diversity of small tropical communities was closer to stochastic expectations compared with beta-diversity of large communities. We suggest that ecological drift may drive variation in some small communities by changing the expected outcome of niche selection, increasing the chances of species with low abundance and narrow distribution to occur in some communities. Habitat destruction, overexploitation, pollution, and reductions in connectivity have been reducing the size of biological communities. These environmental pressures might make smaller communities more vulnerable to novel conditions and render community dynamics more unpredictable. Incorporation of community size into ecological models should provide conceptual and applied insights into a better understanding of the processes driving biodiversity. (AU)

• FAPESP's process: 19/04033-7 - Metacommunity persistence in highly-variable ecosystems
• Grantee: Tadeu de Siqueira Barros
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 13/50424-1 - Scaling biodiversity in tropical and boreal streams: implications for diversity mapping and environmental assessment (ScaleBio)
• Grantee: Tadeu de Siqueira Barros
• Support Opportunities: Regular Research Grants