Community assembly inNothobranchiusannual fishes: Nested patterns, environmental niche and biogeographic history

Abstract

The assembly of local communities from regional species pools is shaped by historical aspects of distribution, environmental conditions, and biotic interactions. We studied local community assembly patterns in African annual killifishes of the genus Nothobranchius (Cyprinodontiformes), investigating data from 168 communities across the entire range of regionally co‐existing species. Nothobranchius are small fishes associated with annually desiccating pools. We detected a nested pattern of local communities in one region (Southern Mozambique, with Nothobranchius furzeri as the core and dominant species), but no nestedness was found in the second region (Central Mozambique, with Nothobranchius orthonotus being the dominant species). A checkerboard pattern of local Nothobranchius community assembly was demonstrated in both regions. Multivariate environmental niche modeling revealed moderate differences in environmental niche occupancy between three monophyletic clades that largely co‐occurred geographically and greater differences between strictly allopatric species within the clades. Most variation among species was observed along an altitudinal gradient; N. furzeri and Nothobranchius kadleci were absent from coastal plains, Nothobranchius pienaari, Nothobranchius rachovii, and Nothobranchius krysanovi were associated with lower altitude and N. orthonotus was intermediate and geographically most widespread species. We discuss implications for ecological and evolutionary research in this taxon.

Hatching date variability in wild populations of four coexisting species of African annual fishes

“…N. kadleci is a member of the N. furzeri species group (F‐clade sensu Bartáková et al, ) that is associated with drier conditions than the other two Mozambican Nothobranchius clades (represented by N. orthonotus and N. pienaari , respectively, in the present study). Most notably, N. kadleci is absent from the more humid coastal area, where N. orthonotus and N. pienaari inhabit numerous pools that receive relatively more precipitation (Reichard et al, ).…”

“…G). Locally co‐occurring Nothobranchius species differ in habitat use (Reichard et al, , ), with a tendency for N. pienaari to inhabit pool margins and N. orthonotus to be associated with deeper water. Such differences in habitat use could potentially translate into differences in the location of egg deposition sites among species.…”

“…The study was conducted in southern and central Mozambique, across the entire range of the Southern clade of Nothobranchius (Dorn et al, , ; Bartáková et al, ). Over this large area, three species complexes coexist in sympatry and often co‐occur locally, while species within each complex are always allopatric (Reichard et al, ). The ranges of all species are structured into geographically well‐defined regional clades (Bartáková et al, , ).…”

Local variation in embryo development rate in annual fish

“…Nothobranchius furzeri and N. kadleci represent a pair of sister species with allopatric distribution (Reichard et al, 2017b) and are ecological vicariants with the same food niche (Polačik et al, 2014b). While distinct in colouration (Reichard, 2010), DNA sequence data render them as paraphyletic evolutionary lineages (Bartáková et al, 2015), distributed across southern and Bartáková et al, 2015. central Mozambique.…”

“…While distinct in colouration (Reichard, 2010), DNA sequence data render them as paraphyletic evolutionary lineages (Bartáková et al, 2015), distributed across southern and Bartáková et al, 2015. central Mozambique. The geographic range of N. furzeri is centred in the more arid southern region (Reichard et al, 2009) while that of N. kadleci is centred in the more humid north (Bartáková et al, 2015;Reichard et al, 2017b). Four N. furzeri and four N. kadleci populations were used in the experiment and treated as a single evolutionary unit ( Fig.…”