Morphological divergence and flow‐induced phenotypic plasticity in a native fish from anthropogenically altered stream habitats

Abstract

Understanding population-level responses to human-induced changes to habitats can elucidate the evolutionary consequences of rapid habitat alteration. Reservoirs constructed on streams expose stream fishes to novel selective pressures in these habitats. Assessing the drivers of trait divergence facilitated by these habitats will help identify evolutionary and ecological consequences of reservoir habitats. We tested for morphological divergence in a stream fish that occupies both stream and reservoir habitats. To assess contributions of genetic-level differences and phenotypic plasticity induced by flow variation, we spawned and reared individuals from both habitats types in flow and no flow conditions. Body shape significantly and consistently diverged in reservoir habitats compared with streams; individuals from reservoirs were shallower bodied with smaller heads compared with individuals from streams. Significant population-level differences in morphology persisted in offspring but morphological variation compared with field-collected individuals was limited to the head region. Populations demonstrated dissimilar flow-induced phenotypic plasticity when reared under flow, but phenotypic plasticity in response to flow variation was an unlikely explanation for observed phenotypic divergence in the field. Our results, together with previous investigations, suggest the environmental conditions currently thought to drive morphological change in reservoirs (i.e., predation and flow regimes) may not be the sole drivers of phenotypic change.

Reliance on lakes by salmon, trout and charr (Oncorhynchus,SalmoandSalvelinus): An evaluation of spawning habitats, rearing strategies and trophic polymorphisms

“…Furthermore, the use of lotic versus lentic waters may induce phenotypic plasticity (e.g. blacktail shiner, Cyprinella venusta , Cyprinidae—Franssen, Stewart, & Schaefer, ), evolutionary diversification (e.g. stream‐lake pairs of three‐spine stickleback, Gasterosteus aculeatus , Gasterosteidae—Deagle et al., ), and population structure (e.g.…”

Linking stream ecology with morphological variability in a native freshwater fish from semi‐arid Australia

“…We found some evidence that fish have altered their morphology in a creek affected by mine dewatering; however, further study is required before we can establish whether this provides an example of morphological responses to anthropogenic habitat alteration (Franssen ; Franssen et al. , ).…”

“…; Franssen ; Franssen et al. , ), further sampling of streams receiving high rates of discharge is required to determine whether the apparent morphological response observed here can be generalized.…”

Heterochromatin Polymorphism and Physical Mapping of 5S and 18S Ribosomal DNA in Four Populations ofHypostomus strigaticeps(Regan, 1907) from the Paraná River Basin, Brazil: Evolutionary and Environmental Correlation

“…24 Correlations of environment factors, such as flow and noflow conditions, with morphometric variabilty have already been reported in Cyprinella venusta. 25,26 As H. strigaticeps inhabits medium to large river channels, the present article compared, through means of cytogenetic and morphometric analysis, two populations of medium rivers and two populations of large river channels to identify possible interpopulational chromosomal markers supporting the environmental and evolutionary trends.…”

“…2b and 4c, d). Additionally, the population from the Piquiri River had interstitial heterochromatic blocks, CMA 3 -/DAPI + , on pairs of acrocentric chromosomes26,29,31, and 35 (Figs. 2b and 4c, d).…”