Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

Costa‐Pereira, Raul; Tavares, Luiz Eduardo Roland; Camargo, Plínio Barbosa de; Araújo, Márcio S.

doi:10.1111/btp.12434

Cited by 50 publications

(52 citation statements)

References 49 publications

(96 reference statements)

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“…Surprisingly, the diversity of available resources did not explain variations in the degree of individual specialization. This contrasts with previous studies revealing an overall positive effect of ecological opportunity on diet variation because higher prey diversity creates more opportunity for individual diet variation by expanding individuals’ foraging options (Costa‐Pereira et al., ; Evangelista et al., ; Newsome et al., ). This discrepancy may simply arise because thin‐toed frogs are generalists which consume a wide variety of species.…”

Section: Discussioncontrasting

confidence: 82%

“…Furthermore, the majority of these studies focused on the specific effect of only one of these four ecological factors (e.g., intraspecific competition, Svanbäck & Persson, ; Svanbäck & Bolnick, ; Tinker, Bentall, & Estes, ). Only recently have observational studies started to provide some insights on how two ecological factors can interact to determine the degree of individual niche variation in populations (Costa‐Pereira, Tavares, de Camargo, & Araújo, ; Evangelista, Boiche, Lecerf, & Cucherousset, ; Newsome et al., ). However, under natural conditions, populations are usually facing all four factors simultaneously to varying degrees and the effects of these factors may not be independent.…”

Section: Introductionmentioning

confidence: 99%

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Drivers of individual niche variation in coexisting species

Costa‐Pereira

Rudolf

Souza

et al. 2018

Journal of Animal Ecology

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Although neglected by classic niche theory, individual variation is now recognized as a prevalent phenomenon in nature with evolutionary and ecological relevance. Recent theory suggests that differences in individual variation across competitors can affect species coexistence and community patterns. However, the degree of individual variation is flexible across wild populations and we still know little about the ecological drivers of this variation across populations of single species and, especially, across coexisting species. Here, we aimed to (a) elucidate the major drivers of individual niche variation in natural communities and (b) to determine how consistent this variation is across coexisting species and communities. We analysed natural patterns of individual-level niche variation in four species of coexisting generalist frogs across a wide range of tropical communities. Specifically, we used gut contents and stable isotopes (δ C and δ N) from frog species and their prey to quantify individual niche specialization. Then, we combined data on local community structure, availability of prey, phylogenetic relationships and predator-prey size models to test how this variation is related to four ecological factors which are predicted to be key drivers of individual specialization: intraspecific competition, interspecific competition, ecological opportunity (i.e., diversity of resources) and predation. We found that the degree of individual trophic specialization varied by up to ninefold across populations within the same species. This sizable variation in trophic specialization across populations was at least partially explained by gradients of density of competitors (both conspecifics and heterospecifics) and intraguild predation. However, the specific relationships between individual specialization and these ecological gradients were strongly species-specific. As consequences, the identity of the species with more individual variation changed among sites and there was typically no spatial correlation in the degree of individual specialization across coexisting species. Our results show that individual niche specialization within and across species can be strongly context-dependent and that hierarchies of individual variation among coexisting species are not necessarily consistent across communities. Recent theory suggests that this pattern could lead to concurrent changes in competitive interactions across sites and thereby could play a key role in species coexistence at the landscape level. Our results suggest that individual variation across and within coexisting species has the potential to affect not only species coexistence at local communities, but also regional diversity patterns.

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Section: Discussioncontrasting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Drivers of individual niche variation in coexisting species

Costa‐Pereira

Rudolf

Souza

et al. 2018

Journal of Animal Ecology

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“…, Costa‐Pereira et al. ). From a whole food web perspective, preventing extinction is inarguably a component of stability.…”

Section: Discussionmentioning

confidence: 99%

“…Recent work using stable isotopes (δ 15 N and δ 13 C) supports this idea by demonstrating that fishes can become more generalized feeders during the wet season, likely reflecting increased access to a wider range of habitats and food resources while floodplains are inundated (Costa‐Pereira et al. , Pool et al. ).…”

Section: Introductionmentioning

confidence: 95%

Consumer trophic positions respond variably to seasonally fluctuating environments

McMeans

Kadoya

Pool

et al. 2019

Ecology

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The effects of environmental seasonality on food web structure have been notoriously understudied in empirical ecology. Here, we focus on seasonal changes in one key attribute of a food web, consumer trophic position. We ask whether fishes inhabiting tropical river–floodplain ecosystems behave as seasonal omnivores, by shifting their trophic positions in relation to the annual flood pulse, or whether they feed at the same trophic position all year, as much empirical work implicitly assumes. Using dietary data from the Tonle Sap Lake, Cambodia, and a literature review, we find evidence that some fishes, especially small piscivores, increased consumption of invertebrates and/or plant material during the wet season, as predicted. However, nitrogen stable isotope (δ15N) data for 26 Tonle Sap fishes, spanning a broader range of functional groups, uncovered high variation in seasonal trophic position responses among species (0 to ±0.52 trophic positions). Based on these findings, species respond to the flood pulse differently. Diverse behavioral responses to seasonality, underpinned by spatiotemporal variation at multiple scales, could be central for rerouting matter and energy flow in these dynamic ecosystems. Seasonally flexible foraging behaviors warrant further study given their potential influence on food web dynamics in a range of fluctuating environments.

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“…However, these predictions only hold when resource availability is high and stable. Other ecological contexts, such as temporal fluctuations in prey availability and competition for highly profitable resources, may reduce the benefits of temporal diet consistency (Costa‐Pereira, Tavares, Camargo, & Araújo, ; Svanbäck & Bolnick, , ), and instead favour generalist foraging strategies that provide access to a wider range and quantity of resources (Roughgarden, ; Van Valen, ).…”

Section: Introductionmentioning

confidence: 99%

Individual niche trajectories drive fitness variation

et al. 2019

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Variation in fitness across individuals is central to population growth, species coexistence and evolution by natural selection. Fitness variation associated with resource use is hugely consequential, but how this variation is generated and maintained within natural populations remains unclear. In particular, individual fitness may depend on many cumulative foraging decisions over time, but this hypothesis remains untested. We used multi‐tissue stable isotope analysis to determine isotopic niche trajectories within species, populations and sexes of thin‐toed frogs and explored how this temporal dimension of diet affects individual reproductive investment, body condition and parasite load. We found that individual frogs shifted their diets less than expected under a null model, likely due to functional trade‐offs that limit the incorporation of new prey types over time. However, within the observed range of diet shifts, individuals that modified their diet to a greater degree exhibited higher fitness, although this effect was sex‐dependent. We suggest that these different relationships between isotopic niche trajectory length and fitness within thin‐toed frogs are driven by variability in the resource environment, negative density dependence and allometric constraints. These strong fitness effects suggest that the temporal dimension of diet change is a potential target of natural selection and, therefore, could drive correlated evolution in phenotypic traits underlying diet flexibility. Our findings add a new level of complexity to the understanding of ecological and evolutionary consequences of niche variation by demonstrating that temporal variation in foraging consistency within populations leads to different fitness pay‐offs. A free Plain Language Summary can be found within the Supporting Information of this article.

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Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

Cited by 50 publications

References 49 publications

Drivers of individual niche variation in coexisting species

Drivers of individual niche variation in coexisting species

Consumer trophic positions respond variably to seasonally fluctuating environments

Individual niche trajectories drive fitness variation

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