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Ecosystem fragmentation drives increased diet variation in an endemic livebearing fish of the Bahamas.

Araújo MS, Langerhans RB, Giery ST, Layman CA - Ecol Evol (2014)

Bottom Line: We took advantage of this environmental gradient to investigate effects of ecosystem fragmentation on patterns of resource use in the livebearing fish Gambusia hubbsi (Family Poeciliidae), using both population- and individual-level perspectives.We show that fragmentation-induced release from predation led to increased G. hubbsi population densities, which consequently led to lower mean growth rates, likely as a result of higher intraspecific competition for food.Our results therefore indicate that habitat fragmentation can greatly impact the ecology of resilient populations, with potentially important ecological and evolutionary implications.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ecologia, Instituto de Biociências, Universidade Estadual Paulista "Julio de Mesquita Filho" Rio Claro, Sao Paulo, 13506-900, Brazil.

ABSTRACT
One consequence of human-driven habitat degradation in general, and habitat fragmentation in particular, is loss of biodiversity. An often-underappreciated aspect of habitat fragmentation relates to changes in the ecology of species that persist in altered habitats. In Bahamian wetlands, ecosystem fragmentation causes disruption of hydrological connectivity between inland fragmented wetlands and adjacent marine areas, with the consequent loss of marine piscivores from fragmented sections. We took advantage of this environmental gradient to investigate effects of ecosystem fragmentation on patterns of resource use in the livebearing fish Gambusia hubbsi (Family Poeciliidae), using both population- and individual-level perspectives. We show that fragmentation-induced release from predation led to increased G. hubbsi population densities, which consequently led to lower mean growth rates, likely as a result of higher intraspecific competition for food. This was accompanied by a broadening of dietary niches via increased interindividual diet variation, suggesting a negative effect of predation and a positive effect of intraspecific competition on the degree of diet variation in natural populations. Our results therefore indicate that habitat fragmentation can greatly impact the ecology of resilient populations, with potentially important ecological and evolutionary implications.

No MeSH data available.


Related in: MedlinePlus

Diet composition of the 13 analyzed populations. Populations were pooled together according to level of connectivity (colors follow Figure 2). Diets are represented as the proportions of the number of prey items consumed.
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fig03: Diet composition of the 13 analyzed populations. Populations were pooled together according to level of connectivity (colors follow Figure 2). Diets are represented as the proportions of the number of prey items consumed.

Mentions: We found that habitat fragmentation of Bahamian tidal creeks caused a sharp decrease in piscivore and an increase in Gambusia densities (Table 2). This trend was accompanied by an overall decrease in growth rates in fragmented areas. Diet variation tended to be higher in fragmented areas, which was associated with a shift from a diet mainly composed of copepods to the inclusion of additional aquatic and allochthonous invertebrates (Fig. 3).


Ecosystem fragmentation drives increased diet variation in an endemic livebearing fish of the Bahamas.

Araújo MS, Langerhans RB, Giery ST, Layman CA - Ecol Evol (2014)

Diet composition of the 13 analyzed populations. Populations were pooled together according to level of connectivity (colors follow Figure 2). Diets are represented as the proportions of the number of prey items consumed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222216&req=5

fig03: Diet composition of the 13 analyzed populations. Populations were pooled together according to level of connectivity (colors follow Figure 2). Diets are represented as the proportions of the number of prey items consumed.
Mentions: We found that habitat fragmentation of Bahamian tidal creeks caused a sharp decrease in piscivore and an increase in Gambusia densities (Table 2). This trend was accompanied by an overall decrease in growth rates in fragmented areas. Diet variation tended to be higher in fragmented areas, which was associated with a shift from a diet mainly composed of copepods to the inclusion of additional aquatic and allochthonous invertebrates (Fig. 3).

Bottom Line: We took advantage of this environmental gradient to investigate effects of ecosystem fragmentation on patterns of resource use in the livebearing fish Gambusia hubbsi (Family Poeciliidae), using both population- and individual-level perspectives.We show that fragmentation-induced release from predation led to increased G. hubbsi population densities, which consequently led to lower mean growth rates, likely as a result of higher intraspecific competition for food.Our results therefore indicate that habitat fragmentation can greatly impact the ecology of resilient populations, with potentially important ecological and evolutionary implications.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ecologia, Instituto de Biociências, Universidade Estadual Paulista "Julio de Mesquita Filho" Rio Claro, Sao Paulo, 13506-900, Brazil.

ABSTRACT
One consequence of human-driven habitat degradation in general, and habitat fragmentation in particular, is loss of biodiversity. An often-underappreciated aspect of habitat fragmentation relates to changes in the ecology of species that persist in altered habitats. In Bahamian wetlands, ecosystem fragmentation causes disruption of hydrological connectivity between inland fragmented wetlands and adjacent marine areas, with the consequent loss of marine piscivores from fragmented sections. We took advantage of this environmental gradient to investigate effects of ecosystem fragmentation on patterns of resource use in the livebearing fish Gambusia hubbsi (Family Poeciliidae), using both population- and individual-level perspectives. We show that fragmentation-induced release from predation led to increased G. hubbsi population densities, which consequently led to lower mean growth rates, likely as a result of higher intraspecific competition for food. This was accompanied by a broadening of dietary niches via increased interindividual diet variation, suggesting a negative effect of predation and a positive effect of intraspecific competition on the degree of diet variation in natural populations. Our results therefore indicate that habitat fragmentation can greatly impact the ecology of resilient populations, with potentially important ecological and evolutionary implications.

No MeSH data available.


Related in: MedlinePlus