Limits...
Niche partitioning and the role of intraspecific niche variation in structuring a guild of generalist anurans

View Article: PubMed Central - PubMed

ABSTRACT

Intra-population niche differences in generalist foragers have captured the interest of ecologists, because such individuality can have important ecological and evolutionary implications. Few researchers have investigated how these differences affect the relationships among ecologically similar, sympatric species. Using stable isotopes, stomach contents, morphology and habitat preference, we examined niche partitioning within a group of five anurans and determined whether variation within species could facilitate resource partitioning. Species partitioned their niches by trophic level and by foraging habitat. However, there was considerable intraspecific variation in trophic level, with larger individuals generally feeding at higher trophic levels. For species at intermediate trophic levels, smaller individuals overlapped in trophic level with individuals of smaller species and larger individuals overlapped with the smallest individuals from larger species. Species varied in carbon isotopes; species with enriched carbon isotope ratios foraged farther from ponds, whereas species with depleted carbon isotope values foraged closer to ponds. Our study shows that these species partition their niches by feeding at different trophic levels and foraging at different distances from ponds. The intraspecific variation in trophic level decreased the number of individuals from each species that overlapped in trophic level with individuals from other species, which can facilitate species coexistence.

No MeSH data available.


Related in: MedlinePlus

(a) δ15N values and (b) δ13C values and versus SVL for each species. Each species is represented by the colour in legend in panel (a). Lines for each species are represented by the same colour symbol and are the general linear models. Increasing δ15N values with SVL within species demonstrates how intraspecific variation can aid resource partitioning, as overlap in trophic niche is size-dependent. Smaller individuals within a species overlap in trophic niche with a different set of other species than larger individuals. This is particularly pronounced in L. clamitans and L. catesbeianus. Each region is represented by a differently shaped symbol: North (squares), North Central (circles), South (triangles), South Central (diamonds). Lines represent the slope of the regression without being nested for each site.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5383860&req=5

RSOS170060F3: (a) δ15N values and (b) δ13C values and versus SVL for each species. Each species is represented by the colour in legend in panel (a). Lines for each species are represented by the same colour symbol and are the general linear models. Increasing δ15N values with SVL within species demonstrates how intraspecific variation can aid resource partitioning, as overlap in trophic niche is size-dependent. Smaller individuals within a species overlap in trophic niche with a different set of other species than larger individuals. This is particularly pronounced in L. clamitans and L. catesbeianus. Each region is represented by a differently shaped symbol: North (squares), North Central (circles), South (triangles), South Central (diamonds). Lines represent the slope of the regression without being nested for each site.

Mentions: To examine the relationship between isotope types and SVL for each species, we used GLMM in which region was a random factor. When differences in isotope values among regions had been accounted for, individuals of A. americanus, L. clamitans and L. catesbeianus with longer SVL had more enriched δ15N values (table 1 and figure 3a). However, SVL did not have a significant effect on δ15N values in A. fowleri or L. sphenocephalus (table 1 and figure 3a). Individuals of A. americanus and L. catesbeianus with longer SVL also had more enriched δ13C values (table 1 and figure 3b), but SVL did not significantly affect δ13C values in A. fowleri, L. sphenocephalus or L. clamitans (table 1 and figure 3b).Figure 3.


Niche partitioning and the role of intraspecific niche variation in structuring a guild of generalist anurans
(a) δ15N values and (b) δ13C values and versus SVL for each species. Each species is represented by the colour in legend in panel (a). Lines for each species are represented by the same colour symbol and are the general linear models. Increasing δ15N values with SVL within species demonstrates how intraspecific variation can aid resource partitioning, as overlap in trophic niche is size-dependent. Smaller individuals within a species overlap in trophic niche with a different set of other species than larger individuals. This is particularly pronounced in L. clamitans and L. catesbeianus. Each region is represented by a differently shaped symbol: North (squares), North Central (circles), South (triangles), South Central (diamonds). Lines represent the slope of the regression without being nested for each site.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383860&req=5

RSOS170060F3: (a) δ15N values and (b) δ13C values and versus SVL for each species. Each species is represented by the colour in legend in panel (a). Lines for each species are represented by the same colour symbol and are the general linear models. Increasing δ15N values with SVL within species demonstrates how intraspecific variation can aid resource partitioning, as overlap in trophic niche is size-dependent. Smaller individuals within a species overlap in trophic niche with a different set of other species than larger individuals. This is particularly pronounced in L. clamitans and L. catesbeianus. Each region is represented by a differently shaped symbol: North (squares), North Central (circles), South (triangles), South Central (diamonds). Lines represent the slope of the regression without being nested for each site.
Mentions: To examine the relationship between isotope types and SVL for each species, we used GLMM in which region was a random factor. When differences in isotope values among regions had been accounted for, individuals of A. americanus, L. clamitans and L. catesbeianus with longer SVL had more enriched δ15N values (table 1 and figure 3a). However, SVL did not have a significant effect on δ15N values in A. fowleri or L. sphenocephalus (table 1 and figure 3a). Individuals of A. americanus and L. catesbeianus with longer SVL also had more enriched δ13C values (table 1 and figure 3b), but SVL did not significantly affect δ13C values in A. fowleri, L. sphenocephalus or L. clamitans (table 1 and figure 3b).Figure 3.

View Article: PubMed Central - PubMed

ABSTRACT

Intra-population niche differences in generalist foragers have captured the interest of ecologists, because such individuality can have important ecological and evolutionary implications. Few researchers have investigated how these differences affect the relationships among ecologically similar, sympatric species. Using stable isotopes, stomach contents, morphology and habitat preference, we examined niche partitioning within a group of five anurans and determined whether variation within species could facilitate resource partitioning. Species partitioned their niches by trophic level and by foraging habitat. However, there was considerable intraspecific variation in trophic level, with larger individuals generally feeding at higher trophic levels. For species at intermediate trophic levels, smaller individuals overlapped in trophic level with individuals of smaller species and larger individuals overlapped with the smallest individuals from larger species. Species varied in carbon isotopes; species with enriched carbon isotope ratios foraged farther from ponds, whereas species with depleted carbon isotope values foraged closer to ponds. Our study shows that these species partition their niches by feeding at different trophic levels and foraging at different distances from ponds. The intraspecific variation in trophic level decreased the number of individuals from each species that overlapped in trophic level with individuals from other species, which can facilitate species coexistence.

No MeSH data available.


Related in: MedlinePlus