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Phylogenetic conservatism of environmental niches in mammals.

Cooper N, Freckleton RP, Jetz W - Proc. Biol. Sci. (2011)

Bottom Line: Partitioning niche conservatism into its spatial and phylogenetic components, we find that spatial effects on niche variables are generally greater than phylogenetic effects.This suggests that recent evolution and dispersal have more influence on species' niches than more distant evolutionary events.These results have implications for our understanding of the role of niche conservatism in species richness patterns and for gauging the potential for species to adapt to global change.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8106, USA. nataliecooper@fas.harvard.edu

ABSTRACT
Phylogenetic niche conservatism is the pattern where close relatives occupy similar niches, whereas distant relatives are more dissimilar. We suggest that niche conservatism will vary across clades in relation to their characteristics. Specifically, we investigate how conservatism of environmental niches varies among mammals according to their latitude, range size, body size and specialization. We use the Brownian rate parameter, σ(2), to measure the rate of evolution in key variables related to the ecological niche and define the more conserved group as the one with the slower rate of evolution. We find that tropical, small-ranged and specialized mammals have more conserved thermal niches than temperate, large-ranged or generalized mammals. Partitioning niche conservatism into its spatial and phylogenetic components, we find that spatial effects on niche variables are generally greater than phylogenetic effects. This suggests that recent evolution and dispersal have more influence on species' niches than more distant evolutionary events. These results have implications for our understanding of the role of niche conservatism in species richness patterns and for gauging the potential for species to adapt to global change.

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Bar charts showing estimates of φ (white) and λ′ (grey) for each environmental variable in (a) temperate and tropical, (b) large- and small-geographical ranged, (c) large- and small-bodied, and (d) generalist and specialist mammals. P, precipitation; T, temperature; min, minimum; var, variability. Asterisk denotes value of non-spatially corrected λ. The dotted line indicates the maximum value of each parameter. Note that since φ, λ′ and γ sum to one, there is no need to display the γ values.
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RSPB20102207F1: Bar charts showing estimates of φ (white) and λ′ (grey) for each environmental variable in (a) temperate and tropical, (b) large- and small-geographical ranged, (c) large- and small-bodied, and (d) generalist and specialist mammals. P, precipitation; T, temperature; min, minimum; var, variability. Asterisk denotes value of non-spatially corrected λ. The dotted line indicates the maximum value of each parameter. Note that since φ, λ′ and γ sum to one, there is no need to display the γ values.

Mentions: Estimated φ, λ′ and γ values for all species in the phylogeny were as follows: mean precipitation: φ = 0.852, λ′ = 0.129, γ = 0.019; minimum precipitation: φ = 0.717, λ′ = 0.196, γ = 0.087; precipitation variability: φ = 0.662, λ′ = 0.168, γ = 0.170; all temperature variables: φ = 0.990, λ′ = 0.010, γ < 0.001 (using a fully resolved phylogeny: mean precipitation: φ = 0.764, λ′ = 0.213, γ = 0.023; minimum precipitation: φ = 0.661, λ′ = 0.297, γ = 0.092; precipitation variability: φ = 0.557, λ′ = 0.210, γ = 0.234; all temperature variables: φ = 0.990, λ′ = 0.010, γ < 0.001). These φ values are much higher than λ′ values, indicating that spatial effects on the environmental variables were greater than the purely phylogenetic effects. φ and λ′ values for the three groupings in this study are shown in figure 1 (note that since φ, λ′ and γ sum to one, there is no need to display the γ values, so we omit them to simplify the figures; electronic supplementary material, appendix A, figure A1 shows the results using a fully resolved phylogeny that excludes species with polytomies). Across the four subgroups and all six variables, values of φ are generally much higher than values of λ′, except for precipitation variables in temperate species where λ′ values are higher (figure 1; electronic supplementary material, appendix A and figures A1 and A2). We note that simultaneously accounting for spatial non-independence yields dramatically lowered estimates of the phylogenetic signal than if λ was quantified non-spatially (figure 1). λ and λ′ are correlated but not perfectly (all variables, 16 orders: ρ = 0.252; p = 0.013).Figure 1.


Phylogenetic conservatism of environmental niches in mammals.

Cooper N, Freckleton RP, Jetz W - Proc. Biol. Sci. (2011)

Bar charts showing estimates of φ (white) and λ′ (grey) for each environmental variable in (a) temperate and tropical, (b) large- and small-geographical ranged, (c) large- and small-bodied, and (d) generalist and specialist mammals. P, precipitation; T, temperature; min, minimum; var, variability. Asterisk denotes value of non-spatially corrected λ. The dotted line indicates the maximum value of each parameter. Note that since φ, λ′ and γ sum to one, there is no need to display the γ values.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3119006&req=5

RSPB20102207F1: Bar charts showing estimates of φ (white) and λ′ (grey) for each environmental variable in (a) temperate and tropical, (b) large- and small-geographical ranged, (c) large- and small-bodied, and (d) generalist and specialist mammals. P, precipitation; T, temperature; min, minimum; var, variability. Asterisk denotes value of non-spatially corrected λ. The dotted line indicates the maximum value of each parameter. Note that since φ, λ′ and γ sum to one, there is no need to display the γ values.
Mentions: Estimated φ, λ′ and γ values for all species in the phylogeny were as follows: mean precipitation: φ = 0.852, λ′ = 0.129, γ = 0.019; minimum precipitation: φ = 0.717, λ′ = 0.196, γ = 0.087; precipitation variability: φ = 0.662, λ′ = 0.168, γ = 0.170; all temperature variables: φ = 0.990, λ′ = 0.010, γ < 0.001 (using a fully resolved phylogeny: mean precipitation: φ = 0.764, λ′ = 0.213, γ = 0.023; minimum precipitation: φ = 0.661, λ′ = 0.297, γ = 0.092; precipitation variability: φ = 0.557, λ′ = 0.210, γ = 0.234; all temperature variables: φ = 0.990, λ′ = 0.010, γ < 0.001). These φ values are much higher than λ′ values, indicating that spatial effects on the environmental variables were greater than the purely phylogenetic effects. φ and λ′ values for the three groupings in this study are shown in figure 1 (note that since φ, λ′ and γ sum to one, there is no need to display the γ values, so we omit them to simplify the figures; electronic supplementary material, appendix A, figure A1 shows the results using a fully resolved phylogeny that excludes species with polytomies). Across the four subgroups and all six variables, values of φ are generally much higher than values of λ′, except for precipitation variables in temperate species where λ′ values are higher (figure 1; electronic supplementary material, appendix A and figures A1 and A2). We note that simultaneously accounting for spatial non-independence yields dramatically lowered estimates of the phylogenetic signal than if λ was quantified non-spatially (figure 1). λ and λ′ are correlated but not perfectly (all variables, 16 orders: ρ = 0.252; p = 0.013).Figure 1.

Bottom Line: Partitioning niche conservatism into its spatial and phylogenetic components, we find that spatial effects on niche variables are generally greater than phylogenetic effects.This suggests that recent evolution and dispersal have more influence on species' niches than more distant evolutionary events.These results have implications for our understanding of the role of niche conservatism in species richness patterns and for gauging the potential for species to adapt to global change.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8106, USA. nataliecooper@fas.harvard.edu

ABSTRACT
Phylogenetic niche conservatism is the pattern where close relatives occupy similar niches, whereas distant relatives are more dissimilar. We suggest that niche conservatism will vary across clades in relation to their characteristics. Specifically, we investigate how conservatism of environmental niches varies among mammals according to their latitude, range size, body size and specialization. We use the Brownian rate parameter, σ(2), to measure the rate of evolution in key variables related to the ecological niche and define the more conserved group as the one with the slower rate of evolution. We find that tropical, small-ranged and specialized mammals have more conserved thermal niches than temperate, large-ranged or generalized mammals. Partitioning niche conservatism into its spatial and phylogenetic components, we find that spatial effects on niche variables are generally greater than phylogenetic effects. This suggests that recent evolution and dispersal have more influence on species' niches than more distant evolutionary events. These results have implications for our understanding of the role of niche conservatism in species richness patterns and for gauging the potential for species to adapt to global change.

Show MeSH