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Predicting species establishment using absent species and functional neighborhoods

View Article: PubMed Central - PubMed

ABSTRACT

Species establishment within a community depends on their interactions with the local environment and resident community. Such environmental and biotic filtering is frequently inferred from functional trait and phylogenetic patterns within communities; these patterns may also predict which additional species can establish. However, differentiating between environmental and biotic filtering can be challenging, which may complicate establishment predictions. Creating a habitat‐specific species pool by identifying which absent species within the region can establish in the focal habitat allows us to isolate biotic filtering by modeling dissimilarity between the observed and biotically excluded species able to pass environmental filters. Similarly, modeling the dissimilarity between the habitat‐specific species pool and the environmentally excluded species within the region can isolate local environmental filters. Combined, these models identify potentially successful phenotypes and why certain phenotypes were unsuccessful. Here, we present a framework that uses the functional dissimilarity among these groups in logistic models to predict establishment of additional species. This approach can use multivariate trait distances and phylogenetic information, but is most powerful when using individual traits and their interactions. It also requires an appropriate distance‐based dissimilarity measure, yet the two most commonly used indices, nearest neighbor (one species) and mean pairwise (all species) distances, may inaccurately predict establishment. By iteratively increasing the number of species used to measure dissimilarity, a functional neighborhood can be chosen that maximizes the detection of underlying trait patterns. We tested this framework using two seed addition experiments in calcareous grasslands. Although the functional neighborhood size that best fits the community's trait structure depended on the type of filtering considered, selecting these functional neighborhood sizes allowed our framework to predict up to 50% of the variation in actual establishment from seed. These results indicate that the proposed framework may be a powerful tool for studying and predicting species establishment.

No MeSH data available.


Related in: MedlinePlus

A hypothetical example using simulated data to show the differences between multivariate and individual trait approaches to predicting establishment within a single community. White circles represent species present in the community, gray circles species excluded through biotic interactions, and letters different potential colonists. Traits are randomly generated to represent regrowth potential which represents response to herbivory, and rooting depth which represents water acquisition strategies. Here, species within the community exhibit similar traits relating to herbivory tolerance (a, c), but segregate themselves according to water uptake strategies (a, d). Multivariate analyses are unlikely to detect limiting similarity in this scenario (b). Separately analyzing herbivory tolerance (c, e) and water acquisition strategy (d, f) makes the patterns easier to discern (e, f). Species A and B are likely to establish as they root at different depths than the species already within the community and have high herbivory tolerance. The other species are likely to fail: species C has no available water niche, species D cannot tolerate herbivory, and species E does not possess either required characteristic
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ece32804-fig-0004: A hypothetical example using simulated data to show the differences between multivariate and individual trait approaches to predicting establishment within a single community. White circles represent species present in the community, gray circles species excluded through biotic interactions, and letters different potential colonists. Traits are randomly generated to represent regrowth potential which represents response to herbivory, and rooting depth which represents water acquisition strategies. Here, species within the community exhibit similar traits relating to herbivory tolerance (a, c), but segregate themselves according to water uptake strategies (a, d). Multivariate analyses are unlikely to detect limiting similarity in this scenario (b). Separately analyzing herbivory tolerance (c, e) and water acquisition strategy (d, f) makes the patterns easier to discern (e, f). Species A and B are likely to establish as they root at different depths than the species already within the community and have high herbivory tolerance. The other species are likely to fail: species C has no available water niche, species D cannot tolerate herbivory, and species E does not possess either required characteristic

Mentions: The benefit of using an individual trait approach can be demonstrated using a hypothetical community that is structured by both herbivory and competition for water, with the two processes acting on distinct traits. If herbivory tolerance is required for persistence, species in the community should be similar in related traits (e.g., regrowth capacity) and the trait values will be clustered relative to absent species (Figure 4a). If differentiation in water acquisition is also important, coexisting species should be dissimilar in related traits (e.g., rooting depth) and the trait values dispersed (Figure 4a). As such, colonists with high regrowth potential and a dissimilar rooting depth are most likely to establish, while colonists with only one of these characteristics or neither characteristic are far less likely to establish (Figure 4). In this scenario, multivariate Euclidean distances that combine both traits did not effectively predict establishment (Figure 4b). Similarly, if both traits are conserved, phylogenetic approaches would be unlikely to detect any pattern. However, by using the individual traits as independent predictors in the model, we detected the pattern in both traits (Figure 4c,d), indicating that an individual trait approach may be most appropriate.


Predicting species establishment using absent species and functional neighborhoods
A hypothetical example using simulated data to show the differences between multivariate and individual trait approaches to predicting establishment within a single community. White circles represent species present in the community, gray circles species excluded through biotic interactions, and letters different potential colonists. Traits are randomly generated to represent regrowth potential which represents response to herbivory, and rooting depth which represents water acquisition strategies. Here, species within the community exhibit similar traits relating to herbivory tolerance (a, c), but segregate themselves according to water uptake strategies (a, d). Multivariate analyses are unlikely to detect limiting similarity in this scenario (b). Separately analyzing herbivory tolerance (c, e) and water acquisition strategy (d, f) makes the patterns easier to discern (e, f). Species A and B are likely to establish as they root at different depths than the species already within the community and have high herbivory tolerance. The other species are likely to fail: species C has no available water niche, species D cannot tolerate herbivory, and species E does not possess either required characteristic
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5383500&req=5

ece32804-fig-0004: A hypothetical example using simulated data to show the differences between multivariate and individual trait approaches to predicting establishment within a single community. White circles represent species present in the community, gray circles species excluded through biotic interactions, and letters different potential colonists. Traits are randomly generated to represent regrowth potential which represents response to herbivory, and rooting depth which represents water acquisition strategies. Here, species within the community exhibit similar traits relating to herbivory tolerance (a, c), but segregate themselves according to water uptake strategies (a, d). Multivariate analyses are unlikely to detect limiting similarity in this scenario (b). Separately analyzing herbivory tolerance (c, e) and water acquisition strategy (d, f) makes the patterns easier to discern (e, f). Species A and B are likely to establish as they root at different depths than the species already within the community and have high herbivory tolerance. The other species are likely to fail: species C has no available water niche, species D cannot tolerate herbivory, and species E does not possess either required characteristic
Mentions: The benefit of using an individual trait approach can be demonstrated using a hypothetical community that is structured by both herbivory and competition for water, with the two processes acting on distinct traits. If herbivory tolerance is required for persistence, species in the community should be similar in related traits (e.g., regrowth capacity) and the trait values will be clustered relative to absent species (Figure 4a). If differentiation in water acquisition is also important, coexisting species should be dissimilar in related traits (e.g., rooting depth) and the trait values dispersed (Figure 4a). As such, colonists with high regrowth potential and a dissimilar rooting depth are most likely to establish, while colonists with only one of these characteristics or neither characteristic are far less likely to establish (Figure 4). In this scenario, multivariate Euclidean distances that combine both traits did not effectively predict establishment (Figure 4b). Similarly, if both traits are conserved, phylogenetic approaches would be unlikely to detect any pattern. However, by using the individual traits as independent predictors in the model, we detected the pattern in both traits (Figure 4c,d), indicating that an individual trait approach may be most appropriate.

View Article: PubMed Central - PubMed

ABSTRACT

Species establishment within a community depends on their interactions with the local environment and resident community. Such environmental and biotic filtering is frequently inferred from functional trait and phylogenetic patterns within communities; these patterns may also predict which additional species can establish. However, differentiating between environmental and biotic filtering can be challenging, which may complicate establishment predictions. Creating a habitat‐specific species pool by identifying which absent species within the region can establish in the focal habitat allows us to isolate biotic filtering by modeling dissimilarity between the observed and biotically excluded species able to pass environmental filters. Similarly, modeling the dissimilarity between the habitat‐specific species pool and the environmentally excluded species within the region can isolate local environmental filters. Combined, these models identify potentially successful phenotypes and why certain phenotypes were unsuccessful. Here, we present a framework that uses the functional dissimilarity among these groups in logistic models to predict establishment of additional species. This approach can use multivariate trait distances and phylogenetic information, but is most powerful when using individual traits and their interactions. It also requires an appropriate distance‐based dissimilarity measure, yet the two most commonly used indices, nearest neighbor (one species) and mean pairwise (all species) distances, may inaccurately predict establishment. By iteratively increasing the number of species used to measure dissimilarity, a functional neighborhood can be chosen that maximizes the detection of underlying trait patterns. We tested this framework using two seed addition experiments in calcareous grasslands. Although the functional neighborhood size that best fits the community's trait structure depended on the type of filtering considered, selecting these functional neighborhood sizes allowed our framework to predict up to 50% of the variation in actual establishment from seed. These results indicate that the proposed framework may be a powerful tool for studying and predicting species establishment.

No MeSH data available.


Related in: MedlinePlus