James T. Stroud

Is a community still a community? Reviewing definitions of key terms in community ecology

Abstract Community ecology is an inherently complicated field, confounded by the conflicting use of fundamental terms. Nearly two decades ago, Fauth et al. (1996) demonstrated that imprecise language led to the virtual synonymy of important terms and so attempted to clearly define four keywords in community ecology; “community,” “assemblage,” “guild,” and “ensemble”. We revisit Fauth et al.s conclusion and discuss how the use of these terms has changed over time since their review. An updated analysis of term definition from a selection of popular ecological textbooks suggests that definitions have drifted away from those encountered pre‐1996, and slightly disagreed with results from a survey of 100 ecology professionals (comprising of academic professors, nonacademic PhDs, graduate and undergraduate biology students). Results suggest that confusion about these terms is still widespread in ecology. We conclude with clear suggestions for definitions of each term to be adopted hereafter to provide greater cohesion among research groups.

Neglect of the Tropics Is Widespread in Ecology and Evolution: A Comment on Clarke et al.

Neglect of the tropics is a widespread problem across ecology and evolution, and not specific to the field of biodiversity and ecosystem function.

A downside of diversity? A response to Gallagher et al.

Gallagher et al. [1] propose that the niche breadth of a species is a potentially reliable predictor of extinction vulnerability. Species with narrow niches (specialists) generally have lower ecological resistances (i.e., are more sensitive to environmental disturbances) than similar species with broader niches (generalists). Gallagher et al. demonstrate this relationship between niche breadth and extinction vulnerability by highlighting the elevated extinction probabilities for specialist versus generalist species across a broad range of taxonomic groups.

The effects of thermal stress on the early development of the lizard Anolis sagrei

Across the globe terrestrial ectotherms-amphibians and non-avian reptiles-are facing a range of emerging challenges. Increasing global temperatures, in particular, are affecting all aspects of ectotherm biology and life history. Embryonic development is a thermally sensitive period of the organismal lifecycle, yet the impacts of thermal stress on the early development of ectotherms have significantly lagged behind studies of later stages and adult thermal physiology. Morphogenesis, the stage where the major anatomical systems are actively forming, is particularly sensitive to thermal stress, yet is not studied as often as later stages where growth is the primary process happening within the egg. Here, we focus on the effects of thermal stress on the first 12 days of development, the stages of morphogenesis, in the lizard Anolis sagrei. We examine the resiliency of the early developmental stages to heat stress by incubating eggs at temperatures that parallel conditions observed today and predicted over the next 50-100 years of projected climate change. Our results suggest that some anole nests are currently at the thermal limits for which the early embryonic stages can properly develop. Our results emphasize the importance of studying early embryonic stages of development and the importance of studying stage-specific effects of thermal stress on squamate development.

Ecological opportunity, competition, and diversity-dependence in macroevolution

The realization that adaptation can happen over observable time has accelerated our understanding of how competition can drive evolution. However, the extent to which competition influences macroevolutionary patterns remains a contentious issue. Classically, the relationship between competition and biodiversity dynamics was examined through the fossil record. More recently, reconstructed molecular phylogenies have provided an additional tool for modeling how species interactions may influence rates of species diversification and trait evolution. However, disentangling the processes of speciation from extinction using only information on extant lineages remains a major challenge (Marshall 2017). Progress in understanding the factors that influence rates of speciation and extinction is therefore integral to our understanding of how biological diversity is distributed and maintained at both regional and global scales (Rosenzweig 1995). Early in their existence, clades often undergo an initial burst of diversification. One explanation for this pattern is the hypothesis of “ecological opportunity,” where a species or clade presented with access to unexploited ecological resources rapidly expands in species abundance and ecological diversity (Schluter 2000). For example, colonization of the remote Hawaiian archipelago led to repeated diversification across a suite of plant and animal taxa, just as the colonization of landlocked African Rift Lakes was followed by the explosive diversification of freshwater cichlid fishes (Stroud and Losos 2016). After this initial burst of diversification, whether early in a clade’s existence or after encountering an ecological opportunity,

Digest: Ecological opportunity, competition, and diversity dependence in macroevolution*: DIGESTS

The realization that adaptation can happen over observable time has accelerated our understanding of how competition can drive evolution. However, the extent to which competition influences macroevolutionary patterns remains a contentious issue. Classically, the relationship between competition and biodiversity dynamics was examined through the fossil record. More recently, reconstructed molecular phylogenies have provided an additional tool for modeling how species interactions may influence rates of species diversification and trait evolution. However, disentangling the processes of speciation from extinction using only information on extant lineages remains a major challenge (Marshall 2017). Progress in understanding the factors that influence rates of speciation and extinction is therefore integral to our understanding of how biological diversity is distributed and maintained at both regional and global scales (Rosenzweig 1995). Early in their existence, clades often undergo an initial burst of diversification. One explanation for this pattern is the hypothesis of “ecological opportunity,” where a species or clade presented with access to unexploited ecological resources rapidly expands in species abundance and ecological diversity (Schluter 2000). For example, colonization of the remote Hawaiian archipelago led to repeated diversification across a suite of plant and animal taxa, just as the colonization of landlocked African Rift Lakes was followed by the explosive diversification of freshwater cichlid fishes (Stroud and Losos 2016). After this initial burst of diversification, whether early in a clade’s existence or after encountering an ecological opportunity,

Different evolutionary dynamics led to the convergence of clinging performance in lizard toepads

Does convergent evolution always result from different lineages experiencing similar evolutionary dynamics? Hagey et al (2017) report the dynamics of adhesive performance evolution to be distinct in two lizard clades (anoles and geckos) despite independent convergence in adhesive toe pad structures, suggesting convergence can occur with dissimilar macroevolutionary dynamics. This article is protected by copyright. All rights reserved