Authors: Keyne Monro and Dustin J Marshall
Published in: Evolution, volume 67, issue 12 (December 2013)
Constraints on life-history traits, with their close links to fitness, are widely invoked as limits to niche expansion at most organiza- tional levels.
Theoretically, such constraints can maintain individual specialization by preventing adaptation to all niches available, but empirical evidence of them remains elusive for natural populations. This problem may be compounded by a tendency to seek constraints involving multiple traits, neglecting their added potential to manifest in trait expression across environments (i.e., within reaction norms).
By replicating genotypes of a colonial marine invertebrate across successional stages in its local community, and taking a holistic approach to the analysis of ensuing reaction norms for fitness, we show the potential for individual specialization to be maintained by genetic constraints associated with these norms, which limit the potential for fitness at one successional stage to improve without loss of fitness at others.
Our study provides new insight into the evolutionary maintenance of individual specialization in natural populations and reinforces the importance of reaction norms for studying this phenomenon.
Monro K, Marshall DJ (2013) Evolutionary constraints and the maintenance of individual specialization throughout succession. Evolution 67(12): 3676–3644 PDF 495 KB doi:10.1111/evo.12220
Authors: Simon P Hart, Jacqueline R Burgin and Dustin J Marshall
Published in: Ecology, volume 93, issue 9, doi: 10.1890/11-2248.1
Formal links between theory and data are a critical goal for ecology. However, while our current understanding of competition provides the foundation for solving many derived ecological problems, this understanding is fractured because competition theory and data are rarely unified.
Conclusions from seminal studies in space-limited benthic marine systems, in particular, have been very influential for our general understanding of competition, but rely on traditional empirical methods with limited inferential power and compatibility with theory.
Here we explicitly link mathematical theory with experimental field data to provide a more sophisticated understanding of competition in this classic model system. In contrast to predictions from conceptual models, our estimates of competition coefficients show that a dominant space competitor can be equally affected by interspecific competition with a poor competitor (traditionally defined) as it is by intraspecific competition.
More generally, the often-invoked competitive hierarchies and intransitivities in this system might be usefully revisited using more sophisticated empirical and analytical approaches.
Hart SP, Burgin JR, Marshall DJ (2012) Revisiting competition in a classic model system using formal links between theory and data. Ecology, 93(9) 2015–2022 PDF 777 KB doi: 10.1890/11-2248.1