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Eco-evolution in size-structured ecosystems: simulation case study of rapid morphological changes in alewife
Jung Koo Kang1,2, Xavier Thibert-Plante3
1The Center for Quantitative Sciences in Biomedicine, North Carolina State University, Campus Box 8213, 308 Cox Hall, Raleigh, 27695-8212, NC, USA.
BMC Evolutionary Biology
|March 1, 2017
Summary
Alewife (Alosa pseudoharengus) landlocking caused rapid morphological changes, impacting both fish and prey. These evolutionary shifts may not represent a stable state, highlighting complex ecological interactions.
Area of Science:
- Ecology
- Evolutionary Biology
- Fisheries Science
Background:
- Alewife (Alosa pseudoharengus) populations have undergone rapid morphological transitions from anadromous to landlocked forms over 300 years due to lake interactions.
- Landlocked alewives exhibit smaller body sizes, earlier maturity, and altered feeding habits compared to their anadromous counterparts.
- These changes offer insights into fish morphological evolution, crucial for ecosystem and fisheries management.
Purpose of the Study:
- To understand the feedback mechanisms driving rapid morphological evolution in fish populations.
- To investigate how alewife populations impact prey communities and how these interactions influence alewife morphology.
- To predict the long-term evolutionary trajectories of landlocked alewives in freshwater environments.
Main Methods:
- Developed an individual-based model simulating changes in fish body size and gill-raker count.
- Utilized a functional trait approach to link prey body size, fish body size, and gill-raker count.
- Model parameters were informed by empirical data from alewife studies.
Main Results:
- Alewife gill-raker counts increased with body size reductions that enhanced foraging on small prey.
- Fish growth decreased while gill-raker number increased for the first 150-250 years.
- After 150-250 years, alewives showed diverse evolutionary trajectories, with some reversing, indicating complex responses to trophic settings.
Conclusions:
- Alewife morphology and abundance are influenced by prey community dynamics, creating feedback loops.
- Complex interactions at lower trophic levels significantly alter alewife characteristics.
- The current morphology of recently landlocked alewives may not be an evolutionarily stable state.
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