Macroalgal defense phenotype correlates with herbivore abundance
- PDF / 1,577,267 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 46 Downloads / 210 Views
ORIGINAL PAPER
Macroalgal defense phenotype correlates with herbivore abundance Scott S. Gabara1,2 · Benjamin P. Weitzman3,4 · Brenda H. Konar3 · Matthew S. Edwards1 Received: 27 April 2020 / Accepted: 13 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A primary goal in the study of producer–herbivore interactions is to characterize the tradeoffs between primary producer growth and defense. Across the Aleutian Island Archipelago, the widespread decline in sea otters has resulted in reduced predation on sea urchins, which has led to increases in urchin populations, the formation of urchin barrens, and ultimately to overgrazing of much of the region’s kelp forests. The occurrence of both kelp forests and urchin barrens on islands, along with among island variation in the time period that urchin barrens have formed, presents a unique opportunity to characterize the extent to which exposure to intense herbivory and increased light may alter marine macroalgal growth and defense tradeoffs. To address this, we used a field caging experiment with Codium ritteri, a common perennial green macroalga in the Aleutian Archipelago, to test whether urchin barren macroalgae exhibit increased defenses and reduced growth relative to kelp forest individuals. Our results suggest that urchin barren C. ritteri had greater defense than growth relative to kelp forest individuals. In the laboratory, we found little evidence for urchin barren C. ritteri growth under low light or altered defenses at high light. Grazing rates on C. ritteri were correlated with urchin biomass in the field suggesting higher herbivory intensity may shift primary producer energy allocation from growth to defense. Together, our data suggest that macroalgae occurring within kelp forests grow faster but are more palatable than macroalgae occurring in urchin barrens, which may increase urchin deforestation potential.
Introduction
Responsible Editor: F. Weinberger. Reviewed by undisclosed experts. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00227-020-03787-7) contains supplementary material, which is available to authorized users. * Scott S. Gabara [email protected] 1
Department of Biology and Coastal Marine Institute Laboratory, San Diego State University, San Diego, CA 92182, USA
2
Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA
3
College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
4
Kasitsna Bay Laboratory, NOAA, National Ocean Service, National Centers for Coastal Ocean Science, Homer, AK 99603, USA
Herbivory can play a central role in structuring primary producer communities in terrestrial and marine systems (Hairston et al. 1960; Gaines and Lubchenco 1982). In particular, herbivores can alter the distribution, abundance and fitness of primary producers, change how they allocate energy toward growth and defenses, and ultimately affect ecosystem structure
Data Loading...
