Browsing by Subject "Food Chain"

Now showing 1 - 4 of 4

Open Access
A unifying framework for interpreting and predicting mutualistic systems.
(Nature communications, 2019-01) Wu, Feilun; Lopatkin, Allison J; Needs, Daniel A; Lee, Charlotte T; Mukherjee, Sayan; You, Lingchong
Coarse-grained rules are widely used in chemistry, physics and engineering. In biology, however, such rules are less common and under-appreciated. This gap can be attributed to the difficulty in establishing general rules to encompass the immense diversity and complexity of biological systems. Furthermore, even when a rule is established, it is often challenging to map it to mechanistic details and to quantify these details. Here we report a framework that addresses these challenges for mutualistic systems. We first deduce a general rule that predicts the various outcomes of mutualistic systems, including coexistence and productivity. We further develop a standardized machine-learning-based calibration procedure to use the rule without the need to fully elucidate or characterize their mechanistic underpinnings. Our approach consistently provides explanatory and predictive power with various simulated and experimental mutualistic systems. Our strategy can pave the way for establishing and implementing other simple rules for biological systems.
Open Access
Climate drives the geography of marine consumption by changing predator communities.
(Proceedings of the National Academy of Sciences of the United States of America, 2020-11) Whalen, Matthew A; Whippo, Ross DB; Stachowicz, John J; York, Paul H; Aiello, Erin; Alcoverro, Teresa; Altieri, Andrew H; Benedetti-Cecchi, Lisandro; Bertolini, Camilla; Bresch, Midoli; Bulleri, Fabio; Carnell, Paul E; Cimon, Stéphanie; Connolly, Rod M; Cusson, Mathieu; Diskin, Meredith S; D’Souza, Elrika; Flores, Augusto AV; Fodrie, F Joel; Galloway, Aaron WE; Gaskins, Leo C; Graham, Olivia J; Hanley, Torrance C; Henderson, Christopher J; Hereu, Clara M; Hessing-Lewis, Margot; Hovel, Kevin A; Hughes, Brent B; Hughes, A Randall; Hultgren, Kristin M; Jänes, Holger; Janiak, Dean S; Johnston, Lane N; Jorgensen, Pablo; Kelaher, Brendan P; Kruschel, Claudia; Lanham, Brendan S; Lee, Kun-Seop; Lefcheck, Jonathan S; Lozano-Álvarez, Enrique; Macreadie, Peter I; Monteith, Zachary L; O’Connor, Nessa E; Olds, Andrew D; O’Leary, Jennifer K; Patrick, Christopher J; Pino, Oscar; Poore, Alistair GB; Rasheed, Michael A; Raymond, Wendel W; Reiss, Katrin; Rhoades, O Kennedy; Robinson, Max T; Ross, Paige G; Rossi, Francesca; Schlacher, Thomas A; Seemann, Janina; Silliman, Brian R; Smee, Delbert L; Thiel, Martin; Unsworth, Richard KF; van Tussenbroek, Brigitta I; Vergés, Adriana; Yeager, Mallarie E; Yednock, Bree K; Ziegler, Shelby L; Duffy, J Emmett
The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems.
Open Access
Eco-evolutionary trophic dynamics: loss of top predators drives trophic evolution and ecology of prey.
(PLoS One, 2011-04-19) Palkovacs, EP; Wasserman, BA; Kinnison, MT
Ecosystems are being altered on a global scale by the extirpation of top predators. The ecological effects of predator removal have been investigated widely; however, predator removal can also change natural selection acting on prey, resulting in contemporary evolution. Here we tested the role of predator removal on the contemporary evolution of trophic traits in prey. We utilized a historical introduction experiment where Trinidadian guppies (Poecilia reticulata) were relocated from a site with predatory fishes to a site lacking predators. To assess the trophic consequences of predator release, we linked individual morphology (cranial, jaw, and body) to foraging performance. Our results show that predator release caused an increase in guppy density and a "sharpening" of guppy trophic traits, which enhanced food consumption rates. Predator release appears to have shifted natural selection away from predator escape ability and towards resource acquisition ability. Related diet and mesocosm studies suggest that this shift enhances the impact of guppies on lower trophic levels in a fashion nuanced by the omnivorous feeding ecology of the species. We conclude that extirpation of top predators may commonly select for enhanced feeding performance in prey, with important cascading consequences for communities and ecosystems.
Open Access
Intraspecific variation in a predator affects community structure and cascading trophic interactions.
(Ecology, 2008-07) Post, DM; Palkovacs, EP; Schielke, EG; Dodson, SI
Intraspecific phenotypic variation in ecologically important traits is widespread and important for evolutionary processes, but its effects on community and ecosystem processes are poorly understood. We use life history differences among populations of alewives, Alosa pseudoharengus, to test the effects of intraspecific phenotypic variation in a predator on pelagic zooplankton community structure and the strength of cascading trophic interactions. We focus on the effects of differences in (1) the duration of residence in fresh water (either seasonal or year-round) and (2) differences in foraging morphology, both of which may strongly influence interactions between alewives and their prey. We measured zooplankton community structure, algal biomass, and spring total phosphorus in lakes that contained landlocked, anadromous, or no alewives. Both the duration of residence and the intraspecific variation in foraging morphology strongly influenced zooplankton community structure. Lakes with landlocked alewives had small-bodied zooplankton year-round, and lakes with no alewives had large-bodied zooplankton year-round. In contrast, zooplankton communities in lakes with anadromous alewives cycled between large-bodied zooplankton in the winter and spring and small-bodied zooplankton in the summer. In summer, differences in feeding morphology of alewives caused zooplankton biomass to be lower and body size to be smaller in lakes with anadromous alewives than in lakes with landlocked alewives. Furthermore, intraspecific variation altered the strength of the trophic cascade caused by alewives. Our results demonstrate that intraspecific phenotypic variation of predators can regulate community structure and ecosystem processes by modifying the form and strength of complex trophic interactions.