Interactive effects of climate and nutrient enrichment on patterns of herbivory by different feeding guilds in mangrove forests

Warming has profound effects on biological rates such as metabolism, growth, feeding and death of organisms, eventually affecting their ability to survive. Using a nonlinear bioenergetic population-dynamic model that accounts for temperature and body-mass dependencies of biological rates, we analysed the individual and interactive effects of increasing temperature and nutrient enrichment on the dynamics of a three-species food chain. At low temperatures, warming counteracts the destabilizing effects of enrichment by both bottom-up (via the carrying capacity) and top-down (via biological rates) mechanisms. Together with increasing consumer body masses, warming increases the system tolerance to fertilization. Simultaneously, warming increases the risk of starvation for large species in low-fertility systems. This effect can be counteracted by increased fertilization. In combination, therefore, two main drivers of global change and biodiversity loss can have positive and negative effects on food chain stability. Our model incorporates the most recent empirical data and may thus be used as the basis for more complex forecasting models incorporating food-web structure.

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Multiple stressors and disturbance effects on eelgrass and epifaunal macroinvertebrate assemblage structure

Marine Ecology Progress Series ◽

10.3354/meps13546 ◽

2021 ◽

Vol 657 ◽

pp. 93-108

Author(s):

S Cimon ◽

A Deslauriers ◽

M Cusson

Keyword(s):

Nutrient Enrichment ◽

Field Experiments ◽

Multiple Stressors ◽

Shoot Density ◽

Assemblage Structure ◽

Interactive Effects ◽

Anthropogenic Pressure ◽

Ecosystem Structure ◽

Density Reduction ◽

External Forces

Multiple forms of environmental change and anthropogenic pressure co-occur in coastal marine ecosystems. These external forces affect ecosystem structure, functioning, and, eventually, services to humans. Studies that include more than 2 simultaneous stressors are still needed to understand potential interactions among multiple stressors. We evaluated single and interactive effects of density reduction of Zostera marina L. (a habitat-forming species), shading, and sediment nutrient enrichment on the response of Z. marina and its associated epifauna over 10 wk. Shading had the greatest effect on reducing the eelgrass relative leaf elongation rate (RLE), non-structural carbohydrate reserves, and eelgrass shoot density. A reduced eelgrass density sustained higher epifaunal densities and increased the eelgrass RLE. Sediment nutrient enrichment increased eelgrass shoot density but decreased epifaunal richness, diversity, and total abundance. Our disturbance and pair of stressors differed in their influence on diversity measures, but all affected assemblage structure. Most of the changes to the epifaunal assemblage and diversity likely occurred due to altered habitat availability and epiphytic algae load. We observed additive, antagonistic, and negatively synergistic interactions among our treatments, while most of the cumulative effects showed dominance by one stressor over another. Our results highlight the importance of field experiments that are based on multiple disturbances and stressors to determine their interaction type on communities.

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Climate modifies response of non-native and native species richness to nutrient enrichment

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2015.0273 ◽

2016 ◽

Vol 371 (1694) ◽

pp. 20150273 ◽

Cited By ~ 19

Author(s):

Habacuc Flores-Moreno ◽

Peter B. Reich ◽

Eric M. Lind ◽

Lauren L. Sullivan ◽

Eric W. Seabloom ◽

...

Keyword(s):

Species Richness ◽

Nutrient Enrichment ◽

Time Scale ◽

Native Species ◽

Niche Partitioning ◽

Climatic Conditions ◽

Nutrient Addition ◽

Interactive Effects ◽

Native Plant ◽

Native Species Richness

Ecosystem eutrophication often increases domination by non-natives and causes displacement of native taxa. However, variation in environmental conditions may affect the outcome of interactions between native and non-native taxa in environments where nutrient supply is elevated. We examined the interactive effects of eutrophication, climate variability and climate average conditions on the success of native and non-native plant species using experimental nutrient manipulations replicated at 32 grassland sites on four continents. We hypothesized that effects of nutrient addition would be greatest where climate was stable and benign, owing to reduced niche partitioning. We found that the abundance of non-native species increased with nutrient addition independent of climate; however, nutrient addition increased non-native species richness and decreased native species richness, with these effects dampened in warmer or wetter sites. Eutrophication also altered the time scale in which grassland invasion responded to climate, decreasing the importance of long-term climate and increasing that of annual climate. Thus, climatic conditions mediate the responses of native and non-native flora to nutrient enrichment. Our results suggest that the negative effect of nutrient addition on native abundance is decoupled from its effect on richness, and reduces the time scale of the links between climate and compositional change.

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