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ERC

ECOSTRESS Report Summary

Project ID: 337023
Funded under: FP7-IDEAS-ERC
Country: Israel

Mid-Term Report Summary - ECOSTRESS (Physiological Reaction to Predation- A General Way to Link Individuals to Ecosystems)

Ecological science has largely treated the study of the organismal and biogeochemical aspects of ecosystems as separate scientific enterprises, in spite of the emerging recognition that species interactions in food-webs may determine the nature of elemental flux and cycling. In recent years, there has been a growing research effort to bridge this conceptual gap by developing ways to scale processes at the individual levels to higher levels of biological organization. The ERC-funded ECOSTRESS project contributes to this emerging effort by developing and experimentally testing an altogether new theory that links plasticity in prey responses to predation and biogeochemical processes so as to explain context-dependent variations in ecosystem functioning.

Animals in food-webs regulate ecosystem processes by controlling the transfer of nutrients from plants to higher levels in the food, and through top-down control over the identity, abundances and functional traits of species lower down in the food-web. However, this regulatory role is not a constant feature of a species. Prey species regularly tweak expressions of behavioral, physiological, morphological, and life history traits in attempt to lessen elevated risk of predation. The ECOSTRESS framework makes use of new advances in nutritional ecology to predict how these defensive phenotypes may alter animals' nutritional requirements or constrain their ability to achieve those requirements. This understanding enables to predict changes in prey diet and nutritional composition of their waste material and body composition. Such changes in-turn may modify the soil food-web function, hence ecosystem functioning by (a) regulating the quantity and nutritional quality of plants and animal production known to drive the SFW, (b) inducing defense phenotypes in soil-organisms, and (c) changing soil environmental conditions (see Hawlena and Zguri 2016, SBB).

The ECOSTRESS project uses a combination of manipulative field experiments, highly controlled laboratory and garden experiments, and state of the art stable isotopes' approaches to systematically test this novel framework across species and ecosystems. First empirical examination of the theory offers very promising insights. All species examined (snails, isopods, grasshoppers and lizards) presented defensive phenotypes. Yet, for isopods the framework failed to predict dietary changes based solely on macro-nutrients. This finding calls for expansion of the theory to include micro-nutrient, because field observations did show predator induced diet shift. Moreover, exploration of the interface between different categories of inducible defenses revealed that their integrative effect on prey diet choice is context dependent. Environmental and evolutionary constraints on prey foraging behavior may alter the defensive strategy, altering the prey diet choice. Exploration of potential pathways by which inducible defenses may alter ecosystem processes revealed that nutritional quality of small detrital inputs had a strong legacy effect on the microbial community function. The effect held even after a long time period (7 months) that included two consecutive additions of large quantities of low quality plant litter. These insights may emphasize the framework potential to explain variation in ecosystem functioning using changes in food-web dynamics. This potential will be specifically tested during the second stage of the ECOSTRESS project.

Contact

Hani Ben Yehuda
Tel.: +972 2 6586676
Fax: +972 2 722447007
E-mail
Record Number: 191498 / Last updated on: 2016-11-21
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