Abstract
Neglecting the naturally existing functional diversity of communities and the resulting potential to respond to altered conditions may strongly reduce the realism and predictive power of ecological models. We therefore propose and study a predator-prey model that describes mutual feedback via species shifts in both predator and prey, using a dynamic trait approach. Species compositions of the two trophic levels were described by mean functional traits—prey edibility and predator food-selectivity—and functional diversities by the variances. Altered edibility triggered shifts in food-selectivity so that consumers continuously respond to the present prey composition, and vice versa. This trait-mediated feedback mechanism resulted in a complex dynamic behavior with ongoing oscillations in the mean trait values, reflecting continuous reorganization of the trophic levels. The feedback was only possible if sufficient functional diversity was present in both trophic levels. Functional diversity was internally maintained on the prey level as no niche existed in our system, which was ideal under any composition of the predator level due to the trade-offs between edibility, growth and carrying capacity. The predators were only subject to one trade-off between food-selectivity and grazing ability and in the absence of immigration, one predator type became abundant, i.e., functional diversity declined to zero. In the lack of functional diversity the system showed the same dynamics as conventional models of predator-prey interactions ignoring the potential for shifts in species composition. This way, our study identified the crucial role of trade-offs and their shape in physiological and ecological traits for preserving diversity.
Highlights
One of the outstanding features of life on Earth is the tremendous diversity encountered at almost all hierarchical scales
We investigate i) how the potential of trait variation at no, one or two trophic levels influences the dynamical behavior of a two-trophic-level system and ii) the internal mechanisms that maintain functional diversity and the potential of trait variation
We held the mean trait values constant (i), we allowed for trait variation within one trophic level by dynamic simulation of either the prey edibility Q (ii) or the predator food-selectivity v (iii), and we allowed for trait variation within both trophic levels, i.e., dynamic simulation of Q and v (iv)
Summary
One of the outstanding features of life on Earth is the tremendous diversity encountered at almost all hierarchical scales (e.g., at the level of functional types, species, clones and genotypes). This diversity enables ecological systems to adapt to the prevailing conditions which often buffers their responses to perturbations. Neither populations nor communities function like a mechanic watch where a change in one gearwheel is immediately, proportionally and directly transmitted to the subsequent ones Rather, their inherent diversity enables compositional changes at lower hierarchical levels that may buffer the response at the higher hierarchical level [1,2,3]. This raises the question of how diversity and functional diversity in particular influences the mutual interplay between adjacent trophic levels or among a suite of competitors, and how this feeds back to the maintenance of diversity itself
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
