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Niche structure, dynamics, and coexistence in natural microcosms

Titel Englisch Niche structure, dynamics, and coexistence in natural microcosms
Gesuchsteller/in Bersier Louis-Félix
Nummer 165800
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Unité d'Ecologie et Evolution Département de Biologie Université de Fribourg
Hochschule Universität Freiburg - FR
Hauptdisziplin Oekologie
Beginn/Ende 01.12.2016 - 30.11.2019
Bewilligter Betrag 430'500.00
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Keywords (8)

community ecology; food web; Sarracenia purpurea; theoretical ecology; niche theory; biodiversity; modelling; global warming

Lay Summary (Französisch)

Lead
Structure de la niche, dynamique et coexistence dans des systèmes microbiens naturels
Lay summary

L'étude de la dynamique des communautés naturelles est une question fondamentale en écologie. Elle a des portées sociétales importantes car les écosystèmes fournissent de nombreux services, par exemple la régulation et l'épuration des eaux ou la production de ressources alimentaires ou pharmacologiques. Ainsi, il n'est pas étonnant que les écologistes se soient attelé à l'exploration des facteurs gouvernant le fonctionnement et la dynamique des systèmes naturels. Cette question est difficile et les chercheurs ont souvent utilisé la modélisation par simulation numérique. Toutefois, les conclusions tirées de telles approches dépendent généralement du choix des valeurs des paramètres des modèles. Le but de ce projet est de combiner modélisation mécanistique et approche expérimentale pour étudier en détail la dynamique de systèmes naturels simples. Nous allons utiliser les communautés aquatiques vivant dans les feuilles en forme d'urne de la Sarracénie pourpre. En Suisse, ces communautés comprennent des bactéries qui sont consommées par des protistes, formant ainsi un système à deux niveaux trophiques. Il est possible de manipuler la composition de ces systèmes, de les soumettre à des régimes différents de températures, et de suivre précisément leur changement dans le temps. Nous allons conduire une série d'expérience pour comprendre comment l'adaptation des protistes à leur niche alimentaire permet leur coexistence, et comment la température module ces processus.  

Direktlink auf Lay Summary Letzte Aktualisierung: 13.12.2016

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Verbundene Projekte

Nummer Titel Start Förderungsinstrument
138489 The organisation of ecological networks in time and space 01.01.2012 Projektförderung (Abt. I-III)
147630 Testing the limits and constraints of species radiations 01.06.2014 Sinergia

Abstract

The study of community dynamics is a fundamental domain of theoretical ecology, and its importance is becoming more acute given current global change. After the seminal work of May (1973), a large body of research has explored this question. Different aspects have been explored, from the consequence of adaptive dynamics to the distribution of body size among trophic levels. Most of these studies have identified features of communities that lead to stability. However, these works have mostly relied on simulation studies, which was recently shown to be highly sensitive to the parameterization of the models (Rohr et al. 2014). Here, we aim to explore the question of dynamics and coexistence in communities by studying in detail the mechanisms of niche adaptation along gradients of biodiversity. This will be achieved by using the natural communities of the pitcher plant Sarracenia purpurea, which are mainly composed of bacteria and protozoans, forming simple, two trophic-levels systems. The decisive advantage is the possibility of conducting replicated experiments in incubators, which will allow the precise description of the fundamental and realized trophic niche of the protozoans, and the following of the dynamics of the resource and the consumers. The project is organized in a series of five theory- and model-driven experiments. First, we will describe the fundamental trophic niche of chosen protozoans sampled from different sites. This will require the measurements of the interaction strength for a continuous axis of resource, which in our case is the size spectrum of bacteria. Second, we will explore the realized niche of these protozoans with increasing numbers of competitors. This will allow us to study how average interaction strength scales with species richness, which is fundamental to understand species coexistence. Third, we will examine how these results are affected by changes in temperature. Fourth, we will manipulate the structure of the protozoan communities to obtain a gradient of species richness and of average interaction strength, in order to test general predictions of niche theory. Finally, we will explore how increasing temperature affects coexistence in these manipulated communities. The experiments will be complemented by a modelling part investigating the dynamics of consumer-resource systems where resources span a continuous range, and by two reviews and syntheses on the different notions of stability and on the works exploring the “devious strategies” that favour species coexistence.The present project is interdisciplinary, linking ecologists and mathematicians. We expect that the results will attract much attention, as they will explore predator-prey dynamics mechanistically. This will allow a precise assessment of the factors underlying species coexistence, as well as the possibility to provide predictions for the effects of climate change on the dynamics of natural communities.
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