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Publié par | technischen_universitat_darmstadt |
Publié le | 01 janvier 2010 |
Nombre de lectures | 53 |
Poids de l'ouvrage | 55 Mo |
Extrait
Functional Response of Terrestrial Predators
Vom Fachbereich Biologie der Technischen Universität Darmstadt
zur
Erlangung des akademischen Grades
eines Doctor rerum naturalium
genehmigte Dissertation von
Dipl.-Biol. Olivera Vucic-Pestic
aus Frankfurt
Berichterstatter (1. Referent): PD Dr. habil. Ulrich Brose
Mitberichterstatter (2. Referent): Prof. Dr. Stefan Scheu
Tag der Einreichung: 19. Januar 2010
Tag der mündlichen Prüfung: 19. März 20102За моју фамuлuју
(Für meine Familie)
3Table of Contents
1.Overview..................................................................................................................................5
1.1.Background ......................................................................................................................5
1.2.What are food webs? ........................................................................................................6
1.3.Food web models .............................................................................................................7
1.4.Factors affecting interactions ...........................................................................................8
1.5.The metabolic theory .....................................................................................................10
1.6.Optimal foraging theory ................................................................................................11
1.7.Considerations about predatorprey body mass ratio .....................................................12
1.8.Generalist predators .......................................................................................................12
1.9.Functional response models ...........................................................................................13
1.10. Summary of investigations on functional responses ..................................................17
1.11. Studies in this thesis ....................................................................................................19
1.12.Outline of the thesis ....................................................................................................20
1.13.Conclusions ..................................................................................................................21
1.14.Contributions to the included articles ..........................................................................22
2.Articles...................................................................................................................................24
2.1.Foraging theory predicts predator–prey energy fluxes ..................................................24
2.2.Allometric functional response model: body masses constrain interaction strengths ...35
2.3.Temperature, predatorprey interaction strength and population stability .....................47
2.4.Prey mobility constrains warming effects on interaction strengths ...............................66
2.5.Habitat structure and prey aggregation determine the functional response in a soil
predatorprey interaction .......................................................................................................78
3.Bibliography...........................................................................................................................89
4.Appendix..............................................................................................................................112
4.1.Curriculum vitae ..........................................................................................................112
4.2.Eidesstattliche Erkl ärung.............................................................................................113
4.3.Danksagungen...........114
4Niemand bestreitet die Wunder der modernen Wissenschaft. Jetzt
wäre es an der Zeit, dass sie auch f ür ihre Monster die Verantwortung
übernimmt.
Jakob von Üxküll (18641944) dt.schwed. Biologe und Begr ünder der Umweltforschung
51. Overview
1.1. Background
Human activity has a profound impact on almost all terrestrial ecosystems of. Climate change
is predicted to alter dramatically the temperature and precipitation patterns at all latitudes, and
anthropogenic impacts such as pollution or poor ecosystem management result in widespread
perturbations of native ecosystems. In order to minimise the impact of anthropogenic
perturbations on ecosystem stability and function, it is of crucial importance to understand
how perturbations or in a broad sense long lasting biotic and abiotic changes influence the
structure of natural communities and which parameters are pivotal for preventing a collapse of
the system.
The structure of natural communities is mainly determined by predatorprey interactions. The
different predators and preys are linked in these communities via trophic interactions, and the
outcome of these trophic interactions are a major determinant of the populationdynamics of
the cooccurring species, and thus of their contribution to ecosystem function. Predator and
prey populations are rarely at an equilibrium state, and natural communities are subject to
important fluctuations of predator and prey populations. These fluctuations are caused by
both, abiotic factors such as seasonal weather conditions, and direct consequences of trophic
consumerresource interactions. In most cases, despite these fluctuations, the populations can
persist locally for long time periods. However, fluctuating populations can result in an
increased instability of the community and even in extinction events, with, in some cases,
dramatic consequences for the stability of the whole system.
One aspect of this work was to investigate how habitat destruction and climate change may
affect predatorprey interactions and consequently the community structure in terrestrial
ecosystems. Various abiotic and biotic factors determine the predatorprey relationship in
terrestrial ecosystems, and the interaction strength between a predator and its prey depends
mainly on the prey abundance and on the predators efficiency of resource acquisition. Thus,
we investigated the impact of habitat structure on this interaction. Structured habitat can
reduce the predation pressure by reducing the encounter rate between predator and prey, and
by providing refuge space accessible for the prey but not for the predator. The metabolic rates
of invertebrates increase with temperature, and raising global temperatures may not only lead
to changes in the habitat structure, but also affect the predatorprey relationship by modifying
the energetic requirements of both species. In order to understand and predict the effect of
global warming on complex communities,