Trophic interactions of ants, birds and bats affecting crop yield along shade gradients in tropical agroforestry

Gras, Pierre

dc.contributor.advisor	Tscharntke, Teja Prof. Dr.
dc.contributor.author	Gras, Pierre
dc.date.accessioned	2015-12-09T09:33:06Z
dc.date.available	2015-12-09T09:33:06Z
dc.date.issued	2015-12-09
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-0028-8666-7
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-5390
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-5390
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-5390
dc.language.iso	eng	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	570	de
dc.title	Trophic interactions of ants, birds and bats affecting crop yield along shade gradients in tropical agroforestry	de
dc.type	doctoralThesis	de
dc.contributor.referee	Vidal, Stefan Prof. Dr.
dc.date.examination	2014-12-10
dc.description.abstracteng	Tropical agroforests are diverse systems where several predator groups shape animal communities and plant-arthropod interactions. Ants, birds and bats in particular can reduce herbivores and thereby increase crop yield. However, the relative importance of these groups, whether they interact, and how this is affected by management and landscape context, is poorly understood. We jointly manipulated access of ants, birds and bats in Indonesian smallholder cacao agroforestry across gradients of shade and distance to natural forest. We quantified arthropod abundance, pest damage and yield. The trophic web within ant communities was investigated by analyzing stable nitrogen and carbon isotopes. Thereby, we examined how trophic positions of ants respond to plant phenology, shade cover and distance to forest margins. Our results suggest: (1) The Impact of ants and birds on cacao yield is economically relevant, and depends on shade-tree management. (2) Intraspecific diets of ants are conditional to plant phenology and help to distinguish species-specific ecosystem services and disservices. (3) Both, trophic plasticity and species turnover are mechanisms defining ecological functions of omnivore communities. (4) Diet shifts are conditional to co-occurring, competing species.	de
dc.contributor.coReferee	Clough, Yann Dr.
dc.contributor.thirdReferee	Scherber, Christoph Dr.
dc.contributor.thirdReferee	Wiegand, Kerstin Prof. Dr.
dc.contributor.thirdReferee	Maraun, Mark PD Dr.
dc.subject.eng	ant	de
dc.subject.eng	bird	de
dc.subject.eng	bat	de
dc.subject.eng	shade	de
dc.subject.eng	forest distance	de
dc.subject.eng	biological control	de
dc.subject.eng	Theobroma cacao	de
dc.subject.eng	trophic interactions	de
dc.subject.eng	yield	de
dc.subject.eng	ecosystem service	de
dc.subject.eng	predation	de
dc.subject.eng	omnivores	de
dc.subject.eng	stable isotope	de
dc.subject.eng	food web	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-0028-8666-7-7
dc.affiliation.institute	Biologische Fakultät für Biologie und Psychologie	de
dc.subject.gokfull	Biologie (PPN619462639)	de
dc.identifier.ppn	843242345

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