Birds, bats and arthropods in tropical agroforestry landscapes: Functional diversity, multitrophic interactions and crop yield

Maas, Bea

dc.contributor.advisor	Tscharntke, Teja Prof. Dr.
dc.contributor.author	Maas, Bea
dc.date.accessioned	2014-04-03T08:31:35Z
dc.date.available	2014-04-03T08:31:35Z
dc.date.issued	2014-04-03
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-0022-5E77-5
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-4441
dc.language.iso	eng	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/
dc.subject.ddc	630	de
dc.title	Birds, bats and arthropods in tropical agroforestry landscapes: Functional diversity, multitrophic interactions and crop yield	de
dc.type	doctoralThesis	de
dc.contributor.referee	Tscharntke, Teja Prof. Dr.
dc.date.examination	2013-11-20
dc.description.abstracteng	Ecosystem services such as the suppression of pest insects may increase productivity of agroforestry systems and thereby increase well-being of smallholders. Tropical birds and bats are effective predators of arthropods and move within landscapes, representing mobile links that connect habitats in space and time. But information on the effects of birds and bats on multitrophic interactions and agricultural productivity in different types of agroforestry systems is limited. Similarly, the relative importance of local agroforestry management and the tropical landscape matrix for ecosystem services mediated by birds has not been investigated so far. Last but not least, a better understanding of dynamic tropical agroforestry landscapes and the effects of habitat conversion and land use intensification on important functional groups as well as for endangered species is urgently needed. We conducted a predator exclusion experiment in which we manipulated the access of birds and bats on 15 different cacao agroforestry sites to quantify their effects on diurnal and nocturnal insects and spiders, cacao fruit development, leaf herbivory and the final crop yield over a period of 15 months. The selected cacao agroforestry sites were located on the island of Sulawesi (Indonesia) and differed in local management and distance to forest. The absence of birds and bats led to an increased density of insect herbivores and caused a concurrent release of mesopredators such as ants and spiders despite negative effects on the development of cacao fruits and a remarkable decrease of final cacao crop yield of 31 % across local and landscape gradients. In addition to bird and bat field exclusion experiments, we investigated the group of insectivorous birds with two different sampling methods. Using an arthropod predation experiment (standardized exposure of dummy caterpillars), we quantified predation rates in relation to the identity and diversity of insectivorous birds. We discovered that responses of the insectivorous bird community and the predation activity differed with the landscape context and both increased with forest proximity. Our findings show that ecosystem services can be driven by single species rather than by overall communities of certain functional groups. Therefore, the conservation of species diversity and ecosystem services does not necessarily rely on the same management strategies, although nearby forests appeared to be of great importance for both bird diversity and avian ecosystem services. The importance of forest proximity and large trees in agroforestry landscapes was also shown in a species specific study we conducted on a declining local population of the Indonesian endemic Grosbeak Starling in our study area. Although this species is well adapted to anthropogenic landscapes, it is also closely associated with large remnant forest trees that remain along forest margin areas and land use systems as nesting sites. The rapid conversion of the forest margin landscape in Central Sulawesi led to a sharp decline of such nesting sites by 92% within only two years. Hence, the endemic Grosbeak Starling is likely to be currently endangered although it was locally very abundant a few years ago. These results show how fast conversion of natural habitats and resource extraction in increasingly intensified tropical agroforestry landscapes can result in changes of the local species diversity. In conclusion, we demonstrate the importance of the quantification of final ecosystem services such as fruit productivity and crop yield to improve the valuation of ecosystem services provided by tropical birds and bats. Species diversity and species identity are both important measures for functional diversity and ecosystem functioning, although with different importance for conservation and the smallholders’ economics. A single common species (Zosterops chloris) was more important for the service of arthropod suppression than overall bird species diversity. Nevertheless, nearby forest habitats and extensively used agroforests (shaded and without use of pesticides or other chemical compounds) turned out to be important for both biodiversity and ecosystem services. Multitrophic interactions between birds, bats and other natural enemies (ants and spiders) of phytophagous insects are likely to jointly impact the productivity of agroforestry systems in complex ways and therefore need to be considered simultaneously at different temporal and spatial scales.	de
dc.contributor.coReferee	Vidal, Stefan Prof. Dr.
dc.contributor.thirdReferee	Wiegand, Kerstin Prof. Dr.
dc.subject.eng	birds	de
dc.subject.eng	bats	de
dc.subject.eng	arthropods	de
dc.subject.eng	multitrophic interactions	de
dc.subject.eng	agroforestry	de
dc.subject.eng	tropical landscape	de
dc.subject.eng	forest margin landscape	de
dc.subject.eng	functional diversity	de
dc.subject.eng	crop yield	de
dc.subject.eng	exclosure experiments	de
dc.subject.eng	experimental exclusion	de
dc.subject.eng	arthropod suppression	de
dc.subject.eng	avian predation	de
dc.subject.eng	ecosystem services	de
dc.subject.eng	mist netting	de
dc.subject.eng	point counts	de
dc.subject.eng	artificial plasticine caterpillar	de
dc.subject.eng	dummy experiment	de
dc.subject.eng	biological control	de
dc.subject.eng	monitoring	de
dc.subject.eng	mapping	de
dc.subject.eng	Lemon-bellied White-eye	de
dc.subject.eng	Grosbeak Starling	de
dc.subject.eng	Zosterops chloris	de
dc.subject.eng	Scissiostrum dubium	de
dc.subject.eng	Theobroma cacao	de
dc.subject.eng	cacao agroforestry	de
dc.subject.eng	cacao diseases	de
dc.subject.eng	cacao harvest	de
dc.subject.eng	cacao pests	de
dc.subject.eng	flying vertebrates	de
dc.subject.eng	aerial insectivores	de
dc.subject.eng	volant vertebrates	de
dc.subject.eng	logging	de
dc.subject.eng	breeding colony	de
dc.subject.eng	flower herbivory	de
dc.subject.eng	mesopredator release	de
dc.subject.eng	predatory insects	de
dc.subject.eng	ants	de
dc.subject.eng	spiders	de
dc.subject.eng	aphids	de
dc.subject.eng	Lepidoptera	de
dc.subject.eng	Coleoptera	de
dc.subject.eng	Lepidopteran larvae	de
dc.subject.eng	sustainable agriculture	de
dc.subject.eng	sustainable agroforestry	de
dc.subject.eng	management implications	de
dc.subject.eng	management recommendations	de
dc.subject.eng	applied managament	de
dc.subject.eng	extensive land use management	de
dc.subject.eng	landscape management	de
dc.subject.eng	conservation	de
dc.subject.eng	biodiversity-friendly	de
dc.subject.eng	dbh	de
dc.subject.eng	distance to forest	de
dc.subject.eng	forest proximity	de
dc.subject.eng	habitat conversion	de
dc.subject.eng	herbivory	de
dc.subject.eng	Indonesia	de
dc.subject.eng	insectivorous bats	de
dc.subject.eng	insectivorous birds	de
dc.subject.eng	invertebrates	de
dc.subject.eng	Central Sulawesi	de
dc.subject.eng	Napu valley	de
dc.subject.eng	leaf gleaning	de
dc.subject.eng	leaf herbivory	de
dc.subject.eng	pests insects	de
dc.subject.eng	phytophagous insects	de
dc.subject.eng	plant productivity	de
dc.subject.eng	remnant forest trees	de
dc.subject.eng	shade tree managament	de
dc.subject.eng	South-east Asia	de
dc.subject.eng	Paleotropics	de
dc.subject.eng	tropical landscape	de
dc.subject.eng	tree height	de
dc.subject.eng	landscape gradient	de
dc.subject.eng	local shade management	de
dc.subject.eng	Cacao Pod Borer	de
dc.subject.eng	Cherelle Wilt	de
dc.subject.eng	fruit abortion	de
dc.subject.eng	Helopeltis sulawesi	de
dc.subject.eng	deforestation	de
dc.subject.eng	habitat fragmentation	de
dc.subject.eng	land use intensification	de
dc.subject.eng	forest margin species	de
dc.subject.eng	critical decline	de
dc.subject.eng	predation experiment	de
dc.subject.eng	species-specific functions	de
dc.subject.eng	Southeast Asia	de
dc.subject.eng	biodiversity conservation	de
dc.subject.eng	mesopredators	de
dc.subject.eng	food security	de
dc.subject.eng	human welfare	de
dc.subject.eng	human well-being	de
dc.subject.eng	poverty alleviation	de
dc.subject.eng	poverty reduction	de
dc.subject.eng	smallholder cacao	de
dc.subject.eng	smallholder plantation	de
dc.subject.eng	cacao farmers	de
dc.subject.eng	sustainable cacao management	de
dc.subject.eng	landscape perspective	de
dc.subject.eng	landscape scale	de
dc.subject.eng	large scale field experiment	de
dc.subject.eng	long term field experiment	de
dc.subject.eng	human wellbeing	de
dc.subject.eng	economic importance	de
dc.subject.eng	economic value	de
dc.subject.eng	valuation ecosystem services	de
dc.subject.eng	landscape matrix	de
dc.subject.eng	yield quality	de
dc.subject.eng	yield quantity	de
dc.subject.eng	fruit productivity	de
dc.subject.eng	species identity	de
dc.subject.eng	species diversity	de
dc.subject.eng	species richness	de
dc.subject.eng	ecosystem functioning	de
dc.subject.eng	pesticide use	de
dc.subject.eng	chemical compounds	de
dc.subject.eng	complex food web	de
dc.subject.eng	tritrophic interactions	de
dc.subject.eng	wildlife-friendly	de
dc.subject.eng	rural livelihoods	de
dc.subject.eng	endangered bird species	de
dc.subject.eng	endangered bat species	de
dc.subject.eng	endemic	de
dc.subject.eng	endemic birds	de
dc.subject.eng	endemic bats	de
dc.subject.eng	beneficial impact	de
dc.subject.eng	IUCN	de
dc.subject.eng	Lore Lindu National Park	de
dc.subject.eng	bioindicator	de
dc.subject.eng	indicator species	de
dc.subject.eng	forest margin	de
dc.subject.eng	agricultural habitat	de
dc.subject.eng	agroforestry systems	de
dc.subject.eng	population density	de
dc.subject.eng	predation activity	de
dc.subject.eng	species activity	de
dc.subject.eng	cacao flower	de
dc.subject.eng	cacao pod	de
dc.subject.eng	Orthoptera	de
dc.subject.eng	linear mixed effect models	de
dc.subject.eng	Tukey Post Hoc Test	de
dc.subject.eng	AICc model selection	de
dc.subject.eng	generalized least squares	de
dc.subject.eng	restricted maximum likelihood	de
dc.subject.eng	model simplification	de
dc.subject.eng	species richness estimator	de
dc.subject.eng	species accumulation	de
dc.subject.eng	linear mixed-effects models	de
dc.subject.eng	Likelihood Ratio Test	de
dc.subject.eng	Maximum Likelihood	de
dc.subject.eng	nocturnal insects	de
dc.subject.eng	diurnal arthropods	de
dc.subject.eng	nocturnal arthropods	de
dc.subject.eng	diurnal insects	de
dc.subject.eng	landscape context	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-0022-5E77-5-1
dc.affiliation.institute	Fakultät für Agrarwissenschaften	de
dc.subject.gokfull	Land- und Forstwirtschaft (PPN621302791)	de
dc.identifier.ppn	782353096

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