Diversity and Ecology of Spider Assemblages in Secondary Forests of the Southern Mata Atlântica, Brazil Implications for Environmental Conservation
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Diversity and ecology of spider assemblages in secondary forests of the southern Mata Atlântica, Brazil Implications for environmental conservation Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. nat.) des Fachbereichs Biologie der Philipps-Universität Marburg vorgelegt von Dipl.-Biol. Florian Raub aus Malsch bei Karlsruhe Marburg (Lahn), 2015 Vom Fachbereich Biologie der Philipps-Universität Marburg als Dissertation angenommen am 12.02.2016 Erstgutachter: Prof. Dr. Roland Brandl Zweitgutachter: Dr. Hubert Höfer Tag der Disputation: 17.02.2016 Erklärung Ich versichere, dass ich meine Dissertation „Diversity and ecology of spider assemblages in secondary forests of the southern Mata Atlântica, Brazil – Implications for environmental conservation” selbständig und ohne unerlaubte Hilfe angefertigt habe und mich keiner als der von mir ausdrücklich bezeichneten Quellen und Hilfen bedient habe. Diese Dissertation wurde in der jetzigen oder ähnlichen Form noch bei keiner anderen Hochschule eingereicht und hat noch keinen sonstigen Prüfungszwecken gedient. Marburg (Lahn), 2015 Inhalt 1 – Introduction .................................................................................................................................... 1 Biodiversity and its function in tropical forests .................................................................................. 1 The SOLOBIOMA project and spider study ....................................................................................... 2 Diversity and ecology of spiders – their use as indicators .................................................................. 4 Study areas .......................................................................................................................................... 5 Outline of this dissertation .................................................................................................................. 6 References ........................................................................................................................................... 7 2 – The conservation value of secondary forests in the southern Brazilian Mata Atlântica from a spider perspective. .................................................................................................................... 14 Abstract ............................................................................................................................................. 14 Introduction ....................................................................................................................................... 14 Material and Methods ........................................................................................................................ 16 Results ............................................................................................................................................... 20 Discussion ......................................................................................................................................... 34 References ......................................................................................................................................... 38 3 – Conserving landscape structure – conclusions from the partitioning of spider diversity in southern Atlantic forests of Brazil. ............................................................................................ 46 Abstract ............................................................................................................................................. 46 Introduction ....................................................................................................................................... 46 Materials and Methods ...................................................................................................................... 50 Results ............................................................................................................................................... 54 Discussion ......................................................................................................................................... 62 References ......................................................................................................................................... 67 4 – No bottom-up effects of food limitation on predators in a tropical forest. ............................. 73 Abstract ............................................................................................................................................. 73 Introduction ....................................................................................................................................... 73 Materials and Methods ...................................................................................................................... 75 Results ............................................................................................................................................... 77 Discussion ......................................................................................................................................... 82 References ......................................................................................................................................... 84 5 – Outlook ......................................................................................................................................... 88 6 – Summary ...................................................................................................................................... 89 7 – Zusammenfassung ....................................................................................................................... 91 8 – Appendix ....................................................................................................................................... 94 Supporting Materials Chapter 2......................................................................................................... 94 Supporting Materials Chapter 3....................................................................................................... 110 Supporting Materials Chapter 4....................................................................................................... 111 Curriculum Vitae ............................................................................................................................. 116 Publications ..................................................................................................................................... 117 Danksagung/Acknowledgements .................................................................................................... 118 Abgrenzung der Eigenleistung ........................................................................................................ 119 1 – Introduction Biodiversity and its function in tropical forests Tropical forests are among the most species rich ecosystems on earth (Bradshaw et al., 2009; Gibson et al., 2011; Pimm & Raven, 2000; Wilson, 1992) and they have therefore repeatedly been in the focus of science. First, during the era of biodiversity inventories to answer the question of how many species may exist on earth (Stork, 1993), later, when the studies on the function (or redundancy) of species richness (Loreau et al., 2001) gained more attention. Finally, the ecosystem services linked to species richness and the threat to loose many of them due to the ongoing loss of species (Rey Benayas et al., 2009) became a key aspect of studies of (tropical) ecology. For a long time vertebrate species have attracted the main attention of scientists and conservation managers and were used to provide arguments to preserve diversity. Recently more research effort has been put into the analysis of arthropod communities, of their function, and of the impact of land use on their diversity and distribution (Barlow et al., 2007; Lawton et al., 1998). Numerous globally important ecosystem services are offered or at least strongly influenced by arthropods, e.g. biocontrol or decomposition (Feld et al., 2009; Nelson et al., 2009). So these organisms sustain also the proper function of tropical forest ecosystems, which cover 7% of the land area of our planet but host two-thirds of the terrestrial diversity (Raven, 1980; Wilson, 1992). The fertility of tropical soils and therewith the basis for the maintenance and use of tropical forest ecosystems relies on the recycling of nutrients during the decomposition of leaf and wood litter and the stock of organic matter in the soil. The deeply weathered soils cannot provide nutrients from deeper layers (Vitousek & Sanford, 1986) as in most temperate ecosystems. Soil arthropods initiate the remobilization of nutrients fixed in the litter (Martius et al., 2004a; Schmidt et al., 2008; Wardle, 1999). They foster the generation of organo- mineral structures and therewith the nutrient availability for plants (Brussaard & Juma, 1996; Rossi et al., 2010). As “ecosystem engineers” some arthropods can also visibly form ecosystems. Their presence is overall crucial for ecosystems persistence (Giller & O´Donovan, 2002; Milton & Kaspari, 2007): Via direct and indirect interactions in the food web dynamics they help to maintain the sensitive nutrition balance of tropical forest ecosystems (Abrams et al., 1996). Nowadays it is well known that a disturbance of the ecological