Thesis (doctoral)-- Rijksuniversiteit te Utrecht, 1994. / Vita. Includes bibliographical references (p. 189-195).

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

This PhD by Publication traces through 13 of my publications on economic incentives for forest management and conservation in tropical countries (with a regional bias towards Latin America), including several papers focused on participatory forest management or community-based conservation. The papers show how my thinking has evolved from a focus on market and nonmarket incentives, to an increasing emphasis on governance and regulatory incentives in explaining stakeholder behaviour to the forest resource, as well as the equity impacts. They reveal that positive incentives and win-win (environmental and poverty reduction) outcomes will only emerge when the underlying market, policy and institutional failures are tackled. Because of their public good values, the survival of tropical forests is contingent on the actions of the international community and governments. Sustainable forestry, therefore, depends on a combination of domestic governance progress to control illegal logging and the rent-seeking powers of vested interest groups, global governance regulations which create markets for environmental services, secure property rights for resident stakeholders and extra-sectoral policies that moderate land use opportunity costs. The current main hope for tropical forests is 'avoided deforestation' since this will need to tackle the forest governance problems and underlying multi-sectoral drivers of deforestation if it is to be successful. It represents a balanced market (payments for ecosystem services) and supply-side (improved governance) response to what is essentially a 'public goods' management problem, but will need to overcome some major political economy challenges.

No description available.

Ten species of anoles at Bajo Calima within the Choco of Western Colombia separate into two principal microhabitat groups: forest species, and those inhabiting openings and edges. The ten anoles further separate according to ground and vegetation dwellers. There is a relation at Bajo Calima between the number of anole species and vegetational structural diversity. Anole diversity within a given macrohabitat is by perch microsite/microclimate heterogeneity. These are the two major ecological dimensions along which similarity is limited or resources are partitioned.

The processes that regulate nutrient access by forest trees exhibit substantial variability on both large and small spatial scales. Explicit study of this spatial variability promotes a better understanding of the structure and function of forests. While the importance of space in ecological processes is being increasingly appreciated, there are major gaps in our knowledge about how space influences plant nutrient supply, particularly within a forest stand. This dissertation consists of three chapters that examine the patterns, drivers, and implications of spatial variation in three main processes that make nutrients available to trees: throughfall nutrient deposition, soil nutrient mineralization, and root system development. In Chapter 1, I use data from a field experiment to examine the effect of fertilization on nutrient transfer from the canopy to the soil via throughfall and litterfall in a tropical rainforest. I demonstrate that at small spatial scales, canopy density controls the flux of nutrients in throughfall, while at large scales, soil fertility is an important control, especially for phosphorus. I also show throughfall can be as important as litterfall in the recycling of certain essential nutrients like potassium, and depending on soil fertility, phosphorus. In Chapter 2, I investigate the small scale spatial patterning in soil nitrogen, a nutrient that frequently limits tree growth, in a temperate forest. By quantifying the degree of spatial inequality and autocorrelation in two plots characterized by different dominant tree species, I show that soil extractable nitrogen pools and net nitrogen mineralization fluxes exhibit a high degree of spatial patterning at scales less than 5 meters, with a majority of nitrogen availability contained within hotspots comprising a small proportion of soil area. I also demonstrate that this spatial patterning affects seedling access to soil nitrogen, which has consequences for seedling growth and survival. Chapter 3 examines how tree species and tree size affect the spatial distributions of root systems in two temperate tree species and explores how differences in root spatial coverage could affect tree nutrient access. I find that the spatial distributions of tree root systems can exhibit dramatic differences between species, with a tradeoff between root spatial coverage and total root length. I also discover that the effect of root spatial coverage on soil nutrient access is highly dependent on the spatial patterning of the soil nutrient, such that tree access to patchy nutrients varies greatly based on tree location within the local soil environment, even for medium-size trees. Together, these chapters characterize important patterns and mechanisms of spatial variation in the processes that regulate tree nutrient access.

Forest elephant (Loxodonta africana cyclotis) sociality is relatively little-studied due to the difficulties of making direct observations in rainforests. In Central Africa elephants aggregate at large natural forest clearings known as bais, which have been postulated to offer social benefits in addition to nutritional resources. This thesis explores the role of these clearings as social arenas by examining bai use within three main themes; ecology, sociality and risk factors. Seasonal changes in elephant use of the Maya Nord bai (Republic of Congo) are described, along with the demography of the visiting population. Elephant visit rate was highly variable; the number of elephants using Maya Nord in an observation day ranged from 0 to 117 animals. This variability was unrelated to local resource availability and productivity suggesting that bai use occurs year round. Elephants in Odzala-Kokoua do not show high fidelity to a single clearing; 454 elephants were individually identified and re-sighted an average of 1.76 times (range 1-10) during the twelve month study period. Previous bai studies have yet to quantify how elephants associate with one another within the bai area. This study examines socio-spatial organisation and associate choice using two measures of association within the 0.23 km2 bai area; aggregations (all elephants present in the clearing) and parties (elephants spatially co-ordinated in activity and movement) and distinguishes these from parties that range together (i.e. arrive and leave together). Social network analyses (SocProg) were used to describe inter- and intra-sexual multi-level organisation in the bai environment, and to illustrate the non-random nature of elephant aggregations and parties. Bais were shown to function as social arenas; female elephants showed active choice of certain associates and active avoidance of others when creating parties, whereas males were less discriminatory. Parties formed in the clearing (mean size= 3.93, SE= 0.186) were larger than ranging parties (mean size= 2.71, SE= 0.084) and elephants stayed for 50% longer in the clearing when they associated with individuals from outside their ranging party. Inter- and intra-sexual relationships were maintained within the clearing, and these are suggested to offer elephants essential opportunities for social learning. The patterning and nature of the relationships observed at the Maya Nord clearing indicates that forest elephants use a fission-fusion social structure similar to that of savannah elephants (Loxodonta africana africana); relationships are significantly structured by age- and sex- and underpinned by individual identity. Old experienced females hold key roles for forest elephants, and male relationships are superimposed on the network of female associations. Odzala-Kokoua elephants use bais to maintain their social relationships despite being highly sensitive to the anthropogenic risks involved in using these open areas. The results of this study suggest that forest and savannah elephants lie on the same social continuum, balancing social “pulls” to aggregate against the ecological “pushes” that force groups to fission. Previous models of savannah elephant sociality construct levels of association and social complexity upwards from the basic mother-calf unit (e.g. Wittemyer & Getz 2007). My results suggest that it may be more appropriate to consider elephant sociality and associations as in dynamic equilibrium between social and ecological influences acting at all levels of grouping, and to explicitly test how these underlie the opportunity costs that elephants are willing to pay in order to maintain social groupings.

Studies were carried out in a lowland evergreen rain forest (LERF), on an ultisol, in the 'Reserva da Campina', 45 km north of Manaus, and in two facies of the highly distinct formation called heath forest, on spodosols. The spodosols had a layer of mor humus of thickness varying from nil in some parts in the smaller facies of heath forest (SHF) to 35 cm in the taller facies (THF). The overall aim was to investigate the forest soil biota and its role in nutrient turnover by comparing the SHF, THF and LERF. Microbial biomass, soil respiration and nitrogen transformation rates were measured in the three forest types in both wet and dry seasons. Field and laboratory fertilization experiments were made to investigate potential limiting nutrients for microorganisms and plants. The role of fine roots in decomposition and litter animal colonization was assessed in litter bag studies. SHF soils have a small microbial population with no net nitrification in any season. THF soils showed a variable microbial population adapted to high acidity, which immobilises nitrogen during the wet season, but which allows a net release during the dry season. LERF showed the most diverse population which causes mineralization and nitrification in both seasons. A bioassay with nutrient addition showed that the low pH, and nitrogen and sulphur supply were likely to be limiting nitrogen dynamics in all forest types, but especially in THF and LERF. The ingrowth bags showed that despite the lower values of fine root growth in the SHF (particularly when the white sand of the spodosol was used as the substrate), the roots showed in all plots an increased production with added calcium as carbonate or sulphate. In the decomposition bioassay to evaluate the role of roots in the nutrient turnover it was shown that in all forest types there was no effect of roots on the mass loss of Clitoria leaves but there was a significant effect on concentrations of some nutrients. In general, roots contributed to the accumulation of aluminium and iron and to a faster release and uptake of calcium, magnesium and zinc. A survey of the mycorrhizal associations in all forest types showed that both VAM and ECM fungi with some unknown VAM fungal species are common. VAM and ECM adaptation to low pH and high phenolic compounds in the soils may be important in the maintenance of these ecosystems.

Thesis (doctoral)--Universiteit Utrecht, 1995. / Vita. Includes bibliographical references (p. 89-94).

In this thesis, the biogeography of the centipede family Scolopendridae of the Western Ghats (WG)was studied. First, a novel limited sampling approach to identify putative Gondwanan origin wherein sampling of was confined to one of the Gondwanan fragments, i.e. the WG was developed. The results indicated that at least four genera, Scolopendra, Cormocephalus, Rhysida and Digitipes of Scolopendridae, have diversified on the drifting peninsular Indian plate, and thus might have a Gondwanan origin. Three of these genera, Cormocephalus, Scolopendra and Rhysida, might have dispersed out of India and Digitipes has remained a Gondwanan relict. Second, an integrative frame work was used to delimit species boundaries in the genus Digitipes which was characterized as an ancient, endemic and monophyletic group. A new phylogenetic hypothesis was proposed for the genus Digitipes, with eight sampled species of which three were described and five were potentially new species. Among the five potentially un-described species, three were morphologically cryptic, emphasizing the effectiveness of this approach in revealing cryptic diversity. Third, historical biogeography of wet evergreen species of WG was evaluated using the genus Digitipes from the WG. Biogeographic and divergence date estimation suggest that the southern WG was indeed a refuge for Digitipes species of the WG during Cretaceous volcanism. The dated molecular phylogeny of family Scolopendridae as well as of genus Digitipes obtained in the current study will be useful in future comparative biogeography and diversification studies in the WG.