Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 15 / 15

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Biodiversity and key ecosystem services in agroforestry coffee systems in the Brazilian Atlantic Rainforest Biome
    Souza, H.N. de - \ 2012
    Wageningen University. Promotor(en): Lijbert Brussaard; I.M. Cardoso, co-promotor(en): Mirjam Pulleman; Ron de Goede. - S.l. : s.n. - ISBN 9789461731098 - 156
    agroforestry - biodiversiteit - ecosysteemdiensten - coffea - duurzaamheid (sustainability) - agroforestrysystemen - tussenteelt - inheemse planten - regenbossen - brazilië - agroforestry - biodiversity - ecosystem services - coffea - sustainability - agroforestry systems - intercropping - native plants - rain forests - brazil

    The thesis reports the results of long-term experimentation (since 1993) of family farmers with agroforestry (AF) coffee systems in the Brazilian Atlantic Rainforest region, a highly fragmented and threatened biodiversity hotspot. The farmers used native trees from forest fragments during a transition from the predominant full sun-coffee (SC) production to more diversified agriculture. The aim of the research was to gain understanding of different agricultural management systems within the complex landscape matrix with respect to farmers’ capacity to diminish negative impacts on the environment, based on an ecosystem services approach.

    Participatory Rural Appraisal was used to obtain data from the family farmers. A method of systematization of their experiments created platforms for reflexion and development of agroforestry systems for farmers, technicians and researchers beyond only listing the negative and positive results. Long-term effects of coffee agroforestry (AF), full-sun coffee (SC) systems and surrounding reference forest fragments (RF) were assessed on: tree biodiversity, microclimate, soil quality, costs of labour and inputs and profitability. Selection of appropriate tree species was essential to the success of agroforestry. The main criteria for selecting tree species by farmers were: compatibility with coffee, amount of tree biomass produced, diversification of the production and the labour needed for tree management. The farmers used 85 tree species across the area, 28 of which belonged to the Leguminosae, a family of nitrogen-fixing plants. Most trees were either native to the biome, or exotic fruit trees. The diversification of production, especially with fruit trees, contributed to food security and to a low cost/benefit ratio of AF.

    Comparisons between reference forest fragments, agroforestry coffee and sun coffee revealed the potential of AF to conserve local tree biodiversity. Litter quality on-farm was functional in terms of soil erosion and fertility management. The canopy of the trees mitigated high temperature extremes: maximum temperature in SC systems (32oC) was 5.4 oC higher than in AF. Some soil quality parameters (total organic carbon, microbial carbon, soil respiration and potential nitrogen mineralization) showed higher values in RF than AF and SC, but no differences were observed between AF and SC.

    There was considerable diversity in the strategies and management of farmers for AF (including the choice of tree species), affecting the productivity and profitability. The total production value of AF was on average 43% higher than that of SC, largely due to other products than coffee. Both systems had an overall higher return of labour than the wage rate in the area.

    Continued participative work among scientists and stakeholders may help to increase the delivery of ecosystem services provided by family agriculture. Production systems based on ecosystem service delivery beyond just crop production have potential to reduce the need for external inputs and contribute to major local, regional and global objectives, such as food security, adaptation to climate change and conservation of biodiversity.

    The Liana assemblage of a Congolian rainforest : diversity, structure and dynamics
    Ewango Ekokinya, Corneille - \ 2010
    Wageningen University. Promotor(en): Frans Bongers; Marc Sosef; Lourens Poorter. - [S.l.] : s.n. - ISBN 9789085858133 - 161
    climbing plants - rain forests - species diversity - species richness - forest ecology - congo - forest structure - klimplanten - regenbossen - soortendiversiteit - soortenrijkdom - bosecologie - congo - bosstructuur
    Key words: Liana assemblage, species composition, community, dynamics, canopy openness, Manniophyton fulvum, functional traits, population density, pervasive change.

    This study analyzes the diversity, composition, and dynamics of the liana assemblage of the Ituri rain forest in northeastern DR Congo. I used data from two 10-ha plots of the Ituri Forest Dynamics Plots, in which all liana stems ≥2 cm diameter at breast height (dbh) were marked, mapped, measured and identified in 1994, 2001 and 2007. In addition, the plot topography and canopy structure were measured.

    Chapter 2 analyzes the liana assemblage (in terms of species richness, abundance and diversity), characterizes liana functional traits and determines effects of forest structure, topography and edaphic variation on liana species composition. In 20 ha, 15008 liana individuals were found, representing 195 species, 83 genera and 34 plant families. Per hectare species number averaged 64, basal area was 0.71 m2 and Fisher alpha, Shannon and Simpson diversity indices were 17.9, 3.1 and 11.4, respectively. There was oligarchic dominance of 10 plant families that represented 69% of total species richness, 92% of liana abundance and 92% of basal area, while ten dominant species accounted for 63% of abundance and 59% of basal area. Forty-one species (21%) were represented by one individual only. Most lianas were light-demanding, climbed their hosts by twining, and had conspicuous flowers, medium-sized leaves and animal-dispersed propagules. Liana abundance increased with abundance of medium-sized and large trees but was, surprisingly, independent of small-tree abundance. Canopy openness, soil moisture, and tree size were the most important environmental factors influencing abundance and distribution of lianas.

    In Chapter 3 I investigate changes in structural characteristics, diversity, recruitment, mortality and growth of the liana community over the thirteen years (1994 ¬- 2007). Liana density decreased from 750 (1994) through 547 (2001) to 499 (2007) stems ha-1, with concomitant declines in basal area and above-ground biomass. Despite lower stem densities the species richness remained constant over time. Total liana recruitment rates decreased slightly from 8.6% per year in the first period to 6.6% in the second, but this decrease was not significant. Liana mortality rates decreased significantly from 7.2% to 4.4% per year over the two census intervals. Diameter growth rates and survival increased with liana stem diameter. Surprisingly, liana abundance in Ituri showed recent declines, rather than recent increases, as has been reported for tropical and temperate forests in the Americas. Interestingly, changes in overall liana community structure and composition were mostly driven by one species only: the dramatic collapse of superabundant Manniophyton fulvum between the first and the second census.
    In chapter 4 I investigated species-specific dynamics of the 79 most abundant liana species, representing 13,156 of the stems (97% of total) in two 10-ha plots. I evaluated their demographic performance and the relation if the vital rates (growth, mortality, recruitment) to the species abundance and four functional traits (climbing strategy, dispersal syndrome, leaf size and light requirements) to determine across species variations and major strategies characterizing species. Vital rates shared a wide interspecific variation; species-specific recruitment rates varied from 0.0-10.9%, mortality rates from 0.43-7.89% over 13-year, and growth rates from -0.03-3.51 mm y-1. Most species had low to moderate rates. Species that grew fast tended also to recruit and die fast, but recruitment and mortality rates were not directly related, suggesting that species shift in absolute abundance over the 13 year period. However, with the exception of the collapsing Manniophyton fulvum population, species maintained their rank-dominance over time. Species growth declined with abundance, but recruitment and mortality rates were not related to abundance. The demographic performance of liana species varied weakly with their climbing strategy and dispersal mode but was, surprisingly, not related to their lifetime light requirements. A principle components analysis of liana strategies in terms of functional traits and vital rates showed that light demand, and dispersal syndrome were the most determining traits. Based on the PCA three functional guilds were distinguished. I conclude that old-growth forest liana species show a large variation in abundance and vital rates, and that density-dependent mechanisms are insufficient to explain the species abundance patterns over time.

    Lianas are thought to globally increase in density, but we have limited knowledge about the taxonomic patterns of change in liana abundance, and the underlying vital rates that explain changes in liana density. In chapter 5 the changes in abundance of 79 relatively abundant liana species are evaluated. The Ituri forest showed a pervasive change in liana population density in the last decade. 37 species changed significantly in their abundance over time: 12 (15% of total) species increased, and 25 (32%) species decreased. 42 (53%) species did not change. Of the 48 genera, 40% decreased and 52% stayed the same. Five of the 12 increasing species belonged to the Celastraceae, which also was the only significantly increasing family. Surprisingly, none of the four functional traits (lifetime light requirements, climbing mechanism, dispersal mechanism, and leaf size) was significantly associated with species change in population density. Many decreasing species, however, are associated with disturbed habitats and are short-lived. Many increasing species are late successional and longer-lived. Increasing species have a slightly higher recruitment, decreasing species a higher mortality. This study suggests that changes in the liana community result from forest recovery from past disturbances. Rising atmospheric CO2 level was not a likely explanation for liana change: more species declined than increased, and increasing species did not have higher growth rates. In the Ituri Forest local stand dynamics override more global drivers of liana change.


    The missing link : bridging the gap between science and conservation
    Hoeven, C.A. van der - \ 2007
    Wageningen University. Promotor(en): Herbert Prins, co-promotor(en): Fred de Boer. - [S.l.] : S.n. - ISBN 9789085047568 - 152
    natuurbescherming - wild - onderzoek - gegevens verzamelen - technieken - regenbossen - soorten - nature conservation - wildlife - research - data collection - techniques - rain forests - species
    Conservation biology is faced with an implementation crisis. This crisis is the result of a “knowledge-doing” or “assessment-planning” gap. One reason for this is that there is a discrepancy between systematic classical scientific assessments or surveys, and actual implementation in the field. This thesis explores the state of conservation biology by discussing the practicality of several research activities that are needed in most biodiversity conservation projects. Classical conservation science is compared and combined with newly developed methodologies. The objective was to produce a more comprehensive information package for conservation planning and implementation. Research activities were analysed on complementarity, cost and time constraints, and on the possibilities of integrating local knowledge. This study was conducted in GEF-Campo-Ma’an project in the tropical rainforest area of south Cameroon. In chapter 2 a new method of wildlife density estimation is explained, which is less time and money consuming, but yields comparable results with classical methods. Methods currently used for assessing wildlife density in rainforests are time and money consuming. The precision of the most commonly used methods is disputed, but accepted because more exact methods are not available. The method was tested in the field and compared with transect surveys in the area and with relevant literature. The PLEO (Pooled Local Expert Opinion) method is based on the knowledge of local experts. A number of hunters was asked to estimate wildlife abundance in a specified area, after which the density per km2 was calculated for 33 wildlife species. These estimates were pooled and extrapolated for the whole study area. Elephant (Loxodonta africana) density outside the National Park was estimated to be 0.06 animals per km2, and 0.3 inside. Buffalo (Syncerus caffer) density for the study area was estimated at 0.2 animals per km2 and gorilla (Gorilla gorilla) density at 1.05 per km2. Transect surveys carried out at the same time for considerably more money, taking far more time, produced too few data to calculate densities. The evaluation of the PLEO-method was favourable and the method offers a substitute for conventional methods of estimating wildlife density in rain forests. The methodology is simple and it can be incorporated in many tropical biodiversity and conservation projects. It can also be used for long-term monitoring of wildlife status in a given area. In contrast with classical methods, the PLEO-method is low in cost and assures local ownership of the results. In chapter 3 a new method is presented that ranks medium to large-sized mammals in a rainforest according to their vulnerability to extinction or to major population declines. It is a fast, efficient and cost-effective method to set priorities in conservation management. Information from the literature and local knowledge from hunters and forestry people were combined to assess the status of 33 wildlife species. The result is a vulnerability list, where species are ranked according to their vulnerability to major declines and extinction. To produce this list we developed a system where the risk-proneness of each species was determined on the basis of thirteen factors. These factors were assumed to be of importance to the survival of a population, and were scored with information from interviews with local hunters, and from the literature. The method was tested in the Campo-Ma’an area in south Cameroon. In this study the most vulnerable species was the mandrill, followed by the elephant, chimpanzee, and buffalo. Five of the ten most vulnerable species are on the IUCN red list of threatened species, which justifies the use of the new method to set local conservation priorities. We argue that for on-the-ground management this method provides a useful tool to allocate time and money to the species that need them most. Because detecting trends in wildlife populations remains difficult, other ways of monitoring are needed. Gathering socio-economical and biological data on bushmeat markets could be a relative easy way of monitoring the bushmeat trade. Although collecting data is fairly straightforward, analyses of these data are hardly ever conclusive on the sustainability of the off-take. Theoretical models that include as much variables as possible do perform quite well in simulations, but long-term, multi-variable datasets provide no clear-cut answer yet. Chapter 4 presents a survey that selected only a few factors that are thought to indicate the state of the trade, and analyzed the relations between these dependent factors and several fixed (independent) factors that are hypothesized to influence this state. The factors assumed to be indicative of the bushmeat trade are: the price, the state (the percentage smoked meat), and the diversity of the bushmeat for sale (in terms of number of species for sale). These are thought to be related to several factors that influence hunting pressure, which are: human population size (as a proxy for the demand for bushmeat); distance between local market and city markets; and distance to the National Park; and the wildlife density in the area surrounding the market. Two clear relations were found after analysis. These are a negative correlation between the price of the bushmeat and the distance to the city; and a negative correlation between the percentage of smoked meat at the market and the wildlife density in the area surrounding the surveyed market. The negative effects of roads on wildlife in tropical rainforests in Africa are poorly understood. Road construction has high priority in Africa, with as effect that negative impacts of roads on wildlife often are neglected. Chapter 5 provides information on the effects of roads on crossing behaviour of rainforest wildlife. Crossing probability of forest wildlife was analyzed for association with ten different factors that were linked to road presence or road construction. Factors were divided into three classes: vegetation cover, topography and human influence. Spoor plots were laid along a 32 km unpaved logging road that divides Campo-Ma’an National Park. Tracks of several species were found frequently (e.g., genets and porcupines); while others were found only sporadically (e.g., forest duikers and apes). Differences in crossing behaviour between plots along the road and in the forest interior supported the hypothesis that the presence of a road acts as a barrier for most species. The actual physical obstacles found along the road (e.g., logs, banks, etc.) proved to be highly negatively correlated with crossing probabilities. High vegetation cover was positively correlated to crossing probability. This study proves that roads have a large impact on wildlife, and indicates which factors could be altered during road construction and maintenance in order to mitigate these impacts, such as to maintain a high vegetation cover at shrub level up to the road, and to prevent the roadside from being blocked during construction. During the study described in chapter 5, the colonisation of roadsides by an invasive plant species was discovered. We surveyed the level of invasion of the roadsides by the invasive shrub Chromolaena odorata and found that native plant species of the African ginger family (Zingiberaceae) were outcompeted (chapter 6). Zingiberaceae form a key resource for the lowland gorilla. Abundance of these gingers has been largely reduced through displacement by Chromolaena odorata in two years time in Campo-Ma’an National Park in Cameroon. The invasion of this shrub in the whole rainforest region of central Africa and subsequent disappearance of the original vegetation threatens the gorilla in its already precarious existence. Merging local knowledge in classical scientific activities is possible in a scientific sound way. The advantages in terms of cost and time benefits, plus the potential of increased commitment of the local population to conservation argues for this approach to be adopted on a larger scale. When the first three case studies (chapters 2, 3, and 4) are combined, species and site specific information can be generated that provides on-the-ground management with the means to set conservation priorities. By combining the vulnerability assessment, the base-line density assessment and the level of exploitation in the market survey, a comprehensive analysis of the state of the wildlife emerges. The risk of not noticing threatened species is in this way reduced. Although more practical and solution-based research within conservation biology is imperative for more effective conservation, fundamental and long-term classical research remains necessary. But only, given the time and money constraints, if they are based on specific questions posed by conservation planners and practitioners. The case studies (chapters 5 and 6) are examples where there is a clear link between classical scientific research and the requirements from conservation planners. Reconsideration of the role of conservation science is necessary, and testing of new methods proves that it is worthwhile to leave the beaten track. This does require a change of attitude of the conservation biologists. Only by trying new approaches and by testing new methods can one advance conservation. This thesis provides a start by presenting case studies which should stimulate further progress in conservation biology.
    Spaceborne radar monitoring of forest fires and forest cover change : a case study in Kalimantan
    Sugardiman, R.A. - \ 2007
    Wageningen University. Promotor(en): Reinder Feddes, co-promotor(en): Dirk Hoekman. - [S.l.] : S.n. - ISBN 9789085046042 - 190
    tropische regenbossen - regenbossen - bosbranden - kroondak - remote sensing - radar - monitoring - digitaal terreinmodel - kalimantan - tropical rain forests - rain forests - forest fires - canopy - remote sensing - radar - monitoring - digital elevation model - kalimantan
    The devastation of tropical rain forests has been proven to have a significant effect on global climate change. The sustainability of these forests becomes a major concern for the international community. The Indonesian Ministry of Forestry (MOF) is eager to carry on forest inventory activities and to generate forest resources information.Advanced spaceborne radar techniques are a very promising tool to monitor forests. This technique is complementary with the existing spaceborne optical imagery which suffers too much from cloud cover. Radar provide reliable information on a regular basis and has been applied in various types of applications e.g. forest classification.

    The approach presented in this thesis includes. Firstly, multi-temporal classification of spaceborne Synthetic Aperture Radar (SAR) data using Iterated Conditional Modes which is proposed as a fast step of Maximum Likelihood classification in order to circumvent the slow image segmentation step. Secondly, slope correction dealing with steep slopes that considerable has geometric distortion. Thirdly, textural analysis has been applied to derive additional information layers in multi-temporal classification from fine structures in the radar images.

    The study focuses on three test site areas i.e. Sungai Wain test site area, the Gunung Meratustest site area and the NASA AirSAR PacRim-II test site area.This area experienced long drought periods associated with the El Niño Southern Oscillation (ENSO)phenomenon. For this study the severe ENSO event of 1997 - 1998 is of particular interest.Forestfires occur almost every year in this test site area, however,each event is specific in intensity and extent. A longer time series ofradar images takes every event observations into account.

    The results show high accuracy ranging from 85.2% to 98.8% for almost all land cover types. Slope correction has positive effect, but in accuracy does not seem to be very high. It is showed that the induced slope correction is around 1 dB while values up to 10 dB were expected. The resolution of the digital elevation model is an important factor for the correction of relief in spaceborne SAR data. When the resolution is too coarse, i.e. spatial features of slope correction are coarser than the actual structures; the pattern of relief will be flattened out. Utilization of textural features yields a significant improvement of overall classification accuracy, which increases from 36.5% to 48.5%.

    The approach developed for the Gunung Meratus has a wide applicability. This approach seemed to be sufficiently mature to apply it for others areas, for example the Mawas and Sebangau peat swamp forest area. This methodology of radar monitoring system may have the potential to become the core system for 'fast illegal logging response' within the Indonesian MOF.

    The implementation of the SAR monitoring for the Indonesian MOF is speeding up the ongoing decentralization policy. Recommendations are offered here to the Indonesian MOF, particularly for local authorities to enhance their capability in providing fast, accurate, and reliable information on forest condition. This capability will ensure the sustainability of the remaining tropical rain forest in the country.
    Birds, traditional coffee plantations and spatial complexity: the diversity puzzle
    Leyequien Abarca, E. - \ 2006
    Wageningen University. Promotor(en): A.M. Cleef; Andrew Skidmore; V.M. Toledo; Fred de Boer. - [S.l. ] : S.n. - ISBN 9789085044161 - 240
    vogels - regenbossen - habitats - soortenrijkdom - biodiversiteit - soortendiversiteit - beplantingen - coffea - ecologie - biologische mededinging - mexico - birds - rain forests - habitats - species richness - biodiversity - species diversity - plantations - coffea - ecology - biological competition - mexico
    As the current accelerated and increasing loss of biological diversity have become apparent land managers and ecologists have sought to identify significant habitats to the preservation of biodiversity. A critical component of biodiversity protection is the understanding of the ecological forces shaping the species diversity patterns. The aim of this study is to gain insight in the local and regional factors ultimately controlling species persistence and coexistence. The conceptual background of this study is that of a diversified multiple-use landscape matrix, that is used and managed and where "natural areas" can be embedded. Neotropical bird species are currently under threat as their breeding grounds suffer from degradation and loss because of intensification of land use. The fieldwork of this thesis was conducted in the northeasternmountain range of Puebla, Mexico. This region represents an important area for the conservation of resident and migrant birds, as it is located in a strategic position at the Nearticand Neotropicalbiogeographicboundary. It also forms part of the migratory route for Nearctic-Neotropicalbirds. Moreover, despite the loss of primary forests in the region, one of the main land uses in the study area is traditional shade coffee plantations which remain as an important forested habitat for birds.

    An important issue in conservation biology is the monitoring of community trends to provide reliable information of species diversity and their status, for fast and efficient identification of conservation priorities. In chapter 2, we analyse the use of a double-observer point count approach and mist netting for assessing bird species richness during migration. We assess the relative biases, costs and efficiency of both techniques to aim optimisation in the design of large-scale monitoring. We found that the double-observer point count technique was the most effective in the total species richness completeness and presented lower total effort in comparison to mist netting. The performance of point counts is higher than mist netting in the detection of new bird species in the research area, even after a large sampling effort.However, mist netting significantly detected a higher proportion of understoryspecies in comparison to point counts, though we found opposite results for migrant species.Finally, the cost-efficiency analysis showed that the modified double-observer point counts required less total effort thus decreasing total monetary costs compared to mist netting. One of the main problems in conservation in Latin America is the accelerated deforestation and conversion to monocultures and grazing lands that has direct effects on Neotropicalavian communities (i.e. resident and migrants) leading to a major loss of habitat, and landscape fragmentation. In chapter 3, we analyse how fragmentation and habitat loss in the landscape influences the bird species richness patterns. We examine the relative individual and combined influence of these two factors on species richness in an avian metacommunity. Moreover, we compare the difference in explanatory power of individual and combined influence of both factors. The response of species richness to habitat fragmentation shows a unimodalresponse at landscape level, anda negative response to habitat loss. The combined influence of fragmentation and habitat loss did not offer a better approximation of species richness response. This suggests that there is no interaction between the effects of fragmentation and habitat loss. Assessment of the effects of habitat fragmentation and loss under the current situation of growing human perturbation in natural habitat is fundamental in conservation and landscape management.

    An important ecological force structuring ecological communities is interspecific competition. Body mass is an easily determined characteristic of animals that probably influences competition strength. In chapter 4, our objective is to examine the effect of body size (mass) on competitive interactions between competing pairs of bird species. Our results indicate that there is a significant negative relationship between bird body mass ratio and the competition strength i.e.; the larger the body mass ratio, the lower the competition strength thereby suggesting that high variation in body sizes amongst sympatric species may promote coexistence in communities. Moreover species that have a greater overlap in resource use tend to exhibit stronger competition than species that overlap less in their resource use. In chapter 5, the influence of spatially explicit bio-physical variables at multiple scales on a bird community is analysed. We argue that biological communities are organised at multiple functional spatial scales and interactions between these scales determine both local and regional patterns of species richness. We use a multiple scale approach with plot, patch and landscape level variables using abundance and presence-absence data. Our results demonstrate that landscape variables explain most of the variation in bird species in both abundance and presence-absence analyses in all explanatory sets. Interestingly, results demonstrate that variation in community structure was described best at family-level than at genera- or species-level. Our results show that shade coffee plantations is one of the main land covers that positively influence the species richness, thus providing habitat for neo-tropical migrants and forest-dependent birds (e.g.; in this study some endemic and protected species). Thus, selecting the appropriate scale(s) of management in conservation strategies is essential in conservation of bird communities.

    The use of remotely sensed data has great potential to aid in explaining species diversity and community assemblage patterns at multiple scales. Besides, it can help to optimise sampling strategies or to allow testing of hypotheses regarding the spatial correspondence of species diversity patterns among different taxonomic groups. In chapter 6, we review how remote sensing has been used to assess terrestrial faunal diversity, with emphasis on proxies and methodologies, while exploring prospective challenges for the conservation and sustainable use of biodiversity. We grouped and discussed papers dealing with the faunaltaxamammals, birds, reptiles, amphibians, and invertebrates into five classes of surrogates of animal diversity: 1. habitat suitability, 2.photosynthetic productivity, 3. multi-temporal patterns, 4. structural properties of habitat, and 5.forage quality. It is concluded that the most promising approach for the assessment, monitoring, prediction, and conservation of faunal diversity appears to be the synergy of remote sensing products and auxiliary data with ecological biodiversity models, and a subsequent validation of the results using traditional observation techniques.

    In chapter 7, I present the conservation implications of shade coffee plantations as a refuge for Neotropicalbirds. The scenarios of loss and conversion of shade coffee plantations for biodiversity conservation and carbon sequestration emphasise on the ecological services that this agro-ecosystem provides. The reduction of shade coffee plantations in the studied region will have a deleterious effect on the species richness of e.g., resident birds with an estimated decline of 0.006 in species richness for every hectare the coffee area is reduced. These results could have significant consequences for conservation strategies as the amount of traditional shade coffee plantations has a positive linear relationship with the species richness of resident birds ( p <0.001). Moreover, in our research area the calculated carbon stock of the total area covered by shadecoffee plantations is257,789 t C, which represents 1,288,943 USD in carbon credits. Thus, with a reported current conversion rate of 0.4 % the results in carbon loss will be devastating in just one year. Although the conversion rate for the research area is unknown we approximate an almost negligible rate of conversion compared to the previously reported. The potential for the coffee producers as suppliers of carbon sequestration is calculated in approximately 105 USD/ha, which represents a considerable income compared to approximately an average of 59 USD/ha per coffee harvest. In addition, the value of shade coffee plantations as a component of the anthropogenic matrix is stressed in this study. Traditional shade coffee plantations are cultivated mainly by small-scale community-based growers, the majority of them belong to some indigenous group.

    The indigenous form of utilisation of this tropical agroecosystemsdenotes a multiple use strategy, which can be called adaptativemanagement. This indigenous adaptativemanagement has obvious socio-economic as well as ecological benefits. The ecological advantages of shade coffee agroecosystemsare clear: a) high biodiversity maintenance, b) regulation of carbon cycle, c) soil protection, d) regulation of hydrological cycle-> can I translate this with "buffer drying out the soil. I cant think of a good word for regulate ande) preservation of forest cover. The economic benefits derived from this tropical agroecosystemsare sources of goods, services and energy for household subsistence and products for local, regional and international markets. To increase the effectiveness of conservation management, the value of suitable land for multiple uses, as a component of the anthropogenic matrix should be considered. For example, in the case of tropical bird species, such linkages could be maintained by using the man-modified landscapes, e.g.; traditional shade coffee plantations as these areas also harbour an ecological value as habitat
    The African rain forest during the Last Glacial Maximum an archipelago of forests in a sea of grass
    Leal, M.E. - \ 2004
    Wageningen University. Promotor(en): Jos van der Maesen; A.M. Cleef. - Wageningen : S.n. - ISBN 9789085040378 - 96
    caesalpinioideae - regenbossen - soorten - soortendiversiteit - plantengeografie - droogteresistentie - klimaatverandering - uitsterven - gabon - afrika - glaciale perioden - pleistoceen - holoceen - caesalpinioideae - rain forests - species - species diversity - phytogeography - drought resistance - climatic change - extinction - gabon - africa - glacial periods - pleistocene - holocene
    In centralGabon(Africa) the distribution ecology of the Caesalpinioideae tree species (Leguminosae) were studied in two separate low rainfall areas which straddled the same geological transition from upland to lowland. The principle environmental force arranging their distribution was regional drought stress during the two dry seasons. These drought sensitive tree species were able to survive in the two forest-savannah mosaics because local compensation was provided by the permanent presence of water along some of the streams and by reduced exposure (shade) in narrow valleys. According to the Pleistocene forest refuge theory the Caesalpinioideae in the two study areas arrived during the last 10,000 years (Holocene) from the closest forest refugium- the Chaillu Massif (80 km further south). This part ofGabondid not become deforested during the Last Glacial Maximum when climate was much drier because cloud forest conditions in this elevated area compensated for the shortage of rainfall. Arrival of the Caesalpinioideae trees by migration from this refuge area by their normal dispersal mechanism of explosively opening pods is excluded as their advance over the Holocene was only 36 km. Also arrival through occasional long-distance dispersal events by water along watercourses is not viable, because species composition along streams does not show a decreasing gradient with distance from the refuge area. Long-distance dispersal events in the past now obscured by an equilibrium situation of species distributions with present-day habitat is also not possible as the similar hills and lowland in the two study sites are inhabited by very different species. The only conclusion is that the Caesalpinioideae survived the Last Glacial Maximum in the study areas themselves. The present-day general presence of these Caesalpinioideae in the African rain forest between the former forest refugia shows that small pockets of forest persisted in the then savannah.
    Biodiversity of west African Forests. An Ecological Atlas of Woody Plant Species
    Poorter, L. ; Bongers, F.J.J.M. ; Kouame, F.N. ; Hawthorne, W.D. - \ 2004
    Oxon : CABI Publishing - ISBN 9780851997346 - 520
    houtachtige planten - regenbossen - bossen - biodiversiteit - taxonomie - plantengemeenschappen - plantengeografie - bosecologie - west-afrika - woody plants - rain forests - forests - biodiversity - taxonomy - plant communities - phytogeography - forest ecology - west africa
    Sustainable Management of African Rain Forest Part I: Workshops
    Foahom, B. ; Jonkers, W.B.J. ; Nkwi, P.N. ; Schmidt, P. ; Tchatat, M. - \ 2001
    Wageningen : The Tropenbos Foundation - ISBN 9789051130478 - 274
    regenbossen - bosbedrijfsvoering - duurzaamheid (sustainability) - landgebruiksplanning - plattelandsgemeenschappen - participatie - biodiversiteit - houtteelt - zwerflandbouw - houtkap - kameroen - rain forests - forest management - sustainability - land use planning - rural communities - participation - biodiversity - silviculture - shifting cultivation - logging - cameroon
    Sustainable Management of African Rain Forest. Part II: Symposium
    Jonkers, W.B.J. ; Foahom, B. ; Schmidt, P. - \ 2001
    Wageningen : The Tropenbos Foundation - ISBN 9789051130515 - 159
    regenbossen - bosbedrijfsvoering - duurzaamheid (sustainability) - landgebruiksplanning - plattelandsgemeenschappen - participatie - biodiversiteit - houtteelt - zwerflandbouw - houtkap - kameroen - rain forests - forest management - sustainability - land use planning - rural communities - participation - biodiversity - silviculture - shifting cultivation - logging - cameroon
    The social dimension of rainforest management in Cameroon : Issues for co-management
    Berg, J. van den; Biesbrouck, K. - \ 2000
    Kribi : The Tropenbos-Cameroon Programme - ISBN 9789051130430 - 99
    bosbedrijfsvoering - bosbouw - tropische regenbossen - bedrijfsvoering - regenbossen - gemeenschappen - bosbestanden - bosproducten - wetgeving - participatie - plaatselijke bevolking - kameroen - forest management - forestry - tropical rain forests - management - rain forests - communities - forest resources - forest products - legislation - participation - local population - cameroon
    Diversity and dynamics of mycorrhizal associations in tropical rain forests with different disturbance regimes in South Cameroon
    Onguene, N.A. - \ 2000
    Agricultural University. Promotor(en): L. Brussaard; T.W. Kuyper. - S.l. : S.n. - ISBN 9789058082930 - 167
    mycorrhizae - mycorrhizaschimmels - ectomycorrhiza - vesiculair-arbusculaire mycorrhizae - symbiose - bosecologie - regenbossen - tropische regenbossen - bosbedrijfsvoering - bosschade - entstofdichtheid - kameroen - mycorrhizas - mycorrhizal fungi - ectomycorrhizas - vesicular arbuscular mycorrhizas - symbiosis - forest ecology - rain forests - tropical rain forests - forest management - forest damage - inoculum density - cameroon

    The present study documents the occurrence of mycorrhizal associations in the rain forests of south Cameroon. All species investigated are mycorrhizal. Most timber species form arbuscular mycorrhiza, but some timber species, which usually occur in clumps, form ectomycorrhiza. Species diversity of ectomycorrhizal fungi in the undisturbed rain forest is substantial, with more than 125 species having been recorded. Inoculum potential of arbuscular mycorrhizal and ectomycorrhizal fungi is high in the undisturbed rain forest. The shifting cultivation cycle increases inoculum potential of arbuscular mycorrhizal fungi, but lowers inoculum potential of ectomycorrhizal fungi to various extent.

    On sites of forestry practices (skid trails, landings) inoculum potential of arbuscular mycorrhizal and ectomycorrhizal fungi is very substantially reduced and recovery rates are low. Mycorrhizal colonisation and seedling growth are positively correlated with mycorrhiza inoculum potential. Inoculum potential of arbuscular mycorrhizal fungi and performance of seedlings of arbuscular mycorrhizal trees can be boosted after inoculum addition. Both inoculum quantity and inoculum quality are important criteria for inoculation practices. Ectomycorrhizal inoculum potential cannot be increased through inoculum addition and management of the intact ectomycorrhizal network is necessary for maintenance of the ectomycorrhizal tree species.

    Key words : Arbuscular mycorrhiza, ectomycorrhiza, disturbance, rain forest, diversity, inoculum potential, Cameroon, forestry practices

    Forestry for mitigating the greenhouse effect : an ecological and economic assessment of the potential of land use to mitigate CO2 emissions in the Highlands of Chiapas, Mexico
    Jong, B.H.J. de - \ 2000
    Agricultural University. Promotor(en): R.A.A. Oldeman. - S.l. : S.n. - ISBN 9789058082664 - 220
    landgebruik - regenbossen - landtypen - graslanden - landbouwgrond - gedegradeerde bossen - koolstofcyclus - kringlopen - kooldioxide - broeikaseffect - koolstof - simulatiemodellen - systeemanalyse - mexico - land use - rain forests - land types - grasslands - agricultural land - degraded forests - carbon cycle - cycling - carbon dioxide - greenhouse effect - carbon - simulation models - systems analysis - mexico

    The present study intends to answer some of the important questions that arise when translating projects that have an ecological potential to mitigate carbon excesses, into actual implementation of these projects in a farmer-dominated landscape. Farm and community forestry projects for greenhouse gas mitigation in such environments would involve numerous participants, a high variety of small-scaled systems spread over large areas, with individual adaptations of general management procedures due to personal interests, local conditions, and previous experiences. In this book the results are presented of a study to estimate the flux of carbon from the terrestrial ecosystems to the atmosphere from the 1970s and 1990s of an intensively impacted and highly fragmented landscape. About 20 x 10 6 MgC were released to the atmosphere during the period of time covered by the study. Approximately 34% of the 1975 vegetation carbon pool disappeared. A feasibility study was carried out to (i) identify farmer preferred and ecologically viable agroforestry/forestry systems and their ex ante carbon sequestration potential; and to (ii) assess the economic potential of carbon offsets of such systems.

    A total of five land-use systems were considered viable, while farmers presented local adjustments in preferred species, planting arrangements, and rotation times. The carbon sequestration potential varied highly between the systems and the regions (from 26.7 to 338.9 MgC ha -1 ). The total cost of one MgC ha -1 varied between $US 1.84 and 3.98 for the systems selected in the Tzeltal region and between $US 1.47 and 11.15 for the systems in the Tojolabal region. The differences in costs within the same region were due to differences in establishment and opportunity costs, whereas the differences between the two areas were due to differences in the carbon sequestration potential of the regions. The carbon sequestration potential of the Highlands of Chiapas was estimated, based on an incentive program that would stimulate small farmers and rural communities to adopt biomass-accumulating measures, such as agroforestry or improved forest management. It was estimated that 38 × 10 6 MgC could be sequestered for under $US 15 MgC -1 , of which 32 × 10 6 MgC by means of sustainable forest management. The choice of a baseline rate of biomass loss in the "business-as-usual" scenario remains a critical issue to estimate the carbon sequestration potential of forestry.

    The main sources of uncertainties observed in the calculations of the GHG-offset potential of a forestry project were related to: (i) classification of LU/LC types, with observed differences of up to around 8% in land cover estimations; (ii) estimation of C-stocks within each LU/LC type, with uncertainties varying from around 13 to 34% in total C-stock; (iii) historical evidence of LU/LC changes and related GHG fluxes applied in baselines, giving rise to uncertainties of up to about 16% in the estimation of fluxes, whereas varying baseline assumptions produced differences between 31 and 73% in the C-mitigation calculations, with levels of uncertainty in the differences of up to 74%; and (iv) simulation techniques used to calculate future baseline and project C-fluxes, which generated uncertainties of up to around 10% in overall C-mitigation estimations.

    A self-reporting system with on-site spot-checks is the most appropriate method to assess the impact on carbon fluxes of a farm-forestry project, which typically include a high diversity of small-scale systems and numerous participants. The monitoring and evaluation procedure outlined in this study, facilitates the collection of field data at low cost, helps to ensure that the systems continue to address the needs of farmers, and gives the farmers an understanding of the value of the service that they are providing.

    Any method to estimate carbon dynamics has to deal with sources and levels of variability and uncertainties in data. In this dissertation various approaches were used to estimate the impact of variability or uncertainty in data or assumptions. In Chapter 3, the standard deviation of collected biomass data was used as an indicator to estimate the confidence interval of the regional C flux. In Chapter 4, the uncertainty of information was dealt with by varying tree growth due to expected differences in site conditions. In Chapter 5, a sensitivity analysis was used to test the impact of baseline emission assumptions and capital interest rates on the cost of mitigating one Mg carbon. Varying baseline assumptions and carbon transfer parameters within a forest ecosystem was used in Chapter 6 to identify the most important sources of error in the C mitigation estimation of forestry projects.

    Introduction de la bionomie dans la gestion des forets tropicales denses humides
    Vooren, A.P. - \ 1999
    Agricultural University. Promotor(en): R.A.A. Oldeman; J.L. Guillaumet. - S.l. : S.n. - ISBN 9789058081148 - 220
    regenbossen - bosbedrijfsvoering - bosecologie - tropen - ivoorkust - rain forests - forest management - forest ecology - tropics - cote d'ivoire

    - INTRODUCTION OF BIONOMICS IN TROPICAL RAIN FOREST MANAGEMENT -

    Conservation of tropical rain forests as renewable resources is governed by the bionomics of the forest ecosystem. Bionomics are here used as the set of conditions that govern the development and existence of an organism, species or biological system in a changing environment. These "life rules" should be considered to represent thresholds to the kinds of use that can be made of natural biological systems without endangering the further existence of its composite species.

    Studies of the thresholds in sustainable use of tropical rain forest have been conducted in the Ivory Coast. An undisturbed relict of the West-African rain forest belt, preserved in Taï National Park, provides possibilities to study natural processes of forest dynamics and diversity. The main focus was on occurring variations in forest composition, matrix and architecture along slopes in the undulating landscape. Further studies were made of forest dynamics through the occurring patterns in tree mortality and the conspicuous ageing and die-back features of canopy trees. Data on forest composition and dynamics were collected in two forest plots, one of 7 hectares established in 1977, covering a gentle slope in the middle of a watershed of a first order tributary of the Cavally River, and another of 10 hectares, established in 1981, on a steeper slope near the border of the same basin.

    A more detailed study is reported on the ageing and die-back processes that occur in two characteristic canopy tree species. Crown development sequences were therefore established for the species Piptadeniastrum africanum and Pycnanthus angolensis. The die-back patterns in individual tree crowns are discussed in relation to possible changes in their physiological state. Large-scale aerial photographs of these two tree species were made and showed the possibilities for reconnaissance of the described ageing features in aerial surveys. In the end conclusion is stated what the possibilities are for the introduction of a bionomical approach in conservation oriented management of tropical rain forests as restrictively used, low yielding timber resources. Therefore, the principal rules that have appeared in the reported studies on forest composition, architecture and dynamics are summarised and the possibilities are discussed of the reconnaissance of senescent trees in aerial surveys and by field observations.

    Fighting for the Rain Forest: war, youth and resources in Sierra Leone.
    Richards, P. - \ 1996
    London [etc.] : James Currey [etc.] - ISBN 9780852553985 - 198
    jeugd - oorlog - bosbedrijfsvoering - regenbossen - milieueffect - geschiedenis - sociale structuur - sierra leone - west-afrika - vrede - youth - war - forest management - rain forests - environmental impact - history - social structure - west africa - peace
    A study of the methods of warfare, the youths involved and the aspirations for schools and jobs that motivates them to fight. The author argues that the war can only be understood in the context of old traditions of social and technical management of the forest.
    Canopy dynamics of a tropical rain forest in French Guiana
    Meer, P.J. van der - \ 1995
    Agricultural University. Promotor(en): M. Wessel; M.J.A. Werger; F. Bongers. - S.l. : Van der Meer - ISBN 9789054854531 - 149
    bosbouw - kroon - kroondak - synecologie - regenbossen - vegetatie - frans-guyana - forestry - crown - canopy - synecology - rain forests - vegetation - french guiana

    The canopy dynamics (i.e. the formation and closure of canopy gaps) of a tropical rain forest in French Guiana are described. The formation of canopy gaps is investigated. The difficulties with gap size measurements are studied, and causes and consequences of treefalls and branchfalls are examined. It is concluded that canopy gap location is not random. Sod factors may make some areas in the forest hot spots of disturbances, whereas other areas are less frequently disturbed. Furthermore, the closure of canopy gaps and tree seedling performance in gaps are discussed. Recruitment in gaps is largely determined by the fortuitous occurrence of seedlings and sapling that were present before the gap was formed. Specialisation of species is discussed and its concluded that detailed information on micro-habitat availability (in gaps) and on micro-habitat needs of species may indicate which individuals at which location have the highest chance of survival. Finally, the potential application of these findings for application in forest practices are examined.

    Check title to add to marked list

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.