Дисертації з теми "Lao tropical forests"

Understanding how structure and function change across environmental gradients is a fundamental goal of ecology, with important applications in a changing world. In this dissertation, I explore how environmental variations in temperature and precipitation affect three-dimensional canopy structure, and how this, in turn, affects forest function. Characterising how climatic variations affect forest structure and function is particularly important in tropical forests, which are globally important carbon stores that have already shown vulnerability to climate change. The future of tropical forest carbon stocks is highly uncertain, with plant physiological responses representing the largest source of model uncertainties. As such, my dissertation research comprises empirical investigations into how tropical forests will respond to high temperatures and drought. Firstly, I examine tropical forest response to high temperature by conducting a comparison of natural forest sites and a tropical forest mesocosm using eddy-covariance data. I present evidence that high temperature declines in tropical forest photosynthesis are not due to direct temperature effects (i.e., that cause damage to the photosynthetic machinery), but instead are predominantly due to indirect temperature effects that result from concurrent increases in vapour pressure deficit (VPD). While both mechanisms reduce photosynthesis, the impact of increased VPD under future climate may be partly mitigated by enhanced water-use efficiency associated with rising atmospheric CO2 concentrations, suggesting that tropical forests may have opportunities for resilience in the face of global warming. The second part of my dissertation research examines how tropical forest canopy structure responds to seasonal dry periods and anomalous droughts on seasonal and interannual timescales, using data from ground-based LiDAR (Light Detection and Ranging). I show that total leaf area index (LAI) does not represent the seasonality of forest structure, since the upper and lower canopy levels exhibit divergent seasonal responses. The seasonal pattern of upper canopy LAI shows good agreement with the seasonal pattern of enhanced vegetation index (EVI) measured from satellites, suggesting that satellites are not capturing the response of the lower canopy. These results indicate that smaller trees are responding to seasonal water limitations and larger trees to light availability. I found that the response of canopy structure to anomalous (El Niño-induced) drought was similar to seasonal dry periods, but that the trends in LAI and vertical canopy structure were amplified. In particular, I document a delayed loss of LAI from the upper canopy following extreme drought, which supports the idea that while smaller trees may be more responsive to shorter, less severe dry periods, larger trees are more susceptible to prolonged or more severe droughts. Finally, I combine a long-term ground-based LiDAR dataset with tree inventory data in order to identify the mechanisms (i.e., changes in leaf area and/or woody biomass) of structural changes caused by droughts. I present evidence that loss of lower canopy LAI following an El Niño-induced drought was due to the mortality of small trees, not loss of leaf area, while an increase in LAI in the upper canopy predominantly resulted from plastic leaf area changes. If small trees are susceptible to drought-induced mortality and the incidence of droughts increases, this could prevent the recovery of tropical forests from drought-induced disturbances.

La riqueza de orquídeas en Colombia alcanza una cifra de 4.270 especies, sin embargo, nuevos hallazgos sugieren no haber llegado a un punto de inflexión. La condición epífita en el 69% de sus especies y su ubicación en el dosel, desfavorece su colección y registro, más aún, en ecosistemas fragmentados como el Bosque seco Tropical (Bs-T). Este ecosistema en Colombia, ocupó 9 millones de hectáreas y actualmente solo se mantienen 720.000 has, sin embargo, ha sido insuficientemente explorado y la flora epífita presenta grandes vacíos geográficos. La fertilidad del suelo y el relieve llano, facilitó el establecimiento de ciudades, el desarrollo de la agricultura, la ganadería, pero también aceleró la pérdida de especies vegetales. En los últimos 400 años la introducción de ganado bovino en la región del Caribe y Magdalena y 130 años, el cultivo de la caña de azúcar en el Valle del río Cauca, han sido las principales causas de la transformación. En este sentido, las orquídeas del Bs-T es el foco de atención de esta tesis, mejorar el conocimiento de su pasado, explorar su presente y planificar su futuro han sido abordadas empleando diferentes metodologías a escala regional y nacional. Una primera línea amplio el conocimiento de las orquídeas del Valle geográfico del río Cauca, (694.760 hectáreas y 2% de coberturas Bs-T) en un 112% y se completó un catálogo con 71 especies para esta bioregión al sur-occidente de Colombia. Del total, 10 especies son endémicas, una es nueva para la ciencia y 38 no se conocían en estudios previos. Se detectó afinidades florísticas con las tres unidades fisiográficos características, ocho de ellas son exclusivas de la Cordillera occidental, 15 de la Cordillera central, tres de la Llanura aluvial, en tanto que 25 especies son compartidas por las tres unidades fisiográficas. Se detectó un decrecimiento en la riqueza de especies en sentido norte-sur que guarda relación con el uso del suelo. Los resultados de presencia, evidencian la extinción local de 19 especies durante el último siglo, sugiriendo que el cultivo industrial de caña de azúcar, es el máximo responsable de la pérdida de biodiversidad. Una segunda línea se empleó un grupo de siete especies de orquídeas epífitas típicas del Bs-T de la región del Valle del río Cauca y Dagua para detectar los cambios en la distribución espacial y planificar su conservación frente al cambio climático (CC). El modelamiento fue realizado con Maxent con el escenario SRES-A2 de CC para el horizonte temporal (2080-2100). Los resultados muestran un incremento altitudinal para el escenario de CC y un incremento en la idoneidad en áreas de montaña media en detrimento de las áreas basales donde actualmente se encuentran las orquídeas. La concentración de áreas idóneas fue mayor en la cordillera occidental que en la Cordillera central. Variables como la accesibilidad, el tipo de cobertura, la temperatura y la disponibilidad hídrica, explican el 88,6% del modelo. Se proponen el establecimiento de Corredores de Migración Altitudinal -CMA- como alternativa frente a una pérdida de biodiversidad en el Bs-T. Una última línea identifica en cinco bioregiones de Bs-T en Colombia, los cambios espacio- temporales de un grupo focal de 12 especies. Se empleó el algoritmo usado por MaxEnt y el escenario de emisiones SRES 8.5 para dos periodos: (2030) y (2050). Los resultados muestran un desplazamiento altitudinal respecto al presente condicionado por variables como: temperatura, accesibilidad, y la precipitación. Las áreas de montaña media, incrementarán su idoneidad en detrimento de las tierras bajas. Los umbrales de polinizadores (euglossini), disponibilidad de forófitos, distancias a coberturas de Bs-T y áreas protegidas, sugieren mejorar la conectividad entre tierras bajas y zonas de montaña media. Se presentan 69 nichos climáticos como estrategia de conservación frente al cambio climático.
Orchid diversity in Colombia reaches 4,270 species; new discoveries, however, suggest that an asymptote has not yet been reached. The epiphytic condition in 69% of orchid species and their location in the canopy makes it difficult to collect and register them, even more so in fragmented ecosystems such as Tropical Dry Forest. This ecosystem in Colombia occupied 9 million ha, of which at present only 720,000 ha remain. Nevertheless, this ecosystem has been insufficiently explored, and there are large geographic gaps in our knowledge of the epiphytic flora. In the last 400 years, the introduction of cattle in the Caribbean and Magdalena regions, and in the last 130 years, the cultivation of sugar cane in the Cauca Valley, have been the main causes of this transformation and accelerated the loss of plant species. In this sense, the orchids of the Tropical Dry Forest are the focus of attention of this thesis, in order to improve knowledge of their past, explore their present, and plan their future, using different methods at regional and national scales. A first line of research augmented knowledge of the orchids of the geographic Cauca Valley (694,760 ha and 2% of coverage by Tropical Dry forest) by 112% and completed a catalogue with 71 species for this bioregion of southwestern Colombia. Of the total, 9 species are endemic, one is new to science, and 38 were not known in previous studies. A second line of research used a group of seven typical epiphytic species of orchids of Tropical Dry Forest of the Cauca and Dagua river valleys to detect changes in spatial distribution and plan their conservation with respect to climate change. Modeling was carried out with MaxEnt, with the scenario SRES-A2 of climate change for the time horizon 2080-2100. The results show an altitudinal increase for the climate change scenario and an increase in suitability in mid-mountain areas, with a decrease in suitability of basal areas, where orchids are found at present. The concentration of suitable areas was greater in the Western Cordillera than in the Central Cordillera. Variables such as accessibility, type of coverage, temperature, and water availability explain 88.6% of the model. The establishment of Altitudinal Migration Corridors is proposed as an alternative for dealing with biodiversity loss in Tropical Dry forest. A final line of research identifies spatial-temporal losses of a focus group of 12 species in five bioregions of Tropical Dry Forest in Colombia. The algorithm of MaxEnt was used, with a scenario of emissions SRES 8.5 for two periods, 2030 and 2050. The results show an altitudinal displacement relative to the present, conditioned by variables such as temperature, accessibility, and precipitation. Mid-mountain areas will increase their suitability, and lowlands will decrease in suitability. The thresholds for pollinators (Euglossini), availability of tree hosts, and distances to coverage of Tropical Dry Forest and protected areas suggest that connectivity between lowlands and mid-mountain zones should be improved. Sixty-nine climatic niches are presented for Colombia as a conservation strategy for adapting to climate change.

Forest and product certification was initially promoted as a means of enhancing sustainable management of forests in the tropics. However after almost two decades, there is still very little evidence of certified timber products originating from tropical countries. A number of approaches have been suggested to enhance the growth of forest certification in the tropics. These approaches such as that of the Forest Stewardship Council, Global Forest Trade Network of the World Wide Fund for Nature (WWF), Sustainable Forest Initiative and various private sector initiatives have all failed to facilitate forest certification. Therefore to enhance the development of forest certification in Ghana, the research work amongst others, draws on experiences in certification from other sectors such as cocoa, fisheries, tourism and oil palm to develop a model for promoting forest certification in Ghana. The research work uses elements identified in the literature review in developing a questionnaire for the survey of timber firms in Ghana. The research work identified stakeholder consultations, legal framework, resource rights, and the regulation of the domestic market as key elements for promoting forest certification in Ghana. The research recommends a phased approach to promoting forest certification with the first phase being verification of legality that adopts the European Union Forest Law Enforcement, Governance and Trade (FLEGT) and the Voluntary Partnership Agreement (VPA) initiative. The study identifies this approach not only as a means of reducing cost to the private sector in pursuing forest certification but a means of drawing on support measures to enhance the regulation of the domestic market; a key component for promoting forest certification. The report argues that it is only through a well regulated domestic market can tropical timber producing countries achieve sustainable forest management and hence forest certification. The domestic market is therefore seen as a strong means of promoting certification since it will be internalised in the producing countries. None of the research on certification has so far identified the domestic market as a key factor to promoting forest certification and the research work argues that the slow pace of certification has been the lack of demand for certified products on the domestic market. Developing the domestic market is therefore seen as a key policy instrument for promoting the uptake of forest certification in Ghana and the tropics in general.

This thesis analyzed the dynamics of tree radial growth at different time-scales in relation to climate and drought in two tropical dry forests (TDFs) from Colombia (Tuluá) and Bolivia (INPA). The specific objectives were: (i) To assess intra-annual patterns of radial growth (radial- increment dynamics and xylogenesis) in ten coexisting tree species from Tuluá and INPA and determine their relationship with climate and leaf phenology. (ii) To analyze the effects of climate and drought on long-term radial growth at different time-scales using dendrochronology in seven coexisting deciduous tree species from INPA. (iii) To evaluate the long-term radial growth responses to changes in climate water balance and determine their relationship with sapwood density in seven coexisting deciduous tree species from INPA. At intra-annual scales it was found that: (i) cambium reactivation and xylem growth of tree species occurred during the wet season, reflecting the influence of high precipitation and a positive water balance on the development of new xylem cells. (ii) In the semi-deciduous tree species from Tuluá the xylem growth period overlapped with the wet season, whereas, in the deciduous tree species from INPA, the growth period started at the mid wet season, when the tree crowns were fully developed. (iii) Temperature, as a determinant factor in the hourly fluctuations of both the vapor pressure deficit (VPD) and the evapotranspiration rate, could exert a huge influence on tree radial growth dynamics during the growing season. In Tuluá, the growing season was particularly associated with low temperatures and hence low VPD, while in INPA the growing season was related to high temperatures and VPD. Nevertheless, the high temperatures registered throughout the day at both TDFs negatively affected radial increment at hourly scales. Tree species could face the adverse dry conditions by restricting growth to periods of the day when temperatures are low. (iv) Stem shrinkage and swelling occurred at hourly to daily scales in all tree species, and most INPA tree species registered strong reversible shrinkage at monthly scales. Particularly, the climate controls on radial-increment dynamics varied between daily and monthly scales. At daily scales, there was a positive effect of high precipitation and positive water balance and a negative effect of VPD on the increment phase, while at monthly scales the precipitation was the main variable affecting radial increment positively. At inter-annual scales it was found that: (i) The tree radial growth showed a positive relationship with precipitation and climate water balance and a negative association with temperature, indicating that the tree species studied share high common growth variability in response to local climate. Nevertheless, the strongest response of growth to climate was species-specific, indicating that there was a differential sensitivity among tree species to these climate variables. (ii) The radial growth of all tree species responded positively to water balance during the wet season, but such responses differed among species as a function of their stem sapwood density. Specifically, sapwood density was negatively related to growth variability explained by water balance. Tree species with low-density wood and high production of sapwood were the most sensitive to water balance, whereas species with the opposite characteristics were the least sensitive ones. (iii) Tree species tolerated short-term droughts while they were particularly sensitive to long-lasting droughts. This indicates that tree species from the INPA site are predominantly sensitive in terms of growth reduction to long-lasting droughts. The most temperature-sensitive tree species, also showed the highest growth sensitivity to long-lasting droughts. In contrast, growth of the tree species with the lowest sensitivity to water balance, did not respond to long-term drought variability.
Esta tesis evaluó la dinámica del crecimiento radial a diferentes escalas temporales y determinó su relación con el clima y la sequía en dos bosques secos tropicales de Colombia (Tuluá) y Bolivia (INPA). A escalas intra-anuales se encontró que: (i) la reactivación del cambium y el crecimiento del xilema ocurre durante la época húmeda del año en ambos bosques. Esto refleja la influencia de las altas precipitaciones y los valores positivos del balance hídrico atmosférico en el desarrollo de las nuevas células del xilema. (ii) El período de crecimiento en Tuluá estuvo asociado a temperaturas bajas y, por ende, a un déficit de presión del vapor (DPV) bajo, mientras que en INPA la estación de crecimiento estuvo asociada a valores altos de temperatura y DPV. Sin embargo, en ambos sitios de estudio, las temperaturas altas registradas a lo largo del día afectaron negativamente el incremento radial a escalas horarias. Las especies pueden hacer frente a estas condiciones adversas, por ejemplo, restringiendo el crecimiento a períodos del día que registren temperaturas bajas, ya que la pérdida de agua asociada a la evapotranspiración también sería baja. A escalas inter-anuales se determinó que: (i) el crecimiento radial de todas las especies de INPA presentó una asociación positiva con la precipitación y el balance hídrico atmosférico y una relación negativa con la temperatura. Esto indica que todas las especies comparten una señal común de la variabilidad del crecimiento en respuesta al clima local. No obstante, la fuerza de la respuesta fue especie-específica. Esto indica que existe una sensibilidad diferencial entre las especies al clima. (ii) El crecimiento radial de todas las especies de INPA respondió positivamente al balance hídrico atmosférico durante la estación húmeda, pero esa respuesta fue diferente entre las especies en función de la densidad de la albura. La densidad de la albura fue negativamente relacionada a la variabilidad del crecimiento explicada por el balance hídrico. (iv) Las especies de INPA fueron resilientes a las sequías de corto plazo (estación seca anual), mientras que el crecimiento fue particularmente sensible a las sequías de larga duración (sequías multi-anuales), excepto en las especies con alta densidad de la albura.

Comment le droit international peut-il règlementer des phénomènes complexes ? Cette question se pose avec une acuité particulière en ce qui concerne la déforestation tropicale. En effet, les difficultés techniques et les intérêts divergents des États, découlant de l’interaction des multiples services assurés par les forêts, ont empêché l’adoption d’une convention internationale en ce domaine. Néanmoins, les négociations menées au sein du régime international du climat ont créé un mécanisme dit de « réduction des émissions résultant du déboisement et de la dégradation des forêts et le rôle de la conservation et de la gestion durable des forêts et du renforcement des stocks de carbone forestiers dans les pays en développement » (REDD+). Défini par un ensemble de décisions de la Conférence des parties à la convention-cadre des Nations-Unies sur les changements climatiques, il a déjà permis d’initier, sur le territoire des pays en développement, une amélioration substantielle du contrôle des ressources forestières et des réformes règlementaires et institutionnelles de grande ampleur. Notre étude se propose d’évaluer les spécificités du système normatif mis en place sur la REDD+. Elle a pour objet, en dépassant l’apparente faiblesse formelle des instruments juridiques sur lesquels il repose, de mettre en évidence sa portée normative. Elle révèle l’aptitude du droit international à règlementer des phénomènes complexes en donnant naissance à des systèmes juridiques adaptatifs. Elle démontre que la spécificité de tels systèmes normatifs réside dans la satisfaction de deux exigences opposées : la flexibilité et la sécurité juridique
How International law can regulate complex phenomenon? This question appears particularly relevant if we consider tropical deforestation. Technical issues and the opposite interests of States, stemming from interlinked services provided by forest, had prevented International community to adopt a convention on forests. Nevertheless, climate regime has recently created a so-called mechanism on « reducing emissions from deforestation and forest degradation in developing countries and the role of conservation and sustainable management of forests and enhancement of forest carbon stocks in developing countries » (REDD+). The normative framework laid down in decisions of the Conference of the parties has stimulated control improvement on forest resources and wide-ranging reform in developing countries. The study will evaluate the specificities of this normative system by going further its apparent normative weakness. It will expose how International law manage to regulate complex phenomenon by producing adaptive legal system. The study will demonstrate that the specific feature of this system lies in its ability to conciliate two opposite needs: flexibility and legal security

There has been a rapid change in forest and land cover globally, especially in tropical forests due to heavy deforestation. The highest rate of deforestation is found predominantly in the developing world. Tropical deforestation is a process of transforming forests into cleared land for other uses. Tropical deforestation is the second largest source of greenhouse gas emissions, responsible for about 17 - 30% of global emissions of CO₂ to the atmosphere, causing global warming. Precise and up to date information on the distribution and rate of forest cover change, especially in tropical regions, is required urgently for government policies aiming to control and manage forests and land development. Information on deforestation in tropical regions has been unavailable or inconsistent, including in the Lao PDR, due to socio-economic deficits, political interests and geographical constraints. Remote sensing technology has played a crucial role in providing the information required for reliable mapping and monitoring of forest cover changes at local, regional and global levels, but its application in tropical regions has been lagging. The overall goal of this research was to demonstrate and evaluate remote sensing methods for assessing and monitoring forest cover changes in tropical environments, particularly in the context of the Lao People’s Democratic Republic (PDR). The first aim of the research was to understand phenology of tropical forests and related vegetation types, which has been little studied. Improved understanding of the phenology of tropical forests and other land covers involved in forest clearance and land use change is an important step towards the use of remote sensing to identify and track changes in forest cover. Long-term averages of land surface temperature (LST) and enhanced vegetation index (EVI) 16-day time series of MODIS over the seven-year period from 2006 to 2012 were calculated and their monthly transitions compared for forests, and for land covers that commonly replace forests. The findings showed the complex interrelationship of LST and EVI and their monthly transitions for the different land covers: they each showed distinctly different intra-annual LST and EVI variations. Secondly, the research evaluated whether the combined use of these indices (LST and EVI) can classify these land covers. It was found that there was high overall accuracy of separation of land covers by long-term means of these indices (86%). This knowledge can be potentially useful for further broadscale mapping of land cover and detection of deforestation in tropical forests. For the third objective, the use of remote sensing time series data for detecting spatial and temporal changes in forest cover in tropical environments was tested. The disturbance index (DI) model was applied to detect spatial changes in different forest cover types, whilst the Breaks For Additive Season and Trend (BFAST) approach was used to examine temporal changes in these land covers. Results showed that the DI was capable of detecting vegetation changes during a seven-year period with high overall accuracy (82%); however, it showed low accuracy in detecting forest clearance (42%). The BFAST analysis detected abrupt temporal changes in vegetation in the tropical forests, especially in large conversions of mixed wooded/cleared area into plantation (from 2004 to 2007). From these two approaches, it was found that MODIS time series data may be suitable for continental and national monitoring of land cover, although it may not provide the level of geographic detail and accuracy required for local assessments. As a result of these findings, further analysis of forest cover changes at a finer resolution was required to improve monitoring approaches. Therefore, the fourth aim was to detect and map vegetation cover changes at a higher spatial resolution over a period of ten years between 2003 and 2012. Landsat ETM+ imagery from 2003 and 2012 was used in principal component analysis (PCA). This technique detected areas of vegetation cover change (both vegetation increase and loss) with high overall accuracy (87%). The results of these four studies provided new information on where and when recent forest cover changes have occurred in southern Lao PDR. The final step was to analyse the reasons underlying these changes. Thus, the final research task was to investigate potential factors associated with forest cover change in the study area, by using logistic regression analysis. The results of the analysis suggested that particular socio-economic and physical factors have a significant association with forest cover change. Forest clearance was associated strongly with elevation, distance to main roads and shifting cultivation practices. Meanwhile, vegetation increase was more likely to correlate with rubber plantations. Native forest and shifting cultivation lands were vulnerable to being converted into rubber plantations. This final research component contributes to a better understanding of ongoing land cover change processes to inform land use management. This is key information for policy and decision makers, and may be used to minimize deforestation and deal with potential risks associated with land cover changes.
Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2016.

Agroforests are model systems for ecological conservation in tropical agricultural landscapes because they integrate biodiversity conservation and rural livelihoods. Whether agroforests are long-term solutions for conserving biodiversity in agricultural landscapes may depend sapling regeneration of native forest trees in agroforests. In this dissertation, I ask two main questions: are native forest trees regenerating in agroforests and if so, what are the ecological and social drivers? I tested the influence of potential seed sources from both the landscape and parent trees found in the agroforest. I also examined how a set of social factors affected native forest tree regeneration. The social drivers I tested include tree management and use, land tenure and state-restricted rights to harvest native timber. I found that a number of native pioneer species are regenerating at relatively high frequencies and abundances. I also found that many secondary native forest tree species are also regenerating although their sapling are found less frequently and at lower abundances. Most primary forest tree species present as adults are not regenerating and lacked sapling in the agroforests. The influence of the ecological factors was limited. The main drivers of native forest tree regeneration on farms are the understorey management and the rural extension services that assisted farms obtain state-restricted rights.

La situation de la forêt tropicale dans les pays en développement en général, et en République Démocratique du Congo (RDC) en particulier, est inquiétante. Les émissions de dioxyde de carbone dues au déboisement sont de l’ordre de 1,6 GtCO2e/an, soit 17% des émissions mondiales de « gaz à effet de serre ». Sous l’égide de la Convention-cadre des Nations Unies sur les changements climatiques, le REDD+ a été institué pour lutter contre cette déforestation et la dégradation des forêts. Cette étude examine les différentes opportunités qu’offre ce programme pour l’aménagement écosystémique du couvert forestier de la RDC et les obstacles contextuels à sa mise en oeuvre. Pour la RDC, le REDD+ présente un certain nombre d’opportunités : réduction des émissions liées au déboisement et à la dégradation des forêts; amorce des travaux d’afforestation et de reforestation par une gestion durable des ressources conduisant à la création des emplois et favorisant la croissance des PIB et des exports; accroissement du rendement et maintien d’une plus grande couverture des besoins alimentaires. Le REDD+ peut favoriser la croissance du Produit intérieur brut agricole. Il peut contribuer à l’électrification des ménages et réduire de moitié les dépenses des ménages dépendant de l’exploitation minière et des hydrocarbures et, ainsi, générer des milliers d’emplois en infrastructures. Pour les populations locales et autochtones, il peut contribuer aussi à protéger et à valoriser les cultures liées à la forêt. Mais, face aux pesanteurs d’ordre juridique, politique, social, économique, technologique et culturel caractéristiques de ce pays, ces opportunités risquent d’être amenuisées, sinon annihilées. Étant donné que l’essentiel du déploiement du dispositif du REDD+ se réalisera dans les zones rurales congolaises, l’obstacle majeur reste le droit coutumier. La solution serait d’harmoniser les exigences et finalités du REDD+ non seulement avec le Code forestier de 2002 et ses mesures d’exécution mais aussi avec le droit coutumier auquel les communautés locales et autochtones s’identifient.
The situation of the rainforest in developing countries in general and the Democratic Republic of Congo (DRC) in particular is worrying. Emissions of carbon dioxide from deforestation are about 1.6 GtCO2e/an, or 17% of global emissions of "greenhouse gases". Under the auspices of the UN Framework Convention on Climate Change, REDD+ has been established to fight against the deforestation and degradation of forests. This study examines the different opportunities offered by the program for ecosystem-based management of forest cover in the DRC and contextual barriers to its implementation. For the DRC, REDD+ has a number of opportunities: reducing emissions from deforestation and forest degradation; work begins afforestation and reforestation for sustainable management of resources leading to job creation and promoting the growth of GDP and exports, increased yield and maintaining greater food needs. The REDD+ can promote the growth of the agricultural gross domestic product. It can contribute to the electrification of households and halve spending dependent on mining and oil and thus generate thousands of jobs in infrastructure. For local and indigenous communities, it can also help to protect and promote the cultures associated with the forest. But, faced with the burdens of legal, political, social, economic, technological and cultural characteristics of the country, these opportunities may be diminished, if not annihilated. Given that most of the deployment of the REDD+ will happen in Congolese rural areas, the major obstacle is the customary law. The solution would be to harmonize the requirements and objectives of REDD+ not only with the Forest Code of 2002 and its implementing rules but also with the customary law which local and indigenous communities identify.

Budongo Forest Reserve (BFR) is a flagship reserve for primate conservation due to its abundant chimpanzee (Pan troglodytes) population, and its current management policy for multiple economic, conservation and environmental benefits. The identification and better understanding of the structure and dynamics of the forest/plant community types, patterns of species distribution and quantitative properties of their diversity is important to the conservation and sustainable management of tropical rainforests. This study seeks to contribute to a better understanding of the BFR forest community types, species diversity patterns and environmental correlates, as well as natural regeneration processes (i.e. seedling establishment and sprouting). Data on vegetation and environmental variables were collected using rectangular 50 x 100m (0.5 ha) plots, sub-divided into five equal contiguous (20 x 50 m) 0.1 ha sub-plots. Data on land-use/cover changes, and relevant associated socio-economic parameters were collected through the analysis of multi-temporal satellite imagery and field observations, as well as interviews of local households and key informants. The study revealed significant land-use/cover changes, with the area under sugarcane cultivation increasing over 17-fold, from 690 ha in 1988 to 12729 ha in 2002, with a concomitant loss of about 4680 ha (8.2% loss) of forest/woodland, mainly in the southern part of BFR. These changes are attributed to agricultural expansion, a rapidly increasing human population, exacerbated by large influxes of refugees, lack of alternative sources of income, conflicts of interest and political interference in the management of BFR, and an unclear land tenure system. The need for more land for agricultural expansion and the loss of woodlands (a source of building materials and fuelwood for the local communities) is leading to the invasion of and encroachment on BFR, which threatens plant and wild animal conservation. The study revealed that the vegetation of BFR is formed by a mosaic of plant communities, with the major forest types being; Pseudospondias microcarpa Swamp Forest, Funtumia elastica - Pouteria altissima, Lasiodiscus mildbraedi - Khaya anthotheca and Cynometra alexandri - Rinorea ilicifolia forest communities. Canonical correspondence analysis (CCA) indicated that soil nutrients (Si, Ca, N, Fe and Li) and anthropogenic disturbances are the main factors controlling forest community patterns. The variances explained as a proportion of total inertia were relatively high (0.53 and 0.56 for basal area and abundance, respectively), showing how well the measured variables explained species composition. These plant communities differed significantly in terms of woody species diversity and richness; being highest in the Pseudospondias microcarpa swamp and lowest in the Cynometra alexandri-Rinorea ilicifolia forest. However, about 48 species were shared between the forest community types. A total of 269 species representing 171 genera and 51 families was recorded. Fisher’s alpha-diversity ranged 4.45-30.59 and 3.07-29.7 for stem diameters ≥2.0 cm and ≥10 cm, respectively, being significantly higher for stem diameters ≥2.0 cm. The use of stem diameters ≥2.0 cm unveiled 53 more species (19.7%), with only 216 species recorded for the standard ≥10 cm dbh minimum size usually applied in tropical forests. A SHE analysis also showed greater richness (ln(S)) and H diversity for the >2.0 cm than the ≥10cm stem diameters. Hence, the study reaffirmed that the use of 10 cm as a minimum dbh in woody plant diversity studies in forests, where many tree species rarely exceed 10 cm stem diameter, is highly likely to underestimate diversity and richness, potentially biasing the understanding of diversity patterns. The most speciose families were Euphorbiaceae, Fabaceae, Rubiaceae, Moraceae, Meliaceae, Rutaceae, Annonaceae, and Flacourtiaceae, accounting for 147 species. Families with the highest Familial Importance values (FIV) were; Fabaceae (17.5), followed by Euphorbiaceae (16.3), and Ulmaceae (8.35). The BFR exhibits characteristics intermediate between log-normal and log-series species-abundance distributions, indicating a community with a small number of abundant species and a relatively large proportion of rare species. Both Whittaker’s (βw) and the Morisita-Horn Index measures of β-diversity consistently showed higher β-diversity for logged and arboricide treated areas, followed by logged only, and then nature reserve historical management practice types. β-diversity was relatively high at the total forest community scale, but lower for stem diameter ≥2.0 cm than ≥10.0 cm data. Environmental variables significantly explained 66.5% and 61.9% of the variance in species composition for stem diameter ≥2.0 cm and ≥10.0 cm data, respectively. Hence, the variation in species composition of BFR is characterised by significant spatial patterns, and the patterns in β-diversity are to a great extent associated with environmental heterogeneity (i.e. soil nutrients, topographic and light gradients) and anthropogenic disturbances. Investigation of natural regeneration showed that sprouting is generally common among the woody species, with both canopy and sub-canopy trees sprouting prolifically. Of the 122 species affected by ii harvesting, and tree and branch fall disturbances, 199 (97.5%) from 31 families sprouted from the cut stumps, with only Caloncoba crepiniana (De Wild. & Th.Dur.) Gilg exhibiting both stem and root sprouting. Stump basal diameter, height, bark-thickness, and height of stump above the ground at which the first sprout emerged, were significant predictors of sprouting ability among individuals. Number of sprouts/stump differed significantly among families, species, and stump size-classes. Of the 241 seedling species, representing 46 families, about 30.3% were rare (only 2-10 individuals); while 12% were very rare (only 1 individual each). Cynometra alexandri C.H. Wright and Lasiodiscus mildbraedii Engl. were the most abundant seedlings and also among the most widely distributed species in the forest. Analysis of similarity (ANOSIM) revealed significant differences in seedling composition between transects, but not between topographic positions or historical management practice types. Canonical Correspondence Analysis (CCA) showed that the measured environmental variables significantly explained 59.4% of the variance in seedling species distributions, with the three most important variables being organic matter, titanium and leaf area index (LAI; an indicator of light availability below the canopy). Hence, the important mechanisms influencing regeneration via seedlings in BFR operate through the soil system, and the ground and canopy vegetation characteristics. Nine of the 15 intensively studied multiple-use species, namely L. mildbraedii, Celtis Mildbraedii Engl., Pouteria altissima (A. Chiev.) Aubrev. & Pellegr., Chrysophyllum albidum G. Don., C. alexandri, Diospyros abyssinica (Hiern) F. White, Funtumia elastica (Preuss) Stapf., Chrysophyllum perpulchrum Hutch. & Dalz, and Antiaris toxicaria (Pers.) Lesch. had highly negative size-class distribution (SCD) slopes and substantial seedling regeneration. While Alstonia boonei De Wild. and Cordia millenii Bak. had weakly negative SCD slopes and pulsed or sporadic regeneration patterns. The wide distribution of seedlings for a variety of species, and with most of the intensively studied species having population structures showing healthy regeneration patterns, suggests that BFR is currently experiencing a continuous regeneration phase. In conclusion, the gradients in the vegetation of BFR are a reflection not only of site conditions as shown by the edaphic and abiotic factors, but also the history of human interventions.