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Change in the woody floristic composition, diversity and structure from protected to unprotected savannahs in Pendjari Biosphere Reserve (Benin, West Africa)

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Abstract

Savannahs are widespread vegetation type in Sudanian zone of Africa. As protected areas are often assumed to be the best way to conserve biodiversity, we assessed the effectiveness of the Pendjari Biosphere Reserve in Benin, for maintaining savannah woody species composition, diversity and structure. Square plots of 900 m2 were randomly established in protected and surrounding unprotected savannahs, and all woody species (dbh � 1 cm) were recorded and identified. Species composition, Importance Value Index, densities, basal area and diversity indexes were assessed in relation to conservation status. The results showed that DCA based on presence/absence species data did not separate clearly protected savannahs from unprotected ones. However, some species were prominent in unprotected savannahs while others showed the same scheme in protected ones. Diversity indexes indicated a good distribution of species in the two savannah types. The woody density showed a higher value in protected than unprotected savannah at shrub layer level. The basal area was significantly higher in the protected savannah than unprotected one at the two woody layer levels. It can be concluded that biodiversity conservation in surrounding unprotected areas should be of great importance to increase biodiversity conservation by protected area whether specific actions were implemented.

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... The authors reported very rare saplings of A. africana with recruitment and growth difficulties in natural stands. The low regeneration density observed in the Sudanian zone (even in the protected area) suggests that, protection would not be always a sufficient action to conserve some threatened tree species; other factors like climate pejoration and occurrence of potential bush fires may also compromise the viability of the threatened tree species (Biaou 2009, Nacoulma et al. 2011, Ouédraogo and Thiombiano 2012, Houehanou et al. 2013b). ...
... Moreover, the highest density of regeneration was observed in this climatic zone. Thus, the species is supposed to be more adapted to the climatic conditions of the Guinean zone (Houehanou et al. 2013b) even though it has been reported as being mostly valued in the Sudanian regions (Adomou et al. 2009, Nacoulma et al. 2011. In fact, Sudanian and Sudano-Guinean zones are still the potential areas for the seasonal movements of herds. ...
... In other words, this variation in species richness of A. africana habitat, is not indicative of the trend in plant diversity of each bioclimatic zone. The observed trend where diversity parameters were high in A. africana natural stands of the Sahelo-Sudanian, Sudanian and Sudano-Guinean zones and relatively low in the Guinean one has also been reported by previous studies (Ouédraogo 2006, Bonou et al. 2009, Houéto et al. 2012, Houehanou et al. 2013b). This may be explained by the fact that the environments in Sudanian and Sahelian areas are more heterogeneous, and may contain more niches that can support more species. ...
... These activities result in considerable loss of biodiversity, degradation of timber and non-timber resources as well as disruption of the ecological and biological complexities in the forests. Consequently, plant species composition and abundance in disturbed and fragmented tropical forests have increasingly become important economically, socially as well as for biodiversity conservation, especially with the alarming rate at which original primary forests are disappearing (Makana and Thomas 2006;Oke and Odebiyi 2007;Houehanou et al. 2013). ...
... The ability of such tropical forest ecosystems to recover is limited as high and excessive logging has negative effects on the availability of quality seed germplasm for natural regeneration (Vordzogbe et al. 2005;Makana and Thomas 2006). Therefore, information on floristic composition and diversity as well as tree volume are essential for understanding disturbed tropical forest ecosystem dynamics Houehanou et al. 2013). Tree diversity is particularly fundamental to total tropical rainforest biodiversity, as trees provide habitat structure and resources for other flora and fauna species. ...
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Floristic composition, plant species diversity, tree canopy structure and regeneration were assessed in degraded tropical humid rainforest in Nigeria using a systematic line transect sampling technique for plot demarcation. All plants in a plot were identified and classified into families while the diameters and heights of trees with diameter at breast height (Dbh) >10cm were measured. Tree basal area, total volume, density, dominance, frequency, Importance Value Index (IVI), Equitability Indices (EH) were then computed. A species-area curve was used to determine the relationship between forest area and number of species encountered while tree height was used to assess canopy structure. Eighty-three plant species belonging to 78 genera in 39 families were identified. Trees were the predominant plant form with 46 species (172 trees ha-1) while 7 shrubs, 15 lianas, 13 herbs, 1 grass and 1 fern species were recorded. Tree basal area and total volume were 10.29±0.88 m2 ha-1 and 22.43±1.85 m3 ha-1 respectively. The tallest tree height (35m) was recorded for Terminalia superba while the shortest (9.3m) was Ficus mucuso. The three most abundant families were Fabaceae (15.9%), Sterculiaceae (9.8%) and Moraceae (7.3%) while the most dominant species were Trema orientalis (4%), Terminalia superba (4%) and Mansonia altissima (6.29%) with IVI of 14.92%, 14.79% and 13.73%, respectively. A high level of tree species diversity was observed with H1 and EH of 3.65 and 0.97 respectively. There were 29 tree species found to be naturally regenerating (seedlings saplings) and no species was found in the emergent layer. Despite the high level of anthropogenic interference in the ecological processes, Akure–Ofosu forest reserve remains highly diverse in plant species composition and it has great potential for restoration if properly managed with silvicultural interventions such as seed supplementation and/or enrichment planting which would encourage the rapid return of the complex forest conditions. Keywords: Natural regeneration, forest restoration, species-area curve, Akure-Ofosu Forest Reserve.
... The role of protected areas in the prevention of extinction of species has been much debated (Bruner et al., 2001). Several studies focused on the effectiveness of the protected areas to ensure the representativeness and persistence of biodiversity components (Defries et al., 2005;Wittemyer et al., 2008;Houéhanou et al., 2011Houéhanou et al., , 2012Houéhanou et al., , 2013. Some of the studies (Djossa et al., 2008;Gouwakinnou et al., 2009;Schumann From the demographic explosion, correspondingly strong land modification was observed in West Africa (Wittig et al., 2007;Wittemyer et al., 2008). ...
... In addition, the Importance Value Index (IVI) was used to measure how dominant an orchid species is in a given zone according to the conservation status (protected and unprotected) of the area (Houéhanou et al., 2012). The calculation of IVI for orchid species was based on Relative Density (RD) and Relative Frequency (RF). ...
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The effectiveness of protected areas to guarantee future conservation of several plant species remains questionable. This study was carried out in the Biosphere Reserve of Pendjari (BRP) and surrounding unprotected areas to assess the efficiency of the reserve to conserve orchids. A total of 90 plots (52 in protected areas; 38 in unprotected areas) were sampled. The recorded data include: orchid species, number of individuals per species, the height and diameter at breast height of host trees. Diversity indices were used to assess the orchid diversity in the protected and unprotected areas. Preferred habitat conditions of orchid species were investigated using Constrained Correspondence Analysis. An independent t-test and two-way analysis of variance were performed to assess an existing combined effect of vegetation type and the conservation status on the density of orchid species. The Importance Value Index (IVI) was used to measure how dominant an orchid species is in a given zone according to the conservation status of the zone. Only three epiphytic orchids (Calyptrochilum christyanum, Cyrtorchis arcuata and Plectrelminthus caudatus) were recorded and all in gallery forest of unprotected areas. Indeed, 67% and 58% of the orchid species were only recorded in unprotected areas and in gallery forest, respectively. There was no significant difference between the density of all recorded orchids in protected and unprotected areas. The conservation status of the studied zone had a significant effect on the densities of Nervilia kotschyi and Eulophia guineensis (p < 0.0001). The highest IVI of N. kostchyi was observed in the protected area and of E. guineensis was in the unprotected area. This first effort to compile a reference list of the orchid species of the BRP showed that some orchid species were well represented within the protected area, but all of the epiphytic orchids were recorded from unprotected areas. A representative gap can be assumed to exist for most epiphytic orchids only recorded in the gallery forests of unprotected areas. Our results highlighted the need to redefine protective management strategies for orchid species in the BRP.
... Protected areas (PAs) have been suggested globally as a cornerstone for biodiversity conservation and management (Clark et al. 2013;Houehanou et al. 2012). The PAs maintain and promote the population of native species, composition of communities, conserve the genetic diversity of all resident species and permits the sustainable flow of natural goods and services to fulfil the requirements of the local residents . ...
... In contrast to intermediate disturbance hypothesis of Connell (1978) and Huston (1979), in our study the alpha diversity (Shannon-Wiener index) and its components (species richness and equability) for adults and seedlings life cycle stages declined consistently along the disturbance gradient. This is in conformity with other dry tropical forests studies within and outside the PAs (Chittibabu & Parthasarathy 2000;Clark et al. 2013;Htun et al. 2011;Houehanou et al. 2012;Sagar et al. 2003;Sagar & Singh 2004. The K-dominance curves for adults and seedlings also revealed maximum diversity at least disturbed Bandha site and lowest at highly disturbed Bhoramdeo site. ...
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Protected areas (PAs) are suggested as boon for biodiversity because they preserve genetic diversity, species populations and maintain ecosystem sustainability. In the Bhoramdeo wildlife sanctuary of central India, four locations differing in anthropogenic disturbances were selected. At each location, three homogeneous plots were marked to study tree species composition, diversity and regeneration against anthropogenic pressure. Within each plot 10 quadrats of 10 × 10 m in size were established and diameter of all stems of each species for each life stage was determined. From the entire 1.2 ha areas total 65 species, 273890 stems and 23.8 m2 ha−1 basal area (≥ 30 cm height) were recorded. Anthropogenic disturbances changed species composition, limited regeneration and reduced species diversity. Bray-Curtis analysis of each life cycle stage for each location suggested temporal dynamism in species composition. Study showed negative relationship between seedlings species diversity and conservation focussed species populations. The negative relationships of pole’s species number and stems with averaged tree canopy size, and disturbance scores with seedling’s species number, Shannon index, and that of pole’s stem suggested for selective harvesting of old age trees in addition to stop the practice of harvesting of juveniles for sustainable management of protected forests of dry tropics.
... When the demand for forest ecosystem services supersedes it carrying capacity due to intensive biotic disturbance and the collection of non-timber products, its biodiversity will decline at a rate faster than it can regenerate. According to Houehanou et al. [68], bushfires have proven to have adverse effects on trees species and hence affecting its density, especially in lower regions. Additionally, Pereki et al. [63] stated ...
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Riparian forests inventory is essential in understanding the floristic biodiversity and provides necessary information on the growth trend and status of plant diversity along forests ecosystem especially the riparian forests. This study was undertaken to assess the species diversity, growth status and bio-volume of Taia riparian forest for community-based conservation intervention. In this study, we enumerated 602 individual trees, which comprised 49 species that belong to 37 genera in 25 families. In total, [14] rectangular plots of dimension 20 x 50m 2 were demarcated. All trees species within the sampled plots having Diameter at Breast Height [Dbh] ≥ 7cm were identified and height measured using the Haga Altimeter, girth and measuring tape to determine the growth status. The result shows that 83% of the trees enumerated have [Dbh] that range from 7-30cm while 17% had [Dbh] greater than 30cm. Funtumia africana and Trichilia heudilotii were the dominant species in almost all aspect in the study area. Meliaceae, Apocyanaceae and Mimosaceae were the dominant families with the highest species. The Shannon diversity index was 3.094 while the Simpson and Evenness diversity was 0.9303, 0.4502, respectively. Other diversity indices estimated were Margalef 7.544, Equitability 0.7949, Fisher_alpha 12.77. The overall bio-volume was 283.05m 3 with a total basal cover of 12,54m2. Height and [Dbh] were not significantly correlated with the bio-volume. Biotic pressure such as fuelwood collection, unsustainable charcoal production, pole harvesting, bushfires, and other traditional and cultural functions contributes greatly to the exploitation of the riparian forest. Therefore, urgent strategic conservation and protection measures should be adopted to prevent further degradation of forest ecosystems along river banks in the District and other ecologies in Sierra Leone.
... This is due to low rainfall and high temperatures which translate the aridity of sudanese climate. This floristic trend has been reported by [39,40] respectively in Burkina and in Benin. This trend is characteristic of African sudanian savannas. ...
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Aims: As a contribution to the sustainable management of protected areas in Togo, this study aims to analyze the impact of anthropogenic activities on plant communities in the wildlife reserve of Oti-Mandouri (North-Togo). Study Design: The study area is located in the Sudanian zone, in northeast Togo. Place and Duration of Study: The field work was carried out during April and June 2009, whilst processing data was done at Lab From July to October 2009. Methodology: Total height and stem diameter at breast height (dbh) greater than 10 cm of all trees species were measured in 126 plots. In each plot, ecological parameters were recorded and the seedling and suckers (dbh<10cm) of species were counted. Results: 116 woody species with dbh greater than 10 cm belonging to 33 families and 84 genera were listed. Presence/absence data of the overall species recorded in each plot was subjected to multidimensional scaling and results showed 4 types of woody vegetation: shrub savannas, tree savannas, wooded savannas and gallery forest. The most common families were Rubiaceae (14.28%), Mimosaceae (13.26%) and Combretaceae (11.22%). Species such as Combretum glutinosum (48.68%), Mitragyna inermis (36.84%), Acacia polyacantha (35.52%) and Piliostigma thonningii (35.52%) were relatively more frequent, but this potential floristic resource was almost threatened by human activities such as farming, grazing, burning, and tree cutting. The structure adjusted by 3-parameter Weibull showed reverse “J” shape for class diameter distribution with shape parameter varies between 1 and 3.6 showing a predominance of individuals with small diameter within the overall study area. Conclusion: The results showed that this protected area is subjected to much degradation, and its conservation is important in the process of biodiversity conservation varices grades.
... , 2014). Human-induced disturbance (such as mining, timber extraction, etc.) and livestock grazing also cause changes in species number, tree density and basal area (Rao et al., 1990). Unrestricted and open accessibility may cause enhanced utilization of the forest resource and this may eventually lead to a species-poor state (Murali et al., 1996). Houehanou et al. (2012), while studying changes in the woody floristic composition and diversity in the savannahs of West Africa concluded that the disturbances affect on woody diversity at tree layer level and such effect should be mostly linked to the firewood use that selects adult tree individuals of some woody species and consequently decreases woody spec ...
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Species richness, diversity and distribution pattern of tree species were studied along a disturbance gradient in three mixed broad leaved forests. The forests were selected on the basis of varying disturbance intensities and were categorized into highly disturbed (HD), moderately disturbed (MD) and least disturbed (LD). A total of 34 tree species (belonging to 30 genera and 21 families) were reported along the disturbance gradient. Both tree species richness and diversity markedly declined along the disturbance gradient from LD to HD forests. Maximum species richness (20) was reported from LD while minimum (11) from HD forest. Shannon Wiener index (2.30-3.34), Margalef’s index (2.59-4.11), Menheink’s index (1.60-1.99) were maximum in LD and minimum in HD forests. Species richness and diversity indices showed significant negative relation with disturbance. Diversity-dominance (d-d) curve showed high equitability in LD forest while high dominance in MD and HD forests. More than 90% of tree species showed contagious distribution that is the most common distribution pattern in nature but it did not show any definite trend along the disturbance gradient. Low maturity value and contagious distribution of species denote the early successional status of the studied forests. The present study reveals that the anthropogenic disturbance causes disruption of forest structure and changes species composition which ultimately leads to reduction of tree species richness and diversity which is a major forest component.
... This is due to low rainfall and high temperatures which translate the aridity of sudanese climate. This floristic trend has been reported by [39,40] respectively in Burkina and in Benin. This trend is characteristic of African sudanian savannas. ...
... We identified ten species with a high ecological importance (IVI ≥ 10 %) in mature forest vegetation. Our set of key species corresponds well with previous findings from protected North-Sudanian savannas; all key species (except Crossopteryx febrifuga) were frequently found to have IVI values ≥ 10 % (Ouédraogo et al., 2009;Gnoumou et al., 2011;Houehanou et al., 2013b). C. febrifuga populations tend to have a clumped spatial dispersion and might for this reason not be well-represented in other studies. ...
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Increasing land-use pressure threatens the persistence of tree populations in West Africa’s savannas. We do not fully understand yet why tree species respond differently to human disturbances, hampering the design of appropriate management strategies. To identify typical response pathways, we compared tree populations in three land-use types with increasing levels of human disturbance (protected forest, fallow and field). We analyzed size-class distributions (SCDs) of species and plant functional types, and compared the performance of juvenile and adult age-classes. Biomass was derived from biometric measurements via allometric equations. Higher land-use pressure increased juvenile proportions of plant functional types, but divergent responses were found for species: Juvenile proportions on fields were either very low (0%) or, in most cases, very high (>96%), leading to SCDs with significant negative slopes. While negative slopes are commonly interpreted as indicating populations with sufficient recruitment, they could also indicate growth suppression, particularly if size-classes are missing between juveniles and adults. This ‘juveniles get trapped’ pathway is well-recognized for near-natural savannas with a high incidence of fire (‘fire trap’) or wild browsers (‘browse trap’), and is attributed to a high resprouting ability of trees. As resprouting constitutes a pre-adaptation to human disturbances, the trap concept should be extended accordingly. Species dominating in highly disturbed environments are either characterized by trait combinations allowing them to persist in a ‘human disturbance trap’, or they are actively protected. Our results advocate for designing management strategies that take into account how species’ age-classes respond to disturbances. As the escape of juveniles to mature vegetation is a main demographic bottleneck for most Sudanian savanna species, it is essential to create escape opportunities.
... Indeed, human activities have disturbed savanna ecosystems for a long time (Lykke, 1998), as savannas are a resource for food, medicine, timber and livestock breeding (Bellefontaine, 2000;Twine et al., 2003). Moreover, savanna structure has a large impact on biodiversity, both for plants (Houehanou et al., 2012) and animals (Tews et al., 2004), and for species conservation. Human pressure is known to have an impact on savanna habitats (e.g. ...
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Understanding the factors that determine vegetation nature and dynamics in Central Africa is an important issue given climatic changes and increasing human pressure. Forest and savanna are often considered as two alternative stable and highly contrasted states, driven by complex interactions between climate, soil and disturbances. The current relationships between tree cover and its determinants (annual water deficit, fire frequency, population density, intensity of land use and soil type) were characterized using remote sensing data and a statistical model. It has been shown that there is not one, but several savanna stable states. For savanna states of low tree cover (≤ 35%), it is mainly the soil type and the annual water deficit which determine their presence and the transition from one to another. The most wooded savannas (> 35%) and the forests seem to be the most sensitive to anthropogenic disturbances. However, this statistical model can only describe the contemporary relationships between vegetation structure and its determinants. Conversely, studying environmental bio-proxies preserved in natural archives, which constitutes the paleo-ecological approach, enables reconstructing long-term vegetation, disturbances and some climatic features, in order to obtain a dynamic view of their relationships. Paleo-sequences from three lakes, currently located in a forest, in a savanna-forest mosaic, and in a savanna, were investigated. On the one hand bio-proxies from recent lake sediments were compared to satellite images, and on the another hand a statistical model between bio-proxies from modern soils and vegetation surveys was calibrated. The results of these studies enabled to better understand the information carried by phytoliths and charcoals, and therefore to better estimate vegetation structure and fire history. Moreover, they emphasize the importance of precisely identifying taphonomic processes in order to accurately reconstruct paleo-environments. The preliminary results of a lacustrine paleo-sequence covering the last 3000 years are presented in discussion. Although the environment around the lake has remained a savanna, vegetation structure has undergone significant changes due to both climate change and modifications in fire regimes. Moreover, it seems that these structural changes were not gradual but happened abruptly, as it happens currently along the climatic gradient. This work therefore predicts a critical response of tropical biomes to global changes.
... ll (1987). Human-induced disturbance (such as mining, timber extraction, etc.) and livestock grazing also cause changes in species number, tree density and basal area (Rao et al. 1990). Unrestricted and open accessibility may cause enhanced utilization of the forest resource and this may eventually lead to a species-poor state (Murali et al. 1996). Houehanou et al. (2012), while studying changes in the woody floristic composition and diversity in the savannahs of West Africa concluded that the disturbances affect on woody diversity at tree layer level and such effect should be mostly linked to the firewood use that selects adult tree individuals of some woody species and consequently decreases woody spec ...
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The present study assesses anthropogenic disturbances and their impacts on the vegetation in Western Himalaya, India on the basis of various disturbance parameters such as density, Total Basal Cover (TBC) of cut stumps, lopping percentage and grazing intensities. On the basis of canopy cover and frequency of disturbances (%), the studied forests were divided into highly disturbed (HD), moderately disturbed (MD) and least disturbed (LD) categories. The HD forests had the lowest canopy cover, lowest density and lowest TBC and the LD had the highest canopy cover, highest density and highest TBC. The MD forests occupied the intermediate position with respect to these parameters. Species richness was least in HD forests, highest in one of the MD forests while LD forest occupied an intermediate position. The percentage of regenerating species was lowest (54%) in HD and highest (72%) in MD. The density of seedlings and saplings was higher in one of the MD forests as compared to HD and LD. We concluded that the moderate disturbances do not affect the vegetation adversely; however the increased degree of disturbance causes loss in plant diversity; affects regeneration and changes community characteristics. Construction of hydroelectric projects at various places in the study area was found to be one of the most important sources of anthropogenic disturbances in addition to the routine anthropogenic disturbances like grazing, fuelwood collection and fodder extraction. If all proposed dams in the Indian Himalaya are constructed combined with weak national environmental impact assessment and implementation, it will result in a significant loss of species. Therefore, various agents of disturbances should be evaluated in cumulative manner and any developmental activities such as hydropower projects, which trigger various natural and anthropogenic disturbances, should be combined with proper cumulative environmental impact assessment and effective implementation to minimise the anticipated loss of vegetation. © 2016, Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg.
... Afzelia africana et Khaya senegalensis sont deux de ces espèces menacées, déjà inscrites sur la Liste rouge de l'UICN alors qu'elles semblent même en danger critique d'extinction au Bénin (Adomou et al., 2006). Au-delà de ces deux espèces assez connues pour leur utilité comme source de fourrage pour le bétail et comme bois d'oeuvre très prisé dans le commerce international du bois, d'autres espèces comme Daniellia oliveri et Anogeissus leiocarpa se révèlent très vulnérables aux pressions anthropiques et sont de plus en plus rares (Houehanou et al., 2013). ...
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The aim of this study was to assess the effectiveness of protected areas in Benin for the conservation of favourable and priority habitats for the following tree species of socio-economic importance: Afzelia africana, Anogeissus leiocarpa, Burkea africana, Daniellia oliveri, Detarium microcarpum, Prosopis africana and Khaya senegalensis. We combined maximum entropy (Maxent) techniques with GIS to predict potentially favourable areas for cultivating and conserving these species. Zonation software was used to model priority habitats. Data points where the species were present were collected and linked to bioclimatic variables derived from monthly temperature and rainfall figures from the Africlim database and to edaphic (soil) variables. In term of environmental determinism, the most favourable areas were predicted by bioclimatic variables such as mean diurnal temperature range (Bio2), mean annual rainfall (Bio12), potential evapotranspiration (PET) and a biophysical ground variable. The most favourable protected areas for the seven tree species extended northwards from the Ketou listed forest (7 degrees 43'N) in the Guinean zone, from the Agoua listed forest (8 degrees 30'N) in the Sudano-Guinean zone and from the Pendjari National Park area (10 degrees 35'N) in the Sudanian zone. Gap analysis of habitat conservation showed that the protected area network was effective in the Sudanian zone (9 degrees 75'-12 degrees 27'N), minimally effective in the Guinean zone (6 degrees 50'-7 degrees 40'N) and not effective at all in the Sudano-Guinean zone.
... Afzelia africana et Khaya senegalensis sont deux de ces espèces menacées, déjà inscrites sur la Liste rouge de l'UICN alors qu'elles semblent même en danger critique d'extinction au Bénin (Adomou et al., 2006). Au-delà de ces deux espèces assez connues pour leur utilité comme source de fourrage pour le bétail et comme bois d'oeuvre très prisé dans le commerce international du bois, d'autres espèces comme Daniellia oliveri et Anogeissus leiocarpa se révèlent très vulnérables aux pressions anthropiques et sont de plus en plus rares (Houehanou et al., 2012). ...
... Forest ecosystems and wildlife habitats are currently under high human pressure and climate change impacts in West Africa [10][11][12], particularly in Togo [13]. In this country, forest cover is being highly reduced with serious impacts on ecosystem resilience to climate change [14]. ...
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Biodiversity conservation planning is highly important in the current context of global change. Biodiversity conservation can be achieved by understanding changes in land use at the landscape scale. Such understanding is needed to reverse the unprecedented pressure on natural resources that has been reported by many studies conducted on biodiversity conservation within the Oti-Keran-Mandouri protected areas. Land cover maps reflecting different dates (1987, 2000, and 2013) and depicting different management systems, with overall accuracy ranging from 73% to 79%, were analyzed to understand the processes that lead to habitat degradation within these protected areas. The nature of change, within a given land cover class, was determined by comparing land cover maps on different dates using a decision tree algorithm that compares the number of patches, their areas, and their perimeters at different time periods (T1 and T2). Specifically, two time-periods were considered for this analysis: 1987-2000 and 2000-2013. Croplands and settlements increased at an average of 108.13% and 5.45%, respectively, from 1987 to 2000. From 2000 to 2013, croplands gained from all other land categories and continued to increase at a rate of 11.77% per year, whereas forests and savannas decreased at an annual average rate by 5.79% and 2.32%, respectively. The dominant processes of habitat change from 1987 to 2000 were the creation of forests, dissection of savannas, attrition of wetlands, and creation of croplands. Meanwhile, from 2000 to 2013, there was attrition of forests, as well as attrition of savannas, dissection of wetlands, and aggregation of croplands. In general, from 1987 to 2013, natural habitats regressed and were replaced by croplands; forests, savannas, and wetlands decreased at an average annual percentage 5.74%, 3.94%, and 2.02%, respectively, whereas croplands increased at an average annual rate of 285.39% of their own area. Aggregation, attrition, dissection, and creation were the main habitat change processes identified for the overall period from 1987 to 2013. There was habitat loss in forests and savannas and habitat fragmentation in wetland due to attrition and dissection, respectively. Identifying and understanding habitat change processes would enable the taking of appropriate biodiversity conservation actions.
... This is due to low rainfall and high temperatures which translate the aridity of sudanese climate. This floristic trend has been reported by [39,40] respectively in Burkina and in Benin. This trend is characteristic of African sudanian savannas. ...
... The popularity of a tree species defines the attraction of a species for its usability by local people, and the versatility describes the attraction of the species for various purposes. An importance value index combines the relative density, the relative dominance and the relative frequency of a species in a given area and is also widely used to assess the local ecological availability of a tree species (Houehanou et al. 2013;Lucena et al. 2012;Reitsma 1988). ...
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Quantitative ethnobotany researches can contribute much to guide biodiversity conservation, especially in developing countries. Our study presents a step-by-step approach to identify priority species for local conservation of useful woody species. The presented approach includes (1) an investigation of the popularity and versatility of woody species in the local people, (2) an estimation of the ecological availability of useful tree species in the forest and (3) identification of local priority species for conservation. We focused the study on the Wari-Maro forest reserve in the Sudanian zone of Benin as an example to implement such approach and identify useful priority species for sustainable conservation and management strategies development. Ethnobotanical surveys were conducted with people in surrounding villages of the forest composed by different sociocultural groups. Floristic vegetation surveys were performed within the forest to assess the local ecological availability of used woody species. A principal component analysis was performed to analyze the versatility, the popularity and the ecological availability of species. Spearman’s correlation test was used to assess relation between variables. In total, 79 woody species were reported for seven main types of uses: technology, construction, medicinal, veterinary, food, forage and energy. Among them, 35 were most popular and versatile, and 3 were characterized as priorities for conservation especially regarding their less availability and more versatility. We discussed the used approach by the underlining importance of integrating wood uses or multiples uses in conservation priorities setting and conservation decision-making of useful woody tree species.
... Pourtant certaines espèces ligneuses fourragères comme Afzelia africana et Khaya senegalensis sont menacées et déjà inscrites sur la Liste Rouge de l'Union Internationale pour la Conservation de la Nature (UICN) alors qu'elles semblent même en danger critique d'extinction dans le pays [11]. Ces espèces ligneuses fourragères sont très vulnérables aux pressions anthropiques et deviennent de plus en plus rares [12,13]. Plusieurs travaux ont montré l'importance des ligneux fourragers sur l'alimentation des ruminants [14 -16]. ...
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... Elsewhere, this study has found that in Southern Benin, where the two target species were more abundant, pineapple production was the main destroying factor; thus, because it has been shown that human-managed ecosystems could contribute to conservation of biodiversity (Houehanou et al. 2013), the agronomic requirement and trade scope of pineapple production in Benin run counter. In fact, the production of other crops such as maize seems to be less destructive because they are compatible with agroforestry. ...
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... Forest ecosystems and wildlife habitats are currently under high human pressure and climate change impacts in West Africa [10][11][12], particularly in Togo [13]. In this country, forest cover is being highly reduced with serious impacts on ecosystem resilience to climate change [14]. ...
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Mature tropical forests at agricultural frontiers are of global conservation concern as the leading edge of global deforestation. In the Ituri Forest of DRC, as in other tropical forest areas, road creation associated with selective logging results in spontaneous human colonization, leading to the clearing of mature forest for agricultural purposes. Following 1–3 years of cultivation, farmlands are left fallow for periods that may exceed 20 years, resulting in extensive secondary forest areas impacted by both selective logging and swidden agriculture. In this study, we assessed forest structure, tree species composition and diversity and the regeneration of timber trees in secondary forest stands (5–10 and ∼40 years old), selectively logged forest stands, and undisturbed forests at two sites in the Ituri region. Stem density was lower in old secondary forests (∼40 years old) than in either young secondary or mature forests. Overall tree diversity did not significantly differ between forest types, but the diversity of trees ≥10 cm dbh was substantially lower in young secondary forest stands than in old secondary or mature forests. The species composition of secondary forests differed from that of mature forests, with the dominant Caesalpinoid legume species of mature forests poorly represented in secondary forests. However, in spite of prior logging, the regeneration of high value timber trees such as African mahoganies (Khaya anthotheca and Entandrophragma spp.) was at least 10 times greater in young secondary forests than in mature forests. We argue that, if properly managed and protected, secondary forests, even those impacted by both selective logging and small-scale shifting agriculture, may have high potential conservation and economic value.
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Tree species richness, tree density, basal area, population structure and distribution pattern were investigated in undisturbed, mildly disturbed, moderately disturbed and highly disturbed stands of tropical wet evergreen forests of Arunachal Pradesh. The forest stands were selected based on the disturbance index (the basal area of the cut trees measured at ground level expressed as a fraction of the total basal area of all trees including felled ones): (i) undisturbed stand (0% disturbance index), (ii) mildly disturbed (20% disturbance index), (iii) moderately disturbed (40% disturbance index), and (iv) highly disturbed stand (70% disturbance index). Tree species richness varied along the disturbance gradient in different stands. The mildly disturbed stand showed the highest species richness (54 of 51 genera). Species richness was lowest (16 of 16 genera) in the highly disturbed stand. In the undisturbed stand, 47 species of 42 genera were recorded while in the moderately disturbed stand 42 species of 36 genera were found. The Shannon–Wiener diversity index for tree species ranged from 0.7 to 2.02 in all the stands. The highest tree diversity was recorded in the undisturbed stand and the lowest in the highly disturbed stand. The stands differed with respect to the tree species composition at the family and generic level. Fagaceae, Dipterocarpaceae and Clusiaceae dominated over other families and contributed 53% in the undisturbed, 51% in the mildly disturbed, 42% in the moderately disturbed and 49% in the highly disturbed forest stands to the total density of the respective stand. Stand density was highest (5452 stems ha-1) in the undisturbed stand, followed by the mildly disturbed stand (5014), intermediate (3656) in the moderately disturbed stand and lowest (338) in the highly disturbed stand. Dominance, calculated as the importance value index of different species, varied greatly across the stands. The highest stand density and species richness were represented in the medium girth class (51–110 cm) in all the stands. In the undisturbed stand, the highest density was found in the 111–140 cm girth class, while in the mildly disturbed stand the 51–80 cm girth range recorded the highest density. About 55, 68 and 52% species were found to be regenerating in the undisturbed, mildly disturbed and moderately disturbed stands, respectively. No regeneration was recorded in the highly disturbed stand. Variation in species richness, distribution pattern and regeneration potential is related to human interference and the need for forest conservation is emphasized.
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The present study focused on the analysis of the structure of the Anogeissus leiocarpa dominated natural stands in the Wari-Maro forest reserve which are under high and minimal anthropogenic pressures. These stands were considered for forest inventories after carrying out a random sampling scheme of 40 sample units of 30 m × 50 m. In each level pressure stand, the dbh and tree-height of identified tree-species were measured in each plot. Data analyses were based on the computation of structural parameters, establishment of diameter and height distributions and the floristic composition of the two types of stands. Results obtained showed higher values for the overall basal area (9.78 m2 ha-1), mean height (22.37 m) and mean diameter (36.92 cm) for A. leiocarpa in low-pressure stands. In high-pressure stands, some species like Afzelia africana had lower Importance Value Index and the frequency of A. leiocarpa trees in the successive diameter classes dropped rapidly and the value of the logarithmic slope of the height-diameter relationship was lower (9.77) indicating a lanky shape. Results obtained suggest that effective conservation is needed for A. leiocarpa stands under high pressure by limiting human interference and developing appropriate strategy for restoration purposes. © 2009 The Authors. Journal compilation
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It is not simple to predict how environmental changes may impact tropical forest species diversity. Published hypotheses are almost invariably too incomplete, too poorly specified and too dependent upon unrealistic assumptions to be useful. Ecologists have sought theoretical simplicity, and while this has provided many elegant abstract concepts, it has hindered the attainment of more practical goals. The problem is not how to judge the individual hypotheses and arguments, but rather how to build upon and combine the many hard-won facts and principles into an integrated science.
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Mature tropical forests at agricultural frontiers are of global conservation concern as the leading edge of global deforestation. In the Ituri Forest of DRC, as in other tropical forest areas, road creation associated with selective logging results in spontaneous human colonization, leading to the clearing of mature forest for agricultural purposes. Following 1-3years of cultivation, farmlands are left fallow for periods that may exceed 20years, resulting in extensive secondary forest areas impacted by both selective logging and swidden agriculture. In this study, we assessed forest structure, tree species composition and diversity and the regeneration of timber trees in secondary forest stands (5-10 and ~40years old), selectively logged forest stands, and undisturbed forests at two sites in the Ituri region. Stem density was lower in old secondary forests (~40years old) than in either young secondary or mature forests. Overall tree diversity did not significantly differ between forest types, but the diversity of trees ≥10 cm dbh was substantially lower in young secondary forest stands than in old secondary or mature forests. The species composition of secondary forests differed from that of mature forests, with the dominant Caesalpinoid legume species of mature forests poorly represented in secondary forests. However, in spite of prior logging, the regeneration of high value timber trees such as African mahoganies (Khaya anthotheca and Entandrophragma spp.) was at least 10 times greater in young secondary forests than in mature forests. We argue that, if properly managed and protected, secondary forests, even those impacted by both selective logging and small-scale shifting agriculture, may have high potential conservation and economic value.
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This study examined the impact of disturbance on the pattern of diversity, forest structure and regeneration of tree species in the Vindhyan dry tropical forest of India. A total of 1500quadrats distributed over five, 3-ha permanent plots in five sites, differing in degree of disturbance, were used to enumerate and measure the tree species. A total of 65 species with 136,983 individuals were enumerated in the total 15-ha area for stems 30cm height. The number of species and number of stems ranged from 12 to 50 and 8063–65331per 3-ha area. The number of species and stems for trees 10cmdbh ranged from 3 to 28 species, with a mean value of 16 species ha–1, and from 16 to 477 stems, with a mean value of 256 stems ha–1, respectively. The adult based PCA ordination indicated uniqueness of sites in terms of species composition and habitat characteristics. PCA ordination also showed uniqueness of sites in terms of seedling composition, but the seedling and adult distributions were not spatially associated. The distinct species composition at the different sites and at the two life-cycle stages on the same site is indicative of marked spatio-temporal dynamics of the dry tropical forest. The density–diameter semi-logarithmic curves ranged from a near linear to an overall concave appearance with a limited plateau in the mid-diameter ranges. The -diversity and its components decreased with increasing disturbance intensity, reflecting enhanced utilization pressure with increasing disturbance. The site-wise and species-wise regression analyses of the number of individuals in different stages of the species revealed that both the level of disturbance and the nature of species strongly affect the regeneration. In conclusion, although the forest is relatively species-poor, the differential species composition on different sites and the temporal dynamics lend a unique level of diversity to the tropical dry deciduous forest.
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Forest inventory data were collected in 1998-2000 from fifteen I ha permanent plots along a disturbance gradient in a dry tropical forest region of India. A total of 4033 stems, 49 species, 44 genera and 24 families of adult trees (greater than or equal to30 cm CBH), occurred in the 15 ha of forest area. The study indicated that the dry tropical forest is characterised by a patchy distribution of species and individuals with mixed species composition, and the sites are represented by different combinations of the dominants and co-dominant species. A PCA ordination indicated that the variation in species composition of the sites is explained by the variation in soil nitrogen as well as the degree of disturbance. About half the analysed species showed changing nature in dispersion along the disturbance gradient. The distribution of Boswellia serrata, Holarrhena antidysenterica and Lannea coromandelica changed from clumped to uniform and the distribution of Butea monosperma, Cassia fistula and Elaeodendron glaucum changed from uniform to clumped as the degree of disturbance increased. The mean stem density was highest (419 stems ha(-1)) at the least disturbed site and lowest (35 stems ha(-1)) at the highly disturbed site, and for basal area, the highest value (13.78 m(2) ha(-1)) was for the second least disturbed forest site and the lowest value (1.30 m(2) ha(-1)) was for the most disturbed site. The total number of stems, indices of species richness, evenness and a-diversity decreased with disturbance. A strong influence of number of species per individual on P-diversity suggests that for resisting change in floristics due to disturbance, a site must have low species-individual ratio. (C) 2003 Elsevier B.V. All rights reserved.
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Three different systems of designating protected areas in a Mediterranean region in southeastern Spain were studied, referring to their effectiveness and efficiency for protecting both the breeding territories and the suitable habitat of a set of ten raptor species. Taking into consideration the varying degrees of endangerment of these species, a map of multispecies conservation values was also drawn up and superimposed on the three protected-area systems studied. In order to compare the levels of protection afforded by the three systems, we considered two indices that measured their relative effectiveness and efficiency. The effectiveness estimated the proportion of territories or optimal habitat protected by the networks while efficiency implicitly considered the area of each system (percentage of breeding territories or optimal habitat protected per 1% of land protected). Overall, our results showed that the most efficient system was that formed by the set of regional parks and reserves (17 protected breeding territories per 100 km²), although, given its small total area, it was by far the least effective (only protecting the 21% of the breeding territories of all species and 17% of the area of high conservation value). The systems formed by the Special Protection Areas (designated under the EU "Birds Directive") and by the Special Conservation Areas (designated under the EU "Habitats Directive") notably increased the percentages of protected territories of all species (61%) and area of high conservation value (57%), but their efficiency was not as high as expected in most cases. The overall level of protection was high for all species except for the Lesser Kestrel (Falco naumanni), an endangered falcon that inhabits pseudo-steppe and traditional agricultural habitats, which are clearly underrepresented in the protected-area network of the study region.
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The effects of commercial logging on tree diversity in tropical rainforest are largely unknown. In this study, selectively logged tropical rainforest in Indonesian Borneo is shown to contain high tree species richness, despite severe structural damage. Plots logged 8 years before sampling contained fewer species of trees greater than 20 centimeters in diameter than did similar-sized unlogged plots. However, in samples of the same numbers of trees (requiring a 50 percent larger area), logged forest contained as many tree species as unlogged forest. These findings warrant reassessment of the conservation potential of large tracts of commercially logged tropical rainforest.
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Savannahs are one of the largest biomes of the world, comprising about 20% of the land surface. Stated simply, they are tropical and subtropical grasslands, with scattered bushes and trees. Most savannah occurs in Africa, with a smaller amount in South America, India, and Australia. This book looks at: (1) the climate factors that determine the distribution of savannahs worldwide and briefly looks at savannahs in South America, Australia, India, and Africa; (2) the major plants (grasses, and trees such as Acacia) and large animals (mainly large mammals) that live in African savannahs; and (3) the biological and ecological factors that influence their population size, interactions (such as predation), and community composition. Conservation issues such as tourism, hunting, and the conflict between wildlife and farmers are discussed.
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Recent attempts to streamline the identification of areas requiring immediate conservation attention have resulted in the development of prioritisation procedures that identify areas of biodiversity importance facing large threats in the near future. This study incorporated biodiversity data on bird and vegetation distribution with an assessment of land use suitability for cultivation and afforestation for the Limpopo Province of South Africa. The low altitude savanna regions in the northeast contain high species diversity, but are unsuitable to alternative forms of land use and are well conserved (by e.g., the Kruger National Park). The central and eastern mountain ranges, sites of high biodiversity, are suitable to dryland cultivation and afforestation and are thus potential conservation priorities. Areas with high biodiversity values, e.g., irreplaceable areas that contain biodiversity features essential for meeting conservation targets, were then investigated for their potential land-use threats in order to prioritise those needing immediate conservation actions. We suggest how losses of biodiversity could be minimised by reaching such decisions more quickly.
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1 Species-accumulation curves for woody plants were calculated in three tropical forests, based on fully mapped 50-ha plots in wet, old-growth forest in Peninsular Malaysia, in moist, old-growth forest in central Panama, and in dry, previously logged forest in southern India. A total of 610000 stems were identified to species and mapped to < 1 m accuracy. Mean species number and stem number were calculated in quadrats as small as 5 m × 5 m to as large as 1000 m × 500 m, for a variety of stem sizes above 10 mm in diameter. Species-area curves were generated by plotting species number as a function of quadrat size; species-individual curves were generated from the same data, but using stem number as the independent variable rather than area. 2 Species-area curves had different forms for stems of different diameters, but species-individual curves were nearly independent of diameter class. With < 104 stems, species-individual curves were concave downward on log-log plots, with curves from different forests diverging, but beyond about 104 stems, the log-log curves became nearly linear, with all three sites having a similar slope. This indicates an asymptotic difference in richness between forests: the Malaysian site had 2.7 times as many species as Panama, which in turn was 3.3 times as rich as India. 3 Other details of the species-accumulation relationship were remarkably similar between the three sites. Rectangular quadrats had 5-27% more species than square quadrats of the same area, with longer and narrower quadrats increasingly diverse. Random samples of stems drawn from the entire 50 ha had 10-30% more species than square quadrats with the same number of stems. At both Pasoh and BCI, but not Mudumalai, species richness was slightly higher among intermediate-sized stems (50-100 mm in diameter) than in either smaller or larger sizes. These patterns reflect aggregated distributions of individual species, plus weak density-dependent forces that tend to smooth the species abundance distribution and 'loosen' aggregations as stems grow. 4 The results provide support for the view that within each tree community, many species have their abundance and distribution guided more by random drift than deterministic interactions. The drift model predicts that the species-accumulation curve will have a declining slope on a log-log plot, reaching a slope of 0.1 in about 50 ha. No other model of community structure can make such a precise prediction. 5 The results demonstrate that diversity studies based on different stem diameters can be compared by sampling identical numbers of stems. Moreover, they indicate that stem counts < 1000 in tropical forests will underestimate the percentage difference in species richness between two diverse sites. Fortunately, standard diversity indices (Fisher's α, Shannon-Wiener) captured diversity differences in small stem samples more effectively than raw species richness, but both were sample size dependent. Two nonparametric richness estimators (Chao, jack knife) performed poorly, greatly underestimating true species richness.
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The importance of conservation status of the forest (protected versus unprotected) at two sites with differing human population density (high versus low) on the tree diversity of a Sudanian dry forest in Burkina Faso was studied. All woody species were recorded in 127 circular plots (area = 456.16 m2), and density, dominance, frequency, importance value indices and a variety of diversity measures were calculated to assess the species composition, structure and heterogeneity. A total of 69 species, representing 26 families and 52 genera, were found. Combretaceae, Leguminosae subfamily Caesalpinioideae and Rubiaceae were the dominant families. Neither human pressure nor forest conservation status significantly influenced the tree species richness. Stem density and basal area were significantly higher at the site with high population density than otherwise. Fisher's diversity index revealed the unprotected forest at the site with low population density as the most diverse. We identified species with high conservation importance that should be enriched to maintain a viable population size. In conclusion, the current designation of protected areas seems inefficient at ensuring the conservation of tree diversity in the forest reserve. Thus, participatory conservation programme should be initiated. © 2009 The Authors. Journal compilation
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Mafungabusi State Forest, Zimbabwe, is a protected area of indigenous miombo woodland surrounded almost entirely by communal areas. Tree cutting by residents of the communal areas is legal in the communal areas but illegal in the state forest. The objectives of this study were to determine the spatial pattern of tree cutting in the state forest and the woodlands of the communal area and to compare the wood resources in each. A survey of woody vegetation in plots at increasing distances from the boundary between the state forest and the communal area and a survey of local use of cut wood were conducted. A higher proportion of trees in the communal area showed evidence of past cutting of various types. The incidence of cutting declined steadily with distance from homesteads. The state forest supported a higher basal area, biomass and density of large trees than the woodlands of the communal area. The communal area had a greater variety of vegetation types. These broad differences between the state forest and the communal area were not discernible as sudden changes at the boundary.
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Patterns of higher plant species richness and beta diversity were assessed using standard Modified-Whittaker plots in relation to landuse, slope position and mean annual rainfall across a rainfall gradient in the savanna areas of the Bushbuckridge lowveld, South Africa. In particular, comparison of communal areas with adjacent protected areas was important in showing the impacts of potential changes in landuse within an overarching catchment management plan. Although most of the protected areas considered preservation of biodiversity as their primary goal, they were characterised by significantly fewer plant species than the adjacent, highly utilised, communal lands, at both the plot and point scale. Slope position also had a significant effect on plant species richness, with eutrophic bottomlands having c. 30% more species than the dystrophic toplands. This adds weight to the need for greater public awareness for the judicious use and management of the sensitive bottomlands, which fringe the primary drainage lines that are vital for sustained supplies of good quality surface water in this semi-arid environment. The total number of species increased with increasing mean annual rainfall across the rainfall gradient. This suggests that, if the catchment management plan aims to identify additional areas for conservation, the higher rainfall areas should be the first to be assessed. Species turnover was greater along the rainfall gradient than the catenal gradient between toplands and bottomlands.
Article
Fully protected areas such as National Parks are often assumed to be the best way to conserve plant diversity and maintain intact forest composition and structure. To evaluate this assertion, we sampled trees in areas with four different levels of protection: a National Park, where the protection level is very high, a Game Controlled Area which allows tourist hunting of big game animals, a Forest Reserve which allows selective harvest of trees, and an Open Area where human populations have unrestricted access to forest resources. All four land management areas had healthy size-class distributions with greater numbers of juvenile trees (2–10 cm DBH) than adults. Surprisingly, mean stem density of trees was highest (947 stems ha−1) in the Game Controlled Area but was lowest (635 stems ha−1) in the National Park. The former had the highest basal area value (24 m2 ha−1) while the human-inhabited Open Area had the lowest (11 m2 ha−1). Species richness in the Forest Reserve and Game Controlled Area was significantly higher than in the other areas. The total number of plots with unique species not found anywhere else was lowest in the National. Our measures of forest structure and composition therefore show that fully protected National Parks do not necessarily conserve the greatest diversity of tree species or unique species, indicating that a suite of different types of protection strategies may be the key to conservation of trees in these African dry tropical forests.
Article
We studied the influence of anthropogenic disturbance on forest structure and composition in the highly populated Montane Rain Forests of northern Chiapas, Mexico. We evaluated species richness, basal area and stem density on 81 circular plots (0.1 ha each) along a categorical disturbance gradient due to forest extraction, livestock grazing, and fires. A total of 116 tree species (>5 cm DBH) were recorded in three major forest types recognized by TWINSPAN. The three forest types were: Quercus–Podocarpus Forest (QPF), Pinus–Quercus–Liquidambar Forest (PQLF), and Pinus Forest (PF). The number of canopy and understory trees species, absolute density, and basal area decreased with disturbance intensity. Mean basal area of Pinus spp. was high at intermediate and severe disturbed sites (27 and 19 m2 ha−1, respectively), and low (0.2 m2 ha−1) in well preserved old-growth stands. Distribution of life forms was heterogeneous among forest types, with a high number of understory trees species in QPF, and an impoverished composition in PF. A first axis obtained by factor analysis, represented a combination of anthropogenic disturbance along with environmental and structural variables. Scores of the first factor explained almost 50% of variation, and was positively correlated with livestock grazing, firewood extraction, basal area of Pinus spp. and soil pH, and negatively associated with elevation, plant cover and basal area of Quercus spp. A second factor explained an additional 12% of variation and was associated with forest fires and timber extraction. Distribution of size classes in the QPF was significantly different (p<0.05) than in the other two forest types, including the largest individuals in all inventories. Our results suggest that small scale, but frequent anthropogenic disturbance, increases the dominance of Pinus and drastically decreases floristic richness, mostly understory trees. This points to the need of developing restoration practices aimed to attain highly diverse mixed forests from induced depauperate pinelands. On the other hand, the remnant MRF stands are currently under risk of deforestation in a highly populated Mayan territory, and their conservation under criteria of sustainable use may require finding alternative high value uses not included in conventional commercial forestry.
  • A E Magurran
Magurran A.E. (2004) Measurement Biological Diversity. Blackwell Science Ltd, London.
Tree species diversity in commercially logged Bornean rain forest
  • C H Cannon
  • D R Peart
  • M Leighton
Cannon C.H., Peart D.R. & Leighton M. (1998) Tree species diversity in commercially logged Bornean rain forest. Science 28, 1366-1368.