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Montane Rainforest (montane + rainforest)

Distribution by Scientific Domains
Life Sciences77%

Selected Abstracts

Floristic inventory and diversity assessment of a lowland African Montane Rainforest at Korup, Cameroon and implications for conservation

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2010
Innocent Ndoh Mbue
Abstract Twenty modified-Whittaker plots were stratified at different sampling locations from February to May of 2008 in the central zone of Korup National Park, Cameroon. Our interest was to assess floristic diversity and investigate their relationship with environmental variables. Diversity profiles and rank abundance,curves were used for diversity analysis while canonical correspondence analysis and species,response curves were used to investigate the relationships between the response and explanatory variables. Of the 66 families identified, the Rubiaceae (999 species) were the most abundant. The Sterculiaceae (basal area = 10.482 m2 ha,1) were the dominant family, while the co-dominant families included the Ebenaceae (basal area = 9.092 m2 ha,1) and the Euphorbiaceae (basal area = 8.168 m2 ha,1). Soil variables explained 54.3% of total variation in family distribution. Canonical axes were related to different environmental gradients: axis1 was related to increasing canopy cover (r = 0.6951); axis 2, increasing Magnesium (r = 0.8465) and effective cation exchange capacity (r = 0.5899); axis 3, increasing effective cation exchange capacity (r = 0.5536); while axis 4, increasing Phosphorus concentration (r = 0.5232). Our results demonstrate the advantage which diversity profiles have over single or combination of indices, and the importance of using a combination of methodologies in diversity analysis. Résumé De février à mai 2008, vingt parcelles de Whittaker modifié ont été stratifiées à différents sites d'échantillonnage dans la zone centrale du Parc National de Korup, au Cameroun. Nous voulions évaluer la diversité floristique et étudier son lien avec diverses variables environnementales. Nous avons employé des profils de diversité et des courbes de rangs d'abondance pour l'analyse de la diversité, tandis que nous utilisions une analyse canonique des correspondances et des courbes de réponse des espèces pour étudier les relations entre les réponses et les variables explicatives. Sur les 66 familles identifiées, les Rubiacées (999 espèces) étaient les plus abondantes. Les Sterculiacées (surface basale = 10,482 m2 ha,1) étaient la famille dominante et, parmi les familles co-dominantes, il y avait les Ebénacées (surface basale = 9,092 m2 ha,1) et les Euphorbiacées (surface basale = 8,168 m2 ha,1). Des variables du sol expliquaient 54,3% de la variation totale de la distribution des familles. Les axes canoniques ont été liés aux différents gradients environnementaux; l'axe 1 était liéà une couverture croissante de la canopée (r = 0,6951); l'axe 2 à une augmentation du magnésium (r = 0,8465) et à la capacité réelle d'échange de cations (r = 0,5899); l'axe 3 à une capacité réelle croissante d'échanges de cations (r = 0,5536); et l'axe 4 à une concentration croissante en phosphore (r = 0,5532). Nos résultats montrent l'avantage que les profils de diversité ont sur des indices uniques ou combinés et l'importance d'utiliser une combinaison de méthodologies dans une analyse de diversité. [source]

Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island, South China: (II) Seed Bank

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2008
Run-Guo Zang
Abstract Spatial and temporal patterns of seed bank dynamics in relation to gaps in an old growth tropical montane rainforest of Hainan Island, South China, were studied over two consecutive years. From June 2001 to June 2003, soil seed bank sampling blocks were taken near each of the four sides of each seed trap and immediately put into a nursery for observation of seedling emergence dynamics in four seasons (each experiment in each season). The abundances of seedlings that emerged from seed banks showed the trend of vine functional group (VFG) > shrub functional group (SFG) > tree functional group (TFG) > herb functional group (HFG), but the trend in species richness of seedlings that emerged from the soil seed banks was TFG > VFG > SFG > HFG. The abundances of seedlings that emerged from seed banks in the three gap zones showed no significant differences, but significant differences did exist for the species richness. The time of sampling or seasons of experiments had significant influences on both the species richness and seedling abundances. The seedling emergence processes of each experiment all revealed the unimodal patterns. Few emergences occurred 1 year after each experiment. Compared with those under closed canopies, the recruitment rates from seed to seedlings and from seedlings to saplings in gaps were higher, but the mortality rates from saplings to big trees were also higher in the gaps. [source]

Beta diversity of geometrid moths (Lepidoptera: Geometridae) in an Andean montane rainforest

DIVERSITY AND DISTRIBUTIONS, Issue 5 2003
Gunnar Brehm
Abstract. Turnover in species composition of the extremely species-rich family Geometridae (Lepidoptera) was investigated along an elevational gradient ranging from 1040 m to 2677 m above sea level. Moths were sampled using weak light traps (30 W) in three field periods in 1999 and 2000 in an Andean montane rainforest in the province of Zamora-Chinchipe in southern Ecuador. A total of 13 938 specimens representing 1010 species were analysed. Similarities of ensembles of all geometrid moths and of the subfamilies Ennominae and Larentiinae were calculated using the NESS index (with mmax). Ordinations performed using nonmetric multidimensional scaling (NMDS) and correspondence analysis depicted a gradual change of the ensembles along the altitudinal gradient. Extracted ordination scores significantly correlate with altitude (,0.97 , r , ,0.95, P < 0.001) and with ambient air temperature (0.93 , r , 0.97, P < 0.001). Temperature is therefore assumed to be the most important abiotic determinant responsible for the species turnover among the moths. Matrix correlation tests were performed in order to compare faunal matrices with matrices derived from available environmental factors. Both tree diversity and vegetation structure significantly correlate with faunal data, but tree diversity explains considerably more of the data variability (range: Mantel r = 0.81,0.83, P < 0.001) than vegetation structure (range: Mantel r = 0.35, P < 0.005 to r = 0.43, P < 0.001). Tree diversity also changes gradually and scores of the first NMDS dimension are highly significantly correlated with altitude (r = 0.98, P < 0.001). A common underlying factor such as ambient temperature might also be responsible for such vegetation changes. Additionally, simulated model data was developed that assumed a constant turnover of moth species and equal elevational ranges of all species involved. Despite the simplicity of the models, they fit empirical data very well (Mantel r > 0.80 and P < 0.001 in all models). [source]

Measurements of transpiration in four tropical rainforest types of north Queensland, Australia

HYDROLOGICAL PROCESSES, Issue 26 2007
David McJannet
Abstract Transpiration of four different rainforest types in north Queensland, Australia, was determined using the heat pulse technique for periods ranging between 391 and 657 days. Despite the complexity of the natural rainforest systems being studied, the relationship between sample tree size and daily water use was found to be strong, thus providing a robust means by which to scale transpiration from individual trees to the entire forest stand. Transpiration was shown to be dependent on solar radiation and atmospheric demand for moisture with little evidence of limitation by soil moisture supply. Total stand transpiration was controlled by forest characteristics such as stem density, size distribution and sapwood area. Annual transpiration for each of the four sites ranged between 353 mm for cloud forest and 591 mm for montane rainforest. In comparison with the international literature, transpiration from Australian rainforests is low; the reasons for this could be related to a combination of differences in forest structure, climatic conditions, canopy wetness duration and tree physiology. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Wild coffee management and plant diversity in the montane rainforest of southwestern Ethiopia

AFRICAN JOURNAL OF ECOLOGY, Issue 1 2010
Christine B. Schmitt
Abstract Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land-uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi-forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg ha,1 year,1). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg ha,1 year,1), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers. Résumé Coffea arabica pousse naturellement dans les forêts pluviales de montagne en Ethiopie, mais de grandes superficies de ces forêts uniques ont été transformées pour d'autres usages. Dans la forêt restante, le café sauvage est géré et récolté de façon de plus en plus intense en raison de l'augmentation du prix du café au niveau mondial. Cette étude a évalué l'impact de la gestion des populations sauvages de café, ainsi que la végétation forestière, afin d'établir une base pour la planification de la conservation dans le sud-ouest de l'Ethiopie. Des études de végétation et des évaluations des récoltes ont été réalisées dans une forêt naturelle non gérée et dans des systèmes semi forestiers où les caféiers sont gérés. Les analyses révèlent que la densité des caféiers sauvages et les récoltes de café sont faibles dans la forêt naturelle (max 15 kg ha,1an,1). Dans les systèmes semi forestiers, 30% des arbres de la canopée et la plus grande partie de la végétation en sous-bois ont été enlevés. Cela stimule la croissance des caféiers et augmente fortement les récoltes (max 54 kg ha,1an,1), mais cela perturbe gravement la structure forestière. La richesse en espèces a augmenté de 26%à cause de l'augmentation des espèces dans la végétation rudérale et secondaire; cependant, la richesse et l'abondance des espèces typiquement forestières ont décliné. La conservation de la forêt naturelle exige dès lors le contrôle de la gestion du café sauvage. On discute de la certification du café sauvage comme moyen de réconcilier les mesures de conservation et les intérêts des fermiers locaux. [source]

Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island, South China: (II) Seed Bank

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 5 2008
Run-Guo Zang
Abstract Spatial and temporal patterns of seed bank dynamics in relation to gaps in an old growth tropical montane rainforest of Hainan Island, South China, were studied over two consecutive years. From June 2001 to June 2003, soil seed bank sampling blocks were taken near each of the four sides of each seed trap and immediately put into a nursery for observation of seedling emergence dynamics in four seasons (each experiment in each season). The abundances of seedlings that emerged from seed banks showed the trend of vine functional group (VFG) > shrub functional group (SFG) > tree functional group (TFG) > herb functional group (HFG), but the trend in species richness of seedlings that emerged from the soil seed banks was TFG > VFG > SFG > HFG. The abundances of seedlings that emerged from seed banks in the three gap zones showed no significant differences, but significant differences did exist for the species richness. The time of sampling or seasons of experiments had significant influences on both the species richness and seedling abundances. The seedling emergence processes of each experiment all revealed the unimodal patterns. Few emergences occurred 1 year after each experiment. Compared with those under closed canopies, the recruitment rates from seed to seedlings and from seedlings to saplings in gaps were higher, but the mortality rates from saplings to big trees were also higher in the gaps. [source]

Wild coffee management and plant diversity in the montane rainforest of southwestern Ethiopia

AFRICAN JOURNAL OF ECOLOGY, Issue 1 2010
Christine B. Schmitt
Abstract Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land-uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi-forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg ha,1 year,1). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg ha,1 year,1), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers. Résumé Coffea arabica pousse naturellement dans les forêts pluviales de montagne en Ethiopie, mais de grandes superficies de ces forêts uniques ont été transformées pour d'autres usages. Dans la forêt restante, le café sauvage est géré et récolté de façon de plus en plus intense en raison de l'augmentation du prix du café au niveau mondial. Cette étude a évalué l'impact de la gestion des populations sauvages de café, ainsi que la végétation forestière, afin d'établir une base pour la planification de la conservation dans le sud-ouest de l'Ethiopie. Des études de végétation et des évaluations des récoltes ont été réalisées dans une forêt naturelle non gérée et dans des systèmes semi forestiers où les caféiers sont gérés. Les analyses révèlent que la densité des caféiers sauvages et les récoltes de café sont faibles dans la forêt naturelle (max 15 kg ha,1an,1). Dans les systèmes semi forestiers, 30% des arbres de la canopée et la plus grande partie de la végétation en sous-bois ont été enlevés. Cela stimule la croissance des caféiers et augmente fortement les récoltes (max 54 kg ha,1an,1), mais cela perturbe gravement la structure forestière. La richesse en espèces a augmenté de 26%à cause de l'augmentation des espèces dans la végétation rudérale et secondaire; cependant, la richesse et l'abondance des espèces typiquement forestières ont décliné. La conservation de la forêt naturelle exige dès lors le contrôle de la gestion du café sauvage. On discute de la certification du café sauvage comme moyen de réconcilier les mesures de conservation et les intérêts des fermiers locaux. [source]

Floristic diversity in fragmented Afromontane rainforests: Altitudinal variation and conservation importance

APPLIED VEGETATION SCIENCE, Issue 3 2010
Christine B. Schmitt
Abstract Question: How does the floristic diversity of Afromontane rainforests change along an altitudinal gradient? What are the implications for conservation planning in these strongly fragmented forest areas that form part of the Eastern Afromontane Biodiversity Hotspot? Location: Bonga, southwestern Ethiopia. Methods: Based on evidence from other montane forests, we hypothesized that altitude has an effect on the floristic diversity of Afromontane rainforests in southwestern Ethiopia. To test this hypothesis, detailed vegetation surveys were carried out in 62 study plots located in four relatively undisturbed forest fragments situated at altitudes between 1600 m and 2300 m. Floristic diversity was evaluated using a combination of multivariate statistical analyses and diversity indices. Results: Ordination and indicator species analyses showed gradual variations in floristic diversity along the altitudinal gradient with a pronounced shift in species composition at ca. 1830 m. Upper montane forest (>1830 m) is characterized by high fern diversity and indicator species that are Afromontane endemics. Lower montane forest (<1830 m) exhibits a greater diversity of tree species and a higher abundance of the flagship species Coffea arabica. Conclusions: Our results provide crucial ecological background information concerning the montane rainforests of Ethiopia, which have been poorly studied until now. We conclude that both forest types identified during this study need to be considered for conservation because of their particular species compositions. Owing to the high degree of forest fragmentation, conservation concepts should consider a multi-site approach with at least two protected areas at different altitudinal levels. [source]