scholarly journals Phytodiversity and Phytosociology of Riparian Trees Along the Elevation Gradient In The Pamba River, Southern Western Ghats, India

2021 ◽  
Author(s):  
Joby Paul ◽  
E S Adithya ◽  
Nisha P ◽  
Rogimon P Thomas ◽  
Sankaran K S Unni
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
Western Ghats ◽  
Riparian Forest ◽  
Conservation Strategy ◽  
Tropical Rivers ◽  
Tree Species Diversity ◽  
Riparian Trees ◽  
Southern Western Ghats ◽  
Ficus Hispida

Abstract BackgroundThe riparian vegetation along the tropical rivers become threatened due to anthropogenic interference. The tree species diversity and distribution along longitudinal and transversal dimensions is variable and has a pivotal role in the river ecology. The data on the riparian tree species diversity and distribution is inevitable for the nature-based restoration efforts. To test the variability along with the river profile, we investigated the tree species diversity and phytosociology in the tropical river Pamba, Southern Western Ghats. Variation of elevation (701–1923m asl Highrange; 71–700m asl Highland; 8–70m asl Midland and <7.0m asl Lowland) as an indicator of topographic species diversity, we laid a total of 54 × 3 quadrats and data were analyzed with Excel and PC-Ord. ResultsShannon-Wiener's diversity is uniform (1.43689–1.84841) and showed homogeneity (Multiple site similarity index = 0.825396825). Humboldtia vahliana, Neolamarckia cadamba, Vateria indica and Syzygium hemisphericum were showed the highest Importance Value Index. DBH size class (15–>331cm) demonstrated a reverse ‘J’ shaped curve. The tree density and total basal area demonstrated an increasing trend from Lowland to Highrange. Validation of Quadrat data with TWINSPAN and Braun-Blanquet table analysis indicated Ochreinauclea missionis-Ficus hispida-Neolamarckia cadamba in Lowland, Mallotus philippensis-Macaranga peltata-Ficus hispida in Midland, Madhuca neriifolia-Hydnocarpus alpina-Humboldtia vahliana in Highland and Symplocos cochinchinensis var. laurina-Syzygium hemisphericum-Cullenia exarillata in Highrange as dominant stand types. Reciprocal Averaging and Hierarchical Clustering revealed unequivocal classification of quadrats following species composition and elevation. Clumped dispersion was noticed in the Midland and Highland. High regeneration of Madhuca neriifolia, Hopea ponga and Humboldtia vahliana were observed along the elevation gradient.ConclusionsThe present research illustrated that the species diversity of riparian forest in the Pamba river is high and comparable with similar tropical rivers. The phytodiversity, phytosociology and regeneration data are significant for developing a conservation strategy of the anthropogenically fragmented Pamba river. Based on the stand type and regeneration data, Madhuca neriifolia, Hopea ponga, Humboldtia vahliana and Ochreinauclea missionis were suitable for buffer design and restoration along with the Pamba river profile.

Tree Regeneration Characteristics in Limestone Forests of the Cat Ba National Park, Vietnam

2021 ◽  
Author(s):  
Van Vien Pham ◽  
Christian Ammer ◽  
Peter Annighöfer ◽  
Steffi Heinrichs
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Tree Species ◽  
National Park ◽  
Forest Regeneration ◽  
Tree Regeneration ◽  
Conservation Strategy ◽  
Tree Species Diversity ◽  
Site Factor ◽  
Overstory Tree

Abstract Background: Forest regeneration is decisive for future forest development and therefore of major concern to forest ecologists. The ability of overstory tree species to regenerate successfully is important for the preservation of tree species diversity and its associated flora and fauna. This study investigated forest regeneration dynamics in the Cat Ba National Park, a biodiversity hotpot in Vietnam. Data was collected from 90 sample plots and 450 sub-sample plots in the regional limestone forests. We compared species richness between the regeneration and overstory tree layers and examined the effect of environmental factors on the occurrence of regeneration. We developed five ratios to relate overstory and regeneration richness and diversity. Results: We found 97 tree species in the regeneration layer compared to 136 species in the overstory layer. Average regeneration density was 3,764 ± 1,601 per ha. Around 70% of the overstory tree species generated offspring. Of the tree species threatened according to The International Union for Conservation of Nature’s Red List of Threatened Species, only 36% were found in the regeneration layer. A principal component analysis provided evidence that the regeneration of tree species was linked to terrain factors (percentage of rock surface, slope) and soil properties (Cation exchange capacity, pH, humus content, soil moisture, soil depth). Contrary to our expectations, the prevailing light conditions (total site factor, gap fraction, openness, indirect site factor, direct site factor) had no influence on regeneration density and composition, probably due to the small gradient in light availability. Conclusion: We conclude that tree species richness in Cat Ba National Park appears to be declining at present. We suggest similar investigations in other biodiversity hotspots to learn whether the observed trend is a global phenomenon. In any case, a conservation strategy for the threatened tree species in the Cat Ba National Park needs to be developed if tree species diversity is to be maintained.

scholarly journals Tree regeneration characteristics in limestone forests of the Cat Ba National Park, Vietnam

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Van Vien Pham ◽  
Christian Ammer ◽  
Peter Annighöfer ◽  
Steffi Heinrichs
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
National Park ◽  
Humus Content ◽  
Tree Regeneration ◽  
Conservation Strategy ◽  
Tree Species Diversity ◽  
Site Factor ◽  
Overstory Tree ◽  
Threatened Tree Species

Abstract Background The ability of overstory tree species to regenerate successfully is important for the preservation of tree species diversity and its associated flora and fauna. This study investigated forest regeneration dynamics in the Cat Ba National Park, a biodiversity hotspot in Vietnam. Data was collected from 90 sample plots (500 m2) and 450 sub-sample plots (25 m2) in regional limestone forests. We evaluated the regeneration status of tree species by developing five ratios relating overstory and regeneration richness and diversity. By examining the effect of environmental factors on these ratios, we aimed to identify the main drivers for maintaining tree species diversity or for potential diversity gaps between the regeneration and the overstory layer. Our results can help to increase the understanding of regeneration patterns in tropical forests of Southeast Asia and to develop successful conservation strategies. Results We found 97 tree species in the regeneration layer compared to 136 species in the overstory layer. The average regeneration density was 3764 ± 1601 per ha. Around 70% of the overstory tree species generated offspring. According to the International Union for Conservation of Nature’s Red List, only 36% of threatened tree species were found in the regeneration layer. A principal component analysis provided evidence that the regeneration of tree species was slightly negatively correlated to terrain factors (percentage of rock surface, slope) and soil properties (cation exchange capacity, pH, humus content, soil moisture, soil depth). Contrary to our expectations, traces of human impact and the prevailing light conditions (total site factor, gap fraction, openness, indirect site factor, direct site factor) had no influence on regeneration density and composition, probably due to the small gradient in light availability. Conclusion We conclude that the tree species richness in Cat Ba National Park appears to be declining at present. We suggest similar investigations in other biodiversity hotspots to learn whether the observed trend is a global phenomenon. In any case, a conservation strategy for the threatened tree species in the Cat Ba National Park needs to be developed if tree species diversity is to be maintained.

scholarly journals Tree Species Diversity, Composition and Aboveground Biomass Across Dry Forest Land-Cover Types in Coastal Ecuador

2021 ◽  
Vol 14 ◽  
pp. 194008292199541
Author(s):  
Xavier Haro-Carrión ◽  
Bette Loiselle ◽  
Francis E. Putz
Keyword(s):  
Species Diversity ◽  
Land Cover ◽  
Community Composition ◽  
Aboveground Biomass ◽  
Tree Species ◽  
Dry Forest ◽  
Stem Density ◽  
Tree Species Diversity ◽  
Land Cover Types ◽  
Schizolobium Parahyba

Tropical dry forests (TDF) are highly threatened ecosystems that are often fragmented due to land-cover change. Using plot inventories, we analyzed tree species diversity, community composition and aboveground biomass patterns across mature (MF) and secondary forests of about 25 years since cattle ranching ceased (SF), 10–20-year-old plantations (PL), and pastures in a TDF landscape in Ecuador. Tree diversity was highest in MF followed by SF, pastures and PL, but many endemic and endangered species occurred in both MF and SF, which demonstrates the importance of SF for species conservation. Stem density was higher in PL, followed by SF, MF and pastures. Community composition differed between MF and SF due to the presence of different specialist species. Some SF specialists also occurred in pastures, and all species found in pastures were also recorded in SF indicating a resemblance between these two land-cover types even after 25 years of succession. Aboveground biomass was highest in MF, but SF and Tectona grandis PL exhibited similar numbers followed by Schizolobium parahyba PL, Ochroma pyramidale PL and pastures. These findings indicate that although species-poor, some PL equal or surpass SF in aboveground biomass, which highlights the critical importance of incorporating biodiversity, among other ecosystem services, to carbon sequestration initiatives. This research contributes to understanding biodiversity conservation across a mosaic of land-cover types in a TDF landscape.

Diversification of tree stands as a means to manage pests and diseases in boreal forests: myth or reality?

2006 ◽  
Vol 36 (2) ◽  
pp. 324-336 ◽  
Author(s):  
Julia Koricheva ◽  
Harri Vehviläinen ◽  
Janne Riihimäki ◽  
Kai Ruohomäki ◽  
Pekka Kaitaniemi ◽  
...  
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
Boreal Forests ◽  
Tree Mortality ◽  
Tree Species Diversity ◽  
Mixed Stands ◽  
Tree Species Composition ◽  
Pests And Diseases ◽  
Pest Outbreaks ◽  
Disease Epidemics

Pure forest stands are widely believed to be more prone to pest outbreaks and disease epidemics than mixed stands, leading to recommendations of using stand diversification as a means of controlling forest pests and pathogens. We review the existing evidence concerning the effects of stand tree-species diversity on pests and pathogens in forests of the boreal zone. Experimental data from published studies provide no overall support for the hypothesis that diversification of tree stands can prevent pest outbreaks and disease epidemics. Although beneficial effects of tree-species diversity on stand vulnerability are observed in some cases, in terms of reductions in damage, these effects are not consistent over time and space and seem to depend more on tree-species composition than on tree-species diversity per se. In addition, while mixed stands may reduce the densities of some specialized herbivores, they may be more attractive to generalist herbivores. Given that generalist mammalian herbivores cause considerable tree mortality during the early stages of stand establishment in boreal forests, the net effect of stand diversification on stand damage is unlikely to be positive.

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