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Comparison of Plant Diversity of Natural Forest and Plantations of Rema-Kalenga Wildlife Sanctuary of Bangladesh
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... This sanctuary's terrain consists of undulating hills of varying heights and tiny, low-lying valleys. The highest hilltop is approximately 67 meters above sea level (Sobuj & Rahman, 2011). Several hill ridges are extending in various directions. ...
Due to global climate change, fire dynamics around the world are changing around the world affecting regions more severely that had negligible exposure to forest fire. In this study, we assessed the effect of anthropogenic forest fire using the Normalized Burn Ratio in Rema-Kalenga Wildlife Sanctuary, Bangladesh while evaluating the relationship of this fire index with different spectral indices, and Soil and Vegetation properties. A Correlation and a regression analysis were used to examine the association of different variables with fire severity and One-way analysis of variances (ANOVA) test was also performed to inspect the damage done by fire and the regrowth potential of the forest ecosystem. According to the result, the total burned area was not alarming. Also, the relationship of fire index with spectral indices, and soil and vegetation properties have been meaningful to understand the impact of the forest fire in Rema-Kalenga. Additionally, significant effects of the fire on the variation of the different properties were also observed. Even though the quantity of burned area in this forest was not significant, fire management in the forest conservation strategies in Bangladesh should be heeded and incorporated to avoid future disasters, keeping in mind the future climate change.
... Lagerstroemia speciosa (L.) Pers. is a flood plain species growing in freshwater swamp forests as well as in flood plain valleys of the hill forests. Because of its flood tolerance, L. speciosa has appeared as one of the abundant species in the flood plain valleys of the hill forests of Bangladesh (Sobuj and Rahman, 2011). Previous studies proved that L. speciosa forms distinct annual growth-ring boundaries and is suitable for dendrochronological studies . ...
Bangladesh consists of 80% of the flood plain of the Ganges-Brahmaputra-Meghna river system (GBM), making the country one of the highest flood prone countries of the world. Due to the high rate of discharge of the GBM caused by the summer monsoon and the snowmelt of the Eastern Himalaya and Southern Tibetan Plateau due to climate change, Bangladesh witnessed 16 flood events over 1954-2017. We performed a multiproxy tree-ring analysis to investigate the impact of extreme flood events on tree growth, xylem anatomical parameters and oxygen isotope composition of tree-ring cellulose (δ 18 O tr) in a Bangladeshi moist tropical forest and to establish relationships between water level of the regional rivers and tree-ring parameters. By using pointer year analysis and comparing the pointer years with historical flood records (a cutoff threshold of the country's flooded land area of 33.3%), we identified the three extreme flood events (hereafter called flood years) 1974, 1988, and 1998 in Bangladesh. Superposed epoch analysis revealed significant changes in Tree-ring width (TRW), total vessel area (TVA), vessel density (VD), and δ 18 O tr during flood years. Flood associated hypoxic soil conditions reduced TRW up to 53% and TVA up to 28%, varying with flood events. In contrast, VD increased by 23% as a safety mechanism against flood induced hydraulic failure. Tree-ring δ 18 O significantly decreased during the flood years due to the amount effect in regional precipitation. Bootstrapped Pearson correlation analysis showed that wood anatomical variables encoded stronger river level signals than TRW and δ 18 O tr. Among the wood anatomical parameters , VD showed a strong relationship (r = −0.58, p < 0.01) with the water level of the Manu River, a regional river of the northeastern part of Bangladesh, indicating that VD can be used as a reliable proxy for river level reconstruction. Our analyses suggest that multiproxy tree-ring analysis is a potential tool to study tropical moist forest responses to extreme flood events and to identify suitable proxies for reconstructing hydrological characteristics of South Asian rivers.
... The dispersal rate of entire study area was found to be the highest in trees, followed by herbs and lowest in shrubs. A similar result was noticed by Sobuj & Rahman (2011b) in the Khadimnagar Nation Park for shrubs and herbs. ...
Teak (Tectona grandis L.f.) is a widely planted hardwood tree in Bangladesh, without considering its effects on native forest plants. To study the plant species composition and diversity in a Teak plantation a quantitative vegetation inventory was performed using transect method in the Karnaphuli range of Kaptai reserve forest, Rangamati district, Bangladesh during 2015-2017. The size of the quadrates was 20×20m, 5×5m and 1×1m for trees, shrubs and herbs respectively, to get density, abundance, relative density, relative frequency, basal area, etc. The species composition is presented by density and frequency; the dominancy of species is presented by Importance Value- Index; the species diversity and concentration of dominance is presented by Shannon’s index of diversity. A total of 78 plant species, including 34 trees, 19 shrubs and 25 herbs belonging to 40
families and 70 genera were noticed during the study. The Tectona grandis among trees, Lantana camera in shrubs and Heliotropium indicum in herbs were found to be the dominant species. The family Euphorbiaceae among trees, Rubiaceae and Verbenaceae among shrubs and Araceae among herbs were observed to be the dominant families. Tree species showed contagious whereas shrubs and herb species showed random to contagious distribution pattern. The Shannon’s diversity index for trees, shrubs and herbs were 1.486, 2.624 and 2.944, respectively. This study provides in-depth information about the plant species phytosociological parameters and diversity indices of Teak plantation, which is essential to make conservation strategies for the protection and development of
plant biodiversity.
... Extensive plantation trials of commercial timber species, the Pinus, Eucalyptus and Acacia tree species, were undertaken in Bangladesh PAs [32]. In RKWS, Acacia and Eucalyptus trees were planted through large scale afforestation/reforestation programs, especially in the barren hills and low lands [58,59]. The forest plantation program could have increased forest plantation areas in the first period but might not have contributed to the increase in natural forests in RKWS. ...
In protected areas (PAs) in Bangladesh, as policies shift from net deforestation, conservation initiatives and various management plans have been implemented to reduce deforestation and include public participation at multiple levels. However, the interactive effect of land-related policies on deforestation in PAs is poorly understood. In this study, land-use change analysis using geographic information system data was performed to investigate how policies affected land use and land cover change in Rema-Kalenga Wildlife Sanctuary (RKWS), particularly the National Forest Policy (1979~), National Land Policy (2001~), and Agricultural Land Policy (1999~), using a series of Landsat images captured at different times. Our analyses showed that the total forest area increased in the 1994–2005 period when a plantation program was implemented, and also that many forest areas were replaced with noncommercial agricultural land areas in the 2005–2013 and 2013–2018 periods, when land zoning and co-management programs were implemented under different land-related policies. Commercial and non-commercial agricultural land expansions were the main drivers of deforestation, suggesting that several programs under the different land-related policies could have had synergetic effects on deforestation even in PAs. Our findings emphasize the importance of considering the undesirable effects of land-related policies in Pas, and the need to support the community for forest conservation.
... Different study revealed that NSF had significant higher tree species diversity index as compared to monoculture plantation in uttar prodesh, India [23]; Zimbabwe [24], Ethiopia and Kotiluoto (n.d) [25]. Natural forest showed higher value of biodiversity index in all vegetation layers as compared to monoculture plantation [26]- [29]. ...
To achieve forest management goal it is important to maintain biodiversity. This paper compares understory plant species diversity between exotic monoculture plantation (Acacia auriculiformis) and adjacent natural sal (Shorea robusta) forest. A total of 35 sample plots were taken by random sampling from six patches of adjacent natural sal forest and exotic monoculture plantation. Shannon-Wiener diversity index, species richness and evenness were calculated and compared. Result revealed that, a total of 2,218 plants of 42 species were recorded in natural sal (Shorea robusta) forest. Dominant families were Apocynaceae and Verbanaceae, having three species in each family. Shannon-Wiener diversity index was 2.1 and mean species richness was 14.4. On the contrary, 2,827 plants were found from 15 species in exotic monoculture (Acacia auriculiformis) plantation study area. Dominant family was Leguminosae family. Three species were found under Leguminosae family. Shannon-Wiener diversity index was 0.86 and mean species richness was 4.47. Therefore, Shannon diversity index and richness were significantly higher in natural sal forest as compared to exotic monoculture plantation. Species evenness of natural sal forest was 0.8 and 0.6 for monoculture plantation which indicates less equitable distribution of understory vegetation in monoculture than adjacent natural sal forest. With regard to herb species, evenness was significantly lower in monoculture plantation (0.03) as compared to natural sal forest (0.52). There was no equitable distribution for the herb species under monoculture plantation. Jaccard's similarity index showed that 36% shrub species and 30% of herb species were same in exotic monoculture plantation area and adjacent natural sal forest.
... The dispersal rate of entire study area was found to be the highest in trees, followed by herbs and lowest in shrubs. A similar result was noticed by Sobuj & Rahman (2011b) in the Khadimnagar Nation Park for shrubs and herbs. ...
Teak (Tectona grandis L.f.) is a widely planted hardwood tree in Bangladesh, without considering its effects on native forest plants. To study the plant species composition and diversity in a Teak plantation a quantitative vegetation inventory was performed using transect method in the Karnaphuli range of Kaptai reserve forest, Rangamati district, Bangladesh during 2015-2017. The size of the quadrates was 20×20m, 5×5m and 1×1m for trees, shrubs and herbs respectively, to get density, abundance, relative density, relative frequency, basal area, etc. The species composition is presented by density and frequency; the dominancy of species is presented by Importance Value Index; the species diversity and concentration of dominance is presented by Shannon's index of diversity. A total of 78 plant species, including 34 trees, 19 shrubs and 25 herbs belonging to 40 families and 70 genera were noticed during the study. The Tectona grandis among trees, Lantana camera in shrubs and Heliotropium indicum in herbs were found to be the dominant species. The family Euphorbiaceae among trees, Rubiaceae and Verbenaceae among shrubs and Araceae among herbs were observed to be the dominant families. Tree species showed contagious whereas shrubs and herb species showed random to contagious distribution pattern. The Shannon's diversity index for trees, shrubs and herbs were 1.486, 2.624 and 2.944, respectively. This study provides in-depth information about the plant species phytosociological parameters and diversity indices of Teak plantation , which is essential to make conservation strategies for the protection and development of plant biodiversity. Апстракт Тиковото дрво (Tectona grandis L.f.) е широко распространето садено дрво во Бангладеш без да се води сметка за неговото влијание врз автохтоните растенија. Квантитативни вегетациски истражувања со помош на метод со трансекти беа спроведени во тикова плантажa во подрачјето Карнафули во Шумскиот резерват Каптаи (регион Рангамати, Бангладеш) во тек на
... Natural and artificial stands differ in many aspects: biomass and production component increase in a chronosequence (Jordan and Farnworth, 1982;Usoltsev, 1985Usoltsev, , 1988Gabeev, 1990;Vanclay, 1993, 1995;Usoltsev et al., 1994), single-tree biomass allometry (Usoltsev, 2016;Durkaya et al., 2016) involving its additive case (Usoltsev et al., 2017), resistance to droughts (Khonin, 1974;Makarenko and Biryukova, 1982;Biryukova and Makarenko, 1983;Usoltsev, 1985;Verzunov, 1987;Vanclay, 1993, 1995;Usoltsev et al., 1994;Bell et al., 2015;Navarro-Cerrillo et al., 2018;Rodriguez-Vallejo and Navarro-Cerrillo, 2019), fine root distribution, seasonal pattern and production (Yang et al., 2004), characteristics of the macrostructure of wood (Melekhov et al., 2003;Antonov, 2007), technological properties of wood, in particular, sliced veneer quality (Tekpetey et al., 2014), tree genetic similarity (Gauli et al., 2009), variability of morphological markers of the reproductive organs (Mazhula, 2018), species diversity (Sobuj, 2011), species composition, individual tree distribution, and competitive relationships (Gao et al., 2014), pollinator abundance in crop fields (Taki et al., 2011), reaction to a mass outbreak of parasites (Grabenweger et al., 2005), biomass structure in air pollution gradients near copper plants (Yusupov et al., 1997;Usoltsev et al., 2012), dynamic structural stand density diagrams (Usoltsev and Vanclay, 1995;Stankova and Diéguez-Aranda, 2020). ...
A comparative discussion on advantages and disadvantages of natural stands and plantations, including their productivity and resistance, began from the moment of first forest plantings and continues to this day. In the context, progressive replacement of natural forests by plantations, the question of how that will change the carbon storage capacity of forest cover when replacing natural forests with planted ones in a changing climate becomes extremely relevant. This article presents the first attempt to answer this question at the transcontinental level on a special case for two-needles pine trees (subgenus Pinus L.). The research was carried out using the database compiled by the authors on the tree biomass allocation structure for major tree species of Eurasia, in particular, the 1880 and 1967 data of naturally regenerated and planted sample pine trees, respectively. Multi-factor regression models were calculated after combining the matrix of initial data on the structure of tree biomass with the mean temperature of January and mean annual precipitation; their adequacy indices allow us to consider them reproducible. It is found that the aboveground biomass of equal-sized and equal-aged natural and planted trees increases with the rise in the temperature in the month of January and annual precipitation. This pattern is only partially valid for the branches' biomass. Iit has a specific character for the foliage one. The biomass of all components of planted trees is higher than that of natural trees, but the percentage excess varies among different components and depends on the level of January's temperature, but does not depend at all on the level of annual precipitation. The uncertainties of estimations, as well as the nature of the obtained regularities, are discussed in the text.
The density and guard-cell length of stomata regulate the physiological processes in plants. Yet, the variation of stomatal characteristics among different functional groups of trees has not been adequately understood. Particularly, a comprehensive understanding of stomatal behaviour in Bangladeshi moist forest trees is apparently absent. The study was conducted to investigate how abaxial stomatal density (SD) and guard-cell length (GCL) vary among tree functional types and leaf phenological groups in a moist tropical forest of Bangladesh. Cluster dendrogram revealed three groups of species based on SD and GCL. The independent sample t-test showed that there was a significant difference in SD between evergreen and deciduous tree species (t = 4.18, P < 0.001) but no significant difference in GCL between the two phenological groups. The analysis of variance (ANOVA) revealed no significant difference in SD among the light demanding, intermediate shade tolerant and shade tolerant species (F = 0.76, p = 0.47). However, GCL significantly differed among the three functional groups (F = 3.3, p < 0.05). Maximum theoretical stomatal conductance (gmax) varied between evergreen and deciduous species but did not vary with species shade tolerance. In general, there was a significant trade-off between SD and GCL. However, the inverse relationship was stronger in deciduous and shade tolerant species than in evergreen and shade intolerant species. Leaf dry matter content (LDMC) was positively related with SD and negatively related with GCL. Specific leaf area (SLA) and leaf thickness (LT) were not related to the stomatal traits. Our analyses suggest that leaf phenology and species shade tolerance need to be considered while estimating gas exchange through the stomata in tropical moist forests.
Increasing atmospheric CO2 and subsequent changes in climate have been recognized as the drivers of changes in forest dynamics across the major forest ecosystems around the world. Tropical forests which play a critical role in the global biogeochemical cycles and livelihood subsistence of millions of people have been affected by global change phenomena. Several large scale studies have already provided evidence that forest structure, composition, above- and below-ground biomass and carbon storage of tropical forests have changed in tropical regions due to global environmental changes. Yet, tree growth and physiological processes and their driving forces and mechanisms in different tropical forest ecosystems are not yet adequately understood. Particularly, tree growth at the individual and at the species level and physiological responses of moist tropical forest species are strongly understudied but an utmost important field of research in a global change context. In this thesis, we studied growth and physiological responses of South Asian tropical forest trees to elevated CO2 and climate change using a combination of approaches, including dendroclimatology, stable isotope analysis and modelling. We focused our research on three species from two nature reserves of Bangladesh. We tested whether ring-width chronologies within a site and between sites contain common environmental signals and if climate sensitivity of tropical moist forest trees has increased over time. Furthermore, we modelled tree radial growth responses until the end of the current century for different representative concentration pathways (RCPs). We also tested if drought resilience differs between ecologically contrasting tree species and explored the long-term trends in tree growth and stable carbon isotope based physiological parameters including intrinsic water-use efficiency (iWUE). Finally, we disentangled the relative contributions of climatic variables and atmospheric CO2 in explaining iWUE variability in three tropical moist forest tree species. Statistical parameters like the expressed population signal (EPS) and other chronology statistics of the individual site chronologies and a regional chronology and a strong synchronization between the site chronologies of the three species provide strong evidence of a strong common climate forcing. Climate-growth analysis revealed that temperatures in the early growing season (March-April) strongly negatively affected radial growth in our studied species. Tree radial growth was also negatively influenced by October precipitation and Niño 3.4 region sea surface temperature (SST) anomalies. The inverse relationship between tree radial growth with temperatures in the early and later growing season is most likely linked to the higher evapotranspiration outside of the main monsoon season. An increase in temperature particularly during the hot and dry pre-monsoon season (early growing season) further increases water stress, resulting in tree growth decline. We found that radial growth sensitivity to climate was higher in the recent decades (1986-2015) than the period 1950-1985, likely because trees actively responded to higher temperatures, increasing frequency of droughts, and a prolonged dry season in the recent decades. During previous droughts, tree growth was reduced by 44-56 % depending on the drought events and species. Based on the climate-growth relationships, tree radial growth was predicted to decline by nearly 20 % under RCP 8.5, irrespective of the tree functional type. Growth resilience to drought also differed between species. Tree hydraulic behavior, shade tolerance and radial growth of two years before and after the drought years were found to be linked with tree drought tolerance. A synthesis of published data on long-term trends in tree growth and carbon isotope based physiological parameters across the tropics revealed a general increasing trend in intercellular CO2 concentration (Ci) and intrinsic water-use efficiency (iWUE), while carbon isotope discrimination (Δ13C) remained nearly constant. However, increasing iWUE did not stimulate tree growth in the tropics, probably because negative impacts of changing climate on tree growth have overridden the small positive impacts of rising atmospheric CO2, which was also reflected in our study species. In our study sites, inter-annual variability in iWUE was triggered mainly by temperature variations, whereas long-term iWUE trends were shaped by the elevated atmospheric CO2 concentration. Our findings provide strong evidence that dendrochronology can be successfully applied in South Asian tropical moist forest trees to answer a variety of ecological and physiological questions in a global change context. Tree growth and the associated ecophysiological processes and mechanisms should be in the focus of future research because the carbon sequestration potential of tropical forests is increasingly at risk due to reduced tree growth across the tropics.
Diversity of plant, livestock and fish species, species richness and preferences of farmers were studied in one of the offshore islands of Bangladesh. Assessment was done by means of multistage random sampling. A total of 142 plant species belonging to 61 families were identified in the island, of which 76 species were recorded as tree species, 25 shrub species and 41 herb species. Again out of the plant species, 34 species were fruit producing species, 24 timber species, 21 fuel wood species, 15 medicinal species, 11 ornamental species, 32 vegetable species and 5 species of spices. Most of the farmer (76%) preferred to plant fruit tree species for future plantation followed by timber species (62%). Diversity and abundance of fruit species was found higher in all homestead. Poultry (64%) was the major livestock component of each household followed by Goat (12%), Cattle (10%), Buffalo (8%), and sheep (6%). A total of 24 species of cultured fishes under 14 families were recorded. Among them 9 species were identified as Large sized fishes (Boromaach) and 15 species as Small sized fishes (chhotomaach). The annual income from the homestead biodiversity varies from Tk. 12500 to Tk. 41000 depending on the hosuehold size.
Foliar phenologies of forest understory plants were categorized, and the distribution pattern of leaf habit was examined among different forest environments. Various patterns of foliar phenology were found, especially in herbaceous plants. In addition to the seasonal light regime controlled by the phenology of canopy trees, differences in the length of period with snow cover led to the divergence. Perennial-leaved plants predominate in intensely shaded habitats while annual-leaved plants are more abundant in less shaded habitats. The shade tolerance of perenniel-leaved plants can be considered a preadaptation to snow tolerance. In contrast with the perennial-leaved plants, biennial-leaved plants with leaves overwintering 1 year appear to be favored in euphotic habitats with high insulation both in spring and in autumn. These species are effective competitors in spring because of rapid emergence of current leaves, probably through retranslocation of resources accumulated in the previous year. Another adapt...
. A wooded meadow at Laelatu in western Estonia was found to be very rich in vascular plants. The maximum number of species found was 25 in a 10 cm x 10 cm plot, 42 in a 20 cm x 20 cm plot and 63 in a 1 m2 plot. Species richness is related to the management history of the site. The highest richness was found in sites with the most regular long-term mowing. Species density was lower in the case of fertilization or temporary cessation of mowing. The richest community had an LAI of 2.8 and an above-ground dry biomass of 175 g/m2. With increasing height of the herb layer the number of species decreases. Small disturbances cause a remarkable decrease in species density.
Abstract This paper demonstrates the changes in structure, floristics and forest floor light regimes across the boundary between open forest and rainforest at Kirrama in northeastern Queensland. Hemispherical photographs of the canopy were used to estimate spatial and temporal variations in potential (clear-sky) direct and diffuse photosynthetic photon flux density (PPFD = 400–700 nm) across the boundary. Five vegetation zones were identified across the boundary: (A) open forest, (B) tall open forest, (C) tall open forest with a rainforest under-storey, (D) young rainforest, and (E) mature rainforest. During the summer (September–March) direct PPFD declined semi-exponentially across the boundary, while in the winter (April–August), the decline was more linear. However, the decline in diffuse PPFD across the boundary was linear throughout the year. Mean per cent grass cover was positively correlated and mean per cent shrub cover negatively correlated with annual average total PPFD across the boundary. Mean percentages of diffuse radiation relative to that above the forest (diffuse site factors) ranged from 9.8% in the mature rainforest to 66.4% in the open forest, while mean percentages of direct radiation relative to that above the forest (direct site factors) ranged from 2.9–38.3% at the same sites, respectively. Daily PPFD in the rainforest understorey is probably insufficient for the shade intolerant (pioneer) species which prefer the more open environments on the rainforest margin where light intensities and soil temperatures are higher. Towards the rainforest end of zone C, light conditions appear to be similar to those experienced within small treefall gaps in rainforests. Typically, such light conditions are preferred by shade tolerant (primary) tree species that are unable to grow and reproduce successfully in the adjacent shaded understorey and to compete with the fast growing pioneer tree species in the more open end of zone C.
