Browsing by Author "Devi, Ashalata"
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Item An Assessment of the Current Status and Regeneration Potential of the Traditional Conserved Forests (Ngitili) in Kishapu District, Tanzania(TROPICAL PLANT RESEARCH, 2020) Malunguja, Gisandu K.; Rubanza, Chrispinus K. D.; Devi, AshalataThe current study was carried out in the community forests conserved under the indigenous knowledge known as “Ngitili” in Kishapu district of Tanzania. The aim was to assess the current status and determines its regeneration potential in terms of plant species diversity, herbaceous productivity and tree stocking. A field survey was conducted for recording the current status while the phytosociological was carried to recognize vegetation composition and diversity. Regeneration potential was determined based on the population size of seedlings, saplings and adults. Disturbance index was used to calculate the level of disturbances while herbaceous productivity and tree stocking were estimated based on allometric models. Descriptive statistics for quantitative data was analysed using SPSS version 20. The study recorded a total of 10 Ngitili in Kishapu district, out of which, 9 still existing but highly threatened and disturbed, only 1 Ngitili was recorded to be dead (not existing). A total of 66 plant species were recorded of which 20 were grasses, 18 were forbs, and 28 species (17 genera and 13 families) were trees and shrubs. The dominant grass species were Aristida funiculata (28.9%) and Cynodon dactylon, while Monechma debile (4.6%) was the dominant forb. Similarly, Acacia drepanolobium (45.4) and Balanites aegyptiaca (42.9) trees dominated the area. The majority of tree species exhibited a “not regenerating” condition (51.8%) only a few (2.11%) showed a “good regeneration” condition while “newly regeneration” condition recorded 0.00%, with a diversity ranging from 1.86–2.44. Herbaceous and tree stocking potential was 1.23±0.05 t DM ha-1 and 5.66±0.21 t Cha-1 respectively, with a standing stem density (stems ha-1) of 512.07±193.86. The study observed great degradation of the Ngitili characterized by low diversity and poor regeneration conditions. This signified that these community forests are currently threatened and its sustainability is highly at risk unless strong initiatives take place.Item Climate change mitigation through carbon dioxide (CO2) sequestration in community reserved forests of northwest Tanzania(Agriculture and Environmental Science Academy, 2020) Malunguja, Gisandu K.; Devi, Ashalata; Kilonzo, Mhuji; Rubanza, Chrispinus D.K.Forests play a key role in climate change mitigation through sequestering and storing carbon dioxide from the atmosphere. However, there is inadequate information about carbon accumulation and sequestered by community reserved forests in Tanzania. A study was carried to quantify the amount of carbon sequestered in two forests namely; Nyasamba and Bubinza of Kishapu district, northwestern Tanzania. A ground-based field survey design under a systematic sampling technique was adopted. A total of 45 circular plots (15 m radius) along transects were established. The distances between transect and plots were maintained at 550 and 300 m, respectively. Data on herbaceous C stocking potential was determined using destructive harvest method while tree carbon stocking was estimated by allometric equations. The collected data were organized on excel datasheet followed by descriptive analysis for quantitative information using Computer Microsoft Excel and SPSS software version 20, while soil samples were analyzed based on the standard laboratory procedures. Results revealed higher carbon sequestration of 102.49±39.87 and 117.52±10.27 for soil pools than plants both herbaceous (3.01±1.12 and 6.27±3.79 t CO2e/yr) and trees (5.70±3.15 and 6.60±2.88 t CO2e/yr) for Nyasamba and Bubinza respectively. The study recorded a potential variation of soil carbon sequestration, which varied across depths category (P < 0.05). However, there was no difference across sites (P >0.05) and species (P > 0.05) for herbaceous and trees. The findings of this study portrayed a significantly low value for carbon stocking and sequestration potential for enhanced climate change mitigation. Therefore, proper management of community reserved forest is required to accumulate more C for enhancing stocking potential hence climate change mitigation through CO2 sequestration offsets mechanism.Item Heavy Metal Contamination of Forest Soils by Vehicular Emissions: Ecological Risks and Effects on Tree Productivity(springer, 2022-01-29) Malunguja, Gisandu K.; Thakur, Bijay; Devi, AshalataAn ecological study was conducted to evaluate the levels and effects of heavy metals on forest surface soils along highways. We hypothesized that vehicles in highways emit considerable levels of metals, affecting plant diversity and productivity. Pearson correla- tion, cluster, and regression analysis were used to prove these relationships. Furthermore, ecological risk assessments were quantified using the geo-accumulation index, pollution index, pollution load index, and ecological risk index. Results indicated soil samples from Site II (roadway) had higher levels of metals than Site I (control), suggesting that highway traversing via forests emit considerable amounts of metals into the surface soil. The most intriguing aspect is that species such as Bidens Pilosa and Arundo donax were frequently recorded at Site II. The predominance of such species indicates contaminated sites favour- ing metal tolerance species. Ecological risk indices revealed that Cd, Mn, and Pb contrib- uted to ecological risk; their pollution ranged from unpolluted to heavily polluted ecosys- tem. Correlation analysis found a pronounced negative link between metals and diversity; the correlation matrix was −83%, −94%, −65%, −75%, −47%, −57% and − 38% for grass diversity, and − 59%, −74%, −89%, −66%, −81%, −81% and − 83% for forb diversity with Cd, Cr, Ni, Pb, Zn, Cu and Mn, respectively. Furthermore, negative correlations for tree production of −80%, −79%, −76%, −71%, −67%, −53% and − 41% were recorded with Cd, Cr, Ni, Pb, Zn, Cu and Mn, respectively. Nevertheless, metals accounted for 74% vari- ance in tree productivity. The strong negative link observed in this study demonstrates the effects of metals on diversity and productivity, which requires monitoring for preventing serious environmental consequences. Highlights • Excessive road traffic contributes to the release of heavy metal in forests. • Heavy metals in surface soils threaten plant diversity and productivity. • Cd, Mn and Pb are the most substantial contributors to ecological risks.Item Heavy Metal Contamination of Forest Soils by Vehicular Emissions: Ecological Risks and Effects on Tree Productivity.(Springer, 2022-01-29) Malunguja, Gisandu K.; Thakur, Bijay; Devi, AshalataAn ecological study was conducted to evaluate the levels and effects of heavy metals on forest surface soils along highways. We hypothesized that vehicles in highways emit considerable levels of metals, affecting plant diversity and productivity. Pearson correlation, cluster, and regression analysis were used to prove these relationships. Furthermore, ecological risk assessments were quantified using the geo-accumulation index, pollution index, pollution load index, and ecological risk index. Results indicated soil samples from Site II (roadway) had higher levels of metals than Site I (control), suggesting that highway traversing via forests emit considerable amounts of metals into the surface soil. The most intriguing aspect is that species such as Bidens Pilosa and Arundo donax were frequently recorded at Site II. The predominance of such species indicates contaminated sites favouring metal tolerance species. Ecological risk indices revealed that Cd, Mn, and Pb contributed to ecological risk; their pollution ranged from unpolluted to heavily polluted ecosystem. Correlation analysis found a pronounced negative link between metals and diversity; the correlation matrix was −83%, −94%, −65%, −75%, −47%, −57% and−38% for grass diversity, and−59%, −74%, −89%, −66%, −81%, −81% and−83% for forb diversity with Cd, Cr, Ni, Pb, Zn, Cu and Mn, respectively. Furthermore, negative correlations for tree production of −80%, −79%, −76%, −71%, −67%, −53% and−41% were recorded with Cd, Cr, Ni, Pb, Zn, Cu and Mn, respectively. Nevertheless, metals accounted for 74% variance in tree productivity. The strong negative link observed in this study demonstrates the effects of metals on diversity and productivity, which requires monitoring for preventing serious environmental consequences.Item Quantitative Assessment and Predicting the Effects of Soil Pollutants on Herbaceous Biomass Production in Reserved Forests.(Springer, 2021-05-12) Malunguja, Gisandu K.; Devi, AshalataHeavy metal concentrations in surface soils of Reserved Forests (RFs) have a significant impact on understorey herbaceous layer. However, research on their effects on herbaceous productivity and ecological risk in Assam’s RFs is still scarce. Thus, we undertook an eco logical study to gain a better understanding of this. Levels of ecological risks were assessed using geostatistical indices, and the impacts of metals on productivity were predicted using Pearson’s correlation and regression analysis. Results identified a total of 64 herbaceous plants (13 grasses, 42 forbs, and 09 climbers) from 29 families and 61 genera. According to IVI, the dominating grasses, forbs, and climbers were Cynodon dactylon, Datura stramonium, and Piper betle, respectively. Herbaceous productivity was strongly negatively correlated with heavy metals (i.e. Cr (- 94%), Cd (- 83%), Pb (75%), Ni (- 65%), for grasses; and Ni (- 89%), Cr (- 74%), Pb (- 66%), Cd (- 59%) for forbs). This suggested that metals are strong predictors of herbaceous productivity with a significant impact. Meanwhile, the contamination and pollution levels ranged from slightly to severely contaminated and from moderately to highly polluted. Among the metals, Pb and Cd were highly contaminating with significant implications on productivity. Regression analysis found that metals exerted a considerable impact, accounting for approximately 43.4%, 61.7%, 80.0%, and 49.3% of the variances in Cd, Cr, Ni, and Pb, respectively. The empirical model for predicting metals’ Y effects on productivity is: ˆ = 24.977 ? 288.607Cd ? (- 149.635Cr) ? (- 6.534 Ni) ? (- 6.656Pb). Therefore, policymakers must devise efficient metal discharge mitigation techniques in the RFsItem Relationship between Forest Biodiversity Attributes and Potential Carbon Stocks in Dry Tropical Reserve Forests of Assam, Northeast India(University of Latvia, 2021) Malunguja, Gisandu K; Thakur, Bijay; Devi, AshalataPotential forest carbon stocks are significantly correlated to forest biodiversity attributes such as diversity, density, and richness. However, there is little such information on dry tropical reserve forests of Assam, a state in northeast India. We studied this relationship in two reserve forests. Pearson correlation, cluster analysis, and regression analysis were used to explore these relationships. The estimation of plant carbon stocks was made using both destructive methods for herbaceous and non-destructive allometric methods for trees. The most dominant plant species in the Bhomoraguri reserve forest were Cynodon dactylon, Datura stramonium, Clitoria ternatea, and Tectona grandis for grasses, forbs, climbers, and trees, respectively. Cymbopogon nardus, Colocasia esculenta, Mikania micrantha, and Shorea robusta, were dominant species in the Balipara reserve forest for grasses, forbs, climbers, and trees, respectively. The presence of Lantana camara, Smilax ovalifolia and Piper betle in the studied forests suggests disturbed ecosystems. Other observed species such as Aristida spp., Cenchrus spp., Ipomoea cheirophylla, and Sida spp. are indicators of disturbed ecosystems as well. The biomass stock differed significantly among plant growth forms. Carbon stocks were 302.93 and 283.97 t ha–1 in the Bhomoraguri reserve forest and Balipara reserve forest, which were equivalent with 555.87 and 521.30 t ha–1 of CO2 sequestration, respectively. Tree species contributed the greatest amount (54.80%), followed by forbs (21.36%), climbers (19.35%), and least for grasses (4.49%). Correlation analysis indicated a strong positive relationship between the density of trees and climber species with carbon stock potentials, suggesting that increase of their density favoured carbon sequestration in forest ecosystems. Diversity of grasses was negatively correlated with potential carbon stock in the examined forests. The unique contribution of each group to carbon stock was 91.8, 58.01, 51.3, and 11.11% for climbers, trees, grasses, and forbs, respectively. Thus, it is important to examine biodiversity attributes in estimation of forest carbon stocks.