International Journal of Environment

Adult Emergence and Morphometrics of Chinese Citrus Fly, Bactrocera minax (Enderlein) (Diptera: Tephritidae) in Nepal

2023-02-12T11:52:41+00:00

Chinese citrus fly, Bactrocera minax is a destructive and univoltine pest of citrus fruits. Geographical altitudinal gradients as well as prevailing climate affect the biology and ecology of insect. Hence, this study aimed to ascertain the effect of altitude on the adult emergence and morphological variations in various ecological settings of Ramechhap district of Nepal from February to June 2021 in citrus orchard. Six altitude ranges were selected in 50 m distance from 1200 to 1500 m above sea level (masl), ranging from 1201-1250 masl, 1251-1300 masl, 1301-1350 masl, 1351-1400 masl, 1401-1450 masl and 1451-1500 masl. The peak adult emergence periods were the 2^nd, 3^rd, 4^th week of April in 1201-1250 masl, 1251-1300 masl, 1301-1350 masl, respectively, followed by 1^st, 2^nd and 3^rd week of May in 1351-1400 masl, 1401-1450 masl, 1451-1500 masl, respectively. Morphometrics of Chinese citrus fly such as weight, length and width of pupa and adult were almost similar to the species collected in various altitudes. The average body length of male Chinese citrus fly adult was 11.58± 0.112 mm while female was 15.57± 0.076 mm. The average wingspan of male was 20.71± 0.285 mm while that of female was 23.14± 0.156 mm. The longevity of adult Chinese citrus fly species increased with increase in altitude. This information could be useful to design an appropriate management plan of Chinese citrus fly in various altitudinal gradients of Nepal.

Regeneration Status and Population Structure in Terai Community Forest: Evidence from Kalyankot Community Forest, Kapilvastu District, Nepal

2023-02-12T11:55:45+00:00

The regeneration status of a forest is an essential metrics to assess the regeneration potential and population structure of forests. In emerging nations like Nepal, however, human dependency on forests has had a negative influence on forest diversity and sustainability. This paper analyzes the regeneration status and its link with bio-physical aspects and human disturbances. The data were collected using a systematic random sampling method and sample plots were established using the fishnet tool in ArcGIS. An inventory survey of 96 plots was carried out with nested circular sample plots with a main radius of 1261 cm. The overall regeneration condition of the forest was found to be in good condition according to Community Forestry Inventory Guideline, 2004. The majority of the tree species were determined to have a sound quality and medium (II) grades in this study. In terms of the diameter class distribution, lower diameter classes (21-60 cm) comprised more adults than the upper diameter classes (61-120 cm). This study found no significant variations in the effects of biophysical factors, such as slope and aspect, on species regeneration. The study concludes the inadequate silvicultural management interventions in the forest. This information can be useful to devise systematic plans to promote good-quality regeneration and manage the factors that are likely to affect the overall regeneration. Further research focusing on other biophysical factors as well as social factors and their influence on regeneration including its management techniques is recommended.

Heavy Metal Tolerance of Bacterial Isolates from Solid Waste Dumping Sites in Abuja, Nigeria

2023-02-12T11:57:20+00:00

Bacteria have special bio-mechanism to resist toxic heavy metals. This study investigated heavy metal tolerance potentials of bacterial isolates from solid waste dumping sites (Abaji, Bwari, Gosa, Gwagwalada, Kuje, and Kwali) in Abuja, Nigeria. Soil samples were randomly collected from each location using soil augers at depths of 0 – 15, 15 – 35 and 35 – 45 cm. They were analyzed bacteriologically using cultural/biochemical techniques and chemically by exposing the isolates to graded concentrations (50 - 400 μg/mL) of chromium (Cr), nickel (Ni) and lead (Pb) on nutrient agar for heavy metal tolerance test. Statistical analysis revealed a significant decrease (p<0.05) in the heterotrophic bacterial count with soil depth; with the highest counts (6.89 × 10⁹ CFU/g) noted at 0 – 15 cm (Gosa) and lowest (1.32 × 10³ CFU/g) found at 30 – 45 cm (Kuje). The isolated bacteria (n=54) were Proteus (33.3 %), Providencia (29.6 %), Pseudomonas (16.6 %), Bacillus (9.3 %), Micrococcus (5.5 %), Escherichia coli (2.1 %), Enterobacter (2.1 %), and Serratia (2.1 %). All these isolates except Micrococcus spp., Enterobacter spp., Escherichia coli and Serratia spp. displayed 100 % resistance to Cr, Ni and Pb at ≥ 200 μg/mL with MICs (μg/mL) being 850 – 1700 (Pseudomonas – Proteus spp.), 950 – 2250 (Pseudomonas – Bacillus spp.) and 900 – 1750 (Pseudomonas – Bacillus spp.), respectively. Majority of these bacteria (24.1 - 38.9 %) were from Gosa and Gwagwalada dumping sites. Our findings suggested these bacteria could be promising for remediation of the heavy metals in the sites.

Controlled Burning and its Effects on Shorea robusta (Sal) Regeneration in Dhansar Block Forest, Rautahat

2023-02-12T12:00:55+00:00

Fire is used as a management tool to administer a wide range of ecosystems worldwide. Forest fires in Shorea robusta (Sal-dominated) forests take the form of ground fires and mostly affect regeneration. We investigated the effect of forest fire on Sal regeneration in 42 sample plots, of which 21 were subjected to controlled burning. The results showed that species richness decreased from fire-unaffected (19) to fire-affected (10). The total density of Sal seedlings in the fire-affected sites was 3829 seedlings ha^-1, while in the fire-unaffected sites were 1779 seedlings ha^-1 representing an increased species dominance of Sal species in the post-fire condition. The total density of Sal saplings in the fire-affected sites was 343 seedlings ha^-1, while in the fire-unaffected sites was 571 seedlings ha^-1. A significant difference with a large effect size (Cohen’s d=0.97) was observed in the seedling regeneration of Sal, while no significant difference was observed in the sapling regeneration of Sal in the post-fire condition. The increment of Sal seedlings may be due to the fire-hardy silvicultural characteristics of Shorea robusta and the decline of Sal saplings may be due to stem mortality in the small diameter classes. We conclude that fire is a beneficial tool for seedling regeneration but not for plant establishment. Future research studies regarding the impact of fire intensities, soil moisture, biological disturbances, temperature, light intensity, etc. on regeneration are recommended.

Diversity of Aquatic Beetles (Dytiscidae) along the Altitudinal Gradient and its Relationship with Physico-Chemical Parameters of Water at Tashiding, Tsendagang and Gozhi Gewogs, Dagana, Bhutan

2023-02-12T12:02:41+00:00

Dytiscidae plays a vital role in the ecosystem; purifies water and serv es as the prey on many organisms. This family of aquatic beetles as predators feeds on small organisms. They are sensitive to environmental changes, it is used as a biodiversity indicator and also a tool for conservation assessment. This study assessed the diversity of Dytiscidae in relation to physico-chemical parameters of water using stratified random sampling at three Geogs in Dagana. Furthermore, the relationship of Dytiscid diversity and taxon richness with the physico-chemical parameters of the lentic and the lotic water bodies along the altitudinal gradient were determined and collected specimens. The total 664 individuals were collected in which five subfamilies of Dytiscidae, 12 genera and 17 species were identified. Pearson’s correlation showed moderately negative correlation between the species diversity and taxon richness based on altitude and pH (p < 0.05). Temperature had moderate positive correlation with species diversity of Dytiscidae. Canonical correspondence analysis (CCA) showed temperature had an effective determining factor for distribution of Dytiscidae. Kruskal Wallis test among different habitats and altitudinal strata showed significant difference in Dytiscids diversity and taxon richness (p < 0.05). The diversity and richness showed a decreasing trend when the altitude increased. The highest diversity was found in marshy area (H = 2.36) and second altitude stratum (800 – 1200 masl) (H = 2.07) in the current study area. Therefore, the best conservation strategy of Dytiscidae could be to protect these areas before they are degraded.

Understanding the Phyllanthus and Terminalia chebula Species Population Change, Dependency and Sustainability: A Study in Malai Mahadeshwara Hills Wildlife Sanctuary, Southern India

2023-02-12T12:05:14+00:00

Non-Timber Forest Products (NTFPs) are vital sources of livelihood for forest-dependent communities across the globe. This study examined the NTFPs species (Phyllanthus emblica, P. indofischeri, and Terminalia chebula) population change determined by the dependency, disturbances, and accessibility in the dry tropical forest of Malai Mahadeshwara (MM) Hills wildlife sanctuary. The long-term monitoring population data were analyzed across three time periods; 2000-01, 2010-11, and 2020-21. The participatory research methods were used to assess the dependency and accessibility which influence the population structure. The multi-factor linkage approach was used to identify the significant drivers of population decline. The results indicated that grazing, fire, hemi-parasite infection, and Lantana invasion influenced the tree population structure and regeneration of study species. This study has also indicated variations and changes in the interrelationship among factors that have a significant role in shaping NTFPs species population structure. Multiple factor analysis determined that grazing, fire, and lantana have significant impacts on population structures, regeneration, and fruit production of NTFPs species. The study recommended that forest managers should consider a site-specific adaptive approach and multiple factors models and inclusive management tools provisioned in recent policies like the Biological Diversity Act -2002 and Forest Rights Act-2006 would hold great potential for developing sustainable use and co-management practices.

Knowledge of resilience strategies in livestock management during dry periods in southwestern Nigeria

2023-02-20T09:21:43+00:00

Recurring elongated dry seasons in South west Nigeria pose a significant threat to livestock production. Knowledge of adaptation strategies to build resilience and lowers vulnerabilities to climate change among livestock farmers is limited. This study assessed livestock farmers’ knowledge of resilience strategies in farm management during dry seasons in southwest Nigeria. Using a purposive sampling procedure, a total of 118 farmers were interviewed on knowledge of livestock management during dry periods, specific challenges to management, and opinions on efficient livestock management. The result shows that increased feed costs challenged farmers during the dry season while insufficient funds were identified as the most severe constraint. Knowledge of management was high among 42% of farmers and 89.5% of them disagreed on the mechanism for temperature control structure in livestock building. Knowledge of good management practices was influenced by farmers’ ability to read and write in Yoruba language (χ2= 9.179; p < 0.05) and constraints faced (r = 0.21; p < 0.05). Climate change information in local languages will improve livestock farmers’ resilience to challenges induced by unpredictable climate change.