Monthly Archives: October 2024

Authors: Saneer Lamichhane, Abhinaya Pathak, Aashish Gurung, Ajay Karki, Trishna Rayamajhi, Ambika Prasad Khatiwada, Jeffrey Mintz, Sudip Raj Niroula, Chiranjibi Prasad Pokharel

Abstract: A balanced equilibrium between carnivores and their prey is crucial for maintaining ecosystem sustainability. In this study, we
applied the predator–prey power law equation to assess the balance between the biomass densities of carnivores and their wild
prey within Nepal’s lowland protected areas during 2013, 2018, and 2022. The estimated value of the power law exponent k for
predator–prey biomass was 0.71 (95% CI = 0.39–1.05), indicating an approximate threefold increase in predator biomass density
for every fivefold increase in prey biomass density. Consequently, this creates a systematically bottom-heavy
predator–prey
biomass pyramid. This finding, consistent with the k = 3/4 trophic biomass scaling across ecosystems, suggests that predator
biomass is proportionally sustained by prey biomass, indicating a balance between top predators and their wild prey in Nepal’s
lowland protected areas. We further demonstrated it is possible to retain the overall power law exponent while jointly measuring
intraguild competition between two predators with canonical correlation analysis. This understanding opens avenues for future
research directed toward unraveling the factors that drive these consistent growth patterns in ecological communities.

Journal: Ecology and Evolution

Paper link: https://doi.org/10.1002/ece3.70387

Authors: Khagendra Prasad Joshi, Gunjan Adhikari, Divya Bhattarai, Ayush Adhikari, Saurav Lamichanne

Abstract: The Chure region, among the world’s youngest mountains, stands out as highly susceptible to
natural calamities, particularly forest fires. The region has consistently experienced forest fire
incidents, resulting in the degradation of valuable natural and anthropogenic resources. Despite
its vulnerability, there have been limited studies to understand the relationship of various
causative factors for the recurring fire problem. Hence, to comprehend the influencing factors for
the recurring forest fire problem and its extent, we utilized generalized linear modeling under
binary logistic regression to combine the dependent variable of satellite detected fire points and
various independent variables. We conducted a variance inflation factor (VIF) test and correlation
matrix to identify the 14 suitable variables for the study. The analysis revealed that forest fires
occurred mostly during the three pre-monsoon periods and had a significant positive relation with
the area under forest, rangeland, bare-grounds, and Normalized Difference Vegetation Index
(NDVI) (P < 0.05). Consequently, our model showed that the probability of fire incidents decreases
with elevation, precipitation, and population density (P < 0.05). Among the significant
variables, the forest areas emerges as the most influencing factor, followed by precipitation,
elevation, area of rangeland, population density, NDVI, and the area of bare ground. The validation
of the model was done through the area under the curve (AUC = 0.92) and accuracy (ACC
= 0.89) assessments, which showed the model performed excellently in terms of predictive capabilities.
The modeling result and the forest fire susceptible map provide valuable insights into
the forest fire vulnerability in the region, offering baseline information about forest fires that will
be helpful for line agencies to prepare management strategies to further prevent the deterioration
of the region.

Paper link: https://doi.org/10.1016/j.heliyon.2024.e28525

Authors: Divya Bhattarai, Saurav Lamichhane, Aayoush Raj Regmi, Khagendra Prasad Joshi, Pratik Pandeya, Bijaya Dhami, Ambika Prasad Gautam, Hari Adhikari

Abstract: Invasive alien plant species (IAPS) pose a serious threat to overall plant biodiversity
across the globe. Nepal’s national parks and protected areas are not devoid of the
impact of IAPS. Unfortunately, there is a substantial gap in knowledge regarding the
extent and impact of invasion in protected areas of Nepal. This study assessed the
impact of invasive alien plant species on the resident plant species of the Koshi Tapu
wildlife reserve. After a preliminary field observation, we selected five major IAPS
in the area, Mesosphaerum suaveolens, Chromolaena odorata, Ipomoea carnea, Lantana
camara, and Mikania micrantha for this study. Ten pairs of adjacent plots sized 4 m × 4 m
were surveyed for each invasive species, comprising diverse vegetation types. Each
pair consisted of one “invaded plot” where the invasive species was dominant with
cover greater than 50%, and another “uninvaded plot” laid out in an adjacent area
with similar site conditions but without the invasive species. We calculated the Sørensen Index of Similarity for each paired plot. Wilcoxon rank-sum test was employed to compare ecological parameters between invaded and uninvaded plots for various plant species. Similarly, the difference in impact between each of the five invasive species was assessed using the Kruskal–Wallis test. Species richness varied significantly between invaded and uninvaded plots for C. odorata and I. carnea. The most significant impact on species composition of invaded communities (39.6%) was
observed for C. odorata. The cover of the other dominant species varied significantly
between invaded and uninvaded plots for all five species studied. The Kruskal–Wallis
test showed no significant difference in the impact caused by the five studied invasive
species on Species richness, Shannon–Wiener diversity index, species evenness, and
height of dominant species. However, a significant difference was observed between
the impacts of five studied invasive species and the cover of other dominant species.
The crown cover of dominant species decreased much more in the invaded plots of
L. camara and M. micrantha than in other species. Specialized management efforts are
required to control highly invasive species, such as C. odorata and I. carnea, alongside
proactive measures to prevent further spread in ecologically sensitive areas.

Paper Link: https://onlinelibrary.wiley.com/doi/10.1002/ece3.70316