Effect of Urbanization on the Diversity of Beetle Families in and around Aizawl, Mizoram

An increase in urbanization and anthropogenic activities has led to a decrease in the area covered by forests which has an impact on the ecosystem and the diversity of flora and fauna. Coleopterans are a group of insects which are known to play an important role to study the impact of urbanization as they act as bioindicators. A study was conducted from September 2018 to October 2019 to determine the effect of urbanization and forest size on the beetle diversity in selected sites representing urban, semi-urban, and rural areas in and around Aizawl, Mizoram. Collection was done by setting up light traps as well as manual collection and other standard methods on a bi-monthly basis. A total of 445 beetles belonging to 15 families were collected. Identification of beetles was carried out only upto family level. Beetles community showed a significant variation in different degrees of urbanization as abundance and species diversity of beetles declined with increasing urbanization in different sites. In terms of the total number of individuals collected, the family Scarabaeidae was the most dominant (21.35%), followed by Cerambycidae (19.77%) and Lucanidae (11.91%) with the highest numbers collected from rural sites. The soil parameters were analyzed which showed a significant correlation with the forest size and this, in turn, affects the beetle diversity. Overall, the diversity of beetles (diversity index, richness, and abundance) is found to be affected in such a way that it is higher in rural sites as compared to urban sites.

Tree Community Composition and Dispersal Syndrome Vary with Human Disturbance in Sacred Church Forests in Ethiopia

Research Highlights: Variations in species composition across church forests in northern Ethiopia were driven more by variations in human disturbance and community forest management than forest size. The degree of human disturbance acted as an environmental filter that selected for weedy, exotic, and wind-dispersed species regardless of forest size. Background and Objectives: Forest fragmentation can profoundly influence the long-term persistence of forests on the landscape. Habitat fragmentation can increase edge effects and limit dispersal between forest patches. In the South Gondar Administrative Zone in northern Ethiopia, many of the remaining forests are small sacred church forests governed by the Ethiopian Orthodox Tewahido Church. Materials and Methods: We examined the drivers of woody plant species composition across 46 church forests in this region, including the influence of elevation, forest size, distance between forests, human disturbance, the presence of a wall, and the importance of local/individual community forest management at the Woreda level. We also examined how dispersal syndromes are influenced by increasing distance between forests and the extent of human disturbance within forests. Results: We found that elevational zone, distance between forests, the degree of human disturbance and Woreda had the greatest effect on species composition. Forest size and the presence of a wall were not significant drivers of species composition in these forests. Conclusions: We propose connecting forests through corridors or scattered trees to increase dispersal between forests, and greater on-the-ground protection efforts to restrict people and cattle from leaving the main trails within sacred forests

Edge effects and human disturbance influence soil physical and chemical properties in Sacred Church Forests in Ethiopia

Aims Tropical forests are increasingly threatened by edge effects as forest degradation and deforestation continues, compromising soil integrity, seedling regeneration capacity, and ecosystem services. Ninety-three percent of the last remaining forests of northern Ethiopia, which number 1022 in the South Gondar region of our study, are <16 ha and are protected because they have a Tewahido Orthodox Christian church at their center. The aim of this study was to determine the effects of human disturbance, forest size, distance from population center and other factors on the soil properties and nutrient status of sacred church forests. We also compared forest soil physical and chemical properties across land cover types in these forests. Methods We assessed the soil physical (water content and bulk density) and chemical (total carbon and nitrogen, available phosphorus, ammonium) properties of 40 sacred church forests across three spatial scales: within individual forests; among forests; and across land cover type (forest, forest edge-exterior, Eucalyptus plantation). We used distance from the edge within each forest to examine edge effects on soil nutrients. Results We found that nutrients and carbon decreased significantly from the interior to the outer edge of these forests and with forest size. Further, the soil of Eucalyptus plantations and areas outside of the forest were largely indistinguishable; both had significantly lower nutrient concentrations than sacred church forest soil. Conclusion Our research highlights the insidious impacts of edge effects and human disturbance on forest soils and the need for an integrated soil management program in the region that balances local needs with forest conservation. The conservation of these sacred church forests is important for maintaining regional soil nutrient status relative to agricultural lands and Eucalyptus plantations.

Trends in discount rates used for forest valuation in New Zealand

Background: The discount rate is a key input for estimating the market value of a forest. Data collected in surveys of forest valuers from 1997 to 2017 indicate a reduction in implied discount rate (IDR) over time with lower IDRs for larger forests. The purpose of this study was to formally analyse these trends. Methods: There are three steps to the analysis:1. Relationships were developed for the IDR data from 1997 to 2017;2. Further relationships were developed for IDR data from 2009 to 2017 for which forest size (i.e. net stocked area) rather than just size class is available; and3. Detailed forest transaction data from 2011 to 2017 were used to develop a model to estimate average crop value from key variables including discount rate. This process allowed an analysis to confirm whether or not trends in discount rate with time and forest size were significant. Results: Analysis of the implied discount rate (IDR) revealed that the reduction over time is significant and that the discount rate for large forests (>10,000 ha) has declined more than for smaller forests. Analysis of data from 2009, for which forest size rather than size class is available, showed that forest area has a significant effect on IDR. Finally, the discount rate within the crop-value model, developed using transaction data collected since 2011, was found to vary with time and forest size; i.e. discount rate decreased as time or forest size increased. Conclusions: Overall, it can be concluded that the discount rates implicit in New Zealand forest transactions have declined over time, with the scale of the reduction depending on forest size.

Effect of fragmentation of kerangas forest on small mammal community structure in Brunei Darussalam

Widespread and rapid forest loss and disturbance have resulted in increased fragmentation of tropical forests. The impacts of forest disturbance and fragmentation on small mammals have been widely studied across the tropics and these studies have highlighted the detrimental effects. However, there is limited understanding on the impacts on small mammals in Borneo. This study investigated the impacts of fragmentation on small mammal community structure in lowland coastal heath forests known as kerangas forests, in Brunei Darussalam. Twelve study sites were compared in three forest types: fragmented (2.07-17.6 ha), disturbed (443.55-483.79 ha) and undisturbed (>500 ha) forests. In addition, the correlations between species richness, abundance and biomass of small mammals, and forest size were investigated. There was a clear change in species composition in the different forest types. Fragmented forests had the lowest species richness but the highest pooled abundance and biomass compared with disturbed and undisturbed forests. Species richness increased with forest size as predicted by the theory of island biogeography. In contrast, abundance and biomass was negatively correlated to forest size. Factors that contribute to the pronounced decline in species richness in fragmented forests include loss of rare and native forest species, reduced forest size in fragmented forests and distance effect. We suggest that a release from top-down control by predators and favourable conditions as a result from forest fragmentation are responsible for higher abundance and biomass of small mammals in fragmented forests.