Land use dictates diversity, density and regeneration of woody species in southwestern Mali, West AfricaAbstractDespite the progression of land degradation and deforestation leading to vegetation fragmentation, most of the population in Mali are still strongly dependent on trees. The current study aimed at exploring how woody species diversity, density and regeneration varies with land use types (farmland, fallow and forest). The study also puts a particular focus on abundance, regeneration and distribution of Parkia biglobosa, a high value tree crop. Data were gathered through systematic vegetation surveys in 48 quadrat plots of 50 × 50 m distributed in three land use types. Ninety one woody species belonging to 72 genera and 30 families were recorded. Land use affected woody species regeneration, density and diversity and the structure of P. biglobosa. The highest mean number of species per plot was recorded in fallow (11.1 ± 1.5) and forest (10.8 ± 0.7) compared with farmland (6.9 ± 1.0). The most abundant regeneration individuals were recorded in the fallow (1998 ± 333 ha−1), followed by forest (1532 ± 167 ha−1) and farmland (897 ± 264 ha−1). For trees, the mean density of 99 ± 26 ind. ha−1 recorded in farmland is similar to fallow (156 ± 46 ha−1) but lower than forest (559 ± 133 ha−1). The lower Shannon's diversity index H′ was also observed in the farmland (1.3 ± 0.1) compared with fallows (1.7 ± 0.2) and forests (1.9 ± 0.1). Spatial distribution of regeneration individuals for each species obtained from Morisita's index showed aggregated patterns for most of the species while Canonical Correspondance Analysis showed more common species between fallow and forest. P. biglobosa trees growing in farmland had the greatest value (57.6 ± 7.0 cm) for collar diameter compared to that of forest (33.7 ± 4.6 cm) and fallow (31.2 ± 4.7 cm). |
Reproductive period of a sub-montaneous tropical forest: estimation of seed availability for forest restoration in mount Masigit-Kareumbi, IndonesiaAbstractThe ability of local tree species (LTS) to produce seeds is an intrinsic factor that contributes to the success of forest restoration efforts through a natural regeneration process. The aim of this study was to investigate the reproductive period of LTS in order to estimate seed sources availability for the forest restoration process in the sub-montaneous forests. Twenty permanent plots (20 × 20 m) were identified at Mt. Masigit-Kareumbi. Observations regarding flowering and fruiting were conducted on 399 individual LTS (78 species, 29 families) that had a diameter at breast height of more than 10 cm. This activity was done every month: period I was from July 2015 to June 2016, and period II was from July 2016 to June 2017. The results showed that the number of flowering–fruiting trees in period I was higher than it had been in period II. Peak flowering–fruiting occurred in period I (30.1% of the total individuals), and the lowest flowering–fruiting occurred in period II (10.5% of total individuals). 242 individual trees (60.7%) in total, comprising 57 species (73.1%), were flowered–fruited. Most LTS had short durations of reproductive phases. The shortest flowering duration was 0.1–0.8 months (61.7%), the shortest flowering–fruiting duration was 0.1–0.5 months (80.0%), and the shortest fruiting duration was 0.1–1.0 months (59.4%). Flowers and fruits or seeds were always available all year round. To support seed availability for forest restoration, the best time for fruit or seed collection is December to January. |
Butterfly diversity and effect of temperature and humidity gradients on butterfly assemblages in a sub-tropical urban landscapeAbstractThe butterfly assemblages of urban ecosystems of Delhi were studied for a period of one year to investigate their diversity. The objective of the study was to understand the dynamics of the butterfly assemblages with respect to changing temperature and humidity levels. We tested the hypothesis that the diversity of butterflies would differ significantly across sampling period owing to pronounced temperature and relative humidity differences throughout the year. The Pollard walk method was used for butterfly survey. Twelve months of intensive sampling at four study sites with 24 temporal replicates per site yielded 14,913 individuals belonging to 75 species. Butterfly community showed a biannual peak of species richness and abundance. The maximum diversity was recorded in the pre-monsoon period between the months of April and May unlike most other studies from India which have reported April–May as the months of lowest diversity. The lowest diversity was observed during winter. Previous studies have shown that tropical insect communities have higher diversity during high precipitation periods. In this study, we found an additional peak of diversity during the pre-monsoon in addition to the post-monsoon months. The study quantitatively assessed community assemblages between ecosystems across a temperature gradient evaluating potential conservation role of natural areas and parks in urban landscapes. |
Spatial determination of soil variables using GIS method and their influence on microbial communities in the Eastern Ghats regionAbstractThe study deals with the spatial distribution of soil variables and their impact on soil microbial communities of Yercaud hills, Eastern Ghats of Tamil Nadu, India. A total of thirteen soil variables was recorded from the soil samples. The soil bacterial and fungal communities were enumerated and representatives were identified. The soil variables were plotted in spatial map using GIS and analyzed by Pearson correlation. PCA, cluster and MDS analysis were performed to recognize the drifts amongst the high linking soil variables and microbial communities. The pH, temperature, EC, organic matter, nitrogen, phosphorus, potassium, calcium, copper, zinc and magnesium were found to be positively significant with the soil microbial communities. It is suggested that the Yercaud hills possess highly fertile, undisturbed soil environment and microbes of novel biotechnological value. |
Flowering pattern of Schizostachyum dullooa , a thin walled tropical bamboo and impact of flowering on regeneration of canopy trees in evergreen forest in North East IndiaAbstractSchizostachyum dullooa is a semelparous, thin walled bamboo that grows in the moist forests of India, Bangladesh and Myanmar. The species has great potential in upliftment of socioeconomic conditions of the rural areas of North East India. The long flowering interval in S. dullooa has hindered documentation of its demography and its influence on regeneration of canopy trees. We hypothesized that mass flowering and death of S. dullooaopens a window of opportunity creating space for the regeneration of canopy tree seedlings. We studied the flowering pattern and seedling demography of this species between the years 2010 and 2015 in the Barak Valley, and evaluated if seedling abundance of canopy tree species increased after the flowering event. We followed five successive seedling cohorts to determine variation in survival of canopy tree seedlings, seedling attributes [i.e., maximum height (cm), diameter (cm) and density (individuals per 0.01 ha)]. At the local scale, mast flowering extended over 4 years in small patches of about 100 m2 where flowering and non-flowering culms were often mixed. At the landscape scale, sites with mast flowering stands were interspersed with sites that did not have flowering stands indicating spatially discontinuous flowering patterns. Mortality rate of bamboo seedlings was high during the first year. At the end of the study, 15–26% of the initial bamboo seedlings in each cohort survived and S. dullooa was able to re-colonize sites it previously occupied. Mass flowering significantly increased seedling density and growth of canopy trees compared to non-flowering sites. It is concluded that flowering and death of S. dullooa facilitates the regeneration of canopy trees, with implications for the structure and function of the forest ecosystem. |
| Towards the transformations of social-ecological systems for sustainable development |
Community structure of gall-inducing insects associated with a tropical shrub: regional, local and individual patternsAbstractThe organization of gall-inducing insect communities can be affected by environmental factors and host plant traits that may operate at different spatial scales. Using Copaifera oblongifolia (Fabaceae), we evaluated the organization of their associated gall-inducing insect species in different spatial scales considering the following hypotheses: (i) the community of gall-inducing insects will be different between different populations of C. oblongifolia; (ii) plant individuals with a greater number of neighbours (host plant density) will have a greater diversity of gall-inducing insects; (iii) and more structurally complex plants will support a greater diversity of gall-inducing insects. Data were collected from the three different populations of C. oblongifolia located in abandoned pastures of three different municipalities in northern Minas Gerais, Brazil. We recorded a total of 17,843 galls belonging to 15 different gall-inducing insect species associated to 60 C. oblongifolia plants sampled in the three populations (20 individuals per population). Abundance, richness and composition of gall-inducing insect species were different between the populations, suggesting that local environmental conditions influenced the gall-inducing insect community at a regional scale. Host plant density negatively affected the richness and abundance of gall-inducing insects per plant. Our data did not corroborate the hypothesis of resource concentration, perhaps due to the effect of resource dilution. The biomass of the host plant positively influenced the abundance of gall-inducing insects per plant. However, the interaction between plant density and biomass of the plant suggests that plants with greater structural complexity are more attacked by gall-inducing insects in plots with lower number of neighbours. |
Invertebrates associated to Ponerine ants nests in two cocoa farming systems in the southeast of the state of Bahia, BrazilAbstractThe fauna associated to nest belonging to nine species of three genera of Ponerinae ants were studied in two cacao agroforestry systems (Cabrua and Derruba Total) in southeast of the state of Bahia, Brazil. A total of 27 invertebrates orders comprising 87 recognized taxonomic units (RTU), were found associated to these nests. No differences were found in the abundances recorded in both agroforestry systems. The high values of the species richness and diversity of associated invertebrates were recorded to Neoponera verenae in both agroforestry systems, while the lowest value was recorded for the nest of Mayaponera constricta collected only in Cabruca. The most frequent groups were Collembola which was found in 95.8% of the reviewed nest, follow by Acari (94.7%), Hymenoptera (other ants species as well as parasitoids; 86.2%), Coleoptera (69.1%), Araneae (51%) and Symphyla (48.9%). Our study also shows the importance of Ponerinae ants' nests as safe habitats that are attractive to many invertebrate groups, and also the importance of the cacao agroforestry system to conservation of a range of invertebrates associated to the nests of these ants. |
Exotic species as the main prey items of the Neotropical otter in the Atlantic Forest, southeastern BrazilAbstractIn this work, the diet of Neotropical otter was characterized in four different hydrographic regions in the southern portion of the Central Atlantic Forest Ecological Corridor, in southeastern Brazil. This was done using scat analysis to determine whether diet composition and the proportion of food items vary between studied regions, and which factors may influence the eventual observed differences. A total of 581 scat samples was taken in the environment and identified prey based on the analysis of undigested structures (scales, bone fragments, exoskeleton) and comparison to the structures contained in a reference collection. All prey were described by large prey groups (classes), and fish and crustaceans were identified to the genus level. The frequency of occurrence for each prey item and the food niche breadth were calculated for each region and for the entire study area. Diet similarities between the regions were visualized by a cluster analysis followed by a Principal Coordinate Analysis from the normalized frequencies. The differences in the prey composition of otter diets were compared among the regions by PERMANOVA. Otters showed a predominantly piscivorous diet, in which exotic cichlids were the main prey. Crustaceans was the second most consumed group. The variations recorded for the otter diet were independent of the study region, which may be related to the food variability among rivers/sampled segments in each region, which in turn may be influenced by differences in habitat structures, including the composition of aquatic biota. |
Accounting tropical forest carbon stock with synergistic use of space-borne ALOS PALSAR and COSMO-Skymed SAR sensorsAbstractThe objective of this study is to precisely quantify the forest aboveground biomass (AGB) and carbon stock in a tropical deciduous forest with synergistic use of space-borne L-band ALOS PALSAR and X-band COSMO-Skymed SAR data, along with field inventory data. AGB serves as a decisive parameter for preparing global decision making policy targeting the impact of reducing emissions from deforestation and forest degradation and climate change. The study proposed optimal regression models for assessing above-ground bole biomass over tropical deciduous mixed forests of Munger (Bihar, India) with synergistic use of ALOS PALSAR and COSMO-Skymed sigma nought images. Coefficient of determination (r2) of 0.89 and RMSE of 15.12 Mg ha−1 were calculated for the best fit integrated model. On validation, the integrated model produced a model accuracy of 78%, r2 = 0.89, RMSE = 16.64 Mg ha−1 and Willmott's index of agreement of 0.934. Resulting modeled AGB were converted to carbon and carbon dioxide equivalents using conversion factors. L-band showed higher accuracy in the estimation in comparison to X-band; but the estimation accuracy improved with the synergistic use of both X- and L-band SAR data. Hence, the study recommends the combined use of X- and L-band SAR with exceptional capabilities for improved assessment of tropical forest stand AGB and carbon with significant contribution towards operational forestry and policy making. |
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