Fishes of the Lower Lulua River (Kasai Basin, Central Africa): A Continental Hotspot of Ichthyofaunal Diversity under Threat

The ichthyofauna of the Lulua River, a large right bank tributary of the Kasai River in central Africa, is among the most poorly documented in the Kasai ecoregion. To remedy this lack of knowledge, sampling was carried out between 2007 and 2014 along the main channel and in many tributaries. A total of 201 species distributed in 81 genera, 24 families, and 12 orders are reported from the lower reaches of the Lulua. The species richness reported in this study represents a substantially improved documentation of the Lulua ichthyofauna (historically estimated at only 79 species). Here, 129 species are recorded for the first time, bringing the total number of known species to 208. Among these, five have recently been described: Raiamas brachyrhabdotos Katemo Manda, Snoeks, Choca Manda, and Vreven 2018, Distichodus kasaiensis Moelants, Snoeks, and Vreven, 2018, Distichodus polli Abwe, Snoeks, Choca Manda, and Vreven 2019, Epiplatys atractus Van Der Zee, Mbimbi, and Sonnenberg 2013, and Hypsopanchax stiassnyae Van Der Zee, Sonnenberg, and Mbimbi 2015; numerous additional taxa are currently under investigation. Recognized here as a continental hotspot of ichthyofaunal diversity, the Lulua is under extreme threat from exploitation of forest products for building materials, deforestation for shifting agriculture and charcoal exploitation, destructive fishing practices, and mining, all of which are rapidly increasing in the watershed. The present study provides baseline documentation for use in conservation planning and future developmental projects in the Kasai ecoregion in general and Lulua River basin in particular.

Forest loss and fire in the Dominican Republic during the 21st Century

Forest loss is an environmental issue that threatens valuable ecosystems in the Dominican Republic (the DR). Although shifting agriculture by slash-and-burn methods is thought to be the main driver of forest loss in the DR, empirical evidence of this relationship is still lacking. Since remotely sensed data on fire occurrence is a suitable proxy for estimating the spread of shifting agriculture, here I explore the association between forest loss and fire during the first 18 years of the 21st Century using zonal statistics and spatial autoregressive models on different spatio-temporal layouts. First, I found that both forest loss and fire were spatially autocorrelated and statistically associated with each other at a country scale over the study period. The hotspots were concentrated mainly in Cordillera Central, Sierra de Bahoruco, Los Haitises/Samaná Peninsula, and the northwestern and easternmost regions. Second, from regional scale analysis, I found no statistical association between forest loss and fire in the eastern half of the country, a region that hosts a large international tourism hub. Third, deforestation and fire showed a joint cyclical variation pattern of approximately four years up to 2013, and from 2014 onwards deforestation alone followed a worrying upward trend, while at the same time fire activity declined significantly. Fourth, I found no significant differences between the deforested area of small (<1 ha) and large (>1 ha) clearings of forest. I propose these findings hold potential to inform land management policies that help reduce forest loss, particularly in protected areas, mountain areas, and the vicinity of tourism hubs.

Agricultural Practices in Lawngtlai Rural Development Block of Mizoram

Agriculture constitutes one of the major sources of income among the people of Mizoram. The areas used for cultivation in Mizoram are usually slashed and burnt down to ashes and are abandoned for years, the land is used and the same plot is re-use after 3-5 years. More than half of the total population is either directly or indirectly involved in agriculture. However, the income from agriculture is less than 5% of the State Gross Domestic Product (State Economic Report, 2015). In the last few decades Mizoram witnessed several changes in agriculture pattern as many farmers have been shifting from cultivation to small- scale agricultural farming. This paper highlights the transformation of agricultural practices and the major factors affecting agricultural production and attempt is made to examine the prevailing socio- economic aspects associated with farmers with special reference to Lawngtlai Rural Development Block and a questionnaire method was used for collecting relevant information for the purpose. The research found that there exist major transformations of agricultural practices in the last couple of decades. The cycle of shifting agriculture period has been shortened drastically. It is also revealed that farmers are gradually adopting settled farming from shifting agriculture and that government intervention and assistance has been increasing more and more in this field. It is suggested that agricultural practice be transformed from jhuming to settled farming and from cultivating the traditional crops to cash crops with governmental and institutional support for shifting to higher income in agricultural and horticultural crops.

Fine Root and Soil Nitrogen Dynamics during Stand Development Following Shifting Agriculture in Northeast India

Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affect fine root dynamics and nutrient cycling processes. Variations in fine root biomass and soil N dynamics were assessed in developing stands of increasing ages following shifting agriculture in Mizoram, Northeast India, and comparisons were made with a natural forest stand. Concentrations of soil available N (NH4-N and NO3-N) and the proportion of NH4-N in total available N increased with stand age. The N-mineralization rate also increased with stand age whilst the proportion of nitrification relative to ammonification declined during succession. Fine root biomass and N-mineralization increased, and available N decreased during the monsoon season while this pattern was reversed during the winter season. A greater proportion of fine roots were <0.5 mm diameter in the younger sites, and turnover of fine roots was more rapid in the developing stands compared to the natural forest. Fine root biomass was correlated positively with N-mineralization rate and soil water content. Thus, it can be concluded that the fine root growth was aided by rapid N-mineralization, and both fine root growth and N-mineralization increase as stands redevelop following shifting cultivation disturbance.

The contribution of fire to a global increase in forest loss

&lt;p&gt;Fire is one of the main drivers of forest loss worldwide and its role varies depending on natural and anthropogenic drivers, ranging from large boreal wildfires to smallholder shifting agriculture. The emergence of higher resolution satellite data creates new opportunities for studying the spatial and temporal relatedness of fires and forest loss. We have quantified this relatedness by overlapping global forest loss for 2001-2018 with fire detections from burned area and active fire satellite products at 500 m resolution. Previous studies have shown that global burned area is decreasing, mostly caused by increased human influence in savanna ecosystems. However, the opposite is true for forests: our study of trends and variability shows that forest loss has increased substantially over the last two decades in many parts of the world and that its dynamics are strongly linked to fire. Striking increases in forest loss were found for rapidly developing regions such as Africa and Southeast Asia, where commodity-driven deforestation and shifting agriculture have led to increased land clearing, often with the use of fire. Besides, stand-replacing wildfire activity has increased in boreal, temperate and tropical forests. The increase in fire activity in forests and decrease in savannas shows that the global balance is shifting because of both natural and anthropogenic factors, with important consequences for the future carbon cycle.&lt;/p&gt;

Runoff and Solute Outputs under Different Land Uses: Long-Term Results from a Mediterranean Mountain Experimental Station

Water availability and quality in Mediterranean environments are largely related to the spatial organisation of land uses in mountain areas, where most water resources are generated. However, there is scant data available on the potential effects of land use changes on surface water chemistry in the Mediterranean mountain region. In order to address this gap in the research, this study investigates the effects of various mountain Mediterranean land covers/land uses on runoff water yielded and water chemistry (solute concentrations and loads) using data from the Aísa Valley Experimental Station (Central Pyrenees) for a long-term period (1991–2011). Nine land covers have been reproduced in closed plots, including dense shrub cover, grazing meadows, cereal, fallow land, abandoned field, shifting agriculture (active and abandoned) and 2 burned plots (one burned in 1991 and the second one burned twice in 1993 and 2001). Results show that all solute concentrations differed among land uses, with agricultural activity producing significantly higher solute loads and concentrations than the other types. Two groups have been identified: (i) the lowest solute concentrations and the smallest quantities of solute loads are recorded in the dense shrub cover, the plot burned once (at present well colonized with shrubs), meadows and abandoned field plots; (ii) the plot burned twice registered moderate values and the highest solute concentrations and loads are found in cereal, fallow land and shifting agriculture plots. Water chemistry is clearly dominated by Ca2+ and HCO3− concentrations, whereas other solutes are exported in very low quantities due to the poor nutrient content of the soil. These results complete the information published previously on soil erosion under different land uses in this experimental station and help to explain the evolution of land cover as a consequence of shifting agriculture, cereal farming on steep slopes and the use of recurrent fires to favour seasonal grazing. They also suggest that promoting the development of grazing and cutting meadows is a good strategy to reduce not only soil erosion but also the loss of nutrients.