Assessing river water quality for ecological risk in the context of a decaying river in India.

The decay of rivers and river water pollution are common problems worldwide. However, many works have been performed on decaying rivers in India, and the status of the water quality is still unknown in Jalangi River. To this end, the present study intends to examine the water quality of the Jalangi River to assess ecological status in both the spatial and seasonal dimensions. To depict the spatiality of ecological risks, 34 water samples were collected from the source to the sink of the Jalangi River with an interval of 10 km while 119 water samples were collected from a secondary source during 2012-2022 to capture the seasonal dynamics. In this work, the seasonality and spatiality of change in the river's water quality have been explored. This study used the eutrophication index (EI), organic pollution index (OPI), and overall index of pollution (OIP) to assess the ecological risk. The results illustrated that the values of OPI range from 7.17 to 588, and the values of EI exceed the standard of 1, indicating the critical situation of the ecological status of Jalangi River. The value of OIP ranges between 2.67 and 3.91 revealing the slightly polluted condition of the river water. The study signified the ecological status of the river is in a critical situation due to elevated concentrations of biological oxygen demand, chemical oxygen demand, and low concentrations of dissolved oxygen. The present study found that stagnation of water flow in the river, primarily driven by the eastward tilting of the Bengal basin, triggered water pollution and ecological risk. Moreover, anthropogenic interventions in the form of riverbed agriculture and the discharge of untreated sewage from urban areas are playing a crucial role in deteriorating the water quality of the river. This decay needs substantial attention from the various stakeholders in a participatory manner.

Global patterns of tree density are contingent upon local determinants in the world's natural forests.

Previous attempts to quantify tree abundance at global scale have largely neglected the role of local competition in modulating the influence of climate and soils on tree density. Here, we evaluated whether mean tree size in the world's natural forests alters the effect of global productivity on tree density. In doing so, we gathered a vast set of forest inventories including >3000 sampling plots from 23 well-conserved areas worldwide to encompass (as much as possible) the main forest biomes on Earth. We evidence that latitudinal productivity patterns of tree density become evident as large trees become dominant. Global estimates of tree abundance should, therefore, consider dependencies of latitudinal sources of variability on local biotic influences to avoid underestimating the number of trees on Earth and to properly evaluate the functional and social consequences.

Worldwide Research Trends in Landslide Science.

Landslides are generated by natural causes and by human action, causing various geomorphological changes as well as physical and socioeconomic loss of the environment and human life. The study, characterization and implementation of techniques are essential to reduce land vulnerability, different socioeconomic sector susceptibility and actions to guarantee better slope stability with a significant positive impact on society. The aim of this work is the bibliometric analysis of the different types of landslides that the United States Geological Survey (USGS) emphasizes, through the SCOPUS database and the VOSviewer software version 1.6.17, for the analysis of their structure, scientific production, and the close relationship with several scientific fields and its trends. The methodology focuses on: (i) search criteria; (ii) data extraction and cleaning; (iii) generation of graphs and bibliometric mapping; and (iv) analysis of results and possible trends. The study and analysis of landslides are in a period of exponential growth, focusing mainly on techniques and solutions for the stabilization, prevention, and categorization of the most susceptible hillslope sectors. Therefore, this research field has the full collaboration of various authors and places a significant focus on the conceptual evolution of the landslide science.

Climate reverses directionality in the richness-abundance relationship across the World's main forest biomes.

More tree species can increase the carbon storage capacity of forests (here referred to as the more species hypothesis) through increased tree productivity and tree abundance resulting from complementarity, but they can also be the consequence of increased tree abundance through increased available energy (more individuals hypothesis). To test these two contrasting hypotheses, we analyse the most plausible pathways in the richness-abundance relationship and its stability along global climatic gradients. We show that positive effect of species richness on tree abundance only prevails in eight of the twenty-three forest regions considered in this study. In the other forest regions, any benefit from having more species is just as likely (9 regions) or even less likely (6 regions) than the effects of having more individuals. We demonstrate that diversity effects prevail in the most productive environments, and abundance effects become dominant towards the most limiting conditions. These findings can contribute to refining cost-effective mitigation strategies based on fostering carbon storage through increased tree diversity. Specifically, in less productive environments, mitigation measures should promote abundance of locally adapted and stress tolerant tree species instead of increasing species richness.

Humedales del Parque Nacional Chirripó, Costa Rica: características, relaciones geomorfológicas y escenarios de cambio climático / Wetlands of the Chirripó National Park, Costa Rica: characteristics, geomorphological relationships and climate change scenarios

Resumen Los humedales, también llamados altoandinos, han sido poco estudiados y caracterizados en Costa Rica. En este estudio se analizan las características geomorfológicas, climatológicas e hidrológicas de los humedales altoandinos del Parque Nacional Chirripó (PNCh), ubicado al centro-sur de Costa Rica, América Central. Para ello se parte de un levantamiento geomorfológico a escala 1:25 000 de formas de relieve particularmente de origen glaciar, el Inventario Nacional de Humedales llevado a cabo por el Proyecto Humedales (PNUD-SINAC-GEF), y la determinación de distintos escenarios de cambio climático para los periodos 2039-2059 y 2079-2099. El objetivo de este trabajo es caracterizar el estado actual de estos ecosistemas, explicar cómo y porqué se forman, así como valorar las posibles implicaciones en el ciclo hidrológico y la provisión de agua de estos reservorios debido a las variaciones del clima a futuro. Los resultados denotan la gran importancia de estos humedales para mantener la dinámica ecológica en el PNCh, así como los servicios de provisión de agua y regulación del ciclo hidrológico en las cuencas que derivan de esta área protegida.(AU)

Abstract The geomorphological, climatological and hydrological characteristics of the high Andean wetlands of the Chirripó National Park (PNCh) are analyzed. The PNCh is located in south-central Costa Rica, Central America. This analysis includes a geomorphological survey on a 1: 25 000 scale of the relief forms and processes, particularly those of glacial origin. The National Wetland Inventory carried out by the Wetlands Project (UNDP-SINAC-GEF) was also used, along with different climate change projections corresponding to the scenarios for the 2039-2059 and 2079-2099 horizons. The main objective is to characterize the current state of these ecosystems, to explain how and why they are formed, as well as to assess the possible implications in the hydrological cycle and the water supply of these wetlands due to future climate variations. The results showed the relevance of these natural reservoirs in maintaining the ecological dynamics of the PNCh. We also studied the services of water provision and regulation of the hydrological cycle in the basins that compose this protected area.(AU)