Nature's patchwork: How water sources and soil salinity determine the distribution and structure of halophytic plant communities in arid environments of the Eastern Pamir

Abstract

The eastern part of the Pamir Mountains, located in Central Asia, is characterized by great climatic continentality and aridity. Wetlands developed in this hostile region are restricted to spring areas, terraces of shallow lakes or floodplains along rivers, and provide diversified ecosystem services e.g. as water reservoirs, refugia for rare species and pastures for domestic cattle. These ecosystems are particularly susceptible to climate changes, that in the Pamir Mountains result in increased temperatures, intense permafrost/glacial melt and alterations of precipitation patterns. Climatic changes affect pasture management in the mountains, causing overutilization of sites located at lower elevations. Thus, both climate and man-induced disturbances may violate the existing ecological equilibrium in high-mountain wetlands of the Eastern Pamir, posing a serious risk to their biodiversity and to food security of the local population. In this context, we sought to assess how environmental drivers (with special focus on soil features and potential water sources) shape the distribution and diversity of halophytic plant communities developed in valleys in the Eastern Pamir. This task was completed by means of a vegetation survey and comprehensive analyses of habitat conditions. The lake terraces and floodplains studied were covered by a repetitive mosaic of plant communities determined by differences in soil moisture and salinity. On lower, wetter sites, this patchwork was formed by Blysmus rufus dominated salt marshes, saline small sedge meadows and saline meadows with Kobresia royleana and Primula pamirica; and on drier, elevated sites, by endemic grasslands with Hordeum brevisubulatum and Puccinellia species and patches of xerohalophytic vegetation. Continuous instability of water sources and summer droughts occurring in the Pamir Mountains may lead to significant structural and functional transformations of described wetland ecosystems. Species more tolerant to decreased soil moisture and/or increased soil salinity will expand, leading to alterations of ecosystem services provided by the Pamirs’ wetlands. The described research will help to assess the current state of the wetlands and to predict directions of their future changes.

Salt stress affects mineral nutrition in shoots and roots and chlorophyll a fluorescence of tomato plants grown in hydroponic culture

“…Salinity constraint is a major abiotic stress to plant health and soil quality as it affects the productivity of most crops. This serious problem has drastically increased in recent years mainly in arid and semi-arid areas (Munns 2002;Mȩtrak et al 2017;Bünemann et al 2018). Salt stress influences a series of some major physiological processes such as photosynthesis, ion partitioning as well as Na + /K + ratio, Reactive Oxygen Species (ROS) and hydraulic conductivity which affects the bioenergetic processes of electron transport chain (Kalaji and Pietkiewicz 1993;Neumann 1995;Steudle 2000;Munns 2002;Allakhverdiev and Murata 2008;Conde et al 2011;Kalaji et al 2011;Fakhrfeshani et al 2015;Oukarroum et al 2015;Almeida et al 2017).…”

Connectivity of Edaphic and Endolithic Microbial Niches in Cold Mountain Desert of Eastern Pamir (Tajikistan)

“…); the subregions are divided by high mountain ranges, which, apart from distance in kilometers, isolate them from each other. The lakes belong to different watersheds, which are not connected to each other; Bulunkul to Yashikul watershed [ 5 , 31 ] while Karakul and Rangkul forming their own small and enclosed catchment areas with no outflows. The straight line distance between Bulunkul and Rangkul is about 135 km, from Rangkul to Karakul is approximately 80 km, and the distance from Bulunkul to Karakul is 160 km, but the distance along the valleys and mountain passes connecting the subregions is much larger.…”

“…The drylands of Central Asia, including the Pamir Mountains, are one of the more poorly studied regions with regards to the diversity and distribution of microbial communities. Eastern Pamir is part of a mountain range, which can be characterized as a cold mountain desert, with sparse vegetation, low nutrient concentration, and low precipitation, and severe climatic conditions [ 4 , 5 ]. Due to its contrasting climatic conditions, complex geology, and varying salinity of the soil, Eastern Pamir is rich in different niches inhabited by microbial communities; studying them provides a good opportunity for studying the microorganisms and the influence of climate change on their development and functioning.…”

“…The previously described differences in climatic conditions prevailing across the high mountains plateau, and divergent hydrology and geomorphology of Eastern Pamir [ 4 , 5 , 29 , 30 ], allowed us to divide the study area into three subregions. They are: Bulunkul in the south, with the wetter and coldest conditions, compared to the Rangkul subregion, which is drier, but a little warmer and is located north-east from Bulunkul, and the third, Karakul located north from Bulunkul and Rangkul and characterized by its dry and cold climatic conditions [ 4 , 5 ]. Endolithic colonization has been previously analyzed only in selected types of rocks (e.g., granites, quartzite, limestones and gneiss) and geographical locations [ 10 , 28 ].…”

Comunidade Halofítica Herbáceo-arbustiva em Perímetro Irrigado do Município de Pentecoste–CE

“…Contudo, o índice de Shannon encontrado em trabalhos realizados por Mętrak et al (2017) e Salvi et al (2017) em áreas sob a influência de elevados níveis de salinidade na Ásia, foi semelhante aos encontrados nas áreas experimentais no perímetro irrigado do município de Pentecoste-CE.…”