RESUMEN
The changes and influencing factors of soil inorganic carbon (SIC) and organic carbon (SOC) on precipitation gradients are crucial for predicting and evaluating carbon storage changes at the regional scale. However, people's understanding of the distribution characteristics of SOC and SIC reserves on regional precipitation gradients is insufficient, and the main environmental variables that affect SOC and SIC changes are also not well understood. Therefore, this study focuses on the Alxa region and selects five regions covered by three typical desert vegetation types, Zygophyllum xanthoxylon (ZX), Nitraria tangutorum (NT), and Reaumuria songarica (RS), along the climate transect where precipitation gradually increases. The study analyzes and discusses the variation characteristics of SOC and SIC under different vegetation and precipitation conditions. The results indicate that both SOC and SIC increase with the increase of precipitation, and the increase in SOC is greater with the increase of precipitation. The average SOC content in the 0-300cm profile is NT (4.13 g kg-1) > RS (3.61 g kg-1) > ZX (3.57 g kg-1); The average value of SIC content is: RS (5.78 g kg-1) > NT (5.11 g kg-1) > ZX (5.02 g kg-1). Overall, the multi-annual average precipitation (MAP) in the Alxa region is the most important environmental factor affecting SIC and SOC.
RESUMEN
We examined the spatial distribution of Tenebrionidae in Alxa Plateau and its environmental response based on the investigation of Tenebrionidae in Alxa Plateau, combined with the temperature, precipitation and solar radiation data, using Grid-Cluster analysis, OriginPro 9.0 and Canoco 5.0 analysis software. The results showed that,with increasing latitude, the number of species rose firstly and declined gradually, with the fitting curve being a parabola. With increasing longitude, the number of species increased gradually, and decreased after the peak, with the fitting curve in approximately unimodal. With increasing altitude, the number of species increased gradually, and decreased after the peak, with the fitting curve showed a single-peak trend. Rainfall, temperature, and solar radiation significantly affected the latitudinal distribution of species richness of Tenebrionidae. Species richness followed a unimodal type with increasing rainfall, peaked in the 38°-39° N. Species richness decreased with increasing temperature and peaked in the 39°-40° N. With the increases of average monthly radiation, Tenebrionidae showed a trend of unimodal type, and peaked at about 16100 kJ·m-2·d-1 (38°-39° N). Solar radiation and rainfall were the main meteorological factors affecting the distribution of Tenebrionidae in the Alxa Plateau.
Asunto(s)
Escarabajos , Conceptos Meteorológicos , Altitud , Animales , China , TemperaturaRESUMEN
In the context of global precipitation anomalies and climate warming, the evolution of fragile desert ecosystems, which account for one-third of the world's land area, will become more complex. Studies of regional climate change and ecosystem response are important components of global climate change research, especially in arid desert regions. Zygophyllum xanthoxylum and Ammopiptanthus mongolicus are two dominant but endangered shrub species in the Alxa Desert in the arid region of central Asia. Using dendrochronological methods, we studied the response of radial growth of those two species to climate factors, and the adaptability of the two shrub populations under a regional warming trend. We found that radial growth of both shrubs was mainly affected by precipitation during the growing season. In additionally, along with the decrease of precipitation and the increase of temperature from east to west of Alxa desert Plateau, the limiting effect of drought during the growing season on radial growth increased. The climate response characteristics and changes between dry and wet periods exhibited spatial and temporal heterogeneity due to micro-level geomorphological factors. Under a regional climate warming trend, individual growth and population development of the two endangered shrubs will be adversely affected. In areas where these species are naturally distributed, populations will gradually become concentrated in micro-geomorphic regions with better soil moisture conditions, such as low-lying areas in the gullies that develop in alluvial fans. This finding has important scientific significance for understanding the development of the region's dominant shrub populations and protection of these and other endangered plants in arid desert areas.