Habitat richness influences and even determines biological diversity. Plant habitat suitability assessment can provide technical guidance and information support for ecological restoration. Thirteen factors in three categories of terrain, meteorology and soil were chosen to build a habitat suitability assessment index framework in the Upper Reaches of the Min River, based on the local natural environment and the actual influencing factors of vegetative growth. Combined with the Analytic Hierarchy Process (AHP) and entropy method, which were used to calculate weights of indexes, habitat suitability was studied by using a multi-objective linear weighting model and geographic information systems (GIS) spatial analysis techniques. The assessment results are as follows: Altitude, soil stability, aspect and slope have more important effects on plant habitat suitability in the Upper Reaches of the Min River, and their weights are 0.311, 0.260, 0.198 and 0.125, respectively. Suitable and sub-suitable habitats cover 4431.80 km 2 and 6171.12 km 2 , respectively; most of which are distributed along both sides of rivers and have higher suitability. Unsuitable habitats cover the largest area (6679.76 km 2 ), accounting for 29.83% of the whole area; and the worst unsuitable habitats are 5107.23 km 2 (22.81%); they account for more than half of the study area. These results indicate that the plant habitat in the Upper Reaches of the Min River is poor and ecological restoration is both urgent and difficult. Therefore, based on the principle of taking measures suitable to the habitat in ecological restoration projects, ecological and engineering measures should be combined to have better effects, while increasing the strength of ecological protection.

Abstract:The arid valley is a unique type of ecological fragile landscape in the Hengduan Mountain Area, China. The boundary of the arid valley is one of the response indicators to mountainous climate change. Based on the meteorological data from 1999 to 2013 and the SPOT remote sensing images in 1999 and 2013 this study explored the response characteristics of the arid valley boundary to regional climate change in the upper reaches of the Min River in the Hengduan Mountains. The results are as follows: (1) During 1999-2013, the temperature, precipitation, and evaporation increased, and the sunshine duration and relative humidity showed decreasing trends at the rates of 0.008 • C/a, 2.25 mm/a, 5.51 mm/a, −8.72 h/a, and −0.19%/a, respectively. Meanwhile, the climate showed the warm-dry tendency in the southern region and the warm-humid tendency in the central and northern areas. (2) On the whole, the arid valley boundary mainly distributed between 1601-3200 m and moved downward to 2428 m at the speed of −0.76 ± 0.26 m/a along with global warming. The descent speeds in different regions showed the same decreasing order as the regional distributions of precipitation and sunshine duration. (3) The arid valley boundary's displacement in the whole basin had significant negative correlations with current climate change (p < 0.05), as well as with variations of moisture factors. Additionally, with the enhancements of the drought degree and humidity tendency, the variations of temperature, evaporation, and relative humidity, respectively, became the main factors that had significant correlations with the arid valley boundary's displacement. Therefore, climate change during 1999-2013 shows beneficial effects on the improvement of the arid valley habitat in the upper reaches of the Min River. The study provides a new method and gives basic data for research on climate change.

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Few studies have been conducted on the factors and distribution of soil organic carbon (SOC) in plantation forests in arid mountainous regions, especially in orchards. We aimed to unravel the SOC distribution among land‐use types and the effects of altitude gradients and rock fragment content (RFC) on SOC accumulation and sequestration in the Upper Min River Arid Valley, China. The differences in SOC distribution among land‐use types were quantified. The correlation analysis of SOC with various factors, such as altitude and RFC, was conducted. The variation percentage in SOC content and stocks was explained by the factors' contribution using mixed‐effects models. SOC distribution was characterized by high content and low stocks in native forests and shrubs, high content and high stocks in eco‐forest, and low content and high stocks in orchards. At the surface (0–30 cm), SOC content and stocks in orchards (cherry, plum, and apple) were significantly lower than those in eco‐forests. There was a significant positive correlation between altitude and SOC content at the surface but not at the subsoil (30–60 cm). With RFC increased, the surface SOC content decreased in native forests, shrubs, and eco‐forests, while it increased in orchards. Our results suggest that land management is the main factor controlling the variation in SOC distribution. Enhancing the surface SOC stability in orchards by land management is a priority for soil carbon pool management in the Arid Valleys.

Qiang religious culture is the result of its adaptation to the natural environment and socio–economic development. The Upper Reaches of Min River has been the main inhabiting district of the Qiang ethnic group in China. Based on the construction of the resource system for Qiang religious culture, this study quantitatively illustrated the cognitive characteristics of this culture in the basin and the main factors influencing its regional differentiation using statistical methods, Moran’s I method, Getis-Ord Gi* method, and the Geo-detector model. The results suggested that the respondents’ cognitive degree (RCD) in relation to the religious culture in the study area was 0.258 ± 0.031, and the cognitive degrees for religious buildings, supplies, literature, and beliefs were as follows: religious literature (0.332) > religious supplies (0.287 ± 0.076) > religious buildings (0.222 ± 0.037) > religious beliefs (0.193 ± 0.023). This result was mainly related to the dissemination methods of religious cultural elements, the status of their preservation, and changes in the production and lifestyle of the people. Furthermore, the respondents’ cognition presented significant regional differentiation characteristics. Two natural factors, namely, humidity and elevation, were the major ones that influenced cognitive regional differentiation with influences values of 0.293 and 0.280, respectively. Elevation and average night light index exhibited significant correlations with cognition (p < 0.05). Meanwhile, the influence was enhanced when various factors interacted with one another. This study contributes to the quantitative research on the sustainable development of the Qiang religious culture and national culture inheritance.