|Other Abstract||Ammopiptanthus (Cheng f.) is a genus of flowing plants in the legume family, a typical is evergreen broadleaf shrub in the deserts of central Asia. It is comprised of two species: A.mongolicus and A.nanus. Both are half endemic and relict species in China. In the past decades, most researches were focus on A.mongolicus, studying about its flora distribution, physiology and ecological characteristics, resistance mechanism, while few studies on large-scale comparative of two kinds of range geographic distribution, habitat characteristics are available. Knowing the Ammopiptanthus’s distribution and habitat characteristics comprehensively and systematically is useful for its biological diversity conservation and sustainable utilization.
In this study, literature data and field survey data were used to complete Ammopiptanthus’s geographical distribution and analysis the Ammopiptanthus’s community characteristics, including species composition and population age structure; First derivative and inverted Gaussian model simulation method were used for comparing the spectral differences between A.nanus and A.mongolicus; Using one-way Analysis of Variance(one-way ANOVA) method to compare the two species of Ammopiptanthus’s habitat differences, including topography, climate and soil characteristics; The Principal Component Analysis(PCA) method was used to analysis the main factors which affecting Ammopiptanthus’s distribution. The main conclusions are as follows:
(1) A.nanus only grew in Kizilsu Kirghiz Autonomous Prefecture of Xingjiang, and the distribution range was 38°55′-40°9′ N, 74°42′-76°43′ E. A.mongolicus mainly distributed in the western of Inner Mongolia , northern of Gansu and Ningxia, and the distribution range was 36°27′- 42°01′ N, 102°36′ - 108°49′ E. Both of them were discontinuous in geographical distribution, showing strip or block mode.
(2) Human activities are the main factors that lead to a reduction of Ammopiptanthus’s distribution area, through comparing the distribution range of Ammopiptanthus from 1958 to 2014. A.mongolicus in Nature Reserve were well protected from damage of human activities, A.nanus’s distribution area is narrow, and its habitat was damaged severely. Therefore, it is urgent to establish Nature Reserve for A.nanus, in order to avoid its extinction.
(3) The community of A.nanus included 17 families, 31 genera and 36 species, while A.mongolicus included 20 families, 46 genera and 58 species. The age structure of the two population Ammopiptanthus was relatively completed. As time goes on, the A.nanus population showed an aging trend, because of the majority middle-age and elderly individuals and fewer young individuals. While, the A.mongolicus population was stable as the large number of young and middle-age individuals. A. nanus and A. mongolicus had similar spectral curve shape, but their red edge position was different due to differences in leaf structure, material composition and environment condition. A.nanus kept spectral characteristics of green vegetation in January, which was significant different from Ephedra przewalskii and Reaumuria soongorica in near infrared band (780-1300 nm). Thus, desert species could be identified by using remote sensing images which taken in winter.
(4) In the growing areas of A.nanus, the altitude range was from 2100 to 2700 m, the slope was from 5 to 45 degree, the average annual temperature was from 3.9 to 6.4℃, the average annual precipitation was from 148 to 168 mm, the Holdridge biological temperature was 7.7℃; The soil was slightly alkaline and the types included rocky soil salinity soil, gypsum brown desert soil, light lime meadow soil and light brown soil. In the growing areas of A.mongolicus, the altitude range was from 990 to 1900 m, the slope was 3 to 40 degree, the average annual temperature was from 5.2 to 8.8℃, the average annual precipitation was from 53 to 252 mm, the Holdridge biological temperature was 9.7℃; The soil was alkaline and the types included calcium earth, wind sand, calcareous gray desert soil, gray-brown desert soil, rocky soil and rocky soil salinity. The analysis of PCA showed that the limiting factors of A.nanus’s distribution were heat indicators, pH, total salt and phosphorus content, while the A.mongolicus’s are water, humidity, organic matter and total nitrogen content.
In this study, using points to represent Ammopiptanthus’s geographical distribution is unable to quantitative analysis temporal variation. In future study, much attention should be paid to the application of remote sensing monitoring species in arid zones. In addition, high resolution data should be used for studying relationship between plants and topography, climate, because microclimate generated topography has great influence on the distribution of plants.|