Estimation of the Ecological Degeneration From Changes in Land Use and Land Covers in The Upper Reaches of the Tarim River

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1 Estimation of the Ecological Degeneration From Changes in Land Use and Land Covers in The Upper Reaches of the Tarim River Aniwaer Amut * a b, Lu Gong b, Zhenyan Yuan b, Theodore Crovello c, Zhiqiang Gao d a Xian Jiaotong University; b Xingjiang University (China) and International Center for Desert Affairs (China) and Xinjiang Key Lab. of Oasis Ecology (China), 14 Shengli Road, Urumchi Xinjiang, , China; c California State Univ./Los Angeles; d Institute of Geographical Sciences and Natural Resources Research. ABSTRACT Based on research on the oasis-desert ecosystem, changes in land use of the Akesu-Awati oasis from 1990 to 2000 are analyzed through using the methods of 3S and statistics. A classification system of land use is created and 3S-integration is realized. Using the table of equivalent weight factors of the economic of China s ecosystem services, the loss of ecological resulting from land use changes are estimated. This research shows that changes of land use are notable. Areas of land use such as cropland, residential site and saline land amount increase rapidly in contrast to various degrees of reduction in grassland, forest land, water and wetland. The ecological has become negative, decreasing by yuan. Given such great losses in the estimated economic of ecosystem services, it is clear that the best development of society and economy in the research will be achieved only through comprehensive, planned sustainable development. Key words: land use, the upper reaches of Tarim River, estimation of ecosystem services 1. INTRODUCTION The Tarim River basin is an ecologically sensitive and a key for biodiversity protection and global-change research. The river basin also is important in the production of natural resources associated with the westward expansion of economic development in China. After 40 years of development, the upper reaches are important s for grain and cotton production. Through continued rapid development of the s economy, much of the natural landscape of grassland and forest is undergoing conversion to cropland. The Akesu Oasis is part of the zigzag-shaped zone between the headstreams and the main stream of the Tarim River basin. It is also an ecologically fragile and environmentally critical zone. Extensive utilization of land and water resources has created much of the present-day variation in landscape pattern. This has resulted in major changes of landscape pattern and function. Studies of landscape change within the research are important to help assure sustainable development and conservation of the entire basin. 2. LOCATION AND ENVIRONMENT The oasis is a small isolated fertile in the midst of a sand desert that is surrounded by widespread aridity. It is typically marked by trees and crops, which have a water supply furnished by water flowing from a distant source. It provides suitable environmental conditions for crop growth and human activities. Akesu Oasis lies in west Xinjiang, which is located between 39 o 30' to 41 o 15' north latitudes and 79 o 40' to 82 o 00' east longitudes. It covers two regions including Akesu and Awati with a total of square kilometers. The includes three main geological and geographical features encompassing desert, oasis, and river landscape patterns along with a mountainous. * First author: aniwar.a@xju.edu.cn; phone Remote Sensing and Modeling of Ecosystems for Sustainability III, edited by Wei Gao, Susan L. Ustin, Proc. of SPIE Vol. 6298, 62982H, (2006) X/06/$15 doi: / Proc. of SPIE Vol H-1

2 Akesu Oasis is located within the arid continental climatic zone. Its mean temperature is 10 and mean annual rainfall is 53 mm. Within the research, the Tarim River is fed by three tributaries: the Yarkant, Hotan, and Aksu Rivers. Akesu Oasis has a human population of more than 7.6 million. Development of this region depends largely on agriculture, being important in grain and cotton production. 3. MATERIALS AND METHODS 3.1 The data of LUCC We selected Landsat ETM data of the research region in September 1999 as the main remote sensing data source and the 1:50000 digital grid map which is produced by National Foundation of Geography Information Centers and State Bureau of Surveying and Mapping. We then used the registration and geometric correction of ENVI4.0 to geometrically correct, which made allowed the TM to match the base picture. We extracted the geographical information of the remote image by visual interpretation and use of maximum likelihood supervised classification on the basis of land using map. The ARC/INFO8.0.1 system was used to complete editing and revision of the resulting data. The data were then used to produce the vector map, to obtain the data of LUCC. Based on the character data for this research, land use is divided into 9 types: Cropland, Forestland, Grassland, Water Areas, Residential Areas, Wetland, Saline Areas, Desert and Wasteland. 3.2 Estimate the of ecosystem service When estimating the ecological benefits, people often integrate research results from different s of the world, then summarize the main ecological services and the of ecosystem benefit through counting. Robert Costanza published an article, The of the world's ecosystem service sand natural capital in Nature in , which caused an enormous response throughout the world. It greatly clarified the scientific meaning of the principle and method of estimating the of ecosystem services. In recent years, many scholars 2 3 have studied the purpose, appraisal method and economic worth of the ecosystem service. They also have applied the appraisal model that Constanza put forward to appraise forests, meadows and the economic worth of ecosystem services. On the basis of the appraisal model that Constanza put forward, Xie Gaodi conducted an investigation using a questionnaire sent to more than 200 Chinese scholars of ecology and derived an Equivalent Weight Factor matrix for ecosystem services in China 4. On the basis of the above-mentioned research, this paper attempts to complete the estimate of the ecological services function by using this matrix (Table3-1) Table of Equivalent weight factor of ecosystem services for different ecosystems in China Tab.3-1 Equivalent weight factor of ecosystem services per hectare of terrestrial ecosystems in China forest meadow farmland marsh water wasteland A B C D E F G H I Proc. of SPIE Vol H-2

3 Row A is gas regulated; B is climate regulated; C is water source control; D is form and protection of soil; E is waste disposal; F is protection of bio-diversity; G is food production; H is raw materials; I is recreation and amusement The approach and characteristics used to determine the equivalent weight factoring of each ecosystem service are: (1) Ecological services are divided into gas regulated, climate regulated, water source control, form and protection of soil, waste disposal, bio-diversity maintenance, food production, raw materials production, and recreation amusement.(2) The Ecosystem ecological service factor for each ecosystem service in Table 3-1 is the relative contribution or potential ability to contribute to the ecological service that the ecosystem produced; this is defined as the economic of the normal grain yield of 1 hm 2 compared to the national average of farmland output per year. So as we can change the table of weighting factors into a unit price table of ecological services Determination of the farmland food production service function per unit in the study On the basis of a cereal crops sown, grain production per unit yield and the national average prices of cereal crops, we can calculate according to the following formula: E a m p q n i i i 1 / 7 (i = 1,,n) i 1 M Where Ea is Economic of the food production service function per unit ; i is kind of crop (wheat, rice and maize) in the study ; p(i) is average price of crop i; q(i) is the production of crop i, m i is of crop i; M is the total of all n kinds of crops; and 1/7: economic worth of natural ecosystem without manpower is the 1/7 of economic worth of existing food production per unit The unit ecological service confirmation of each land-use pattern in study Based on the China ecosystem services equivalent factor table (Table 3-1) and the unit food production economic of the study s farmland, one can compute the ecosystem service function unit price of other landuse patterns in the : Eij eij Ea (i = 1,,9,j = 1,,9) Where Eij is the unit price (yuan hm -2 ) of j type i kind ecological service function; e ij is the equivalent factor of j type i kind ecological service function relative to the farmland supplying the ecological service unit price; i is the kind of ecological service function; j is the land use pattern (all 9 land use patterns are given in Table 4-1). Because the equivalent factor of residential was not available, we used s from previous studies; consequently, the production service function for residential is lower and accounts for less than 1% of the study. Since it is such a negligent, if is treated as 0 in subsequent calculations Confirmation of the landscape ecological service function in the study Based on each land-use pattern s and the unit price of its ecological services function, we can calculate the economic of the ecological service function in the study as follows: V 9 i 1 9 j 1 A j E ij (i = 1,,9,j = 1,,9) Where V is the total of ecological service function, Aj is the of j type, E ij is the i kind ecological service unit price of j type; i is the ecological service function type; j is the land use pattern. 4. RESULTS OF THE ANALYSES 4.1 Changes in the study s land use patterns Between 1990 and 2000, the land use in the study has changed enormously (Table 4-1). The s of artificial oases have sharply increased; the of farmland increased by about hm 2 in 10 years. This is has resulted from the destruction of forests and grassland and the reclamation of wasteland by local farmers. Consequently, as the of forest land and grassland continues to shrink, and the amount of cultivated land increases, the amount of artificial disturbance thus is increasing, as is the region s level of instability. The increasing s of artificial oases and of the human population are directly influencing changing in the residential. Proc. of SPIE Vol H-3

4 Such rapid growth of the human population obviously is affecting change in residential, which has been increased by more than a factor of one. The wetland s drops suddenly, to about half of the. Most wetlands have been transformed into paddy fields or ponds, with wetlands now mostly occurring around the periphery and in the water s of the oasis. By contrast, the of the water s slightly drops. But most important is that the total of the region s natural water s is constantly decreasing. At the same time, regional water consumption increases, which leads to decreased flow along foot-paths. This and the enlargement of artificial reservoirs increase the actual and relative amount of artificial water s. To summarize the water situation, while changes in total water does not seem significant, significant changes have occurred in terms of how such water is distributed within water s subcategories. Soil salinization in the study district has been significantly and continuously aggravated over the 10 years. In the oasis and in the intermediate zone between the oasis and the desert, we see large s of salt and alkaline lands, and such s are rapidly increasing. In addition, the amount found in the sand category has increased by about hm 2, further strongly increasing the threats to the local ecological communities. These changes are seriously threatening the overall security and the stability of the oasis. Tab.4-1 Changes of s of land use in research from 1990 to 2000(hm 2 ) farmland forest grassland water residents wetlalnd salinealkali sand wasteland change of land Changes in ecological s The ecological service s economic of the In this research we chose wheat, rice and maize as the main cereal crops. We determined the study s prices, the per unit yield and the total sown in 1990 and These data were used to obtain study district s main price over the 10 years, the average per unit yield, and the average sown for each cereal crop (Table 4-2 ). Tab.4-2 Price, average production per hectare and planting of main types in research kinds of price of grain crops yield(t hm grain - cropping (yuan t crops -1 ) 2 ) (hm 2 ) wheat 568.9(unchang in 90 years) rice 850.4( unchang in 90 years ) maize 425.4( unchang in 90 years ) According to these data we calculated this district s farmland s food unit price to produce services of yuan hm-2 over the 10 years. This information allowed us to calculate each service function s unit price the study (Table 4-3 ) for the different land use patterns. Proc. of SPIE Vol H-4

5 Tab. 4-3 Economic per hectare of ecosystem services in the research forest grassland farmland wetland water unused land A B C D E F G H I Totals The ecological service function and change of study district view study district in 1990 and 2000 Using all combinations of service function of each land use pattern and the s of each land use type in the study in 1990 and 2000, we then were able to estimate the ecological service function of the study district for 1990 and Table 4-4 indicates that the study district s ecological service function s are and respectively in 1990 and 2000, resulting in a reduction of more than yuan between 1990 and Landscape patches Tab.4-4 Economic of ecosystem services in research in 1990 and Per s (yuan hm -2 ) (hm -2 ) Ecological (yuan) Per s (yuan hm -2 ) (hm -2 ) Ecological (yuan) increase and decrease of Ecological Cropland Forest land Grassland Water Residential site Wetland Saline Desert Waste land Total Proc. of SPIE Vol H-5

6 The ecological increase of farmland is mainly the result of the rapid increase in farmland during this time. The increase in ecological of farmland also must consider the loss of the ecological of the land use type of as a cost. The wetlands economic worth is reduced most of all, by yuan. This is mainly because the that the wetland unit affects the service function more than other uses. From1990 to 2000, the wetland decreased rapidly, in reality, due to increases in such destructive human activities as overgrazing, excess reclamation, etc. Unfortunately, wetlands decrease also means that the important wetland functions are being seriously destroyed. As wetland vegetation is reduced, animal diversity and numbers also constantly decrease. The change in ecological of meadow and forest land is and respectively. Meadow and forest land have been relatively large land use patterns in the study. However, within 10 years, human activity such as forest and grassland destruction and thus increasing wasteland s, the structure and function of the two have been influenced to varying degrees Comparison between ecological service function and gross national product in the study district between 1990 and 2000 According to available statistical yearbook information, the gross national product in the study rose from yuan to yuan between 1990 and 2000, an increase of yuan over the 10 years, with an average annual rate of increase of 7.8%. At the same time, the study district s ecological was reduced by CONCLUSION The loss of ecological in the study district was significant and reflects the environmental price that the region has paid to accomplish the s increased economic growth. With such rapid enlargement of this oasis, population, pressure on the environment has become the three bottlenecks to achieving sustainable development in this. Population growth already has negatively affected the ability and the rate of grain production. Also, the increased of land resource production has deviated from increasing or even just maintaining the ecological, causing the to be seriously out-of-balance. Ignoring the loss in the natural environment and pursuing economic growth blindly, the ultimately will be unable to realize the greatest of both economy and society. The prominent reduction of the ecological in the study over the 10 years underscores the necessity and and critical importance in assessing the of ecosystem services. And further emphasizes that such assessments mut be include in regional planning at all levels. Only in this way can it promote effective protection of the ecosystem and thus maintain the ecological foundation for social and economic development and realize development for a significant length of time. There is a strong need to publicize the fact that this is not an isolated study. Rather, over the past decade and more, we have already carried out many different research studies, all with the goal to estimate the of ecosystem services. Such data will become increasingly important and useful. Additionally, more disputes in allowed land use, etc. will further increase the need for reliable estimates of the of ecosystem services. The of typical oasis ecological service and function in the Tarim River Basin and results of that change, estimated both in 1990 and 2000, is conservative and requires further study to increase accuracy. Nevertheless, results reported here are reliable enough to make people realize the great losses occurring due to blind development and overuse of land resources that are destructive even in the short run. Only through increased awareness and protection of ecology and environmental sustainability, will the goal of the development of the oasis in ways that are both highly efficient and also sustainable and stable be realized. REFERENCES 1 Robert Costanza et al. The Value of the World's Ecosystem Service sand Natural Capital[J].Nature,1997,38(7): Ou yang Zhi yun, Wang Ru song and Zhao Jing zhu. Ecosystem services and their economic valuation[j]. Chinese Journal of Applied Ecology,1999,10(5) Proc. of SPIE Vol H-6

7 3 Ou yang Zhi yun, Wand Xiaoke and Miao Hong. A primary study on Chinese terrestrial ecosystem services and their ecological-economic s[j]. ACTA ECOLOGICA SINICA,1999,19(5) XIAO Yu, XIE Gaodi and AN Ka. Economic of ecosystem services in Mangcuo Lake drainage basin[j]. Chinese Journal of Applied Ecology, (5): Proc. of SPIE Vol H-7