GIS for Environmental Management along the Central Asian Rivers Tarim and Naryn

Transcription

1 GIS for Environmental Management along the Central Asian Rivers Tarim and Naryn Florian Betz 1, Ümüt Halik 1,2, Bernd Cyffka 1, Alishir Kurban 3, Akylbek Chymyrov 4, Ermek Baibagyshov 5, Jianli Ding 2 1 Catholic University Eichstaett-Ingolstadt, Faculty of Mathematics and Geography, florian.betz@ku.de 2 Xinjiang University, Key Laboratory of Oasis Ecology, uemuet.halik@xju.edu 3 Xinjiang Institute of Geography and Ecology, Chinese Academy of Science, alishir@ms.xjb.ac.cn 4 Kyrgyz State University of Construction, Transport and Architecture, akylbek.chymyrov@aca-giscience.org 5 Naryn State University, nsu0896@yahoo.de Abstract In the Central Asian drylands, the floodplains of the large endorheic rivers have an enormous ecological importance. They are a regional hotspot of biodiversity and provide valuable ecosystem services to the people. But they are heavily endangered by anthropogenic influences like the overexploitation of water resources, intensive agriculture or overgrazing by pastoral use. Nevertheless, up to now, there is no systematic monitoring of the riparian ecosystems as a basis of sustainable environmental management. Against this background, we present the project Ecosystem Assessment and Capacity Building for Sustainable Management of Floodplains along the Central Asian Rivers Tarim and Naryn where we develop methods for monitoring these ecosystems based on an integration of terrestrial survey, remote sensing and GIS techniques. Furthermore, we present a capacity building approach improving the local research capacities and contributing to a more sustainable application of the project results. Keywords: Ecosystem Services, GIS, Remote Sensing, Capacity Building, Tarim, Naryn 1. Introduction In the Central Asian drylands, the large endorheic rivers and their floodplains have an enormous ecological importance. They are not only a regional hotspot of biodiversity, but provide also a wide range of ecosystem services to local people. Among these are the mitigation of sand and dust storms, the storage of carbon as well as the provision of pastoral land, fuel wood and harvestable fruit (Thevs, 2011; Cyffka et al., 2013). Despite this importance, the Central Asian floodplains are heavily endangered or partly even already destroyed by anthropogenic influences. Such influences are the overexploitation of water resources, intensive agriculture or overgrazing by pastoral use (Thevs, 2011). Nevertheless, there is no systematic monitoring of riparian ecosystems with their functions and services. Furthermore, there is commonly no sufficient education of students and young scientists especially regarding the topics of modern GIS and remote sensing technology as well as the interdisciplinary field of ecosystem services. Against this background, we started the project Ecosystem Assessment and Capacity Building for sustainable Management of Floodplains along the Central Asian Rivers Tarim and Naryn (EcoCAR) founded by the German Volkswagen Foundation. Within this project, we develop methods for a monitoring of floodplain ecosystems and their services in two investigation areas at the Tarim in Xinjiang/NW China and the Naryn, Kyrgyzstan. GIS and remote sensing play an important role in this approach. For many environmental issues, the spatial context is important and on remote sensing is probably the only way to get continuous data on a regional scale. Nevertheless, to some degree the education in these topics is often not sufficient in Central Asia. Especially the integration of ecological knowledge, field work with GIS and remote sensing is underdeveloped.

2 In this paper, we demonstrate based on the example of carbon storage at the lower reaches of the Tarim River how we integrate field work, GIS and remote sensing for assessing ecosystem services of floodplain forests. Furthermore, we describe how capacity building for young scientists on the master and PhD level can contribute to a more sustainable development of the riparian ecosystems in Central Asia. 2. Study Areas at the Tarim and the Naryn EcoCAR is working in two investigation areas. One is at the lower reaches of the Tarim River, the other at the middle reaches of the Naryn River in Kyrgyzstan (see also figure 1). The two rivers are quite different, even if their headwaters are directly neighbored. Figure 1: The Investigation Areas at the Tarim and Naryn The middle reaches of the Naryn River are characterized by a very dynamic braided river system with near natural flow conditions. Tectonic uplift lead to an incision of the river channel with the consequence of a very narrow active floodplain. The correspondent ecosystem is dominated by Populus and Salix species as well as the sallow thorne Hippophae rhamnoides. People use trees and shrubs as fuel wood and collect the fruits of the sallow thorn for private use and local markets. Furthermore, the floodplain forests serve as pasture for the livestock. Beside these provisioning ecosystem services, the vegetation also helps mitigating fluvial erosion of the river banks, also important to maintain stable floodplain ecosystems. Main environmental stressor in this area is the intensive use of the riparian forests for woodcutting and livestock grazing leading to a partial degradation. The investigation area at the lower reaches of the Tarim River is characterized by an extremely arid climate with almost absent precipitation. Consequently natural ecosystems

3 depend completely on the water resources of the Tarim and form a green corridor along the river. These so called Tugai forests are mainly composed by Populus euphratica and Tamarix spp. (Aishan et al., 2013). These forests protect the National Highway 218 connecting Xinjiang with Inner China against drifting sand (Cyffka et al., 2013). The trees shelter the soil surface, so only a certain share of the wind force can act onto the ground and mobilize sediment. Additionally, a huge amount of carbon is stored in the main species Populus euphratica, carbon which cannot contribute to the global climate change and its negative consequences (Thevs et al., 2012; Cyffka et al., 2013). 3. Case Study: Modelling Carbon Storage at the Tarim River One valuable example for demonstrating the assessment of ecosystem services based on integrating field work, GIS and remote sensing is carbon storage in floodplain forest in the lower reaches of the Tarim River. We start with the measurement of tree height and diameter at breast height for all Populus euphratica in a monitoring plot together with the coordinates of the trees. This data is brought to a GIS data base. In a second step, we calculate the biomass for each location based on statistical formulas (Chen and Li, 1984; Thevs et al., 2012). Now, we take the point values and rasterize them to a grid with 30 m resolution and correlate them with the corresponding Landsat NDVI values. Afterwards, we apply the resulting exponential equation to a NDVI raster of the whole lower reaches of the Tarim River and summarize the results (figure 2). In a final step, we transform the biomass values to carbon storage based on a conversion factor of 0.5 as suggested by the IPCC (2006). Figure 2: Results from modelling the biomass a the lower Tarim River: a is the biomass map, b is the fitted regression between NDVI and biomass, c gives the values for biomass and carbon storage for the whole lower Tarim (as shown in fig. 2a) The first obvious result is, that biomass is concentrated along the river course. This is due to the fact, that Populus depend on bare surfaces with sufficient soil moisture for germination, conditions only found directly along the river channels (Kuba et al, 2013).

4 Furthermore, the groundwater level increases with increasing distance to the river. Above a certain threshold, the distance is too big and the trees cannot reach the phreatic zone anymore. As phreatophyte, Populus euphratica cannot sustain without connection to the groundwater (Kuba et al., 2013; Thomas, 2014). Summarizing, we get a total value of 1106 x 10 3 tons of stored carbon for the whole lower reaches of the Tarim River. Making a (monetary) valuation of carbon storage as ecosystem service as a consequent step is a difficult task. One approach is the assumption of avoided damage costs (Spangenberg and Settele, 2010). Emitted carbon would cause worldwide damages by extreme weather events or rising sea level. Avoided carbon emission can avoid these damages. One estimation of the value for this is 87 US$ per ton of carbon (Tol, 2009). This would result in a value of about 96.2 million US$ for the carbon storage at the lower reaches of the Tarim River. Nevertheless, this number is a hypothetical value and more useful as a metaphor than a basis for economic calculations (Noorgard, 2010). 4. Capacity Building in EcoCAR To foster a sustainable implementation of the project results we explicitly do not only focus on the development of recommendations for decision makers. Rather, the local capacity for carrying out research and monitoring about the floodplains and its ecosystems is built up by training young scientists in modern approaches and methods. All in all three workshops and one summer school are the platform for teaching students on the master and PhD level in thematical and methodological know-how. This includes the fundamentals of the idea of ecosystem services and its interdisciplinary approach integrating an ecological and socio-economic perspective. Furthermore we focus on a training of modern GIS and remote sensing methods as many environmental issues can only be seen in theirs spatial context. Here, we stick to open source products like e.g. QGIS to give the students the opportunity to apply the software also outside university for practice as well as maybe afterwards as decision makers. Probably even more important than the training in the workshops and the summer school is the joint project work. There, students from Kyrgyzstan, China and Germany work together hands on on the same topic. This form of direct cooperation is the best opportunity to exchange know-how and ideas in an informal way directly among students. Figure 3:Capacity Building: Introduction to GIS at the Naryn State University (l) and joint field work in the Taklamakan Desert (r) This approach together with the inclusion of stakeholders fosters the application and further development of the EcoCAR management suggestions. Therefore, Capacity Building is one of the central goals of our project.

5 5. Towards a better environmental management of riparian areas in Central Asia In this paper, we demonstrated the importance and challenges of a sustainable management of floodplain forests and their ecosystem services in Central Asia. Considering the fact, that there is no sufficient monitoring for this in the moment, we develop a framework for the assessment of floodplain forests and their services (figure 4). Based on classical field work, ecosystem structures are investigated. Together with socio-economic work assessing local peoples demand for natural resources, information about ecosystem functions and services on a local scale is gained. In this step, Geoinformation technology serves mainly as a tool for analyzing the spatial configuration of ESS, often important for understanding environmental issues. Figure 4: Framework for an assessment of floodplains and their ecosystem services applied in the EcoCAR Project In a next step, remote sensing is used for assessing the ecosystem structure on a regional scale like the provision of landcover maps. With this input and the data from the terrestrial ecological and socio-economic investigation, GIS based models for ecosystem services are developed. Based on these models and the discussion with local stakeholders, recommendations for a more sustainable floodplain management are given. But, all these recommendations will not be useful if there are no well-educated people for the implementation. Therefore, the capacity building with the integration of young scientists or students is a crucial point. Only recommendations or workshops for decision makers are unlikely to change things. But in a long term perspective, young people can make the difference because: todays students are tomorrows decision makers! With our project Ecosystem Assessment and Capacity Building for sustainable Management of Floodplains along the Central Asian Rivers Tarim and Naryn we can contribute a little to a better education of students especially regarding an integrated view on ecology and socio-economy within the framework of ecosystem services as well as the Geoinformation tools for an effective environmental monitoring.

6 REFERENCES Aishan T, Halik, Ü, Cyffka B, Kuba M, Abliz A, Baidourela A (2013). Monitoring the hydrological and ecological response to water diversion in the lower reaches of the Tarim River, Northwest China, Quaternary International, 311: Chen B H, Li H Q Study on Biomass of natural Diversifolious Poplar Plantations in River Talimu, Xinjiang, Western China. For. Sc. Technol. Xinjiang 3: (in Chinese) Cyffka B, Rumbaur C, Kuba M, Disse M (2013). Sustainable Management of River Oasis along the Tarim River P.R. China (SuMaRiO) and the Ecosystem Service Approach, Geography, Environment, Society, 6(4): IPCC (2006): 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4: Agriculture, Forestry and other Landuse. Prepared by the National Greenhouse Gas Inventories Programme, Eggleston, HS, L. Buendia, K. Miwa, T. Ngara, and K. Tanabe (eds). Institute for Global Environmental Strategies (IGES), Hayama, Japan. Kuba M, Aishan T, Cyffka B, Halik Ü (2013). Analysis between Soil Moisture, Groundwater Level and Vegetation Vitality along two Transects at the lower Reaches of the Tarim River, Northwest China, GeoÖko, 34: Laity J (2008). Deserts and Desert Environments. Oxford: Wiley-Blackwell. Noorgard RB (2010): Ecosystem Service: From Eye-opening metaphor to Complexity Blinder, Ecological Economics, 69: Spangenberg JH, Settele J (2010). Precisely incorrect? Monetising the Value of Ecosystem Services, Ecological Complexity, 7: Thevs N (2011). Water Scarcity and Allocation in the Tarim Basin: Decision Structures and Adaptations at the local Level, Journal of Current Chinese Affairs, 40: Thevs N, Buras A, Zerbe S, Kühnel E, Abdusalih N, Ovezberdiyeva A (2012). Structure and Wood Biomass of near-natural Floodplain Forests along the Central Asian Rivers Tarim and Amu Darya, Forestry, 85(2): Thomas F (2014): Ecology of Phreatophytes, Progress in Botany, 75: