Impact of residential settlements on the life supporting capacity of Har HaNegev arid environment
Lead Authors: Prof. Moshe Shachak, Dr. Miri Tsalyuk (BGU)
Contributors: Arnon Karnieli, Daniel Orenstein, Ehud Meron, Yehoshua Shkedy, Asaf Tsoar
Dryland ecosystems are facing grand challenges of adaptation and reorganization in response to anthropogenic climate and land use changes worldwide [1-3]. While the consequences of human residential development as a major land use change on ecological systems have been studied [4-6], the effect of settlements on the fragile arid environment on the various levels of ecological organization and landscape scales is not well understood.
Israel is one of the densest countries in the world, with the largest birth rate among the developed countries . The fast population growth rate in the country drives an increasing pressure for rapid residential development. The Negev, the southern arid part of Israel, is the largest land resource of the country, and government policy encourages redirecting growth to this region. Therefore, residential development is predicted to expand to this area; it is crucial to understand the effect of such settlement on the ecological integrity of the system.
The Negev highland (Har HaNegev, HN) is an arid environment limited mainly by water availability. It has a mean annual rainfall of 80-100 mm, and mean annual temperature of 18°C (-4°C – 40°C) . Patterns of precipitation and redistribution of rainfall water drives ecosystem functions such as primary and secondary productivity and decomposition. The system is characterized by high topographic, geologic, geomorphic, and pedologic diversity (geodiversity). The geodiversity further interacts with the biodiversity to create Hydro-Geo-Eco-Systems. HN has impressive biodiversity with many unique and endemic species. The high abiotic (Geodiversity) and biotic diversity of the system that provide a bundle of ecosystem services, has attracted human to settle HN since early times. Creation of habitat for species, and existence value of biodiversity are the main ecosystem service of HNPA, which further supports cultural services, including educational activities, research, recreation, and tourism.
HN experiences multiple competing land uses in including residence, mining, agriculture, grazing, tourism, and recreation; army training also has a considerable impact. Har HaNegev Protected Area (HNPA) covers an area of about 1107km2. The multitude of competing land uses, particularly settlements, are the most pressing driver of change to the ecological integrity of HN. Urban and rural residential development imposes pulse and press changes on HN. The pulse event is the settlement establishment, while the press is the continuous interactions between the settlement and the biophysical environment. The impact of development on the ecosystem also includes the disturbances radiating from them; including land cover change, pollution, noise, and artificial lighting. Furthermore, infrastructure and roads connecting the settlements, and the output they produce: sewage, waste, animal manure, increase their damage. Economic activities further drive land use change around settlement.
Within the HN are three small towns, 13 rural settlements, and about 30 homesteads. These homesteads make a living from small scale farming, wineries, grazing, and tourism . The Negev is also home for semi-pastoral Bedouins. In HN, the Bedouin live in small family communities, and their economic activities include sheep and goat herding, manual jobs and tourism. While all these types of settlements have considerable effect on the biodiversity and the ecological integrity of HN, these effects and ways to mitigate them are not well understood [9-13].
Earth observation (EO) systems are especially useful to understand the effect of land use pressure on the ecological integrity of HN. A major goal of HNPA project is to develop tools to use EO in arid environment in order to track changes in biodiversity, ecosystem dynamics, and ecosystem services provisioning, driven by land use changes.
It is crucial to understand the effects of settlements on the life supporting capability of HNPA. This research will provide evidence to guide future development, and guide local regional planning of settlements in the area. In addition, better understanding of settlement-landscape relationship will improve the current management of protected areas and biodiversity.
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