Biodiversity during Pre and Post Hula Valley Drainage: History
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Ecosystem fertility is dependent on nutrient and water availability which are the drivers of the system of production. The anthropogenic and natural maintenance of ecosystem products such as biodiversity, species richness, agriculture, recreation or eco-tourism is significantly affected by management. The appropriate management might be natural, without human intervention, or anthropogenic, or a combination of both. The management of the Hula Valley, a part of the Lake Kinneret drainage basin, represents an integration of human and natural dependence.

  • Hula
  • drainage
  • reclamation
  • biodiversity index
  • species richness

1. Introduction

Ecosystem fertility is dependent on nutrient and water availability which are the drivers of the system of production. The anthropogenic and natural maintenance of ecosystem products such as biodiversity, species richness, agriculture, recreation or eco-tourism is significantly affected by management. The appropriate management might be natural, without human intervention, or anthropogenic, or a combination of both. The management of the Hula Valley, a part of the Lake Kinneret drainage basin, represents an integration of human and natural dependence. The involvement of climate conditions recently became critical. The hydrological extremism resulting from climate change is ranged between water scarcity and profusion. Therefore, the integration between key factors of the economic benefits of agricultural crop production, and protection of the Kinneret’s water quality and biodiversity, is crucial for the management design of the Hula Valley. The availability of nutrients controls the production of the Hula Valley ecosystem whilst a significant part of the nutrient sources are external and they are transported by water.

2. Geology and Hydrology

The Kinneret drainage basin area is 2730 km2 of which the Hula Valley is about 200 km2. The major water source feeding Lake Kinneret’s headwaters is the rocky karst springs of Mount Hermon. The area of the Mount Hermon range (789 km2) is an uplifted massif of Jurassic and Lower Cretaceous limestone comprising the highest altitude (peak 2814 MASL) of the watershed. The central part of the drainage basin, the Hula Valley (70–90 MASL), is covered by deposited sediments 1000–1500 m in thickness. The water input into Lake Kinneret comes through three major headwater rivers, the Hatzbani (Snir), Banyas (Hermon), and Dan, and several other smaller rivers merging into one as the River Jordan and crossing the Hula Valley. The Jordan contributes about 65% of the Kinneret water budget. Until the mid-1950s the Hula Valley was covered by the shallow old Lake Hula and swampy wetlands. During the 1950s, the Hula Valley was drained and converted into arable land suitable for agricultural development. Lake Kinneret is located below sea level in the northern part of the Syrian-African Graben in northern Israel. The Hula Valley is part of the Lake Kinneret watershed which significantly affects Lake Kinneret’s water quality. Kinneret, the only natural freshwater lake in Israel, is a body of water with multipurpose utilization: water supply, fishery, recreation, and intra- and international tourism. The ecological relationship between the Hula Valley and Lake Kinneret is of national and international concern. The climate of the Kinneret drainage basin is sub-tropical, where the winter is short, wet, and cold and the summer is long, dry, and hot. The rainfall regime in the catchment varies between 900 mm/y in the north and 500 mm/y in the southern part. Lake Kinneret’s waters are conveyed along 130 km from the northern to the southern part of the country for domestic and agricultural supply and underground aquifer recharge. The Lake Kinneret water balance is dependent on climate (rainfall and consequent river discharge), water consumption (pumping withdrawal), and evaporation.

3. Hula Drainage

Prior to the 1950s, the Hula Valley was covered by swampy wetlands and old Lake Hula. Then, the Hula Valley was drained and the ecosystem was modified from a natural wetland habitat to agricultural land use development. Prior to the 1950s, most of this area was not cultivated, malaria was common, and water loss by evapotranspiration was significant. The anxious search for agricultural income resources and assurance of the national water supply in the northern part of the newly created state of Israel initiated the national project of the Hula Drainage. The implementation of this project has been accompanied by research and monitoring of the ecological trait aimed at crop harvest improvement. Forty years after drainage and agricultural development, it has seen inappropriate irrigation and cultivation methods and enhanced deterioration of the peat soil quality, accompanied by heavy dust storms, subsidence of the soil surface, blocking of drainage canals, underground fires, and rodent (Microtus socialis) outbreaks. Consequently, the Hula Reclamation Project (HRP) was implemented (1994–2006). Before the drainage, nitrogen was flushed from the Hula Valley downstream into Lake Kinneret, which was mostly ammonium, and after the drainage, it was modified to nitrate due to peat soil oxidation. Domestic and dairy raw sewage produced by local residents was removed from the Kinneret inputs, stored in reservoirs, and reused, and fish ponds in the valley were restricted from 1700 to 3.5 ha. The hydrological system and irrigation method over the entire valley was modified. The implementation of the HRP resulted in a successful 70-year (1953–2023) mega-ecological-agricultural anthropogenic project in the Hula Valley and the biotic natural species richness was changed. Moreover, eco-tourism has been established by the creation of the shallow Lake Agmon-Hula and open uncultivated fields around, enabling optimal regulation of visits by the public and in particular bird watchers. Pollutant effluents from Lake Agmon-Hula were found to be minor. That infrastructure has attracted numerous bird flocks followed annually by thousands of recreational and bird-watching visitors. Income for the landowners has improved whereas costly maintenance for crop protection required partial deportation of the damaging migratory birds. The Hula drainage and the HRP are two of the greatest ecological projects carried out in Israel since the late 1950s. The Hula Project involved enhanced collaboration between nature authorities, water managers, landowners, regional municipalities and nature conservationists. As part of the nature conservation achieved after the Hula drainage, a comparative evaluation of the biotic species richness of the ecological community in the Hula Valley was carried out. Species richness is also considered as species diversity. In fact, the Hula Valley ecosystem is a constructed wetland including natural and anthropogenic components. Therefore, its maintenance depends upon the cooperation between farming, nature conservation and water quality protection, and monitoring continuity in this fragile ecosystem is imperative.
The Hula drainage and the Hula Reclamation Project implementation created an increase in variable ecological habitats, where terrestrial and semi-aquatic local ecosystems are included. Enhancement of food (prey and foraging) sources attracted birds and mammals into the Hula valley. The implementation of the HRP enhanced the stopover of migratory birds and roosting in Lake Agmon-Hula, and attracted the aquatic foragers nutria. Nevertheless, the use of agricultural crops (peanuts and others) as crane food and the daily feeding of unlimited corn seeds are costly, which requires compensation arrangements. The ecological establishment of such a mega project as the Hula drainage requires a risk assessment for nature. Crane feeding might also attract unwanted birds such as starlings and ravens. Crop damage by cranes was integrated within the administrative frame of the Hula valley management. Fish were introduced which might be attractive for pelicans and cormorants but are potentially damaging for aquaculture and Lake Kinneret fisheries. Moreover, it is not impossible that crane feeding will cause a change of migration route behavior and eco-tourism management might be unaffordable.

This entry is adapted from the peer-reviewed paper 10.3390/d15060758

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