The Ecological Corridor
An ecological corridor is a unique strip of land in possession of particular features (different to those of its surroundings) that forms a link between areas sufficiently large to enable the existence of various kinds of wildlife in their natural habitats which are otherwise disconnected. Ecological corridors connect nature reserves with areas of ecological importance, enabling species to move between them.
These definitions were first established in connection with the landscapes of England and other western European countries. With time the concept of ecological corridors has developed and expanded and today ecological corridors include agricultural lands and natural open spaces that connect nature reserves.
In Israel ecological corridors have great significance. At first, the concept of nature preservation in Israel stemmed from a desire to protect areas of interest and uniqueness in terms of botany, zoology, aquatic life and other aspects and the locations of nature reserves in Israel were determined accordingly. In the early years of the state, nature reserves were also surrounded by nature; they were sufficiently distant from population centers and infrastructure to ensure their protection from nuisances and danger. Over the course of time the population of the country grew and the developed and built-up areas have expanded. Developed lands have inched closer to the borders of nature reserves, becoming a threat to these small sealed-off islands of nature that are surrounded on all sides by residential and industrial zones. Likewise, agricultural plots, cultivated with intensive fertilizer and insecticide use have also damaged the natural conditions.
In this way nature reserves became small, fragmented and isolated islands. This situation has a direct negative effect on the renewal of species: when there is no contact between populations in various areas and no procreation between them, there can be no transfer of genetic material. This results in a decrease in genetic variety; the species atrophy and become increasingly susceptible to threats and outside dangers (Meffe & Carrol, 1997). The limited dimensions of nature reserves in Israel, which allow for the existence of only small populations, worsen this problem - a small, isolated population has no future in the long term and is doomed to extinction. Therefore, protection of open spaces surrounding typical natural areas - both nature reserves and others - is of the utmost importance. These include agricultural lands defined as ecological corridors.
The idea of creating a system of ecological corridors in Israel was first developed by the Nature and Parks Authority (Shkedi & Sadot, 2000). These corridors will connect “statutory protected areas and the open areas between them” in order to support preservation of nature in Israel. The designated aim is to preserve, as much as possible, the spaces within the area of the corridor and to ensure that development takes place outside of the corridor. The concept of ecological corridors that has developed in Israel refers to large strips of land, including mainly natural undeveloped areas, in which the nature reserves are concentrated, connected by strips of man-planted forests and agricultural plots, which enable movement (of animals and seeds) between these natural areas.
The map of suggested ecological corridors demonstrates that the lands included within the system of corridors are mainly open spaces connecting nature reserves and national parks included in National Outline Plan 8 for Nature Reserves, man-planted forests and natural groves of various kinds included in National Outline Plan 22 for Forests and Forestation, in addition to open spaces that are not protected. It contains hardly any large or continuous sections of agricultural land.
Indeed, the flat plains on which agricultural lands are located, among them the Jezreel Valley, the Zebulun Valley, the Sharon and the coastal plain, the Pleset coastal region (including Ashkelon and Ashdod) and the north western Negev and the Beer Sheva Valley, for the most part have been excluded from the arrangement of ecological corridors. This separation between ecological corridors and agricultural lands, and the latent potential of the latter within the arrangement of ecological corridors, raises the possibility that the time has come to construct a system of links between them.
This opinion is based on the concept that agricultural lands can form a central link in the chain of ecological corridors in Israel. In fact, this constitutes a return to one of the principal ideas that led to the development of the concept of ecological corridors - they are strips of agricultural land including natural elements, for example hedgerows, which serve as a passage and shelter for animals and vegetation. It is important to remember that an ecological corridor should possess different qualities to its close surroundings, and that materials and information that flow between natural areas should be concentrated within it.
In accordance, agricultural lands can be discussed on two levels:
The first level refers to linear-oriented elements within the agricultural land that sustain particular qualities, different from those in the surrounding area. In other words, short ecological corridors. The sections that fit these criteria within agricultural areas are likely to be the routes of streams, canals and various fences and hedgerows.
The second level discusses the agricultural land in its entirety, as performing particular functions that separate it from neighboring lands and allowing the movement of animals and seeds: as a long ecological corridor.
This project examines the possibilities of establishing ecological corridors in the Harod valley, between the Gilboa and the slopes of the Tsevaim region. The Harod valley forms part of the national “rift” between the natural mountainous regions in the north and south. This rift includes the agricultural areas of the Jezreel and Harod Valleys, and the approach to the Beit Shean Valley. This project seeks to identify ways to connect the northern and southern mountainous sections by creating ecological corridors that pass through these agricultural areas.
The Harod Ecological Corridor, between the Gilboa and the Tsevaim Heights: A Link in the National Chain of Ecological Corridors.
The ecological corridor within the Gilboa region and the Tsevaim Heights forms part of the national chain of ecological corridors (according to the outline drawn up by the Nature and Parks Authority).
Within the framework of this project, long ecological corridors including agricultural lands will be designated. The planning in the GilboaTabor Stream region will take into account local agricultural areas, their potential passageways, natural areas and the possibilities of connecting between them.
This project will identify local possibilities for connecting natural areas within the lands of the agricultural rift, by highlighting passages and specific corridors within the agricultural area.
These passageways should merit special attention:
Cultivation of natural vegetation along the entire length of the corridors.
Providing the opportunity for comfortable shelter and passage within these corridors, through the creation of resting points and protection for animals.
Reducing the intensity of agricultural cultivation, including a decrease in, or indeed total avoidance of, the use of pesticides and other chemicals.
Planting trees and vegetation that encourage conditions suitable for the existence of animal populations in the ecological corridor.
Location and Borders
This project focuses on an area in the Lower Galilee region, on the approach to the Beit Shean Valley. The planning area has a rural and agricultural character and includes many population centers dating back to the first days of the Jewish settlement of the land, especially in the Harod Valley. In the eastern part of the area is the city of Beit Shean and around it the villages of the Beit Shean Valley. The area includes a number of large streams, the mountainous Tabor, Issachar and Bazak streams, in addition to the Harod Stream and its tributaries that pass through the area, at the heart of the agricultural lands.
The Harod Valley “continues” the Jezreel Valley eastwards, towards the Beit She’an Valley. The water divide between the two valleys lies east of Afula, between the Harod and Kishon streams, and is almost invisible to the naked eye. Since both the Harod and Jezreel valleys are flat, they have been subject to agricultural cultivation for generations.
The agricultural plots that extend Project Location north-east and south-west divide the two parts of the mountainous region, the slopes of the Tsevaim region, the Alonim Hills and Shefaram in the north and the Gilboa, the Shomron and the Carmel in the South.
The national map of ecological corridors designated a connection between these two sections. The detailed map suggests two wide passages, including a large part of the Harod Valley.
Starting Point - The Basis for Alternatives
Figure 1, a schematic map, provides a basis for proposals of various alternatives. Using this map it is possible to identify principal opportunities:
Routes of the major streams that flow from west to east: Tabor, Yissachar, Harod and Bazak streams.
Connectivity - to a certain extent forced, While connectivity on the east-west route, in the form of the major streams and their surroundings, is relatively good, there exists a rift on the north-south route, between the slopes of the Tsevaim region and the Gilboa, in the form of the agricultural land of the Harod valley. This rift is becoming more severe as a result of various land uses and the infrastructure for Road 71 (in addition to the train tracks which are to run parallel to this road in the future), fisheries and the concentration of population centers in the valley and on its edges. The north-south rift is part of the greater disconnection between the mountainous regions of the Galilee in the north and Samaria in the south. Bridging this rift is the central aim of this project. It is possible to suggest two basic alternatives for ecological corridors on the north-south route, based on the existing arrangement:
concentration of efforts on a number of defined routes
spreading of efforts - optimization of the full range of possibilities in the valley.
yet necessary, from north to south, following the routes of the minor streams and dirt paths between the slopes of the Tsevaim region and the Gilboa, crossing Road 71.
The routes of the major streams will constitute an ecological corridor under each one of the proposed alternatives. They are the outline upon which the distribution and flow of species in the entire area relies. The major streams sustain natural areas which are very different to their agricultural surroundings. The proposed alternatives concern the routes running from north to south. Here no clear differences are to be found: the natural areas between agricultural lands are narrower and limited to the routes of minor local streams, tributaries of the Harod stream and roads/paths separating fields and orchards.
While connectivity on the east-west route, in the form of the major streams and their surroundings, is relatively good, there exists a rift on the north-south route, between the slopes of the Tsevaim region and the Gilboa, in the form of the agricultural land of the Harod valley. This rift is becoming more severe as a result of various land uses and the infrastructure for Road 71 (in addition to the train tracks which are to run parallel to this road in the future), fisheries and the concentration of population centers in the valley and on its edges.
The north-south rift is part of the greater disconnection between the mountainous regions of the Galilee in the north and Samaria in the south. Bridging this rift is the central aim of this project.
It is possible to suggest two basic alternatives for ecological corridors on the north-south route, based on the existing arrangement:
concentration of efforts on a number of defined routes
spreading of efforts - optimization of the full range of possibilities in the valley.
Preservation and Development of Natural Elements in the Area and Prevention of Obstructions and Hazards
Nurturing the Streams and Water Quality
The streams constitute the natural routes at the heart of the agricultural area. By nurturing them - including distancing the spraying of pesticides from their vicinity, implementing reseeding and cultivation of natural vegetation, preserving the continuity of the routes and their importance for run-off water from the fields, while at the same time preventing the dumping of waste water into them - we will be able to strengthen the central natural role of the streams as pillars of the ecological corridor.
Preservation of the Edges of the Fields and Roads as Areas Free from Pest Control or Cultivation Research has demonstrated that the edges of roads and fields have the potential to sustain a wide ecological variety in comparison to their surroundings. A greater number of these areas, each sustaining a wider ecological range, raises the value of the region as a whole from an ecological perspective.
Preservation of Natural Areas: Statutory and Other Means
The ecological corridor is comprised of areas with varying natural values. These natural lands constitute a link of significant ecological importance in the route. Within the cultivated valley any rocky land that is not suitable for agricultural use should be left in its natural state or planted with forest. These lands should be protected from pesticide use and any other hazards and in addition by law (preventing the incursion of infrastructures or development).
The Contribution of Water Sources to Ecological Corridors
Migrating birds and other animals passing through the ecological corridor require available water sources and food throughout the year. Accessible water sources should be identified and included within the ecological corridor, as a magnet to attract animals and birds to the valley, with proper agreement and co-operation from local communities.
Pesticides and Pest Control
The spraying of agricultural crops with pesticides affects the natural areas at the edges of the fields and damages the quality of the agricultural land as a passage for animals. The village of Sdeh Eliyahu, in the borders of the planning area, utilizes environmentally friendly agriculture. Encouragement of this kind of endeavor, and widening its implementation, will generate a large space in which agricultural and natural lands are integrated and together support the ecological system.
Waste at the Edges of Fields
Agricultural waste, abandoned pieces of equipment, packaging of pesticides strewn around the edges of the fields: all these constitute dangerous traps for animals in the areas with the highest potential to serve as ecological corridors. Waste must be collected and removed from the corridor. It is possible to co-operate with local communities on this: school children, youth movements and even prison convicts could take care of the land, maintain it and keep it free from poisonous traps and waste.
Natural Vegetation at the Sides of the Roads
The sides of the roads can potentially strengthen the ecological corridor in two ways: by providing shelter and resting places for animals, and by helping to overcome the rift created by the road. They can ensure the existence of a linear natural environment, long and continuous, connecting different land uses. Cleaning and clearing the sides of the road from natural vegetation creates a large area of no value - agricultural or natural- that damages the continuity of the ecological corridor.
Passages: Above and Underground
In order to ensure that the ecological corridors function properly it is necessary to develop passages for animals over and under the traffic infrastructures that cross the corridor. It is important to develop specific passageways, intended for animals alone as much as possible. Opportunities for creating such passages arise each time that a road is built, or an existing road widened or improved.
The passageways for water to flow under Road 71, which cuts across the width of the Harod Valley, prevent flooding of the road and aid the passage of vegetation and animals (apart from large mammals) in a continuous and safe fashion from both sides of the infrastructure line. However, in many cases the passage is full of sediment. This sediment build-up must be removed and the passage maintained as an open space large enough to allow the movement of animals.
Expansion of Population Centers and Development Plans
In the early stages of planning it is possible to influence the character of development in terms of direction, distance from streams or natural areas and contribution to the route of the corridor.
Fences obstruct free movement by animals in the area as a whole and in particular within the ecological corridor. The level of obstruction varies in relation to the type of fence, its size and position. In the planning area fences enclose groves, tree planting lands belonging to the KKL and pastures. The necessity of the fences should be re-examined and if possible alternative measures suggested. In addition, the type of fence used and the possibilities of creating passageways, possibly selective, for certain types of animals should be investigated.
Within the area of the ecological corridor electricity pylons should be isolated in order to reduce the death of birds from electrification. There is a wealth of knowledge on this subject and technical solutions have already been implemented at a number of locations in Israel through the co-operation of the Nature and Parks Authority and the Electricity Company.
Agricultural structures must be built in accordance with the guidelines in National Outline Plan 35, which includes within its remit most of the valley’s area. The building of structures close to the route of the corridor and remaining natural areas, such as the streams, must be constructed with reference to environmental guidelines, minimizing damage to the continuity of natural lands and their character.
Vegetation along the Banks of the Streams
The development of protected routes for the movement of animals requires protection or rehabilitation of the vegetation along the routes of the streams which provides shelter and nesting places. In addition, species indigenous to Israel, such as the common giant reed, act as bio-filters, reducing the amount of nutrients concentrated in the water which can lead to eutrophication. Likewise, developed vegetation along the banks of a stream can prevent the incursion of invasive plants that take control of the banks.
Implementation of a policy to develop the vegetation along the banks of streams requires co-operation with drainage authorities, which customarily remove vegetation form the banks of streams in certain locations on an annual basis.