Pua Bar (Kutiel) | Ben Gurion University of the Negev (original) (raw)
Papers by Pua Bar (Kutiel)
European Journal of Pharmacology, Nov 1, 2013
Israel Journal of Plant Sciences, 2017
Springer Series on Environmental Management, 2013
Two-thirds of the coastal dune area along the Israeli Mediterranean Sea has been lost owing to in... more Two-thirds of the coastal dune area along the Israeli Mediterranean Sea has been lost owing to intensive urbanization and infrastructure development. The remaining dunes are fragmented and only a small part of them have been declared protected. Nizzanim LTER is the largest nature reserve (2,000 ha). Because of low wind velocity in the area, the dunes are experiencing a stabilization process followed by a reduction in the characteristic biodiversity and a shift in desert and psammophilic organisms into characteristic Mediterranean, opportunists and generalists’ species. In order to inhibit the complete stabilization of the entire dunes and to conserve the characteristic biodiversity of the nature reserve, the perennial vegetation was removed from several stabilized dunes in order to reactivate them to a mobile state and to encourage the re-establishment of sand-dwelling organisms. Four years later, the treated dunes are very different from the mobile or semi-stabilized dunes, but are still similar to the stabilized dunes.
Journal of Hydrology, 2008
ABSTRACT Afforestation in arid zones is of increasing importance as it is one of the favored appr... more ABSTRACT Afforestation in arid zones is of increasing importance as it is one of the favored approaches to combat desertification. Rainfall interception by the canopy plays an important role in determining the amount of rainfall reaching the forest floor. The throughfall patterns of coniferous forests planted in arid zones have hitherto not been well documented. The research site in which the measurements were carried out was located within a mature pine forest (Pinus halepensis, Mill) planted in an arid zone (average annual precipitation: 280 mm and annual class-A evaporation pan: 2500 mm). Measurements of precipitation, throughfall, stemflow, soil water content and transpiration were recorded during three years. Canopy cover was estimated from the analysis of hemispherical photographs obtained during the winter. The spatially averaged throughfall, obtained for each event from 20 rainfall gauges installed below the canopy was linearly correlated with gross rainfall and independent of rainfall intensity. We found that the spatial distribution of the throughfall on the forest floor was highly heterogeneous. A fairly consistent distribution of throughfall was evident with some gauges steadily showing a higher percentage of throughfall than others. However, we could not find any relation between the degree of canopy openness (or any other quantifiable canopy characteristic) and the relative throughfall. The spatial pattern of throughfall was however found to be significant when assessed by means of the “K-means Clustering” analysis.The spatial distribution of water in the soil as measured 48 h after rainfall events with a neutron gauge was not correlated to the distribution of throughfall when each of the measuring points was assessed individually. The average throughfall was however well correlated to the average increase in the soil water content and indicates that there is some degree of horizontal water movement (overland or below ground) within the plot.The results presented suggest that point measurements are not the correct tool for water balances of sparse canopy forests and that even for small plots horizontal sampling is of the essence.The practical implication of this study is that it shows that for this particular site a very large fraction of the rainfall reaches the ground and is thus available for plant and/or tree development, a key issue in an area with a rainless period of at least six months during which high pan evaporation rates prevail.
The present special issue of the Geography Research Forum focuses on diverse subjects dealing wit... more The present special issue of the Geography Research Forum focuses on diverse subjects dealing with the human-environment interface in Israel. This issue consists of 7 papers which reflect some of the environmental problems and challenges faced by Israel at present.
Israel Journal of Ecology & Evolution, 2010
Over 50 percent of the world’s population lives in urban areas and affect soil properties. The ai... more Over 50 percent of the world’s population lives in urban areas and affect soil properties. The aim of this study was to analyze soil properties in various urban open land use units (LUU) in two neighborhoods that differ in their socio-economic levels (High and Low). Four types of LUU (municipal parks, private gardens, derelict areas and traffic islands) with four replicas for each LUU were chosen in each neighborhood. Organic matter content, soil moisture and pH at two depths of soil (0-2 cm and 5-10 cm) and soil surface compaction by penetration depth were analyzed. Results indicate that “urbanization footprint” was significantly represented by the upper soil layer. Urbanization led to increase of organic matter and water content in the sandy soil relatively to undisturbed sandy soil that was observed at an adjacent national park. The anthropogenic impact on soil within the urban system is correlated with the socio-economic level of the neighborhood. A low socio-economic level led ...
Modern intensive agriculture is one of the main causes for natural ecosystem fragmentation. The r... more Modern intensive agriculture is one of the main causes for natural ecosystem fragmentation. The relationships between these two, arable land and natural ecosystem land, are distinctly manifested in the contact lines between them, which are the edges. The object of the study was to characterize the biotic and a-biotic properties of the edges and to understand the factors that determine them. The study was conducted in the southern part of the Mediterranean biogeographical region in Israel (300 mm mean annual rainfall). The dwarf-shrub association dominates the natural areas, while Sarcopoterium spinosum is the principal species. These areas are fragmented by cultivated land, which cover about 70% of the area. Twenty-four natural patches in various sizes were selected, and plant observations from the patch center to the edge of each patch were obtained. The results indicated that (a) the species richness was 4 times less rich on the edges than on the patch center, while the Shannon-Wiener species diversity was twice as high (b) Plant composition differs significantly from the edge and the patch center. Grasses such as Avena sterilis dominate the edges (c) Avena sterilis biomass, the number of seeds and their weight and height were significantly higher on the edges than on the patch center (4, 3.3 and 1.5, respectively) (d) soil depth on the edges was about 2.5 times higher than the depth in the patch center, and vice versa for the rock cover. A model, which describes the causes and processes that determine the edge design and properties, is proposed.
Modern agriculture is one of the prime factors in the decrease of biodiversity and landscape hete... more Modern agriculture is one of the prime factors in the decrease of biodiversity and landscape heterogeneity. Additionally, it increases fragmentation of the natural landscape, leaving only remnant patches of the prior habitats. The remaining patches are of major importance as they conserve, in various degrees, the original flora and fauna of the area prior to the disturbance. There are two main theories that explain the flora and fauna composition and the biodiversity in the surviving patches: The "Island Biogeographical Theory" of MacArthur and Wilson (1967) and the "Metapopulation Theory" of Levins (1970). Vast natural areas in semi-arid regions in Israel decreased in area significantly due to intensive agricultural development over the last 50 years. This resulted in fragmented patches of Mediterranean dwarf-shrub land within the heart of the cultivated lands. The Mediterranean dwarf-shrub land is considered one of the most diverse ecosystems in Israel and in t...
Israel Journal of Plant Sciences, 2017
In recent decades, recreational activities in natural open areas have increased substantially. At... more In recent decades, recreational activities in natural open areas have increased substantially. At the same time, stresses imposed upon these areas have increased considerably as a result of a significant reduction in their dimension. These activities strongly affect ecosystem attributes and processes. This paper intends to review several studies that were conducted in one of the protected areas in Israel, Ramat Hanadiv Park, aiming to (a) quantify the rate of pedestrian trail development and (b) examine the impact of high and low trampling intensities on soil and vegetation properties at different trail sections (center, edge and controla natural area adjacent to the trail). The following properties were examined: soil compaction, bulk density, aggregate size distribution, organic matter, moisture, electrical conductivity, pH, sodium and potassium concentrations, vegetation cover, species richness, and composition. The results indicated that: (a) the number of pedestrian trails increased slightly between the years 1944 and 1990; (b) soil properties, except for soil compaction and aggregate size, were not affected by low trampling intensity. A slight decrease in the soil measured properties was recorded at trail centers. However, under high trampling intensity, a reduction in most soil measured properties was detected on all trail sections; (c) vegetation cover, height and species richness were lower at the trail center under high and low trampling intensities. Herbaceous plant species that are common in compacted soils were found under intense trampling impacts. The conclusions from the studies conducted at Ramat Hanadiv Park were: (a) there is a positive correlation between trampling intensities and soil and vegetation properties; (b) an increase in trampling intensity is followed by spatial degradation of soil properties beyond the trail's visible boundaries (what we referred as the "control"); and (c) most of the trails in Ramat Hanadiv Park experience low trampling intensities.
<p>... more <p>In semi-arid and arid environments, clonal plants occasionally appear in ring patterns with a barren soil centre. There is a general agreement that this pattern forms when ramets grow radially, leaving a dead centre where the parent plant once was. Nevertheless, there is still some controversy over the nature of water source-sink relations in and around the rings, and the mechanism that drive the ring formation. We studied Asphodelus ramosus rings in two sites with different soil types (sand and loess) but comparable climate, in order to understand whether differences in soil hydraulic properties create different water source-sink relations and mechanisms that drive ring formation. We characterised soil hydraulic properties and dynamics along the rainy season and during the dry season, accompanied by measurements of soil texture and of belowground storage root biomass. We found that the nature of source-sink relations varies with soil type and properties. In sandy soils, water supply to ring perimeters is mainly from their centre. In loessial soils, water supply to ring perimeters is mainly from the surrounding matrix. Consequently, rings are larger in sandy soils than in loessial soils, in each case in order to optimise water source area. Therefore, studying the formation of rings and other vegetation spatial patterns should consider local soil properties and the possibility that similar patterns may emerge through various mechanisms.</p>
Biological invasion by plants is one of the most upsetting issues for conservation managers. Acac... more Biological invasion by plants is one of the most upsetting issues for conservation managers. Acacia saligna is considered as an invasive plant in the Mediterranean regions of Israel, Turkey, Cyprus, South Africa and Australia. This species produces an immense number of seeds that remain viable for many years, which enables the spread of the species. The aim of this study was to assess the effect of soil-solarization treatments on the viability of A. saligna seeds at four soil depths (0-3, 3-6, 6-9 and 9-12 cm). We analyzed three soil solarization treatments: (i) standard, (ii) intensive and (iii) extremely intensive. The results indicate that temperatures of solarized soil (temperature fluctuations between 35-90°C during 24 hours for 30 days) reduced seed viability completely at all soil depths. Proceedings 10th MEDECOS Conference, April 25 – May 1, 2004, Rhodes, Greece, Arianoutsou & Papanastasis (eds) © 2004 Millpress, Rotterdam, ISBN 90 5966 016 1
Biological invasion by invasive plants is one of the most upsetting issues for conservation manag... more Biological invasion by invasive plants is one of the most upsetting issues for conservation managers. However, very few empirical studies support applicable tools in order to cope with the problem. Studies that evaluate the spreading rate of invasive plants, their impacts on various habitats and the biological invasion consequences on conservation objectives are needed as a basic background for management. The aims of this study were to (a) assess the spreading rate of the invasive plant Acacia saligna in various coastal habitats in Israel, using GIS and remote sensing methods (b) assess the impact of the invasion on the indigenous coastal vegetation. The study was conducted at Nitsanim Sand Park, which is a protected area for coastal landscapes and sand-bound plants and animal conservation objectives. We developed a universal index, the Aggregate Ecological Value (AEV), which takes into consideration the significance of a species for conservation and its abundance within a habitat....
Israel Journal of Plant Sciences, 2017
Coastal sand dunes are susceptible to invasive plants that significantly alter these endangered e... more Coastal sand dunes are susceptible to invasive plants that significantly alter these endangered ecosystems. Acacia saligna is a small Australian tree that has become a significant invasive plant in Israel and in many other Mediterranean countries. The aim of this research was to study the impact of A. saligna on the indigenous vegetation of three coastal habitats (sand dunes, inter-dune depressions, and aeolianite [sandstone] ridges) in the Nizzanim Long Term Ecosystem Research Nature Reserve, Israel. Plant observations were conducted in the spring, in the following site types: (1) sites planted with A. saligna and sites invaded by A. saligna; and (2) reference sites not invaded by A. saligna. A simple index, the aggregate ecological value, was developed in order to evaluate the impact and the ecological value of each habitat and site for conservation purposes. The results indicate that planting A. saligna and invasion by A. saligna changed plant community composition, reduced psammophyte species richness, caused the disappearance of most endemic, rare, and protected species, and overall reduced the ecological value of the Nizzanim Nature Reserve.
Biological Invasions, 2018
Reducing the seed bank of invasive plants is a prerequisite for successful restoration of invaded... more Reducing the seed bank of invasive plants is a prerequisite for successful restoration of invaded ecosystems. The Australian legume tree Acacia saligna is one of the worst invasive plants in Mediterranean climate regions. This fire-adapted species possesses a large persistent seed bank characterized by physical dormant seeds. The present research was aimed to compare the efficacy of prescribed burning, soil solarization by solar heating of moist soil, and their use in combination on A. saligna seed bank reduction, using the buried seed method, and on seedling emergence from the natural seed bank, as a model of controlling fire-adapted plants. The data obtained show that the direct effect of prescribed burning on the buried seed dynamics was highly variable, and it only reduced seed viability from 98% to about 56%. Soil solarization, particularly in combination with prescribed burning, was much more effective than prescribed burning alone, reducing seed viability to about 29 and 4%, respectively. These results were confirmed by recording seedling emergence from the natural seed bank during two successive germination years following the treatments. Only a relatively very small number of seedlings emerged in the soil solarization treatment and none in the combined treatment. Based on the above data, it is recommended to apply prescribed burning as a pretreatment for soil solarization, or to utilize wild fires followed by soil solarization to reduce the seed bank of invasive fire-adapted plants. In situations in which fire cannot be used as a pretreatment, soil solarization alone is reasonably effective.
Biological control theory has long been based on the model of arthropod community structure first... more Biological control theory has long been based on the model of arthropod community structure first proposed by Hairston, Smith and Slobodkin, in which communities are built from three functionally discrete trophic levels (plants, herbivores, predators). Under this model, predator diversity is expected to have a uniformly positive influence on biological control success (i.e., the suppression of herbivore populations). I will describe a case study of a cotton arthropod community whose interactions are fundamentally incompatible with the three trophic level model. Generalist predators in this system eat not only herbivores but also each other. The result is a mixture of 3-and 4-trophic level behavior, and the failure of biological control. I conclude that a deeper understanding of predator ecology is needed to predict predator function, and highlight some recent attempts to understand why some predators function primarily as consumers of herbivores, while others function primarily as c...
Journal of Environmental Planning and Management, 2021
A perpetual lack of adequate resources to conserve and protect nature requires managers to priori... more A perpetual lack of adequate resources to conserve and protect nature requires managers to prioritize some conservation efforts over others. Conservation managers tend to resist prioritization based on one specific goal, preferring to compare the outcomes of conservation programs with the achievement of diverse goals. We describe a conservation index based on a survey of management at the Israel Nature and Parks Authority (INPA). The result provided an index for spatial prioritization of conservation efforts. The surveys revealed a strong preference for conservation attributes that were more relevant in the north of Israel where levels of biodiversity are perceived to be higher. The contribution of this research is to provide an objective method of spatial prioritization not requiring conservation managers to express preferences for one region over another. A second contribution of the research was the revealed differences in prioritization of conservation goals between national INP...
Journal for Nature Conservation, 2020
Using a conservation index as a prioritization tool, we explore combining some protected areas an... more Using a conservation index as a prioritization tool, we explore combining some protected areas and dividing others in order to optimally redistribute rangers when no additional financial resources are available. Then we explore splitting protected areas to achieve the optimal distribution of additional human resources if additional financial resources become available. We found that efficiencies can be achieved by combining ranger areas with low value indices and splitting ranger areas with high value indices thus freeing rangers to move from low valued areas to high valued areas. Another approach to prioritizing conservation resource distribution when budgets are limited is return on investment. Using the index of the ranger area divided by the cost of managing the ranger area, to prioritize where budgets are distributed could provide greater protection at different budget levels over other methods of prioritization. The ROI Index, which measured the per index cost, outperforms mos...
Applied Sciences, 2021
Substantial evidence now suggests that a positive diversity–stability relationship exists. Yet fe... more Substantial evidence now suggests that a positive diversity–stability relationship exists. Yet few studies examine the facets of biodiversity that contribute to this relationship, and empirical research is predominantly conducted on grassland communities under controlled conditions. We investigate the roles of species richness, environmental condition (vegetation cover), asynchrony, and weighted population stability in driving community stability across multiple taxa. We used data from a Long-term Ecological Research project to investigate temporal stability of annual plants, beetles, reptiles, and rodents in Nizzanim Coastal Sand Dune Nature Reserve in Israel. All four taxa had a strong positive relationship between asynchrony and community stability. Only rodents showed a positive richness–stability relationship. Perennial plant cover had a significant relationship with community stability for three taxa, but the direction of the correlation varied. Asynchrony had a stronger relat...
Land Use Policy, 2018
In the last few decades, "natural" open space has been rapidly disappearing, replaced by various ... more In the last few decades, "natural" open space has been rapidly disappearing, replaced by various land uses, such as agriculture, pastureland and cities. This decline in open space, combined with other processes adversely affecting ecosystems and the environment, highlights the importance of natural open spaces protection. Protected areas enable ecosystems to maintain their ecological integrity, thereby safeguarding many important ecological assets and services provided by ecosystems. The aim of this study is to assess the economic value of multiple ecosystem services (ESs) and the tradeoff between them and species richness across different management alternatives at the protected area of Ramat Hanadiv long term ecological research (LTER) Nature Park, in Israel. Ecological data were retrieved from previous research conducted at the nature park, and the valuation of landscape values was performed using the replacement cost method and a contingent valuation survey. The relationship between ES value and species richness was found to be negative. Of all management alternatives studied, only the planted conifer forest alternative was found to be inefficient; moving to other alternatives would enhance ES provision levels and species richness. This research demonstrates a simple path for providing land managers with an ecological data-based tool for comparing management alternatives in monetary terms.
European Journal of Pharmacology, Nov 1, 2013
Israel Journal of Plant Sciences, 2017
Springer Series on Environmental Management, 2013
Two-thirds of the coastal dune area along the Israeli Mediterranean Sea has been lost owing to in... more Two-thirds of the coastal dune area along the Israeli Mediterranean Sea has been lost owing to intensive urbanization and infrastructure development. The remaining dunes are fragmented and only a small part of them have been declared protected. Nizzanim LTER is the largest nature reserve (2,000 ha). Because of low wind velocity in the area, the dunes are experiencing a stabilization process followed by a reduction in the characteristic biodiversity and a shift in desert and psammophilic organisms into characteristic Mediterranean, opportunists and generalists’ species. In order to inhibit the complete stabilization of the entire dunes and to conserve the characteristic biodiversity of the nature reserve, the perennial vegetation was removed from several stabilized dunes in order to reactivate them to a mobile state and to encourage the re-establishment of sand-dwelling organisms. Four years later, the treated dunes are very different from the mobile or semi-stabilized dunes, but are still similar to the stabilized dunes.
Journal of Hydrology, 2008
ABSTRACT Afforestation in arid zones is of increasing importance as it is one of the favored appr... more ABSTRACT Afforestation in arid zones is of increasing importance as it is one of the favored approaches to combat desertification. Rainfall interception by the canopy plays an important role in determining the amount of rainfall reaching the forest floor. The throughfall patterns of coniferous forests planted in arid zones have hitherto not been well documented. The research site in which the measurements were carried out was located within a mature pine forest (Pinus halepensis, Mill) planted in an arid zone (average annual precipitation: 280 mm and annual class-A evaporation pan: 2500 mm). Measurements of precipitation, throughfall, stemflow, soil water content and transpiration were recorded during three years. Canopy cover was estimated from the analysis of hemispherical photographs obtained during the winter. The spatially averaged throughfall, obtained for each event from 20 rainfall gauges installed below the canopy was linearly correlated with gross rainfall and independent of rainfall intensity. We found that the spatial distribution of the throughfall on the forest floor was highly heterogeneous. A fairly consistent distribution of throughfall was evident with some gauges steadily showing a higher percentage of throughfall than others. However, we could not find any relation between the degree of canopy openness (or any other quantifiable canopy characteristic) and the relative throughfall. The spatial pattern of throughfall was however found to be significant when assessed by means of the “K-means Clustering” analysis.The spatial distribution of water in the soil as measured 48 h after rainfall events with a neutron gauge was not correlated to the distribution of throughfall when each of the measuring points was assessed individually. The average throughfall was however well correlated to the average increase in the soil water content and indicates that there is some degree of horizontal water movement (overland or below ground) within the plot.The results presented suggest that point measurements are not the correct tool for water balances of sparse canopy forests and that even for small plots horizontal sampling is of the essence.The practical implication of this study is that it shows that for this particular site a very large fraction of the rainfall reaches the ground and is thus available for plant and/or tree development, a key issue in an area with a rainless period of at least six months during which high pan evaporation rates prevail.
The present special issue of the Geography Research Forum focuses on diverse subjects dealing wit... more The present special issue of the Geography Research Forum focuses on diverse subjects dealing with the human-environment interface in Israel. This issue consists of 7 papers which reflect some of the environmental problems and challenges faced by Israel at present.
Israel Journal of Ecology & Evolution, 2010
Over 50 percent of the world’s population lives in urban areas and affect soil properties. The ai... more Over 50 percent of the world’s population lives in urban areas and affect soil properties. The aim of this study was to analyze soil properties in various urban open land use units (LUU) in two neighborhoods that differ in their socio-economic levels (High and Low). Four types of LUU (municipal parks, private gardens, derelict areas and traffic islands) with four replicas for each LUU were chosen in each neighborhood. Organic matter content, soil moisture and pH at two depths of soil (0-2 cm and 5-10 cm) and soil surface compaction by penetration depth were analyzed. Results indicate that “urbanization footprint” was significantly represented by the upper soil layer. Urbanization led to increase of organic matter and water content in the sandy soil relatively to undisturbed sandy soil that was observed at an adjacent national park. The anthropogenic impact on soil within the urban system is correlated with the socio-economic level of the neighborhood. A low socio-economic level led ...
Modern intensive agriculture is one of the main causes for natural ecosystem fragmentation. The r... more Modern intensive agriculture is one of the main causes for natural ecosystem fragmentation. The relationships between these two, arable land and natural ecosystem land, are distinctly manifested in the contact lines between them, which are the edges. The object of the study was to characterize the biotic and a-biotic properties of the edges and to understand the factors that determine them. The study was conducted in the southern part of the Mediterranean biogeographical region in Israel (300 mm mean annual rainfall). The dwarf-shrub association dominates the natural areas, while Sarcopoterium spinosum is the principal species. These areas are fragmented by cultivated land, which cover about 70% of the area. Twenty-four natural patches in various sizes were selected, and plant observations from the patch center to the edge of each patch were obtained. The results indicated that (a) the species richness was 4 times less rich on the edges than on the patch center, while the Shannon-Wiener species diversity was twice as high (b) Plant composition differs significantly from the edge and the patch center. Grasses such as Avena sterilis dominate the edges (c) Avena sterilis biomass, the number of seeds and their weight and height were significantly higher on the edges than on the patch center (4, 3.3 and 1.5, respectively) (d) soil depth on the edges was about 2.5 times higher than the depth in the patch center, and vice versa for the rock cover. A model, which describes the causes and processes that determine the edge design and properties, is proposed.
Modern agriculture is one of the prime factors in the decrease of biodiversity and landscape hete... more Modern agriculture is one of the prime factors in the decrease of biodiversity and landscape heterogeneity. Additionally, it increases fragmentation of the natural landscape, leaving only remnant patches of the prior habitats. The remaining patches are of major importance as they conserve, in various degrees, the original flora and fauna of the area prior to the disturbance. There are two main theories that explain the flora and fauna composition and the biodiversity in the surviving patches: The "Island Biogeographical Theory" of MacArthur and Wilson (1967) and the "Metapopulation Theory" of Levins (1970). Vast natural areas in semi-arid regions in Israel decreased in area significantly due to intensive agricultural development over the last 50 years. This resulted in fragmented patches of Mediterranean dwarf-shrub land within the heart of the cultivated lands. The Mediterranean dwarf-shrub land is considered one of the most diverse ecosystems in Israel and in t...
Israel Journal of Plant Sciences, 2017
In recent decades, recreational activities in natural open areas have increased substantially. At... more In recent decades, recreational activities in natural open areas have increased substantially. At the same time, stresses imposed upon these areas have increased considerably as a result of a significant reduction in their dimension. These activities strongly affect ecosystem attributes and processes. This paper intends to review several studies that were conducted in one of the protected areas in Israel, Ramat Hanadiv Park, aiming to (a) quantify the rate of pedestrian trail development and (b) examine the impact of high and low trampling intensities on soil and vegetation properties at different trail sections (center, edge and controla natural area adjacent to the trail). The following properties were examined: soil compaction, bulk density, aggregate size distribution, organic matter, moisture, electrical conductivity, pH, sodium and potassium concentrations, vegetation cover, species richness, and composition. The results indicated that: (a) the number of pedestrian trails increased slightly between the years 1944 and 1990; (b) soil properties, except for soil compaction and aggregate size, were not affected by low trampling intensity. A slight decrease in the soil measured properties was recorded at trail centers. However, under high trampling intensity, a reduction in most soil measured properties was detected on all trail sections; (c) vegetation cover, height and species richness were lower at the trail center under high and low trampling intensities. Herbaceous plant species that are common in compacted soils were found under intense trampling impacts. The conclusions from the studies conducted at Ramat Hanadiv Park were: (a) there is a positive correlation between trampling intensities and soil and vegetation properties; (b) an increase in trampling intensity is followed by spatial degradation of soil properties beyond the trail's visible boundaries (what we referred as the "control"); and (c) most of the trails in Ramat Hanadiv Park experience low trampling intensities.
<p>... more <p>In semi-arid and arid environments, clonal plants occasionally appear in ring patterns with a barren soil centre. There is a general agreement that this pattern forms when ramets grow radially, leaving a dead centre where the parent plant once was. Nevertheless, there is still some controversy over the nature of water source-sink relations in and around the rings, and the mechanism that drive the ring formation. We studied Asphodelus ramosus rings in two sites with different soil types (sand and loess) but comparable climate, in order to understand whether differences in soil hydraulic properties create different water source-sink relations and mechanisms that drive ring formation. We characterised soil hydraulic properties and dynamics along the rainy season and during the dry season, accompanied by measurements of soil texture and of belowground storage root biomass. We found that the nature of source-sink relations varies with soil type and properties. In sandy soils, water supply to ring perimeters is mainly from their centre. In loessial soils, water supply to ring perimeters is mainly from the surrounding matrix. Consequently, rings are larger in sandy soils than in loessial soils, in each case in order to optimise water source area. Therefore, studying the formation of rings and other vegetation spatial patterns should consider local soil properties and the possibility that similar patterns may emerge through various mechanisms.</p>
Biological invasion by plants is one of the most upsetting issues for conservation managers. Acac... more Biological invasion by plants is one of the most upsetting issues for conservation managers. Acacia saligna is considered as an invasive plant in the Mediterranean regions of Israel, Turkey, Cyprus, South Africa and Australia. This species produces an immense number of seeds that remain viable for many years, which enables the spread of the species. The aim of this study was to assess the effect of soil-solarization treatments on the viability of A. saligna seeds at four soil depths (0-3, 3-6, 6-9 and 9-12 cm). We analyzed three soil solarization treatments: (i) standard, (ii) intensive and (iii) extremely intensive. The results indicate that temperatures of solarized soil (temperature fluctuations between 35-90°C during 24 hours for 30 days) reduced seed viability completely at all soil depths. Proceedings 10th MEDECOS Conference, April 25 – May 1, 2004, Rhodes, Greece, Arianoutsou & Papanastasis (eds) © 2004 Millpress, Rotterdam, ISBN 90 5966 016 1
Biological invasion by invasive plants is one of the most upsetting issues for conservation manag... more Biological invasion by invasive plants is one of the most upsetting issues for conservation managers. However, very few empirical studies support applicable tools in order to cope with the problem. Studies that evaluate the spreading rate of invasive plants, their impacts on various habitats and the biological invasion consequences on conservation objectives are needed as a basic background for management. The aims of this study were to (a) assess the spreading rate of the invasive plant Acacia saligna in various coastal habitats in Israel, using GIS and remote sensing methods (b) assess the impact of the invasion on the indigenous coastal vegetation. The study was conducted at Nitsanim Sand Park, which is a protected area for coastal landscapes and sand-bound plants and animal conservation objectives. We developed a universal index, the Aggregate Ecological Value (AEV), which takes into consideration the significance of a species for conservation and its abundance within a habitat....
Israel Journal of Plant Sciences, 2017
Coastal sand dunes are susceptible to invasive plants that significantly alter these endangered e... more Coastal sand dunes are susceptible to invasive plants that significantly alter these endangered ecosystems. Acacia saligna is a small Australian tree that has become a significant invasive plant in Israel and in many other Mediterranean countries. The aim of this research was to study the impact of A. saligna on the indigenous vegetation of three coastal habitats (sand dunes, inter-dune depressions, and aeolianite [sandstone] ridges) in the Nizzanim Long Term Ecosystem Research Nature Reserve, Israel. Plant observations were conducted in the spring, in the following site types: (1) sites planted with A. saligna and sites invaded by A. saligna; and (2) reference sites not invaded by A. saligna. A simple index, the aggregate ecological value, was developed in order to evaluate the impact and the ecological value of each habitat and site for conservation purposes. The results indicate that planting A. saligna and invasion by A. saligna changed plant community composition, reduced psammophyte species richness, caused the disappearance of most endemic, rare, and protected species, and overall reduced the ecological value of the Nizzanim Nature Reserve.
Biological Invasions, 2018
Reducing the seed bank of invasive plants is a prerequisite for successful restoration of invaded... more Reducing the seed bank of invasive plants is a prerequisite for successful restoration of invaded ecosystems. The Australian legume tree Acacia saligna is one of the worst invasive plants in Mediterranean climate regions. This fire-adapted species possesses a large persistent seed bank characterized by physical dormant seeds. The present research was aimed to compare the efficacy of prescribed burning, soil solarization by solar heating of moist soil, and their use in combination on A. saligna seed bank reduction, using the buried seed method, and on seedling emergence from the natural seed bank, as a model of controlling fire-adapted plants. The data obtained show that the direct effect of prescribed burning on the buried seed dynamics was highly variable, and it only reduced seed viability from 98% to about 56%. Soil solarization, particularly in combination with prescribed burning, was much more effective than prescribed burning alone, reducing seed viability to about 29 and 4%, respectively. These results were confirmed by recording seedling emergence from the natural seed bank during two successive germination years following the treatments. Only a relatively very small number of seedlings emerged in the soil solarization treatment and none in the combined treatment. Based on the above data, it is recommended to apply prescribed burning as a pretreatment for soil solarization, or to utilize wild fires followed by soil solarization to reduce the seed bank of invasive fire-adapted plants. In situations in which fire cannot be used as a pretreatment, soil solarization alone is reasonably effective.
Biological control theory has long been based on the model of arthropod community structure first... more Biological control theory has long been based on the model of arthropod community structure first proposed by Hairston, Smith and Slobodkin, in which communities are built from three functionally discrete trophic levels (plants, herbivores, predators). Under this model, predator diversity is expected to have a uniformly positive influence on biological control success (i.e., the suppression of herbivore populations). I will describe a case study of a cotton arthropod community whose interactions are fundamentally incompatible with the three trophic level model. Generalist predators in this system eat not only herbivores but also each other. The result is a mixture of 3-and 4-trophic level behavior, and the failure of biological control. I conclude that a deeper understanding of predator ecology is needed to predict predator function, and highlight some recent attempts to understand why some predators function primarily as consumers of herbivores, while others function primarily as c...
Journal of Environmental Planning and Management, 2021
A perpetual lack of adequate resources to conserve and protect nature requires managers to priori... more A perpetual lack of adequate resources to conserve and protect nature requires managers to prioritize some conservation efforts over others. Conservation managers tend to resist prioritization based on one specific goal, preferring to compare the outcomes of conservation programs with the achievement of diverse goals. We describe a conservation index based on a survey of management at the Israel Nature and Parks Authority (INPA). The result provided an index for spatial prioritization of conservation efforts. The surveys revealed a strong preference for conservation attributes that were more relevant in the north of Israel where levels of biodiversity are perceived to be higher. The contribution of this research is to provide an objective method of spatial prioritization not requiring conservation managers to express preferences for one region over another. A second contribution of the research was the revealed differences in prioritization of conservation goals between national INP...
Journal for Nature Conservation, 2020
Using a conservation index as a prioritization tool, we explore combining some protected areas an... more Using a conservation index as a prioritization tool, we explore combining some protected areas and dividing others in order to optimally redistribute rangers when no additional financial resources are available. Then we explore splitting protected areas to achieve the optimal distribution of additional human resources if additional financial resources become available. We found that efficiencies can be achieved by combining ranger areas with low value indices and splitting ranger areas with high value indices thus freeing rangers to move from low valued areas to high valued areas. Another approach to prioritizing conservation resource distribution when budgets are limited is return on investment. Using the index of the ranger area divided by the cost of managing the ranger area, to prioritize where budgets are distributed could provide greater protection at different budget levels over other methods of prioritization. The ROI Index, which measured the per index cost, outperforms mos...
Applied Sciences, 2021
Substantial evidence now suggests that a positive diversity–stability relationship exists. Yet fe... more Substantial evidence now suggests that a positive diversity–stability relationship exists. Yet few studies examine the facets of biodiversity that contribute to this relationship, and empirical research is predominantly conducted on grassland communities under controlled conditions. We investigate the roles of species richness, environmental condition (vegetation cover), asynchrony, and weighted population stability in driving community stability across multiple taxa. We used data from a Long-term Ecological Research project to investigate temporal stability of annual plants, beetles, reptiles, and rodents in Nizzanim Coastal Sand Dune Nature Reserve in Israel. All four taxa had a strong positive relationship between asynchrony and community stability. Only rodents showed a positive richness–stability relationship. Perennial plant cover had a significant relationship with community stability for three taxa, but the direction of the correlation varied. Asynchrony had a stronger relat...
Land Use Policy, 2018
In the last few decades, "natural" open space has been rapidly disappearing, replaced by various ... more In the last few decades, "natural" open space has been rapidly disappearing, replaced by various land uses, such as agriculture, pastureland and cities. This decline in open space, combined with other processes adversely affecting ecosystems and the environment, highlights the importance of natural open spaces protection. Protected areas enable ecosystems to maintain their ecological integrity, thereby safeguarding many important ecological assets and services provided by ecosystems. The aim of this study is to assess the economic value of multiple ecosystem services (ESs) and the tradeoff between them and species richness across different management alternatives at the protected area of Ramat Hanadiv long term ecological research (LTER) Nature Park, in Israel. Ecological data were retrieved from previous research conducted at the nature park, and the valuation of landscape values was performed using the replacement cost method and a contingent valuation survey. The relationship between ES value and species richness was found to be negative. Of all management alternatives studied, only the planted conifer forest alternative was found to be inefficient; moving to other alternatives would enhance ES provision levels and species richness. This research demonstrates a simple path for providing land managers with an ecological data-based tool for comparing management alternatives in monetary terms.