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יואב האזורית במועצה אגרואקולוגי פרויקט של שנה .ביואב אגרואקולוגיה מסכם דוח סביבה תומכת חקלאות המועצה בשטח יואב האזורית והקמת קיים ידע שילוב : רב פורום-בר ליישום גורמי-קיימא
Abstract and Figures
המועצה האזורית יואב שוכנת בשפלת יהודה הדרומית ומשתרעת על שטח של כ 701,111- דונמים. 30%
מתוך שטח המועצה משמשים לחקלאות וכ- 72% מהשטח הינם יערות, ואדיות ושטחי בור אחרים.
שילוב זה בין שטחי חקלאות רבים בסמוך ובצמוד לשטחי בור רבים אשר מכילים בתוכם ערכיות
אקולוגית ומגוון ביולוגי גבוהים ביותר, מטילים על המועצה והחקלאים אחריות לשמירה ולהגנה על
המערכת הביולוגית. אחד ההיבטים של אחריות זו הינה תוכנית לניהול חקלאי של המרחב תוך הטמעה
ושימוש בכלים של חקלאות ידידותית לסביבה.
במהלך שנת 7102 התחלנו ביחד עם ראשת המועצה, ד"ר מטי צרפתי הרכבי, ועם חקלאים ותושבי
המועצה, בתהליך שמטרתו לבנות ארגז כלים אופרטיבי על בסיס הפעילות החקלאית בשטח וזאת
בכדי לעזור למועצה האזורית לקדם תהליכי ממשק חקלאי אקולוגי. בכדי לעמוד ביעד זה הקמנו ועדת
היגוי רחבה. מתוך ועדת היגוי זו בחרנו והקמנו ועדה מקצועית מצומצמת אשר פיתחה את
מטודולוגיות העבודה וקדמה את תהליך העבודה לאורך השנה כולה.
תהליך העבודה כלל שני שלבים מרכזים: א. אפיון של המערכת האקולוגית; ב. אפיון של המערכת
החקלאית. אפיון המערכת האקולוגית בוצע באמצעות ניתוח וסינתזה של מידע אקולוגי רב אשר
נאסף במהלך השנים במחקרים מדעיים שונים, בסקרי שדה, באמצעות פקחי רט"ג ועוד. אפיון
המערכת החקלאית בוצע באמצעות סיורים שנערכו בישובים השונים ובאמצעות שאלונים אשר הופנו
לרכזי הגד"ש, מנהלי מטעים ועובדים חקלאיים נוספים.
על בסיס המידע שהצטבר ניסחנו שורה של המלצות למועצה האזורית יואב בדרך להפיכתה למועצה
אזורית המעודדת חקלאות ידידותית לסביבה. המלצות אלו משתלבות עם גישות רחבות יותר, כלל ארציות, לחקלאות ידידותית לסביבה כפי שנוסחו ונכתבו על יד משרד החקלאות.
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Agroecology involves various approaches to solve actual challenges of agricultural production. Though agroecology initially dealt primarily with crop production and protection aspects, in recent decades new dimensions such as environmental, social, economic, ethical and development issues are becoming relevant. Today, the term 'agroecology' means either a scientific discipline, agricultural practice, or political or social movement. Here we study the different meanings of agroecology. For that we analyse the historical development of agroecology. We present examples from USA, Brazil, Germany, and France. We study and discuss the evolution of different meanings agroecology. The use of the term agroecology can be traced back to the 1930s. Until the 1960s agroecology referred only as a purely scientific discipline. Then, different branches of agroecology developed. Following environmental movements in the 1960s that went against industrial agriculture, agroecology evolved and fostered agroecological movements in the 1990s. Agroecology as an agricultural practice emerged in the 1980s, and was often intertwined with movements. Further, the scales and dimensions of agroecological investigations changed over the past 80 years from the plot and field scales to the farm and agroecosystem scales. Actually three approaches persist: ( 1) investigations at plot and field scales, ( 2) investigations at the agroecosystem and farm scales, and ( 3) investigations covering the whole food system. These different approaches of agroecological science can be explained by the history of nations. In France, agroecology was mainly understood as a farming practice and to certain extent as a movement, whereas the corresponding scientific discipline was agronomy. In Germany, agroecology has a long tradition as a scientific discipline. In the USA and in Brazil all three interpretations of agroecology occur, albeit with a predominance of agroecology as a science in the USA and a stronger emphasis on movement and agricultural practice in Brazil. These varied meanings of the term agroecology cause confusion among scientists and the public, and we recommend that those who publish using this term be explicit in their interpretation.
Processes that affect ecological community measurements, such as abundance, species richness or species diversity, form the framework of ecology. For years these processes were investigated by examining local factors (explanatory variables) that may affect the relationship between individuals or species on a local scale. Over the last two decades, due to the rise of advanced scientific theory and practice, new computational and statistical approaches have been developed, allowing ecologists to examine community structure and measurements using several scale-dependent variables and processes. Despite much research conducted in this field, reptiles as a biological group have been somewhat neglected compared to other groups (e.g. birds, insects, rockpools).
Over the years, various studies have been conducted on the structure of ecological communities within agricultural systems, using diverse approaches, including advanced methods of spatial ecology. However, contiguous farmland is rarely spread over a sharp climatic gradient, so the effect of such a gradient on community structure within an agricultural system is currently understudied. In addition, in cases where a climatic gradient exists, it is usually accompanied by changes in elevation, ground composition, and geology, and, as expected, in the agricultural activity itself.
The study area for this thesis, the Southern Judea Lowlands, is characterized by a very sharp climatic gradient over a short distance, with no significant change in elevation, soil, geology, human history or agricultural activities. This PhD thesis examines scale-dependent variables that affect the reptile community within natural patches in the fragmented agricultural system of the Southern Judea Lowlands.
The first chapter addresses the effect of different spatial scale variables on the reptile community located in natural patches within an agricultural matrix. Three 3.2×4 km land units were chosen, located from north to south – Galon, Lachish and Dvir. These land-units reflect the north-south climatic gradient that exists at the landscape scale. Patches of varying size, shape and spatial configuration were identified within the land-units. Within these patches, I marked 100×50 m equal-sized plots which were used for sampling reptiles. This sampling method allowed me to examine how a series of variables (e.g. plot heterogeneity, patch size and spatial configuration), which operate at different spatial scales and may be related to different ecological processes, affect the reptile community. By using an AICc-based (Akaike Information Criterion with correction for finite sample sizes) model selection approach, I examined which variables most affect community structure. The models that offered the best explanation for the three community measurements – abundance, species richness and species diversity – were all multiple scale models. However, all three community measures were strongly affected by local scale variables which suggested a strong influence of local hetrogeneity on reptile communities. Moreover, for all three community measures, both grazing and climatic gradients together were found to be an important variable, which indicates the significance of this combined environmental phenomenon.
The second chapter deals with one of the most common agricultural activities within my research area -- seasonal grazing of sheep (Ovis aries) and cattle (Bos primigenius). Grazing takes place mainly in the stubble after harvest, but herds also find natural patches located within the agricultural matrix. Previous studies have examined the effect of domestic animal grazing on reptile communities, but few of these have examined the integrated effects of grazing and climate, especially within a similar area. In Chapter 2, I examine the combined effect of grazing and climatic gradient on the reptile community of the Southern Judea Lowlands with an additional site to the south – Rahat. I list the proportion of species according to their biogeographical origin. The results indicate a decrease in the percentage and relative abundance of Mediterranean species and an increase in the percentage and abundance of desert species with decreasing precipitation. The effect of grazing itself also changed according to the location of the plot along the climatic gradient. Within the Galon land-unit, which belongs to the Mediterranean climate, grazing was found to increase plot heterogeneity and species richness. In contrast, in the southern area, near Dvir, a negative effect of grazing on plot heterogeneity and species richness was found. At Dvir, grazing was also found to affect community composition. Mediterranean-oriented species richness was negatively affected by grazing intensity. In contrast, arid-oriented species richness was positively related to grazing intensity at Dvir.
Apart from grazing, the study area is also characterized by the presence of vast wheat fields. In the third chapter of the work I address the effect of wheat fields on the reptile communities. I chose to focus on plots located in the center of wheat fields which were all concentrated in the northern land-unit Galon, in order to avoid in this analysis the impact of the climatic gradient. In addition, due to the paucity of observations of other species, this part of the study focused on the lizard Bridled Mabuya (Trachylepis vittata) only. Arthropod abundance found in the early spring within the wheat fields was significantly higher than in natural patches. In addition, I found a significant movement of reptiles from natural patches to the wheat fields, but very little in the opposite direction. The physical condition of the individuals who left the natural patches for the fields was significantly better than that of the individuals who remained in the natural patches. Finally, no individuals were found within the wheat fields after the harvest in contrast to the natural patches. These results indicate that wheat fields act as an ecological trap for T. vittata. This third chapter has been accepted for publication in the journal Biological Conservation.
In conclusion, the results of this work suggest that the reptile community within a fragmented agro-ecosystem is affected by many scale-dependent ecological processes. The results also suggest that the presence of a reptile community within an agricultural area is affected by the type of agricultural crop and other agricultural practices. My research highlights the need to consider various scale-dependent ecological variables, as well as the type of agricultural activity, when investigating ecological communities within an agricultural area.
Areas of environmental transition, where ecological communities coincide, are sometimes termed ecotones. These regions often correspond with sharp environ - mental gradients. Ecotones occur at multiple spatial scales, ranging from transi- tions between biomes to local small-scale transitions. In recent years ecotones have received increasing scientific attention after being neglected for years, as studies historically often focused on distinct communities. However, it is still de - batable whether these transitional regions are speciation and biodiversity hotspots that deserve special conservation interest or are actually areas that hold marginal populations that depend on other parts of the range for the maintenance of their biodiversity and therefore should not deserve primary investment. This paper discusses some of the recent advancements in our understanding of the role of ecotones in ecology, evolution, and conservation.
Environmental conditions outside the periphery of a species' distribution prevent population persistence, hence peripheral populations live under conditions different from those of core populations. Peripheral areas are characterized by variable and unstable conditions, relative to core areas. Peripheral populations are expected to be genetically more variable, since the variable conditions induce fluctuating selection, which maintains high genetic diversity. Alternatively, due to marginal ecological conditions at the periphery, populations there are small and isolated; the within-population diversity is low, but the between-population genetic diversity is high due to genetic drift. It is also likely that peripheral populations evolve resistance to extreme conditions. Thus, peripheral populations rather than core ones may be resistant to environmental extremes and changes, such as global climate change induced by the anthropogenically emitted “greenhouse gases”. They should be treated as a biogen...
Species-area relationships (SPARs) dictate a sea change in the strategies of biodiversity conservation. SPARs exist at three ecological scales: Sample-area SPARs (a larger area within a biogeographical province will tend to include more habitat types, and thus more species, than a smaller one), Archipelagic SPARs (the islands of an archipelago show SPARs that combine the habitat-sampling process with the problem of dispersal to an island), and Interprovincial SPARs (other things being equal, the speciation rates of larger biogeographical provinces are higher and their extinction rates are lower, leading to diversities in proportion to provincial area). SPARs are the products of steady-state dynamics in diversity, and such dynamics appears to have characterized the earth for most of the last 500 million years. As people reduce the area available to wild species, they impose a linear reduction of the earth's species diversity that will follow the largest of these scales, i.e. each 1% reduction of natural area will cost about 1% of steady-state diversity. Reserving small tracts of wild habitat can only delay these reductions. But we can stop most of them by redesigning anthropogenic habitats so that their use is compatible with use by a broad array of other species. That is reconciliation ecology. Many pilot projects, whether intentionally or inadvertently espousing reconciliation ecology, are demonstrating that it can be done.
Recent studies suggest that patterns of genetic diversity significantly influence the viability and persistence of local populations. Revealing and mapping spatial patterns of genetic diversity within species' ranges may be vital when defining criteria and prioritizing areas for conservation. Chukar Partridges (Alectoris chukar) in Israel occur along a steep ecogeographical gradient extending from mesic Mediterranean zones in the north to steppe and desert regions in the south. To rest the hypothesis that the most genetically diverse populations within a species' range occur within the ecotone, an area of transition between ecosystems where a sharp environmental gradient exists, we examined the allozyme diversity of chukars collected at five locations within the species' continuous range in each of 2 years. Based on 32 allozyme loci, the genetic diversity of chukars increased significantly, along a gradient from population in Mediterranean regions to those at the ecotone in the northern Negev desert, despite close geographical proximity among populations Genetic diversity As estimated by percent polymorphic loci, observed and expected heterozygosity, and mean number of alleles was not homogeneous among sampling localities: single and multilocus Hardy-Weinberg and linkage disequilibria increased along the gradient toward the ecotone. Populations exhibited some isolation by distance effects in the face of substantial gene flow. We therefore recommend that higher conservation priority be assigned to the Mediterranean-Negev ecotone area. For Chukar Partridges, it supports the highest overall genetic diversity across ecological gradients. Rapid urbanization of Israeli landscapes, and management of chukars in Israel within a metapopulation context is an urgent requirement.
Agricultural activities such as tillage, drainage, intercropping, rotation, grazing and extensive usage of pesticides and fertilizers have significant implications for wild species of flora and fauna. Species capable of adapting to the agricultural landscape may be limited directly by the disturbance regimes of grazing, planting and harvesting, and indirectly by the abundance of plant and insect foods available. Some management techniques, such as drainage, create such fundamental habitat changes that there are significant shifts in species composition. This paper considers the relative merits of conventional tillage versus reduced, or no-till farming, and reviews the benefits of rest-rotation grazing, crop rotation and intercropping in terms of maintaining wild species populations.
As humanity presses down inexorably on the natural world, people debate the extent to which we can save the Earth’s millions of different species without sacrificing human economic welfare. But is this argument wise? Must the human and natural worlds be adversaries? In this book, ecologist Michael Rosenzweig finds that ecological science actually rejects such polarization. Instead it suggests that, to be successful, conservation must discover how we can blend a rich natural world into the world of economic activity. This revolutionary, common ground between development and conservation is called reconciliation ecology: creating and maintaining species-friendly habitats in the very places where people live, work, or play. The book offers many inspiring examples of the good results already achieved. The Nature Conservancy, for instance, has a cooperative agreement with the Department of Defense, with more than 200 conservation projects taking place on more than 170 bases in 41 states. In places such as Elgin Air Force Base, the human uses-testing munitions, profitable timbering and recreation--continue, but populations of several threatened species on the base, such as the long-leaf pine and the red-cockaded woodpecker, have been greatly improved. The Safe Harbor strategy of the Fish & Wildlife Service encourages private landowners to improve their property for endangered species, thus overcoming the unintended negative aspects of the Endangered Species Act. And Golden Gate Park, which began as a system of sand dunes, has become, through human effort, a world of ponds and shrubs, waterfowl and trees. Rosenzweig shows that reconciliation ecology is the missing tool of conservation, the practical, scientifically based approach that, when added to the rest, will solve the problem of preserving Earth’s species.
Landscape modification and habitat fragmentation are key drivers of global species loss. Their effects may be understood by focusing on: (1) individual species and the processes threatening them, and (2) human-perceived landscape patterns and their correlation with species and assemblages. Individual species may decline as a result of interacting exogenous and endogenous threats, including habitat loss, habitat degradation, habitat isolation, changes in the biology, behaviour, and interactions of species, as well as additional, stochastic threats. Human-perceived landscape patterns that are frequently correlated with species assemblages include the amount and structure of native vegetation, the prevalence of anthropogenic edges, the degree of landscape connectivity, and the structure and heterogeneity of modified areas. Extinction cascades are particularly likely to occur in landscapes with low native vegetation cover, low landscape connectivity, degraded native vegetation and intensive land use in modified areas, especially if keystone species or entire functional groups of species are lost. This review (1) demonstrates that species-oriented and pattern-oriented approaches to understanding the ecology of modified landscapes are highly complementary, (2) clarifies the links between a wide range of interconnected themes, and (3) provides clear and consistent terminology. Tangible research and management priorities are outlined that are likely to benefit the conservation of native species in modified landscapes around the world.