Of the species only at controls, 80% were represented by a single individual. The species only at hedgerows tended to have more specialized nesting requirements , whereas those only at controls were primarily generalists . Also, although the majority of the species were found at both hedgerows and unrestored controls , species ranging from relatively rare to common were infrequent at controls and more abundant in hedgerows . Interestingly, the three species observed over 100 times, Lasioglossum incompletum, Halictus tripartitus and Halictus ligatus, all small-bodied floral and nesting resource generalists, were at similar abundances in hedgerows and unrestored controls, if not slightly more abundant in controls .Although hedgerows may help counter homogenization of pollinator communities in simplified agricultural landscapes, comparing the spatial heterogeneity they support to that which is observed in natural communities is important in assessing their overall conservation value. In remnant chaparral/oak woodland communities in the same ecoregion and adjacent to our study landscapes , an average of 30% of species were not shared across sites located within 3.5–50 km of each other. The Central Valley, which was once described as ‘one vast, level, even flower-bed’ , has been extensively converted to agriculture, likely limiting the species pool due to local extinctions. Even so, at hedgerows an average of 15 km apart, we found between 36% and 67% of species were not shared between sites, depending on the year. Both the spatial scale and biota of our study and that of are comparable, suggesting that hedgerows are, in fact,grow strawberry in containers restoring spatial heterogeneity to approximately the same range as might occur in adjacent natural systems. In addition, in the disparate landscape of the southwestern United States, a diversity hot spot for bees , 61% of species were not shared across sites within 1–5 km of each other .

Although the species pool is richer in the southwest, the amount of species turnover at hedgerows is not unlike what is observed in that highly heterogeneous region . Thus, across many aspects of biodiversity, hedgerows might provide a valuable measure for conserving biodiversity . Only mature hedgerows in this study supported higher trait and b-diversity when compared to non-restored farm edges. Thus, the processes that lead to a buildup of spatial turnover in pollinator communities are slow and may take considerable time before observably affecting pollinator communities. However, we have recently shown that hedgerow restoration leads to increased rates of colonization and persistence of pollinators in maturing hedgerows and that this effect becomes stronger over time . Further, we found that maturing hedgerows differentially support more specialized species over time . These two temporal studies on the early phases of hedgerow maturation show that hedgerows begin to impact pollinator communities much earlier than 10 years. Combined, these findings suggest a possible mechanism whereby restoration might lead to increases in species turnover; as a hedgerow matures, species with a wider variety of life-history traits are better able to colonize and persist there, thus leading to the accumulation of differences in community composition between sites over time. This then leads to greater spatial heterogeneity in pollinator communities at hedgerows. Conversely, in unrestored areas, the rate of colonization and persistence is lower, particularly for species with more specialized habitat requirements, thereby creating an ecological filter that limits the total diversity and, thus, turnover that is possible. This above-described process can be, in part, deterministic; restored and non-restored farm edges differ fundamentally in which pollinator species are able to colonize and/or persist in them . Thus, pollinators respond to the differences in the plant communities between hedgerows and controls, and the pollinator community at mature hedgerows tracks floral hosts. Interestingly, however, the pollinator communities at hedgerows that were closer to one another were not necessarily more similar than sites that were further apart.

In addition, hedgerows maintain b-diversity in the landscape by supporting unique combinations of species, and we did not find evidence that communities at hedgerows were nested subsets of one another . Because hedgerows are planted, the floral communities the pollinators are tracking will not necessarily be spatially structured like natural communities. In addition, bees are known to be highly spatially and temporally variable and thus, stochastic processes that do not result in spatial structuring are likely operating as communities assemble. In contrast to within hedgerows, the dissimilarity of pollinators at unrestored controls responded positively to geographic distance. Because the conditions at controls are relatively uniform across space, this suggests a role for dispersal limitation in determining pollinator community composition at unrestored controls . In addition, the number of shared species between hedgerows and controls was also positively related to distance , suggesting the communities at controls may be influenced by landscape context such as the presence of nearby hedgerows.Here we focus on the effects of hedgerows on b-diversity, but there are likely other contributions to spatial heterogeneity in our landscape. There are a number of crops that provide floral resources to pollinators in our area, including mass-flowering sunflower, melons, and almonds . Different crops attract different pollinators and thus may affect the spatial heterogeneity of communities. In addition, some crops might also pull resident species from the hedgerows , while others may attract species that may subsequently colonize hedgerows . Differences in adjacent crops between hedgerows and unrestored controls thus may add noise to the underlying signal of b-diversity. However, because hedgerows and controls are matched for crop type, while there may be a contribution of crop type on b-diversity, it should be a random one affecting hedgerows and controls simultaneously. To achieve sustainable food production while protecting biodiversity, we need to grow food in a manner that protects, utilizes, and regenerates ecosystem services, rather than replacing them .

Diversification practices such as installing hedgerows, when replicated across a landscape, may provide a promising mechanism for conserving and restoring ecosystem services and biodiversity in working landscapes while potentially improving pollination and crop yields .Increasing population and consumption have raised concerns about the capability of agriculture in the provision of future food security. Te overarching effects of climate change pose further threats to the sustainability of agricultural systems. Recent estimates suggested that global agricultural production should increase by 70% to meet the food demands of a world populated with ca. 9.1 billion people in 2050. Food security is particularly concerning in developing countries, as production should double to provide sufficient food for their rapidly growing populations. Whether there are enough land and water resources to realize the production growth needed in the future has been the subject of several global-scale assessments. Te increase in crop production can be achieved through extensifcation and/or intensifcation. At the global scale, almost 90% of the gain in production is expected to be derived from improvement in the yield,hydroponic nft channel but in developing countries, land expansion would remain a significant contributor to the production growth. Land suitability evaluations, yield gap analysis, and dynamic crop models have suggested that the sustainable intensification alone or in conjugation with land expansion could fulfil the society’s growing food needs in the future. Although the world as a whole is posited to produce enough food for the projected future population, this envisioned food security holds little promise for individual countries as there exist immense disparities between regions and countries in the availability of land and water resources, and the socio-economic development. Global Agro-Ecological Zone analysis suggests that there are vast acreages of suitable but unused land in the world that can potentially be exploited for crop production; however, these lands are distributed very unevenly across the globe with some regions, such as the Middle East and North Africa , deemed to have very little or no land for expansion. Likewise, globally available fresh water resources exceed current agricultural needs but due to their patchy distribution, an increasing number of countries, particularly in the MENA region, are experiencing severe water scarcity.

Owing to these regional differences, location-specific analyses are necessary to examine if the available land and water resources in each country will suffice the future food requirements of its nation, particularly if the country is still experiencing significant population growth.As a preeminent agricultural country in the MENA region, Iran has long been pursuing an ambitious plan to achieve food self- sufficiency. Iran’s self- sufficiency program for wheat started in 1990, but the low rate of pro-duction increase has never sustainably alleviated the need for grain imports. Currently, Iran’s agriculture supplies about 90% of the domestic food demands but at the cost of consuming 92% of the avail-able freshwater. In rough terms, the net value of agricultural import is equal to 14% of Iran’s cur-rent oil export gross revenue. Located in a dry climatic zone, Iran is currently experiencing unprecedented water shortage problems which adversely, and in some cases irreversibly, affect the country’s economy, ecosystem functions, and lives of many people. Te mean annual precipitation is below 250 mm in about 70% of the country and only 3% of Iran, i.e. 4.7 million ha, receives above 500 mm yr−1 precipitation . The geographical distribution of Iran’s croplands shows that the majority of Iran’s cropping activities take place in the west, northwest, and northern parts of the country where annual precipitation exceeds 250 mm . However, irrigated cropping is practiced in regions with precipitations as low as 200 mm year−1, or even below 100 mm year−1. To support agriculture, irrigated farming has been implemented unbridled, which has devastated the water scarcity problem.The increase in agricultural production has never been able to keep pace with raising demands propelled by a drastic population growth over the past few decades, leading to a negative net international trade of Iran in the agriculture sector with a declining trend in the near past . Although justified on geopolitical merits, Iran’s self-sufficiency agenda has remained an issue of controversy for both agro-ecological and economic reasons. Natural potentials and constraints for crop production need to be assessed to ensure both suitability and productivity of agricultural systems. However, the extents to which the land and water resources of Iran can meet the nation’s future food demand and simultaneously maintain environmental integrity is not well understood. With recent advancement in GIS technology and availability of geospatial soil and climate data, land suitability analysis now can be conducted to gain insight into the capability of land for agricultural activities at both regional and global scales. Land evaluation in Iran has been conducted only at local, small scales and based on the specific requirements of a few number of crops such wheat, rice and faba bean. However, there is no large scale, country-wide analysis quantifying the suitability of Iran’s land for agricultural use. Herein, we systematically evaluated the capacity of Iran’s land for agriculture based on the soil properties, topography, and climate conditions that are widely known for their relevance with agricultural suitability. Our main objectives were to: quantify and map the suitability of Iran’s land resources for cropping, and examine if further increase in production can be achieved through agriculture expansion and/or the redistribution of croplands without expansion. The analyses were carried out using a large number of geospatial datasets at very high spatial resolutions of 850m and 28m . Our results will be useful for estimating Iran’s future food production capacity and hence have profound implications for the country’s food self-sufficiency program and international agricultural trade. Although the focus of this study is Iran, our approach is transferrable to other countries, especially to those in the MENA region that are facing similar As a preeminent agricultural country in the MENA region, Iran has long been pursuing an ambitious plan to achieve food self- sufficiency. Iran’s self- sufficiency program for wheat started in 1990, but the low rate of production increase has never sustainably alleviated the need for grain imports. Currently, Iran’s agriculture supplies about 90% of the domestic food demands but at the cost of consuming 92% of the available freshwater. In rough terms, the net value of agricultural import is equal to 14% of Iran’s current oil export gross revenue. Located in a dry climatic zone, Iran is currently experiencing unprecedented water shortage problems which adversely, and in some cases irreversibly, affect the country’s economy, ecosystem functions, and lives of many people.