Evaluation of remote sensing for the detection of landfill gas and leachate in an urban environment

The technique of remote sensing provides a unique view of the earth's surface and considerable areas can be surveyed in a short amount of time. The aim of this project was to evaluate whether remote sensing, particularly using the Airborne Thematic Mapper (ATM) with its wide spectral range, was capable of monitoring landfill sites within an urban environment with the aid of image processing and Geographical Information Systems (GIS) methods. The regions under study were in the West Midlands conurbation and consisted of a large area in what is locally known as the Black Country containing heavy industry intermingled with residential areas, and a large single active landfill in north Birmingham. When waste is collected in large volumes it decays and gives off pollutants. These pollutants, landfill gas and leachate (a liquid effluent), are known to be injurious to vegetation and can cause stress and death. Vegetation under stress can exhibit a physiological change, detectable by the remote sensing systems used. The chemical and biological reactions that create the pollutants are exothermic and the gas and leachate, if they leave the waste, can be warmer than their surroundings. Thermal imagery from the ATM (daylight and dawn) and thermal video were obtained and used to find thermal anomalies on the area under study. The results showed that vegetation stress is not a reliable indicator of landfill gas migration, as sites within an urban environment have a cover too complex for the effects to be identified. Gas emissions from two sites were successfully detected by all the thermal imagery with the thermal ATM being the best. Although the results were somewhat disappointing, recent technical advancements in the remote sensing systems used in this project would allow geo-registration of ATM imagery taken on different occasions and the elimination of the effects of solar insolation.

The investigation of vegetation change using remote sensing to detect and monitor migration of landfill gas

Decomposition of domestic wastes in an anaerobic environment results in the production of landfill gas. Public concern about landfill disposal and particularly the production of landfill gas has been heightened over the past decade. This has been due in large to the increased quantities of gas being generated as a result of modern disposal techniques, and also to their increasing effect on modern urban developments. In order to avert diasters, effective means of preventing gas migration are required. This, in turn requires accurate detection and monitoring of gas in the subsurface. Point sampling techniques have many drawbacks, and accurate measurement of gas is difficult. Some of the disadvantages of these techniques could be overcome by assessing the impact of gas on biological systems. This research explores the effects of landfill gas on plants, and hence on the spectral response of vegetation canopies. Examination of the landfill gas/vegetation relationship is covered, both by review of the literature and statistical analysis of field data. The work showed that, although vegetation health was related to landfill gas, it was not possible to define a simple correlation. In the landfill environment, contribution from other variables, such as soil characteristics, frequently confused the relationship. Two sites are investigated in detail, the sites contrasting in terms of the data available, site conditions, and the degree of damage to vegetation. Gas migration at the Panshanger site was dominantly upwards, affecting crops being grown on the landfill cap. The injury was expressed as an overall decline in plant health. Discriminant analysis was used to account for the variations in plant health, and hence the differences in spectral response of the crop canopy, using a combination of soil and gas variables. Damage to both woodland and crops at the Ware site was severe, and could be easily related to the presence of gas. Air photographs, aerial video, and airborne thematic mapper data were used to identify damage to vegetation, and relate this to soil type. The utility of different sensors for this type of application is assessed, and possible improvements that could lead to more widespread use are identified. The situations in which remote sensing data could be combined with ground survey are identified. In addition, a possible methodology for integrating the two approaches is suggested.

Policy issues in rural areas:an examination with special reference to Cumbria

This thesis develops the requirements of the Cumbria Division of the MAFF to have detailed information on a number of rural topics of particular concern to the area's socia-economic advisory service. Information was generated upon the effects of road developments upon agriculture; the possibility of economic and employment growth through tourism, industry, forestry and agriculture; and upon their relationship with conservation and development control issues generally. A working conference was organised (The Whitbarrow Exercise) to review in specific terms a number of the above problems, in which representatives of the major groups active in rural policy formulation and implementation participated. The study was extended to consider these policy issues on a more prosperous agricultural estate; and in the county of Cumbria as a whole. An examination of the development and likely future impact of agricultural policy upon rural policy generally was also undertaken. All the research was set in the context of an extensive literature review. The results indicate that while state intervention to relieve those problems collectively known as rural deprivation still has an important place in modern rural policy, the scope for such intervention to be successful is limited. Opportunities for employment and wealth creation through tourism, forestry, industry and agriculture are limited for social and economic reasons; developments in these sectors can have adverse effects upon the environment; can compound existing problems; and are often resisted by local people. The lack of success of such ventures indicates continued structural change within rural communities, with some adverse effects for the less privileged members. Recognising this it is argued that fural policy seeks to adapt to, rather than attempt to fundamentally alter inevitable change, recognising that in the long term social and structural problems will resolve themselves. It is further argued that a reduction in state support for agriculture appears inevitable, and this can bring considerable conservation benefits, even in upland areas where positive links between agriculture and conservation have been found by some commentators. It is also argued that for social and economic reasons, and because of the declining importance of agricultural land, a vigorous landscape and ecological conservation policy is pursued by planning authorities and is reasonable. With regard to road developments on agricultural land, the research has shawn that although it is the norm far the agricultural community to experience severe difficulty during developments, these can be overcame by increasing the resources of professional expertise available to affected farmers. This indicates a possible important increased role for the MAFF in the development process.

A framework for automatic feature extraction from airborne light detection and ranging data

Recent advances in airborne Light Detection and Ranging (LIDAR) technology allow rapid and inexpensive measurements of topography over large areas. Airborne LIDAR systems usually return a 3-dimensional cloud of point measurements from reflective objects scanned by the laser beneath the flight path. This technology is becoming a primary method for extracting information of different kinds of geometrical objects, such as high-resolution digital terrain models (DTMs), buildings and trees, etc. In the past decade, LIDAR gets more and more interest from researchers in the field of remote sensing and GIS. Compared to the traditional data sources, such as aerial photography and satellite images, LIDAR measurements are not influenced by sun shadow and relief displacement. However, voluminous data pose a new challenge for automated extraction the geometrical information from LIDAR measurements because many raster image processing techniques cannot be directly applied to irregularly spaced LIDAR points. ^ In this dissertation, a framework is proposed to filter out information about different kinds of geometrical objects, such as terrain and buildings from LIDAR automatically. They are essential to numerous applications such as flood modeling, landslide prediction and hurricane animation. The framework consists of several intuitive algorithms. Firstly, a progressive morphological filter was developed to detect non-ground LIDAR measurements. By gradually increasing the window size and elevation difference threshold of the filter, the measurements of vehicles, vegetation, and buildings are removed, while ground data are preserved. Then, building measurements are identified from no-ground measurements using a region growing algorithm based on the plane-fitting technique. Raw footprints for segmented building measurements are derived by connecting boundary points and are further simplified and adjusted by several proposed operations to remove noise, which is caused by irregularly spaced LIDAR measurements. To reconstruct 3D building models, the raw 2D topology of each building is first extracted and then further adjusted. Since the adjusting operations for simple building models do not work well on 2D topology, 2D snake algorithm is proposed to adjust 2D topology. The 2D snake algorithm consists of newly defined energy functions for topology adjusting and a linear algorithm to find the minimal energy value of 2D snake problems. Data sets from urbanized areas including large institutional, commercial, and small residential buildings were employed to test the proposed framework. The results demonstrated that the proposed framework achieves a very good performance. ^

Historic primary producer communities linked to water quality and hydrologic changes in the northern Everglades

The northern Everglades Water Conservation Areas have experienced recent ecological shifts in primary producer community structure involving marl periphyton mats and dense Typha-dominated macrophyte stands. Multiple investigations have identified phosphorus (P) as a driver of primary producer community structure, but effects of water impoundment beginning in the 1950s and changes in water hardness [e.g., (CaCO3)] have also been identified as a concern. In an effort to understand pre-1950, primary producer community structure and identify community shifts since 1950, we measured pigment proxies on three sediment cores collected in Water Conservation Area-2A (WCA-2A) along a phosphorus enrichment gradient. Photosynthetic pigments, sediment total phosphorus content (TP), organic matter, total organic carbon and nitrogen were used to infer historic primary producer communities and changes in water quality and hydrology regulating those communities. Excess 210Pb was used to establish historic dates for the sediment cores. Results indicate the northern area of WCA-2A increased marl deposition and increased algal abundance ca. 1920. This increase in (presumably) calcareous periphyton before intensive agriculture and impoundment suggest canal-derived calcium inputs and to some extent early drainage effects played a role in initiating this community shift. The northern area community then shifted to Typha dominance around 1965. The areas to the south in WCA-2A experienced increased marl deposition and algal abundance around or just prior to 1950s impoundment, the precise timing limited by core age resolution. Continued increases in algal abundance were evident after 1950, coinciding with impoundment and deepening of canals draining into WCA-2A, both likely increasing water mineral and nutrient concentrations. The intermediate site developed a Typha-dominated community ca. 1995 while the southern-most core site WCA-2A has yet to develop Typha dominance. Numerous studies link sediment TP >650 mg P/kg to marsh habitat degradation into Typha-dominance. The northern and intermediate cores where Typha is currently support this previous research by showing a distinct shift in the sediment record to Typha dominance corresponding to sediment TP between 600 and 700 mg P/kg. These temporal and spatial differences are consistent with modern evidence showing water-column gradients in mineral inputs (including Ca, carbonates, and phosphorus) altering primary producer community structure in WCA-2A, but also suggest hydroperiod has an effect on the mechanisms regulating periphyton development and Typha dominance.

Evidence of Recent Phosphorus Enrichment in Surface Soils of Taylor Slough and Northeast Everglades National Park

Everglades National Park (ENP) is the last hydrologic unit in the series of impounded marsh units that make up the present-day Everglades. The ENP receives water from upstream Water Conservation Areas via canals and water control structures that are highly regulated for flood control, water supply, wildlife management, concerns about poor water quality and the potential for downstream ecosystem degradation. Recent surveys of surface soils in ENP, designed for random sampling for spatial analysis of soil nutrients, did not sample proximate to inflow structures and thus did not detect increased soil phosphorus associated with these water conveyances. This study specifically addressed these areas in a focused sampling effort at three key inflow points in northeast ENP which revealed elevated soil TP proximate to inflows. Two transects extending down Shark River Slough and one down Taylor Slough (a natural watershed of particular ecological value) were found to have soil TP levels in excess of 500 mg kg−1—a threshold above which P enrichment is indicated. These findings suggest the negative impact of elevated water (P) from surface flows and support the assertion that significant soil TP enrichment is occurring in Taylor Slough and other areas of northeastern ENP.

Tree Islands in Everglades Landscapes: Current Status, Historical Changes, and Hydrologic Impacts on Population Dynamics and Moisture Relations, First Annual Report

In 2005 we initiated a project designed to better understand tree island structure and function in the Everglades and the wetlands bordering it. Focus was on the raised portions at the upstream end of the islands, where tropical hardwood species adapted to well-drained conditions usually are the most prominent component of the vegetation. The study design is hierarchical, with four levels; in general, a large number of sites is to be surveyed once for a limited set of parameters, and increasingly small sets of islands are to be sampled more intensively, more frequently, and for more aspects of ecosystem function. During the first year of the 3-year study, we completed surveys of 41 Level 1 (i.e., the least intensive level) islands, and established permanent plots in two and three islands of Levels 2 and 4 intensity, respectively. Tree species richness and structural complexity was highest in Shark Slough “hammocks”, while islands in Northeast Shark Slough and Water Conservation Area 3B, which receive heavy human use, were simpler, more park-like communities. Initial monitoring of soil moisture in Level 4 hammocks indicated considerable local variation, presumably associated with antecedent rainfall and current water levels in the adjacent marsh. Tree islands throughout the study area were impacted significantly by Hurricanes Katrina and Wilma in 2005, but appear to be recovering rapidly. As the project continues to include more islands and repeated measurements, we expect to develop a better grasp of tree island dynamics across the Everglades ecosystem, especially with respect to moisture relations and water levels in the adjacent marsh. The detailed progress report which follows is also available online at http://www.fiu.edu/~serp1/projects/treeislands/tree_islands_2005_annual_report.pd

Quantitative Comparison of Plant Community Hydrology Using Large-Extent, Long-Term Data

Large-extent vegetation datasets that co-occur with long-term hydrology data provide new ways to develop biologically meaningful hydrologic variables and to determine plant community responses to hydrology. We analyzed the suitability of different hydrological variables to predict vegetation in two water conservation areas (WCAs) in the Florida Everglades, USA, and developed metrics to define realized hydrologic optima and tolerances. Using vegetation data spatially co-located with long-term hydrological records, we evaluated seven variables describing water depth, hydroperiod length, and number of wet/dry events; each variable was tested for 2-, 4- and 10-year intervals for Julian annual averages and environmentally-defined hydrologic intervals. Maximum length and maximum water depth during the wet period calculated for environmentally-defined hydrologic intervals over a 4-year period were the best predictors of vegetation type. Proportional abundance of vegetation types along hydrological gradients indicated that communities had different realized optima and tolerances across WCAs. Although in both WCAs, the trees/shrubs class was on the drier/shallower end of hydrological gradients, while slough communities occupied the wetter/deeper end, the distribution ofCladium, Typha, wet prairie and Salix communities, which were intermediate for most hydrological variables, varied in proportional abundance along hydrologic gradients between WCAs, indicating that realized optima and tolerances are context-dependent.

Capparaceae: flora do Rio Grande do Norte e biogeografia no semiárido brasileiro

Capparaceae comprises 25 genera and 480 species, of which 110 are included in 18 genera in Neotropics. Its distribution is pantropical with high frequency in seasonally dry environments. Its representatives are woody, shrubs and rarely wines, with simple leave or compound 3-foliolate, shorts and deciduous floral bracts, tetramerous and nocturnal flowers with exserts and numerous stamens, ovary supero on a gynophore and fleshy fruits, dehiscents or indehiscentes. For Brazil, 12 genera and 28 species are recorded and 12 of that are endemic to the country, occurring preferentially in vegetation of savanna estépica s.str., seasonal semideciduos forest and restinga. This work shows two chapters. In the first chapter, the distributions patterns of the species occurring in the brazilian semi-arid region and their distribution intra Caatinga are discussed. The distribution patterns were determined from a review of the distribution of species in herbaria collections and supplemented with data obtained from specific bibliography about the family. A map containing 1 × 1 grid cells was used to evaluate the richness, collection efforts and floristic similarity of the species intra Caatinga. Six genera and eight species were registered in Caatinga. Four species are endemic to Brazil, with only one endemic to Caatinga, and the other four are widespread in Neotropics. Four distribution patterns were observed: restricted to the NE, broad and continuous in Brazil, disjunct and neotropical. All the species were recorded in Bahia, state with the highest species richness per grid cell and also remarkable sampling efforts species of the family. The state of Piauí presents priority areas for further collection of Capparaceae, due to low family representation in the state. The floristic similarity analysis intra Caatinga was low, 22 %, probably due to a few species of the family in the region and the wide distribution of the same. The second chapter presents the Capparaceae of flora to Rio Grande do Norte (RN), since the state has a little-known flora, with specific studies. Through collections in the state and herbaria review, five genera and six species of Capparaceae were recorded in RN: Capparidastrum (1 spp.); Crateva (1 spp.); Cynophalla (2 spp.); Mesocapparis (1 spp.) and Neocalyptrocalyx (1 spp.). Capparidastrum frondosum and Mesocapparis lineata are new records for the state. An identification key, descriptions and images, comments on the biology of the species and protected areas where they occur are showed.

Longitudinal Clinical Evaluation of Undercut Areas and Rest Seats of Abutment Teeth in Removable Partial Denture Treatment

PURPOSE: Adequate preparation of abutment teeth for removable partial denture (RPD) rest seats allows appropriate masticatory force transmission, retention, and stability of supporting structures. It follows that careful preparation will be important for the longevity of the rehabilitation. The present study aimed to clinically evaluate rest seats and undercut areas of abutment teeth in RPD wearers after 2 years of use. MATERIALS AND METHODS: A total of 193 occlusal, incisal, and cingulum rest seats were evaluated in terms of shape, rest adaptation, wear, caries, fractures, and surface type (enamel, composite resin, or amalgam). Two hundred and fourteen undercut areas were evaluated in terms of surface type (enamel or restoration) and integrity. This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, resolution 196/1996, protocol number 11/05. RESULTS: Intact preparations accounted for 92.2% of the total. Application of the Pearson test (p= 0.289) found no statistically significant differences among the materials on which the rest seats were prepared. For the undercut areas, 20.7% of those obtained on restorative material were nonintact. In addition, Fisher's exact test showed a statistically significant difference (p= 0.001) in surface type; enamel surfaces were shown to be 14 times more stable than restored surfaces. CONCLUSIONS: The results of this study suggest that rest seats are stable, regardless of the material on which they are prepared. Retentive areas were shown to be more stable when they were located in enamel.

Longitudinal Clinical Evaluation of Undercut Areas and Rest Seats of Abutment Teeth in Removable Partial Denture Treatment

PURPOSE: Adequate preparation of abutment teeth for removable partial denture (RPD) rest seats allows appropriate masticatory force transmission, retention, and stability of supporting structures. It follows that careful preparation will be important for the longevity of the rehabilitation. The present study aimed to clinically evaluate rest seats and undercut areas of abutment teeth in RPD wearers after 2 years of use. MATERIALS AND METHODS: A total of 193 occlusal, incisal, and cingulum rest seats were evaluated in terms of shape, rest adaptation, wear, caries, fractures, and surface type (enamel, composite resin, or amalgam). Two hundred and fourteen undercut areas were evaluated in terms of surface type (enamel or restoration) and integrity. This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, resolution 196/1996, protocol number 11/05. RESULTS: Intact preparations accounted for 92.2% of the total. Application of the Pearson test (p= 0.289) found no statistically significant differences among the materials on which the rest seats were prepared. For the undercut areas, 20.7% of those obtained on restorative material were nonintact. In addition, Fisher's exact test showed a statistically significant difference (p= 0.001) in surface type; enamel surfaces were shown to be 14 times more stable than restored surfaces. CONCLUSIONS: The results of this study suggest that rest seats are stable, regardless of the material on which they are prepared. Retentive areas were shown to be more stable when they were located in enamel.

Meiofaunal abundance, biomass, taxon richness and indices of nematode diversity of samples from the Santa Maria di Leuca Bank (southern Adriatic margin)

Deep-water coral ecosystems are hot spots of biodiversity and provide habitats and refuges for several deep-sea species. However, their role in shaping the biodiversity of the surrounding open slopes is still poorly known. We investigated how meiofaunal biodiversity varies with and is related to the occurrence of deep-water living scleractinian corals and coral rubble in two deep-sea areas (the Rockall Bank, northeastern Atlantic) and the Santa Maria di Leuca (central Mediterranean). In both areas, replicated sampling on alive and dead coral areas and from the adjacent slope sediments without corals (at the same and increasing depths) allowed us to demonstrate that sediments surrounding the living corals and coral rubble were characterised by higher meiofaunal biodiversity (as number of higher taxa, and nematode species richness) than the slope sediments. Despite the soft sediments surrounding the living coral having a higher nutritional value than those not associated with corals, with the opposite seen for coral rubble, the presence of both alive and dead corals had a significant effect on nematode assemblages. Our data suggest that, due particularly to the effects on habitat heterogeneity/complexity, both living coral and coral rubble promoted higher biodiversity levels than in surrounding slope sediments. We conclude that the protection of deep-water corals can be crucial to preserve the biodiversity of surrounding open slopes, and that the protection of dead corals, a so-far almost neglected habitat in terms of biological conservation, can further contribute to the maintenance of a high deep-sea biodiversity along continental margins.

Sea lice (Lepeophtheirus salmonis) and anchor worms (Lernaea cyprinacea) found on sea trout (Salmo trutta) in the River Minho catchment, an important area for conservation in NW Spain

Acknowledgements The authors would like to thank M. N. Cueto and J. M. Antonio (ECOBIOMAR) for molecular analysis and technical support. K. MacKenzie (University of Aberdeen) and A. Roura (ECOBIOMAR) assisted with the taxonomic identification of parasites. We are also grateful to P. Caballero (Service Nature Conservation of the Xunta de Galicia) for fish sampling support.

Using GIS and Remote Sensing Technologies to Identify Environmental Variables of Malaria Vector Breeding Sites in Western Kenya

This study used Landsat 8 satellite imagery to identify environmental variables of households with malaria vector breeding sites in a malaria endemic rural district in Western Kenya. Understanding the influence of environmental variables on the distribution of malaria has been critical in the strengthening of malaria control programs. Using remote sensing and GIS technologies, this study performed a land classification, NDVI, Tasseled Cap Wetness Index, and derived land surface temperature values of the study area and examined the significance of each variable in predicting the probability of a household with a mosquito breeding site with and without larvae. The findings of this study revealed that households with any potential breeding sites were characterized by higher moisture, higher vegetation density (NDVI) and in urban areas or roads. The results of this study also confirmed that land surface temperature was significant in explaining the presence of active mosquito breeding sites (P< 0.000). The present study showed that freely available Landsat 8 imagery has limited use in deriving environmental characteristics of malaria vector habitats at the scale of the Bungoma East District in Western Kenya.

Analyzing Gene Centres with the Help of the Checklist Method – the Case of Syria

The present survey of species diversity of cultivated plants is the first for Syria. Some cultivated species will be added in the future, because due to the civil war in Syria, it was not possible to visit the country in the frame of the present work, as initially planned. Checklists proved to be a useful tool for overviewing the cultivated plants of selected areas and allow a characterization of the state of plant genetic resources of Syria. Syria has experienced several civilizations. Man settled in this productive land since ancient times and used its resources. However, such use has led to changes in vegetation and decline of wildlife through the country, in seashore areas, interior, mountains, and grassland. Plant domestication and growing started more than 10,000 years ago in West Asia. Since then, plentiful of economic plant species were present and used by man and his domesticated animals. Forming a part of the Fertile Crescent, where many of the world’s agricultural plants have evolved, Syria is extremely rich in agrobiodiversity. Wild progenitors of wheat and barley and wild relatives of many fruit trees such as almonds and pistachio as well as forage species are still found in marginal lands and less disturbed areas. These are threatened by a wide range of human activities, notably modern, extensive agriculture, overgrazing, overcutting and urban expansion. Syria is also considered as part of one of the main centres of origin, according to Vavilov, who had collected in Syria in 1926. The first expeditions to crop fields showed the exclusive nature of cultivated plants in Syria with a high number of endemic forms. Furthermore, Syria is a part of a biodiversity hotspot. Several studies have been performed to study agrobiodiversity in different parts of Syria, but usually on wild species. Many collections have been carried out; however, they focussed preferably on cereals and pulses, and particularly on wheat, like Vavilov’s expedition. Only 30 crops make up the major part of the conserved Syrian crop plant material in the genebank, indicating that most of the remaining 7,000 species of cultivated plants and many other valuable genetic resources species have only been included on a limited scale in the genebank collections. Although a small country (185,180 km2), Syria accommodates numerous ecosystems that allow for a large diversity of plant genetic resources for agriculture ranging from cold-requiring to subtropical crops to live and thrive. Only few references are available in this respect. The aim of the present study was to complete a checklist of Syria’s cultivated plants of agriculture and horticulture excluding plants only grown as ornamental or for forestry. Furthermore, plants taken for reforestation have not been included, if they do not have also agricultural or horticultural uses. Therefore, the inclusion of plants into the checklist follows the same principles as “Mansfeld’s Encyclopedia”. Main sources of information were published literature, floras of Syria, Lebanon and the Mediterranean, as well as Syrian printed sources in Arabic and/or English, reports from FAO on agricultural statistics in Syria, and data from ICARDA and Bioversity International. In addition, personal observations gathered during professional work in the General Commission for Scientific Agricultural Research (GCSAR) in Syria (since 1989) and participation in projects were taken into account. These were: (1) A project on “Conservation and Sustainable Use of Dry Land Agrobiodiversity in the Near East” with participation of Jordan, Lebanon, Syria, and the Palestinian Authority, focussing on landraces and wild relatives of barley, wheat, lentil, alliums, feed legumes, and fruit trees (1999–2005). (2) A project for vegetable landraces (1993–1995) in collaboration with the former International Plant Genetic Resources Institute and the UN Development Programme, in which 380 local vegetable accessions were evaluated. For medicinal plants and fruit trees I was in personal contact with departments of GCSAR and the Ministry of Agriculture and Agrarian Reform, as well as with private organizations. The resulting checklist was compared with the catalogues of crop plants of Italy and a checklist of cultivated plants of Iraq. The cultivated plant species are presented in alphabetical order according to their accepted scientific names. Each entry consists of a nomenclatural part, folk names, details of plant uses, the distribution in Syria (by provinces), a textual description, and references to literature. In total, 262 species belonging to 146 genera and 57 families were identified. Within-species (intraspecific) diversity is a significant measure of the biodiversity. Intraspecific diversity for wild plants has been and remains to be well studied, but for crop plants there are only few results. Mansfeld’s method is an actual logical contribution to such studies. Among the families, the following have the highest number of crop species: Leguminosae (34 spp.), Rosaceae (24), Gramineae (18), Labiatae (18), Compositae (14), Cruciferae (14), Cucurbitaceae (11), Rutaceae (10), Malvaceae (9), Alliaceae (7), and Anacardiaceae (7). The establishment of an effective programme for the maintenance of plant genetic resources in Syria started in the mid-1970s. This programme considered ex situ and in situ collection of the genetic resources of various field crops, fruit trees and vegetables. From a plant genetic resources viewpoint, it is clear that the homegarden is an important location for the cultivation of so-called neglected and underutilized species (neglected from a research side and underutilized from a larger economic side). Such species have so far not received much care from ecologists, botanists and agronomists, and they are considerably under-represented in genebanks.