The research concerns the potential for using the native plants of the Negev Desert in southern Israel in the Negev, which will help to promote more sustainable landscape development in the region. The study combines the data collection in the field of 163 plant species located in the Negev desert and the literature review of these species. The plants’ key physical, visual and aesthetic characteristics as well as their natural growing conditions are analysed. The analysis leads to an evaluation of the Negev plants in terms of suitability for particular uses in the Negev landscape. The conclusion reached is that the main reason for the non-use of the native plants is that they are still considered a part of the hostile desert environment. They have not as yet been ‘culturalised’. The advantages/disadvantages of using the native plant species is considered for each plant using a natural/quasi-experimental method, where each of the 163 species located by the author is analysed in terms of its physical and aesthetic characteristic and potential use. Furthermore, the individual species are matched with an exotic species and evaluated according to their potential landscape and ecological effects, water use and their potentials for environmental use in natural areas, the middle landscape and garden locations. The analysis and evaluation of the native Negev species confirms that 95%-96% of the native Negev plants have the potential for environmental use in natural areas and the middle landscape and 69% have the potential for garden use. A scientific study of the shade characteristics of 6 native Negev trees confirms that these trees provide an equal, if not better shade, compared to two control species and thus their potential for use in creating shade and altering micro-climate has been proven. The research also proposes a series of micro-landscape solutions, which will help to promote plant establishment and growth in the Negev as well as other desert environments. These proposals are seen as part of the agenda for establishing more sustainable landscape development in the Negev.

Climate change is caused by rising quantities of greenhouse gases, particularly CO2, in the atmosphere, largely through consumption of fossil fuels. There is interest in sustainable energy generation from renewable resources, particularly biomass crops to reduce reliance on fossil fuels. A key advantage of such energy systems is that they assimilate atmospheric CO2 and thus help mitigate climate change. Soil represents one of the largest pools of C in the biosphere and there is potential to use soil as a sink to sequester C to mitigate climate change. The aim of this project was to investigate soil C storage and sequestration in short rotation coppice (SRC), which is one of the major biomass cropping systems in temperate climates. 14 year old plantations of willow and poplar established at Rothamsted Research in Harpenden were used to investigate how the quantity and quality of organic matter under the SRC compare to that under adjacent land uses, including arable cropping, set-aside grassland and natural woodland. It was shown that change in land use to SRC led to increased C storage in soil relative to alternative agricultural systems, while conversion to setaside had no effect on soil C stocks. There was no difference in C storage under different poplar or willow cultivars. Differences in C storage between arable, SRC and set-aside plots reflected changes in C stocks at 0-30 cm depth with no change occurring to C at 30-60 cm. The quality of C was investigated by analysis of the light fraction organic matter pool which acts as an early indicator of long term changes in total soil organic matter. The work showed that the free LFOM pool responded to land use change while the physically protected intra-aggregate LFOM pool did not. While changes to amounts of LFOM following land use change occurred in soil at 0-30 cm depth, there were no changes at 30-60 cm depth. Fourier Transform Infra Red spectroscopy showed that the chemical composition of free and intra aggregate LFOM was different, and that composition of both pools was affected by land use. Fourier Transform Ion Cyclotron Resonance Mass spectroscopy was shown to provide fine level resolution of the composition of soluble organic matter, and demonstrated that the aromaticity and chain length of C was higher in woodland than arable soil. The potential to sequester C in soil as biochar is a promising option to promote longterm sequestration of C in soil. The potential to use a fluidised bed reactor to produce biochar was investigated. Life Cycle Analysis showed that 4700C was the optimal temperature to promote retention of C in biochar during pyrolysis, while minimising losses of C as bio-oil and gases. Addition of steam during pyrolysis was shown to increase the surface area of the resulting biochar. Addition of biochar to soil reduced net C mineralisation of soil organic matter and litter at a rate of 2 % w/w, but not at 0.5 % w/w. However both concentrations of biochar affected net mineralisation of N. Phospholipid fatty acid analysis showed that both concentrations of biochar altered microbial community structure, with fungal biomass in particular promoted by the addition of biochar. Overall the work demonstrates that SRC promotes significant storage of C within soil organic matter, which has implications for the overall energy budget of SRC biomass. Furthermore, conversion of biomass to biochar for land application provides opportunities for sequestration of C within soil. Application of biochar to soil would provide further benefits to the overall energy balance of SRC by reducing mineralisation rates of native soil organic matter and litter.

Management strategies were compared, including thinning and the production of fuelwood versus larger size-class volume, to develop a management plan for the mesquite woodland of the southern Arizona study site. Pre-commercial thinning of mesquite stands is not economic and the production and separate marketing of the larger size class at current stumpage rates gives only marginally higher returns than fuelwood alone, $9.57/ha/yr compared to $9.13/ha/yr. Equations were developed for prediction of fuelwood volume and for estimating volume in stem pieces 20 cm or greater in diameter. Estimated growth rates were 0.43 m3/ha/yr for the upland areas and 0.84 m3/ha/yr for the riparian areas. The culmination of mean annual increment suggests a rotation age of 40 years.

The influence of the herbicides sulfometuron and simazine on the establishment of 8 species of tree seedlings was studied in northern Israel. The experiment included three treatments and a control. The first treatment applied simazine at a rate of 5 kg/ha, and second treatment applied simazine at a rate of 5 kg/ha and sulfometuron at a rate of 0.03 kg/ha. Sulfometuron was applied alone at a rate of 0.03 kg/ha in the third treatment. Statistical analyses showed significant effects on the survival of some species treated with sulfometuron. To ensure earlier season survival, the rate of sulfometuron applied should be kept at a minimum level to allow both weed control and adequate establishment of seedling. Low-rate applications are particularly important in arid and semi-arid areas.

I examined movements and habitat use by desert mule deer (Odocoileus hemionus crooki) and collared peccary (Dicotyles tajacu) in the Rincon Mountain District of Saguaro National Monument (SNM) from February 1988 through December 1989. Movements and habitat use by mule deer were closely associated with the distribution of free-standing water during the driest seasons of the year. Deer responded to losses of ephemeral water sources in SNM by leaving the monument to obtain water. Four of 5 peccary herds supplemented their natural diet by visiting houses and/or restaurants on a daily or twice daily basis. The addition of water and supplemental food sources was a deliberate effort by homeowners to attract wildlife onto their property. The current pattern of habitat islands interspersed with low density housing (1 house/2-4 ha) is an effective and highly desirable buffer zone between the monument and the more heavily developed urban areas 3.2 km west of the park.

The Hayden-Rhodes Aqueduct (HRA) extends from Lake Havasu along the California and Arizona border to 40 km northeast of Phoenix, Arizona. The Bureau of Reclamation established water catchments for wildlife, and wildlife bridges to provide access for wildlife across the HRA. I investigated the effectiveness of these mitigations for desert mule deer (Odocoileus hemionus crooki) from July 1989 to July 1990. I examined deer use of wildlife bridges, concrete overchutes, and water catchments; the quality of deer habitat at crossings; and the influence of mountain lions (Felis concolor) on deer at water catchments. All water catchments were used by deer. There was very little use of wildlife crossings by deer. Deer habitat on the north side of the HRA received more use by deer than habitats south of the HRA. I could not determine if mountain lions capture prey more often near water catchments than in other areas.

I sought to determine if brown tree snakes (Boiga irregularis) raised in captivity showed annual and/or subsidiary growth marks corresponding to feeding or shedding events. I injected 25 brown tree snakes with a fluorescent bone marker (calcein or alizarin red) and raised them for one year under constant conditions. Growth marks beyond the fluorescent marker were correlated with shedding events but not with years or feeding events. Shedding events have not previously been identified as a correlate of growth marks in bone. I do not know if the correlation occurs in other species, as growth cycles have not previously been studied in tropical snakes. The correlation between growth marks and shedding events may allow the study of ecdysis in free-ranging snakes, and shedding events may be the cause of the secondary growth marks found in many reptiles.

Measurements of tree characteristics were used as indicators of overstory structure on four oak woodland sites in southeastern Arizona. Three areas harvested at different times and intensities were compared with an undisturbed area to assess effects of harvesting on various structural attributes of woodland overstories. Structural vegetation changes affect habitat quality and thus wildlife populations in modified areas. Significant differences were found for some woodland structural characteristics between harvested areas and an undisturbed area. Structural changes persist, as prolific coppice sprouting produces shrub-like trees, which appear to take a relatively long time to reach mature height and form. Managers might be able to moderate impacts of harvests on woodland structure by adjusting harvest intensity, and multiple-use management objectives for some species of wildlife still might be met.

I examined the relationship between exotic and native cavity-nesting birds in the Sonoran desert near Tucson, Arizona during 1988 and 1989. I attempted to limit cavity availability in 1989 by plugging cavities that were unused, or used by exotics, in 1988 with rubber test tube stoppers. Numbers of nests of any species did not significantly change between 1988 and 1989. Control plots showed similar results. I found no significant negative correlations between number of nests of European starlings (Sturnus vulgaris) and any other cavity-nesting species. Of the cavity characteristics examined, species only differed in size of cavity openings. My data indicate that exotic and native cavity-nesting birds were not competing for nest cavities. An excess of available nest cavities is the probable reason for this lack of competition. Temporal differences in cavity use among species may have helped contribute to the abundance of cavities.

Habitat use of Merriam's turkey (Meleagris gallopavo merriami) was characterized in the Prescott National Forest, Arizona, between March 1991 and August 1992. Roost sites were generally found in canyons or on hillsides, and contained a large number of ponderosa pine trees, and Gambel oak seedlings and trees. Turkeys fed on juniper berries, generally in small groups of large juniper trees within ponderosa pine stands. Turkeys fed on acorns in stands of Gambel oak on hillsides. Turkeys feeding on grass/forb vegetation tended to be on flat areas with a large amount of forb and grass cover. Turkeys loafed under Gambel oak, in areas with large amounts of Gambel oak growth near openings, on hillsides or in canyons. Turkeys also loafed under juniper trees; these areas had a large basal area of alligator juniper and high numbers of Gambel oak seedlings.