Abbasi, S., M.Sc., University of Saskatchewan, Saskatoon, September 2013. Adaptation to Drought in Saskatchewan Rural Communities: A Case study of Kindersley and Maidstone, Saskatchewan. Joint Supervisors: S. Kulshreshtha and E. Wheaton The main aim of this thesis is to gain knowledge of the processes of adaptation that have enabled communities and agricultural producers to function in a relatively dry and drought prone region of Saskatchewan. This investigation was limited to two rural communities – Kindersley and Maidstone. Historically, vulnerability to natural hazards has been considered only a physical phenomenon. As a result, the social characteristic of a place\system, which contribute to vulnerability to natural hazards, are not well studied. This study used both secondary (quantitative in nature) and primary (qualitative in nature) methods to understand exposure, sensitivity and adaption to droughts in two study communities. Quantitative method included estimating drought condition from time series data for both communities. Intensity of the drought was based on Palmer Drought Severity index and Standard Precipitation Index. Given this background, qualitative techniques (semi-structured interviews and participation observations) were employed to explore the sensitivity and adaptation to droughts in the two communities. The results indicated that drought had caused significant economic hardships for farmers and ranchers during the 2001- 2003 period. Crop yield declined more than 50% of normal level for some crops during this period. Producers had undertaken some adaptive actions to counteract the adverse effect of the drought. These included changing their farming practices -- intensive tillage to minimum or zero tillage, diversification in terms of types of crops grown, off-farm employment, and participation in business risk management programs. Respondents reported that drought was not the sole cause of their vulnerability. Social factors such as changing government policies, reduced profit margins, insufficient business risk management programs, and international markets shaped their vulnerability to climate-related natural hazards. The study found a strong sense of alienation between respondents and federal government agencies. The combination of economic stress, inadequate government risk management programming translates into a very narrow window of sustainability for producers should they face a severe multi-year drought in the future.

The goal of this study was to evaluate the effect of controlled burns, drought and the presence of arbuscular mycorrhizal fungi (AMF) on a dry coastal grassland in Hawai'i Volcanoes National Park. Two introduced African grasses, Hyparrhenia rufa thatching grass, and Melinis repens - Natal redtop, along with one indigenous grass Heteropogon contortus - pili grass composed most of the cover at the study sites. The response of the grasses to fire, AMF infection potential of the soil, and in situ seedling AMF infection were monitored in the field for three years from 1997 to 2000 at Keauhou, Ka'aha, and Kealakomo in Hawai'i Volcanoes National Park. A greenhouse experiment compared the competitive ability of the three grasses with or without AMP inoculation or water stress. The population dynamics of the three grasses were modeled based on their responses to fire, AMF infection, competition and water. At low fire intensities Heteropogon and Hyparrhenia had similar high survival rates while Melinis had a low survival rate. At higher fire intensities all species had low survival rates. The fire decreased the AMF infection potential of the soil at Kaaha, but in situ seedlings AMF infection levels remained high and not statically between the burned and unburned Kaaha sites. In the greenhouse portion of this study Heteropogon biomass increased in response to AMF infection while the other two species did not respond positively to infection. These results suggest that AM fungi increase the growth of the native species, thereby decreasing the impact of competition from two co-occurring alien grasses. When population dynamics were modeled to include the effects of fire, drought and AMF, Melinis and Hyparrhenia produced more biomass in the simulations than the native grass Heteropogon. Drought and AMF decreased the difference in biomass production between the species but did not reverse the competitive ranking of the species.

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Many national parks in Australian rangelands were formerly grazing properties. Even after domestic stock has been removed, the landscapes, especially those near artificial watering points, remained degraded with little or no regeneration of native plants. Congregating large macropods have often been blamed for impeding regeneration of plant communities and rehabilitation of these degraded landscapes. Following a severe drought which reduced densities of large macropods very significantly in Idalia National Park, central-western Queensland, I investigated whether closure of watering points would hamper their recolonisation and influence their grazing distribution and forage selection in the park. I also determined the spatial and temporal pattern of degradation around the watering points, using a suite of indicators. A BACI (Before After Control Impact) type experiment was conducted using two replicate watering points each for impact (fenced) and control (unfenced) treatments. Two watering points were fenced off behind a kangaroo-proof fence in August and December 2002, respectively, in the deepening drought. Walked 4 km line transects were used to estimate densities of red kangaroos (Macropus rufus) and wallaroos (M. robustus) in areas within a 4 km radius of each watering point. The accumulation of dung pellets was used to estimate the grazing distribution of large macropods around water. Abundance and composition of vegetation were monitored on fixed transects using a 0.5 * 0.5 m quadrat 0.5 to 4 km from each watering point. Herbivore offtake was monitored using a movable cage technique. Measures of landscape function (stability, infiltration and nutrient rating) and ant composition were monitored at various distances from each watering point. Monitoring was commenced two to six months before the closure of watering points and completed 21 and 25 months following the closure, every two to five monthly to follow changes in large macropod densities and vegetation communities. Prior to the drought, densities up to 130 large macropods km-2 were recorded in the park. The average density of wallaroos declined by 97.7% during the drought whereas that of red kangaroos declined by 83.8%. The first substantial rain fell in January 2003, but rainfall throughout the study period continued to be much lower than the long-term median, except for January 2004 when more than half the average annual rainfall fell, causing major flooding. Closure of watering points coincident with the drought inhibited red kangaroo recolonisation by 40% in the areas surrounding fenced watering points for up to 21 months following the closure, with distances to alternative watering points being 3.8-6.6 km. Red kangaroos in an area surrounding one of the unfenced watering point recovered to the pre-drought average density. The grazing distribution of large macropods within 4 km from the watering points, however, was determined primarily by where plentiful food resources were, not by the location of water. Large macropods in the areas without access to water did not select forage with higher water contents, compared to those in the areas with water access. Differences in their forage preference between the two areas appeared to reflect the difference in vegetation composition between the areas. Sida filiformis, Cynodon dactylon and Tragus australianus, were identified as grazing sensitive plant species. In some cases, closing watering points helped these plants to increase their abundance following the drought. Most indicators (the percentage of bare soil, biomasses of perennial grasses and round-leaved chenopods, ant functional groups and the measures of landscape function) showed that the exclusion of mammalian grazing for more than a decade from long-term exclosures had facilitated regeneration of perennial grasses and landscape rehabilitation at least at some sites. At one long-term exclosure, where topsoil and seed bank had presumably been lost already, no regeneration occurred. When several indicators were used to determine land conditions around watering points, their responses were not always consistent. Nevertheless, the overall spatial patterns of degradation did not match the spatial pattern of grazing distribution by large macropods around water. Therefore, the current degradation appears to be a legacy of the livestock overgrazing that had continued for more than 100 years prior to the park establishment. The large drought-induced reduction in the large macropod densities did not result in any conspicuous reversal of the patterns of degradation around the watering points.

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 351-360). Also available via the World Wide Web.

Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 151. Thesis director: John J. Qu. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Earth Systems and GeoInformation Sciences. Title from PDF t.p. (viewed June 30, 2008). Includes bibliographical references (p. 135-150). Also issued in print.

The Association for Rural Advancement (AFRA) has run a Drought Project since October 1992. The project's primary focus was to monitor drought conditions in the AFRA's operational area and to assist communities to access relief through providing them with relevant information and helping them to submit proposals to relief agencies. In attempting to do this, it became clear that the effects of drought on rural black communities was not a well understood phenomenon. We also found that relief strategies were informed more by economic, agricultural and meteorological criteria than social ones. This Special Report aims to contribute to the development of a more appropriate drought management strategy, especially with regard to rural communities. In attempting to make this contribution, the Report examines the factors involved in redefining drought and drought relief perspectives in relation to rural communities. However, the range of factors involved and the scarcity of useful information on them, dictate that this is merely an introduction. The complexities and implications arising from the introduction of these factors into drought management in South Africa should be explored on an on-going basis. Because of the scarcity of relevant information about the effects of drought on black rural communities in South Africa, this Report has relied on AFRA's limited monitoring of such communities. Some information was also gathered through Participatory Rural Appraisal (PRA) methods. There were also difficulties in getting information about relief schemes and their operations as most relief agencies were reluctant to release this information. As a result, almost all the relief related information in this Special Report was obtained from publications and reports of the National Consultative Forum on Drought.

Effects of mineral nutrition on drought and cavitation resistance of poplars were examined in two sets of greenhouse-grown trees. First, two drought-sensitive and two drought-resistant hybrid clones of black cottonwood (Populus trichocarpa Torr. & Gray) and eastern cottonwood (P. deltoides Bartr.) were grown at three concentrations of nitrogen (N) applied factorially with two concentrations of phosphorus (P) in a sub-irrigation sand-culture system. The trees were subjected to 0, 4, 6, and 8 days of gradual drought stress before measurements of cavitation, anatomical features affecting cavitation, and nutrient mobilization during drought. High foliar concentrations of N increased cavitation compared to barely adequate concentrations, whereas high concentrations o f P decreased cavitation as measured by both hydraulic flow apparatus and dye perfusion techniques. For one test, cavitation was 48% at high N and low P, but only 28% at high N and high P. Vessel pit membrane mean pore diameters were 0.132 μm at low P and 0.074 μm at high P: smaller pores would decrease air-seeding cavitation. No other significant effects of mineral nutrition on vessel dimensions were observed. Scanning election microscopy showed less damage to pit membranes, suggesting greater membrane strength in drought-resistant clones than in drought-sensitive clones. In the second experiment, three drought-resistant and three drought-sensitive poplar clones (including P. trichocarpa) were grown at two levels of N and three levels of potassium (K) and either well-watered, cyclically droughted, or droughted once. Cavitation, osmotic potential, gas exchange, and nutrient mobilization were measured at each stage of drought and re watering, and fall nutrient retranslocation was monitored. Cavitation was greater with adequate foliar N than at deficiency levels. Moderate supplies of K increased cavitation, but luxury levels sometimes reduced cavitation by decreasing foliar water loss and thus xylem tension. Preconditioning did not reduce vulnerability to cavitation, but there was some evidence of cavitation reversal in a drought resistant clone at high N supply. Vessel diameters were 36.6 μm at low N but 45.2 μm at high N, so within Populus, larger diameter vessels correlated with susceptibility to cavitation. High N supply increased water stress during the first drought, but also increased instantaneous water use efficiency (WUE) before drought occurred, and osmotic adjustment and hardening after drought. Increased K also increased WUE before drought and decreased water stress (decreasing transpiration and wilting) at luxury levels, but did not influence osmotic adjustment or hardening. Mobilization of nutrients differed with speed and intensity of drought. Gradual drought led to resorption of N and P. In the second experiment, drought was too rapid for retranslocation. Nutrients became more concentrated; some (e.g., N) facilitated hardening and osmotic adjustment, and some (e.g., K) moved out of the leaves on re watering. In fall, N, P, Cu and K were resorbed, the latter more proficiently with greater N supply at low levels of K. Clones which were more productive on dry sites resisted severe, but not moderate cavitation. Cavitation-resistant clones maintained high transpiration rates (and less negative water potentials) in drought, especially after hardening, had more, but smaller, stomata and decreased leaf loss in drought, but did not have increased WUE or osmotic adjustment. Nitrogen fertilization increased cavitation, greater P supply reduced this effect, and K fertilization may make vessels more vulnerable to cavitation but decrease the tension on the xylem that causes cavitation. Nitrogen fertilization levels should be tailored to site water supplies, and appropriate P, and possibly K additions may increase drought resistance. / Graduate

Orientador: Marcelo Menossi Teixeira / Texto em português e inglês / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T15:47:59Z (GMT). No. of bitstreams: 1 Farani_TiagoLuz_D.pdf: 5590005 bytes, checksum: 5a826906d504777afc8a4763b6863d0c (MD5) Previous issue date: 2013 / Resumo: A cana-de-açúcar é uma das mais importantes culturas vegetais do mundo, sendo o Brasil o principal produtor. A relevância mundial desta planta tem aumentado e muito tem sido investido na obtenção de variedades de cana-de-açúcar com maiores teores de sacarose e mais resistentes a estresses bióticos e abióticos. O presente trabalho teve como objetivo caracterizar funcionalmente o gene ScCIPK8, relacionado ao acúmulo de sacarose em cana-de-açúcar. Com a finalidade de elucidar as redes de interação da proteína ScCIPK8, ensaios de duplo-híbrido em leveduras foram realizados. Foi identificado que a proteína ScCIPK8 interage com as proteínas ScCBL1, ScCBL3 e ScCBL6, mas não interage com as proteínas ScCBL2, ScCBL9 e ScCBL10. As interações identificadas em leveduras foram confirmadas in planta por ensaios de BiFC. No intuito de identificar alvos de interação diferentes das proteínas CBLs, foram realizados screenings de duas bibliotecas de cDNA transformadas em leveduras. Foram identificadas a interação da proteína ScCIPK8 com as porções C-terminal de uma provável proteína do tipo PP2C e de uma provável proteína MYC2. Avaliamos adicionalmente a resposta à seca do gene ScCIPK8 e dos seus alvos de interação através de ensaios de PCR em tempo real. O gene ScCIPK8 é induzido em uma variedade de cana-de-açúcar tolerante à seca após dois dias de estresse hídrico e é induzido após quatro dias de estresse hídrico, tanto na variedade sensível quanto na tolerante à seca. Por outro lado, o gene ScPP2C-1 é induzido apenas na variedade tolerante à seca após dois dias de estresse hídrico. As expressões dos genes ScCBL1 e ScCBL6 não foram alteradas de forma significativa nas condições testadas. Por outro lado, a expressão do gene ScCBL3 foi reprimida nas plantas da variedade tolerante sob quatro dias de seca e manteve-se inalterado em todas as outras condições testadas. Por fim, plantas transgênicas de Arabidopsis thaliana transformadas com o gene ScCIPK8 foram obtidas e avaliadas quanto à resistência a estresses hídrico e salino. Não foi verificada diferença significativa na tolerância das plantas transformadas com o gene ScCIPK8 em relação aos controles utilizados / Abstract: Sugarcane is one of the most important crop plants in the world and Brazil is the leading manufacturer. The world importance of sugarcane is increasing and much has been invested on obtaining better plants with increasing sucrose content and resistance to biotic and abiotic stresses. The present work aims to characterize the sugarcane ScCIPK8 gene involved in sucrose accumulation. To gain insights on the ScCIPK8 protein-protein interaction network, yeast two-hybrid assays were conducted. It was shown that ScCIPK8 protein interacted with ScCBL1, ScCBL3 and ScCBL6, but not with ScCBL2, ScCBL9 and ScCBL10. BiFC assays were conducted to confirm in planta the interactions observed in yeast cells. Yeast two-hybrid screenings using two different cDNA libraries were conducted to identify unknown targets of ScCIPK8 protein. It was shown that ScCIPK8 interacted with the C-terminal portions of a putative PP2C and a putative MYC2 protein. We also performed qPCR assays in order to evaluate the drought response of ScCIPK8 gene and its target genes. ScCIPK8 gene expression was induced in a tolerant sugarcane variety after two days of drought stress and was induced in both the sensitive and tolerant sugarcane varieties after four days of drought stress. On the other hand, ScPP2C-1 gene expression was induced in the tolerant variety after two days of drought stress. The expression of ScCBL1 and ScCBL6 was not significantly changed under the tested conditions, while ScCBL3 expression was repressed in the tolerant variety after four days of drought stress. Finally, Arabidopsis thaliana transgenic plants overexpressing ScCIPK8 were obtained and evaluated for their resistance to drought and salinity stresses. We could not observe any significant difference regarding drought tolerance between control and transgenic plants transformed with ScCIPK8 / Doutorado / Genetica Vegetal e Melhoramento / Doutor em Genetica e Biologia Molecular

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