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Predators exert strong direct and indirect effects on ecological communities by intimidating their prey. Non-consumptive effects (NCEs) of predators are important features of many ecosystems and have changed the way we understand predator-prey interactions, but are not well understood in some systems. For my dissertation research I combined a variety of approaches to examine the effect of predation risk on herbivore foraging and reproductive behaviors in a coral reef ecosystem. In the first part of my dissertation, I investigated how diet and territoriality of herbivorous fish varied across multiple reefs with different levels of predator biomass in the Florida Keys National Marine Sanctuary. I show that both predator and damselfish abundance impacted diet diversity within populations for two herbivores in different ways. Additionally, reef protection and the associated recovery of large predators appeared to shape the trade-off reef herbivores made between territory size and quality. In the second part of my dissertation, I investigated context-dependent causal linkages between predation risk, herbivore foraging behavior and resource consumption in multiple field experiments. I found that reef complexity, predator hunting mode, light availability and prey hunger influenced prey perception of threat and their willingness to feed. This research argues for more emphasis on the role of predation risk in affecting individual herbivore foraging behavior in order to understand the implications of human-mediated predator removal and recovery in coral reef ecosystems.

Livestock production is one of the largest and fastest growing agricultural subsectors in the world, contributing almost 40 % of agricultural GDP. The present global trend of livestock intensification affects water demand, resulting in local alterations of hydrological features. This study quantifies water requirements for livestock production and links them to local changes in water-related ecosystem services (WRES). It examines the present situation in Uruguayan beef production as it undergoes an intensification process by analyzing three systems: traditional extensive production, mixed systems and intensive production.Mixed production systems are most water-effective in terms of water requirement. However, extensive production has the least negative long-term effects on the studied WRESs: soil productivity, erosion control and grass, crop and livestock production. Intensive systems contribute the largest negative impacts on soil productivity due to management practices, e.g. continuous cropping and fertilizer application (which is also costly). However, intensification also increases short-term positive effects on crop and livestock production. Mixed systems offer opportunities to increase livestock production, water use efficiency and mitigate soil degradation. However, a threshold value to avoid an undesirable regime shift in soil productivity remains to be determined.This framework developed herein, maps and quantifies local ecosystem effects associated with livestock production from a water perspective. It required simplifications and thus needs further improvements to be of practical use as a tool for best management practices of livestock production. Such tools can assist decision-makers in Uruguay on how to manage multiple ecosystem services in an agricultural landscape and enhance the provision of desired ES without degrading other key ecosystem processes, goods and services. For sustainable production of livestock in Uruguay, one should consider if the tradeoff between long-term negative impacts of intensification on regulating services is justifiable in the context of the short-term economic gains in provisioning services.

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Predators can have large effects on prey populations and on the structure and function of communities. In addition to direct consumption of prey, predators often cause prey to alter their foraging behavior, habitat selection, and morphology. These non-lethal effects of predators can propagate to multiple trophic levels and often exert equal or larger effects upon communities than those of direct consumption. For non-lethal predatory effects to occur, prey must detect and respond to predation risk. While the importance of information transfer in this process has been realized, few studies explore how prey responses are influenced by predator characteristics and environmental conditions that influence the transmission of cues indicative of predation risk. In this dissertation I investigate factors that influence how a single prey species evaluates and responds to predation risk. Here, I examined: 1) the type and nature of cues prey use to evaluate predator risk; 2) how predator identity, predator diet, and the relative risk of predators influence prey response to predation risk; 3) how hydrodynamic conditions influence the delivery of predator cues; 4) how biogeographic trends in predator distribution influence prey response to predation risk; and 5) how genetic structure might vary according to prey geographic location and habitat. To address these questions, I used a common intertidal model system consisting of the rocky intertidal whelk Nucella lapillus (Linnaeus, 1758) and a suite of its predators, the native rock crab Cancer irroratus (Say, 1817), Jonah crab Cancer borealis (Stimpson, 1859), and the invasive green crab Carcinus maenas (Linnaeus, 1758). Nucella use chemical cues emanating from their most common predator (Carcinus maenas) and crushed conspecifics to evaluate predation risk. Nucella from different habitats experience different levels of predation risk, and Nucella from habitats with high levels of predation had larger antipredatory responses to predator risk cues than Nucella that experienced less predation. These chemical cues indicative of predation risk are influenced by hydrodynamic conditions, and Nucella have the strongest anti-predatory response in flow velocities of u= ~4- 8 cm s^-1. Furthermore, Nucella from geographic regions where green crabs are historically absent did not elicit anti-predatory responses, while Nucella from regions where green crabs are common frequently responded. Findings from my dissertation research demonstrate that prey detection and response to predation risk is highly dependent upon predator identity, predator diet, environmental forces, and biogeographic patterns in predator and prey distributions.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Relative water content (RWC), water potential (P), and gas exchange were measured on saltcedar at the Bernardo, New Mexico, lysimeter site. RWC and s were closely correlated; but, water potential measurements, taken with a pressure bomb, were more convenient and reliable. RWC and r decreased sharply from sunup until about 0900, when minimum values of about -26 bars T or 80% RWC were reached. Water status then remained constant or improved slightly through late afternoon. Transpiration rates typically remained high until about noon and then began a steady, gradual decrease that continued throughout the afternoon. The data suggest that water stress may be a factor in initiating stomatal closure; however, transpiration continued to decline despite a constant or improved leaf water status. Maximum net photosynthetic rates occurred by 0900, and depressions throughout the remainder of the day were largely accounted for by increased leaf temperatures. Afternoon depressions in transpiration and photosynthesis occurred in twigs held at constant temperature and relative humidity, suggesting that a diurnal rhythm may be involved in control of gas exchange. Water status of plants growing on the lysimeters was comparable to that of plants in adjacent natural stands; gas exchange rates were slightly higher for the lysimeter-grown plants.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Tucson's "Beat the Peak" program implemented in the summer of 1977 effectuated a reduction in peak day water usage from 151.5 million gallons per day on July 9, 1976, to 114.0 million gallons per day on July 8, 1977. This twenty-five percent reduction, if maintained, will allow a three -year deferral of a new remote wellfield and transmission pipeline estimated to cost between $25 and $50 million. More time will be available to analyze the cost effectiveness of solutions to the region's water resources supply problems (such as imported groundwater, Central Arizona Project water, effluent reuse, and their interrelationships). Although conservation was not promoted, the successful peak management program resulted in a 13.3 percent reduction in 1977 water use during the summer months (May through August) compared to usage during the same period in 1976. This resulted in water sales revenues less than projected, but the combination of less utility expenses and deferred capital improvements will yield lower customer rates and monthly bills than would have otherwise been necessary without the program.

A water footprint is a tool for assessing the impacts of freshwater use by mapping the water use of the production of a good or a service, a process in a production chain, a business or even of a whole country. One of the most commonly used methods for calculating the water footprint was developed by the Water Footprint Network (WFN). The objective of this study was to account for the water footprint of the production of coffee in the area of Miraflor, Nicaragua, using the WFN method. The study aimed to highlight where improvements can be made regarding water resources management, both with respect to the quantity of the water appropriated in the different process steps, as well as concerning the treatment of residues of the coffee production. The results of the study show a water footprint of 20 049 m3 per ton of harvested coffee in Miraflor. This equals a consumption of more than 6 000 000 m3 of water when considering the overall production of the harvest of 2015/2016. The results pinpoint the growing phase as crucial with 98.1 % of the total water footprint. Nicaragua and the region where Miraflor is located are having increasing problems with water scarcity due to drought and contamination of water resources. Together with these circumstances, the results of the study show that the current management should be improved in order to minimize the impacts on local water resources and the environment. It is mainly the application of pesticides and fertilizers in the cultivation of the coffee that give rise to the large water footprint. Furthermore, the current management violates the law restricting the discharge of effluent waters from coffee processing plants. Another important factor contributing to the water footprint yields in the consumption of rainwater via evapotranspiration by the crops in field. In order to reduce the water footprint there should be a more conscious use of pesticides and fertilizers as well as a development in the treatment of the effluent water. The latter factor can be elaborated by considering new installations where even smaller ones probably could make a considerable change. Other management practices to decrease the water footprint consist of generating a higher yield per hectare of land. / Vattenfotavtryck är ett verktyg för att bedöma miljöpåverkan från användningen av vatten. Med ett vattenfotavtryck kartläggs hur vatten används för produktionen av en vara, för en process i en produktionskedja, ett företag eller för ett helt land. En av de mest använda metoderna för beräkning av vattenfotavtryck utvecklades av Water Footprint Network (WFN). Syftet med denna studie var att genom användning av WFN:s metod beräkna vattenfotavtrycket för produktionen av kaffe i området Miraflor i Nicaragua. Studien ämnade visa var förbättringar kan göras i vattenresurshanteringen, både vad gäller mängden vatten som används i de olika produktionsstegen som i behandlingen av restvattnet från kaffeproduktionen. Resultatet från studien visar ett vattenfotavtryck på 20 049 m3 per ton skördat kaffe i Miraflor. Sett till hela skörden för säsongen 2015/2016 ger detta ger en total konsumtion av mer än 6 000 000 m3 vatten. Resultatet påvisar att vegetationsperioden är den i särklass största bidragande faktorn till kaffeproduktionens vattenfotavtryck med 98,1 % av det totala avtrycket. Nicaragua och regionen där Miraflor ligger har alltjämt ökande problem med vattenbrist på grund av torka och föroreningar av vattenresurser. Studiens resultat visar tillsammans med denna bakgrund att nuvarande tekniker i kaffeproduktionen i Miraflor bör förbättras för att minimera konsekvenser för lokala vattenresurser och miljön. Främst är det användningen av bekämpningsmedel och gödsel som ger upphov till det stora vattenfotavtrycket. Kaffeproduktionen orsakar därtill överträdelser av gällande bestämmelser om värden på vattenkvalitetsparameterar i restvatten från kaffeproduktion. En ytterligare betydande faktor för vattenfotavtrycket som påvisas i studien är konsumtionen av regnvatten via evapotranspiration från grödorna i fält. För att minska vattenfotavtrycket bör i första hand en mer medveten användning av bekämpningsmedel och gödsel införas. Därtill bör det ske en förbättring i hanteringen av utsläppsvatten. Den senare faktorn kan utvecklas genom att nya installationer införs där även mindre sådana troligtvis skulle ge en betydande skillnad. Andra metoder för att minska vattenfotavtrycket ligger i att generera en högre skörd per hektar land.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Transpiration rates (T) of riparian phreatophytes can be high. Antitranspirant (AT) sprays can curtail T without the ecological imbalance made by eradication. Saltcedar (Tamarix sp.) and cottonwood (Populus sp.) in 15-gal. drums enabled replicated trials on isolated plants or on canopies. T of isolate saltcedar plants could be 2x that of plants in a fairly dense canopy. T for a unit ground area of saltcedar varied from 2.2 (sparse -) to 15.8 (dense-stand) mm/day in July at Davis. Extrapolation of experimental T data to field sites must, therefore, be made carefully. Wax -based ATs increased foliar diffusive resistance (R), and reduced T of saltcedar and cottonwood 32-38% initially and 10% after 3 weeks. R increased naturally in the afternoon when evaporative demand was high and if soil water was low. Nocturnal T of salt cedar was 10% of day T. AT effectiveness increased with a higher ratio of day: night hours, and with lower soil water stress. Therefore, AT will be most effective on long summer days in riparian areas where ground water is available.

Water constraints for humans and nature are gaining more and more public attention as a critical environmental dilemma that needs to be addressed. When aquifers and rivers are running dry, the debate refers to an ongoing “world water crisis”. This thesis focuses on the water and agricultural production complexity in a global, regional and local perspective during different phases of development. It addresses the river basin closing process in light of consumptive water use changes, land use alterations, past and future food production in waterscarce developing countries in general, and a south Indian case study basin in particular, the Bhavani basin in Tamil Nadu. The study focuses on early phases of global agricultural development and addresses consumptive use and river depletion in response to land use change and irrigation expansion. It shows that focus must be shifted from a water use to a consumptive water use notion that considers both green and blue water resources. The Bhavani basin development trajectory reveals a dynamic interplay between land and water resources and different socio-political groups during the “green revolution” period. The present system has emerged as a step-by-step adaptation in response to hydro-climatic variability, human demands and infrastructure constraints. The study reveals three kinds of basin closure: allocation closure; hydrological closure; and perception wise closure. Many concerted actions on multiple scales have contributed to an increasing water use complexity even after closure. The study shows the extent to which natural variability hides creeping changes, and that the “average year” is a deceptive basis for water allocation planning. Future consumptive water requirements to feed growing populations in the developing world is analysed with a back-casting country-based approach. The study shows a doubling of water requirements by 2050 and how the challenge can be halved by increased water productivity. Since blue water accessibility for irrigation clearly will be insufficient, additional green water has to be acquired by horizontal agricultural expansion into other terrestrial ecosystems. The task will be substantial and increase the importance of global food trade. / Vattenbrist för människor och ekosystem är en mer och mer uppmärksammad miljöfråga. Sjunkande grundvattennivåer och uttorkade floder gör att många talar om en ”global vattenkris”. Denna avhandling fokuserar på de komplexa sambanden mellan vatten och jordbruksproduktion utifrån ett globalt, regionalt och lokalt perspektiv under olika utvecklingsfaser under fyra sekler. Den redogör för hur avrinningsområden överintecknas och slutligen ”stängs” för ytterligare vattenutvinning. Effekterna av ökad vattenutvinning i relation till historisk och framtida matproduktion analyseras generellt i utvecklingsländer med vattenbrist, och i detalj i en fallstudie i Bhavani avrinningsområde i Tamil Nadu i södra Indien. Studien visar för den tidiga jordbruksutvecklingen på global nivå hur förändrad markanvändning och bevattningsexpansion leder till förändrad balans mellan evapotranspiration och avrinning, med uttorkning av vattendrag som följd. Den visar vidare vikten av ett paradigmskifte där fokus flyttas från vattenanvändning till ”konsumerande” vattenanvändning, och som inkluderar både grönvatten- och blåvattenresurser. Analysen av Bhavaniområdets utvecklingskurva under det senaste seklets jordbruksutveckling visar på ett dynamiskt växelspel mellan land- och vattenresurser och mellan olika samhällsgrupper. Den nuvarande vattenanvändningssituationen har stegvis växt fram som en respons på hydroklimatisk variabilitet, människors behov och infrastrukturbegränsningar. Studien påvisar att ett avrinningsområde kan ses som ”stängt” på tre skilda sätt: när flödet är överintecknat, när utflödet sinar, och när vattenanvändare upplever att behoven överstiger tillgången. Även efter ”stängning” har etablering och intensifiering av vattenutvinning fortsatt och resulterat i ett alltmer komplext och sammanflätat vattenanvändningsmönster. Studien visar vidare hur hög hydroklimatisk variabilitet, dels gör att ”genomsnittlig vattentillgång” är förledande vid planering av vattenfördelning i ett avrinningsområde, och dels döljer smygande kumulativa effekter av ökad vattenutvinning. Slutligen anlyseras ländervis framtida vattenbehov för att möta matbehovet i världens utvecklingsländer, vilket visar på en fördubbling fram till 2050. Tack vare ökad vattenproduktivitet kan behovet emellertid halveras. Endast en bråkdel av det resterande behovet kan mötas genom ökad bevattning, dvs. med mera blåvatten. En stor del av vattenbehovet måste istället täckas med mera grönvatten via uppodling av andra terrestra ekosystem. Uppgiften innebär en betydande utmaning och global handel med jordbruksprodukter kommer att öka avsevärt i betydelse.