Thesis (M.A. - Anthropology)--University of Arizona. / Bibliography: leaves 107-109.

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Prepared for U.S. Army Corps of Engineers, Los Angeles District Office, Contract No. DACW-09-80-C-0071

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abstract: As an industrial society, humans have increasingly separated agricultural processes from natural ecosystems. Many areas of the Southwestern US, however, maintain traditional practices that link agricultural systems to the natural environment. One such practice, diverting river water into fields via earthen irrigation canals, allows ditch water to recharge groundwater and riparian vegetation to prosper along canal banks. As there is growing interest in managing landscapes for multiple ecosystem services, this study was undertaken to determine if irrigation canals function as an extension of the riparian corridor. I was specifically interested in determining if the processes within semi-arid streams that drive riparian plant community structure are manifested in earthen irrigation ditches. I examined herbaceous and woody vegetation along the middle Verde River, AZ, USA and three adjacent irrigation ditches across six months. I also collected sieved hydrochores--seeds dispersing through water--within ditches and the river twelve times. Results indicate that ditch vegetation was similar to streamside river vegetation in abundance (cover and basal area) due to surface water availability but more diverse than river streamside vegetation due to high heterogeneity. Compositionally, herbaceous vegetation along the ditch was most similar to the river banks, while low disturbance fostered woody vegetation along the ditches similar to high floodplain and river terrace vegetation. Hydrochore richness and abundance within the river was dependent on seasonality and stream discharge, but these relationships were dampened in the ditches. Species-specific strategies of hydrochory, however, did emerge in both systems. Strategies include pulse species, which disperse via hydrochory in strict accordance with their restricted dispersal windows, constant species, which are year round hydrochores, and combination species, which show characteristics of both. There was high overlap in the composition of hydrochores in the two systems, with obligate wetland species abundant in both. Upland species were more seasonally constant and abundant in the ditch water than the river. The consistency of river processes and similarity of vegetation suggest that earthen irrigation ditches do function as an extension of the riparian corridor. Thus, these man-made irrigation ditches should be considered by stakeholders for their multiple ecosystem services. / Dissertation/Thesis / M.S. Biology 2010

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Made available in DSpace on 2017-07-10T14:38:19Z (GMT). No. of bitstreams: 1 jislaine.pdf: 1680477 bytes, checksum: fd1ff3624e2ae8e46f1e311b5237e545 (MD5) Previous issue date: 2013-08-05 / Variations in spatial and temporal scale in the provision of food resources play a central role in changing patterns of food utilization by fish species. Thus, the aim of this study was to evaluate the spatial and temporal variations in the use of food resources for species of small fish in the Verde River, the Upper Paraná River basin, Mato Grosso do Sul. Samples were collected during the rainy season and dry from November 2010 to August 2012, using trawls, cast nets and gillnets. Nine sampling sites were grouped into three biotopes: upstream and downstream of the Branca Waterfall and tributarie. The stomach contents of 3,263 individuals belonging to 12 species of small size were analyzed according to the volumetric method. Altogether 31 food items were recorded. For all biotopes analyzed the consumption of seeds was higher in the rainy season, and plant (leaves) in the dry season. Hymenoptera was an important item in the diet of fish species, but the proportions were different in consumption between periods and biotopes. The consumption of Coleoptera and Isoptera was significant only in the downstream Branca Waterfall in the rainy season and aquatic plant was consumed more in tributarie in the dry season. The Principal Coordinate Analysis (PCoA) and indicate spatial and temporal segregation of species in the diet, showed the interaction between these two factors. Significant differences were observed in the composition of the diet among biotopes, rainy and dry seasons and interaction. Resources allochthonous origin was clearly the most consumed by the species in all biotopes in both hydrological periods. The dietary overlap between species, even with significant seasonal and spatial differences, was considered low (< 0.4 ) for about 60 % of species pairs . Thus, we conclude that spatial and seasonal changes occurred in the use of food resources for species of small fish and these variations were related to differences physiographic channel and environment that contributed to seasonal changes in the diet were significant, reflecting also the low overlap feed between species / Variações em escala espacial e temporal na oferta dos recursos alimentares desempenham um papel central nas alterações dos padrões de utilização dos alimentos pelas espécies de peixes. Dessa forma, o objetivo deste estudo foi avaliar as variações espaciais e temporais no uso dos recursos alimentares pelas espécies de peixes de pequeno porte no rio Verde, Bacia do Alto rio Paraná, Mato Grosso do Sul. As coletas foram realizadas no período chuvoso e seco, de novembro de 2010 a agosto de 2012, utilizando arrastos, tarrafas e redes de espera. Foram nove locais de amostragem, agrupados em três biótopos: montante e jusante da Cachoeira Branca e tributário. Os conteúdos estomacais de 3.263 indivíduos pertencentes a 12 espécies de pequeno porte foram analisados de acordo com o método volumétrico. Ao todo foram registrados 31 itens alimentares. Para todos os biótopos analisados, o consumo de sementes foi maior no período chuvoso, e vegetal (folhas) no período seco. Hymenoptera foi um item importante na dieta das espécies de peixes, porém as proporções no consumo foram distintas entre os biótopos e períodos. O consumo de Coleoptera e Isoptera foi expressivo apenas na jusante da cachoeira branca no período chuvoso e vegetal aquático foi mais consumido no tributário na estação seca. A análise de coordenadas principais (PCoA) além de indicar segregação espacial e temporal na dieta das espécies, evidenciou a interação entre estes dois fatores. Diferenças significativas foram verificadas quanto à composição da dieta entre os biótopos, períodos chuvoso e seco e para a interação. Recursos de origem alóctone foram nitidamente os mais consumidos pelas espécies em todos os biótopos em ambos os períodos hidrológicos. A sobreposição alimentar entre as espécies, mesmo apresentando diferenças espaciais e sazonais significativas, foi considerada baixa (<0,4) para cerca de 60% dos pares de espécies. Assim, podemos concluir que ocorreram mudanças espaciais e sazonais no uso dos recursos alimentares pelas espécies de peixes de pequeno porte e essas variações estiveram relacionadas às diferenças fisiográficas do canal e entorno que contribuíram para que mudanças sazonais na dieta fossem significativas, refletindo também na baixa sobreposição alimentar entre as espécies