With over 800,000 dams occurring globally and the construction of thousands more being proposed, successful restoration of regulated rivers will depend on the creation of broadly applicable frameworks that provide management solutions by generalizing patterns in habitat and ecology. Based on the prevailing scientific literature, restoring natural stream flows in disturbed rivers is dependent upon developing quantitative, transferable stream flow-ecology relationships. The purpose of my dissertation was to apply a framework to regulated and unregulated streams within an eight-state region of the southeastern US to test its ability to generalize patterns in natural and altered stream flow and develop flow-ecology relationships. I created a simplified, 5-step version of the Ecological Limits of Hydrologic Alteration (ELOHA) framework (Poff et al. 2010). I carried out each of the steps in sequential order for unregulated and dam-regulated streams found in my region. The steps of my restoration framework are as follows: 1. Develop a natural flow classification of unregulated streams 2. Develop a tool that uses landscape characteristics to predict flow class membership 3. Use the predictive tool or pre-disturbance hydrologic information to classify regulated rivers to natural flow classes 4. Based on class membership, generalize patterns in hydrologic alteration 5. Relate ecological patterns to patterns in hydrologic alteration in relation tomorphology, temperature, and landscape disturbance Altogether, the results of steps 1-4 suggest that patterns in natural flow dynamics and hydrologic alterations can successfully be placed within a framework and generalized to provide the basis and context for environmental flow management; however, results of step 5 suggest that patterns in flow alteration were poorly related to fish assemblages relative to channel morphology, habitat fragmentation, temperature, and substrate. Thus, the development of patterns in hydrologic alteration using the existing frameworks (including mine) may not be ecologically-relevant. My results suggest that current regulated river restoration should not be dependent upon the development of flow-ecology relationships alone, but the interaction between flow, morphology, and temperature within a landscape disturbance context. These relationships should be incorporated within a hierarchical framework to guide restoration efforts in regulated rivers in the future. / Ph. D.

Made available in DSpace on 2014-12-17T14:02:01Z (GMT). No. of bitstreams: 1 WallaceSN_DISSERT.pdf: 4760466 bytes, checksum: 02e9f4b160af4472ebf0590033624755 (MD5) Previous issue date: 2010-06-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning / O bioma Caatinga ? rico em v?rias esp?cies end?micas da ictiofauna. O presente trabalho teve como objetivo verificar a diversidade da ictiofauna da bacia do Rio Piranhas-Assu, RN inserida no bioma Caatinga, alem de verificar os aspectos reprodutivos de uma esp?cie de peixe nativa, piau preto, Leporinus piau (Osteichthyes: Anostomidae). Foram realizadas amostragens mensais entre setembro de 2008 a dezembro de 2009. Foram capturados 602 peixes, distribu?dos em quatro ordens (Characiformes, Perciformes, Siluriformes e Synbranchiformes), 11 fam?lias (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae), e 22 esp?cies, sendo 17 end?micas, quatro introduzidas de outras bacias e uma ex?tica. A ordem Characiformes foi mais representativa em n?mero de esp?cies (46,35%) seguidas por Perciformes (35,38%), Siluriformes (17,44%) e Synbranchiformes (0,5%). A til?pia do Nilo, Oreochomis niloticus, a ?nica esp?cie ex?tica registrada foi mais expressiva em n?mero de indiv?duos (24,92%) seguida pela esp?cie nativa o piau-preto, Leporinus piau (18,77 %). Quando considerado a freq??ncia relativa de ocorr?ncia das 22 esp?cies, 13 foram constantes, cinco acess?rias e quatro raras. Medidas de gest?o ambiental devem ser tomadas para conserva??o das esp?cies end?micas da bacia do Rio Piranhas-Assu do bioma Caatinga. Para investigar os aspectos reprodutivos de peixe nativo piau preto, L. piau, foi capturado um total de 211 exemplares. Os par?metros ambientais, como pluviosidade, temperatura, pH, condutividade el?trica e oxig?nio dissolvido da ?gua foram registradas. A popula??o amostrada mostrou uma leve predomin?ncia de machos (55%) e as f?meas foram maiores em comprimento e mais pesadas. Ambos os sexos de L. piau apresentaram um crescimento alom?trico positivo, indicando um maior incremento de peso do que comprimento. A primeira matura??o sexual dos machos ocorreu mais em tamanho menor, com 16,5cm de comprimento total, do que as f?meas (20,5cm). Durante o per?odo reprodutivo, o fator de condi??o e ?ndice gonadossom?tico (IGS) de L. piau foram correlacionadas negativamente. A esp?cie apresenta ov?citos grandes com uma alta fecundidade (54,966 em m?dia), com desenvolvimento ovocit?rio sincr?nico e desova total