Seven streams, one of them permanent, were studied in western Oregon, USA. The research was designed to assess the value of summer-dry headwaters for conservation oriented landscape management. Streams were categorized primarily according to exposure (forest versus meadow sites) and secondarily according to flow duration (ephemeral = short-flow versus temporary = long-flow sites). Ephemeral streams have discontinuous flow and last less than three months annually. Temporary streams have continuous flow for more than five months each season. Ephemeral forest streams were highly efficient at filtering road-generated sediment. Uptake lengths for suspended sediment were short (36 m-105 m) at moderately elevated input concentrations. As a result of the filtration mechanism, filtration efficiency is expected to increase as annual flow duration decreases. Injection experiments yielded nitrate uptake rates of almost 1% per m of temporary stream channel. Exchange with subsurface flow was the most important route for nitrate removal from the water column. Biological uptake was insignificant in a light-limited forest stream, whereas a considerable amount of nitrate was retained by the biota a nutrient-limited meadow channel. At least 207 insect species were collected from the summer-dry streams. Species richness recorded from temporary forest streams exceeded that in an adjacent permanent headwater and there was high overlap between the fauna of the permanent and the temporary streams. Species richness in ephemeral channels was only 1/4 to 1/3 of that in long-flow forest streams. Multivariate analysis of community structure revealed flow duration and microhabitat pattern (riffle-pool) as the most important environmental factors determining faunal composition in temporary forest streams. Summer drought conditions at the sample sites also were important. By providing habitat and contributing to water quality in permanent downstream reaches, summer-dry streams have the potential to serve multiple purposes in conservation management. Their value from a conservation perspective is unexpectedly high. Landscape management therefore should be directed toward the preservation and protection of ephemeral and temporary streams. / Graduation date: 1993

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 98-106). / vii, 106 leaves, bound 29 cm

A study of the aquatic invertebrate communities from two locations (Location 1 and Location 2) within the Matapouri catchment in Northland, New Zealand, was conducted to assess community structure in differing local-scale habitats. Four data collection methods were utilised generating 33,058 adult or larval invertebrates. The sampling methods comprised benthic kick-sampling, sticky trapping, light trapping, and emergence trapping. For the sticky trapping and light trapping, sampling was carried out at three different sites (Sites 1–3) within each location. The sites were situated within three habitat types; native forest, native forest-fringe, and raupo wetland. Emergence trapping also commenced within the three sites, at both locations, but was discontinued after two months, due to the equipment being destroyed by consecutive flooding events (method described in Appendix 1). Benthic sampling was carried out within the Forest and Forest-fringe habitats. Benthic sampling, sticky trapping, and light trapping were carried out following a monthly schedule between June and November 2005. Conductivity, pH, and water temperature measurements were taken concurrently with benthic sampling on a monthly basis, while water velocity and substrate measurements were taken once to assist in habitat characterisation. Overall, 71 taxa were recorded by benthic sampling over the six month period, with a mean of approximately 30 taxa per site per month. In comparison with similar studies elsewhere in New Zealand, a figure of around 30 taxa per sample was high. The benthic macroinvertebrate fauna at all sites was dominated by Trichoptera (19 taxa), Diptera (16 taxa) and Ephemeroptera (10 taxa). This pattern of diversity is similar to that reported in other New Zealand studies. However, in contrast to previous studies, the leptophlebiid mayfly genus Deleatidium was not numerically dominant over the rest of the community, and other leptophlebiid genera (Acanthophlebia, Atalophlebioides, Mauiulus and Zephlebia) were equally represented, possibly reflecting niche partitioning between the groups. The genus Nesameletus was not recorded at any site, despite being one of the core mayfly species in New Zealand streams. The rare mayfly Isothraulus abditus was recorded at one of the forest locations. There are no published records of this species from Northland. Although acknowledged as another of the core New Zealand benthic taxa, the hydropsychid caddisfly Aoteapsyche was not recorded during the study. However, another hydropsychid, Orthopsyche, was commonly recorded, and these may be filling a similar niche to the Aoteapsyche genus. In contrast to the Trichoptera, Diptera, and Ephemeroptera, the Plecoptera fauna was relatively depauperate, probably reflecting the warmer climate of the region and lack of temperature-buffered spring-fed streams. Surprisingly, Zelandobius, a core New Zealand genus, was absent but is regularly recorded in Northland. A species of conservation interest, Spaniocercoides watti, currently recognised as a Northland endemic, was recorded in low numbers. There were no apparent trends in diversity or abundance of benthic invertebrates over time. Also, there were no significant differences in species diversity between the two locations. However, in many cases, taxa were more abundant at Location 2. This may have been due to steeper gradients at Location 2, and the consequent effects on substrate size and streambed stability, as all other physical factors appeared similar between locations. Although several significant differences of individual benthic taxa were recorded, no broad effect of habitat (sites) on species diversity was observable. However, at Location 2, abundances were significantly higher at Site 3 (Forest) compared to Site 2 (Forest-fringe). The reasons were uncertain, but may be attributed to higher retention of allochthonous organic materials, trapped by in-stream cover and larger substrates. Investigations of adult stages by sticky traps supported benthic results recording community compositions and abundances dominated by Trichoptera and Diptera. Plecoptera were poorly represented. Location 2 recorded higher abundances of taxa, particularly Ephemeroptera and Plecoptera. Investigations of adult stages by light traps however did not produce any statistically significant differences in abundances between sites, between locations, or between sites across locations, and it is believed to be due to limited sampling replication combined with some biases of light trapping. This study indicates that the aquatic invertebrate community at Matapouri is diverse but also reasonably representative. Several rare or uncommon insects inhabit the catchment. It is therefore important that Iwi and the local Landcare Group, who invited and supported this research, together with the Department of Conservation, continue their efforts in protecting these areas. The resident fauna have the capacity to restock areas downstream, which are intended to be improved and restored through sediment control and riparian management.

A study of the aquatic invertebrate communities from two locations (Location 1 and Location 2) within the Matapouri catchment in Northland, New Zealand, was conducted to assess community structure in differing local-scale habitats. Four data collection methods were utilised generating 33,058 adult or larval invertebrates. The sampling methods comprised benthic kick-sampling, sticky trapping, light trapping, and emergence trapping. For the sticky trapping and light trapping, sampling was carried out at three different sites (Sites 1–3) within each location. The sites were situated within three habitat types; native forest, native forest-fringe, and raupo wetland. Emergence trapping also commenced within the three sites, at both locations, but was discontinued after two months, due to the equipment being destroyed by consecutive flooding events (method described in Appendix 1). Benthic sampling was carried out within the Forest and Forest-fringe habitats. Benthic sampling, sticky trapping, and light trapping were carried out following a monthly schedule between June and November 2005. Conductivity, pH, and water temperature measurements were taken concurrently with benthic sampling on a monthly basis, while water velocity and substrate measurements were taken once to assist in habitat characterisation. Overall, 71 taxa were recorded by benthic sampling over the six month period, with a mean of approximately 30 taxa per site per month. In comparison with similar studies elsewhere in New Zealand, a figure of around 30 taxa per sample was high. The benthic macroinvertebrate fauna at all sites was dominated by Trichoptera (19 taxa), Diptera (16 taxa) and Ephemeroptera (10 taxa). This pattern of diversity is similar to that reported in other New Zealand studies. However, in contrast to previous studies, the leptophlebiid mayfly genus Deleatidium was not numerically dominant over the rest of the community, and other leptophlebiid genera (Acanthophlebia, Atalophlebioides, Mauiulus and Zephlebia) were equally represented, possibly reflecting niche partitioning between the groups. The genus Nesameletus was not recorded at any site, despite being one of the core mayfly species in New Zealand streams. The rare mayfly Isothraulus abditus was recorded at one of the forest locations. There are no published records of this species from Northland. Although acknowledged as another of the core New Zealand benthic taxa, the hydropsychid caddisfly Aoteapsyche was not recorded during the study. However, another hydropsychid, Orthopsyche, was commonly recorded, and these may be filling a similar niche to the Aoteapsyche genus. In contrast to the Trichoptera, Diptera, and Ephemeroptera, the Plecoptera fauna was relatively depauperate, probably reflecting the warmer climate of the region and lack of temperature-buffered spring-fed streams. Surprisingly, Zelandobius, a core New Zealand genus, was absent but is regularly recorded in Northland. A species of conservation interest, Spaniocercoides watti, currently recognised as a Northland endemic, was recorded in low numbers. There were no apparent trends in diversity or abundance of benthic invertebrates over time. Also, there were no significant differences in species diversity between the two locations. However, in many cases, taxa were more abundant at Location 2. This may have been due to steeper gradients at Location 2, and the consequent effects on substrate size and streambed stability, as all other physical factors appeared similar between locations. Although several significant differences of individual benthic taxa were recorded, no broad effect of habitat (sites) on species diversity was observable. However, at Location 2, abundances were significantly higher at Site 3 (Forest) compared to Site 2 (Forest-fringe). The reasons were uncertain, but may be attributed to higher retention of allochthonous organic materials, trapped by in-stream cover and larger substrates. Investigations of adult stages by sticky traps supported benthic results recording community compositions and abundances dominated by Trichoptera and Diptera. Plecoptera were poorly represented. Location 2 recorded higher abundances of taxa, particularly Ephemeroptera and Plecoptera. Investigations of adult stages by light traps however did not produce any statistically significant differences in abundances between sites, between locations, or between sites across locations, and it is believed to be due to limited sampling replication combined with some biases of light trapping. This study indicates that the aquatic invertebrate community at Matapouri is diverse but also reasonably representative. Several rare or uncommon insects inhabit the catchment. It is therefore important that Iwi and the local Landcare Group, who invited and supported this research, together with the Department of Conservation, continue their efforts in protecting these areas. The resident fauna have the capacity to restock areas downstream, which are intended to be improved and restored through sediment control and riparian management.

The potential relationship between riparian arachnids and aquatic insect productivity was assessed in forest streams throughout the central South Island of New Zealand. Initially, a survey was conducted of thirty seven, first-third order forest streams. Streams were selected to represent a range of benthic invertebrate standing crops (as a surrogate measure of "productivity") from Banks Peninsula streams with relatively high benthic invertebrate densities to acid mine drainage streams near Reefton that were almost devoid of aquatic life. At each site benthic invertebrate densities and biomass were measured in riffle habitats and adjacent gravel bars were sampled for terrestrial invertebrates. At a sub-set of 16 sites, a 20 metre longitudinal web-building spider survey was conducted along each bank of the stream. As an additional component, a 20 metre transect starting at the stream margin and running perpendicularly into the forest was used to survey the density of web-building spiders with increasing distance from the stream. Results from the survey of in-situ stream insect biomass and gravel bar invertebrates showed a strong relationship between aquatic insect biomass and the biomass of riparian arachnids (R2 = 0.42, P < 0.001) having accounted for potentially confounding factors such as stream size, elevation, substrate and disturbance. The 20 metre longitudinal survey showed that streams with the highest in-situ insect biomass had significantly higher densities of web-building spiders along their banks (R2 = 0.28, P < 0.05), having accounted for potential confounding variables of elevation, habitat architecture and stream and channel width. The stream to forest survey showed a strong exponential decay in web-building spider densities with increasing distance from the stream (R2 = 0.96, P < 0.0001). Regardless of stream productivity web-building spiders were most abundant at the stream margins and rapidly declined to very low densities 20 metres from the stream. In order to further test the relationship between riparian web-building spider densities and stream insect productivity, a stream fertilization experiment was conducted on six first-second order streams in the Maimai experimental catchment, Reefton. Three streams were enriched by the addition of a fertiliser solution mainly consisting of sodium nitrate for seven months, and the other three streams were used as controls. Water chemistry, benthic invertebrate communities, emerging aquatic adults, and the densities of web-building spiders along the stream corridor and in the forest were monitored in three seasons (spring, summer and autumn) over the course of the nutrient-addition. By the end of the experiment, conductivity was significantly higher in nutrient-addition streams than in the control streams (F = 80.5, P < 0.001), but chlorophyll concentrations showed no significant differences between treatments. Both benthic mayfly densities (F = 6.15, P < 0.05) and the biomass of adult aquatic dipterans (Chironomidae, Simuliidae) (F = 9.25, P < 0.01) were significantly higher in nutrient-addition streams in the last sampling round. Spiders recorded from intercept traps indicated that by the end of the experiment spider activity was significantly higher within 2.5 metres of the nutrient-addition streams (F = 5.70, P < 0.01). However, seasonal densities of web-building spiders along the stream margin and in the forest decreased with no significant differences observed between nutrient-addition and control streams. The results from these studies indicate that adult insects emerging from streams represent an important source of prey that could influence the biomass and abundance of riparian arachnids. Additionally, the results imply that stream productivity and size could mediate the strength of the interaction between riparian and stream habitats. Moreover, feedback mechanisms present in both systems could have implications for such interactions. The elevated densities of web-building spiders observed at the stream margin led to the proposal of the "Highway Robber" hypothesis. This hypothesis suggests that such higher densities of spiders are the result of increased insect activity along the stream corridor: the emergence of adult aquatic insects was predicted to vary less over temporal and spatial scales than that of terrestrial insects due to the poorly synchronized life histories in many New Zealand stream insects. I conclude by suggesting that there are numerous anthropocentric perturbations such as loss of heterogeneity, introduced species, pollution and habitat degradation that could undermine and decouple the intimate linkages between aquatic and terrestrial ecosystems.

Orientador: Virginia Sanches Uieda / Resumo: Macroinvertebrados bentônicos são comumente utilizados como bioindicadores da qualidade do habitat em riachos. Estes estudos podem ser realizados através de uma abordagem taxonômica ou funcional da comunidade. Na abordagem funcional, a classificação em grupos funcionais de alimentação (FFG - Functional Feeding Groups) baseia-se nos mecanismos de apreensão do alimento e nos recursos consumidos. O estudo teve o objetivo de verificar o efeito de alterações na mata ripária sobre a estrutura dos FFG em comunidades de macroinvertebrados bentônicos. Estudamos 36 riachos, separados em três tipos de entorno: com mata ripária nas duas margens (florestado), com mata em uma das margens e pastagem na outra (intermediário) e sem mata nas duas margens (pastagem). A análise das variáveis ambientais indicou uma diferenciação dos riachos florestados e da maioria dos intermediários devido a maiores valores de material alóctone e oxigênio dissolvido e menores de vegetação nas margens e substrato fino, quando comparados aos de pastagem. A análise da abundância da fauna em cada FFG indicou uma diferença entre entornos somente para coletores, com valores significativamente menores nos florestados quando comparados aos de pastagem e intermediários. Já a análise aplicada aos dados de presença-ausência mostrou diferença entre entornos somente para os predadores, indicando diferença significativa na composição entre riachos florestados e de pastagem. A análise da diferenciação dos entornos considerando... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Benthic macroinvertebrates are commonly used as bioindicators of the habitat quality in streams. These studies may be carried out through analyzes with taxonomic or functional approach of the assemblage. In the functional approach, the classification of macroinvertebrates into Functional Feeding Groups (FFG) is based on the mechanisms of food´s apprehension and the resources consumed. This study aimed to verify the effect of the changes in riparian forest upon the structure of FFG in assemblages of benthic macroinvertebrates. We studied 36 streams, separated in three types of land use: with riparian forest on both banks (forest), with forest on one of the banks and pasture on another (intermediate) and without forest on both banks (pasture). The analysis of environmental variables showed a differentiation of the forest and most of the intermediate streams due to high values of allochthonous material and dissolved oxygen and low amounts of vegetation on the banks and unconsolidated substrate, when compared to pasture streams. The analysis of the abundance of the fauna in each FFG indicated a difference between types of land use only for gathering collectors, with significantly low abundance in forested streams when compared to pasture and intermediate ones. On the other hand, analysis applied to the presence-absence data showed distinction between land uses only for predators, indicating significant difference in the composition of forest and pasture streams. The analysis of t... (Complete abstract click electronic access below) / Mestre

I first review the significance of dispersal for individuals and populations including the role of the most significant environmental drivers on separate phases of dispersal. Emphasis is put on aquatic insects inhabiting small standing waters. The following manuscript summarizes a quantitative study of diel and seasonal flight patterns of adult Chironomidae in the Cep II sandpit in southern Bohemia. It provides one of the first comprehensive treatments of the effect of weather conditions and seasonality on the flight activity of adult Chironomidae, phenology of most common species and differences between terrestrial and aquatic species.

Climate changes affect species interactions which can have cascading effect up to the ecosystem level. This work investigates the effects of temperature and predator size on predator prey interactions by measuring the feeding rates of predators and metabolic rates of both predator and prey, using dragonfly larvae Aeshna cyanea and toad tadpoles Bufo bufo as a model system. Possible consequences of the findings for the impacts of climate change and predation on amphibian populations are discussed.

Made available in DSpace on 2016-06-02T19:31:35Z (GMT). No. of bitstreams: 1 1022.pdf: 831752 bytes, checksum: 9e56fcd2ddeaa8d758e2e0c8baab175a (MD5) Previous issue date: 2006-04-28 / Universidade Federal de Sao Carlos / In this study we investigated the temporal dynamics of a chironomid assemblage in a forested stream located in southeastern Brazil. First, we analyzed some diversity patterns of this assemblage by describing two macroecological relationships (body size-species richness and body size-abundance) and by testing with they vary in an intra-annual scale. Second, we analyzed the emergence phenology using a time series of 48 weekly samples. In general, both species richness and abundance peaked on intermediate body sizes, moreover these relationships showed to be variable in this intra-annual scale; Chironomidae emergence was not seasonal, neither was related to any environmental variables measured; on the other hand, the most persistent species (Caladomyia sp. 1, Endotribelos sp. 4, Caladomyia sp. 2, and Corynoneura sp. 1) appeared to have some temporal structure on emergence, probably associated with photoperiod and minimum air temperature respectively; there was no synchrony in species emergence with most taxa emerging together through the year; species richness as taxonomic composition did not change over time. / Neste estudo nós investigamos a dinâmica temporal de Chironomidae em um córrego florestado localizado no sudeste do Brasil. Primeiro, nós analisamos alguns padrões de diversidade através da descrição de duas relações macroecológicas (tamanho do corpo-riqueza de espécies e tamanho do corpo-abundância) e também testamos se essas relações variavam na escala intra-anual. Segundo, nós analisamos a fenologia da emergência usando uma série temporal de 48 coletas semanais. De maneira geral, ambas a riqueza de espécies e a abundância apresentaram um pico nos tamanhos intermediários, além disso, estas relações mostraram ser variáveis nesta escala intra-anual; a emergência de Chironomidae não foi estacional, e também não foi relacionada a nenhuma variável ambiental medida; por outro lado, as espécies mais persistentes (Caladomyia sp. 1, Endotribelos sp. 4, Caladomyia sp. 2, e Corynoneura sp. 1) parecem apresentar alguma estrutura temporal na emergência, provavelmente relacionada ao fotoperíodo e a temperatura mínima do ar respectivamente; não houve sincronia na emergência das espécies, com a maioria dos taxa emergindo juntos ao longo do ano; a riqueza de espécies assim como a composição taxonômica não mudaram ao longo do tempo.

Made available in DSpace on 2016-06-02T19:31:42Z (GMT). No. of bitstreams: 1 2349.pdf: 1899806 bytes, checksum: 1ca8f320416d8d48b697158213960e69 (MD5) Previous issue date: 2009-03-05 / Universidade Federal de Sao Carlos / The aim this work was study species Labrundinia Fittkau, 1962 (Diptera: Chironomidae: Tanypodinae: Pentaneurini) at São Paulo State. This taxon is commonly cited in ecological studies, always in generic level. In the Neotropical region are known 10 species, however none specifically mentioned for Brazil. The sampling followed the conventional methods of benthonic studies. In laboratory the larvae were kept alive to obtain the three development phases: larva, pupa and adult. The results allowed the identification of five species*, four of which are new species and the first record of Labrundinia tenata Roback (1987) for Brazil. The species are described with their respective diagnoses. Information about species natural history of genus is presented and propels for the identification keys, for the different stages of life, are given. / O objetivo deste trabalho foi estudar espécies de Labrundinia Fittkau, 1962 (Diptera: Chironomidae: Tanypodinae: Pentaneurini) no Estado de São Paulo. Esse táxon é comumente citado em muitos trabalhos de cunho ecológico, sempre em nível genérico. Na região Neotropical são conhecidas 10 espécies, porém nenhuma especificamente mencionada para o Brasil. As coletas em campo seguiram a metodologia convencional para estudos bentônicos. Em laboratório as larvas foram mantidas vivas para a obtenção das três fases de desenvolvimento: larva, pupa e adulto. Os resultados permitiram a identificação de cinco espécies*, das quais quatro são espécies novas para a ciência e o primeiro registro de Labrundinia tenata Roback (1987) para o Brasil. As espécies são descritas com as respectivas diagnoses. Informações sobre a história natural das espécies do gênero são apresentadas e propostas de chaves de identificação, para os diferentes estágios de vida, são dadas.