Runnelling is a popular method of physical habitat modification employed on saltmarshes to control pest mosquito populations. The runnelling method involves linking the tidal source to isolated mosquito breeding pools via shallow channels that enable slow water movement of low amplitude tides. Increased tidal flushing inhibits mosquito development. The range of organisms which inhabit saltmarsh are likely to be influenced by altered tidal conditions as they exhibit specific physicochemical requirements for feeding, burrowing or growth. The dynamic nature of saltmarsh may mean that changes to the tidal frequency of a particular region of the saltmarsh promotes extension of marine-like conditions. Because runnels increase the frequency of flooding tidal events in specific regions of the saltmarsh this study predicted that resulting changes would be evident in the physical conditions of saltmarsh substrate, in the transport of buoyant vegetative propagules, in the population characteristics of surface grazing snails and in the density and aperture of crab burrows after flooding and non-flooding tidal events. The physical impacts of runnelling were determined at three marshes which appeared similar in terms of topography, substrate and tidal conditions. Soil water content and consolidation were measured using two sampling protocols: a) comparisons between modified and unmodified shores; and, b) comparisons with increasing lateral distance across the shore from the runnel edge. At one marsh, moisture levels were significantly higher at runnelled than at unrunnelled sites when tides filled the runnels, but this pattern was not found at the other marshes. Soil consolidation was greater at higher shore heights, but was not different between runnelled and unrunnelled shores. Measurements at different lateral distances from runnels demonstrated higher moisture levels and lower consolidation up to 5 m from the edge but not further away. Groups of marked Avicennia marina propagules were released at the three runnelled saltmarshes during flooding and non-flooding tidal events. Groups of propagules released within 10 m of a runnel were always transported significantly further from the starting position and further up the saltmarsh shore after both flooding and non-flooding tides than any other groups. In addition, the pattern of stranding on saltmarsh for significantly different groups was closely associated with the path of runnel construction so that propagules were located either in the runnel or in depressions linked to the runnel that had been isolated mosquito-breeding pools prior to runnelling. It is likely that altered physical soil conditions significantly affected the distribution and size structures of Salinator solida and Ophicardelus spp. snails recorded at the three saltmarshes. The interaction of tidal period and the presence of a runnel contributed to patterns with significant differences between runnelled and unrunnelled regions of the marsh. Generally, the runnel population of snails exhibited flood-like features even during non-flood periods. The distribution and size classes of snails did not differ with lateral distance from runnels. The burrow characteristics of the crab Helograpsus haswellianus were compared to increase the accuracy of estimating abundance from burrow counts. Including only those burrows which were obviously maintained by resident crabs significantly increased the confidence limits of estimating crab abundance using only burrow density counts. This method was applied to runnelled and unrunnelled sites to assess any changes in the density of burrows associated with the presence of runnels. Again, it is likely that physical soil conditions resulting from increased tidal frequency at the runnel did influence crab burrowing with fewer small burrows being found at the runnelled site, low on the shore. In addition, mid- and large-sized burrows tended to dominate close to the runnel edge. Site-specific soil characteristics may help to explain the lack of continuity in patterns associated with runnel effects on non-target saltmarsh resources. While the runnel may increase the soil water content of clayey substrates at some sites it could also result in de-watering of porous sandy soils at other shores. This was evident in the structure of the snail population and distribution of crab burrows which appeared to reflect altered soil physical characteristics associated with the runnel. Runnelling does affect non-target organisms in saltmarsh. However, the scale of impact was usually locally restricted (< 10 m from the runnel edge). The fact that patterns were not recorded at all sites suggests that the influence of runnels is variable and limited by substrate and some biological conditions. Given the efficiency and popularity of runnelling as a physical control method for reducing pest vector mosquito habitat, this study found no evidence to suggest that its use should be discontinued on any ecological basis measured.

Rich fens are calcareous and nutrient poor wetlands with a rich flora of orchids, sedges and mosses. As many as one hundred plant species are rich fen specialists. Many wetlands have been drained historically, and transformed to agricultural land or production forests. Today rich fens cover only 2-3% of the total mire area in Sweden. Rich fen is a rare and valuable habitat also from a European perspective and is protected in the Natura 2000-network. To increase and maintain the biodiversity and ecosystem services rich fens can offer, it is important to increase the rich fen area by restoration and management. Rich fen restoration can be carried out in different ways. In this report the restoration method of top soil removal is investigated. The method has never been tested before in Sweden and therefore it is important to evaluate the suitability of the method for further conservation work.   Before restoration, the study area had been drained, used as arable land and pasture, and finally become abandoned and overgrown by tall eutrophic herbaceous vegetation. An excavator dug away the layer of nutrient rich top soil and then the site was left for spontaneous development. Adjacent to the restored area, there is a small remnant of rich fen. Monitoring of the restored area was performed during the first five years after the restoration. I repeated the monitoring after ten years, and analyzed the long-term succession of plants and snails, in comparison with the status in the reference fen.   The vegetation in the restored parts is approaching the one in the reference fen. For example, the number of rich fen specialists has increased steadily. However, the colonization of bryophytes is slow. They cover at most 20 % in the restored parts, while 80 % in the reference fen, possibly because of dispersal limitation and the fact that the restored area is drier than the reference fen. More species of herbs can be found in the restored parts than in the reference fen. Another difference is the high cover of bare soil in the restored areas, compared to none in the reference fen. Some trees and bushes are growing in the area, primarily birch (Betula pubescens) and different species of Salix. The land snails have successfully colonized the restored areas. After two years the same number of species was found in the restored area, as in the reference fen. The total number of species found in the restored areas was 26, compared to 29 in the reference fen, among them three rare rich fen indicator species.   The results show how the restored site has developed from bare mineral soil to a rich fen site, approaching the species composition of the reference fen. Several species of rich fen specialists among vascular plants, bryophytes and land snails have established in the restored areas. The small rich fen close to the restored area functions as a source from where plants and animals can spread. Overall the restoration shows very positive results, going from bare soil to rich fen vegetation in only ten years.

Predatory shallow-water tropical marine snails within the genus Conus are estimated to consist of up to 700 species. These carnivorous mollusks have devised efficient venom harpoon-like radular teeth that allow them to predominantly incapacitate polychaete annelids (vermivores), in some cases fish (piscivores), or other mollusks (molluscivores) as an envenomation survival strategy for feeding, defense, and competitor deterrence. The venom of each Conus species contains a distinctive assortment of over 50 diversified disulfide-rich conotoxins with varied pharmacological specificities that selectively inhibit the function of ion channels (Ca2+, Na+, K+) or nicotinic acetylcholine receptors (nAChRs) involved in the animal neurotransmission. Across the genus Conus, the conotoxins represent an extensive array of ion channel blockers each showing an exquisite selectivity to distinguish between channels / receptors and even particular their subtypes. Novel conotoxins detected in the molecular neurobiological approach, providing chemists and pharmacologists a vast library (>50,000 individual toxins) of conotoxins have been further screened for their abilities to modify the responses of tissues to pain stimuli as a first step in describing their potential as lead compounds for novel drugs. In this article, we present the natural history of the Conus biology as well as the nomenclature, classification, structure, neurotoxicological mechanisms, post-translational modification, and pharmaceutical applications of conotoxins. In addition, we also set up the bioinformatic database and search engine about hitherto-identified name and distribution of Conus species and neuropharmacological mechanism, accession number, sequence, and 3D structure of conotoxins and provide researchers advantageous tools for further investigation.

Thesis (Ph.D.)--Mississippi State University. in Veterinary Medical Sciences in the Department of Basic Sciences. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--University OF MICHIGAN.

DISSERTATION (PH.D.)--THE UNIVERSITY OF MICHIGAN

Digenetic trematodes are a common pest problem in aquaculture where their unappetizing appearance often reduces the marketability of food fish. Aquatic snails are intermediate hosts in the trematode lifecycle and are commonly targeted with control measures to prevent the crop fish from becoming infected. I evaluated several chemical and biological snail control strategies as alternatives to the potentially invasive black carp. Copper sulfate, hydrated lime slurry, and several fish and decapod species were tested for effectiveness against physid (Physa spp.) and planorbid (Helisoma spp.) snails in laboratory aquaria trials. Hydrated lime demonstrated effectiveness with the least potential to be toxic to cultured fish in regional application. Hybrid sunfish (redear × green sunfish) consumed large quantities of both snails in ad libitum feedings. The most effective biological (redear × green sunfish) and chemical (hydrated lime) control methods identified in the laboratory were evaluated further in research ponds. Hydrated lime applications of 9.07 kg over 9.14 m2 were found to be effective against Helisoma spp. confined to enclosures along the pond shoreline; average survival was 2%. When stocked in aquaculture ponds, hybrid redear sunfish did not significantly influence snail capture rates; however ponds stocked with redear sunfish experienced a gradual decrease in snail populations throughout the 2008 growing season. Hydrated lime and a combination of redear sunfish and hybrid redear sunfish were evaluated separately and in tandem as a combined chemical/biological treatment in the 2009 growing season. Evaluation occurred under mock production conditions in which hybrid striped bass were raised in the research ponds to determine snail treatment effects on trematode abundance. Ponds stocked with sunfish at 494 fish/ha had snail densities significantly (P ≤ 0.05) lower than control ponds after two months. Ponds treated with hydrated lime at 31.7 kg/31.5 m of shoreline in a 1 m swath experienced 99% estimated reductions in snail densities following application, but snail populations rebounded to previous levels within two months. The mean snail density in ponds treated with both hydrated lime and sunfish was significantly lower than control one month post treatment; this mean rebounded slightly by the conclusion of the trial, but not as much as in the chemical treatment group. Hybrid striped bass examined thoroughly for trematodes revealed a positive relationship between trematode abundance in fish and increasing Helisoma densities. This relationship was most apparent when estimates of snail density from only the beginning of the trial were used. Based on these results, it appears that a nearly complete reduction of Helisoma, particularly at the time of stocking fingerlings, is necessary to avoid a high abundance of trematodes in cultured fish. To this end, an early-season application of molluscicides followed closely by stocking of predator sunfish has potential to achieve a uniformly low density of snails throughout the growing season.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 55-58). / Ceratostoma ioornatum is an introduced marine snail in Puget Sound, Washington. Two of five native species tested as possible predators ate Ceratostoma. These two species, the crabs Cancer gracilis and Lopbppaoopeys bellys, did not eat native snails similar to Ceratpstpma, but ate native and introduced bivalves more than Ceratpstpma. The reasons for the differences in predation seemed to be explained by shell strength of the prey species. The presence of Ceratpstpma adds a new type of prey to the menu of the two crab species at the sites studied.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O comportamento espacial dos indivíduos é um componente chave para se entender a dinâmica de população dos organismos e esclarecer o potencial de migração e dispersão das espécies. Vários fatores afetam a atividade de locomoção de moluscos terrestres, como temperatura, luz, umidade, época do ano, tamanho da concha, sexo, estratégia reprodutiva, idade, densidade de coespecíficos e disponibilidade de alimento. Um dos métodos usados para estudar deslocamento de gastrópodes terrestres é o de marcação-recaptura. Gastrópodes terrestres se prestam a este tipo de estudo por causa de (1) seu reduzido tamanho, (2) fácil manejo, (3) fácil captura e (4) pequenas distâncias de deslocamento e, consequentemente, reduzidas áreas de vida. Estes organismos servem como modelo para o estudo de ecologia espacial e dispersão. Estudos de população, investigando o uso do espaço, a distribuição espacial, a densidade populacional e a área de vida são escassos para moluscos terrestres e ainda mais raros em áreas naturais tropicais. Nosso objeto de estudo é Hypselartemon contusulus (Férussac, 1827), um molusco terrestre carnívoro, da família Streptaxidae, muito abundante na serrapilheira, em trechos planos de mata secundária na Trilha da Parnaioca, Ilha Grande, Rio de Janeiro. A espécie é endêmica para o estado do Rio de Janeiro. Seu tamanho é de até 7,2 mm de altura, apresentando 6 a 7 voltas. Neste trabalho estudamos as variáveis temperatura ambiente, temperatura do solo, umidade do ar, luminosidade, profundidade do folhiço, tamanho do animal, densidade de co-específicos e densidade de presas, relacionando estes dados ecológicos ao deslocamento observado em Hypselartemon contusulus. Uma das hipóteses de trabalho é que estas variáveis afetam seu deslocamento. O trabalho foi realizado na Ilha Grande, situada ao sul do Estado do Rio de Janeiro, no município de Angra dos Reis. Os animais foram capturados e marcados com um código individual pintado na concha com corretor ortográfico líquido e caneta nanquim. As distâncias de deslocamento, em cm, foram registradas medindo-se as distâncias entre marcadores subsequentes. Os resultados encontrados indicam que o método utilizado é eficaz para marcar individualmente Hypselartemon contusulus em estudos de médio prazo (até nove meses). Sugerimos o uso deste método de marcação para estudos com gastrópodes terrestres ameaçados de extinção, como algumas espécies das famílias Bulimulidae, Megalobulimidae, Streptaxidae e Strophocheilidae. Hypselartemon contusulus não mantém uma distância mínima de seus vizinhos, é ativo ao longo de todo o ano e ao longo do dia, demonstrando atividade de locomoção e predação. Não foram encontrados animais abrigados sob pedra ou madeira morta. Não foram observados locais de atividade em oposição a lugares de repouso/abrigo. Beckianum beckianum (Pfeiffer, 1846) foi a presa preferencial. A densidade populacional variou de 0,57 a 1,2 indivíduos/m2 entre as campanhas de coleta. A espécie desloca-se, em média, 26,57 17,07 cm/24h, na Trilha da Parnaioca, Ilha Grande. A área de vida de H. contusulus é pequena, sendo de, no máximo, 0,48 m2 em três dias e 3,64 m2 em 79 dias. O deslocamento da espécie variou ao longo do ano, mas esta variação não é afetada pelas variáveis ecológicas estudadas. Este é, portanto, um comportamento plástico em H. contusulus e, provavelmente, controlado por fatores endógenos. / Spatial behavior of individuals is a key component to understanding and clarify migration and dispersion potential of species. Many factors affect locomotory activity of land mollusks, like temperature, light, humidity, period of the year, shell size, sex, reproductive strategy, age, co-specific density and food quantity. The mark-recapture method is used to study displacement of land snails. Land snails lend themselves to this kind of study because of their small size, easy handling, easy capture and small displacement distances and, consequently, small home ranges. These organisms serve as model to study spatial ecology and dispersion. Studies on population, concerning spatial behavior and distribution, population density and home range are rare for land snails and even rariest in natural tropical areas. Our study object is Hypselartemon contusulus (Férussac, 1827), a carnivorous land snail, family Streptaxidae, very common in leaf litter, in plane parts of secondary forest in the Trail of the Parnaioca, Ilha Grande, Rio de Janeiro. The species is endemic to Rio de Janeiro state. His size is 7.2 mm height, in maximum, showing six to seven whorls. In this work, we studied the environment variables temperature, soil temperature, air humidity, luminosity, leaf litter depth, shell size, co-specific density and prey density, connecting these ecologic data to the displacement observed to H. contusulus. The research hypothesis is that these variables affect its displacement. The work was carried out in Ilha Grande, south of the state of Rio de Janeiro, in the Angra dos Reis municipality. The animals were captured and marked with an individual code painted in the shell with orthographic liquid corrector and nankeen ink. The displacement distances, in cm, were recorded measuring the distances between subsequent markers. The results indicate that the used method is effective to mark individually H. contusulus in intermediate-term studies (until nine months). We suggest the use of this mark method to studies about land threatened land snailst, like some species of the families Bulimulidae, Megalobulimidae, Streptaxidae and Strophocheilidae. Hypselartemon contusulus does not maintain a minimum distance from its neighbours. The species is active during all the day and all year, showing locomotory activity and predation. Animals were not found sheltered under rock or dead wood. Sites of activity in opposition of sites of resting were not observed. Beckianum beckianum (Pfeiffer, 1846) was the preferential prey. Population density varied from 0.57 to 1.2 individuals/m2 between sampling episodes. The species move, in media, 26.57 17.07 cm/24h, in the Trail of the Parnaioca, Ilha Grande. Home range of H. contusulus is small and does not exceed 0.48 m2, in three days and 3.64 m2 in 79 days. Displacement varied during the year, but this variation is not affected by the ecological variables. This is a plastic behavior in H. contusulus and, probably, controlled by endogenous factors.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O comportamento espacial dos indivíduos é um componente chave para se entender a dinâmica de população dos organismos e esclarecer o potencial de migração e dispersão das espécies. Vários fatores afetam a atividade de locomoção de moluscos terrestres, como temperatura, luz, umidade, época do ano, tamanho da concha, sexo, estratégia reprodutiva, idade, densidade de coespecíficos e disponibilidade de alimento. Um dos métodos usados para estudar deslocamento de gastrópodes terrestres é o de marcação-recaptura. Gastrópodes terrestres se prestam a este tipo de estudo por causa de (1) seu reduzido tamanho, (2) fácil manejo, (3) fácil captura e (4) pequenas distâncias de deslocamento e, consequentemente, reduzidas áreas de vida. Estes organismos servem como modelo para o estudo de ecologia espacial e dispersão. Estudos de população, investigando o uso do espaço, a distribuição espacial, a densidade populacional e a área de vida são escassos para moluscos terrestres e ainda mais raros em áreas naturais tropicais. Nosso objeto de estudo é Hypselartemon contusulus (Férussac, 1827), um molusco terrestre carnívoro, da família Streptaxidae, muito abundante na serrapilheira, em trechos planos de mata secundária na Trilha da Parnaioca, Ilha Grande, Rio de Janeiro. A espécie é endêmica para o estado do Rio de Janeiro. Seu tamanho é de até 7,2 mm de altura, apresentando 6 a 7 voltas. Neste trabalho estudamos as variáveis temperatura ambiente, temperatura do solo, umidade do ar, luminosidade, profundidade do folhiço, tamanho do animal, densidade de co-específicos e densidade de presas, relacionando estes dados ecológicos ao deslocamento observado em Hypselartemon contusulus. Uma das hipóteses de trabalho é que estas variáveis afetam seu deslocamento. O trabalho foi realizado na Ilha Grande, situada ao sul do Estado do Rio de Janeiro, no município de Angra dos Reis. Os animais foram capturados e marcados com um código individual pintado na concha com corretor ortográfico líquido e caneta nanquim. As distâncias de deslocamento, em cm, foram registradas medindo-se as distâncias entre marcadores subsequentes. Os resultados encontrados indicam que o método utilizado é eficaz para marcar individualmente Hypselartemon contusulus em estudos de médio prazo (até nove meses). Sugerimos o uso deste método de marcação para estudos com gastrópodes terrestres ameaçados de extinção, como algumas espécies das famílias Bulimulidae, Megalobulimidae, Streptaxidae e Strophocheilidae. Hypselartemon contusulus não mantém uma distância mínima de seus vizinhos, é ativo ao longo de todo o ano e ao longo do dia, demonstrando atividade de locomoção e predação. Não foram encontrados animais abrigados sob pedra ou madeira morta. Não foram observados locais de atividade em oposição a lugares de repouso/abrigo. Beckianum beckianum (Pfeiffer, 1846) foi a presa preferencial. A densidade populacional variou de 0,57 a 1,2 indivíduos/m2 entre as campanhas de coleta. A espécie desloca-se, em média, 26,57 17,07 cm/24h, na Trilha da Parnaioca, Ilha Grande. A área de vida de H. contusulus é pequena, sendo de, no máximo, 0,48 m2 em três dias e 3,64 m2 em 79 dias. O deslocamento da espécie variou ao longo do ano, mas esta variação não é afetada pelas variáveis ecológicas estudadas. Este é, portanto, um comportamento plástico em H. contusulus e, provavelmente, controlado por fatores endógenos. / Spatial behavior of individuals is a key component to understanding and clarify migration and dispersion potential of species. Many factors affect locomotory activity of land mollusks, like temperature, light, humidity, period of the year, shell size, sex, reproductive strategy, age, co-specific density and food quantity. The mark-recapture method is used to study displacement of land snails. Land snails lend themselves to this kind of study because of their small size, easy handling, easy capture and small displacement distances and, consequently, small home ranges. These organisms serve as model to study spatial ecology and dispersion. Studies on population, concerning spatial behavior and distribution, population density and home range are rare for land snails and even rariest in natural tropical areas. Our study object is Hypselartemon contusulus (Férussac, 1827), a carnivorous land snail, family Streptaxidae, very common in leaf litter, in plane parts of secondary forest in the Trail of the Parnaioca, Ilha Grande, Rio de Janeiro. The species is endemic to Rio de Janeiro state. His size is 7.2 mm height, in maximum, showing six to seven whorls. In this work, we studied the environment variables temperature, soil temperature, air humidity, luminosity, leaf litter depth, shell size, co-specific density and prey density, connecting these ecologic data to the displacement observed to H. contusulus. The research hypothesis is that these variables affect its displacement. The work was carried out in Ilha Grande, south of the state of Rio de Janeiro, in the Angra dos Reis municipality. The animals were captured and marked with an individual code painted in the shell with orthographic liquid corrector and nankeen ink. The displacement distances, in cm, were recorded measuring the distances between subsequent markers. The results indicate that the used method is effective to mark individually H. contusulus in intermediate-term studies (until nine months). We suggest the use of this mark method to studies about land threatened land snailst, like some species of the families Bulimulidae, Megalobulimidae, Streptaxidae and Strophocheilidae. Hypselartemon contusulus does not maintain a minimum distance from its neighbours. The species is active during all the day and all year, showing locomotory activity and predation. Animals were not found sheltered under rock or dead wood. Sites of activity in opposition of sites of resting were not observed. Beckianum beckianum (Pfeiffer, 1846) was the preferential prey. Population density varied from 0.57 to 1.2 individuals/m2 between sampling episodes. The species move, in media, 26.57 17.07 cm/24h, in the Trail of the Parnaioca, Ilha Grande. Home range of H. contusulus is small and does not exceed 0.48 m2, in three days and 3.64 m2 in 79 days. Displacement varied during the year, but this variation is not affected by the ecological variables. This is a plastic behavior in H. contusulus and, probably, controlled by endogenous factors.