Benthic invertebrates play important roles as feeding resources for many organisms in different food webs. Shifts in predation of these organisms can generate cascading effects and potentially lead to the disappearance of one or more species from a site. Cascading effects can bring impacts to organisms who aren’t even directly involved, why studies in this field are important for understanding sudden changes in ecosystems. I examined the predation from fish and waterfowl on benthic invertebrates in the shallow and eutrophic Lake Tåkern in the plains of Östergötland County, southern Sweden. The study was experimental and used exclosures (three types, eight replicates) in the shape of 130-liter cages to examine the composition of invertebrates. It was conducted during early spring, a relatively unexamined period for this kind of study. I found no significant differences in the control treatment compared to any of the other treatments regarding biodiversity. The invertebrate fauna was dominated by a small number of species, with a relatively patchy spread throughout the sediment area. Furthermore, the results indicate that the fish hadn’t had the time to properly activate their predatory habits due to prolonged winter temperatures. The waterfowl were considered too absent during the test period to affect the invertebrate community. Future studies in this area are recommended to work with a greater sampling area, to reduce the influence of extreme values.

Each year thousands of western waterfowl succumb to disease, predators, mechanical injury and other decimating factors. Based on a review of records it is conservatively estimated that an average of 25,000 ducks have succumbed to botulism on western marsh areas annually. In a recent study, the United States Fish and Wildlife Services valued each duck and goose at $8.00 (McLeod, 1950). Applying this value to the estimated annual numerical loss, a total of $200,000 has been lost each season in mortality of western waterfowl from botulism. Control of this malady would reduce annual waterfowl and monetary losses. Prevention and cure are the only means of controlling botulism in wild ducks. At present, no economical preventative measure exists and control is based on curing stricken birds. The purpose of this study was to evaluate the cost of treatment and rate of recovery of birds stricken with botulism when treated by selected methods. The 4 treatments selected for evaluation were: (1) hospital inoculation, (2) fresh water, (3) field inoculation, and (4) no treatment or control. Research included a comprehensive evaluation of factors such as age, sex, species, body condition, degrees of affliction, reaction to various amounts of antitoxin, and reaction to selected treatment methods, thought to be pertinent in botulism control. This study was conducted during botulism outbreaks of 1953 and 1954, and was confined to state-owned marshlands of Utah.

Dans une ville de Vilnius, la structure et la division des populations d’oiseaux hivernants étaient faites des recherches en 2003 – 2005. Ainsi que dans les étangs des régions de Neris, Vilnelė et de Žvėrynas. Pendant la période des recherches les neuf espèces d’oiseaux migrateurs étaient aperçues: le canard colvert, le harle bièvre, la mouette rieuse, la poule d’eau, le fuligule milouin, le garrot à œil d’or, le grèbe huppé, le foulque macroule, le cygne muet. Pendant des recherches de différents saison dans toutes les gisements d’eau de Vilnius on rencontre le plus souvent le canard colvert et le harle bièvre. La mouette rieuse était trouvée aussi dans toutes les gisements d’eau, mais l’abondance de la mouette rieuse s’accroîssait seulement pendant la période de la migration d’été. Le plus grandes agglomérations des canards colverts on trouve dans les étangs de Žvėrynas, Vilnelė et à coté de la région d’Antakalnis. Dans ces endroits les canards sont nouris toujours. Des endroits pour hiverner le plus importants pour le harle bièvre sont dans une rivière Neris à coté d’un parc Vingis, à Vilnelė et à Neris à coté de la région d’Antakalnis. Pour appréciér l’abondance des oiseaux en 2003 – 2004 et en 2004 – 2005 pendant des saisons d’hiver l’abondance de la population a changé seulement du harle bièvre: en 2004 – 2005 en hiver la population de cette espèce d’oiseaux était plus petite que en hiver dernièr.

In Canada, regulations against the use of lead (Pb) shot for waterfowl hunting were first established in the early 1990s with the creation of a few non-toxic shot zones, and culminated with a national ban in 1997. Prior to establishment of the first non-toxic shot zones in Canada, a nation-wide survey of Pb accumulation in wing bones of young-of-the-year (YY) dabbling and diving ducks determined the incidence of elevated Pb exposure in different parts of the country (Scheuhammer & Dickson, 1996). The objective of the present study was to determine the incidence of elevated Pb accumulation in the same species several years after the national ban on Pb shot; to survey waterfowl hunters to determine approximate levels of compliance with the Pb shot ban; and to use stable Pb isotope analysis to help determine the relative importance of different sources of Pb exposure. / Wing bones from 721 YY black, mallard, and ring necked ducks, and 579 YY woodcock from selected zones in Ontario, Quebec, BC, and the Maritimes, Canada were analyzed for Pb using flame atomic absorption spectrometry. (Abstract shortened by UMI.)

Submitted by (ana.araujo@ufrpe.br) on 2016-08-23T12:52:01Z No. of bitstreams: 1 Paulo de Barros Passos Filho.pdf: 1494161 bytes, checksum: 0b0d0e131681b763c8f901e59e02eaec (MD5) / Made available in DSpace on 2016-08-23T12:52:02Z (GMT). No. of bitstreams: 1 Paulo de Barros Passos Filho.pdf: 1494161 bytes, checksum: 0b0d0e131681b763c8f901e59e02eaec (MD5) Previous issue date: 2012-08-23 / Brazil has one of the most diverse fauna of birds in the world with 1825 species, which is equivalent to 57% of bird species recorded throughout South America. Among the 160 species that have aquatic habits, the herons and socós) and Anatidae (ducks and teals) are those with greater representation. In the semiarid lakes are important refuges for many species of animals and plants providing increased local diversity. More specific focus on the water birds associating with permanent ponds as well as the importance of these microhabitats for birds diversity in the region has scarcely been addressed. Thus, this research aims to study the variations of wealth, abundance and diversity of waterfowl in relation to the lake ecosystem during periods of flood and ebb in the semiarid permanent lakes; assess the distribution patterns of aquatic species between the hours of the day and know the use of spaces and the main behavior of the species associated with ponds analyzed. We chose two permanent lakes located in Fazenda Tamanduá, municipality of Santa Terezinha-PB. The censuses were conducted in eight days, four for each pond, and monthly over 12 months. Observations were made at five times throughout the day, 5h 30 min, 8 h 30 min, 11 h 30 min, 14 h 30 min and 17 h 30 min. In these times was also evaluated the behavior of birds through continuous naturalistic methods and focal animal. In the lakes studied so registered about 20% of species of aquatic birds in Brazil. A total of 10.939 and 17.176 individuals were recorded for Pond 1 and 2, respectively. The pond had a greater diversity and lower species richness and abundance of the pond 2. In the dry period can be observed a greater richness and abundance for the two ponds. The most abundant species in the lake was a lake Bubulcus ibis and two Dendrocygna viduata. Ordination multidimensional analysis showed dissimilarity between ponds and between the periods studied, these significant results. Amazonetta brasiliensis, Bubulcus ibis, Dendrocygna viduata, Gallinula galeata, Himantopus mexicanus, Jacana jacana, Phalacrocorax brasilianus, Podilymbus podiceps, Tachycineta albiventer, were the species responsible for the dissimilarities among the factors (pond and period). In regard to the times, the lowest abundance was recorded for the time of 11h 30min, which is significantly different from other times. In both lakes most birds are framed as potential residents. The most frequently observed behaviors were resting, and foraging and the area most used by them was the edge of the pond. The piscivores accounted for the majority community. The reproductive behavior occurred in three periods: before, during and after the rainy season. / O Brasil abriga uma das mais diversas avifauna do mundo, com 1825 espécies o que equivale a 57% das espécies das aves registradas em toda a América do Sul. Dentre as 160 espécies que possuem hábitos aquáticos, os Ardeídeos (garças e socós) e Anatídeos (patos e marrecas) são os que apresentam maior representatividade. No semiárido as lagoas são importantes refúgios para muitas espécies de animais e plantas, proporcionando o aumento da diversidade local. Enfoques mais específicos sobre a avifauna aquática associando às lagoas permanentes, bem como, a importância desses micro-hábitats para diversidade de aves na região, praticamente nunca foi abordada, sendo este conhecimento limitado. Sendo assim, esta pesquisa visa estudar a variações de riqueza, abundância e diversidade das aves aquáticas, em relação ao ecossistema lacustre durante os períodos de cheia e vazante em lagoas permanentes do semiárido; avaliar os padrões de distribuição das espécies aquáticas entre os horários do dia e conhecer a utilização dos espaços e os principais comportamentos das espécies associados às lagoas analisadas. Foram escolhidas duas lagoas permanentes situadas na Fazenda Tamanduá, município de Santa Terezinha-PB. Os censos foram realizados em oito dias, quatro para cada lagoa, mensalmente e ao longo de 12 meses. As observações foram feitas em cinco horários ao longo do dia: 5 h 30 min, 8 h 30 min, 11 h 30 min, 14 h 30 min e 17 h 30 min. Nestes horários também foi avaliado o comportamento das aves através dos métodos animal focal e naturalísticos contínuos. Nas lagoas estudadas foram registradas cerca de 20% das espécies de aves aquáticas do Brasil. Um total de 10.939 e 17.176 indivíduos foram contabilizados para a lagoa 1 e 2, respectivamente. A lagoa 1 apresentou maior diversidade e menores riqueza e abundância do que a lagoa 2. No período seco pôde-se observar uma maior riqueza e abundância nas duas lagoas. A espécie mais abundante na lagoa 1 foi Bubulcus ibis e na lagoa 2 Dendrocygna viduata. A análise de ordenação multidimensional constatou a dissimilaridade entre as lagoas e entre os períodos estudados, sendo estes resultados significativos. Amazonetta brasiliensis, Bubulcus ibis, Dendrocygna viduata, Gallinula galeata, Himantopus mexicanus, Jacana jacana, Phalacrocorax brasilianus, Podilymbus podiceps, Tachycineta albiventer, foram as espécies responsáveis pelas dissimilaridades entre os fatores analisados (lagoa e período). Em relação aos horários, a menor abundância foi registrada no horário de 11 h 30 min, sendo este significativamente diferente dos demais horários. Nas duas lagoas a maioria das aves se enquadrou como prováveis residentes. Os comportamentos mais frequentemente observados foram repouso, e forrageio e a área mais utilizada pelas mesmas foi a borda da lagoa. Os piscívoros representaram a maioria na comunidade. O comportamento reprodutivo se deu em três períodos: antes, durante e após o período chuvoso.

Anseriformes mantidos em lagos de zôos e parques estão sob constante risco de exposição às doenças presentes nas populações de aves migratórias, que dividem com eles o mesmo local durante um determinado período todos os anos. São doenças que podem ter implicações para as aves cativas, para a população humana que tem contato com essas aves e para os plantéis de produção. Assim, ações de vigilância, com o objetivo de detectar rapidamente determinadas doenças, representam alternativas interessantes para se fazer gestão de risco. O objetivo do presente estudo foi pesquisar a presença de agentes etiológicos selecionados na população de Cisnes Negros (Cygnus atratus), mantida nos lagos da FPZSP, visto que essa população tem contato com as seguintes aves migrantes que visitam a FPZSP todos os anos: irerês (Dendrocygna viduata), marreca caneleira (Dendrocygna bicolor) e marreca asa de seda (Amazoneta brasiliensis). Assim, foram colhidos suabes de traquéia e cloaca de uma amostra capaz de detectar doença com prevalência estimada em 1% para um nível de confiança de 95%. Além disso, foi realizado um estudo retrospectivo (2001 a 2006) das principais causas de morte nessa população. As principais causas de mortalidade registradas em 184 registros analisados foram: desvio de tendão extensor tarso-metatarsiano (37, 20,1%), desnutrição (20, 10,9%), problemas hepáticos (17, 9,2%), traumas (15, 8,2%), problemas respiratórios (8, 4,3%), septicemias (6, 3,3%), intoxicações (5, 2,7%) e problemas gastrointestinais (3, 1,6%). Um terço das carcaças (62, 33,7%) foi encontrado em estado de putrefação. A taxa de mortalidade foi decrescente de 2001 a 2006 e apresentou sazonalidade, sendo maior entre os meses de novembro a maio. No momento das coletas, não houve nenhuma evidência clínica ou laboratorial da presença dos seguintes agentes: Pasteurella multocida., Salmonella sp., Chlamydophila psittaci, Orthomixovírus (Influenza Aviária), Paramixovirus (Doença de Newcastle) e Coronavirus (Bronquite Infecciosa). / Waterfowls housed in ponds of zoos and parks are under constant risk of exposure to pathogens of migratory birds that visit these places every year. Some of them involving zoo animals and humans. The spread of particular diseases may also become a serious threat for domestic poultry. So, surveillance, focused in early detection of some diseases, can be an interesting tool to do risk management. The goal of the present work was to search the presence of some select pathogens in the captive black swan population (Cygnus atratus) present in the ponds of the Fundação Parque Zoológico de São Paulo (FPZSP), because these animals have contact with the following free-living waterfowls: white-faced whistling-duck (Dendrocygna viduata), fulvous whistling-duck (Dendrocygna bicolor) e brasilian teal (Amazoneta brasiliensis). Swabs of trachea and cloaca were sampled from 239 animals, the sample size required for detecting disease present in at least 1% of the animals (CI = 95%). Moreover, a retrospective study was done about the causes of death to the period from 2001 to 2006. The mainly causes of black swan death in FPZSP were: slipped tendon (37/184, 20,1%), malnutrition (20/184, 10,9%), hepatic problem (17/184, 9,2%), trauma (15/184, 8,2%), respiratory problem (8/184, 4,3%), septicemias (6/184, 3,3%), intoxication (5/184, 2,7%) e gastro-intestinal problems(3/184, 1,6%). One third of the carcass (62/184, 33,7%) was in autolysis. The mortality presented peaks of occurrence from november to may and a decreasing trend from 2001 to 2006. At the moment of the sampling, there was no clinical or laboratorial evidence of the infection by the following pathogens: Pasteurella multocida., Salmonella sp., Chlamydophila psittaci, Orthomixovírus (Avian Influenza), Paramixovirus (Newcastle Disease) e Coronavirus (Infectious Bronchitis).

Muscovy ducks are native only to Central and South America, Mexico, and parts of southern Texas and are considered invasive in some areas outside of their native range. Although they have been introduced worldwide, they remain largely unstudied. The primary focus of this study was to relate Muscovy duck abundance to habitat characteristics of wetlands in Tampa, Florida. Muscovy abundance was measured using point count methods at 21 wetland sites that occur within an eight km radius of the University of South Florida’s main campus. Habitat features at these sites were assessed using field methods and Geographic Information Systems (GIS) (Arc 10.1v). Mann-Whitney U tests and Chi-squared tests were performed to identify significant differences between quantitative data groups. A Chi-squared test determined that there was not a positive correlation between Muscovy abundance and fountains or water regime, yet identified a significant relationship between Muscovy abundance and fencing, in which Muscovies did not frequently occupy ponds with fencing. Mann-Whitney U tests did not identify significances between Muscovy abundance and other habitat groups. Since Muscovy ducks are listed as an invasive species, identifying habitat preferences and deterrents will assist land managers and property owners with habitat modifications in preventing or controlling nuisance Muscovy populations.

The main diet of herbivorous waterfowl, such as swans, coots, and ducks, consists of submerged macrophytes. The grazing by waterfowl below the surface may affect the biomass and species composition of the submerged plants. The vegetations is, however, also affected by e.g. water turbidity, periphyton growing on the plants and water temperature. This literature study aimed to assess the impact of waterfowl on the biomass and production of submerged vegetation in shallow, eutrophic lakes and how this may vary with the season. The review showed that the density of submerged vegetation biomass varies during the seasons but tends to be highest in the summer. Waterfowl density is usually highest during autumn migration. According to experimental field studies in which waterfowl were excluded from protected areas, showed that protected plants had longer shoots and fewer stumps and, in several studies, also higher biomass, than in areas where waterfowl resided free. Although several studies have shown that waterfowl affect the biomass of macrophytes in different ways, is still uncertain to what degree and whether this has a negative or positive impact on the species composition of vegetation in a longer time perspective. However, alternative state shifts in shallow eutrophic lakes from a clear to a turbid water state have not been shown to be caused by waterfowl. With climate change, the time and place of waterfowl migration and wintering will most probably change. This could lead to altered pressure and seasonality of the grazing by waterfowl on submerged vegetation. / Växtätande sjöfåglars diet består huvudsakligen av undervattensvegetation. Fåglarna betar av växterna oftast under ytan, men undervattensvegetationens biomassa och artsammasättning påverkas inte bara av sjöfåglar, utan också av en rad andra faktorer, till exempel vattnets grumlighet, påväxtalger och vattentemperatur. Syftet med denna litteraturstudie var att undersöka under vilka förutsättningar betning från sjöfåglar har betydelse för undervattensvegetation. Växternas biomassa har visats minska i samband med sjöfåglars födointag, om den huvudsakligen består av vattenväxlighet. Vegetationens täthet varierar under året men uppnår störst täthet under sommaren. Sjöfåglar har visats vara i störst täthet under höstmånaderna, i samband med flyttning. Experimentella studier har genomförts genom att jämföra skyddade områden där sjöfåglar utestängts med öppna områden där sjöfåglar kunnat beta. I de skyddade områdena var växterna generellt längre och hade flera skott. Där fanns också färre stubbar än i de öppna områdena. Flera studier har visat att sjöfåglarna påverkar vegetationens biomassa på olika sätt men det är fortfarande osäkert i vilken grad och om detta över längre tid har en negativ eller positiv påverkan på vegetationens artsammansättning. I och med nutida klimatförändringar kan sjöfåglars tidpunkt och plats för migration och övervintring att förändras. Detta kan leda till att sjöfåglarna inte emigrerar från sjöar och kommer därav med största sannolikhet påverka undervattensvegetationen.

Demand curves were estimated for waterfowl hunting and nonconsumptive recreational use from use rate and variable expenditure data collected at the Bear River Migratory Bird Refuge and the Farmington Bay Waterfowl Management Area during fiscal 1969. Consumer's surplus and monopoly revenue estimates were then derived from the demand functions. Adjusted estimates of consumer's surplus for waterfowl hunting amounted to $7,260 per year at Bear River and $11,400 per year at Farmington Bay. For nonconsumptive recreation annual consumer's surplus was estimated to be $18,700 at Bear River and $3,760 at Farmington Bay. Monopoly revenue estimates were between one-half and one-fourth the corresponding consumer's surplus estimates. The capitalized value (at 8 percent interest) of predicted annual consumer's surplus for all recreation was $865,800 for Bear River and $299,000 for Farmington Boy. Capitalization of the corresponding monopoly revenue estimates gave $276,900 for Bear River and $92,100 for Farmington Bay. At 3 percent interest, the capitalized consumer's surplus values increase to $4,242,000 for Bear River and $1,184,000 for Farmington Buy, while those for monopoly revenue increase to $1,330,000 for Bear River and $350,000 for Farmington Bay. The author believes that consumer's surplus estimates are more valuable than monopoly revenue estimates for comparison with other values included in the benefit/cost analysis of water development projects because the needed values include more than a non-discriminating monopolist can extract. It will never be possible to make additive estimates of all of the relevant values of natural areas used for outdoor recreation. Allocation decisions must draw on several disciplines in addition to economics to determine where the balance will swing for the greatest net benefit to society, nevertheless, the author believes that exceptions exist where the native flora and fauna can be managed to attract visitors such than an area can remain in natural production in perpetuity and be competitive with potentially conflicting interests in terms of measurable economic values. It is believed that future research should concentrate on high-value sites and be directed toward sensitivity analysis, the simultaneous evaluation of alternative uses, the influence of the travel-time variable, marginal resource values, and off-site benefits.

Seasonal utilization of sago pondweed (Potamogeton pectinatus L.) by waterfowl was studied at Bear River Miqratory Bird Refuge by comparing amounts of sago production on a series of plots on Unit Four. One plot was available to carp and waterfowl; one only to carp; and one available to neither. The cage used to eliminate carp and waterfowl use of a plot caused a significant increase in sago production. The increase was attributed to less turbidity and less wind and wave action within the cage. Carp distribution was limited to deep-water portions of Unit Four, a small area, and they had no significant effect on sago production. Therefore, sago production from carp and open plots was compared to determine utilization of sago by waterfowl. Waterfowl utilization of sago in summer and spring was not significant; however, 52 percent of the tuber crop was used by waterfowl in fall. The method of study did not allow detection of waterfowl use of windrowed or submersed seed. Water depths between 2 and 10 inches had little or no effect on waterfowl use of tubers in fall; however depths between 5 and 14 inches in spring and 4 and 13 inches in summer may have prevented full use of tubers. Tubers were most available to ducks in the first 6 inches of soil but were utili zed to 8 inch depths. A series of 50 foot-square pens (2,500 square feet) were stocked with semi-domestic mallards to determine the effect of certain levels of utilization on sago growth. Sago seemed to recover well after heavy spring utilization. Results concerning the effect of summer utilization on production were not conclusive. Sago recovered well in spring after waterfowl had consumed 52 percent of the tuber crop the previous fall.