568 resultados para riparian


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In this study alpha and beta diversity patterns of five leaf litter arthropod groups (ants, predatory ants, oribatid mites, spiders and other arachnids) were described and compared in 39 sampling patches of a transformed landscape in southwestern Colombia, that represented five vegetation types: secondary forest, riparian forest, giant bamboo forest, pasture and sugarcane crop. It was also assessed whether some taxa could be used as diversity surrogates. A total of 6,765 individuals grouped in 290 morphospecies were collected. Species richness in all groups was lower in highly transformed vegetation types (pasture, sugarcane crop) than in native ones (forests). In contrast, there were no clear tendencies of beta diversity among vegetation types. Considering sampling patches, 0.1-42% of the variation in alpha diversity of one taxonomic group could be explained from the alpha diversity of another, and 0.2-33% of the variation of beta diversity of a given taxon was explained by that in other groups. Contrary to recent findings, we concluded that patterns of alpha diversity are more congruent than patterns of beta diversity. This fact could be attributed to a sampling effect that promotes congruence in alpha diversity and to a lack of a clear regional ecological gradient that could promote congruent patterns of beta diversity. We did not find evidence for an ideal diversity surrogate although diversity patterns of predatory ants had the greatest congruencies. These results support earlier multi-taxon evaluations in that conservation planning should not be based on only one leaf litter arthropod group.

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Freshwater fish that live exclusively in rivers are at particular risk from fragmentation of the aquatic system, mainly the species that migrate upriver for reproduction. That is the case of Salminus hilarii, an important migratory species currently classified as “almost threatened” in the São Paulo State (Brazil), facing water pollution, dam construction, riparian habitat destruction and environmental changes that are even more serious in this State. Additionally, this species show ovulation dysfunction in captivity. Our studies focused on the identification and distribution of the pituitary cell types in the adenohypophysis of S. hilarii females, including a morphometric analysis that compares pituitary cells from wild and captive broodstocks during the reproductive annual cycle. The morphology of adenohypophysial cells showed differences following the reproductive cycle and the environment. In general, optical density suggested a higher cellular activity during the previtellogenic (growth hormone) and vitellogenic (somatolactin) stages in both environments. Additionally, the nucleus/cell ratio analysis suggested that growth hormone and somatolactin cells were larger in wild than in captive females in most reproductive stages of the annual cycle. In contrast, prolactin hormone showed no variation throughout the reproductive cycle (in both environments). Morphometrical analyses related to reproduction of S. hilarii in different environmental conditions, suggest that somatolactin and growth hormone play an important role in reproduction in teleost and can be responsible for the regulation of associated processes that indirectly affect reproductive status.

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Zonas ripárias são áreas de saturação hídrica, permanente ou temporária, cuja principal função é a proteção dos recursos hídricos de uma microbacia. Essa pesquisa comparou a adequação do uso do solo de dois cenários de planejamento agrícola de uma microbacia: o cenário convencional, representando o método usualmente empregado, que apenas considera as classes de capacidade de uso da terra, e o cenário hidrológico, que inclui a delimitação e avaliação das zonas ripárias. Um estudo de caso foi realizado na Microbacia do Ribeirão São João (3.656 ha), no município de Mineiros do Tietê (São Paulo, Brasil). Mapas de Classe de Capacidade de Uso da Terra e de Adequação do Uso do Solo foram elaborados, utilizando o Sistema de Informação Geográfica (SIG), para a construção dos cenários convencional e do proposto. Excluindo a Área de Preservação Permanente (APP), o cenário convencional indicou que 59,0% da área destinada à agricultura está adequadamente utilizada, 28,2% está subutilizada e 2,6% está sobreutilizada. O cenário proposto ou hidrológico, com inclusão da identificação da zona ripária (24,9% da microbacia) mostrou que muitas áreas que, no cenário convencional, possuem pouca restrição para o cultivo intensivo, como as classes II e III, são zonas ripárias, de sensibilidade hidrológica. Existem dentro dos limites da zona ripária 38,9% de classe de capacidade de uso III e 49,5% de classe IV. O planejador, desconsiderando a zona ripária, pode colocar em risco áreas vitais que, se degradadas, representam danos para a saúde e resiliência da microbacia.

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O presente artigo visa a contribuir para os diálogos sobre políticas públicas relacionadas à conservação e restauração de matas ciliares no estado de São Paulo, considerando as possibilidades de participação social em sua formulação e implementação. A pesquisa que gerou as considerações aqui apresentadas baseou-se na análise da implementação e dos resultados do Projeto de Recuperação de Matas Ciliares (PRMC), uma intervenção conduzida pela Secretaria de Estado de Meio Ambiente do Estado de São Paulo (SMA-SP) visando a gerar subsídios para a elaboração de um programa de longo prazo de conservação e restauração de matas ciliares nesse Estado. O método de pesquisa incluiu a análise de documentos oficiais referentes ao projeto de intervenção; entrevistas qualitativas com funcionários dos quadros da SMA-SP e da Secretaria de Agricultura e Abastecimento do Estado de São Paulo - SAA-SP, esta última corresponsável pela implantação do projeto; além de entrevistas semi-estruturadas com proprietários rurais e representantes das organizações não governamentais envolvidas na execução dos projetos-piloto implementados durante o PRMC. A pesquisa mostra que as dificuldades de integração intra e interinstitucional - entre as coordenadorias e departamentos da SMA-SP, e desta com a SAA-SP - bem como a falta de priorização da participação, mobilização social e educação ambiental no PRMC, foram os principais fatores limitantes para o sucesso do Projeto no recorte aqui tratado.

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This study investigates the species richness and abundance of Drosophila Fallén, 1823 attracted to dung and carrion baited pitfall traps in natural areas with heterogeneous habitats at the Sierra de Minas, Eastern Serranías, southeastern Uruguay. Collecting was carried out on a monthly basis (May 2002 through April 2003). Drosophilids accounted for 0.84% (n = 131) and 3.61% (n = 158) of the Diptera collected from dung (n = 15,630) and carrion (n = 4,382) pitfall traps, respectively. A total of 12 species were identified, 11 of which belong to the subgenus Drosophila (the richest) and one to the subgenus Sophophora Sturtevant, 1939. Over 90% of the Drosophila specimens collected belong to five species of the subgenus Drosophila, namely D. gaucha Jaeger & Salzano, 1953, D. immigrans Sturtevant, 1921, D. mediovittata Frota-Pessoa, 1954, D. aff. nappae Vilela, Valente & Basso-da-Silva, 2004, and D. ornatifrons Duda, 1927. Drosophila cardini Sturtevant, 1916 is recorded for the first time from Uruguay. Drosophila abundance and species richness in the four habitats sampled in the Uruguayan Eastern Serranías, namely woodlands sierra, riparian forest, pine plantation and grazing grassland, were considered to be a function of habitat conservation. Diversity indices were low in all habitats. Different habitats supported particular coprophilous and necrophilous Drosophila species. The woodland sierra represents the most preserved habitat, and contributed with the highest species richness observed. Drosophila ornatifrons was the dominant species, with a restricted habitat distribution. On the other hand, grazed grassland, an environment modified by livestock management, had the lowest species richness: only a few specimens of D. repleta Wollaston, 1858. Regarding species composition, significant differences were found in some pairwise comparisons of groups of Drosophila species that included D. ornatifrons. Fly attraction to dung can be exploited as an alternative and/or complementary collecting method in ecological studies of Drosophila assemblages in natural areas.

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This study aimed to map phytophysiognomies of an area of Ombrophilous Dense Forest at Parque Estadual da Serra do Mar and characterize their floristic composition. Photointerpretation of aerial photographs in scale of 1:35,000 was realized in association with field work. Thirteen physiognomies were mapped and they were classified as Montane Ombrophilous Dense Forest, Alluvial Ombrophilous Dense Forest or Secondary System. Three physiognomies identified at Casa de Pedra streamlet's basin were studied with more details. Riparian forest (RF), valley forest (VF), and hill forest (HF) presented some floristic distinction, as confirmed by Detrended Correspondence Analysis (DCA) and Indicator Species Analysis (ISA) conducted here. Anthropic or natural disturbances and heterogeneity of environmental conditions may be the causes of physiognomic variation in the vegetation of the region. The results presented here may be useful to decisions related to management and conservation of Núcleo Santa Virgínia forests, in general.

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Freshwater fish that live exclusively in rivers are at particular risk from fragmentation of the aquatic system, mainly the species that migrate upriver for reproduction. That is the case of Salminus hilarii, an important migratory species currently classified as “almost threatened” in the São Paulo State (Brazil), facing water pollution, dam construction, riparian habitat destruction and environmental changes that are even more serious in this State. Additionally, this species show ovulation dysfunction in captivity. Our studies focused on the identification and distribution of the pituitary cell types in the adenohypophysis of S. hilarii females, including a morphometric analysis that compares pituitary cells from wild and captive broodstocks during the reproductive annual cycle. The morphology of adenohypophysial cells showed differences following the reproductive cycle and the environment. In general, optical density suggested a higher cellular activity during the previtellogenic (growth hormone) and vitellogenic (somatolactin) stages in both environments. Additionally, the nucleus/cell ratio analysis suggested that growth hormone and somatolactin cells were larger in wild than in captive females in most reproductive stages of the annual cycle. In contrast, prolactin hormone showed no variation throughout the reproductive cycle (in both environments). Morphometrical analyses related to reproduction of S. hilarii in different environmental conditions, suggest that somatolactin and growth hormone play an important role in reproduction in teleost and can be responsible for the regulation of associated processes that indirectly affect reproductive status.

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The Geoffroy’s bat Myotis emarginatus is mainly present in southern, south-eastern and central Europe (Červerný, 1999) and is often recorded from northern Spain (Quetglas, 2002; Flaquer et al., 2004). It has demonstrated the species’ preference for forest. Myotis capaccinii, confined to the Mediterranean (Guille´n, 1999), is classified as ‘vulnerable’ on a global scale (Hutson, Mickleburgh & Racey, 2001). In general, the species preferred calm waters bordered by well-developed riparian vegetation and large (> 5 m) inter-bank distances (Biscardi et al. 2007). In this study we present the first results about population genetic structure of these two species of genus Myotis. We used two methods of sampling: invasive and non-invasive techniques. A total of 323 invasive samples and a total of 107 non-invasive samples were collected and analyzed. For Myotis emarginatus we have individuated for the first time a set of 7 microsatellites, which can work on this species, started from a set developed on Myotis myotis (Castella et al. 2000). We developed also a method for analysis of non-invasive samples, that given a good percentage of positive analyzed samples. The results have highlighted for the species Myotis emarginatus the presence on the European territory of two big groups, discovered by using the microsatellites tracers. On this species, 33 haplotypes of Dloop have been identified, some of them are presented only in some colonies. We identified respectively 33 haplotypes of Dloop and 10 of cytB for Myotis emarginatus and 25 of dloop and 15 of cytB for Myotis capaccinii. Myotis emarginatus’ results, both microsatellites and mtDNA, show that there is a strong genetic flow between different colonies across Europe. The results achieved on Myotis capaccinii are very interesting, in this case either for the microsatellites or the mitochondrial DNA sequences, and it has been highlighted a big difference between different colonies.

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The biogenic production of NO in the soil accounts for between 10% and 40% of the global total. A large degree of the uncertainty in the estimation of the biogenic emissions stems from a shortage of measurements in arid regions, which comprise 40% of the earth’s land surface area. This study examined the emission of NO from three ecosystems in southern Africa which cover an aridity gradient from semi-arid savannas in South Africa to the hyper-arid Namib Desert in Namibia. A laboratory method was used to determine the release of NO as a function of the soil moisture and the soil temperature. Various methods were used to up-scale the net potential NO emissions determined in the laboratory to the vegetation patch, landscape or regional level. The importance of landscape, vegetation and climatic characteristics is emphasized. The first study occurred in a semi-arid savanna region in South Africa, where soils were sampled from 4 landscape positions in the Kruger National Park. The maximum NO emission occurred at soil moisture contents of 10%-20% water filled pore space (WFPS). The highest net potential NO emissions came from the low lying landscape positions, which have the largest nitrogen (N) stocks and the largest input of N. Net potential NO fluxes obtained in the laboratory were converted in field fluxes for the period 2003-2005, for the four landscape positions, using soil moisture and temperature data obtained in situ at the Kruger National Park Flux Tower Site. The NO emissions ranged from 1.5-8.5 kg ha-1 a-1. The field fluxes were up-scaled to a regional basis using geographic information system (GIS) based techniques, this indicated that the highest NO emissions occurred from the Midslope positions due to their large geographical extent in the research area. Total emissions ranged from 20x103 kg in 2004 to 34x103 kg in 2003 for the 56000 ha Skukuza land type. The second study occurred in an arid savanna ecosystem in the Kalahari, Botswana. In this study I collected soils from four differing vegetation patch types including: Pan, Annual Grassland, Perennial Grassland and Bush Encroached patches. The maximum net potential NO fluxes ranged from 0.27 ng m-2 s-1 in the Pan patches to 2.95 ng m-2 s-1 in the Perennial Grassland patches. The net potential NO emissions were up-scaled for the year December 2005-November 2006. This was done using 1) the net potential NO emissions determined in the laboratory, 2) the vegetation patch distribution obtained from LANDSAT NDVI measurements 3) estimated soil moisture contents obtained from ENVISAT ASAR measurements and 4) soil surface temperature measurements using MODIS 8 day land surface temperature measurements. This up-scaling procedure gave NO fluxes which ranged from 1.8 g ha-1 month-1 in the winter months (June and July) to 323 g ha-1 month-1 in the summer months (January-March). Differences occurred between the vegetation patches where the highest NO fluxes occurred in the Perennial Grassland patches and the lowest in the Pan patches. Over the course of the year the mean up-scaled NO emission for the studied region was 0.54 kg ha-1 a-1 and accounts for a loss of approximately 7.4% of the estimated N input to the region. The third study occurred in the hyper-arid Namib Desert in Namibia. Soils were sampled from three ecosystems; Dunes, Gravel Plains and the Riparian zone of the Kuiseb River. The net potential NO flux measured in the laboratory was used to estimate the NO flux for the Namib Desert for 2006 using modelled soil moisture and temperature data from the European Centre for Medium Range Weather Forecasts (ECMWF) operational model on a 36km x 35km spatial resolution. The maximum net potential NO production occurred at low soil moisture contents (<10%WFPS) and the optimal temperature was 25°C in the Dune and Riparian ecosystems and 35°C in the Gravel Plain Ecosystems. The maximum net potential NO fluxes ranged from 3.0 ng m-2 s-1 in the Riparian ecosystem to 6.2 ng m-2 s-1 in the Gravel Plains ecosystem. Up-scaling the net potential NO flux gave NO fluxes of up to 0.062 kg ha-1 a-1 in the Dune ecosystem and 0.544 kg h-1 a-1 in the Gravel Plain ecosystem. From these studies it is shown that NO is emitted ubiquitously from terrestrial ecosystems, as such the NO emission potential from deserts and scrublands should be taken into account in the global NO models. The emission of NO is influenced by various factors such as landscape, vegetation and climate. This study looks at the potential emissions from certain arid and semi-arid environments in southern Africa and other parts of the world and discusses some of the important factors controlling the emission of NO from the soil.

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Die vorliegende Arbeit ist ein Teil des Projektes Flut und Hitze des Kompetenzzentrums Überflutung an der Universität Mainz. Die Ziele dieser Untersuchung waren: Die Artzusammensetzung und Phänologien der Spinnengemeinschaften von Uferhabitaten bei Mainz (Rheinland-Pfalz, Deutschland) zu ermitteln, anhand des Artenspektrums die Folgen langjähriger Trockenheit und die Auswirkungen des Extremsommers 2003 zu beschreiben, Einflüsse von Überflutungen festzustellen und die Submersionstoleranzen ausgewählter Arten zu bestimmen. Insgesamt wurden 27783 Spinnen aus 179 Arten und 24 Familien bearbeitet. Die Untersuchung umfasste einen Hartholzauwald bei Ingelheim am Rhein, den Hochwasserschutzpolder Ingelheim, sowie Tiermaterial von vier weiteren Uferstandorten und drei Inselstandorten des Rheins bei Mainz. Die Beprobung der Hartholzaue mit Barberfallen und Stammeklektoren erfolgte von Mai 2005 bis Mai 2008. Im Polder wurden von Oktober 2006 bis Mai 2008 mit Barberfallen und einem Vakuumsauger gefangen. Die Proben der weiteren Standorte stammten aus Barberfallenfängen der Jahre 2000 bis einschließlich 2005. In der seit Winter 2002/2003 nicht mehr überfluteten und im Sommer stark austrocknenden Hartholzaue wurde eine als xerotolerant zu bezeichnende Spinnenfauna vorgefunden. Dies galt insbesondere für die sehr artenreiche Stammregion. Zu den dominierenden Spezies zählten: Diplostyla concolor (Boden), Clubiona pallidula und Textrix denticulata (beide Stamm). Der Polder Ingelheim wurde überwiegend von euryöken Freilandbewohnern besiedelt, dominant kamen Oedothorax apicatus und Pardosa agrestis vor. Das Tiermaterial der Ufer- und Inselstandorte wies deutliche Unterschiede in der Artenzusammensetzung im Bezug auf die Flutungsintensität auf. Nach dem Ausbleiben von Hochwässern und dem starken Austrocknen der Standorte im Sommer 2003 wurden hygrobionte Arten wie Allomengea vidua kaum mehr vorgefunden, während sich xerotolerante Spezies ausbreiteten. Darüber hinaus wurden die Submersionstoleranzen ausgewählter Spinnenarten im Labor ermittelt. Die gewonnenen Daten lassen Vermuten, dass die getesteten Spinnenspezies durchaus in der Lage sind, bei niedrigen Wassertemperaturen eine kurze Flut submers zu überstehen. Unter hohen Temperaturen besteht dagegen keine Submersionstoleranz.

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This thesis assesses relationships between vegetation and topography and the impact of human tree-cutting on the vegetation of Union County during the early historical era (1755-1855). I use early warrant maps and forestry maps from the Pennsylvania historical archives and a warrantee map from the Union County courthouse depicting the distribution of witness trees and non-tree surveyed markers (posts and stones) in early European settlement land surveys to reconstruct the vegetation and compare vegetation by broad scale (mountains and valleys) and local scale (topographic classes with mountains and valleys) topography. I calculated marker density based on 2 km x 2 km grid cells to assess tree-cutting impacts. Valleys were mostly forests dominated by white oak (Quercus alba) with abundant hickory (Carya spp.), pine (Pinus spp.), and black oak (Quercus velutina), while pine dominated what were mostly pine-oak forests in the mountains. Within the valleys, pine was strongly associated with hilltops, eastern hemlock (Tsuga canadensis) was abundant on north slopes, hickory was associated with south slopes, and riparian zones had high frequencies of ash (Fraxinus spp.) and hickory. In the mountains, white oak was infrequent on south slopes, chestnut (Castanea dentata) was more abundant on south slopes and ridgetops than north slopes and mountain coves, and white oak and maple (Acer spp.) were common in riparian zones. Marker density analysis suggests that trees were still common over most of the landscape by 1855. The findings suggest there were large differences in vegetation between valleys and mountains due in part to differences in elevation, and vegetation differed more by topographic classes in the valleys than in the mountains. Possible areas of tree-cutting were evenly distributed by topographic classes, suggesting Europeans settlers were clearing land and harvesting timber in most areas of Union County.

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A Framework for a Consultation Process: Transboundary cooperation and sustainable water management is urgently needed in the up-stream/down-stream situation of the Umbeluzi River Basin between the Kingdom of Swaziland and the Republic of Mozambique. Thus, the Joint Water Commission (JWC) of the two riparian countries initiated the Umbeluzi River Basin Initiative (URBI) with the objective to develop a joint management plan of the river basin. In response to the request by SADC as well as SDC, a collaboration within CDE’s Eastern and Southern Africa Partnership Programme ESAPP was agreed upon. The project’s general objective is to provide conceptual and methodological support in the design of a consultative process with the aim to assure the participation of all water users within the river basin.

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In order to find out which factors influenced the forest dynamics in northern Italy during the Holocene, a palaeoecological approach involving pollen analysis was combined with ecosystem modelling. The dynamic and distribution based forest model DisCForm was run with different input scenarios for climate, species immigration, fire, and human impact and the similarity of the simulations with the original pollen record was assessed. From the comparisons of the model output and the pollen core, it appears that immigration was most important in the first part of the Holocene, and that fire and human activity had a major influence in the second half. Species not well represented in the simulation outputs are species with a higher abundance in the past than today (Corylus), with their habitat in riparian forests (Alnus) or with a strong response to human impact (Castanea).

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In order to maintain pond-breeding amphibian species richness, it is important to understand how both natural and anthropogenic disturbances affect species assemblages and individual species distributions both at the scale of individual ponds and at a larger landscape scale. The goal of this project was to investigate what characteristics of ponds and the surrounding wetland landscape were most effective in predicting pond-breeding species richness and the individual occurrence of wood frog (Rana sylvatica), bullfrog (Rana catesbeiana) and pickerel frog (Rana palustris) breeding sites in a beaver-modified landscape and how this landscape has changed over time. The wetland landscape of Acadia National Park was historically modified by the natural disturbance cycles of beaver (Castor cazadensis), and since their reintroduction to the island in 1921, beaver have played a large role in creating and maintaining palustrine wetlands. In 2000 and 2001, I studied pond-breeding amphibian assemblages at 71 palustrine wetlands in Acadia National Park, Mount Desert Island, Maine. I determined breeding presence of 7 amphibian species and quantified 15 variables describing local pond conditions and characteristics of the wetland landscape. I developed a priori models to predict sites with high amphibian species and used model selection with Akaike's Information Criterion (AIC) to identify important variables. Single species models were also developed to predict wood frog, bullfrog and pickerel frogs breeding presence. The variables for wetland connectivity by stream corridors and the presence of beaver disturbance were the most effective variables to predict sites with high amphibian richness. Wood frog breeding was best predicted by local scale variables describing temporary, fishless wetlands and the absence of active beaver disturbance. Abandoned beaver sites provided wood frog breeding habitat (70%) in a similar proportion to that found in non beaver-influenced sites (79%). In contrast, bullfrog breeding presence was limited to active beaver wetlands with fish and permanent water, and 80% of breeding sites were large (≥2ha in size). Pickerel frog breeding site selection was predicted best by the connectivity of sites in the landscape by stream corridors. Models including the presence of beaver disturbance, greater wetland perimeter and greater depth were included in the confidence set of pickerel frog models but showed considerably less support. Analysis of historic aerial photographs showed an 89% increase in the total number of ponded wetlands available in the landscape between the years of 1944 and 1997. Beaver colonization generally converted forested wetlands and riparian areas to open water and emergent wetlands. Temporal colonization of beaver wetlands favored large sites low in the watersheds and sites that were impounded later were generally smaller, higher in the watershed, and more likely to be abandoned. These results suggest that beaver have not only increased the number of available breeding sites in the landscape for pond-breeding amphibians, but the resulting mosaic of active and abandoned beaver wetlands also provides suitable breeding habitat for species with differing habitat requirements.