The goal of the Aquatic Indicators of Land Condition (AILC) project is to develop analytical tools that integrate land condition information with stream condition for improved watershed management within the United States Bureau of Land Management (BLM). Based on the goal of the AILC, two objectives for this study were: to determine the effect of four GIS-derived distance measurements on potential relationships between common BLM landscape stressors (mining and grazing) and changes in benthic macroinvertebrate community structure; and to assess the effectiveness of individual questions on a commonly-used Bureau-wide qualitative stream assessment protocol, the proper functioning condition (PFC) assessment. The four GIS distance measurements assessed for biotic relevance included: straight-line distance, slope distance, flow length, and travel time. No significant relationships were found between the measured distance to stressor and macroinvertebrate community structure. However, the hydrological relevance of flow length and travel time are logically superior to straight-line and slope distance and should be researched further. Several individual questions in the PFC assessment had statistically significant relationships with the final reach ratings and with field-measured characteristics. Two of the checklist questions were significantly related to the number of cow droppings. This may indicate a useful and efficient measure of stream degradation due to grazing. The handling and use of the PFC assessment within the BLM needs further documentation and examination for scientific viability, and the addition of quantitative measurements to the PFC in determining restoration potential would be desirable. / Master of Science

Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / The widespread ecological impacts of overgrazing by livestock within the Succulent Karoo have received considerable attention. Literature shows communal and commercial rangelands have been thoroughly studied, and vegetation responses have been investigated in an attempt to understand the effects of overgrazing. Regarding animal species, literature is in short supply. In a one-year study of small mammal assemblages, the effect of the rangelands, and subsequently vegetation, on small mammal assemblages was examined, as well as the effects on number of occupied, unoccupied and collapsed burrows. This study shows that vegetation composition differs between rangelands, with a greater perennial shrub cover on the communal rangelands and a greater perennial succulent cover on commercial rangelands, consequently creating different habitats for animal assemblages. This study supports the notion of small mammal composition relating to vegetation structure, with certain species being impacted by heavy grazing. Four small mammal species were found in greater abundances on commercial rangelands, with one being exclusive, while communal rangelands were exclusively occupied by three nocturnal species. Diet and habitat requirements are the most important factors regarding species occurrence. With small mammal species composition differing between rangelands, and species richness not being affected by rangeland type, this study illustrates that the disappearance of certain species may arise without these different rangelands. This could result in reduced species richness, and thus diversity being lost. Regarding species present on both rangelands, no differences were observed in body mass, body size or body condition. Despite no differences found in body condition, calculating a body condition index is a good method for investigating how a species is coping within an environment. The proportion and number of occupied and collapsed burrows can be seen as a measure of trampling effect. It was expected for grazing intensity, as well as vegetation changes, to affect the occurrence of such burrows. This study showed differences between the communal and commercial rangelands as negligible. As expected, numbers of burrowing small mammal species were negatively correlated with numbers of collapsed burrows. However, a lack of consistency deemed this result unimportant. Results show that the effects of overgrazing on small mammal populations are complex and require more attention if to be fully explained. This study provides insights into the effects of land use on small mammals and burrow numbers, which have implications for the conservation of these species within arid regions.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-06-23T15:19:36Z No. of bitstreams: 1 TiagoClossDeMarchi.pdf: 3447572 bytes, checksum: 384491c29d57ca52c59ea0cda6879c8b (MD5) / Made available in DSpace on 2015-06-23T15:19:36Z (GMT). No. of bitstreams: 1 TiagoClossDeMarchi.pdf: 3447572 bytes, checksum: 384491c29d57ca52c59ea0cda6879c8b (MD5) Previous issue date: 2011 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A mudança do uso da terra decorrente de atividades agrícolas provoca uma modificação na paisagem que leva à criação de fragmentos florestais isolados que se mantém imersos em uma matriz que pode apresentar uma maior ou menor agressividade de acordo com o seu uso. Este estudo foi realizado em duas fazendas vizinhas localizadas no município de Eldorado do Sul, RS. A Fazenda Terra Dura, pertence à empresa Celulose Riograndense S/A e a maior parte da área é utilizada para a monocultura de eucalipto (Eucalyptus spp.). Os remanescentes de floresta nativa estão exclusivamente associados aos diversos cursos d’água que cruzam a área e cercados pelo plantio de eucalipto de diversas idades e estágios de produção. A área é utilizada para o plantio de eucalipto há cerca de 30 anos e há 20 foi isolada do gado. A Fazenda Eldorado destina-se à criação extensiva de gado e sua cobertura vegetal é caracterizada por um predomínio de campo com fragmentos de florestas ripárias que o gado utiliza como local de pastejo e desedentação. Em cada uma das dez áreas selecionadas foram alocados dois transectos paralelos ao curso d’água a 20 metros de distância um do outro nos quais foram aleatorizadas cinco unidades amostrais de 10 x 10m para amostragem do componente arbóreo dos fragmentos. Em cada unidade amostral foram registradas a circunferência de todos os indivíduos com diâmetro a altura do peito maior ou igual a 5 cm (DAP ≥ 5cm). O componente juvenil foi amostrado em unidades amostrais de 5 x 5m concêntricas em cada parcela de 10 x 10m, onde foram amostrados todos os indivíduos com mais de um metro de altura e com menos de 5 cm de diâmetro e estimou-se sua altura total e seu diâmetro à altura do solo (DAS). A densidade e composição do estrato herbáceo foi amostrada em parcelas de 1 x 1 m concêntricas às unidades amostrais de 5 x 5 m. Nestas unidades amostrais foi removida toda vegetação de até 1 m de altura e identificadas taxonômicamente as espécies e separadas em formas de vida (árvore, arbusto, erva, gramíneas, pteridófita, trepadeiras, epífitos). Para avaliação do sub-bosque nos plantios de eucalipto foram selecionados quatro talhões onde foram alocados três transectos de 100 m de comprimento em diferentes distâncias da borda (5, 25 e 50 m) e dois transectos (5 e 25 m) para o interior da mata ciliar. Em cada transecto foram sorteadas cinco unidades amostrais de 5 x 5 m e amostrados todos os indivíduos juvenis utilizando os mesmos critérios anteriormente citados para este estrato. Nos fragmentos adjacentes aos plantios de eucalipto, foram encontradas 61 espécies para os adultos e 77 para os juvenis e o estoque de carbono estimado foi de 106 Mg.ha-1 para os indivíduos adultos e de 4,3 Mg.ha-1 para os herbáceos. Nas áreas com presença de gado foram amostradas 62 espécies para os adultos e 48 para juvenis, com um estoque de carbono de 85,5 Mg.ha-1 para adultos e 0,9 Mg.ha-1 para herbáceo. No sub-bosque dos plantios de eucalipto foram amostradas 32 espécies, sendo 16 exclusivas e 71 no interior da floresta ripária, com 55 exclusivas. Os resultados mostraram que florestas em pequenos fragmentos incorporados em plantações de eucalipto parecem ser melhor preservadas do que aqueles expostos à pecuária. Além disso, áreas com presença de gado apresentaram uma redução no estoque de carbono de 23,8% para o estrato arbóreo e de 79,4% no estrato herbáceo em relação às áreas sem a presença de gado. A plantação de eucalipto possui um importante papel, embora restrito devido ao curto período de corte das árvores, para a manutenção da diversidade de espécies de florestas nativas adjacentes em seu sub-bosque e podem atuar como uma catalizadoras da regeneração da vegetação nativa e na manutenção da diversidade local. / The change in land use due to agricultural activities causes a landscape change that leads to the creation of isolated forest fragments that remain embedded in a matrix that may present a greater or lesser aggressiveness according to their use. The environmental quality of this matrix can affect species composition and forest structure through several factors that impact the surrounding environment, but on the other hand, depending on its type, the array can act as an important source of biodiversity conservation. This study was conducted in two neighboring farms located in Eldorado do Sul, RS. Terra Dura Farm, owned by Celulose Riograndense S/A and most of the area is used for the monoculture of eucalyptus (Eucalyptus spp.). The remnants of native forest are exclusively associated with the various streams that cross the area and surrounded by eucalyptus plantations of various ages and stages of production. The area is used for the planting of eucalyptus during 30 years. The cattle was isolated 20 years ago. Eldorado Farm is intended for extensive cattle ranching and its vegetation is characterized by a predominance of field with fragments of riparian forests that livestock use for grazing. We survey ten riparian fragments, five in each farm, were allocated two transects parallel to the stream to 20 m away from each other in which five were randomized plots of 10 x 10 m sampling of the tree component of the fragments. In each sampling unit circumference were recorded for all individuals with diameter at breast height greater than or equal to 5 cm (DBH ≥ 5 cm). The juvenile component was sampled in 5 x 5 m plots concentric in each plot of 10 x 10 m was sampled all individuals with more than one meter in height and less than 5 cm in diameter and estimated its total height, and its diameter at ground level (DAS). The density and composition of the herbaceous layer was sampled in plots of 1 x 1 m plots of concentric to 5 x 5 m. In these sample units of all vegetation was removed up to 1 m high, which were taxonomically identified and separated in life forms (tree, shrub, herb, grass, fern, lianes and epiphytes). To evaluate the understory in the eucalyptus plantations were selected four plots were allocated three transects of 100 m length at different distances from the edge (5, 25 and 50 m) and two transects (5 and 25 m) into the riparian vegetation. In each transect were randomly selected five samples of 5 x 5 m and sampled all juveniles using the same criteria previously cited for this stratum. In fragments adjacent to eucalyptus plantations, 61 species were found for adults and 77 for juveniles and the estimated carbon storage was 106 Mg.ha-1 for adults and 4.3 Mg.ha-1 for the herbs. In areas with presence of cattle were sampled for 62 adults and 48 for juveniles, with a carbon stock of 85.5 Mg.ha-1 for adults and 0.9 Mg.ha-1 for herbaceous. In the understory of the eucalyptus plantations were found 32 species, with 16 exclusive and 71 within the riparian forest, with 55 exclusive. Our results showed that in small forest fragments embedded in eucalypt plantations seem to be better preserved than those exposed to livestock. In addition, areas with the presence of cattle showed a reduction in carbon stock of 23.8% for the upper stratum and 79.4% in the herbaceous layer compared to areas without the presence of livestock and the planting of eucalyptus has an important role, although limited, due to shortcut the trees for the maintenance of species diversity of native forest adjacent to their understory and can act as a catalyst of the regeneration of native vegetation and maintenance of local diversity.

No description available.