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The effects of two forms of mid-rotation release on thinned, fertilized loblolly pine (Pinus taeda L.) plantations in Virginia were examined: aerial imazapyr and basal triclopyr application. Imazapyr measurement plots were installed in nine Piedmont and twelve Coastal Plain plantations operationally released with imazapyr, and triclopyr measurement plots were installed within a controlled fertilization/release study spanning both regions. No differences in volume were detected following triclopyr release. All release dates combined, Piedmont released areas averaged 0.06 m3/tree (18%) greater than the control and Coastal Plain released areas averaged 0.05 m3/tree (14%) greater than the control. Reductions in hardwood basal area, stem density, and shrub stratum cover were observed for both forms of release. Reductions in shrub stratum richness and diversity were also documented for imazapyr release; however, trends indicate that richness and diversity, as well as stem density and shrub stratum cover, may recover to pre-treatment levels. Herbaceous vegetation was increased on triclopyr sites, which was reflected in an elevated turkey (Meleagris gallopavo sylvestris L.) food/brood index. Following imazapyr release, habitat suitability index (HSI) values for pine warblers (Dendroica pinus L.) and black-capped chickadees (Parus atricapillus L.) increased due to reductions in canopy hardwoods and increases in snags. Reduced shrub stratum density resulted in a lower bobwhite quail (Colinus virginianus L.) cover index on imazapyr-released areas. / Master of Science

Tropical peatlands have some of the highest carbon densities of any ecosystem and are under enormous development pressure. This dissertation aimed to provide better estimates of the scales and trends of ecological impacts from tropical peatland deforestation and degradation across more than 7,000 hectares of both intact and disturbed peatlands in northwestern Borneo. We combined direct field sampling and airborne Light Detection And Ranging (LiDAR) data to empirically quantify forest structures and aboveground live biomass across a largely intact tropical peat dome. The observed biomass density of 217.7 ± 28.3 Mg C hectare-1 was very high, exceeding many other tropical rainforests. The canopy trees were ~65m in height, comprising 81% of the aboveground biomass. Stem density was observed to increase across the 4m elevational gradient from the dome margin to interior with decreasing stem height, crown area and crown roughness. We also developed and implemented a multi-temporal, Landsat resolution change detection algorithm for identify disturbance events and assessing forest trends in aseasonal tropical peatlands. The final map product achieved more than 92% user’s and producer’s accuracy, revealing that after more than 25 years of management and disturbances, only 40% of the area was intact forest. Using a chronosequence approach, with a space for time substitution, we then examined the temporal dynamics of peatlands and their recovery from disturbance. We observed widespread arrested succession in previously logged peatlands consistent with hydrological limits on regeneration and degraded peat quality following canopy removal. We showed that clear-cutting, selective logging and drainage could lead to different modes of regeneration and found that statistics of the Enhanced Vegetation Index and LiDAR height metrics could serve as indicators of harvesting intensity, impacts, and regeneration stage. Long-term, continuous monitoring of the hydrology and ecology of peatland can provide key insights regarding best management practices, restoration, and conservation priorities for this unique and rapidly disappearing ecosystem.

<p>An ecosystem is a community of organisms interacting with its environment, and landscapes are spatially interactive ecosystems. Earth's burgeoning human population demands ever more from finite ecosystems; but if managed well, landscapes can sustain their provision of resources and services and adapt to fulfill the changing human appetite. Management relies on sound information, and managing landscape change requires reliable spatio-temporal databases of ecologically relevant information. Remote sensing technologies fill this niche, providing increasingly large and diverse datasets, but the algorithms to extract information from the data must be developed. I developed and compared three remotely sensed measurements of forest canopy height to one another and to in situ field measurements. Both the precision and the accuracy (as well as the cost) of the measurements sorted along an axis of spatial scale, with Light Detection and Ranging (lidar) measurements proving most reliable at fine scales but prohibitively expensive over large areas and various radar technologies more appropriate for larger areas, especially when calibrated to the more accurate and precise lidar measurements. I also adapted traditional, single-time landcover classification algorithms to extract dense time series of categorical landcover maps from archival multi-spectral satellite images. These measurements greatly expand the potential spatio-temporal scope of landscape ecology and management, facilitating a shift away from data-imposed reliance on "space-for-time substitution" and loosely connected case studies toward robust, statistical analysis based on consistent information.</p> / Dissertation

The objective of this thesis was to examine whether forest structure and ground vegetation could explain the habitat choices of the reindeer within similar forest stands. The field work was carried out on 60 sites scattered across a part of the winter grounds for Vilhelmina Norra reindeer herding district. All sites were situated within so-called core and key areas, i.e. areas which the herding district sees as necessary for the reindeer husbandry in the area. Information from GPS-collared reindeer were used to create RIVO (by the Reindeer Identified [as] Important Areas) maps, where areas the reindeer preferred were shown. The results showed that the core and key areas were not significantly different from each other regarding the forest structure, nor the vegetation, but there were some differences in terms of the habitat choice of the reindeer and when the core and key areas were combined with RIVO. The differences concern mainly the coverage of ground lichens, epiphytic lichens and moose presence. Results from other studies suggest that the reindeer habitat selection is dependent on the weather and snow conditions, and looks very different from year to year. The snow conditions are in turn affected by the forest structure, so it is important that the grazing grounds have a heterogeneous forest landscape, including areas which under normal circumstances would not be seen as important for the reindeer husbandry.

While traditional management of the boreal forests results in even-aged forests with low landscape scale variability, recent work has suggested that much of the eastern boreal forest of North America is subject to long natural fire return-intervals. This has led to the development of new management strategies to maintain a mosaic of even and multi-aged stands. In this context I investigated the relationships between diameter-distributions, stand age, forest structure and bird communities. Results showed weak associations of the bird community with cohort classes, but that diameter-distributions can work to succinctly describe some of the variation in stand structure and bird communities. I also explored the utility of LiDAR to measure important structural features for bird communities. Results showed that LiDAR can outperform traditional measures of stand structure at explaining bird communities at differing scales.

While traditional management of the boreal forests results in even-aged forests with low landscape scale variability, recent work has suggested that much of the eastern boreal forest of North America is subject to long natural fire return-intervals. This has led to the development of new management strategies to maintain a mosaic of even and multi-aged stands. In this context I investigated the relationships between diameter-distributions, stand age, forest structure and bird communities. Results showed weak associations of the bird community with cohort classes, but that diameter-distributions can work to succinctly describe some of the variation in stand structure and bird communities. I also explored the utility of LiDAR to measure important structural features for bird communities. Results showed that LiDAR can outperform traditional measures of stand structure at explaining bird communities at differing scales.

Habitat fragmentation and destruction caused by development of infrastructure such as roads threaten biodiversity. Roads act as barriers by impeding animal movements and restricting space use. Understanding factors that influence barrier effects is important to discern the impacts of habitat fragmentation and to develop appropriate mitigations. We combined telemetry and demographic data in 2008 to 2012 with remote sensing imagery to investigate barrier effects of forest roads and assess effects of traffic, road edges, and canopy gaps on space use of an endangered, endemic forest obligate, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis). We mapped low to high traffic roads, road edges, canopy gaps, and random lines in forests to serve as references. We determined if red squirrels included these linear features in their total and core home ranges, and used this metric as an indicator of crossing and preference for habitat adjacent to the linear features. Forest roads acted as barriers regardless of traffic volume and had long-term impacts on animal space use. Animals did not avoid entering roadside areas, and probability of crossing linear features in the forest was not affected by distance to roads. In contrast, greater canopy cover increased probability of crossing, and gaps in canopy impeded animal movements. Higher likelihood of road crossing was associated with more variable tree height and mating activity. We demonstrated that narrow forest roads with low traffic volume were barriers for forest dependent species, and suggest that gap avoidance inhibits road crossings. (C) 2016 Published by Elsevier Ltd.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-08T13:00:23Z No. of bitstreams: 1 brunocorreabarbosa.pdf: 2267476 bytes, checksum: fc4bba809375fb826f5c8f792384423e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-09T13:40:49Z (GMT) No. of bitstreams: 1 brunocorreabarbosa.pdf: 2267476 bytes, checksum: fc4bba809375fb826f5c8f792384423e (MD5) / Made available in DSpace on 2015-12-09T13:40:49Z (GMT). No. of bitstreams: 1 brunocorreabarbosa.pdf: 2267476 bytes, checksum: fc4bba809375fb826f5c8f792384423e (MD5) Previous issue date: 2015-02-13 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As vespas sociais são de grande importância nos ecossistemas florestais pelo seu papel ecológico na regulação da população de outros insetos. Apesar de muitos trabalhos sobre diversidade estrem sendo publicados nos últimos anos, ainda existem muitas lacunas no território Brasileiro, destacando as comunidades de vespas sociais associadas à os dosséis florestais que são ainda largamente inexplorados. Os fragmentos urbanos ou Novel ecosystems estão recebendo destaque nos últimos anos devido seu papal de “refúgios” para biodiversidade. O presente estudo teve como objetivo central o levantamento das espécies de vespas sociais em um fragmento urbano, com base na riqueza encontrada foi estudado a sazonalidade da distribuição espacial das vespas durante as estações, assim como a criar de redes de interseção para o entendimento de preferencias de nidificação em man-made substrates e plantas. Para o estudo de diversidade e estratificação, forem realizadas durante 24 meses, coletas mensais utilizando os métodos de Busca Ativa, Busca por Ninhos e Armadilha atrativa, e para criação das redes de interação foram realizados 43 meses de coletas mensais utilizado metodologia de Busca por Ninhos. Foram encontradas 36 espécies de vespas de 10 gêneros, a riqueza encontrada é o decimo maior trabalho de levantamento no Brasil e quinto no estado de Minas Gerais, nenhum método utilizado foi capas de capturar todas as espécies de vespas, mostrado a necessidade de um consórcio de métodos. A estratificação mostrou uma variação ao longo das estações do ano, demostrado que as vespas utilizam o estrato dossel na época de estiagem e sub-bosque na época chuvosa, coletando espécies exclusivas para cada estrato, tendo dossel seis exclusivas e sub-bosque duas. A rede de interação abrigou 23 espécies de vespas sociais, 35 espécies de plantas e sete man-made substrates. Em ambas as redes foi encontrada assimetria, com um grande número de espécies de vespas, plantas e man-made substrates. No aspecto geral, a maioria das vespas teve baixa amplitude de sitio para nidificação, fundando de dois a quatro espécies de plantas/substratos. Os dados sugerem que as diferenças na complexidade estruturais do ambiente influenciam diretamente a estrutura da rede de interação entre vespas sociais e substratos para nidificação. Os resultados contribuem para o aumento do conhecimento sobre a riqueza das vespas sociais na região sudeste e evidencia a capacidade de forrageio vertical das vespas sociais de acordo com a estação do ano em ambientes de Novel ecosystems. / The social wasps are of great importance in forest ecosystems for their ecological role in regulating the population of other insects. Although many studies on diversity are being published in recent years, there are still many gaps in the Brazilian territory, highlighting the social wasps communities associated with forest canopies that are still largely unexplored. “Urban green areas” or Novel ecosystems are received attention in recent years due to its role of "refuges" for biodiversity. This study aimed mainly at the checklist of species of social wasps in an urban fragment, based on the wealth found was studied seasonality of the spatial distribution of wasps during the seasons, as well as create intersecting networks for the understanding of preferences nesting in man-made substrates and plants. For the study of diversity and stratification, are carried out for 24 months monthly collections using the methods of Active Search, Searching for Nests and Attractive Trap, and for creation of interaction networks were performed 43 months of monthly sampling methodology used Search for Nests. Were found 36 species of wasp of 10 genera, the wealth found is the tenth largest work of the checklist in Brazil and the fifth in the state of Minas Gerais, no method was used to capture covers all species of wasps, shown the need for a consortium of methods. The stratification showed a variation throughout the seasons of the year, showing that the wasps use the canopy layer in the dry season and undergrowth in the rainy season, collecting exclusive species for each stratum, with six exclusive for canopy and two for undergrowth. The interaction network harbored 23 species of social wasps, 35 species of plants and seven man-made substrates. In both, systems asymmetry was observed with a large number of species of wasps, plants and man-made substrates. In general appearance, most wasps had low amplitude site for nesting, founding in two to four species of plants/substrates. The data suggest that differences in environmental structural complexity directly influence the structure of the network of interaction between social wasps and substrates for nesting. The results contribute to increased knowledge about the wealth of social wasps in the southeast region and show the vertical foraging capacity of social wasps according to the season in Novel ecosystems environments.

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