Managed forest ecosystems contribute to conservation of wildlife, and generally yield heterogeneous landscapes with patches that support different sessile organisms. Edges or boundaries between adjacent forest patches are often ecologically distinct from patch interiors and can have direct influences on community dynamics and ecosystem functioning near them. To quantify effects of edge and adjacent habitat conditions on avian metrics, I used a hierarchical multi-species occupancy model that considered individual species resource requirements to estimate community occupancy patterns, and used artificial nest surveys to model daily nest survival (DNS) using a Bayesian framework. Results indicated that adjacent forest conditions influenced bird population dynamics in focal forest stands, provided little evidence of an edge effect on avian community response patterns, and showed highest DNS in newly established forest stands. My results highlight the importance of considering type and spatial arrangement of different habitat patches for habitat planning operations on managed forest landscapes.

One knowledge gap hindering prairie restoration is uncertainty about when a restored prairie communities sufficiently resemble remnant prairie. I surveyed plant communities in remnant prairies, prairies > 5 years post-restoration, and prairies ≤ 5 years post-restoration in Mississippi. Remnants had the greater species richness. Restored prairies had less cover of woody plants and forbs but greatest non-natives. Restored prairies were not similar to remnant prairies (similarity index = 28.9 - 25.9%), primarily because restored prairies had fewer prairie forbs. Thus, restoration may take decades. Transplanting locallyapted prairie forbs into restored prairies may accelerate restoration, but this has not been evaluated adequately. I transplanted a prairie forb (Liatris pycnostachya) into prepared beds, oldields, and restored prairies. Prepared beds had greater growth and seed production, but survival and flowering was high in oldields and restored prairies. Augmenting restored prairies with locallyapted forbs has promise for accelerating prairie restoration.

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No description available.

Nest survival often is lower at habitat edges than in habitat cores because of greater nest predation and parasitism near edges. I studied nest survival of breeding birds in bottomland hardwood forests of the lower Roanoke River, North Carolina. Nesting success was monitored in two forest width classes: narrow bands of levee forest that were dominated by two edge types, and wide, continuous levee forest stands that have edges but most forest is relatively far from edge. Nest success of Acadian Flycatchers and Prothonotary Warblers was similar in narrow and wide levees; nest success of Northern Cardinals was greater in narrow levees. Results of my study indicate that edge effects are not universal, and that amount of contrast at edges may interact with landscape context to alter ecological processes, such as nest predation. Bird populations are remarkably constant over time relative to other taxa, implying strong regulation. Avian population ecologists, however, have not studied regulatory mechanisms as often as seasonal limiting factors. Conversely, avian behavioral ecologists seldom emphasize the population dynamic consequences of habitat selection and reproductive success. This study describes the intersection of individual behavior and population regulation in the context of a new model of population regulation, site dependence, which is based on characteristics of breeding sites and behavior of individuals. I studied habitat distribution, age structure, reproductive output, and breeding site fidelity of Prothonotary Warblers (Protonotaria citrea) in two different bottomland hardwood forest habitats of the lower Roanoke River in North Carolina. Older males (³ 2 yr old) were equally common in cypress-gum swamps and mixed oak hardwood levee forest. Pairing success and success of first nests indicated that older males occupied the most suitable territories available in each habitat. Bird density was three times greater in swamps, and birds nesting in swamps averaged greater clutch sizes and fledged more young per nest than birds in levees. Greater reproductive output was the result of greater fecundity because nest survival and predation pressure appeared equal in the two habitats. Annual return rates for plot immigrants vs. previous residents did not differ in swamps. In levees, newly arriving birds were less likely to return the following year than previous residents. Immigrants most likely occupied low quality sites and dispersed in an attempt to improve breeding site quality. Habitat-specific demography and density patterns of this study indicate ideal preemptive distribution. Variance in site quality, between and within habitats, and preemptive use of sites are consistent with theory of population regulation via site dependence. Foraging behavior often reflects food availability. For example, in habitats where food availability is high, predators should move more slowly and attack prey more often than in habitats where food availability is low. I studied the foraging behavior of breeding Prothonotary Warblers in two habitat types to assess relative food availability and implications for habitat quality. The two habitats, levee and swamp forest, differ in hydrology, forest structure, and tree species composition. I quantified foraging behavior with focal animal sampling and continuous recording during foraging bouts. I measured two aspects of foraging behavior: 1) prey attacks per minute, using four attack types (glean, sally, hover, strike), and 2) number of movements per minute (foraging speed), using three types of movement (hop, short flight [£ 1 m], long flight [>1 m]). Male warblers made significantly more prey attacks per minute in swamp forest than in levee forest; the same trend was evident in females. Foraging speed, however, was not different between habitats for males or females. Results indicate that foraging effort is similar in swamps and levees, but that warblers encounter more prey in swamps. Greater food availability may be related to greater reproductive success of warblers nesting in cypress-gum swamps than in coastal plain levee forest. / Ph. D.

Os incêndios estão entre as principais causas da perda de diversidade em florestas tropicais e aparentemente seus impactos são ainda mais intensos em áreas de floresta sob efeito de borda. Com o objetivo de quantificar os danos causados pelo fogo sobre o ecossistema e verificar se a dimensão dos danos e a resiliência do ecossistema estão correlacionados com a distância da borda, foram analisados o banco de sementes e a comunidade vegetal em um trecho de floresta estacional semidecidual, na estação ecológica dos Caetetus, Gália, SP. A área experimental compreende dois setores: a floresta queimada, alvo de incêndio acidental e a floresta não queimada adjacente, utilizada como controle. Cada setor foi subdividido em duas faixas de distância da borda da floresta: 0-20 m e 20-50 m. Para o estudo do banco de sementes foram coletadas amostras nas quatro situações de amostragem, cinco dias após o fogo. Para avaliação dos impactos do incêndio sobre a comunidade vegetal e monitoramento da regeneração dos estratos arbóreo e regenerante na área queimada, foram amostrados cinco transectos de 10 x 50 m sentido borda - interior, avaliados aos seis, 15 e 24 meses após a passagem do fogo. O mesmo desenho amostral foi utilizado na área não queimada, em um único levantamento. Visando verificar se a eliminação de gramíneas invasoras e lianas facilitaria a regeneração da comunidade arbórea, foram instalados cinco transectos adicionais de 10 x 20 m, perpendiculares à borda, nos quais foram efetuadas quatro operações de retirada de lianas e capins, em um período de 24 meses. No banco de sementes, tanto a densidade quanto o número de espécies foram consideravelmente inferiores na área queimada (97 sementes.m-2, de 26 espécies) em comparação com a área não queimada (257 sementes.m2, de 40 espécies). A avaliação dos impactos na estrutura da floresta revelou que o fogo foi mais intenso na faixa mais externa da borda, em que houve perda de 100% da biomassa arbórea, enquanto na faixa mais interna a perda foi de 89%. Em comparação com a floresta não queimada, a comunidade vegetal na área atingida pelo fogo apresentou 43 espécies a menos aos seis meses, diferença que diminuiu para 14 espécies aos 24 meses. A resiliência, analisada com base na recuperação da biomassa arbórea, é maior na faixa mais interna, devido às espécies pioneiras oriundas de sementes que se desenvolvem rapidamente. A rebrota de árvores atingidas pelo fogo também é maior na faixa mais distante da borda e contribuiu significativamente na recuperação da riqueza. O controle de gramíneas e cipós apresentou efeito benéfico exclusivamente para o estrato arbóreo e apenas na faixa de 0-10 m de distância da borda da floresta, proporcionando aumento de área basal, densidade total de plantas e cobertura de copas. Os resultados das operações de manejo indicam que técnicas complementares devem ser aplicadas, visando à facilitação da restauração da floresta após o incêndio. O fogo mostrou-se como elemento de degradação, desde o banco de sementes até o estrato arbóreo. Ainda que a floresta tenha recuperado parte de sua riqueza em dois anos, este processo é lento, caracterizando baixa resiliência, especialmente na faixa mais externa da floresta onde o fogo é ameaça permanente. / Fire is one of the main factors causing biodiversity losses in tropical forests and such losses are reported to be still more intense in forest edges. With the aim of quantifying the damages by fire on the seasonal semideciduous forest, and verifying weather their extension and the ecosystem resilience are correlated to the border distance or not, we analyzed both the seed bank and the plant community after fire in the forest edge of Caetetus ecological station (Gália, São Paulo state, Brazil). The experimental area comprised two sectors: 1) burned area (after an incidental fire in October 2003), and 2) unburned neighboring area (control). Every sector was divided in two strips, according to the distance from the edge: 0-20 m and 20-50 m. The soil seed bank was surveyed in the four situations described, five days after fire. Plant community structure and regeneration were assessed in five permanent transections (10 x 50 m), instaled from the edge to the interior, where plant individuals were measured and identified, at six, 15, 18 and 24 months after fire. The same design was repeated once in the unburned area, for comparison. Additionally, with the aim of verifying the hypothesis that arboreal community regeneration after fire could be improved by controlling lianas and invasive grasses, five managed transections (10 x 20 m each) were installed, perpendicular to the edge, where grasses and lianas were eliminated four times within a 24 months period. Fire effects on the ecosystem were remarkable. Richness and density of the seed bank after fire (97 seeds.m-2, 26 species) were considerably lower than in the neighboring unburned forest (257 seeds.m-2, 40 species), the difference being still larger close to the edge (0-20 m). Forest structure was totally changed, 100% of the arboreal biomass lost in the external strip (0-20 m) and 89% lost in the internal strip (20-50 m). Six months after fire the burned area had 43 species, less than the unburned forest. Richness has been slowly recovered and, 24 months after fire, that difference had decreased to 14 species. Resilience, analyzed in terms of biomass recovery, is higher in the internal strip (20-50 m from the edge), where pioneer species quickly regenerate from seeds. Sprouting, which has also been more effective in the internal strip, has equally contributed to the richness recovery. Eliminating grasses and lianas favored only arboreal species in the external strip (0-10 m) where their density, basal area and crown cover were slightly higher than in the unmanaged plots. We consider that this technique, alone, can not be recommended to improve the forest restoration after fire. Fire was, though, a very strong degrading agent in the studied forest, almost completely destroying the arboreal biomass, besides the remarkable reduction in species richness in the seed bank and in the arboreal layer as well. Even though the forest richness and biodiversity have been recovered, that has been a very slow process (low resilience) specially close to the forest edge, where fire is a permanent threat.

Bruce Peninsula National Park (BPNP) clears a 2 m swath of trees on the boundary in order to make it clear when one is entering the park from any neighbouring land; this in particular aims to protect the park and its inhabitants from illegal actions such as hunting and logging. This study looks at the ecological effects of this practice by measuring various microclimate variables and the abundance of eastern redback salamanders (Plethodon cinereus) on the boundary and comparing these measurements to parallel transects at 5, 10, 15, 20, and 40 m. Because it is a small linear development, it is then compared to other types of linear developments, such as roads, trails, and pipelines. The microclimate variables of air temperature, slug abundance, canopy cover, soil pH, total cover area, litter depth, and relative humidity were all significantly affected (p<0.05) up to 10 m into the adjacent forest, indicating that the cleared boundaries do change the surrounding microclimate. Soil pH, downed woody cover area, litter depth, and canopy cover were significantly affected (p<0.05) up to 5 m away from the boundary. Sixty hectares, or 0.4%, of the land area of BPNP is thus affected by the microclimate changes caused by the cleared boundary. These effects are similar to those found for other narrow, vegetated linear developments such as trails. Over double the number of salamanders were found on the boundary as compared to in the forest; this is due to higher cover area availability on the cleared boundary from the felled trees. Therefore, the boundary does not act as a barrier to eastern redback salamander movement, nor does it fragment the local population. Salamander abundance was best explained by the amount of cover area, snail abundance, and the dominant type of vegetation present along transects. It was also found in an additional study that salamander abundance tended to increase with increasing days since the last precipitation event, contrary to most woodland salamander monitoring protocols and methods. The boundaries were seen also to be used by hunters and recreationalists through incidental observations of human disturbance. This increased access to remote areas of the park through use of the cleared boundaries is an issue that requires further study, as the boundary itself may be leading to an increase in illegal activity. Recommendations to BPNP include leaving downed woody cover on the boundary, minimizing the boundary width, reducing lines of sight, decreasing accessibility, increasing landowner and park staff education, communicating with adjacent landowners, and securing funding to complete and maintain the boundary clearing.

Bruce Peninsula National Park (BPNP) clears a 2 m swath of trees on the boundary in order to make it clear when one is entering the park from any neighbouring land; this in particular aims to protect the park and its inhabitants from illegal actions such as hunting and logging. This study looks at the ecological effects of this practice by measuring various microclimate variables and the abundance of eastern redback salamanders (Plethodon cinereus) on the boundary and comparing these measurements to parallel transects at 5, 10, 15, 20, and 40 m. Because it is a small linear development, it is then compared to other types of linear developments, such as roads, trails, and pipelines. The microclimate variables of air temperature, slug abundance, canopy cover, soil pH, total cover area, litter depth, and relative humidity were all significantly affected (p<0.05) up to 10 m into the adjacent forest, indicating that the cleared boundaries do change the surrounding microclimate. Soil pH, downed woody cover area, litter depth, and canopy cover were significantly affected (p<0.05) up to 5 m away from the boundary. Sixty hectares, or 0.4%, of the land area of BPNP is thus affected by the microclimate changes caused by the cleared boundary. These effects are similar to those found for other narrow, vegetated linear developments such as trails. Over double the number of salamanders were found on the boundary as compared to in the forest; this is due to higher cover area availability on the cleared boundary from the felled trees. Therefore, the boundary does not act as a barrier to eastern redback salamander movement, nor does it fragment the local population. Salamander abundance was best explained by the amount of cover area, snail abundance, and the dominant type of vegetation present along transects. It was also found in an additional study that salamander abundance tended to increase with increasing days since the last precipitation event, contrary to most woodland salamander monitoring protocols and methods. The boundaries were seen also to be used by hunters and recreationalists through incidental observations of human disturbance. This increased access to remote areas of the park through use of the cleared boundaries is an issue that requires further study, as the boundary itself may be leading to an increase in illegal activity. Recommendations to BPNP include leaving downed woody cover on the boundary, minimizing the boundary width, reducing lines of sight, decreasing accessibility, increasing landowner and park staff education, communicating with adjacent landowners, and securing funding to complete and maintain the boundary clearing.

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Red Lapacho is timber species with largest market value, considered along with Mahogany, as 'green gold' in areas of natural forest logging. Therefore, the objective of this study was to analyze the different factors that influence the growth of this species, taking into consideration the spatial and temporal dependence inherent to the data. A census of Red Lapacho individuals was carried out in a natural fragment of Subtropical Deciduous Forest with approximately 13 hectares of area. Quantitative morphological and diameter increment data were obtained for each tree of this species. Competitors defined by Bitterlich plots were measured and identified, and a regular grid with infill points of soil sampling were also analyzed. Spatial patterns of distribution of Red Lapacho and its dimensions had completely spatial randomness patterns. Sampled species richness from competitors was of 60 species and the competition generated by them had a random spatial pattern as well. A model for the height – diameter relationship using Generalized Additive Mixed Models (GAMM) produced better results when the latent spatial pattern was included in the model. The spatial patterns of nutrient availability were influenced by relief of the area and distance from the edge of the forest and grassland environments. Anionic nutrients were strongly influenced by the spatial dynamics of the two vegetation types while cations were influenced mainly by pedogenesis. The spatio-temporal Bayesian diameter increment model developed for the Red Lapacho trees showed that there was considerable inter – annual variation in tree growth. The spatial variation in tree growth was closely related to the pedogenesis of the area under study, more specifically, lower increments were observed in areas where the soil had signals of water influence in tits formation. Using site proxies based on geocentric, phytocentric and dendrocentric approaches was able to take into consideration the spatial variation in the growth of Red Lapacho trees and, all approaches may be utilized in the development of growth models. / O Ipê – Roxo é uma das espécies de madeira com maior valor de mercado, sendo considerado, juntamente com o Mogno, o 'ouro verde' em áreas de exploração de florestas naturais. Assim sendo, o objetivo deste estudo foi analisar os diferentes fatores que influem no crescimento desta espécie, levando em consideração a dependência espacial e temporal inerente aos dados. Foi realizado um censo dos indivíduos de Ipê – Roxo em um fragmento natural de Floresta Estacional Decidual com aproximadamente 13 hectares. Foram levantados dados morfométricos e de incremento em diâmetro de cada uma das árvores desta espécie. Os competidores definidos por parcelas de Bitterlich foram medidos e identificados e, uma grade regular com pontos de preenchimento para amostras de solo foram avaliados. Os padrões espaciais de distribuição das árvores de Ipê – Roxo e suas dimensões se adequaram à completa aleatoriedade espacial. A riqueza de espécies amostradas como competidores foi de 60 espécies e a competição por estas gerada também teve padrão espacial aleatório. A modelagem da relação hipsométrica das árvores utilizando Generalized Additive Mixed Models (GAMM) obteve melhor ajuste quando o padrão espacial latente foi incluso no modelo. Os padrões espaciais de disponibilidade dos nutrientes foram afetados pelo relevo da área e pela distância da borda dos ambientes florestal e campestre. Nutrientes aniônicos foram fortemente influenciados pela dinâmica espacial entre os dois tipos vegetais enquanto cátions foram influenciados principalmente pelo processo pedogênico. O modelo espaço – temporal Bayesiano de incremento em diâmetro desenvolvido para as árvores de Ipê – Roxo mostrou que existe considerável variação inter - anual do crescimento. A variação espacial do crescimento também se mostrou relacionada com o processo pedogênico da área sob estudo, sendo que menores incrementos foram observados em áreas onde o solo apresentou sinais de hidromorfismo. A utilização de estimadores de sítio baseados em índices geocêntricos, fitocêntricos e dendrocêntricos foi capaz de levar em consideração a variação espacial do crescimento de árvores de Ipê – Roxo e, todos podem ser utilizados para a construção de modelos de crescimento.

Made available in DSpace on 2014-06-11T19:23:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-05Bitstream added on 2014-06-13T20:10:29Z : No. of bitstreams: 1 athayde_ea_me_rcla.pdf: 528033 bytes, checksum: 848db7d697c39eb44d6a5d5fe7d6cbcc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O isolamento espacial causado pela fragmentação florestal e o isolamento temporal causado pela assincronia da floração das plantas têm sido propostos como importantes fatores afetando a reprodução de populações vegetais. Nós determinamos os efeitos da fragmentação florestal e isolamento espacial na fenologia reprodutiva e vegetativa e no sucesso reprodutivo de Anadenanthera falcata (Benth.) Speg. em uma região de cerrado stricto sensu em Itirapina, São Paulo. Para isso, nós comparamos populações em três diferentes ambientes: (1) árvores circundadas por pastagem, ou seja, isoladas; (2) árvores presentes na borda; e (3) árvores presentes no interior. Nós acompanhamos diferentes variáveis da população como: duração, freqüência, época e sincronia da floração, época da frutificação, do brotamento e da queda foliar, produção de flores e frutos, número de flores que se convertem em frutos, número de sementes por fruto, proporção de sementes predadas por fruto e número de plântulas. A duração e a freqüência da floração foram duas vezes maiores em indivíduos isolados. Nós encontramos diferenças na época de floração e frutificação entre os ambientes, assim como na proporção de indivíduos que floresceram e frutificaram, que foi maior no isolamento. A produção de flores e frutos foi maior nas plantas isoladas, no entanto, o sucesso reprodutivo não diferiu entre os ambientes, com o número de flores que se convertem em frutos e o número sementes por fruto semelhante entre eles. A proporção de sementes predadas por fruto foi menor nos indivíduos em isolamento. O número de plântulas diferiu entre os ambientes, com a pastagem não apresentando plântulas de A. falcata. Nós argumentamos que a falta de competição... / Spatial isolation caused by forest fragmentation and temporal isolation caused by asynchronous flowering of plants have been proposed as important factors that affect the reproduction of plant populations. We determined the effects of forest fragmentation and spatial isolation on phenology patterns and reproductive success of the tropical dry forest Anadenanthera falcata (Benth.) Speg. in a region of cerrado stricto sensu in Itirapina, São Paulo. For this, we compared populations in three habitat conditions: (1) trees in habitat surrounded by pasture, or isolated; (2) trees in anthropogenic edges; and (3) trees in the interior of the cerrado. We followed different variables of the population as: duration, frequency, time and synchrony of flowering, time of fruiting, time of leaf flushing and leaf fall, total flower production, total fruit production, the fruit set, the seed set, the predation of seed and the number of seedlings. The duration and the frequency of flowering were greater in the individuals in pasture. We also found little overlap in time flowering and fruiting among individuals in pasture, anthropogenic edge and interior. The total flower production and total fruit production were greater in the individuals in pasture. No have differed in fruit set nor on seed set among habitats. The proportion of predation seeds differed among the habitats with the isolated individuals presenting smaller damages for insects predators in their seeds. The number of seedlings differed among the habitats with the pasture not presenting seedlings of A. falcata. We argued that the competition lack and the resources availability for the plants in isolation are the responsible for the largest duration and frequency of the flowering, as well as for the... (Complete abstract click electronic access below)