<p> The Luquillo Forest Dynamics Plot (LFDP) has played a critical role in the initial discovery and subsequent investigation of many processes that govern tropical island wet forest dynamics. Previous work has identified past land use as the main factor in creating forest community compositional and structural differences across the plot. The responses of different species to past land-use intensity and to hurricane disturbances have created an evolving forest mosaic ideal for studying tropical forest successional dynamics. I revisited the interaction of land-use legacies and natural disturbance in the LFDP with new data and new approaches, with the motivation to reveal new information about the relative roles of anthropogenic disturbance and environmental-niche partitioning on tropical plant communities over time. </p><p> In the context of tropical forests and their successional dynamics, I asked how succession resulting from a history of human land use and more recent hurricanes interacts with background environmental variation to effect community structure and diversity. Community dynamics, in terms of forest structure and composition, were summarized over a twenty-one year period, noticing a decreasing trend in species richness over time and structural maturation of the forest, shown by a decline in small stems (trees &lt; 10 cm diameter) as it recovered from the compound effect of two major hurricane disturbances &ndash; Hugo, 1989 and Georges, 1998. We evaluate the magnitude of past human land use effects over time and define indicator species for areas of differing land-use pressure within the 16-Ha permanent LFDP. Using redundancy analysis, plant community-environmental relationships with respect to soils and topography are quantified. Spatial variables, computed using a principle coordinates of neighborhood matrix, explained the majority of the variability in plant community composition between areas of high and low past land-use within the LFDP, meaning environmental differences (e.g. niche differentiation among tree species) were found to be secondary to land-use legacies in determining forest community composition. </p><p> Over two decades, the effect of past land-use peaked about 15-years following the first of two hurricanes, and remained relative stable over time. Despite damaging the forest, hurricanes preserved community differences in species composition and reinforced structural asymmetries due primarily to two species; <i> Dacryodes excels</i> Vahl., a dominant primary forest tree species, and <i> Casearia arborea</i> (Rich.) Urb., an abundant secondary forest species. Abiotic environmental factors (e.g. soil resources and topographic variation) were weak at explaining differences in forest community composition. Plant community-environmental relationships were stronger in more anthropogenically-disturbed areas, suggesting long-term effects of land use on tropical forest communities on current community dynamics.</p>

<p> <i>Polylepis</i> forests are a unique high-elevation forests dominated by trees of the <i>Polylepis</i> (Rosaceae) genus found only in South America. These forests are distinctive not only for growing at some of the highest elevations in the world, but because they are distributed as isolated forest islands inside a landscape otherwise dominated by grasses. This distribution is due in part to human disturbance on the landscape and there is interest in restoring cover of <i>Polylepis</i>. Understanding of regeneration dynamics and seedling ecology of <i>Polylepis</i> can help in the management of forests and the restoration of this forest cover, but there are important gaps in knowledge regarding theses aspects in most species. For the expansion of forest cover into current grassland areas, it is important to understand the ability of seedlings to colonize, survive and grow in these areas and identify important biotic and abiotic barriers to this. In this dissertation, I contribute to our understanding of these ecological aspects for two species of <i>Polylepis</i> (<i>P. sericea </i> and <i>P. weberbaueri</i>) using a series observational studies and manipulative experiments in forests found between 4000&ndash;4500 masl in Huascaran National Park (Ancash, Peru). </p><p> In Chapter 1, I surveyed patterns of seedling dispersion across forest-grassland boundaries along the elevational gradient and identified significant associations of seedling densities to environmental covariates at local and landscape scales. I found that seedling densities of both species decrease drastically at the edge of the forest canopy, and few seedlings are found in the grassland even within meters of the forest, suggesting significant barriers to seedling establishment in the grassland. Additionally, seedling densities of each species showed patterns with elevation and solar irradiation that mirrored those of adult distributions on the landscape and were different from each other, suggesting that each species has unique environmental tolerances that manifest in the seedling stage and are important to consider in their management and restoration. </p><p> In Chapter 2, I used a series of livestock exclusion experiments to examine the influence of domestic livestock on natural regeneration inside and outside the forest and test the hypothesis that livestock are a significant barrier to seedling establishment at forest-grassland edges. After one year of livestock exclusion, I found only partial support for this hypothesis. In <i>P. sericea</i> forest stands, seedling densities increased, and recruitment and seedling growth was higher in fenced grassland areas. However, in <i> P. weberbaueri</i> stands there was little change in juvenile densities and no differences in seedling performance, except that recruitment was lower in fenced forests areas compared to unfenced forest. This showed that the influences of livestock on <i>Polylepis</i> seedling may be different depending on the habitat and species of <i>Polylepis</i>. Additionally, we found that seedling survival was surprisingly high, and similar between forest and grassland habitat. </p><p> In Chapter 3, I used sowing and &ldquo;wildling&rdquo; transplant experiments within the previous exclosure experiments to tease apart early ontogenetic filters to seedling establishment in the grassland compared to the forest. I found that the seedling emergence stage is a strong bottleneck for seedling establishment in the grassland. Furthermore, I found that <i>P. weberbueri </i> seedling density inside the forest appears to be seed limited, and can be increased by sowing. Transplanted seedlings survival was lower than found previously for natural seedlings, but was also similar between both habitats. However, it appears that livestock depresses <i>P. sericea </i> transplant survival inside the forest. Only <i>P. weberbueri </i> seedlings showed differences in growth between habitats, declining in height in the grassland, but there was only evidence that livestock suppressed growth. I concluded that seedling transplant will be the most efficient way to increase seedlings in the grassland for restoration. </p><p> Together, the results of this dissertation suggest that both unassisted and assisted expansion of natural <i>Polylepis</i> forests faces significant barriers, in particular low seedling emergence in grassland is a strong bottleneck to establishment in this habitat. It remains unclear whether livestock are generally a barrier to forest expansion, as their effects appear to be specific to each species of <i>Polylepis</i>. Here, <i> P. sericea</i> appears to be more sensitive in both forest and grassland to livestock activity than <i>P. weberbaueri</i>, but future work should address longer-term effects of livestock exclusion to confirm the population trajectories observed after one year. Finally, wilding transplants of these species can be used in restoration to overcome the barrier emergence poses to <i>Polylepis</i> establishment in grassland, although with further research, seeding schemes may prove a viable strategy</p><p>

Pitch pine-scrub oak communities, commonly called pine barrens, are scattered throughout the northeastern United States and are severely threatened by development and fire suppression. The pine barrens of Plymouth and Barnstable Counties in southeastern Massachusetts together comprise the third largest area of this imperiled natural community remaining in North America. The region is also experiencing extremely rapid human population growth making it necessary to set realistic, local-scale conservation priorities. I used the pine barrens of southeastern Massachusetts as a case study for addressing a variety of issues of central importance for local-level conservation planning. To address these questions, I conducted both community and individual species analyses of bird and moth survey data collected at the Camp Edwards Training Site in Barnstable County. First, I examined the relative impact of plot, patch, and landscape factors on the distribution and abundance of the breeding bird and rare moth communities of Camp Edwards. I used partial canonical correspondence analysis to decompose the variance explained by each of these levels of environmental factors. For the bird community as a whole, landscape factors explained slightly more variance than plot factors, and patch factors were nonsignificant. Examination of individual bird species of conservation concern revealed that the distributions of the majority of these species were best explained by the landscape model. In the rare moth community, landscape factors explained more than twice as much variance as plot or patch factors, and the presence of host plants was significant only at the landscape level. The specific variables with the greatest influence on community structure are discussed. I then used logistic regression to develop individual species models for birds and moths of conservation concern based on patch and multi-scale landscape variables. I used these models to predict bird and moth rarity hotspots in southeastern Plymouth County. Results indicated (1) there was little congruence between bird and moth rarity hotspots; (2) the few overlapping hotspots occurred in and around Myles Standish State Forest; and (3) most hotspots were inadequately protected. The results suggest that multi-taxa, multi-scale approaches may be required for comprehensive conservation planning in pine barrens communities.

In Massachusetts both human and beaver population levels are rising, beaver damage complaints are escalating, and beaver management options are restricted by the 1996 Wildlife Protection Act. Employing the Cognitive Value Hierarchy, this study enhances understanding of the public's value orientations, attitudes, and norms regarding human-beaver conflicts in Massachusetts. A mailback questionnaire was sent to a random sample of 5,563 residents in three geographic regions in Massachusetts and to residents who submitted a beaver complaint to MassWildlife in 1999/2000 (47.3% overall response rate). Results indicate that respondents believe beaver are an important part of the natural environment and they have a right to exist. Respondents also support some form of beaver management. Most respondents believe that beaver-related damage in Massachusetts has either increased or remained the same over the past five years, and indicated a preference for fewer beaver, regardless of experience with beaver damage. Respondents' attitudes are influenced by their experience with beaver damage, perceptions of extent of beaver damage, and tolerance of beaver. As severity of beaver damage was perceived to increase, respondents were more willing to accept lethal management/control of beaver. Respondents characterized by a “wildlife-use” orientation expressed a greater willingness to accept lethal action in response to beaver activity than respondents characterized by a “wildlife-protection” orientation. This relationship was partially mediated when respondents believed beaver damage had increased and/or they preferred to see fewer beaver in Massachusetts. Value orientations proved to be predictive of both attitudes and norms, thus validating the propositions of the Cognitive Value Hierarchy. Results confirm the importance of understanding and monitoring public attitudes, norms, perceptions, and tolerance in a longitudinal framework and coupling this information with biological data to determine trends in relation to increases in beaver populations and human-beaver conflicts. The concepts and causal relationships posed by the Cognitive Value Hierarchy can provide information to link attitudes, norms, and values of wildlife stakeholder groups with socially acceptable management strategies. Replicating, expanding, and applying this framework to other wildlife species, and in different socio-political environments, can enhance the effectiveness and applicability of this theoretical perspective in understanding and resolving complex human-wildlife conflicts.

Lymantria mathura Moore is a polyphagous defoliator of hardwood trees in the Russian Far East, Japan, India, and China. Its egg masses were intercepted on ships arriving to Pacific Northwest. If introduced and established in North America, L. mathura is likely to cause serious economic consequences. As a part of a program for development of monitoring and control measures, possible host range, larval air-borne dispersal, mating behavior, and pheromone communication of L. mathura were studied. Survival and development of first instars of L. mathura were examined on 24 hardwood and conifer tree species from North America, Europe, and Asia. Lymantria mathura performed well on hosts in the family Fagaceae. Survival and growth rate was high in the genus Fagus (beech) and Quercus (oak), particularly white oak group. Performance was intermediate on species of red oak group and species from Juglandaceae, Betulaceae, and Oleaceae. Survival was poor on Pinaceae. Dispersal rates, settling velocities, and diel periodicity of dispersal for both L. mathura and Asian L. dispar were studied to predict probable extent of neonate dispersal. Dispersal rates for L. mathura exceeded those of Asian and North American gypsy moths. Neonates of L. mathura weighed less and had slower settling velocities than Asian or North American gypsy moths. Pheromone-baited traps would be important for detecting introductions of L. mathura, but a sex pheromone has not yet been identified. I studied the olfactory reaction of males to females and to odor compounds in the wind tunnel. Number of males performing searching flight in a pheromone plume was lower than moths performing non-pheromone mediated flight. There was no difference in male performance when stimulated with preparations of female abdominal tip extracts or synthetic compounds derived from females. Studies of courtship showed that females initiated calling shortly after start of scotophase, and courtship occurred several hours later. Mating occurred after a calling female starts wing fanning, initiating a fanning response and flight in a nearby male. A receptive female lifts the wings and allows a male underneath. During behavioral studies, low frequency atonal sound associated with wing fanning was recorded in both sexes of L. mathura, and several other lymantriids tested for comparison. There were differences in wing beat frequencies between sexes and species.

Mercury and polychlorinated biphenyl (PCB) residues in livers of trapper harvested river otters from Massachusetts were evaluated. Two-hundred and ten river otters collected during 1986 and 1987 were composited into 103 samples and analyzed. Comparisons among 20 watersheds were made using 96 samples. Mercury residues were detected in all samples and ranged from 0.45 to 4.82 ppm wet weight with an arithmetic mean of 1.93 ppm. PCB residues were detected in all but 3 samples and ranged from none-detected (ND) to 22.00 ppm with a geometric mean of 1.03 ppm wet weight. Lipid-adjusted total PCBs ranged from ND to 6.47 ppm with a geometric mean of 0.36 ppm. Significant differences (P $<$ 0.05) were detected among watersheds for mercury, total PCBs, and lipid-adjusted total PCBs. A significant difference between years was detected for lipid-adjusted total PCBs. Tukey's HSD test indicated the Charles, Blackstone, and Parker watersheds had significantly higher otter liver mercury residues than the Westfield, Quinnebaug, Deerfield, Connecticut, Buzzard's Bay, and North Coastal watersheds. Juvenile otters had significantly (P = 0.007) lower mercury residues than older otters. Tukey's HSD test indicated the Housatonic, Buzzard's Bay, Merrimack, Concord, and Charles watersheds had significantly higher otter liver total PCB residues than 13 of the remaining 15 watersheds sampled. Juvenile otters had significantly (P = 0.02) lower levels of total PCBs than older otters. Correlations between otter residues and whole-body fish residues on a watershed basis showed a strong relationship between fish and otter mercury residues. River otters can be used to assess general background mercury and PCB contamination levels on a watershed basis to prioritize and justify more intensive contaminant monitoring efforts. However, caution in interpreting PCB residue analyses is strongly recommended because of high variances associated with watershed means. River otter populations do not appear to be at risk singly from either mercury or PCB contamination in Massachusetts. Population monitoring should evaluate potential additive or synergistic effects of mercury in combination with PCBs in certain watersheds. Laboratory research is needed to document effect levels of environmental contaminants in river otters.

In order to protect water quality and quantity, a decision support system, Watershed Forest Management Information System (WFMIS), was developed with Visual Basic® and ArcObjects® in ArcGIS® 9. There are three subsystems: the Watershed Management Priority Indices (WMPI) is a zoning method for forest management planning with respect to soils, water, and aquatic ecosystems; the Forest Road Evaluation System (FRES) is a module to evaluate roads and road-stream crossings in order to develop and implement preventive management strategies, and the Harvest Scheduling Review System (HSRS) is a module to estimate the cumulative hydrologic effect of timber harvesting on water yield and associated changes in water quality. The system is an extension to ArcGIS ® 9. It uses commonly available GIS data and has user friendly interfaces to assist foresters and planners to manage the watershed in an environment healthy way.

<p> Erosion is a serious concern across the US and the globe. One effective method to reduce soil erosion is to apply rolled erosion control products (RECPs). One material source for use in RECPs that has not been studied is low-value forest residuals (LVRs). The objectives of this study were to design RECPs out of four LVRs (leaf litter, willow whiplets, willow chips, spruce needles) and to assess their ability to reduce soil loss, control water quality (turbidity and total phosphorous), and enhance germination. LVR RECPs were tested using ASTM standards on bare, detritus, and burned soils. Leaf litter and spruce needle RECPs were highly effective at all three abilities, while the willow whiplet and chip RECPs were effective at reducing erosion, but less effective at controlling water quality and enhancing vegetation. Overall, the use of LVRs as a material source for RECPs shows great promise.</p>

<p> Deforestation in the Congo Basin is altering the natural functioning and services of the ecosystem and adversely impacting highly vulnerable human populations who rely on their proper functioning. There is currently no framework that comprehensively addresses the historical and cultural complexities that are persistent in Central African societies and that also include, from a micro scale, the detailed voices of local communities. Without such a holistic framework, it is difficult to evaluate the effectiveness or harmfulness associated with current management strategies in responding to deforestation at the various levels. This transdisciplinary mixed method study determined the most salient indirect and direct causes of forest loss, the impacts resulting from an altered state, and the effectiveness of current management responses by assessing changes in forest cover, forest provisions, and trends in forest management. Because forests are common goods, the elasticity of forests are dependent on a multitude of human activities and attitudes. Therefore, data collected via survey tools were used to evaluate the role of multiple stakeholders in the state of the Congo Forest using the Driver-Pressure-State-Impact- Response (DPSIR) framework, a structured analytical tool created by the European Environmental Agency for better understanding of Integrated Environmental Assessments. To best explore local to international perspectives on the effectiveness of current strategies in sustaining forests for livelihoods and ecosystem services, research methods included conducting remote sensing analysis of Landsat satellite images, interviewing over 325 individuals living in 25 communities in the Lake T&eacute;l&eacute;-Lake Tumba Landscape of northwestern Democratic Republic of Congo and 20 individuals working on forest management, conservation, and funding, and a climate analysis using 40 years of weather data collected from a scientific reserve located within the landscape. Results highlight that local populations are highly environmentally literate and their knowledge is a useful tool for qualifying environmental changes, such as reduced lake health, animal health, and plant health. Remote sensing results show the forest is in a state of decline and climate findings confirm the ecological health of the landscape has been reduced demonstrated by major shifts in the traditional agricultural calendars and the effects are having adverse public health impacts on local communities. The process of this research itself interfaces science and policy and thus recommendations focus on how to make effective payments to communities for supporting alternative livelihoods in order to prevent deforestation while next steps should focus on the implications of forest loss and the promotion of a One Health approach at the landscape level.</p>

This investigation involved post-colonial (∼85 years old), ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) growing at ∼2,255 m in northern Arizona an area that historically experienced a wildfire event every 5-20 years. Such fires were typically limited to surface fuels and thus seldom effected stand replacement. However, since the settlement of European peoples in approximately the 1880's fire cycles have been dramatically altered by the systematic suppression of all wildland fire. This change greatly increased seedling survivorship, and has resulted in a forest with historically unprecedented stem densities. Under current conditions, with individual trees receiving insufficient nourishment, many ponderosa pine forests have demonstrated stagnated growth and increased risk of pathogenic attack or catastrophic wildfire. In response to deteriorating forest conditions and the building threat of wildfire many forest managers are exploring methods of reestablishing natural cycles to restore historical stand dynamics. Typically this effort has included timber harvesting and/or the use of prescribed fire. In this application timber harvesting typically involves removing the younger cohort of post-settlement trees. While the objectives of prescribed fire are similar to timber harvesting, fire is by its nature less precise; treatment can not be limited to a target demographic. As a result, the application of prescribed fire can lead to different stand conditions than tree removal. It is also common (especially under extreme stem densities) to have a timbering operation precede a fire treatment. The impact of these three scenarios on residual ponderosa pine tree reserves is not well understood. This project has taken part in cooperation with the USDA Forest Service and the national Fire and Fire Surrogate task group. The experiment was arranged with a 2 x 2 factorial design which resulted in four treatments. Plots were either timber harvested, burned with prescribed fire, cut than burned, or left untreated with treatment application occurring in 2002-03, three years prior to initial sampling. Trees were sampled with one of two methods. Initially a randomly selected coarse lateral root was mechanically exposed for three meters; roughly the average canopy drip line radius whereupon root tissue was extracted at intervals starting at the root collar. This disruptive method was eventually replaced by limiting sampling to the root collar. To slow metabolic activity root tissue samples were field chilled before being oven dried. Dried samples were ground through a 40# mesh and then triple-extracted with ethanol for carbohydrate quantification with high performance liquid chromatography (HPLC). Carbohydrate samples were processed at the University of Massachusetts Cranberry Experiment Station in Wareham MA. with an ion exchange column and a refractive index detector using water as a mobile phase. Starch quantifications were conducted on sub-samples by Cumberland Valley Analytical Services INC. (Maugansville, MD.) using an alpha-amylase digestion and color metric evaluation on an Astoria auto analyzer. As a result of this project it was determined that the ponderosa pine root non-structural carbohydrate components are sucrose, glucose, fructose, xylose and starch. Reserve concentrations of soluble (EtOH) carbohydrates declined significantly between May and August on plots that were not treated with prescribed fire, burning eliminated this seasonal difference. Starch and total non-structural carbohydrates were also found to be lower in August (compared to May) suggesting that during the summer (May–August), ponderosa pine must draw upon reserves. It was also found that carbohydrate concentrations increased significantly with distance from the root collar. When sampled on a monthly basis it was determined that carbohydrates, both individually and collectively, were significantly affected by the month of sampling and that overall timber harvesting reduced total soluble (EtOH) sugar concentrations. It is believed that collectively carbohydrate concentrations were a reflection of the bi-modal precipitation pattern of northern Arizona; spring snow-melt in particular, appears to have significant increased stored reserves. Key Words: Pinus ponderosa, prescribed fire, restoration, Southwest, thinning