The removal of indigenous forest and associated fragmentation of habitats has probably had significant impacts on the diversity of stream communities in New Zealand. In this study I investigated the effects of forest fragmentation on stream invertebrate communities on Banks Peninsula. Six catchments were investigated, three with continuous indigenous forest in the riparian zone and three with fragmented indigenous riparian forest. An extensive benthic survey was conducted at three sites in each river catchment, one downstream on the mainstem of the river and two sites in different headwater tributaries. Adult sampling, consisting of malaise and sticky trapping, was also conducted at a sub-set of sites. Taxonomic richness of both the benthic and adult communities was significantly higher in continuous forest than in fragmented forest, and the composition of benthic communities also differed between continuous and forest fragments. Furthermore, benthic invertebrate densities were higher in fragments than continuous forest sites. The fragments in the headwaters were more likely to support forest specialist taxa (e.g. the stonefly Zelandobius wardi, and the caddisfly Costachorema peninsulae), than the downstream fragments. My results indicate that forest fragmentation has resulted in marked changes in benthic communities on Banks Peninsula, and that location of the fragment within the catchment also is important in influencing the diversity and composition of benthic communities. The maintenance of indigenous forest in the headwaters of streams may be essential for the persistence of endemic and forest specialist taxa on Banks Peninsula.

The removal of indigenous forest and associated fragmentation of habitats has probably had significant impacts on the diversity of stream communities in New Zealand. In this study I investigated the effects of forest fragmentation on stream invertebrate communities on Banks Peninsula. Six catchments were investigated, three with continuous indigenous forest in the riparian zone and three with fragmented indigenous riparian forest. An extensive benthic survey was conducted at three sites in each river catchment, one downstream on the mainstem of the river and two sites in different headwater tributaries. Adult sampling, consisting of malaise and sticky trapping, was also conducted at a sub-set of sites. Taxonomic richness of both the benthic and adult communities was significantly higher in continuous forest than in fragmented forest, and the composition of benthic communities also differed between continuous and forest fragments. Furthermore, benthic invertebrate densities were higher in fragments than continuous forest sites. The fragments in the headwaters were more likely to support forest specialist taxa (e.g. the stonefly Zelandobius wardi, and the caddisfly Costachorema peninsulae), than the downstream fragments. My results indicate that forest fragmentation has resulted in marked changes in benthic communities on Banks Peninsula, and that location of the fragment within the catchment also is important in influencing the diversity and composition of benthic communities. The maintenance of indigenous forest in the headwaters of streams may be essential for the persistence of endemic and forest specialist taxa on Banks Peninsula.

The character of Virginia's nonindustrial private forests is changing primarily for two reasons. First, many large, continuous forested tracts are being sub-divided, into with the resulting smaller tracts purchased for amenity values and recreation instead of as a timber investment (Hodge 1993). Second, the demographics of non-industrial private forest (NIPF) landowners are shifting away from an agricultural, rural focus to an urban oriented lifestyle and absentee ownership. These changes may mean less timber available for purchase by the forest industry. Timber that is sold will be on smaller parcels that is bound to have an impact on the procurement activities of forest industries. However, little research has been performed on the impacts of site and landowner characteristic on stumpage prices. The objective of this research project is to identify how the stumpage price of timber is altered by the characteristics associated with the changing forest: decreasing tract size, decreasing harvested volumes, landowner residence, and landowner harvesting preferences. In addition to the price of timber, the competitiveness of timber sales is analyzed to determine what impact the fragmented forest could have on the competitiveness of timber markets. To perform the study, site and landowner information was collected for 138 recent NIPF timber sales that occurred within central Virginia. This region is identified as a critical area for the study of forestry activities because of the growing urban and suburban residential populations and the large amount of forest industry activities taking place there. Results show that access to the site is the most important characteristic determining the selling price of timber. Sites that are easy for logging crews and vehicles to approach dramatically increase the price paid per ton. Tract size is less important in determining bid prices for timber either once the total volume harvested passes a minimum of 500 tons, or there is mature hardwood sawtimber on the site and the acreage is greater than 50 acres. Landowners preference for select cut harvests results in a lower price per ton being paid by the purchaser due to the increased logging costs associated with this type of harvesting. / Master of Science

Historically, New Zealand was almost completely forested below the alpine treeline, but 1000 years of Polynesian and European colonisation has resulted in the destruction of nearly three-quarters of the original forest cover. I assessed historical patterns of deforestation and forest fragmentation in relation to all major topographical, climatic and anthropogenic variables that may drive forest loss. Much of the deforestation occurred in regions with drier climates, reflecting the fact that human population density has always been highest in areas with moderately dry climates and that dry forests burned much more readily and extensively. The large remaining tracts of forest are mainly restricted to high elevations, while the lowland forests have been fragmented into small, isolated remnants. Fragmentation of the surviving forests increases their susceptibility to edge effects and invasion by adventive species, indelibly altering the ecological communities they support. Although a large proportion of the remaining forest is owned or managed by the Department of Conservation, the distribution of that protection is greatly skewed towards areas of low economic value and is not representative of the relative conservation value of landscapes that differ in their environments and degree of forest cover. Forest cover in the majority of New Zealand landscapes has been reduced below the level of an expected extinction threshold of 30 % forest cover in the landscape, and ongoing deforestation threatens to force more landscapes below the critical threshold. Deforestation is still occurring across the country, and it is concerning that current deforestation rates in some areas are far greater than those observed in tropical, developing nations. I showed that the remaining forest fragments in New Zealand have complex, irregular shapes, and find ubiquitous evidence that core habitats within individual fragments are spatially discontinuous, comprising multiple, disjunct cores of small average area. Because population density of forest-interior species typically decreases with decreasing habitat area, multiple, disjunct cores support a lower total population size than a single, discrete core of the same total area. I found in a spatially explicit, landscape-level analysis of habitat fragmentation in New Zealand that simple core-area models consistently overestimate the carrying capacity of habitat fragments. Habitat fragmentation and habitat destruction are widely recognised as two of the leading threats to the continued maintenance of global biodiversity. The effects of habitat fragmentation on biodiversity fall into five categories that describe the spatial and landscape attributes of fragmented ecosystems; (1) fragment area, (2) edge effects, (3) fragment shape, (4) fragment isolation, and (5) matrix structure. Each attribute affects species individually according to their particular biological requirements and life history strategies, leading to complex, and often conflicting, sets of results in the empirical literature. Furthermore, it is now apparent that the effects of fragmentation can take many decades to become apparent and that the spatial arrangement of habitat fragments can interact with other ecological processes to magnify the detrimental impacts of fragmentation on species. I synthesised the published effects of habitat fragmentation on the morphology, distribution and abundance of invertebrate populations, species and communities, and present examples of time lags and synergies from the fragmentation literature. I explicitly considered the underlying mechanisms determining the responses ofindividuals to fragmentation and discussed the role of species traits in determining species vulnerability to changes in the spatial attributes of fragmented landscapes. I sampled 35,461 beetles from a fragmented forest and matrix system in New Zealand over very large gradients of fragment area (10-2 to 106 ha) and edge distances (up to 1,024 m from the forest edge into both the forest and the adjacent matrix interiors). The beetle fauna was very diverse, with 893 species identified in 65 families, representing nearly 20 % of the known species in New Zealand. Beetle communities were strongly structured by forest fragmentation, but in species-specific ways. Distance to edge was consistently shown to have the largest effect on community composition, but, surprisingly, an interaction between area and distance to edge had a stronger impact on community structure than fragment area alone. I developed a new method to partition the variance in community composition that was explained by putative area and edge effects. The method uses backwards stepwise regression to determine significant predictors of gradients in beetle species composition that were identified by canonical ordination. I found that edge effects were driven partially by small-scale alterations to microhabitat and microclimate and partially by changes in landscape composition that varied with distance to edge. In contrast, fragment area effects were driven primarily by edge effects, the strength of which varied significantly with fragment area. I took a novel approach to characterising the responses of 185 common species to habitat edges by modelling species abundances across edges with a general logistic model that described sigmoid trends in abundance for forest specialist and matrix specialist species, as well as unimodal trends in abundance for edge specialist species. I used the second derivatives of the logistic and unimodal models to statistically determine the width of species response zones to edge effects. Beetle species responses to forest edges occurred over far greater scales than previously suspected, with edge response zones for some species extending for more than 1 km. Average edge response zones were 194 m wide and, for many species, began in the forest but extended into the adjacent matrix. Species were categorised according to their responses to fragment area and distance to edge. Closely related species were expected to be placed in similar response categories because they are predicted to share suites of traits that determine their susceptibility or resilience to fragmentation by virtue of common ancestry. Despite many species exhibiting responses that could be grouped into categories, individual species responses to fragmentation were largely idiosyncratic with even closely related species exhibiting strongly contrasting responses to fragmentation.

Historically, New Zealand was almost completely forested below the alpine treeline, but 1000 years of Polynesian and European colonisation has resulted in the destruction of nearly three-quarters of the original forest cover. I assessed historical patterns of deforestation and forest fragmentation in relation to all major topographical, climatic and anthropogenic variables that may drive forest loss. Much of the deforestation occurred in regions with drier climates, reflecting the fact that human population density has always been highest in areas with moderately dry climates and that dry forests burned much more readily and extensively. The large remaining tracts of forest are mainly restricted to high elevations, while the lowland forests have been fragmented into small, isolated remnants. Fragmentation of the surviving forests increases their susceptibility to edge effects and invasion by adventive species, indelibly altering the ecological communities they support. Although a large proportion of the remaining forest is owned or managed by the Department of Conservation, the distribution of that protection is greatly skewed towards areas of low economic value and is not representative of the relative conservation value of landscapes that differ in their environments and degree of forest cover. Forest cover in the majority of New Zealand landscapes has been reduced below the level of an expected extinction threshold of 30 % forest cover in the landscape, and ongoing deforestation threatens to force more landscapes below the critical threshold. Deforestation is still occurring across the country, and it is concerning that current deforestation rates in some areas are far greater than those observed in tropical, developing nations. I showed that the remaining forest fragments in New Zealand have complex, irregular shapes, and find ubiquitous evidence that core habitats within individual fragments are spatially discontinuous, comprising multiple, disjunct cores of small average area. Because population density of forest-interior species typically decreases with decreasing habitat area, multiple, disjunct cores support a lower total population size than a single, discrete core of the same total area. I found in a spatially explicit, landscape-level analysis of habitat fragmentation in New Zealand that simple core-area models consistently overestimate the carrying capacity of habitat fragments. Habitat fragmentation and habitat destruction are widely recognised as two of the leading threats to the continued maintenance of global biodiversity. The effects of habitat fragmentation on biodiversity fall into five categories that describe the spatial and landscape attributes of fragmented ecosystems; (1) fragment area, (2) edge effects, (3) fragment shape, (4) fragment isolation, and (5) matrix structure. Each attribute affects species individually according to their particular biological requirements and life history strategies, leading to complex, and often conflicting, sets of results in the empirical literature. Furthermore, it is now apparent that the effects of fragmentation can take many decades to become apparent and that the spatial arrangement of habitat fragments can interact with other ecological processes to magnify the detrimental impacts of fragmentation on species. I synthesised the published effects of habitat fragmentation on the morphology, distribution and abundance of invertebrate populations, species and communities, and present examples of time lags and synergies from the fragmentation literature. I explicitly considered the underlying mechanisms determining the responses ofindividuals to fragmentation and discussed the role of species traits in determining species vulnerability to changes in the spatial attributes of fragmented landscapes. I sampled 35,461 beetles from a fragmented forest and matrix system in New Zealand over very large gradients of fragment area (10-2 to 106 ha) and edge distances (up to 1,024 m from the forest edge into both the forest and the adjacent matrix interiors). The beetle fauna was very diverse, with 893 species identified in 65 families, representing nearly 20 % of the known species in New Zealand. Beetle communities were strongly structured by forest fragmentation, but in species-specific ways. Distance to edge was consistently shown to have the largest effect on community composition, but, surprisingly, an interaction between area and distance to edge had a stronger impact on community structure than fragment area alone. I developed a new method to partition the variance in community composition that was explained by putative area and edge effects. The method uses backwards stepwise regression to determine significant predictors of gradients in beetle species composition that were identified by canonical ordination. I found that edge effects were driven partially by small-scale alterations to microhabitat and microclimate and partially by changes in landscape composition that varied with distance to edge. In contrast, fragment area effects were driven primarily by edge effects, the strength of which varied significantly with fragment area. I took a novel approach to characterising the responses of 185 common species to habitat edges by modelling species abundances across edges with a general logistic model that described sigmoid trends in abundance for forest specialist and matrix specialist species, as well as unimodal trends in abundance for edge specialist species. I used the second derivatives of the logistic and unimodal models to statistically determine the width of species response zones to edge effects. Beetle species responses to forest edges occurred over far greater scales than previously suspected, with edge response zones for some species extending for more than 1 km. Average edge response zones were 194 m wide and, for many species, began in the forest but extended into the adjacent matrix. Species were categorised according to their responses to fragment area and distance to edge. Closely related species were expected to be placed in similar response categories because they are predicted to share suites of traits that determine their susceptibility or resilience to fragmentation by virtue of common ancestry. Despite many species exhibiting responses that could be grouped into categories, individual species responses to fragmentation were largely idiosyncratic with even closely related species exhibiting strongly contrasting responses to fragmentation.

Intensive agricultural developments and increasing human population has caused severe lowland-forest loss and fragmentation in the western coastal plain in Taiwan over the past centuries. The goal of this study is to explore the multiscale impacts of forest fragmentation on species richness and community composition of lowland-forest birds in Taiwan. At a regional scale, Island Biogeography Theory was applied to examine area and isolation effects on species richness of lowland-forest birds using bird data derived from Breeding Bird Survey Taiwan in 2009 and 2010. I also investigate the differential responses of two functional groups (forest specialists and generalists) to area and isolation effects Furthermore, I examine the relative influences of environmental variables at regional, landscape and local scales on avian community indices and composition in northern Taiwan with a hierarchical multiscale approach. Finally, species vulnerable to forest fragmentation and the ecological traits associated with specie vulnerability to forest fragmentation were identified. Only forest specialist species responded to the regional-scale area and isolation effects. The species richness of forest specialists increased with the size of forest islands, and the community similarity of forest specialist species declined with increasing the distance from the sources of immigrants. Structurally isolated forests may not function as real habitat patches from the view of forest generalists because of their flexibility in utilizing the non-forest matrix. After accounting for the influences of environmental variables at other spatial scales, the regional-scale isolation effect still played a key role in determining avian community composition based on the  presence/absence data set. But local-scale forest condition also explained a considerable amount of variability in the presence/absence data set. The regional-scale isolation effect, however, didn't show significant influences on community composition based on the abundance data set. In contrast, the landscape-scale variables explained the largest amount of variability in the abundance data set at the entire community level. There were six bird species (Parus varius, Dicrurus aeneus, Treron sieboldii, Pericrocotu solaris, Erporniszan tholeuca and Alcippe brunnea) whose occurrence and abundance were both vulnerable to forest fragmentation. Habitat specialization was the ecological traits most strongly associated with their vulnerability / Ph. D.

No description available.

Forest fragmentation is a ubiquitous consequence of anthropogenic land-use change, yet its effects on ecosystem processes and biogenic carbon (C) cycling remain unclear, especially belowground. Forest edges, or the boundary of forest and non-forest land cover, experience altered environmental conditions that affect soil biogeochemical cycling and microbial communities. Urbanization can further alter forest soil dynamics and may interact with perturbations at the forest edge in complex, nonlinear ways. Though soils comprise over 40 % of the global forest C sink, the net effects of interacting global change drivers (e.g., rising temperatures, fragmentation, urbanization) are largely unknown, introducing large uncertainties into estimates of soil C fluxes and our understanding of soil ecology. I co-designed and implemented an observational field campaign of forest edges along an urbanization gradient in Massachusetts to characterize soil C cycling and its drivers from the forest edge to the interior. I use field measurements of soil temperature, moisture and C efflux as CO2, or soil respiration, to find diverging trends in soil C losses at urban and rural forest edges. I find that urban soil respiration rates are less sensitive to rising temperatures than rural soils and that urban edges are even less sensitive than their interior counterparts. I then perform a holistic characterization of soil properties and microbial activity to explore the effects of multiple, simultaneous environmental perturbations on forest edge soils. I report that soil C content does not reflect diverging trends in soil C efflux between rural and urban sites and, instead, is generally lower at the forest edge, suggesting a decoupling between edge soil C pools and fluxes. I also report that soil properties often mediated by human activity, such as pH, temperature, and trace element concentrations, broadly predict soil C dynamics from edge to interior across the urbanization gradient. Finally, I conduct a meta-analysis of published studies on forest edge soil C cycling and its drivers and interpret the findings through a lens of broader global change. I demonstrate that soil conditions converge at the forest edge across the globe, where soils are hotter, drier, and less acidic than the forest interior. I find limited investigation of soil C fluxes and substantial variability in edge soil C stocks, and I conclude that forest edges are not direct analogs for global change experiments. My dissertation demonstrates that soil C cycling is significantly altered by both forest fragmentation and urbanization. I highlight the need for further study both in situ at the forest edge and through multi-factor manipulation experiments to improve our understanding of an increasingly fragmented and urbanized forest landscape.

Lyme disease is one of the most common vector-borne diseases around the world, and the numbers of reported cases are quickly rising. Ixodes ticks are the principal vectors, while Borrelia burgdorferi sensu lato genospecies are the etiological agents of the disease. Climate change, namely global warming, and habitat modification, namely forest fragmentation, are hypothesized to play an active role in this rise in reported cases. An analysis of the primary literature, specifically of studies focused on North America and Europe, was conducted in order to investigate these hypotheses. These studies show that global warming has precipitated a growth in tick populations as well as a northward tick migration, thereby increasing the risk of Lyme disease in emergent and endemic areas alike, for Borrelia spirochetes quickly infect naïve tick populations. Furthermore, published studies support the idea that forest fragmentation near human population centers has also increased the risk of Lyme disease in North America, for edge habitats provide suitable conditions for ticks and provide edible vegetation for the animals on which ticks feed, animals which also serve as hosts for B. burgdorferi sensu lato. In contrast, a decrease in fragmentation was found to facilitate tick invasion and establishment in Europe. These studies demonstrate that anthropogenic habitat modifications of varying types can affect ticks and their host populations and increase the risk of Lyme disease near human population centers. However, more research needs to be done to truly understand the different factors that are precipitating the rising number of cases of Lyme disease since there are significant interactions between climate change, habitat modification, and other drivers not examined here. Furthermore, understanding how these drivers function in specific geographic locations can help scientists and public officials tailor local public health measures appropriately. Finally, researchers and pharmaceutical companies must develop a safe, long-lasting, and effective vaccine against the Lyme disease spirochete, for there is not one currently available. Although easily treatable if diagnosed early, Lyme disease can progress to debilitating disease. Unfortunately, the risk of contracting this illness is currently rising and will continue to rise unless effective preventative measures are employed.

Orientador: Flavio Antonio Maes dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T19:28:28Z (GMT). No. of bitstreams: 1 Aguirre_GuilhermeHenriquede_M.pdf: 4726556 bytes, checksum: 9a2027cf53b2d2b984aec9877670e04e (MD5) Previous issue date: 2008 / Resumo: A Mata Atlântica apresenta altíssima biodiversidade, com destaque para elevada diversidade florística e para o elevado endemismo observado em alguns grupos vegetais. A Mata Atlântica está entre as florestas tropicais mais ameaçadas do mundo e a maioria de seus remanescentes é representada por fragmentos pequenos e alterados, ou áreas maiores encontradas em encostas de montanha com declive acentuado. O conhecimento dos remanescentes florestais quanto à composição florística, distribuição espacial dos organismos e regeneração natural é de grande importância para medidas que visem a conservação da diversidade. Dessa forma, o presente estudo teve como objetivo responder as seguintes questões: como a composição e a diversidade de espécies arbustivo-arbóreas se distribuem em diferentes escalas espaciais, numa região intensamente fragmentada de Mata Atlântica? Características do solo e a proximidade geográfica entre as áreas influenciam na distribuição das espécies no espaço? A composição e diversidade de espécies são relacionadas ao tamanho, forma ou isolamento dos fragmentos? Qual é o potencial de regeneração natural nos fragmentos? Foram estudados 8 fragmentos de Floresta Ombrófila Densa Montana, de 11 a 74 ha, na zona rural do município do São Luiz do Paraitinga, SP. Em cada fragmento foram realizados 30 pontos quadrante, onde foram amostrados indivíduos arbustivo-arbóreos em duas classes: classe I ¿ indivíduos maiores que 1,5 m de altura e com DAP < 5 cm, e classe II ¿ indivíduos com DAP = 5 cm. Ao todo foram amostrados 1920 indivíduos pertencentes a 196 espécies e 44 famílias. De forma geral, as comunidades arbustivo-arbóreas nos fragmentos de mata estudados são muito heterogêneas, sendo a composição de espécies influenciada pela distância geográfica e pelo tamanho dos fragmentos. A riqueza e diversidade nos fragmentos não responderam às métricas usualmente utilizadas em estudos de fragmentação (área, forma e isolamento). O fato de cada fragmento ter apresentado uma composição de espécies diferente, ou seja, uma baixa similaridade de espécies entre fragmentos e a alta diversidade beta, ressaltam a importância da conservação, mesmo de pequenos fragmentos, para a manutenção da elevada diversidade regional. O alto potencial de regeneração natural dos fragmentos analisados em conjunto evidencia ainda mais a importância da manutenção de diferentes fontes de regeneração na manutenção da elevada diversidade florística nos fragmentos florestais da região / Abstract: The Atlantic Forest possesses enormous biodiversity and is highlighted by the high floristic diversity and endemism in some plant groups. The Atlantic Forest is among the most endangered tropical forests in the world and most of its remnants are small and altered fragments, or larger areas in mountains, with pronounced slope. Knowledge of the forest remnants as to floristic composition, spatial distribution of the organisms and natural regeneration is very important for measures that aim diversity conservation. In this manner, the goal of the present study was to answer the following questions: how are composition and diversity of the shrub and tree species distributed across different spatial scales, in a highly fragmented region of Atlantic Forest? Are the composition and diversity of species related to size, shape or isolation of the fragments? What is the natural regeneration potential in the fragments? Eight fragments of Montane Ombrophilous Dense Forest, sized 11 to 74 ha, were studied in the rural area of the Municipality of São Luis do Paraitinga, State of São Paulo, Southeast Brazil. In each fragment 30 point-centered quadrat were established, where shrub and tree individuals were sampled in two groups: group I ¿ individuals larger than 1.5 m height and DBH < 5 cm; group II ¿ individuals with DBH = 5 cm. A total of 1920 individuals from 196 species and 44 families were sampled. In most cases the shrub and tree communities in the studied fragments are very heterogeneous, and the species¿ composition is influenced by geographical distance and fragment size. Richness and diversity in the fragments did not answer to the metrics usually employed in fragmentation studies (area, shape and isolation). The fact that each fragment presented a different species composition, that is, a low species similarity among fragments and high diversity between them, highlight the importance of conservation, even of small fragments, for the maintenance of the high regional diversity. The great natural regeneration potential of the analyzed group of fragments brings out even more the importance of keeping different sources of regeneration in the maintenance of the high floristic diversity in the forest fragments in the region / Mestrado / Ecologia / Mestre em Ecologia