17 research outputs found

    Remote sensing in support of conservation and management of heathland vegetation

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    Habitat, abundance and productivity of the Asian Houbara Chlamydotis macqueenii in Uzbekistan

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    For a species threatened with exploitation, before embarking on ex situ measures such as population reinforcement through captive breeding, it is important to explore potential in situ measures that could be used to mitigate species off-take by supporting breeding productivity of wild populations. Asian houbara Chlamydotis macqueenii is a globally threatened bird, with continuing declines across Central Asia, mainly due to unregulated hunting and trapping during migration and in winter. This research aims to improve understanding of the breeding season biology of the Asian houbara migratory populations in Central Asia to inform in-situ conservation of the species. Spring fieldwork during 2012–2015 involved distance sampling, nest monitoring and habitat sampling across 14,500 km2 of the Kyzylkum Desert in Uzbekistan. Contrary to expectations, there appeared to be no negative landscape-scale association between livestock density and the abundance of male houbara, and no grazing effect on desert shrub vegetation. Habitat characteristics selected by males at the landscape scale were more likely to maximise visibility of their displays, with higher male abundance in lower shrub vegetation, on gravelly substrate and flatter terrain. The first robust estimate of local male density stratified by different habitats and an estimate of regional numbers were obtained. Houbara nesting success was unaffected by variation in shrub species composition or livestock density, but nests placed within taller vegetation experienced greater success. Satellite-tracking revealed high site-fidelity of males to their display sites and intra-seasonal fidelity of females to breeding areas. During post-breeding dispersal adult birds were found to be using completely different, more productive in terms of vegetation, areas outside their breeding season range. In conclusion I discuss potential implications of key findings for the conservation and management of the Asian houbara population in the Kyzylkum, and their potential relevance to other houbara populations and study systems, and suggest priorities for further research

    The influence of historical and contemporary landscape structure on plant biodiversity: effects on species and genetics

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    Biodiversity describes diversity at different levels of biological organisation, including: habitat diversity; species diversity; and genetic diversity. Understanding the processes that contribute to maintaining biodiversity is a primary concern for both ecology and evolutionary biology. To this end, research into the factors influencing the different levels of biodiversity independently are widespread. However, little is understood about the relationship between the different levels. This study investigates the patterns of habitat, species, and genetic diversity in fragmented internationally important calcareous grasslands, and analyses the spatial and temporal factors influencing them. Finally, the relationship between these levels of biodiversity is examined. Within the South Downs National Park study area, substantial change to habitat diversity and landscape structure was measured between the 1930s and 2012. The transition of semi-natural habitat to agricultural land was the predominate change. Loss of habitat between the 1930s and 2012 was found to influence both species richness and species evenness of vegetation in twelve calcareous grassland study sites. By contrast, none of the variables examined explained the variation in species composition between sites. Further analysis, at the genetic level, for two target species showed that the amount of habitat loss was important in explaining the genetic variation in Cirsium acaule, and soil nutrients were important in explaining the variation of Ranunculus bulbosus. In contrast to the predictions of the species genetic diversity correlation theory, no relationship was established between species and genetic diversity. Similarly, no relationships were found between habitat diversity and diversity at the species or genetic level. Although there were similarities in the factors influencing different levels of biodiversity, habitat diversity, species diversity, and genetic diversity appear to be responding independently to the processes acting on them. As such efforts to conserve biodiversity should consider the influence of conservation strategies on biodiversity holistically, and not focus on a single measure

    Quantification of the risk of Phytophthora dieback in The Greater Blue Mountains World Heritage area

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    Biological invasions exert great pressure on natural ecosystems and conservation areas, the latter of which have been established to conserve biodiversity. The presence of invasive species in natural ecosystems disrupts evolutionary processes, alters species abundance and can potentially lead to extinction (Mack et al., 2000; Crowl et al., 2008). When an invasive species is the cause of plant disease, the potential for that pathogen to survive in a new environment and the expectation of the impacts it may cause, can be estimated from locations where it already occurs. Understanding the dynamics of disease is important for management and research alike, and will hopefully make way for a proactive rather than reactive response. Disease in natural Australian ecosystems caused by the invasive species Phytophthora cinnamomi has been recognised for nearly 100 years (Newhook and Podger, 1972); its devastating impacts have lead to the disease syndrome, Phytophthora dieback, being classified as a Key Threatening Process by the Australian Federal Government (Commonwealth of Australia, 2005). Yet, the assessment of potential disease establishment, that is, disease risk, is limited. This remains true for the globally significant Greater Blue Mountains World Heritage Area (GBMWHA) in New South Wales, a centre of plant and animal conservation. Not only is the understanding of the pathogen distribution limited, so too is knowledge of the potential impacts on flora and the influence climate change may have on disease expression. Management of Phytophthora dieback in the GBMWHA is made increasingly complex by the rugged and remote nature of much of the World Heritage Area, as well as competing demands from tourism, recreation and the impacts of fire and other introduced species. This study aims to address some of these complexities by establishing the suitability of the GBMWHA to P. cinnamomi, its current distribution and the potential for disease. Additionally, with the difficulty of accessing much of the GBMWHA and the risk of disease transmission in mind, an alternate approach to disease identification is trialed. The first task of this project, was concerned with understanding the potential distribution of P. cinnamomi within the GBMWHA using mechanistic modelling and information on the pathogen’s ecology. Most of the GBMHWA was found to be suitable, leading to the acceptance of the first hypothesis that the climatic and topographic conditions of the GBMWHA are conducive to P. cinnamomi establishment. The most conducive areas were characterised by high soil wetness, high rainfall and moderate temperatures, while the areas least conducive were conversely hotter and drier. Although iv the model appeared to overpredict into areas the pathogen was not found, increasing distribution risk was associated with increasing isolations, possibly indicating that the pathogen is yet to reach its potential niche. The modelled distribution of P. cinnamomi was then used to inform a field investigation to determine the actual distribution in the GBMWHA and assess the impact of the pathogen on vegetation communities and individuals. As an invasive species, the distribution of P. cinnamomi was hypothesised to be primarily found in locations with high anthropogenic activity; however it was isolated extensively from remote areas, leading to the rejection of this hypothesis. Disease was never the less expected, albeit sporadic, as per disease expression in other vegetation communities in New South Wales (Arentz, 1974; Walsh et al., 2006; Howard, 2008). Heathland communities that often have a higher incidence of disease (McDougall and Summerell, 2003), had a high rate of pathogen isolation, as well as clear indications of disease in the GBMWHA. Additionally, freshwater wetlands, many of which are endangered ecological communities under Commonwealth and State legislation, had a high rate of pathogen isolation also. The results collected during the field work were then utilised to assess the risk of Phytophthora dieback occurring in the GBMWHA within the context of the disease triangle. The distribution of P. cinnamomi was combined with models of over 130 individual host species to produce a spatially explicit model, quantifying the risk of disease. That a large portion of the GBMWHA is at risk of Phytophthora dieback was not the case, and as such this hypothesis was rejected. Although much of the World Heritage Area had a least some level of risk, greatest risk was associated with a few small areas that occurred at higher elevations with suitable rainfall and temperature conditions. Unfortunately, many of these locations were associated with high levels of tourism and recreation, highlighting the potential for anthropogenic dispersal of P. cinnamomi into, around and out of the GBMWHA. Disease itself has a temporal element which cannot be quantified in one set of field results and as disease spreads the results become outdated quickly (O'Gara et al., 2005). Field-based assessments of disease are expensive and time consuming, and in area as vast and rugged as the GBMWHA, difficult and potentially dangerous. Real-time information on the impacts of disease are therefore needed by land managers to efficiently deploy management strategies (O'Gara et al., 2005). Remote sensing offers an alternative means of assessment not requiring site entry. Vegetation condition can be assessed remotely in all manner of plant systems including the detection and quantification of disease. As such, it was hypothesised here that infection caused by P. cinnamomi could be detected fro

    Monitoring biodiversity in cultural landscapes: development of remote sensing- and GIS-based methods

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    In this thesis, I explore the relationships between structural and compositional landscape properties, and species diversity, using remotely sensed data on a variety of spatial scales. The thesis shows that increased landscape heterogeneity, measured using environmental and spectral variables that were used both separately and combined, is generally positively related to plant species richness. I further found that plant species richness could be predicted with <20% deviance in species numbers, in approximately 80% of the study area within the province of Scania, using a combination of environmental and spectral descriptors of landscape heterogeneity. Further, I used Landsat satellite data, aided by ancillary data on topography and a spectral proxy of seasonal variation in vegetation phenology, to classify historical (ca 1975) and contemporary (ca 2001) land-cover data within the province of Scania, with +85% accuracy. The produced land use/land cover (LULC) data showed correlations with levels of plant species richness, with the proportion of cropland generally being negatively correlated to levels of plant species richness, and the proportion of LULC classes such as grazed grassland, wetland and deciduous forest being positively correlated to levels of plant species richness. Further, the positive change between the historical and contemporary landscapes in the proportion of deciduous forest, and in the number of unique LULC patches, were positively correlated with contemporary levels of plant species richness. I modeled the importance of non-crop habitat types for plant species richness within the province of Scania, and showed that for the promotion of plant species richness, the most wide-spread non-crop LULC types were most important within the most simplified landscapes, while the amount of non-crop small biotopes were most important in more complex landscapes.In a series of studies on grazed grasslands on the Baltic island of Öland, I showed that dissimilarity in Worldview-2 satellite spectral reflectance was related to plant species dissimilarity within a set of grassland plots, and then used spectral dissimilarity to predict levels of plant species richness in other grassland plots. I used HySpex hyperspectral aerial reflectance data to predict plant species diversity (species richness and Simpson’s diversity), using the full range of wavebands and also using a reduced set of wavebands. Finally, I classified grassland plots into age classes using reflectance data from the HySpex hyperspectral sensor, and achieved better classification results when using a reduced set of wavebands compared to using the full range of wavebands.In summary, the findings of this thesis demonstrate that remote sensing and GIS-based methods can be useful tools in the monitoring of cultural landscapes, because of their combined ability to model landscape properties and relate those measures to species diversity, at a range of spatial scales and within a range of habitats

    Remote sensing methods for biodiversity monitoring with emphasis on vegetation height estimation and habitat classification

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    Biodiversity is a principal factor for ecosystem stability and functioning, and the need for its protection has been identified as imperative globally. Remote sensing can contribute to timely and accurate monitoring of various elements related to biodiversity, but knowledge gap with user communities hinders its widespread operational use. This study advances biodiversity monitoring through earth observation data by initially identifying, reviewing, and proposing state-of-the-art remote sensing methods which can be used for the extraction of a number of widely adopted indicators of global biodiversity assessment. Then, a cost and resource effective approach is proposed for vegetation height estimation, using satellite imagery from very high resolution passive sensors. A number of texture features are extracted, based on local variance, entropy, and local binary patterns, and processed through several data processing, dimensionality reduction, and classification techniques. The approach manages to discriminate six vegetation height categories, useful for ecological studies, with accuracies over 90%. Thus, it offers an effective approach for landscape analysis, and habitat and land use monitoring, extending previous approaches as far as the range of height and vegetation species, synergies of multi-date imagery, data processing, and resource economy are regarded. Finally, two approaches are introduced to advance the state of the art in habitat classification using remote sensing data and pre-existing land cover information. The first proposes a methodology to express land cover information as numerical features and a supervised classification framework, automating the previous labour- and time-consuming rule-based approach used as reference. The second advances the state of the art incorporating Dempster–Shafer evidential theory and fuzzy sets, and proves successful in handling uncertainties from missing data or vague rules and offering wide user defined parameterization potential. Both approaches outperform the reference study in classification accuracy, proving promising for biodiversity monitoring, ecosystem preservation, and sustainability management tasks.Open Acces

    Europe's ecological backbone: recognising the true value of our mountains

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    Europe's mountain areas have social, economic and environmental capital of significance for the entire continent. This importance has been recognised since the late 19th century through national legislation; since the 1970s through regional structures for cooperation; and since the 1990s through regional legal instruments for the Alps and Carpathians. The European Union (EU) first recognised the specific characteristics of mountain areas in 1975 through the designation of Less Favoured Areas (LFAs). During the last decade, EU cohesion policy and the Treaty of Lisbon have both focused specifically on mountain

    Wildlife Protection and Habitat Management

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    The management of wildlife populations and their habitats are interdisciplinary fields that encompass many scientific disciplines that also impact the lives of people. Therefore, these are truly applied sciences where human dimensions play an important role.This book highlights the importance of conducting rigorous studies to design and implement the effective management and restoration of wild populations and their habitats. A new paradigm in conservation is developing that goes beyond the boundaries of protected areas to achieve the goal of sustainable development. The 16 papers in this book, including reviews and a project report, cover a broad range of topics, exploring a diversity of subjects that are representative of current practices and novel applications.We would like to thank both the MDPI publishers and editorial staff for their support and help during the process of editing this book, in addition to the authors for their contributions
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