516 research outputs found
A Genetic Algorithm solver for pest management control in Island systems
Island conservation management is a truly multidisciplinary problem that requires considerable knowledge of the characteristics of the ecosystem, species and their interactions. Nevertheless, this can be translated into an optimisation problem. Essentially, within a limited budget, a manager needs to select the conservation actions according to expected payoffs (in terms of protecting or restoring desired species) versus cost (the amount of resources/money) required for the actions. This paper presents the problem in terms of a knapsack formulation and develops optimisation techniques to solve it. From this, decision-support software is being developed, tailored to meet the needs of pest control on islands for conservation managers. The solver uses a Genetic Algorithm and incorporates a simplified model of the problem. The solver derives strategies that reduce the number of threats, allowing the preservation of desired species. However, the problem model needs further refinement to derive truly realistic options for conservation managers
Optimality In Reserve Selection Algorithms: When Does It Matter And How Much?
This paper responds to recent criticisms in Biological Conservation of heuristic reserve selection algorithms. These criticisms primarily concern the fact that heuristic algorithms cannot guarantee an optimal solution to the problem of representing a group of targeted natural features in a subset of the sites in a region. We discuss optimality in the context of a range of needs for conservation planning. We point out that classical integer linear programming methods that guarantee an optimal solution, like branch and bound algorithms, are currently intractable for many realistic problems. We also show that heuristics have practical advantages over classical methods and that suboptimality is not necessarily a disadvantage for many real-world applications. Further work on alternative reserve selection algorithms is certainly needed, but the necessary criteria for assessing their utility must be broader than mathematical optimality
Effectiveness Of Alternative Heuristic Algorithms For Identifying Indicative Minimum Requirements For Conservation Reserves
We compared the results of 30 heuristic reserve selection algorithms on the same large data set. Twelve of the algorithms were for presence-absence representation goals, designed to find a set of sites to represent all the land types in the study region at least once. Eighteen algorithms were intended to represent a minimum percentage of the total area of each land type. We varied the rules of the algorithms systematically to find the influence of individual rules or sequences of rules on efficiency of representation. Rankings of the algorithms according to relative numbers or areas of selected sites needed to achieve a specified representation target varied between the full data set and a subset and so appear to be data-dependent. We also ran optimizing algorithms to indicate the degree of suboptimality of the heuristics. For the presence-absence problems, the optimizing algorithms had the advantage of guaranteeing an optimal solution but had much longer running times than the heuristics. They showed that the solutions from good heuristics were 5-10% larger than optimal. The optimizing algorithms failed to solve the proportional area problems, although heuristics solved them quickly. Both heuristics and optimizing algorithms have important roles to play in conservation planning. The choice of method will depend on the size of data sets, the representation goal, the required time for analysis, and the importance of a guaranteed optimal solution
The performance of existing networks of conservation areas in representing biodiversity
It is widely held that existing reserve systems are inadequate in representing the diversity of biological features of the regions in which they reside. Evidence for this argument has, however, derived principally from analyses of the efficiency of networks when compared with a minimum set that represents each species at least once. Here, we examine the efficiency of the system of Sites of Special Scientific Interest (SSSIs) in representing wetland plants in fen sites in the Scottish Borders, a region where reserve networks might be expected a priori to perform reasonably well in this regard. The results support the general contention that networks have been designated in an inefficient manner.
However, examined in terms of effectiveness (measured as the gap between the representation target required and the one attained by the existing network), the SSSI system is actually a rather good way of representing diversity. This result is consistent when each of several very different representation targets is evaluated, and suggests that a more balanced approach to evaluating the performance of reserve networks should be employed, and that general statements based on existing analyses should be treated cautiously
Using temporally explicit habitat suitability models to assess threats to mobile species and evaluate the effectiveness of marine protected areas
A principal role of marine protected areas (MPAs) is to mitigate the decline of biodiversity. A key part of this role is to reduce the effects of fisheries on bycatch of vulnerable species. Bycatch can have an impact on species by reducing population sizes, and an ecosystem-level impact through the significant removal of biomass and subsequent trophic changes. In this regard, it is crucial to refine methods for quantifying interactions between fisheries and bycatch species, and to manage these interactions spatially. A new method is presented for quantifying interactions between fisheries and bycatch species at high spatial and temporal resolutions. Temporally explicit species distribution models are used to examine temporal dynamics of fisheries and bycatch. This method is applied to Australia's Eastern Tuna and Billfish Fishery to estimate interactions with seven principal bycatch species. The ability of MPAs to reduce bycatch is evaluated, and considerations are outlined for the spatial management of fishery-bycatch species interactions. Australia's Commonwealth Marine Reserve Network had a minimal impact on bycatch reduction under both the 2012 proclaimed and the 2015 panel-recommended zonings. These results highlight the need for threats to marine biodiversity to be incorporated directly into design of MPAs, and for close scrutiny of assumptions that threats will be incidentally abated after MPAs have been proclaimed, or that off-reserve mechanisms will compensate for inadequacies of MPAs
The Reliability of Test Discriminations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66658/2/10.1177_001316445501500404.pd
O YouTube: potencialidades pedagógicas na aprendizagem da LÃngua Inglesa no 1.º ciclo do ensino básico
Mestrado em Ensino Precoce do InglêsO presente projeto de investigação procurou apresentar o YouTube como um
banco de recursos audiovisuais, promotor do desenvolvimento das macrocapacidades de
audição e de expressão oral, no processo de ensino/aprendizagem da LÃngua Inglesa no
1.º ciclo do ensino básico.
Desta forma, procurámos tecer algumas considerações relativamente à origem e
natureza orgânica do YouTube, que nos conduziram à visualização e à exploração de
vÃdeos publicados no website, que promovessem, simultaneamente, o usufruto de
imagem e som e, por conseguinte, o cumprimento de objetivos pedagógicos inerentes Ã
aprendizagem significativa da lÃngua estrangeira.
O trabalho de pesquisa centrou-se num estudo de caso, cujo desenvolvimento
providenciou a aplicação de vÃdeos e a realização de atividades diversas, numa turma de
alunos do 4.º ano de escolaridade, tendo como base princÃpios decorrentes de métodos e
abordagens utilizados no ensino de Inglês a crianças, auscultando-se o seu grau de
envolvimento e participação no processo de aprendizagem.
Do mesmo modo, e porque consideramos fundamental a troca de ideias e a
partilha de experiências e práticas, especialmente no que se refere ao campo de ação da
Educação, procurou-se estabelecer práticas de trabalho colaborativo e colegialidade
entre as professoras envolvidas no decurso da investigação realizada.This research work aimed at describing the YouTube as a source of audiovisual
materials, favourable to the development of listening and speaking skills concerning the
process of English language teaching and learning in primary schools.
Bearing in mind YouTube’s origins and organic nature, we engaged in selecting
and exploring videos uploaded on the website, which conveyed both image and sound,
in order to attain a set of pedagogical objectives aimed at a meaningful learning of the
foreign language.
The research work redefined itself as a case study, whose development consisted
in using a number of videos and activities with fourth graders, having in mind principles
from preferred methods and approaches in the teaching of English to Young Learners,
as well as the assessment of their degree of involvement and participation in the
learning process.
Furthermore, and because we consider the sharing of ideas, experiences and
practices of major importance, especially as far as Education is concerned, we tried to
develop and enhance collaborative and collegial work between the teachers engaged in
the course of the research work
Land systems as surrogates for biodiversity in conservation planning
Environmental surrogates (land classes) for the distribution of biodiversity are increasingly being used for conservation planning. However; data that demonstrate coincident patterns in land classes and biodiversity are limited. We ask the overall question, "Are land systems effective surrogates for the spatial configuration of biodiversity for conservation planning?" and we address three specific questions: (1) Do different land systems represent different biological assemblages.? (2) Do biological assemblages on the same land system remain similar with increasing geographic separation? and (3) Do biological assemblages on the same land system remain similar with increasing land system isolation? Vascular plants, invertebrates, and microbiota were surveyed from 24 sites in four land systems in and northwest New South Wales, Australia. Within each land system, sites were located to give a hierarchy of inter-site distances, and land systems were classified as either "low isolation" (large and continuous) or "high isolation" (small patches interspersed among other land systems). Each type of land system supported components of biodiversity either not found, or found infrequently, on other land systems, suggesting that land systems function as surrogates for biodiversity, and that conservation-area networks representing land-system diversity will also represent biological diversity. However, the majority of taxa were found on more than one land-system type, suggesting that a large proportion of the plant, arthropod, and microbial biodiversity may be characterized by widespread species with low fidelity to particular land systems. Significant relationships between geographic distance among sites and differences among assemblages were revealed for all taxa except the microbiota. Therefore, as sites on the same land system were located farther apart, the assemblages at those sites became more different. This finding strongly suggests that conservation planning based on land-system diversity should also sample the geographic range occupied by each land system. Land-system isolation was not revealed to be a significant Source of variation in assemblage composition. Our research finds support for environmental surrogates for biodiversity in conservation planning, specifically the use of land systems and similarly derived land classifications. However, the need for explicit modeling of geographic distance in conservation planning is clearly indicated
Applying Decision-Theory Framework to Landscape Planning for Biodiversity: Follow-up to Watson et al
Because socioeconomic factors drive conservation planning, we believe that to be relevant to on-the-ground projects, conservation science should be focused more on formulating problems explicitly and showing how the broad variety of decision-making tools can be used to deliver solutions. Conservation biology cannot operate outside the reality of financial limitations
Effectiveness of Biodiversity Surrogates for Conservation Planning: Different Measures of Effectiveness Generate a Kaleidoscope of Variation
Conservation planners represent many aspects of biodiversity by using surrogates with spatial distributions readily observed or quantified, but tests of their effectiveness have produced varied and conflicting results. We identified four factors likely to have a strong influence on the apparent effectiveness of surrogates: (1) the choice of surrogate; (2) differences among study regions, which might be large and unquantified (3) the test method, that is, how effectiveness is quantified, and (4) the test features that the surrogates are intended to represent. Analysis of an unusually rich dataset enabled us, for the first time, to disentangle these factors and to compare their individual and interacting influences. Using two data-rich regions, we estimated effectiveness using five alternative methods: two forms of incidental representation, two forms of species accumulation index and irreplaceability correlation, to assess the performance of ‘forest ecosystems’ and ‘environmental units’ as surrogates for six groups of threatened species—the test features—mammals, birds, reptiles, frogs, plants and all of these combined. Four methods tested the effectiveness of the surrogates by selecting areas for conservation of the surrogates then estimating how effective those areas were at representing test features. One method measured the spatial match between conservation priorities for surrogates and test features. For methods that selected conservation areas, we measured effectiveness using two analytical approaches: (1) when representation targets for the surrogates were achieved (incidental representation), or (2) progressively as areas were selected (species accumulation index). We estimated the spatial correlation of conservation priorities using an index known as summed irreplaceability. In general, the effectiveness of surrogates for our taxa (mostly threatened species) was low, although environmental units tended to be more effective than forest ecosystems. The surrogates were most effective for plants and mammals and least effective for frogs and reptiles. The five testing methods differed in their rankings of effectiveness of the two surrogates in relation to different groups of test features. There were differences between study areas in terms of the effectiveness of surrogates for different test feature groups. Overall, the effectiveness of the surrogates was sensitive to all four factors. This indicates the need for caution in generalizing surrogacy tests
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