Postglacial migration supplements climate in determining plant species ranges in Europe

The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to postglacial colonization. Climate was important for all species, while postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role

Community core detection in transportation networks

This work analyses methods for the identification and the stability under perturbation of a territorial community structure with specific reference to transportation networks. We considered networks of commuters for a city and an insular region. In both cases, we have studied the distribution of commuters' trips (i.e., home-to-work trips and viceversa). The identification and stability of the communities' cores are linked to the land-use distribution within the zone system, and therefore their proper definition may be useful to transport planners.Comment: 8 pages, 13 figure

Developing a conceptual model of marine farming in New Zealand

Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today

Agroecological aspects of evaluating agricultural research and development:

In this paper we describe how biophysical data can be used, in conjunction with agroecological concepts and multimarket economic models, to systematically evaluate the effects of agricultural R&D in ways that inform research priority setting and resource allocation decisions. Agroecological zones can be devised to help estimate the varying, site-specific responses to new agricultural technologies and to evaluate the potential for research to spill over from one agroecological zone to another. The application of agroecological zonation procedures in an international agricultural research context is given special attention.Agricultural research., Technological innovations., Agricultural economics and policies.,

Elevational and latitudinal changes in tree associations and diversity in the Eastern Arc mountains of Tanzania

A total of 200 variable-area plots covering 20 3 ha containing 4000 trees with a basal area of 921 4 m2 were assessed over a combined elevational range of 410-2180 m in the moist forests of three Tanzanian Eastern Arc mountains: West Usambara, Nguru and Udzungwa. Plot data were ordinated on the basis of species presence/absence, frequency and basal area Axis 1 of ordinations based on species presence/absence are correlated with elevation Axis 1 of the frequency-weighted ordination was correlated with elevation in the Nguru and Udzungwa mountains, but plots from the West Usambara showed a rainfall-related discontinuity Axis 1 of the West Usambara basal area-weighted ordination showed evidence of long-term dynamics of Ocotea usambarensis and in the Udzungwa mountains was determined by presence of Parinari excelsa Plot diversity was not correlated with elevation or latitude, but was lower in disturbed, low rainfall or more seasonal forest. Stem density was positively correlated with elevation and was greater on ridge tops than valley sides and valley bottom

High speed/high capacity railway and regional development - evaluation of effects on spatial accessibility

In the last decade the theme of high speed infrastructure in Italy has been deeply debated, with different political and technical opinions, which have expanded the time for projects and constructions. As a consequence of this long debate, a redefinition of the whole system, moving from high speed to high speed/high capacity railway system (HS/HC) has been agreed. This new model can be considered more suitable especially for the northern Italy corridor, which is highly populated and densely urbanised. Moreover, while the environmental effects of transportation facilities and of high speed infrastructure are relatively well known in literature since the Environmental Impact Assessment (EIA) procedure has been applied to several study cases, the effects on economical and geographical structure are less studied and so quite often misunderstood or underestimated. According to a demand-side approach, infrastructure investments will follow mobility needs by the economical system, while from a supply-side approach infrastructure are a crucial means of regional growth. This paper presents a study case in northern Italy (the Milan-Verona track, of about 140 km of lenght), and it shows how spatial effect of a transport network can spread off far from the line, determining a new regional hierarchy and new location opportunity in a wide and highly populated area. A comparison has been made between the original high speed model and the most recent high speed-high capacity model. In the two cases the work investigates what is the area where the new infrastructure shows effects, at short and long term. With a spatial interaction model, used to represent residential location in relation to the distribution of workplaces, HS/HC line efficiency by accessibility calculus has been measured, showing several important results. Those results may be of interest even in similar European context where the HS programme is developing.

Residents\u27 Perceptions and Attitudes Towards Native American Gaming (NAG) in Kansas: Proximity and Number of Trips to NAG Activity

This study assessed the perceptions and attitudes toward Native American Gaming (NAG) development in the State of Kansas. By using the resident support for tourism model developed by Perdue, Long, and Allen (1990), this study assessed perceptions and attitudes of residents in relation to their proximity to NAG activity and their number of visits to Native American casinos in the last 12 months. A survey was administered to 1038 households on a population proportionate basis in Brown County (35.65%), Doniphan County (25.30%), and Jackson County (39.05%) in the State of Kansas. Significant differences were found between distance from NAG activity and the perception of overcrowding in the county. Additionally, significant differences were noted between number of visits and the perception of income benefits, employment opportunities, condition of the local economy, quality of life in the county, entertainment opportunities, illegal drug activities, standard of living, meeting interesting people, social opportunities and overall quality of life

Integrated Modeling Approach for the Transportation Disadvantaged

Transportation models have not been adequate in addressing severe long-term urban transportation problems that transportation disadvantaged groups overwhelmingly encounter, and the negative impacts of transportation on the disadvantaged have not been effectively considered in the modeling studies. Therefore this paper aims to develop a transportation modeling approach in order to understand the travel patterns of the transportation disadvantaged, and help in developing policies to solve the problems of the disadvantaged. Effectiveness of this approach is tested in a pilot study in Aydin, Turkey. After determining disadvantaged groups by a series of spatial and statistical analyses, the approach is integrated with a travel demand model. The model is run for both disadvantaged and nondisadvantaged populations to examine the differences between their travel behaviors. The findings of the pilot study reveal that almost two thirds of the population is disadvantaged, and this modeling approach could be particularly useful in disadvantage-sensitive planning studies to deploy relevant land use and transportation policies for disadvantaged groups