Pilar Martín de Agar
Complutense University of Madrid
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Publication
Featured researches published by Pilar Martín de Agar.
Landscape Ecology | 2006
María José Roldán Martín; Carlos L. de Pablo; Pilar Martín de Agar
Changes in the landscape from 1946 to 1999 were studied according to changes in the land uses, boundaries and mosaics therein. The abundances of the different categories of these three landscape elements were calculated using land use maps. Their frequency profiles were compared based on their richness, evenness and diversity. Richness of land uses does not noticeably change. However, these slight changes are spatially perceptible in the landscape when changes in the boundaries and mosaics are considered. For the three landscape elements the least diverse landscapes are obtained in the initial year. The highest landscape diversity is reached, however, in the intermediate years when boundaries or mosaics are considered, whereas the highest value based on land uses occurs in the final period studied. Considering that land uses, boundaries and mosaics provide different information on landscape characteristics and qualities, conditional entropy analyses were conducted in order to ascertain which of the types of landscape elements is most related to landscape change. Boundaries are the element most related to landscape change. Mosaics, however, are the element that best describe each of the years because they integrate the information on land uses and boundaries. From an ecological and management point of view, the three elements should be considered as opposed to just land uses. They compliment each other in the information provided by each one in relation to changes occurring and the effects thereof on landscape structure and functioning.
Forest Ecology and Management | 1998
María F. Schmitz; José A. Atauri; Carlos L. de Pablo; Pilar Martín de Agar; Alejandro J. Rescia; F. D. Pineda
Abstract The substitution of agricultural land uses and native forests in the North of Spain by Pinus radiata plantations was studied. The variability of a set of soil samples taken in these plantations, and other types of land uses, was analyzed. The sites studied have had characteristic changes in land use, being submitted to different degrees of exploitation and types of management practices. Clear-cutting and planting techniques, along with the selective logging from the main mass of trees and the clear felling of the understorey, cause an alteration of the edaphic system which is seen in its lesser ability to mobilize necromass, recycle nutrients and increase the carbon/nitrogen ratio. Old pine plantations, forests of Fagus sylvatica and Quercus spp. and pastures also show a noteworthy variability in their edaphic characteristics depending on the type of management. Forests with very similar appearance may have soils with very different necromass recycling capabilities. The same occurs with pine plantations. The usual procedure involved in land planning, characterizing the degree of nature conservation by means of identification of large units of vegetation or farmland uses is highlighted. In territories with intense human management, as here considered, this degree can best be assessed through the study of the soil characteristics.
Environmental Management | 1995
Pilar Martín de Agar; Carlos L. de Pablo; F. D. Pineda
A procedure to map the ecological structure of a territory is shown. The ecological structure is considered to be the result of the spatial coincidence of numerous physical and biological variables and the spatial connections between territorial sectors. The spatial correspondence patterns of such variables and sectors are detected by multivariate ordination analyses and were mapped using trend surface analysis (TSA). According to these premises an ecological map of the Madrid area was designed. This ecological map is objective: its characteristics do not depend on decisions by the specialists who compile it. The information it contains is based on the systematic analysis of the spatial relationships between numerous variables and territorial sectors. The use of TSA allows a synthesis of the way in which general gradients easily show the ecological spatial variability of the territory (low degree polynomials) or a superimposed—cellular or equipotential—structure appears on those gradients (high degree polynomials). The usefulness of the map is that it shows the ecological structure of the territory and the spatial linkages between the elements of this structure. The accuracy of the map showing these relationships may be ascertained by the fit to trend surfaces of increasing degree. The test was considered to be satisfactory as the results agreed with the prior ecological descriptions of the area. The procedure is thus deemed applicable to lesser known areas and can be very useful in planning studies.
Landscape Research | 2012
Carlos L. de Pablo; María J. Roldán-Martín; Pilar Martín de Agar
Abstract Landscape is organised in mosaics: sets of patches with a defined pattern of boundaries through which patches interact. Changes in patches cause changes in mosaics. Landscape change has two components: a quantitative one, referring to the areas in which changes happen, and a qualitative one, referring to the degree of similarity among the mosaics substituting each other. The quantitative component informs on the magnitude of the change: the total area in which landscape mosaics have changed; the qualitative one informs on the significance thereof: the ecological differences between the mosaics substituting each other. This paper presents an index for quantifying landscape change and for discriminating between magnitude and significance therein. It was tested by study of changes in the landscape mosaics in Madrid, Spain. Results show that the index developed is useful for this purpose. This enables objective comparison of different landscape changes presenting different combinations of magnitude and significance.
Journal of Environmental Management | 2016
Pilar Martín de Agar; Marta Ortega; Carlos L. de Pablo
We develop a procedure for assessing the environmental value of landscape mosaics that simultaneously considers the values of land use patches and the values of the boundaries between them. These boundaries indicate the ecological interactions between the patches. A landscape mosaic is defined as a set of patches and the boundaries between them and corresponds to a spatial pattern of ecological interactions. The procedure is performed in two steps: (i) an environmental assessment of land use patches by means of a function that integrates values based on the goods and services the patches provide, and (ii) an environmental valuation of mosaics using a function that integrates the environmental values of their patches and the types and frequencies of the boundaries between them. This procedure allows us to measure how changes in land uses or in their spatial arrangement cause variations in the environmental value of landscape mosaics and therefore in that of the whole landscape. The procedure was tested in the Sierra Norte of Madrid (central Spain). The results show that the environmental values of the landscape depend not only on the land use patches but also on the values associated with the pattern of the boundaries within the mosaics. The results also highlight the importance of the boundaries between land use patches as determinants of the goods and services provided by the landscape.
Bosque (valdivia) | 2012
Lídia Sanches Bertolo; Pilar Martín de Agar; Carlos L. de Pablo; Rozely Ferreira dos Santos
This study assumed that the spatial identification of mosaics obtained by the analysis of interactions between frontiers over time would be a great strategy to obtain planning units, since the boundaries reveal the changes, heterogeneity and fluxes in a landscape. For this purpose, we selected 16 watersheds in Sao Sebastiao Island (Sao Paulo, BR), mapped the land use and cover (1962 and 2009) and built matrices of patches by boundaries. The analysis of these matrices using multivariate ordination and clustering allowed us to identify mosaics. The mosaics showed very well the temporal diversity of interactions across frontiers and the landscape conservation status, but had limitations to indicate management practices.
Environmental Management | 2004
José A. Atauri; Carlos L. de Pablo; Pilar Martín de Agar; María F. Schmitz; F. D. Pineda
Landscape Ecology | 2013
Elisa Hardt; Rozely Ferreira dos Santos; Carlos L. de Pablo; Pilar Martín de Agar; Erico Fernando Lopes Pereira-Silva
Ecological Indicators | 2015
Lídia Sanches Bertolo; Rozely Ferreira dos Santos; Pilar Martín de Agar; Carlos L. de Pablo
Applied Ecology and Environmental Research | 2018
Elisa Hardt; C.L. Pablo; Pilar Martín de Agar; R. F. Dos Santos; Erico F.L. Pereira-Silva