Emma Pérez-Chacón Espino

Vegetation, distance to the coast, and aeolian geomorphic processes and landforms in a transgressive arid coastal dune system

The main objective of this study was to determine the nature and relative importance of environmental factors that shape the distribution of dune vegetation in the Maspalomas dune field in the Canary Islands, an arid transgressive dune system. Environmental factors were defined according to their expression related to the linear distance from the coast and to the local aeolian geomorphic process-landform context. Plant communities were characterized through an integration of field mapping, digital orthophoto interpretation and GIS analysis. The vegetation of the study area consists of 19 plant communities. In areas with active sedimentary processes, vegetation tends to be localized in slacks. In areas with more stabilized landforms, vegetation appears at both dunes and slacks. In conclusion, the main factor controlling the distribution of vegetation in the transgressive dune system of Maspalomas is the local aeolian sedimentary process-landform context. Distance to the coast is not as significant as an influence. The gradient structuring of environmental factors associated with retentive coastal dune systems and expressed as distance to the coast does not fully capture the biogeomorphic dynamism of transgressive dune fields.

Proposal for new EU habitats associated with coastal dune fields of the Macaronesian region. A case study in the Canary Islands (Spain)

The aim of this work is to identify habitats of European interest for the existing dunes in the Canaries, in order to provide data for their proper management. Dune systems considered were the following: aeolian sedimentary systems that cover both most of the island of La Graciosa and also the dune fields of Maspalomas (Gran Canaria) and Corralejo (Fuerteventura). The methodology consisted of overlapping layers of habitats and vegetation by using geographic information systems, so the correspondence between habitat and plant community are analyzed. The results indicate that dune habitats in the Canary Islands have not been well defined. The habitat “2110 embryonic shifting dunes” is associated with several situations incompatible with their biotic and abiotic characteristics. Meanwhile, habitat “2130 fixed dunes with herbaceous vegetation (grey dunes)” is linked, among others, to the phytosociological association Traganetum moquinii. However, embryonic dune formation in the Canaries is mainly done by this community, which is inconsistent with its inclusion in the grey dunes habitat. The proposed habitats of European interest associated with dunes in the Canaries are the following: Coastal shifting dunes with Traganum moquinii, dunes with Tamarix canariensis, Macaronesian aeolian sand sheets and humid dune slacks. It is also suggested the need for a comprehensive study of dune habitats existing in the Canaries and Macaronesia, covering the whole of aeolian sedimentary systems, performing a proper identification, characterization and detailed mapping of these habitats, based on both the existing vegetation and also on the associated landforms and geomorphic processes.

Procedure to automate the classification and mapping of the vegetation density in arid aeolian sedimentary systems

The temporal variation in vegetation cover in aeolian sedimentary systems, especially those in arid regions, provides an indication of environmental change. Based on this, the objective of this paper is to design a simple method for classifying the vegetation density of arid aeolian sedimentary systems through the digital processing of aerial images. The green band of a high resolution orthophoto of La Graciosa island (Canary Islands, Spain) is used as an example. The pixels identified as vegetation were vectorized to point geometry, the vegetation density was then calculated, and a digital vegetation density model (DVDM) thereby obtained. Both spatial and statistical analyses were performed to find the optimal procedure to achieve the objective. Speed, objectivity, cost, and the possibility of working with historical records are discussed, and the proposed method is compared with others based on visual analysis or digital remote sensing. The importance of this method for countries with less research funding or low GDP per capita is also discussed. The proposed procedure opens up future lines of research for comparison of results across various environmental and anthropogenic variables. In addition, vegetation density can be used as a variable in computational fluid dynamic modeling of vegetation in arid dune systems.

Aeolian Sedimentary Systems of the Canary Islands

The aeolian sedimentary systems of the Canary Islands have certain natural and socio-economic characteristics that make them differentiated environments, both in the context of the dune fields of Spain and Europe. This is a consequence of their location in intraplate hot spot volcanic islands, their climatic conditions, the high pressure exerted on them by society and the lack of adequate management measures. The relationship between their elements and the continuous change to which they are exposed make them environments with high complexity and fragility. In recent decades, some research lines have been opened around these systems, based on geomorphological, biogeographic, historical, cultural, landscape and socio-ecological analysis. These new approaches have allowed to expand the knowledge about the diversity and complexity of the processes that occur in these systems, as well as to obtain information regarding their management.

Changes in use and soil erosion: diachronic analysis (1960-2012) GIS in Guiniguada basin (Gran Canaria, Canary Islands, Spain)

espanolSe analiza la evolucion de las tasas de erosion tras los cambios de usos del suelo producidos entre 1960 y 2012. Para ello se adapta el modelo empirico USLE a las especificidades de Gran Canaria, y se implementa mediante un SIG. Los resultados muestran que la eficacia antierosiva y la calidad paisajistica, de las superficies abancaladas de la cuenca, se han visto desigualmente afectadas por el incremento de las tasas de erosion. https://doi.org/10.14195/1647-7723_24_5 EnglishThe evolution of the erosion rates in the Guiniguada ravine (Gran Canaria, Spain), between 1960 and 2012, is here analyzed. For the study, the empirical model USLE is applied, adapting it to the specificities of the Gran Canaria, and the analysis are developed using GIS. The results show that the anti-erosion efficiency and landscape quality of terraced surfaces in the study area have been unevenly affected by the increase of erosion rates. https://doi.org/10.14195/1647-7723_24_5

LLUVIAS E INUNDACIONES EN LOS CENTROS TURÍSTICOS DE GRAN CANARIA: EL CASO DE SAN BARTOLOMÉ DE TIRAJANA

The southern region of Gran Canaria has undergone a process of intense transformation as a result of the tourist installations built in the area since 1962. The environmental consequences of this process include fl ooding. This study aims to determine whether the building of tourist installations is related to the increase, over recent decades, in fl oodrelated damage. To this end, a diachronic analysis from 1962 to the present day has been carried out, comparing the evolution observed between bouts of intense rainfall and the problems encountered. The results show that the recent increase in damage from fl ooding is explained by the way in which urban development, together with related tourist infrastructure, has spread.