QGIS y GRASS para la modelación de corredores ecológicos de lobos en el norte de Portugal

El lobo ibérico es una sub-especie del lobo gris que existe en el norte de Portugal y España, en pequeños grupos aislados al sur del río Douro. En el transcurso del último siglo, sufrió una gran involución, por caso una especie «vulnerable» en España y «en peligro» en Portugal. Actualmente, solo existen 300 lobos en Portugal, en virtud a su alta persecución y destrucción y fragmentación de su hábitat.

Study area in Portugal

Área de estudio en Portugal

Ribeira de Pena is a municipality in the Vila Real district in the north of Portugal. It is a rural municipality, characterized by agriculture, grazing livestock, forest, mountains, valleys and diverse fauna, along with low human density, that provides shelter and food for wolves. Located in a zone of transition between the harsh and mountainous Trás-os-Montes and the verdant Minho, Ribeira de Pena is one of the municipalities that can work like an ecological corridor between areas with higher wolf concentration in the north with lower concentration in the south.

Comencé usando software SIG durante mi curso de biología, y más a menudo durante mi tesis de maestría. En aquel tiempo usaba principalmente software propietario. Después de terminar mi grado de maestría, perdí acceso al software propietario.

Meanwhile, I entered in the new world of Linux. After that I was contacted to help some researchers to model ecological corridors for wolves in Ribeira de Pena, using GIS, since they never worked with this kind of software. Because I was already using Linux instead of windows, my first problem was which software to use. Then I heard about QGIS and decided to give it a try, although it seemed very simplistic and incomplete, when compared to what I already knew. I quickly realized how mistaken I was, and got really enthusiastic with the analytical capabilities QGIS provided, specially with GRASS integration.

To model the ecological corridors, we used the QGIS along with the GRASS plugin. We used several geographic information along with presence data of the species to model the ecological corridors. Here are some of the functions of both QGIS and GRASS used in this case, just to name a few:

  • complemento Interpolación en QGIS: para crear un Modelo Digital de Elevación
  • r.watershed en GRASS: para crear cursos de agua a partir de MDT
  • r.grow.distance en GRASS: genera una capa mapa ráster de distancia a las entidades en la capa de entrada
  • r.reclass en GRASS: Para reclasificar capas
  • r.slope.aspect.slope en GRASS: para calcular la pendiente a partir de un MDT
  • r.mapcalculator en GRASS: para calcular alguna álgebra de mapa simple
  • r.cost.coord in GRASS: creates a raster map showing the cumulative cost of moving between different geographic locations on an input raster map whose cell category values represent cost
  • r.drain en GRASS: Traza un flujo a través de un modelo de elevación en un mapa ráster — aquel usado para crear los corredores

With this work we obtained a map with the potential ecological corridors for wolf in Ribeira de Pena municipality. These are areas to be considered by the city council technicians when planning conservation measures for the species. These corridors are of extreme importance because they can connect the fragile wolf packs in Vila Real in the south with those in the north, which are continuous with those from Peneda-Gerês and Spain far more stable. It is from particular importance those corridors that cross human settlements, like small villages, cities and roads. These areas must be considered critical for wolf conservation, and applied measures to reduce human impact in this species.

Ecological corridors and critical conservation areas for wolves

Corredores ecológicos y áreas críticas de conservación para lobos en el norte de Portugal.

Conclusión

Both QGIS and plugin GRASS are very intuitive with user-friendly interface, with all essential functions to perform most analysis. For what I could see, QGIS and GRASS perform equally as well as the proprietary programs I was most familiar with from college days, with the big advantage of free open-source software, usable in every computer or notebook without licenses, constant upgrades and the ultimate advantage to contribute to it’s improvement and/or tip the developers about some essential function.

El cambio a Linux y luego a QGIS y GRASS fue una de mis mejores decisiones, y aunque puedan haber algunos problemas faltantes, fácilmente solucionables en el futuro con los desarrolladores, no me arrepiento de mi decisión y recomiendo a todos de usarlo.

Autor

Study area in Portugal

Monica Almeida

Este artículo fue contribuido en Julio 2012 por Monica Almeida. Ella es bióloga de la conservación y trabaja en una organización no gubernamental para la preservación del lobo en Portugal.