Collserola Park is a jewel that many cities would like. A few kilometers from more than three million people, eight thousand five hundred hectares of forests and other natural or semi-natural systems enjoy protection under the figure of the park’s special plan. The continuity and improvement of the ecological, economic and social functions of Collserola must be objectives that can not be waived for the citizens, park managers and politicians of the many administrations involved.
1. Collserola has the vocation of a natural park.
2. A natural park is a very different entity from an urban park. The main difference lies in the fact that, in natural parks, human intervention is much lower, and the role of natural processes much greater than in an urban park.
3. Natural spaces, including natural parks, must be large in order to be able to generate the ecological goods and services that they provide for free.
4. The persistence and ecological integrity of a natural space are facilitated when space is bigger, and they are increasingly engaged when the surface of the park is reduced and when more are the anthropogenic pressures on the outer and inner borders (If they exist) of the space.
5. Given its location in the Barcelona metropolis, Collserola Park has an intensive and diversified public use. This public use is one of the reasons for being in the park and contributes to the quality of life of the citizens who enjoy it. However, excessive frequenting in some areas, and certain particularly aggressive activities with the environment or simply illegal, is a threat to the ecosystems of the park.
6. Despite this vocation for public use, it is important to keep in mind that natural spaces are also useful even if they are not used. It is not necessary or desirable that all the places in the park be accessible to the people. Non-accessible areas play an important role in the persistence of species, communities and ecological processes.
7. Ecological isolation is one of the main threats to the maintenance of ecosystems and the biological richness of Collserola.
8. The ecological isolation of Collserola is growing due to urban expansion and the proliferation of infrastructures. Reducing this isolation must be one of the main objectives of the Strategic Plan.
9. Plants or their genes also move: ecological connectivity is not important only for terrestrial vertebrates but also for plants and invertebrates.
10. To maintain the genetic diversity of semi-isolated populations, like many of those in Collserola, what is important is that organisms coming from outside.
11. Conversely, parks such as Collserola can act as “repoblators” due to the emigration of individuals born within the park to other territories.
12. The reduction of the ecological isolation of Collserola necessarily requires looking beyond the limits of the park. It is necessary especially to implement (and where necessary, restore) a system of ecological connections that guarantees the maintenance or recovery of ecological flows (of organisms, of genes, of matter and of energy) between Collserola and: (1) the pre-coastal mountain range ; And (2) the other massifs of the coastal mountain range.
13. The most pressing problem for the maintenance of the ecological connections of Collserola is in the contact between the park and the valley plain. There are still important agricultural and agroforestry areas in the valleys that have a key role as a food area, as a habitat, as an ecological connector and as buffer zones.
14. The Collserola Strategic Plan must set as its highest priority objective to conserve (wherever possible and desirable, recover) the agricultural and agroforestry areas of the Vallès plain that are in contact with the park or in its vicinity .
15. The greatest current threat to the maintenance of the ecological connectivity of Collserola is the development of the Direccion Center, in the municipality of Cerdanyola del Vallès. The massive urban development projected in this area will pay 340 hectares of dry land crops that constitute the last large rural window that is left in Collserola and will culminate the ecological isolation of the park with respect to the valley plain and the pre-coastal mountain range.
Catedràtic d’Ecologia de la Universitat Autònoma de Barcelona Investigador del CREAF (Centre de Recerca Ecològica i Aplicacions Forestals)