The base rocks of the HRA are mainly schists from the Palaeozoic. The soils are skeletal, with a low amount of oganic matter. The climate is markedly Mediterranean, with a mean annual precipitation of 500 mm, and a mean annual temperature 15.5ºC.
The typical landscape at Grândola mountain is included in the climax area of the Quercoin fagineosuberis alliance, and is dominated by oaks of persistent leaves, namely Quercus suber ( cork-oak) and Quercus ilex ssp. rotundifolia (Holm oak), sometimes accompanied by Quercus faginea (Lusitanian oak). This last species reveals some Atlantic influence. Some cork-oak woodlands ("montado de sobro") located in steep slopes have been progressively abandoned during the last 35 years, which lead to the development of dense shrubs. They belong to the Cisto-Lavanduletae aliance and are dominated by Cistus ssp.
The Field Station is mainly covered by cork-oak woodland ("montado") and is crossed by several temporary small streams. The "montado" is a typical Mediterranean woodland formation resulting from the traditional human use of the landscape and constituting one of the best exemples of the relative harmony between long-standing human activities and the conservation of biodiversity. This ecosystem is considered a habitat of EU interest not only from the botanical point of view, but also because it supports a fauna of high conservation importance. In fact, the first biological characterization of the Field Station [M. Santos-Reis & A.I. Correia, 1999: Caracterização da Flora e Fauna do Montado da Herdade da Riveira Abaixo, Centro de Biologia Amiental, Lisboa, 262pp.], showed that their floristic species of plants, 139 species of insects and 130 species of vertebrates, several of them of conservation concern.
| Nr of Species | Iberian Peninsula Endemics | Portuguese endemics | Relict Species | |
|---|---|---|---|---|
| Fungi | 264 | - | - | 2 |
| Briophytes | 70 | 1 | - | - |
| Vacular Plants | 304 | 12 | - | - |
| Insects | 155 | 1 | 1 | - |
| Fishes | 6 | 4 | 1 | - |
| Amphibians | 12 | 9 | - | - |
| Reptiles | 12 | 7 | - | - |
| Birds | 74 | - | - | - |
| Mammals | 32 | 1 | - | - |
| Freshwater Fishes | Amphibians | Reptiles | Birds | Mammals | |
|---|---|---|---|---|---|
| Data deficient | - | 1 or 2 | - | 1 | 4 |
| Near threatened | - | 1 | 1 | 6 | - |
| Vulnerable | 1 | - | 1 | 2 | 5 |
| Endangered | 2 | - | - | - | 1 |
| Critically endangered | 1 | - | - | - | 1 |
From:
Cabral, M. J. (coord), Almeida, J., Almeida P.R., Dellinger, T., Ferrand de Almeida, N., Oliveira, M. E., Palmeirim, J.M., Queiroz, A.I., Rogado, L., Santos-Reis, M. (eds.) (2005): Livro Vermelho dos Vertebrados de POrtugal. Instituto da Conservação da Natureza. Lisboa.
