The hills of Almatret, together with the Natural Area of Riba-roja, form part of the network Natura 2000. Formerly used for mining, some good examples of pine forests can be found, mainly in the shady sides. Furthermore, there are significant forest islets; the uncultivated part is covered by a dense forest of white pine, with an undergrowth of continental maquis featuring kermes oak (Quercus coccifera) and black hawthorn (Rhamnus lycioides), and calcicolous thickets.
It hosts an area of great biogeographic importance as a centre for the conservation of endemic species. In terms of wildlife, in addition to the aquaculture (such as otters or catfish) there is a great diversity of bird species: perching birds, eagles and vultures. And terrestrial animals: wild boars, roe deer, foxes... This area was declared a Site of Community Importance (SCI) for the first time in 1997. The protected natural area of the hills of Almatret was included in the Plan of Areas of Natural Interest (PEIN) in 2000, and as a Special Protection Area for Birds (SPAB), in 2005; later it was included in the Natura 2000 network in 2006.
FLORA AND VEGETATION
The potential natural vegetation that covers a large part of the hills of Almatret corresponds to maquis formed of Kermes oak, blackthorn and white pine. Currently, however, this maquis has been significantly disturbed and is occupied by scrubland of basophilic weeds, dry meadows, bushes and patches of pine forest with maquis. Standing out among the basophilic thickets are those of rosemary and Linum suffruticosum, and those of rosemary with sage-leaved cistus (Genisto-Cistetum clusii).
In the darkest hollows we would find remains of coastal maquis with strawberry trees and Viburnum tinus.
In the driest and thinnest soils the bushes form mosaics with Mediterranean false brome thickets; in the clay hollows are the Calcicolous Aphyllanthes grasslands, and on the ridges, communities of black juniper with steppes. On the other hand, in the pastures we can find fragments of scrubland of Mediterranean saltwort and yellow restharrow (Salsolo-Artemisietum herba-albae). Finally, on the edges of the Ebro there are isolated patches of reed swamps and riparian forest, with willows and poplar trees.
The reed swamps (Typho-Schoenoplectetum glauct) occupy the lower parts of the Almatret Natural Area and, more specifically, the banks of the river Ebro. These formations are on the shores of the reservoir where the slopes of the ravines are less pronounced. Within these communities, the reed is the dominant plant, while the other characteristic species are less abundant. The importance of the reed lies in its filtration capacity, sediment retention and as a refuge point for the ornithofauna.
There are also endemic and rare plants of our flora such as the Genista biflora, Digitalis obscura, Veronica tenuifolia or Teucrium aragonense.
And numerous aromatic and medicinal plants such as thyme (Thymus vulgaris),rosemary (Rosmarinus officinallis) and others such as Atriplex halimus, Mediterranean saltwort (Salsola vermiculata) and Mediterranean ephedra (Ephedra nebrodensis)grow here.
The main function of the protected natural areas of Catalonia is to conserve representative samples of the fauna, flora and habitats of the territory, so that ecological processes that give rise to biodiversity can be developed. That's why in the hills of Almatret we can find a wide variety of fauna and species, among many groups of animals.
As for the fauna, the coasts of the Ebro and the Segre-Cinca-Ebro lagoon are a good refuge for the threatened Bonelli's eagle (Hieraaetus fasciatus) and other raptors, including a colony of vultures. When the mountains enter the waters of the Ebro and with a relict riverside forest, there are other wildlife of great interest: otters, water turtles and aquatic birds are of particular interest. Regarding fish, the freshwater blenny (Blennius fluviatilis) is the only native species that has survived well in the reservoir and after the introduction of all kinds of native species for sport fishing. Thus, the diversity of aquatic animals that inhabit the area range from fishing birds to otters, but also carp and sheatfish, can also be found after being introduced and nowadays are considered invading alien species.
With respect to birds, we can find an extensive variety of perching birds, eagles, kestrels, vultures, Egyptian vultures, kites...
Among the terrestrial animals, there are mammals, such as wild boars, roe deer, rabbits, hares, foxes, badgers, stoats, hedgehogs, rats, mice, moles and a variety of bats, such as lesser horseshoe bat . Regarding the most common reptiles in the area, we see the eyed lizard, snakes such as vipers or ladder snakes and Montpellier snakes, lizards, Moorish geckos and amphibians such as toads, frogs and Spanish pond turtles.
Vultures, short-toed snake-eagles, Eurasian eagle-owls, kingfishers, thekla-larks, black wheatears, whitethroats, long-tailed tits.
Steppe birds depend on very special conditions to obtain shelter and food. The natural area of the hills of Almatret meets these conditions and is therefore a reserve for some specific bird species that can only be found in these dry lands in Catalonia. This area is part of the Natura 2000 network and is a Special Protection Area for Birds (SPAB).
In this SPAB, the species designated as priority are the European roller, the calandra lark and the lesser kestrel. Also to be found are the short-toed lark, hen harrier and the stone-curlew.