The Ribeira dos Manueis is a tributary of the left bank of the Sado River and rises in the eastern slopes of the Serra de Grândola. In the territory of Abela, it becomes known as Ribeira de Corona. On the left bank of this stream is the village of Abela, the main parish crossed by this watercourse from west to east. It is a small stream whose flow is completely dependent on winter rains, with only a few areas with small pools (puddles) remaining in the summer where there are springs.
The importance of this stream and the fertile soils around it is evidenced by numerous archaeological finds, such as the 'Insculptured Stele of a Bronze Age Warrior' in Herdade das Pereiras - São Bartolomeu da Serra, which is currently in the Municipal Museum of Santiago do Cacém.
The biodiversity in Ribeira dos Manueis, while not naturally identical, certainly has many common points with that of the Sado River, so we can find the following species there:
FLORA
Willows (Salix sp.), poplars (Populus), oleander (Nerium oleander), cattails (Thypha domingensis), bramble (Rubus ulmifolius), rush (Juncus effusus), nut sedge (Cyperus esculentus), spurge flax (Daphne gnidium), various shrubs.
FAUNA
Fish - carp (Cyprinus Carpio), barbel (Barbus barbus), Iberian chub (Chondrostoma lusitanicum), bordalo (Squalius alburnoides) appears in spring, pumpkinseed (Lepomis gibbosus), pike (Esox Lucius), catfish or wels catfish (Silurus glanis), black bass (Micropterus salmoides), and bleak (Alburnus alburnus), these three species may have been introduced. Spanish toothcarp (Anaecypris hispânica), European eel (Anguilla anguilla), and mullet (Mugilidae) - (they go up the river near Moinho da Gamita, near the source of Vale da Eira, in the parish of Ermidas-Sado). The effects of the tide are felt up to Santa Margarida do Sado. The migration of mullets is certainly not unrelated to this fact).
Fishing
Fishing was done with nets (gillnets and traps), with rods, lines, and hooks (this type of fishing is still practiced today).
Birds
Kingfisher (Alcedinidae), reed warbler (Acrocephalus scirpaceus), common buzzard (Buteo búteo), sparrowhawk (Accipiter nisus), kestrel (Falco tinnunculus), mallard (Anas platyrhynchos), blackbird (Turdus merula), European bee-eater (Merops apiaster), chiffchaff (Phylloscopus collybita), golden oriole (Oriolus oriolus), moorhen (Gallinula chloropus), white stork (Ciconia ciconia), black stork (Ciconia nigra), raven (Corvus), barn owl (Tyto alba), tawny owl (Strix aluco).
Other animals
Eurasian otter (Lutra lutra), red fox (Vulpes vulpes), European badger (Meles meles), Egyptian mongoose (Herpestes ichneumon), viperine snake (Natrix maura and Natrix natrix), ocellated lizard (Lacerta lepida); fire salamander (Salamandra salamandra). Other common animals that can be found are the common genet (Genetta genetta), wild boar (Sus scrofa), Cetti's warbler (Cettia cetti), Eurasian blue tit (Cyanistes caeruleus), blackbird (Turdus merula).
The Louisiana crayfish (Procambarus clarkii) was introduced here in the 1980s. It is a highly harmful species to fish and amphibian communities as it feeds on tadpoles and young fish.
Mediterranean turtle (Mauremys leprosa) - it is the most common turtle in freshwater systems south of the Tagus River.
European hedgehog (Erinaceus europaeus) - a small mammal belonging to the insectivorous order and the family Erinaceidae. It is easily identifiable by the fact that it is the only mammal in the Portuguese fauna with a body covered in modified spines. The areas of the body without spines have a yellow-brown color.
Distribution: Throughout the national territory and most of the European continent.
Curiosities: The European hedgehog is a species that hibernates throughout the winter, for which it has internal adaptations. This species has an omnivorous diet, consisting mainly of insects such as beetles, spiders, and ants. It can also feed on small rodents and birds, as well as some fruits and mushrooms.
Greater white-toothed shrew (Crocidura russula) - One of the typical micromammal species of montado areas. Shrews differ from other micromammals due to their carnivorous diet (insects), and their teeth are adapted for this purpose (very sharp to pierce the shells of insects). As the name indicates, this species is distinguished from other shrews by its white-based dentition. It has a pointed nose and very small eyes due to its nocturnal habits, with smell being its main sense of orientation.
Curiosity: the offspring accompany the mothers in hunting, following in a line (each one grabbing the tail of the next).
Egyptian mongoose (Herpestes ichneumon) - Probably introduced to the Iberian Peninsula by the Arabs, the Egyptian mongoose is the only diurnal mammal in our fauna. Of medium size, with dark brown fur and elongated body, it is easily identifiable by its long tail with hair only at the end. Egyptian mongooses form family groups, and it is common to see more than one individual.
European otter (Lutra lutra) - otters have evolved to thrive in aquatic systems. Therefore, they have interdigital membranes between their toes to aid in swimming and a hydrophobic coat. They form family groups and are usually seen swimming in groups.
Distribution: Throughout the national territory and most of the European continent.
Curiosities: The otter has no known natural predators, making it the top of the food chain.