The Guadaiza River rises at an altitude of 1,250 metres in Benahavís, near the crossroads with Istán and Parauta and on the southern slopes of Cerro Abanto, in the heart of the Sierra Trincheruelas. It is another of the several channels sprawling the coastal mountain ranges from Marbella to Manilva in a hydrological network the shape of a comb, perpendicular to the coast and composed of numerous rivers and streams of sloping, short route and sporadic contributions. The first 13.1 kilometres are part of the Sierras Bermeja y Real Special Area of Conservation, with the remaining 9.1 kilometres a part of the Río Guadaiza SAC until it reaches the Cortijo Blanco beach in Marbella. This Natura 2000 Network space connects the coastline to the interior mountain ranges, an ecological corridor of high environmental and landscape value, host to natural habitats and species included in the 1992 Community Directive, warranting its current listing as a SAC.

Almost 1.5 kilometres of its course is classified within the outstanding river space of the Guadaiza River, which also includes another 11.9 kilometres of the same river towards its headwaters; all this thanks to the magnificent degree of hydrological and geomorphological conservation, the importance of its vegetation and the ecological value it holds. To the north there is a predominance of forest use on both banks, with good coverage of both tree and shrub strata, and the quality of the riverbed being as good as it is in the middle section. In the last part of its stretch, the banks are used for urban purposes or for crops or wastes, leading to a change that becomes more evident upon approaching the river mouth.

Specific flora species have been relevant at the time of their recognition as SAC. One of them being the “gálio de flor verde”, a plant endemic to the southern peninsula, commonly found on the serpentine and peridotitic soils of the Guadaiza in its upper and middle sections. However, the primary objective of protecting this river ecosystem is the conservation of the sedentary otter population, found around the surface currents that drain the Sierras Bermeja and Real into the sea.

The SAC also has other environmental values. To the north it constitutes a potential wintering area for the black stork, with the egret and great egret also having the status of winterers. Other birds such as the common bittern and the kingfisher are equally deserving of recognition, which as its name indicates, feeds on the ichthyofauna that populate these waters. Fish are an important resource in the SAC, with species uncommon in other rivers, perhaps the most vulnerable being the freshwater blenny, which is accompanied by Andalusian barbel, eel, Pseudochondrostoma willkommii, Squalius carolitertii and the Squalius valentinus from Malaga (the latter an endemic species of rivers west of the province).

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There are bats with breeding colonies in the SAC, such as greater, Mediterranean and Mehely's horseshoe bats and Daubenton's bat, and the Spanish painted and Mediterranean tree frogs also stand out, as well as the Mediterranean turtle. In the rich and varied world of invertebrates, there are two species of dragonflies that give the area real value. One of them is considered a very good indicator of well-preserved river sections, where significant alternations in terms of water contamination or bad state of vegetation is rarely found. The marsh fritillary butterfly joins the cast of unique insects that can be found in this environment.

Habitats of community interest in the protected territory, such as the riverine forests featuring shrubby willows (Salix pedicellata), along with formations generated from thermo-Mediterranean (lowland) riparian scrublands, in which shrub and herbaceous species associated with lowland oleanders and widely dispersed tamarisk with perennial pastureland appear. The habitat characterised by Mediterranean marshland with tall grasses appears in the form of reed beds and areas of dense Mediterranean grasses, settled on flooded serpentine soils and subject to summer droughts.

The Guadaiza River does not support such intense public use as its neighbour Guadalmina, but current trends mean that some visitors do come for water sports, leisure and recreational activities. If you do decide to enter or use the river, please use previously disinfected shoes, clean clothing and utensils, so as not to transmit fungi or pathogenic microorganisms from other places. Take the utmost care not to alter the riverbed or its surroundings, else you risk damaging the habitats of otters and other living creatures. This is their home and there is no way to restore it once it has deteriorated. Please use the area respectfully, especially during breeding season, by informing yourself of the limitations or prohibitions that may be applicable.

The mouth of the river, being in a heavily used beach area, has virtually no trace of the natural vegetation associated with the riverbed, and has little importance from an environmental point of view. Nevertheless, it is still a SAC, so you must act in accordance with its status as a protected area.