The altitude and climate are factors that influence the richness of the municipality's fauna and flora. There is a great variety of endemic species, among them we can highlight the Edelweiss and the Lady's Slipper, a rare orchid included in the Catalogue of Threatened Species of Aragon.  

It is remarkable that in the territory of Sallent de Gállego we can find 35 species of orchids and as we have already said, among them we can highlight the Lady's Slipper (Cypripedium calceolus).  This species of orchid is one of the main floral attractions. It flowers between May and June. Only 7 populations are known in Spain, all of them in the Pyrenees, and the one in Sallent is the largest.

Among the vegetation it is worth mentioning the Selva de Sallent, a magnificent beech forest that in autumn is tinged with reddish colours and ends up losing its leaves in October, leaving a soft cushion that creates a magical environment for a stroll.
In the beech forest you can also find some shrubs such as boxwood, anayones or some graminoid grasses such as iris or beautiful liliaceae but to a lesser extent since the thick shade of the beech trees of between 20 and 30 metres hardly allows the sunlight to penetrate.


Above 1,700 metres, above the beech forests mentioned above, we find the black pine, as it is one of the few that can withstand the 0ºC isotherm (possibility of frost every month of the year), prolonged snowfalls from November to April and a great deal of sunstroke. This tree is characterised by a conical-pyramidal crown, with short, dark leaves that give the pine its name.
These environments are characterised by a dense undergrowth of rhododendron or anayones with the company of the occasional rowan or juniper.


Above 2,200-2,300 metres we find an area of isolated trees that try to survive in an adverse mountain climate, so at this altitude we will mainly find supra-forest pastures.
Since ancient times, livestock farming has needed to clear the forests to create more pastures. In this area, plots of land were set on fire to create these pastures, and the resulting piles of earth and ash were used to form what are known as "formigas", which were used as mineral fertiliser; this practice may have given Formigal its name.

Ascending to the altitude of the three-thousanders we find many high alpine and boreo-alpine mountain plants, which are snow-dwelling species that flower and disappear in the few weeks that these summits are free of snow, including, for example, the glacier buttercup that can be found on the Balaitus.

Finally, there is also a type of vegetation associated with the temporary wet areas produced by the thaw, these species are adapted to the lack of nutrients and oxygen, such as reeds, grasses or orchids.

In the area of the mule corral there are small populations of water clover, flycatchers, mountain mosses and water veronica.