The 2250 species of flora in Saudi Arabia are important in maintaining the integrity of their ecosystems.
Seventy six of 98 mammals species recorded from the Arabian peninsula occur in Saudi Arabia. The lion has become extinct recently; Cheetah and Saudi dorcas gazelle are probably extinct at present. Arabian leopard is believed to be endangered. The Arabian Oryx became extinct in the wild in the 1970's. Captive bred and re I-introduction species include the Arabian Oryx and two gazelle species (reem and idmi)

444 bird species have been recorded in Saudi Arabia, of which 10 are endemic and 185 breed in the Kingdom. The country is ecologically significant for flying visitors from Asia , Europe and Africa
Tidal flats of the Arabian Gulf are among the most important overwintering areas. They are home to 1-2 million waders of 125 species..

Mountain Biodiversity

A Thousand years ago the mountains of the Hijjaz and Asir were much more densely covered with woodlands with only remnants, estimated at 2.7 million hectares, still remain in the remote inaccessible areas. 
Juniper woodlands are one of the few densely wooded habitats in Saudi Arabia. they thrive at altitudes of 2000 - 3000 meters, and are characterized by some of the highest species diversity and biomass in Saudi Arabia. They are important for the production of orographic rain and for the preservation of soil integrity. They are also the biotope most favored by Saudi citizens for the nature related tourism.

A dieback phenomenon has been reported in the junper woodlands of Arabia and is a matter of concern. Available evidence indicated hydrological and/or climatologically cause. 

There are also olive woodlands on slopes that are 1500 - 2000 meters high that contain a number of other species. In addition to the mountain woodlands there are the arid woodlands , which are primarily acacias scattered nationwide in lower altitudes.

Marine Biodiversity

Saudi Arabia has 2500 kilometers of coastlines along the Red Sea and the Arabian Gulf. The Red Se is one of the deepest regional seas (reaching 2500 meters) while the Arabian gulf is shallow and almost land-locked sea. Both , described as "rainforests of the sea and an underwater paradise", play s strategic and fundamental role in providing the Kingdom with fresh water from desalination plants as well as fishes. The coastal environment is of a high recreational value. 

Coral reefs are famous for their beauty and 250 species of Red Sea coral have been recorded. They are less extensive in the Arabian Gulf and occur around offshore islands and in other patches. Coral reefs provide shelter and food for marine life, particularly fishes.

Over 1280 species of fish have been recorded in the Red Sea and 542 species in the Arabian Gulf. 
Seagrass beds and algal flats are among the most productive of the global ecosystems. Eleven species of all the seven known genera of seagrass occur in Red Sea. There are three species in the Arabian Gulf.

Seagrass have a fundamental role in primary production and main tendence of fisheries as feeding and breeding grounds. Beds of seagrass are also important for coastal stabilization and as an essential habitat for the endangered dugong and 5 species of marine turtles.

Arid Biodiversity

The 2250 species of flora in Saudi Arabia are important in maintaining the integrity of their ecosystems.
Seventy six of 98 mammals species recorded from the Arabian peninsula occur in Saudi Arabia. The lion has become extinct recently; Cheetah and Saudi dorcas gazelle are probably extinct at present. Arabian leopard is believed to be endangered. The Arabian Oryx became extinct in the wild in the 1970's. Captive bred and re I-introduction species include the Arabian Oryx and two gazelle species (reem and idmi)

444 bird species have been recorded in Saudi Arabia, of which 10 are endemic and 185 breed in the Kingdom. The country is ecologically significant for flying visitors from Asia , Europe and Africa
Tidal flats of the Arabian Gulf are among the most important overwintering areas. They are home to 1-2 million waders of 125 species..

Wetlands Biodiversity

Natural freshwater wetlands are the most vulnerable, of the key biological sites in arid landscapes of Saudi Arabia including ponds, streams and springs, as well as artificial wetlands such as reservoirs and effluent streams outside urban areas and agricultural developments. They attract and support a diverse assemblage of plants and animals and are important centers of endemism 

Mangrove are widely scattered along the Red Sea and Gulf coasts. There are two species: Avicennia marina is the most common in both coasts while Rhizophore mucronata is found in only eleven sites in the Red Sea coast.

Broad inter-Tidal flats and sandy /rocky beaches are important for turtle nesting, fishing and recreational activities. Sub-Tidal habitats are of special important because they generate much of the energy in the coastal ecosystems. 

Sand and Mud Flats are widely distributed, especially in the Gulf covering about 95% of the sub-tidal zone. Algae and invertebrates, account for the greates biomass in these large areas of relatively low productivity. Shrimp harvests are an important economic activity.

Protected Areas Biodiversity

Protected areas in Saudi Arabia (15 in number represent 4% of the country's area) server as in-situ seed banks that are strategically located for regeneration of overgrazed rangelands. A system of 103 protected areas that cover 10% of the country's area is planned and being considered.

They are important for conservation of biological diversity by protecting the existence of viable populations of key taxa of flora and fauna (hot spots).

These areas represent species historical distribution as well as their continued existence through re introduction programs.