Floristically, they represent the northern limit of Mediterranean, Balkan and Pontic species, the southern limit of the central European and Caucasian species, and the western limits of a number of Asiatic species.

All of the forest plant communities in the area are considered rare at the European level. Certain floristic associations create unique communities which are only found in this part of the world (e.g. a Gymnospermo-Celtetum association). These mountains conserve plant communities and endangered or representative species, many of them endemic, for the bio-geographical unit of the Dobrudja Plateau. Plant species numbers for this region vary between 1779 and 1911 depending on the reference. This represents over 19% of European flora and is comparable to the rich flora of the islands of Crete or Corsica.

One of the main arguments for the establishment of this park area, and part of the remarkable ecological value of these mountains is the presence of a high number (>72) of threatened species of flora of both national and international status. 1.4% of these species are now considered to be probably Extinct, 17% Vulnerable or Rare, and 82% Rare (as per the Red Book listings). An example of the importance of this area at the community-ecosystem level is that of the Dobroudjan beech-hornbeam forest, which is unique to Romania. Another example at the species level is that of Campanula romanica (the Romania Bell), with the proposed Macin park area being the only park in the world that can offer protection to this species, endemic to this region alone. In all, this area supports 27 endemic plant species. However, it is recognized that data is poor and there may be many more species present than so far recorded. Dobroudja is the only Romanian region where there are still important areas of specialized steppe vegetation and these do not occur in other parts of Romania or elsewhere in the Balkans. The Macin Mountains represent the only national park of the country which protects this type of vegetation which is now very rare in Europe. The park would therefore be the only park in the world that conserves the specific habitats, plant communities, endemics, sub-endemic and relict species of the Dobroudja plateau, an internationally important and recognized biogeographic area.

Despite the unique nature of the biogeography of the Macin Mountains with their special floral and faunal attractions, information on faunal diversity is sparse. Of the 187 bird species sightings recorded within the park area, 60% (approximately 112 species) are listed by IUCN as either Vulnerable to Rare, or Possibly Extinct, with many of the remaining species being considered as Insufficiently Known. The Macin Mountians is the most important nesting are in Dobroudja for raptors and also represents an important migratory stopover site for raptor migrants.

Out of the 41 recorded mammal species, 11 are protected by international conventions. There are over 979 recorded species of lepidoptera, and a recent entomological expedition to the Mountains recorded 14 new species for Romania and 3 new species to science.

There are 7 strictly protected amphibians and all the eleven reptile species recorded in the Macin Mountain area are also strictly protected under the Bern Convention.

These communities and species are not found in the other parks or protected areas within or beyond Europe. Without this park, global biodiversity protection would be incomplete. The international biodiversity value of these ecosystems in the Macin area is without question.
Information gathered from the National Park oficial site: www.muntiimacin.ro