Nisyros flora and fauna are of high interest thanks to their volcanic origin and geographical position.
In terms of flora, it constitutes a migration route of Asian species traveling to the Hellenic Territory and Southern Europe in general (in conjunction with other Aegean islands, particularly the ones close to the coastline of Asia Minor).

It is situated on the eastern migratory route of birds, being most significant for their migration to Greece and Asia Minor.
The recorded presence of 450 flora species, 85 avifauna species and 7 reptile species, as well as the presence of the Monachus-monachus seal on the coast of the island, make this 42,000 – acre island a place worthy of special protection and assessment.

The rich and dense vegetation, astivides (Sacropoterium spinosum), myrtle (Lavandula stoechas), cistaceae (Cistus creticus & Cistus salviifolius), thyme (Thimus capitatus), savory (Satureja thymbra) as well as the tall spanish brooms (Spartium junceum), daphne plants (Daphne gnidioides) and thorny brooms (Calicotome villosa) are only some of the pleasant obstacles that anyone venturing away from the paths will come across.

The presence of numerous trees is another special feature that classifies Nisyros as the sole “green” active volcano in the Aegean. A number of them constitute the island’s remaining self-sown vegetation, such as the Valonia oak (Quercus macrolepis), the Kermes Oak (Quercus coccifera), the turpentine tree (Pistacia terebinthus) and the wild olive tree (Olea europaea sylvestris).

Fossilized leaves belonging to the wild olive tree were discovered in layers of ash bearing testimony to its existence on Nisyros 60,000 years ago. Most of the trees that exist nowadays on Nisyros have been planted by man (olive, fig, almond, and turpentine trees).

The fauna which is present on the island is equally rich and varied as the flora, and provides pleasant company to the hiker during long walks. While walking on Nisyros, one cannot avoid making friends with the “kourkoutavli” (Agame stelio), the huge ashen grey lizards, which scurry to hide under the lava or in between the dry rock walls, the large spiders that block your path with their strong webs, the “cyani” of Aristotle  – the beautiful cyan-colored magpies (chalkokourouna) that are annoyed as you pass by them -, and the hawks continuously hovering in the sky.