The vegetation is quite diverse in view of the island’s size. There are mainly cedars, junipers, lentisc, thyme, heath and rockroses and sandy shore vegetation.
The Cedar forest of Chrissi is very rare in its expanse and structure. It covers almost 35 hectares and its density is approximately 28 trees per hectare. Their average height is 3 to 7m tall and their average age is at least 300 years old. Cedars have a root system that spreads across an area which is more than double the height of the tree. Apart from the big roots, a huge amount of tiny roots forms a complex web that keeps the sand in place.
The number of plant species of Chrissi is relatively high compared to its size, comprising 1/20 of the Cretan flora. Many species are rare and endemic, therefore protected by international directives and laws.
In the sea around Chrisi the variety and abundance of the marine species are impressive, as the water is shallow. The sea bed around the island up to a depth of 20m covers about 30km2 (area six times the size of the island).Most of the island’s animal species have a Mediterranean distribution. None of them pose any threat to humans.
The sea turtle Caretta caretta has been observed many times on the island, but without any records of nesting.
Up to now more than 120 species of birds have been reported, the vast majority of which are migrant species that find in Chrissi a place to rest and feed themselves for their long journey.In recent years the residents of Ierapetra transferred partridges, hares and rabbits. Hares have now become extinct and there is a systematic attempt to remove the rabbits.Some decades ago, when the Mediterranean monk seal (Monachus Monachus) was not threatened by man, it could be seen coming out of the water and basking in the sun, on the island’s beaches.
Today it rarely appears and mostly the name Fokiospilo (seal cave) on the northwestern coast reminds us of its once common presence.For the last centuries Chrissi was practically deserted, while much earlier there were small settlements. On the western and eastern part, broken pieces of pottery have been found, which shows activity during the Minoan times. In the northwest there is a chapel of Agios Nikolaos, possibly built in the 13th century. Northeast of the chapel and near the shore there is an even older salt pan and the only house on the island, which is built on ancient ruins that include a small building and a small port. South and southwest of Agios Nikolaos there are some wells and a few carved graves. The largest one dates from the Roman times.