Biodiversity

Biodiversity in Numbers

Fauna and floristic diversity is very rich in the archipelagos of Macaronesia, but is smaller in the archipelagos geographically farther from the continents (Azores case), which is certainly related to distance, geological age and various historical events (eg, volcanism , human intervention) verified in each of the different islands.

In 2010, the total number of terrestrial species and subspecies (= taxa) in the Azores was estimated at 6164, of which 452 are endemic, corresponding to 7.3% of the total diversity. Note that these numbers are lower than those of the Madeira archipelago, estimated at 7571 land taxa, including 1419 endemic (19% of total diversity). However, it is believed that these values ​​are underestimated, given that there are terrestrial and marine species (known and still unknown to science) that could increase this number to about 10,000 species and subspecies.

However, arthropods (Filo Arthropoda, which includes crustaceans, centipedes and millipedes, mites, spiders and insects, among other animals) have the highest diversity (2332 taxa), representing about 42% of the species found in the Azores. Considering all fungi (including lichens) and seedlings (spermatophytes), they represent the second (24%) and third (18%) more diverse groups of organisms in these islands.

In the case of insects, the Azores have less specific wealth (1773 taxa) than Madeira and Selvagens (3297 taxa). In particular, the Odonata are represented by four confirmed species for the Azorean archipelago (two more sporadic) and six species for Madeira and Selvagens, none of which are specifically endemic to these archipelagos. However, Sympetrum nigrifemur is considered an endemism of Macaronesia, being present in Madeira and the Canary Islands. On the other hand, in the Azores lies a “biological jewel”, the damselfly Ischnura hastata, the only species of odonates in the World with parthenogenetic reproduction (exclusively female reproduction, in the absence of males.

The animals and the terrestrial plants are the groups with greater diversity in endemismos. Indeed, in the Azores there are at least 266 arthropods and about 80 endemic vascular plants (Pteridophyta and Spermatophyta).

As for arthropods, most of them are exotic (58%). On the other hand, more than 60% of the vascular flora of the Azores is considered as exotic, while mammals (except the two native bats), amphibians and reptiles were introduced.

Total number and proportion of species and subspecies of the various groups of fungi (including lichens), plants and terrestrial animals of the Azores archipelago (adapted from Borges et al., 2010).

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Biodiversity conservation

Environmental education facilitates knowledge about the environment, values ​​and competencies as well as the experience to act in the prevention of present and future environmental risks. In this regard, considering the number, degree and nature of the threats of many endemic and native plants, it is important to promote awareness-raising actions aimed at their protection, namely: control and / or eradication of invasive species; the limitation of the use of the ground by the cattle in zones of native vegetation; to avoid trampling plants outside tourist sites; increase of reduced stock populations, through their propagation elsewhere (e.g., nurseries); respect the populations of the endemic species of an island (s), since the exchange of individuals between islands can disturb the dynamics of evolutionary mechanisms.

Due to the rarity, there are three cases of endemicity associated with the animals. Among the many endemic insects of the order Coleoptera, blind beetles living in caves and volcanic cavities and those inhabiting hotspots with small areas (eg at Pico Alto, in Santa Maria) are of particular concern. At the level of the birds, the Pyrrhula murina, the only terrestrial endemic bird of the Azores, whose habitat is resting to the northeast part of São Miguel and whose population will be around 400-500 individuals, has been an example of important conservation measures. Also, the diurnal and harmless Azorean bat, Nyctalus azoreum, the only mammal endemic to the archipelago, should be protected to avoid the decline of its population and thus maximize the high predatory potential of insects that are harmful to the environment. agriculture and human health.

 

Virgílio Vieira

2018