Читать книгу The Terrestrial Macroinvertebrates of the Sub-Antarctic Iles Kerguelen and Ile de la Possession - Maurice Hulle - Страница 12

Introduction

The Îles Kerguelen and the Îles Crozet belong to the “Terres Australes et Antarctiques Françaises” (TAAF). They are located in the South Indian Ocean Province. They were discovered in 1772 respectively by Yves Joseph de Kerguelen de Trémarec and Marc-Joseph Marion Dufresne whose first mate, Julien Crozet, had landed on Île de la Possession (Delépine 1995).

After their discovery, these islands remained untouched by any human presence until the whalers and the sealers visited them during the 19th Century and the beginning of the 20th Century. In 1924, they were officially attached to France, who only installed permanent bases there in 1950 on the Îles Kerguelen (Port-aux-Français) and in 1963 on Île de la Possession (Base Alfred Faure).

The history of fauna and flora is affected by the history of human visits. Fauna and flora were originally composed of a small number of native sub-Antarctic species. The first introductions of alien species occurred as early as the 19th Century (rabbits and dandelion in 1874). The number of introduced species increased significantly from the mid-20th Century, and now makes up approximately half of the species present. Some of the introduced species have become invasive. Given the small number of native species and the quantitative importance of introductions, terrestrial ecosystems have been severely disrupted by these invasions, especially as global warming has also caused significant changes in vegetation cover.

Assessing the impact of introduced species on native ecosystems and deciphering the interactions between native and alien species are some of the issues currently being investigated by scientific teams.

Until now, there has been no work presenting all the invertebrate fauna of these islands. Here, we are only considering macroinvertebrates (earthworms, mollusks, spiders and insects) from the Îles Kerguelen and Île de la Possession for which we have an almost complete knowledge. Other groups such as springtails, mites and tardigrades are still undergoing a taxonomic revision.

In the first part, we present the general characteristics of the Îles Kerguelen and Île de la Possession: their geography, their climate and their main landscapes, which constitute the environment and the habitats of terrestrial invertebrates. We also dedicate a paragraph to the first scientific discoveries that marked the knowledge of the natural history of these islands, then briefly mention the current scientific themes concerning invertebrates, as well as the measures of protection that have been put in place since the creation of a natural reserve in 2006.

In the second part, we present all species of macroinvertebrates. For each one, we evoke its status: endemic for the species found only on one of the two archipelagos, native for those present on other islands of the South Indian Ocean Province or other sub-Antarctic provinces, introduced for naturalized alien species and finally transient for species observed regularly but who are not reproducing on the islands. We also give information on known distribution, identification and elements of ecology. For the Archipel Crozet, we only present the fauna of Île de la Possession because the other islands have not been sufficiently explored to have such a thorough knowledge of the species.