A significant part of the available data on the natural history of Socotra dates back to 1880-90ths expeditions.
In 1880 the British Association for the advancement of Science put aside £100 for "taking steps for the investigation of the Natural History of Socotra" and launched a first scientific expedition led by Prof. Isaac Bayley Balfour (1853-1922). The team reached Socotra on 11th February 1880 and spent 48 days on the island making zoological, geological and above all botanical collections. The latter resulted in a first detailed botanical account of the island with a description and illustration of over 200 species and 20 genera new to science in Balfour's "Botany of Soqotra" (1888). An account of the recorded animals was given in 1881 by BLANFORD, BUTLER, GODWIN-AUSTEN, GÜNTHER, SCLATER & HARTLAUB and WATERHOUSE.
Balfour's visit was followed one year later by an expedition of two German naturalists. Dr. Georg August Schweinfurth (1836-1925) and Dr. Emil Riebeck (1853-1885), who spent six weeks on Socotra in April/May 1881. Beside studying the people and their language, they investigated also the flora and fauna of the island. The plants collected were included by Balfour in his Botany of Socotra and the faunistic data were published by MARTENS 1881, HARTLAUB 1881, PETERS 1882 and TASCHENBERG 1883.
Dr. Theodore Bent (1852-1897), accompanied by his wife Mabel, who where archaeologists, made a collection of plants whilst studying the archaeology of Socotra for two months in 1896/97. They were accompanied by E. N. Bennett, who scaled some of the mountain peaks for the first time and collected a greater number of animals, mainly arthropods (DIXEY et al. 1898).
The first specifically and more complex zoological survey was led by W. R. Ogilvie-Grant (1863-1924) from the British Museum London and H. O. Forbes (1851-1932) from Liverpool Museum. They reached the archipelago on 3rd December 1898 and spent about three months there. Beside Socotra they visited also Abd al Kuri. Their records were summarised by FORBES (1903) in his famous monograph "The Natural History of Soqotra and Abd al Kuri".
On behalf of the Vienna Academy of Sciences an Austrian expedition went to South Arabia and Socotra in autumn 1898. The team included the linguist Prof. D. H. Müller, Dr. S. Paulay (1839-1913), the ship's surgeon with special interest in Botany, the geologist Dr. F. Kossmat (1871-1938), Prof. Oskar Simony (1852-1915) a Professor of Mathematics and enthusiastic Entomologist, and Dr. A. Jahn, another linguist. The five scientists landed at the West coast of Socotra, near Ghubbet Shoab, on the 8th January 1899. For about two months they worked mainly on Socotra, but visited also Samha and Abd al Kuri, with important results in various fields. Kossmat put together complex and basic geological data, while Paulay and Simony saved an extensive collection of plants and animals. Among the recorded animals brought back by the expedition to Vienna were about 4000 insects (of about 500 species), and about 400 reptiles and fishes of 70 species. The geological and biological results were published in a special volume (71 I & II) of the Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften (STEINDACHNER 1903; KOHL, KRAUSS, VIERHAPPER 1907; BECKER, REBEL 1931 / The Halbband II of Band 71 was published 1931, but the paper it contains were delivered much earlier to the Academy).
After these major activities it was over half of a century until Socotra was again subject of a biological survey. It was carried out by the British entomologist Dr. George Basil Popov (1922-1998) who undertook a study on locusts for the Desert Locust Survey Nairobi. As a result of his ecological investigations he published an excellent view on the Saltatoria fauna of Socotra, and a first systematic description of its vegetation (POPOV 1957, UVAROV & POPOV 1957, POPOV 1959).
The University of Oxford Expedition of 1956, led by Douglas Botting (b. 1934), aimed to carry a general scientific reconnaissance (BOTTING 1958). In the party of six men was the British tropical ecologist Dr. Michael Gwynne (b.1932) who made biological collections and produced a first vegetation map of Socotra (GWYNNE 1968).
There were occasionally small biological collections by members of the British Army who visited the island during the next few years, but most important in this period was the Middle East Command Expedition in the spring 1967 (DOE 1992). The collection of plants were made by the two Botanists Alan Radcliffe-Smith (b.1938) from the Royal Botanic Garden Kew and John Lavranos (b.1926), while the zoological records were done by the British entomologist Kenneth Guichard (b. 1914).
After the withdrawal of the British from Yemen in 1967 Socotra remained for a number of years virtually closed to foreigners and further scientific exploration. Even Thor Heyerdahl and his international crew received no permission to land during their adventurous voyage with the reed boat "Tigris", in 1977.
In 1982 the geographical and biological departments of the University of Aden sent a scientific mission to Socotra, which can be considered as the start of Yemens national research activities on the island (WRANIK et al. 1986) (Fig. 19).
In the 1990's several missions were fielded with the participation of UNESCO, FAO and specialised national and international environmental, ecological and natural resources groups, such as the Royal Botanic Garden Edinburgh (ALEXANDER & MILLER 1996), BirdLife International (OSME Survey 1993; PORTER et al. 1996), Aden University and the Yemen Ministry of Agriculture, or Rostock University in cooperation with the Museum für Tierkunde Dresden (WRANIK 1998).
These activities have brought a wealth of information documenting different aspects of the islands environment. The floristic surveys already allow a detailed description of the flora and vegetation of Socotra to be made. In comparison little is known about the ecology, distribution and population size of the majority of animal species, so that the existing data are insufficient to develop a comprehensive assessment of the islands fauna. This, in turn, creates severe problems for a well-prepared protection strategy. Undoubtedly, there is still a definite need for further field surveys.