Nosy Komba

Nosy Komba (lit. "island of lemurs"), also known as Nosy Ambariovato, is a small volcanic island in Madagascar, situated between the island of Nosy Be and the northwestern coast of the main island of Madagascar. Roughly circular, it rises sharply towards a plateau and the summit of Antaninaombi at the center of the island. The lowlands of the island are divided between secondary forest and a patchwork of farmland and plantations (notably including shade-grown coffee), while the highlands are mainly scrubland. Heavily deforested over the 19th and 20th centuries, only small pockets of old-growth forest remain in rural gullies and hills. The island experiences a heavy dry season typical of northwestern Madagascar, and is dotted by bamboo and Fabaceae trees, alongside the non-native mango and jackfruit. The island hosts a diverse range of reptiles and amphibians, although this has been slightly reduced by past deforestation. The island is known for its namesake black lemurs, an additional nocturnal species of lemur has not been sighted on the island since the 1990s.

During the early 19th century, the region was heavily settled by Sakalava refugees and their slaves fleeing the hegemony of the Merina Kingdom. France gained control of the island in 1840, and soon used it as a sanatorium retreat and as a center for their colonial labor force. The population of Nosy Komba, mainly restricted to the northern half of the island, relies on ecotourism and handicraft, supplemented by a wide range of agricultural products such as coffee, vanilla, cacao, and sugar cane. A number of hotels and guest houses support tourists to the island, mainly on short excursions from Nosy Be.

Geography
Nosy Komba is a small circular volcanic island 27.9 km2 in area, located 3 km south of the larger island of Nosy Be and 4 km north of Ankify, the nearest point of the main island of Madagascar. Nosy Komba's lowlands are largely divided between farmland and secondary forests, while scrub predominates in the highlands. All sides of the island steeply rise towards the central plateau. Antaninaombi, the summit of the island, reaches a height of 622 m.

Most of the island's population is located along the northern half of the island, with the south very sparsely populated. Ampangorina is the main village on the island. Cruise ships and pirogues connect Nosy Komba with Nosy Be.

The island formed during or shortly after the end of the Cretaceous period 66 million years ago, as Madagascar separated from the continent of Africa. The landmass consists of an igneous intrusion of gabbro and nepheline surrounded by schist.

History
In the early 19th century, the Merina Kingdom gained hegemony over the Sakalava-inhabited northwestern coast of the island. Merina persecution motivated several revolts and the migration of 15,000 Malagasy, mainly Sakalava and their slaves, to the islands of Nosy Be and Nosy Komba. Expanding French influence over the region forced the Merina Kingdom to cede Nosy Be and Nosy Komba to France in July 1840. Three years later, these placed under a local colonial administration titled Nosy-Bé et Dépendances. The island quickly became a center of the French colonial labor force. A large "hangar" housing over 800 workers was constructed on the island by the late 1850s, and was used to screen newly-recruited laborers; many died soon after reaching the island.

French settler-colonial efforts on Nosy Be were persistently hampered by outbreaks of diseases such as malaria, cholera, and smallpox. To remedy this, a convalescence retreat was built on the adjacent Nosy Komba in 1841, immediately following the French annexation of the region, with an upgraded facility constructed in 1876. The location of the retreat on Nosy Komba's highlands was motivated by 19th century beliefs in the healing effects of high-altitude environments, alongside the existence of ample colonial labor to support the European settlers. Laborers were used to carry European patients up to the summit from the lowlands. In 1895, this retreat was further upgraded into a full sanatorium following widespread malaria outbreaks among French colonial troops during the Second Madagascar expedition. Functioning as a "sorting station" for a variety of other medical facilities in northern Madagascar, it could house 500 patients at any one time. A total of 1,883 patients were treated at the facility over the course of 1895, with a mortality rate of 5.3%. The high mortality led to resident physician Jean Darricarrère labelling it a "sanatorium in name only". However, this was significantly lower than the mortality rate within the colonial troops on the main island. The island remained in limited use as a sanatorium, with ill colonists using it as a refuge from Nosy Be as late as 1928.

Flora and fauna
Alongside much of northwestern Madagascar, Nosy Komba is located within the Sambirano ecoregion. The heavy dry season characteristic of the region has led to the emergence of sclerophyllous plants.

The secondary forests covering much of the island are composed largely of Fabaceae trees and non-native fruit trees such as mango and jackfruit. Larger indigenous trees are only prevalent in small areas of the island. The central highland scrub is dominated chiefly by bamboo. No official environmental protections exists on the island itself, although it hosts a traditionally-protected area of around 45 ha of old-growth indigenous forest. During the colonial era, an arboretum was established in the highlands. Officially under the Ministry of the Environment and Forests, there is essentially no enforcement of environmental protection measures in the area; as such, it has been heavily damaged by continued logging in addition to natural damage incurred over time from tropical storms. The island is adjacent to the offshore Tanikely Marine Reserve, the oldest marine reserve in Madagascar. Nosy Komba hosts 41 known species of reptiles. These include six species of chameleon, six species of skink, two plated lizards, sixteen species of gecko, and eleven species of snakes. The island is also home to eleven species of frogs; these are the only known amphibians on the island. Although highly diverse for an island of its size, the level of diversity on Nosy Komba is significantly lower than the adjacent Nosy Be, which hosts twice as many frog species. Widespread deforestation over the 19th and 20th centuries likely contributed to this disparity. Some forest-dependent species may have only survived in small pockets of surviving forests along steep hills and valleys. Additionally, due to the island's small size, human activity alongside natural disasters such as severe storms may have had an intensified impact on local species. However, some species of reptile (notably the chameleon Calumma boettgeri) have experienced a considerable population rebound over recent decades. The patchwork of shade-grown coffee plantations and adjacent forests have functioned as refuges for many species of reptiles on the island.

In 1998, a research team discovered an species of liverwort endemic to the summit of the island, dubbed Cololejeunea nosykombae.

Lemurs
The island hosts a population of black lemurs. These are protected by local residents, although unlike some other areas within the lemurs' range, are not regarded as sacred animals. The Nosy Komba population of black lemurs was found to have a lower genetic diversity than the population on Nosy Be, and likely came from a population on the Ambato peninsula of the main island.

At least one species of the nocturnal sportive lemurs, the Gray-backed sportive lemur, previously inhabited the island. However, no confirmed sightings have been made since the late 1990s. A 2013 survey could not find any direct evidence of nocturnal lemurs on Nosy Komba. Some inhabitants of rural areas of the island testified to the continued existence of a nocturnal lemur colony near the summit of the island, and attribute the population decline to wildfires, deforestation, and the locally taboo practice of hunting the animals for bushmeat.

Economy
Tourism and the production of handicrafts are the main economic activities on the island. A wide variety of crops are grown on the island. Shade-grown coffee and cacao are grown in designated plantations, while other plantations grow crops such as cassava, chili, banana, pineapple, rice, sugar cane, teak, and vanilla. Fishing is also an important industry, especially in the village of Ampangorina.

Tourism
Like Nosy Be and many other small islands off the coast of Madagascar, Nosy Komba hosts a large number of hotels and tourist facilities, mainly catering to ecotourism. The largest on the island, Tsara Komba Lodge, consists of eight bungalows. The hotels are supplemented by around 13 guest houses which are privately rented out to tourists. Many of these facilities are designed to accommodate one-day stays for excursions from Nosy Be. Tourist infrastructure is limited to the coastal lowlands.