Question: In what year was the Réserve Naturelle Lomako Yokokala established to protect various endangered chimps?

Context paragraphs:
La Désirade National Nature Reserve: La Désirade National Nature Reserve (French: "Réserve naturelle nationale de La Désirade" ) is a reserve in Désirade Island in Guadeloupe.  Established under the Ministerial Decree No. 2011-853 of 19 July 2011 for its special geological features it has an area of 62 ha .  The reserve represents the geological heritage of the Caribbean tectonic plate, with a wide spectrum of rock formations, the outcrops of volcanic activity being remnants of the sea level oscillations.  It is one of thirty three geosites of Guadeloupe.

Grand Cote National Wildlife Refuge: The Grand Cote National Wildlife Refuge (French: "Réserve Naturelle Faunique Nationale du Grand- Côte" ) was established in 1989 as part of the North American Waterfowl Management Plan.  It is a 6000 acre reserve located in Avoyelles Parish, near Marksville, Louisiana, in the United States.

Nature Reserve of Saint Bartholomew: Nature Reserve of Saint Bartholomew (Réserve Naturelle de Saint-Barthélemy) is a nature reserve of Saint Barthélemy (RNN 132), French West Indies, an overseas collectivity of France.

Réserve Naturelle Lomako Yokokala: The Lomako Forest Reserve is found in Democratic Republic of the Congo.  It was established in 1991 especially to protect the habitat of the Bonobo apes.  This site covers 3,601.88 km² 

Guadeloupe National Park: Guadeloupe National Park (French: "Parc national de la Guadeloupe" ) is a national park in Guadeloupe, an overseas department of France located in the Leeward Islands of the eastern Caribbean region.  The Grand Cul-de-Sac Marin Nature Reserve (French: "Réserve Naturelle du Grand Cul-de-Sac Marin") is a marine protected area adjacent to the park and administered in conjunction with it.  Together, these protected areas comprise the Guadeloupe Archipelago (French: "l'Archipel de la Guadeloupe") biosphere reserve.

Carrière des Nerviens Regional Nature Reserve: The Carrière des Nerviens Regional Nature Reserve (in French "Réserve naturelle régionale de la carrière des Nerviens") is a protected area in the Nord-Pas-de-Calais region of northern France.  It was established on 25 May 2009 to protect a site containing rare plants and covers just over 3 ha .  It is located in the municipalities of Bavay and Saint-Waast in the Nord department.

La Tortue, Saint Barthélemy: La Tortue ou l'Ecalle or Île Tortue is a small rocky islet off the northeastern coast of Saint Barthélemy in the Caribbean.  Its highest point is 35 m above sea level.  Referencing tortoises, it forms part of the Réserve naturelle nationale de Saint-Barthélemy with several of the other northern islets of St Barts.

Céreste: Céreste (Occitan: "Ceirèsta") is a commune in the Alpes-de-Haute-Provence department in southeastern France.  It is known for its rich fossil beds in fine layers of "Calcaire de Campagne Calavon" limestone, which are now protected by the Parc naturel régional du Luberon and the Réserve naturelle géologique du Luberon.

Bonobo: The bonobo ( or ; "Pan paniscus"), formerly called the pygmy chimpanzee and less often, the dwarf or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus "Pan"; the other is "Pan troglodytes", or the common chimpanzee.  Although the name "chimpanzee" is sometimes used to refer to both species together, it is usually understood as referring to the common chimpanzee, whereas "Pan paniscus" is usually referred to as the bonobo.

Île Fourchue: Île Fourchue, also known as Île Fourche is an island between Saint-Barthélemy and Saint Martin, belonging to the Collectivity of Saint Barthélemy.  The island is privately owned.  The only inhabitants are some goats.  The highest point is 103 meter above sea level.  It is situated within Réserve naturelle nationale de Saint-Barthélemy.

Supporting paragraphs: Réserve Naturelle Lomako Yokokala Bonobo
Answer: 1991