Moist savanna (hereafter called savanna), as defined in this EAP is more encompassing than the IUCN definition of this habitat. In the context of this assessment it is defined as, “open areas dominated by grasses, sedges and herbaceous herbs and occur where the local hydrology is such that it does not allow the development of a tree or shrub layer resulting in savanna-like open areas” [1]. This native habitat has tracts greater than 0.1 km2 on 16 of the 55 islands of the archipelago. Prior to human arrival savanna may have been more extensive, especially on islands that had native habitats cleared for coconut Cocos nucifera L. plantations, though evidence for this is anecdotal. Savanna covers 14.6 km2 of the terrestrial landmass (c. 2.9% of the total landmass of the archipelago). It is a critical habitat for terrestrial nesting seabirds and supports ≈ 200,000 breeding pairs annually, > 70% of the total number of pairs of seabirds breeding in the archipelago [2]. The guano of breeding seabirds has been proven to benefit multiple ecosystems both terrestrial and marine [3]. It is also important habitat for native invertebrates, particularly Orthoptera and Lepidoptera. There is realistic scope to increase (or regain) the acreage of savanna in the Chagos Archipelago that would have benefits to multiple taxa in other ecosystems.