Abstract
Large faunal species disappeared from Madagascar at a time when humans were certainly present on the island. A deduction, though not a parsimonious one, purported by many scholars is to attribute these extinctions to the hands of man, whether as a primary or contributory factor (e.g. Burney et al., 2003; Martin, 1984). By contrast, in Extinct Madagascar, Steven M Goodman and William L Jungers explore in greater depth than the current literature presently offers the recent past of these animals through specific case studies presented by sites and by species. Each site is splendidly illustrated by the artist Velizar Simeonovski in arresting artworks, depicting how some of these animals may have lived or gone extinct based on available palaeontological evidence. These plates allow the reader a pictorial (though still speculative) glance of the past.
In one of my favourite plates, a colony of elephant birds are nesting along the gentle coastal escarpment of Cap Ste Marie in southern Madagascar, where exceptionally high concentrations of egg debris have been found. Such high concentrations of egg debris for a large ratite species are surprising. Goodman and Jungers speculate that this could indicate an ancestral communal breeding system found in certain living ratites. But intriguingly, what could have caused the extinction of such a large breeding colony? Goodman and Jungers use the published literature about the deposits to suggest that the extinction occurred as recent as 750 yr BP but with little evidence to date of extensive human hunting of these birds in this region.
Perhaps the most provocative (or misleading) plate is a view of a hunter–gatherer settlement at Taolambiby in southwest Madagascar. While some people are butchering and roasting a suite of large extinct lemur species, others from a hunting party are bringing additional preys. The depiction, according to Goodman and Jungers, is based on the deposit of bones analysed from a palaeontological site at Taolambiby, where 40% of bones of the large extinct sloth-like lemur Palaeopropithecus and 33% of the large lemur Pachylemur show signs of butchering. Bones bearing evidence of butchery, in the form of cut-marks, have been commonly perceived as demonstrable human modification of faunal compositions. However, all of the claimed modified bones come from the palaeontological site at Taolambiby, and none of them are associated with any other evidence of contemporaneous human occupation. Goodman and Jungers argue that the lack of archaeological artefacts probably indicates that these hunter-gatherers did not live in permanent settlements or that the settlements have yet to be found. It is regrettable, according to the authors, that only a single radiocarbon date from the above mentioned species is available and dated to 2345 yr BP. According to the authors, the present evidence is not sufficient to purport the hypothesis of human-driven extinction at Taolambiby, and one can only wonder whether Simeonovski’s plate at Taolambiby is not rather misleading.
It has long been assumed that Madagascar’s highlands, a geographic area that represents a large proportion of the island, were once completely forested; this assumption is mainly based on the apparent poverty of species and endemism in the grasslands relative to the forested parts of Madagascar (e.g. Lowry et al., 1997). However, over the past years, researchers have proposed that grasslands are probably native to Madagascar, given the presence of endemic grasses, endemic shade-intolerant trees and endemic vertebrate and invertebrate grassland specialists (Bond et al., 2008; Goodman and Benstead, 2005). But whether the highland landscape was mostly ‘grassland’, or a ‘savannah with some woody component’, or ‘open wooded forest with some grassland component’, is still open for debate. In Extinct Madagascar, Goodman and Jungers examine the palaeontological sites in the highlands at Ampoza, close to the Isalo Massif, to illustrate that the highland was probably more of a mosaic vegetation. The fossil record from Ampoza gives two important clues to the more forested nature of the highlands: first, bones of the extant Indri, Indri indri, have been recovered. This lemur is known today only from the eastern humid formations. It is therefore very probable that pockets of humid forest were continuous with open woodland, which would have provided the means for strictly forest dwelling animals to disperse in the highlands. The second clue is the abundance of bones of the extinct Palaeopropithecus, which implies that the habitat at Ampoza would have been a closed forest as this sloth-lemur is considered as one of the most specialised suspensory mammals on Earth. Given that the bones have been dated between 2950 and 1830 BP, it implies not only the loss of those animals from the highlands but profound ecological changes in the highland landscape.
Extinct Madagascar provides superb information on a large number of palaeontological sites, contextualising the ecological uniqueness of each site. By examining such a large number of palaeontological sites individually, Goodman and Jungers bring us closer to the words of the late Robert Dewar (1997): ‘it seems less and less appropriate to expect a single, uniform cause for the extinctions will be ever found’. As the authors themselves described, the ‘jury is still out’ on determining a clearer picture of extinction processes. The material presented should certainly provide more ‘meat’ to pursue research on the elusive nature of past extinction processes in Madagascar, especially if the past is to be used as a guide to conservation of biodiversity. This is more relevant than ever, with the huge challenge facing biodiversity in Madagascar today with continuing climate change and increasing human population impacts.