Right now one of the biggest threats facing both the Hispaniolan solenodon and hutia is our lack of knowledge. We know very little about the species’ biology and ecology, in addition to only being able to guess at the factors that are impacting on their populations. Although we need to do more research into their distribution, abundance and habitat associations, there is little doubt that their range and numbers have drastically declined since the arrival of Europeans on the island over 4000 years ago. Deforestation is likely to have had a big impact on both species – before the arrival of humans it is thought that Hispaniola had a forest cover of around 98%, whereas the Dominican Republic now has around 28% and Haiti has less than 4% forest cover. Other potential major threats to both species also include the introduction of non-native carnivores and competitors, such as dogs, cats, mongoose and rats, and also direct persecution by local people.
So the jury is very much out on what the status and current threats are for both species, and this knowledge gap lies at the core of the work of the Last Survivors project. In some areas of Hispaniola, both species appear to be surviving in small forest fragments set in agricultural landscapes. This brings them into conflict with people in both direct and indirect ways. The extensive protected area network in the Dominican Republic provides some safeguard against habitat destruction, but agricultural activity and deforestation continues to occur even within the boundaries of some national parks. These protected areas are also unlikely to protect native mammals from the effects of introduced species. Luckily there are several national conservation organisations, including our main project partner the Sociedad Ornitologíca de la Hispaniola, who are working very hard to conserve these species and their habitat.
By the early 1900s the solenodon was thought to be extinct, and was rediscovered in 1908 by Alpheus Hyatt Verrill. There is little doubt that solenodon populations have undergone a dramatic decline since first human arrival on Hispaniola, but no information is currently available to provide a measure of the scale of this decline.
There is some evidence to suggest that even before Europeans arrived in Hispaniola in 1492, the local indigenous Amerindians hunted the species as a source of protein. The main threat today may be deforestation. Solenodons may also be adversely affected by invasive mammal species, and in particular there appears to be evidence of frequent killing of solenodons by both domestic and feral dogs. A recent interview with a park guard revealed that a dog had killed five solenodons in one night. If this sort of predation is at all typical, then this would obviously be having an immense impact on the species.
The effect of alien species may not only be a direct one. For example, local people put out poisoned bait to control the mongoose that prey on their chickens. Since solenodons seem to be quite opportunistic in their food choice they may well be feeding and dying from eating the poison bait – an indirect effect that could well explain any potential correlation between mongoose in an area and reduced solenodon numbers. We need to investigate all these perceived threats before coming to any solid conclusions.
Hispaniolan hutias are partly arboreal mammals that feed on leaves, fruit, shoots and bark, and so may be more dependent than solenodons on the presence of forested environments. Deforestation is therefore likely to be the most direct threat to their ongoing survival. In some areas small populations which survive in forest fragments set within agricultural landscapes may be coming into conflict with people, as villagers in both the Dominican Republic and Haiti often complain of crop damage caused by hutias. As forest habitat becomes increasingly fragmented across Hispaniola, not only is hutia habitat being destroyed but human-animal conflict may also escalate.
The hutia used to be hunted opportunistically as a source of food in the Dominican Republic, and this still occurs in southern Haiti. As human populations continue to increase and resources become more limited for low-income communities, could this become a more significant future threat to the Hispaniolan hutia?
A large number of hutia species have disappeared from the islands of the Caribbean over the past few hundred or thousand years, following human arrival in the region. The other two species of hutia in Hispaniola belonging to the genus Plagiodontia may have disappeared after the arrival of Europeans around 500 years ago. The extinction of these species may have been driven by direct human predation, escalating deforestation, or the introduction of rats, dogs, and other non-native mammals; or possibly these extinctions were driven by a combination of all of these factors.
All of the hutia family is endemic to the Caribbean, and all hutia species are restricted to single islands or neighbouring island groups. Of the 13 surviving hutia species, the IUCN (International Union for the Conservation of Nature) classifies four species as Critically Endangered, four as Endangered (including the Hispaniolan hutia), three as Vulnerable, one as Near Threatened, and only one as Least Concern. Some of the species listed as Critically Endangered, such as the Cuban dwarf hutia (Mesocapromys nanus), have not been seen for decades. Worryingly we know very little about most hutias, and we still don’t know exactly what has caused the extinction of so many species and what factors are threatening the ones that are left