In July 2021, we reported on concerning trends in the abundance and condition of the Barbados leaf-toed gecko following ashfall from the eruption of La Soufriere volcano. The population at Paragon was reassessed in December 2021 and though there has been some piecemeal improvement, there is still cause for concern. Body condition of geckos has improved slowly though is still not back to pre-ash levels.
What does “body condition” mean? Put simply, body condition is a measure of how much energy reserves an animal has. Basically, how heavy a gecko is compared to its length much like BMI in humans. A gecko that is heavier than another of the same length is likely to be getting more food. Improvement in body condition of geckos is an expected result of increasing insect availability. Tracking these trends in Barbados leaf-toed geckos is not only relevant to conservation of the species on the island but is also of intellectual interest as there is little literature on the impacts of ash on reptiles. Impacts seen here can inform expectations of the effects on reptiles experiencing ashfall elsewhere.
One finding reported in literature is that reproduction is postponed soon after ashfall, with a high percentage of females bearing young in the following year. This seems to have been observed in leaf-toed geckos also. Only 14% of females captured in May-June of 2021, soon after ashfall, bore eggs which increased to 27% in November-December. Most bore one egg though one female was found bearing two. By contrast, 50% of female geckos bore eggs in February. Of those females with eggs, over half were found with two eggs. So in a short 2 months the number of females seen with eggs doubled, and the number of females bearing two eggs increased sevenfold. An increase in sightings of females with eggs accompanied by an increase in sightings of new-born geckos suggests that the reproductive success of the gecko has not been severely impacted and the next generation of geckos is on its way to maturity.
Encouragingly, gecko body condition and abundance at another assessed site appears to have returned to normal. Due to the fragmented nature of their population, there are concerns regarding abundance and health of the smaller populations of geckos. As a result, range surveys are currently underway to ascertain whether geckos are still present in their previously documented range. Some small populations were estimated in 2019 to have as few as 20 individual geckos living in them. If measurable declines in population were observed at Paragon, a large area, one would be justified in worrying about the persistence of small populations.