Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
(a) Population structure of R. aldabrae collections (open bars, juvenile; grey bars, subadult; black bars, adult). (b) Correlation between rainfall and number of R. aldabrae fresh shells and live snails collected on Aldabra atoll (1966–1997; data from subsequent years are not used because no recent R. aldabrae shells were located). (c) Frequency of low-rainfall years (black bars, under 1023 mm; grey bars, over 1023 mm). No data for 1951–1957, 1960–1967 and 1984–1993.
