Fig. 1 in Butterfly extirpations, discoveries and rediscoveries in Singapore over 28 years

Fig. 1. Vegetation cover change and the number of butterfly species in Singapore from 1819–2017. The percentages of vegetation cover change from 1819–1990 were extracted with permission from Corlett (1992) and extended till 2017 using Yee et al. (2011) and NParks (2017). Agricultural land included tree crops such as rubber; managed vegetation included parks, gardens, and turf. The vegetation cover area under each habitat type was calculated by the area between any of the two vegetation cover lines marked in grey. Species were defined as extirpated in 1956 if they were not recorded for 30 years (shown in grey rectangle) by Corbet & Pendlebury (1956). Forty-nine and 144 butterfly species were not recorded since 1926 and 1990 respectively as shown by the blue line. Nine species could be additionally ('potentially') extirpated since 1990 (as indicated by the blue shaded area). An increase in the number of extirpated & extant species was due to new species discoveries (new country records) and rediscoveries since 1956. Fleming (1975, 1991) added new country records till 1975, but they did not report any extirpations. Therefore, the number of extant species in 1975 was unknown (as indicated by the green dotted line).