Datafile - In situ adaptation and ecological release facilitate the occupied niche expansion of an invasive Madagascan day gecko in Florida

Aim To investigate whether the frequently advocated climate-matching
species distribution modelling approach could predict the
well-characterized colonization of Florida by the Madagascar giant day
gecko Phelsuma grandis. Location Madagascar and Florida, USA. Methods To
determine the climatic conditions associated with the native range of P.
grandis, we used native-range presence-only records and Bioclim climatic
data to build a Maxent species distribution model and projected the
climatic thresholds of the native range onto Florida. We then built an
analogous model using Florida presence-only data and projected it onto
Madagascar. We constructed a third model using native-range presences for
both P. grandis and the closely related parapatric species P. kochi.
Results Despite performing well within the native range, our Madagascar
Bioclim model failed to identify suitable climatic habitat currently
occupied by P. grandis in Florida. The model constructed using Florida
presences also failed to reflect the distribution in Madagascar by
over-predicting distribution, especially in western areas occupied by P.
kochi. The model built using the combined P. kochi/P. grandis dataset
modestly improved the prediction of the range of P. grandis in Florida,
thereby implying competitive exclusion of P. grandis by P. kochi from
habitat within the former’s fundamental niche. These findings thus suggest
ecological release of P. grandis in Florida. However, because ecological
release cannot fully explain the divergent occupied niches of P. grandis
in Madagascar versus Florida, our findings also demonstrate some degree of
in situ adaptation in Florida. Main conclusions Our models suggest that
the discrepancy between the predicted and observed range of P. grandis in
Florida is attributable to either in situ adaptation by P. grandis within
Florida, or a combination of such in situ adaptation and competition with
P. kochi in Madagascar. Our study demonstrates that climate-matching
species distribution models can severely underpredict the establishment
risk posed by non-native herpetofauna.