Abstract.

Invasive species pose serious ecological and economic threats to native biological systems. The temporal dynamics of invasions are often difficult to characterize but can provide key insights into patterns of establishment and spread of introduced species. Herein, we reconstructed the timeline of historic occurrence for all three invasive anurans in Florida, Greenhouse Frogs (Eleutherodactylus planirostris), Cane Toads (Rhinella marina), and Cuban Treefrogs (Osteopilus septentrionalis). We analyzed publicly available data sets using geostatistical spatial interpolation to assess the expansion of these species within Florida since their introduction. Our analysis indicates that all three species underwent a patchy dispersal involving multiple translocation events. Greenhouse Frogs have occupied Florida since 1930 but started increasing their occupancy in the 1970s. In contrast, both Cane Toads and Cuban Treefrogs were introduced to the mainland by the 1960s and were restricted to small geographic regions of Florida until about 1990 when both species increased their rate of spread. Currently, the expansion rates of Greenhouse Frogs and Cane Toads show signs of decreasing while the invasive range of Cuban Treefrogs continues to grow at an exponential rate. Our results reveal that after a relatively long integration phase, there was a sharp increase in the area occupied by all three species. The timing and duration of the exponential phase, however, differed among species. By comparing invasion histories across species, we discuss potential drivers that may have influenced these anuran invasions. This study shows that historic records, despite their limitations, can help reconstruct the range expansion process of invasive species.