Short-term anuran community dynamics in the Missouri River floodplain following an historic flood

Abstract

Extreme ecological disturbances such as floods, wildfires, and droughts are difficult to study because they are rare and unpredictable. We had the opportunity to study the effect of an historic flood on an anuran community in the Missouri River floodplain. We used occupancy estimation to estimate the proportion of wetlands occupied by calling adult male anurans. Three species - the plains leopard frog (Lithobates blairi), Woodhouse's toad (Anaxyrus woodhousii), and Blanchard's cricket frog (Acris blanchardi) - had only minor changes in occupancy rate two years after the flood. Colonization rates for these species were positively associated with wetlands that were shallower near the shore and they did not appear to be affected by reduced vegetation. Three other species or species complexes - the northern leopard frog (Lithobates pipiens), the gray treefrog complex (Hyla versicolor and Hyla chrysocelis), and the boreal chorus frog (Pseudacris mandata) - had greatly reduced occupancy rates two years after the flood. Colonization rates for these species were relatively low, while they had high extinction rates. Colonization rates for these species were not associated with any habitat characteristic we measured. Future flood events will likely continue to make northern leopard frogs, gray treefrogs, and boreal chorus frogs a less important part of the ecological community. While some species may fare well under extreme climate events, such as this flood, that are forecast under climate change scenarios, many species will struggle.