Does a long‐term shift in Wood Stork diet foreshadow adaptability to human‐induced rapid environmental change?

Abstract

To preserve biodiversity, identifying at‐risk populations and developing conservation plans to mitigate the effects of human‐induced rapid environmental change (HIREC) are essential. Changes in diet, especially for food‐limited species, can aid in detecting populations being impacted by HIREC, and characterizing the quality, abundance, and temporal and spatial consistency of newly consumed food items may provide insight concerning the likelihood of a species persisting in a changing environment. We used Wood Storks (Mycteria americana) nesting in the Florida Everglades as a model system to study the possible effects of HIREC on a food‐limited population. We compared the diets of Wood Storks in 2013 and 2014 with those reported during the 1970s before major anthropogenic activities affected the Everglades system and prey availability. Wood Storks in our study consumed more large‐bodied sunfish species (Lepomis spp.), fewer native marsh fishes, and more non‐native fish species than during the 1970s. Large sunfish and non‐native fish are relatively rare in the drying pools of Everglades marshes where storks traditionally forage, suggesting that Wood Storks may be using novel foraging habitats such as created wetlands (i.e., canals and stormwater ponds). Although created wetlands have long hydroperiods conducive to maintaining large‐bodied fishes and could provide alternative foraging habitat when prey availability is reduced in natural marshes, additional studies are needed to determine the extent to which these wetlands are used by Wood Storks and, importantly, the quality of prey items potentially available to foraging Wood Storks in created wetlands.

Commuters: a waterbird provides a new view of how species may utilize cities and wildlands

“…Non-native fish, which are prey for storks, have been expanding their ranges in south Florida since the 1950s, but they notably increased after changes to water management regimes in the 1990s (Kline et al 2014). Storks nesting in both urban and marsh colony types now consume non-native fishes, which is a change from the stork's diet prior to the 1980s (Klassen & Gawlik 2018). Diet is a key mechanism of demographic change for food-limited species, so changes in diet such as the ones observed by Klassen and Gawlik (2018) and Evans and Gawlik (2020) could have significant impacts on productivity and survival.…”

“…Storks nesting in both urban and marsh colony types now consume non-native fishes, which is a change from the stork's diet prior to the 1980s (Klassen & Gawlik 2018). Diet is a key mechanism of demographic change for food-limited species, so changes in diet such as the ones observed by Klassen and Gawlik (2018) and Evans and Gawlik (2020) could have significant impacts on productivity and survival. The presence of non-native fish may affect storks positively or negatively, possibly in a complex manner.…”