Assessing the Ecological Risk of a Municipal Solid Waste Landfill to Surrounding Wildlife: a Case Study in Florida

Abstract

To assess the ecological risk of siting a new municipal solid waste landfill near a National Wildlife Refuge in Florida, we carried out a retrospective assessment at a large waterbird colony located near an existing active landfill. Monitoring data collected over twenty years, including flight-line counts both at dawn and midday, shows the mixed-species, communal roost was active continuously from 1987 through 2007. The largest number of birds counted in any single flight-line count was 14,750 birds recorded in July 2007. The numerically dominant species recorded during flight-line counts were, in approximate order of abundance: White Ibis, (Eudocimus albus), Cattle Egret (Bubulcus ibis), Little Blue Heron (Egretta caerules), Great Egret (Ardea alba), and Tricolor Heron (E. tricolor). Breeding bird censuses revealed this site served also as a nesting colony each year since 1987; annual total nest numbers peaked in 1987 at 5,127 nests. Taxa richness increased over the monitoring period with new species nesting or roosting in the colony; in particular, the endangered Wood Stork (Mycteria americana) began nesting at this site in 1995 and eventually became one of the numerically important species. Nest success at the landfill colony was similar to or higher than success probabilities reported at other colonies in south Florida. Fidelity to this colony site was likely related to the area's environmental predictability in terms of: 1) food supply and, 2) the low, temporally constant level of predation. In general, resident waterbird populations at the colony were sustainable over the monitoring period, i.e., maintained abundance, survived and reproduced at rates comparable to other colonies. Therefore, although there was evidence of organism-level impacts, there was no evidence that landfill-related stresses propagated up and had population- or community-level consequences.

Keywords:

• solid waste landfill
• heron
• egret
• ibis
• stork
• colony dynamics

Acknowledgments

The authors wish to thank all those who participated in the twenty-year monitoring program: Richard Statom, Ken Berg, Fred Bothe, Donna Deis, Greg Isphording, Amanda Krupa, Rusty Kestle, Chris Koch, Karen Larson, Daryl Moore, Chris Peretta, Jim Tanner, Albert Vazquez, Jeanette Madey, Monica Tojek, Tracy Caisse, Michael Voich, Todd Sandt, David Broten, Mark McLean, J.C. Griffin, Mark A. Davis, Josephine Rudd, and Mike Tyson. The authors greatly appreciate also the constructive comments from three anonymous reviewers which helped us to improve the revised version of the paper.