The Effects of Canals on Alligators in the Everglades

Poster presented December 2000, at the Greater Everglades Ecosystem Restoration Conference

Matthew D. Chopp¹, Kenneth G. Rice², Frank J. Mazzotti³, H. Franklin Percival¹

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Abstract

Introduction

Objectives

Alligator hole maintenance Canal influence on alligator populations extends approximately 1 kilometer into the marsh (Mazzotti et al. 1999).
Alligator holes in Water Conservation Area 3A [larger image]	Measuring an alligator hole in Shark Slough, Everglades National Park [larger image]
	Distribution of observed and expected values of number of alligator holes in 1 km-wide transects [larger image]

Alligator home range and movement Alligators living in canals use larger home ranges and move more than alligators in natural marsh habitats (See Home Range and Movement of Alligators in the Everglades, Morea et. al.).
Mean annual and seasonal homeranges for radio-tagged gators in WCA 3A North and ENP. [larger image]	Mean annual and seasonal minimum daily movement for radio-tagged gators in WCA 3A North and ENP. [larger image]

Alligator production Alligator production and hatchling survival may be less in canal habitats (M. Chopp, Unpub. Data).

Marking alligator eggs in the nest [larger image] Alligator Nest Inundation Status [larger image] Alligator Nest Success [larger image] Year 2000 Preliminary Data taken at A.R.M. Loxahatchee N.W.R.

Alligator population density and size structure Adult alligator densities are higher in canal habitats than those in the marsh interior (Mazzotti et. al., 1999).
Alligator Population Survey Routes [larger image]	Average density of Alligators in Canals, Marshes and Rivers of the Everglades [larger image]

Alligator habitat preference Habitat preference for canals among adults occurs, meaning alligators that live in canals stay there (See Home Range and Movement of Alligators in the Everglades, Morea et. al.).
Miami Canal, WCA 3A North [larger image]	Habitat availability and use for canal alligators located in WCA 3A North and ENP from 1 July 1997 to 21 September 1998. [larger image]

Alligator physical condition Adult body condition may be better in canals than in the marsh.
Unhealthy/poor condition Everglades alligators in a legal Florida hunt [larger image] Photo courtesy Florida Fish and Wildlife Conservation Commission	Healthy alligator in good physical condition [larger image] Photo courtesy Adam Britton
Snout-Vent Length (SVL) vs. Mass Body Length vs. Mass for alligators in the Everglades compared to other populations in northcentral Florida and South Carolina. [larger image]

Alligator thermoregulation Canal alligators appear to have a metabolic thermal advantage in some seasons (See Thermoregulation of the American Alligator in the Everglades, Percival et. al.).
Technological advances have allowed miniaturization of temperature data logging devices so that continuous data collection is now possible through implantation. Photo by M. Caudill [larger image]	The typical pattern of body temperature of an alligator from WCA 3A North. [larger image]

Affiliations

1. U. S. Geological Survey, BRD Florida Cooperative Fish and Wildlife Research Unit 117 Newins-Ziegler Hall, University of Florida Gainesville, FL 32611
2. U.S. Geological Survey, BRD, FCSC Everglades National Park Field Station 40001 State Road 9336 Homestead, FL 33034
3. Department of Wildlife Ecology and Conservation Institute of Food and Agricultural Sciences University of Florida 3243 College Ave Davie, FL 33314

Acknowledgements

Literature Cited