On each side of the boardwalk at Buffalo Creek, areas 0–5 m from the boardwalk
(near) and areas 20–25 m (away) from the boardwalk were divided into two 435 m
patches, 0–4 m and 4–8 m from the creek. The abundance of crabs in each patch was
measured by direct visual counts (Warren, 1987). A motionless observer counted the
2 crabs that emerged from burrows within a 0.25 m quadrat during the 10 minutes after the appearance of the first crab on the surface. If no crabs appeared in 15 minutes, the
quadrat was recorded as a zero, because H. cordiformis usually emerge 5–10 minutes
after being disturbed (Warren, 1987). Three replicate quadrats were counted in each
patch.