Waterfowl use of managed and unmanaged beaver ponds in south-central Ontario / T. Shane Gabor, Henry R. Murkin, and Joel W. Ingram.

Includes bibliographical references (pages 55-57).

We studied waterfowl habi tat lise and resource ava ilability on beaver (Caslor
canadensis) ponds in south-central Ontario . We studied 6 types of natural beaver ponds
(aquatic bed, emergent, forested, scrub-shrub, ull vegetaled, seasonally flooded) and I
managed beaver pond (dewatered for > 1 year to rejuvenate vegetation cOI1Untmi lies and
then fe-flooded). Waterfowl lise was determined from helicopter surveys for breeding
pairs and elevated platfonTIs for broods. Invertebrate and minnow abundance and
biomass were determined using sweep net samples. Mallard (Anas p/alyrhynchos) pair
dens ities were higher (P = 0.001) on emergent (0. 16 ± 0.02 SE) and scmb-slmlb (0.20 ±
0.03) wetlands than on seasonally nooded (0.08 ± 0.02) ponds. Wood duck (Aix .lpUlISO)
pair densities were higher (P = 0.000 I) on forested (0.20 ± 0.04), emergent (0. 14 ± 0.03)
and unvegetated (0.23 ± 0.06) wet lands than on seasonally nooded ponds (0.01 ± O.OJ).
Hooded merganser (Lophodytes CIIClll/otllS) pair densities were hi gher (P = 0.0001) on
forested (0. 10 ± 0.02) and unvegetated (0.07 ± 0.0 I) ponds than on scmb-shrub (0.0 I ±
0.01) and seasonally nooded (0) wetlands. Differences in brood densities were not
detected between wetland classes for mallardlblack duck (P = 0.08), wood ducks (P =
0. 17) and all species combined (P = 0.44). Hooded merganser brood dens ities were
higher (P = 0.02) on forested (0.66 ± 0.22) and unvegetated (0.59 ± 0.23) wetl ands than
on emergent (0) wetlands. In June, total invel1ebrate biomass was higher (P = 0.008) in
emergent (0 .72 ± 0. 32), forested (0.78 ± 0.30), scmb-shmb (0.75 ± 0.24), and managed
wetlands (0.70 ± 0. 17) than in unvegetated ponds (0.08 ± 0.05). In July, total inve'1ebrate
biomass was higher (P = 0.009) in emergent (1 .23 ± 0.38) and managed (0.99 ± 0.22)
wetlands than in unvegetated ponds (0.07 ± 0.03). Managed wet lands had similar
productivity to natural vegetated wetlands and therefore intens ive water level management
to increase waterfowl producti vity has limited potential. \Vaterfowl use in the region is
primarily affected by wetland avail abili ty. Beaver abundance and distribution detennille
wetland availability and therefore, programs, partnerships, and pol icy initiatives that
consider bo th forestry and beaver management wi ll positive ly impact waterfowl ill
Canadil 's fores ted regions.