United StatesDepartment ofAgricultureForest ServicePacific NorthwestRe - PDF document

United StatesDepartment ofAgricultureForest ServicePacific NorthwestResearch StationResearch PaperPNW-RP-539December 2001Avian and Amphibian Use ofFenced and Unfenced StockPonds in Northeastern OregonForestsEvelyn L. Bull, Jerry W. Deal, and Janet E. Hohmann is a research wildlife biologist, Forestry and Range Sciences Labora-Jerry W. Deal is a regional wildlife is a wildlife contractor, Wallowa, OR 97885. PNW-RP-539. Portland, OR: U.S. Department of Agriculture, Forest Service, PacificPseudacris regillafound between fenced and unfenced ponds. Fencing at least a portion of stock pondsKeywords: Amphibians, birds, livestock grazing, northeastern Oregon, stock ponds.Development of water sources in the form of stock ponds has benefited wildlife, as wellvegetation surrounding the ponds. Amphibian larvae did not detectably benefit from thefenced ponds. These findings may suggest that livestock grazing did not have a nega- Thispagehasbeenleftblankintentionally.Documentcontinuesonnextpage. 1994). Grazing greatly impacts some vertebrate populations, primarily through indirecteffects on the habitat structure and prey availability, although there also can be directwater quality. Fencing is done both to protect the resources and to provide habitat forwildlife, but it has not been determined if fencing actually benefits wildlife in these for-dance of amphibians at fenced and unfenced ponds on forest lands.based on accessibility and for being more than 0.5 km from other ponds that were se-until late September.Density and effective area for each species detected more than once were calculatedtrix approach found in Verner (1984) (table 1). We also created taxonomic groups,expressed as density of birds per 1000 ha. For each set of density estimates and de-was chosen over a paired-sample t-test because the probability plots of the differences GuildNesting locationFeeding locationGRGRGround, includes cliffsGround, air aboveGRSHGroundShrubsGRWAGroundWater: in, on, or nearSHGRShrubsGroundSHSHShrubsShrubsTRGRTree boles, large branchesGroundTRSHTree boles, large branchesShrubsTRTRTree boles, large branchesTree boles, large branchesCAGRTree canopyGroundCACATree canopyTree SNGRSnagsGround and air aboveSNTRSnagsTree boles, large branches TaxonDescriptionANATGeese and ducksBLBRBlackbirds and oriolesCHARShore and marsh birdsCORVCorvidsFLYCFlycatchersFNCHFinchesGAMEGrouse and dovesKINGBelted kingfisherOWLSOwlsPCNHChickadees, creepers, nuthatchesSTAREuropean starlingSWFTSwifts and hummingbirdsSWLOSwallowsTHRSThrushes (including kinglets andVREOVireosWOODWoodpeckers and sapsuckersWRBLWarblersWRENHouse wren and the effective area of the variable circular plot. The plot radius used to estimate15 June 1993. This time interval was selected because larvae of all three speciesRelative abundance of larvae was determined by using eight sweeps with a dip net intervals around the periphery of the pond. Thetotal number of larvae caught per pond was recorded by species. We compared theThe fenced plots had significantly higher densities for bird species (Z = -3.05, P )cause of the differences in detection distances but rather a result of more birds occur-The densities in fenced plots was more than double those in unfenced plots in theguilds of birds that nested on the ground (GRGR, GRSH, GRWA), fed on the groundthrushes, wrens, blackbirds, finches, swallows, shore and marsh birds, and starlings = 60.8 larvae captured in sweeps per pond containing thisspecies; SD = 93.05) of the unfenced and 88 percent ( = 47.2 larvae per pond; Table 3—The guild, taxon, and density (number per 1000 ha) of each bird speciesSpeciesGuildTaxonFencedUnfenced)TRGRHAWK21912)SHGRTHRS2,2361,572Black-headed grosbeak ()CACASPAR1919)SNTRWOOD1717)CAGRBLBR89426Molothrus ater)SHGRBLBR1,9511,536)TRTRPCNH1,150419)CAGRFNCH2,1931,350)SHGRSPAR5,2645,581)CACACORV633)GRGRSWLO4480)GRGRCORV3743)GRWACHAR111)GRGRSPAR4,3339,099)TRGRSTAR486134)CAGRFNCH45226)CACATHRS2,1591,082)TRGRCORV24547)CAGROWLS026)GRWAANAT0236)TRTRWOOD5191)CACAFLYC797944)GRGRTHRS8351)TRGRWREN1,536257)SHSHWRBL089)GRWAANAT822199Sialia currucoides)SNGRTHRS23585)TRCHPCNH1,456962)SNGRWOOD126150)CACAFLYC028)GRSHWRBL2090)SNTRWOOD1514 Table 3—The guild, taxon, and density (number per 1000 ha) of each bird species Relative densitySpeciesGuildTaxonFencedUnfenced)CACAFNCH1,776290)SHGRBLBR1,5979)CAGRHAWK725)TRTRPCNH1,3391,247)TRTRWOOD13138)CACATHRS210144)GRSHGAME63)CACAVREO16522)CAGRCORV85115)SHSHTHRS1708)CACAWRBL452163)SNGRSWLO5780Unidentified bird — —110134Unidentified bluebird —THRS50205Unidentified finch —FNCH1,150151Unidentified flycatcher —FLYC20550Unidentified sapsucker —WOOD3726Unidentified sparrow —SPAR7726Unidentified warbler —WRBL544456Unidentified woodpecker —WOOD1413)GRGRSPAR120)CACAVREO077)SNTRTHRS2,618240 spp.)CACAFLYC038)GRGRBLBR27116)CACABLBR695451)CACAFLYC265226)TRTRWOOD4128)SHSHWRBL1,0671,884 6 Figure 1—Density (number per 1000 ha) of bird guilds using fenced and unfenced ponds in northeasternOregon, 1993. northeastern Oregon, 1993. = 27.9 larvae per pond; SD = 35.84) of the unfenced = 20.7 larvae per pond; SD = 18.94) of the fenced ponds. Larvae = 11.5 larvae per pond; = 32.8 larvae per pond; SD = 61.1) of the(figs. 1 and 2). The greater abundance of many of these birds is explained by the moreabundant vegetative ground cover in the areas protected from livestock grazing. Thedenser ground cover and vegetation would provide more material for nesting, moreabundance of potential hosts in the Northern Rockies. The higher numbers we ob-served at fenced ponds may have been a function of the higher diversity of birds (andAlthough we found no references to studies comparing avifauna using fenced and un-rangelands. Grazing in stock ponds reduced pair numbers, nesting densities, and nestsuccess of waterfowl in North Dakota (Kirsch 1969). Grazing on small pond shorelinesin Texas resulted in a severe reduction of foliar cover and vegetation height; fencing atMany studies comparing avian use of grazed and ungrazed riparian habitats haveriparian areas in Oregon, and bird counts were 5 to 13 times higher in ungrazedareas than in grazed areas. Avian species richness and relative abundance werePredation on real and on artificial bird nests was higher in grazed versus ungrazed There has been considerable speculation on the influence of livestock on amphibiansColumbia spotted frogs were associated with sites with significantly less grazing pres-sure than sites without frogs, although there were no differences in a subsequent yearnot differ between fenced and unfenced ponds, although we did not determine recruit-hatched. Trampling of recently metamorphosed individuals may occur at unfencedFenced stock ponds provided a greater diversity and density of birds in forested habi-tats than unfenced ponds; this was likely because of the difference in vegetation sur-reproduction in the amphibian species considered, although survival and recruitmentwere not determined. These findings suggest that fencing at least a portion of the pe-When you know:Multiply by:To find:0.039InchesMeters (m)3.28FeetKilometers0.625MilesHectares (ha)2.47Acres Livestock effects on reproduction of the ColumbiaEhrlich, P.R.; Dobkin, D.S.; Wheye, D. 1988. The birder’s handbook: a field guide to Ecological costs of livestock grazing in western North America.Horusp, A.C.; James, C.; Porter, G. 1993. Vertebrates of dry rainforest of south and Amphibian and reptile species of special concern Impacts of a late season grazingProceedings of a symposium on wildlife-livestock relationships. Moscow, ID:Kirsh, L.M. 1969. Waterfowl production in relation to grazing. Journal of Wildlife Breeding bird populations in a grazed and ungrazed Breeding bird populations in a grazed and ungrazedStatus and habitatassociations of the spotted frog Rana pretiosa in southwestern Idaho. Tech. Bull.96-1. Boise, ID: Idaho Bureau of Land Management. 11 p.Nussbaum, R.A.; Brodie, E.D., Jr.; Storm, R.M. 1983. Amphibians and reptiles of thePatil, S.A.; Kovner, J.L.; Burnham, K.P. 1982. Optimum nonparametric estimation of A variable circular-plot method The cowbird’s invasion of the Far West, causes and con- Livestock grazing effects inwestern North American. In: Martin, T.E.; Finch, D.M., eds. Ecology and manage-western North American. In: Martin, T.E.; Finch, D.M., eds. Ecology and manage-Quantitativesampling of amphibian larvae. In: Heyers, W.R.; Donnelly, M.A.; McDiarmid, R.W.[and others], eds. Measuring and monitoring biological diversity: standard methods Statistical methods. 7 ed. Ames, IA: Iowa Effects of cattle grazing on passerine birds nesting in riparian Wildlife habitats in managed forests of the Blue Mountains of The guild concept applied to management of bird populations.Whyte, R.J.; Cain, B.W. 1981. Wildlife habitat on grazed and ungrazed small pond Thispagehasbeenleftblankintentionally.Documentcontinuesonnextpage. of the U.S. Department of Agriculture is dedicated to the principleapply to all programs.) Persons with disabilities who require alternative means forprovider and employer.(503) 808-2592(503) 808-2138(503) 808-2130P.O. Box 3890 P.O. Box 3890