A census of breeding bird populations was taken in a 40- hectare wetland near Biwabik, Minnesota, prior to the use of this wetland for phosphorus removal from treated wastewater. The wetland was comprised of four distinct habitat types: shrub swamp, black ash (Fraxinus nigra) forest, open coniferous forest, and closed coniferous forest. We used a line transect (about 4 km in length) to document species composition, relative species abundance, and habitat associations of the bird community. A total of816 individuals (mean= 204) and 45 species (mean = 34) were observed during four censuses in June and July, 1985. Two distinct bird communities were present in this wetland: those associated with ombrotrophic habitats (shrub swamp and ash forest) and those present in mincrotrophic habitats (open and closed coniferous forest). The Nashville warbler ( Vermivora ruficapilla) was the most common species in the wetland and also the only species that occurred in both minerotrophic and ombrotrophic habitats. The pre-impact data collected will allow assessment of the relative impact of adding sewage effluent to this wetland and the subsequent effect on bird species and populations

Hanowski, Joann M.

Niemi, Gerald J.

English

University of Minnesota, Morris (UMM): Digital Well

Journal of the Minnesota Academy of Science Volume 52 Number 3 Article 3 1987 Breeding Bird Populations in a Proposed Wetland Treatment Area of Northern Minnesota Joann M. Hanowski University of Minnesota, Duluth Gerald J. Niemi University of Minnesota, Duluth Follow this and additional works at: https://digitalcommons.morris.umn.edu/jmas  Part of the Ornithology Commons Recommended Citation Hanowski, J. M., & Niemi, G. J. (1987). Breeding Bird Populations in a Proposed Wetland Treatment Area of Northern Minnesota. Journal of the Minnesota Academy of Science, Vol. 52 No.3, 7-10. Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol52/iss3/3 This Article is brought to you for free and open access by the Journals at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Journal of the Minnesota Academy of Science by an authorized editor of University of Minnesota Morris Digital Well. For more information, please contact skulann@morris.umn.edu. Breeding Bird Populations in a Proposed Wetland Treatment Area of Northern Minnesota JOANN M. HANOWSKI and GERALD]. NIEMI* ABSTRACT- A census of breeding bird populations was taken in a 40-hectare wetland near Biwabik, Minnesota, prior to the use of this wetland for phosphorus removal from treated wastewater. The wetland was comprised of four distinct habitat types: shrub swamp, black ash (Fraxinus nigra) forest, open coniferous forest, and closed coniferous forest. We used a line transect (about 4 km in length) to document species composition, relative species abundance, and habitat associations of the bird community. A total of816 individuals (mean= 204) and 45 species (mean = 34) were observed during four censuses in June and July, 1985. Two distinct bird communities were present in this wetland: those associated with minerotrophic habitats (shrub swamp and ash forest) and those present in ombrotrophic habitats (open and closed coniferous forest). The Nashville warbler ( Vermivora ruficapilla) was the most common species in the wetland and also the only species that occurred in both minerotrophic and ombrotrophic habitats. The pre-impact data collected will allow assessment of the relative impact of adding sewage effluent to this wetland and the subsequent effect on bird species and populations. Introduction Plans are underway to use a 40-hectare wetland near Biwabik, Minnesota, to remove phosphorus from treated wastewater prior to its entry into Embarass Lake ( 1 ). Wetlands are particularly sensitive to changes in water chemistry and these changes will probably affect the vegetation present in the wetland. Changes in vegetation may then affect species composition of the wetland fauna. Because birds are good indicators of environmental changes (e.g., vegetation changes), they are often used to assess the effects of an environmental perturbation in an area (2, 3). Our objective was to survey breeding bird populations in this wetland before its use as a sewage treatment area. Specifically, we documented bird species composition, relative species abundance, and habitat associations of bird species in the wetland. Materials and Methods The proposed wetland treatment site is located about one kilometer south of Biwabik, Minnesota between State High-way 135 and St. Louis County Highway 4 (Figure 1). The wetland is comprised of four distinct habitat types: shrub swamp, ash forest, open coniferous forest, and closed conif. erous forest (Figure 1). The shrub portion of the wetland was 4 hectares in area and the most common species were speckled alder (Alnus rugosa) and willow (Salixspp.). The shrub wetland gradually changed to an ash swamp to the south. This habitat type was 6 hectares in area and the under· story vegetation contained alder, willow, cattail (Typha latifo-lia), wild calla (Calla palustris), and wild iris (Iris versicolor). *Natural Resources Research Institute, University of Minnesota, Duluth Volume 53, Number 3, 1986/87 The main portion of the wetland was 28 hectares and was a closed spruce and tamarack (Picea mariana and Larix laric-ina) forest. A 2-hectare open spruce and tamarack forest was present in the middle of the wetland. Common understory vegetation in the open areas was leatherleaf ( Chamaedaphne calyculata), bog laurel (Kalmia polifolia), small cranberry ( Oxycoccus microcarpa), and cotton grass (Eriophorum spp.) Labrador tea (Ledum groenlandicum), three-leaved false Solomon's seal (Smilicina trifolia), and sedges ( Carex spp.) were common in the closed canopy areas. The distinc-tion between the open and closed forest was due to differ-ences in density and height of trees. The shrub swamp and ash forest were classified as minero-trophic habitats. In minerotrophic habitats, the water table is above the peat surface and these areas receive nutrients from adjacent and underlying mineral soil. The coniferous forest habitats were ombrotrophic habitats. In ombrotrophic habi· tats, the water table is below the peat surface and water is drained from these areas. In these habitats, the primary source of minerals is rainfall. Consequently, nutrient levels are much higher in minerotrophic as compared with ombrotrophic hab-itats within a wetland complex ( 4). The nutrient level also affects the type of plant species that occur. Broad-leaved deciduous species are more common in minerotrophic habi-tats and narrow-leaved evergreen species are prevalent in ombrotrophic habitats. Four censuses of the wetland were taken during the breed-ing season Oune to early July) using line transects ( 5 ). Census data were collected during early morning hours (0445-0930 central daylight savings time) and on mornings with winds less than 10 km/hour and with no precipitation. The observer walked a pre-determined route of 4 km through the wetland on a route planned to traverse all habitat types. The number of birds of each species was recorded as well as the approximate distance of each kind from the transect. The habitat affinity of 7 Biwabik City limits .: ~-·· . ......... . . . . Ash Forest Shrub Swamp Open Coniferous Forest Closed Coniferous Forest--+.'-. . -: ............ '\ . . . • • • • • . . ... . . . . . . . . . • • . • • Treatment Area Boundary 1 km Figure 1. Location of study area near Biwabik, Minnesota each bird species was also noted. The size (ha) of each habitat type was obtained from aerial photographs. Results and Discussion Bird density and habitat affinity A total of 816 individuals were counted during the four censuses for a mean of 204 individuals/census. A low of 152 individuals was observed on June 13 and a high of 225 indi-viduals on July 1 (Table 1). The total number of species observed was 45 with a high of38 species on]uly 3 and a low of 30 species on June 28 (Table 1 ). Twice as many individuals were observed in minerotrophic as compared with ombro-trophic habitats (8.0 and 4.1 individuals/hectare respec-tively). This pattern was similar to what has been found in other northern Minnesota wetlands and is, presumably, due to the trophic status and consequent productivity of the habitats (6). 8 The most abundant species in the wetland was the Nash-ville warbler [ Vermivora ruficapilla ( 40.8 individuals/cen-sus)]. It was also the only species that occurred in both minerotrophic (ash forest) and ombrotrophic (closed conif-erous forest) habitats. Most northern Minnesota wetland spe-cies occur within either minerotrophic or ombrotrophic habi-tats ( 6). In previous studies, only one other species, the Savannah sparrow (Passerculus sandwichensis) was asso-ciated with both trophic peatland types (7, 8). However, these two species occur over a wide range of habitats during the breeding season; therefore, it is not unusual that they occupy both trophic types. For example, the Nashville warbler breeds along edges of habitats, in mixed deciduous-coniferous uplands, and in shrub wetlands (7, 9, 10). Other common species (those with a mean of> 5 indivi-duals/census) in the wetland were: yellow-bellied flycatcher (Empidonax flaviventris), veery ( Catharus fuscescens), her-journal of the Minnesota Academy of Science Table 1. Total and mean number of individuals observed for each row ( Melospiza georgiana), white-throated sparrow ( Zonotri-species and each date and their habitat affinity in the proposed chia albicollis), and dark-eyed junco (Junco hyemalis). These Biwabik wetland treatment site, 1985. Habitat codes are represented species were also the most common in similar wetland habi-by letters; ash swamp (A), closed conifer forest (C), open conifer tats in northern Minnesota (7, 8). forest (0), and shrub wetland (S). Date Species richness June ~ As expected, a direct relationship exists between the Species Habitat 13 28 1 3 Mean number of species present and the size of the habitat. The Mallard A 2 2 1.0 most species (23) were associated with the most common habitat type (closed coniferous forest) and fewest species ( 3) Sharp-shinned hawk c 1 2 0.8 were found in the habitat (open coniferous forest) that occu-Black-billed cuckoo s 3 0.8 pied the smallest area (Table 1 ). More species were associated Black-backed woodpecker c 2 0.8 Northern flicker A 0.5 with the ombrotrophic (26 species) as compared with the Olive-sided flycatcher c 1 0.3 minerotrophic habitats (22 species), but this was probably Yellow-bellied flycatcher c 12 9 7 5 8.3 because the area of ombrotrophic habitat types sampled was Alder flycatcher s 5 3 5 6 4.8 larger. Higher species richness observed in larger sized habi-Least flycatcher A 2 1 0.8 tats is due to a species/area effect. That is, the number of Eastern kingbird 0 2 1 0.8 species observed in a habitat is proportional to the size of area Gray jay c 3 3 2 1 2.3 sampled. To control for this effect, we used the rarefaction Blue jay c 1 4 3 2.0 procedure (11). This allowed us to simulate a census of American crow c 3 3 7 4 4.3 same-sized habitats by calculating the number of species Black-capped chickadee c 2 3 1.3 expected if the same unit of area had been used. Rarefaction Boreal chickadee c 2 2 1.0 Red-breasted nuthatch c 1 0.3 results for the Biwabik wetland indicated that we would Sedge wren s 2 1 8 2.8 expect to count seven species in the ash forest, the shrub Golden-crowned kinglet c 6 2 1 1 2.5 swamp, and the closed coniferous forest and three species in Ruby-crowned kinglet c 2 1 1 1 1.3 the open coniferous forest if we censused the same amount of Veery A,S 4 9 5 7 6.3 each habitat (2 ha). These results are similar to what we have Hermit thrush c 7 5 9 10 7.8 found in other northern Minnesota wetlands (7, 8). Gray catbird s 1 2 0.8 Solitary vireo c 2 2 1.0 Bird community responses to added wastewater. Red-eyed vi reo A 8 8 6 7 7.3 Previous investigators who have studied bird communities Nashville warbler C,S 22 58 49 34 40.8 in wastewater treatment areas have reported mixed results. Yellow warbler s 2 4 6 3.0 Kadlec (12) reported that no major shifts in avian species Chestnut-sided warbler A 1 2 1 1 1.3 Yellow-rumped warbler c 8 9 11 6 8.5 abundance or composition occurred at a wetland treatment Blackburnian warbler c 1 0.3 area near Houghton Lake, Michigan. However, a significant Palm warbler C,O 10 11 11 7 9.8 increase in bird diversity was reported for a treatment area in a Black-and-white warbler A 5 1 1 2 2.3 Florida cypress dome (13). Fuller and Glue (14) suggested American redstart A 2 4 4 2.5 that sewage treatment facilities, especially lagoons, served as Connecticut warbler c 8 14 8 7 9.3 important feeding sites for passerine species and that this type Common yellowthroat A,S 6 12 16 17 12.8 oftreatment site (surface irrigation) would support the most Rose-breasted grosbeak A 2 5 5 4 4.0 diverse bird communities. However, the physiological effect Chipping sparrow c 6 4 6 1 4.3 on individuals that use these areas as feeding sites during Clay-colored sparrow s 1 3 10 3.5 breeding or migration have not been assessed and the long-Song sparrow s 1 4 9 4 4.5 term effects are still unknown (13). Lincoln's sparrow 0 2 7 7 6 5.5 The addition of wastewater to this northern Minnesota Swamp sparrow A,S 7 9 9 16 10.3 White-throated sparrow c 6 23 12 13 13.5 wetland will probably increase the amount of nutrients and Dark-eyed junco c 2 7 5 6 5.0 the water depth and subsequently increase the area of minero-Red-winged blackbird s 2 2 1.0 trophic habitat types. Therefore, densities of species asso-Brown-headed cowbird C,A 3 5 3 3.0 ciated with the closed and open coniferous forests would Purple finch A 1 0.3 probably decrease. Also, we would expect a decrease in spe-Total (Individuals) 152 222 225 217 203.8 cies found in ombrotrophic habitats. These changes would be Total (Species) 34 30 36 38 45 a result of either the addition or loss of a particular habitat type Number of species in ash or an increase or reduction in size of existing habitat types. swamp habitat 14 In this study we have gathered information on several bird Number of species in closed species, including densities and habitat affinities, in the pro-spruce habitat 23 posed wetland treatment area. This information will allow us Number of species in open to examine the relative changes in species composition and spruce habitat 3 Number of species in shrub changes in their habitat affinity following the addition of habitat 11 treated wastewater beginning in the fall of 1986. However, because of the high annual variation in bird populations, data collected for only one breeding season may be inadequate to assess changes in the density of all species after wastewater is mit thrush ( Catharus guttatus), red-eyed vireo (Vireo oliva-added to the wetland, especially the less common species. ceus), yellow-rumped warbler (Dendroica coronata), palm The "best" pre-impact studies are those that are done over a warbler (D. palmaru m), Connecticut warbler ( Oporornis agi-number of years, but such studies are exceptions rather than lis), common yellowthroat ( Geothlypis trichas), swamp spar-the rule ( 15, 16). Although data presented here are valuable as Volume 53, Number 3, 1986/87 9 baseline information, we emphasize that a longer pre-impact data base is needed to improve our assessment of the effects of disturbances on ecological systems. Furthermore, using wetland systems like bogs for phosphorus retention needs critical evaluation since it is questionable whether these wetlands are useful for this purpose (17). References 1. Minnesota Pollution Control Agency. 1982. Authorization to discharge and construct wastewater treatment facilities under the National Pollutant Discharge Elimination Sys-tem and State Disposal Permit Program. Permit No: MN0053279. 2. Jarvinen, 0., and Vaisanen, R. 1979. Bird population changes as bioindicators. In: The use of ecological varia-bles in environmental monitoring. The National Swedish Environment Protection Board, Report PM 1151. 3. Niemi, GJ., Hanowski, J.M., Kouki, ]., and Rajasarkka, A. 1984. Intercontinental comparisons of habitat structure as related to bird distribution in peatlands of eastern Finland and northern Minnesota, USA. In: Fuchsman, W., and Spigarelli, S.A. (eds.), Proceedings of the International Symposium on Peat Utilization, pp. 59-73. Bemidji State University, Bemidji, Minnesota. 4. Heinselman, M.L. 1971. Landscape evolution, peatland types, and the environment in the Lake Agassiz Peatland Natural Areas, Minnesota. Ecological Monographs 40:235-261. 5. Jarvinen, 0., and Vaisanen, R. 1975. Estimating the relative densities of breeding birds by the line transect method. Oikos 26:316-322. 6. Niemi, GJ., and Hanowski,J.M. (In press) Birds of Minne-sota peatlands. In: Wright, H. Jr., Coffin, B. and Aaseng, N. (eds.), The Patterned Peatlands of Northern Minnesota. Minneapolis: University of Minnesota Press. 10 7. Niemi, GJ., andHanowski,J.M. 1984. Effects of a transmis-sion line on bird populations in the Red Lake Peatland northern Minnesota. Auk 101:487-498. 8. Hanowski,J.M., and Niemi, GJ. 1985. Habitat characteris-tics for bird species of special concern and their impor-tance in habitat reclamation. Report to Minnesota DNR Non-game and Minerals Divisions. 9. Bent, A.C. 1963. Life Histories of North American Wood Warblers. New York: Dover Publishing Inc. 10. Green, ].C., and Niemi, GJ. 1978. Birds of the Superior National Forest. Special Publication of the Superior National Forest. pp. 1-82. 11. James, F.C., and Rathbun, N.O. 1981. Rarefaction, relative abundance and diversity of avian communities. Auk 98: 785-800. 12. Kadlec, J.A. 1979. Nitrogen and phosphorus dynamics in inland freshwater wetlands. In: Bookhout, T.A. (ed.), Waterfowl and Wetlands- An Integrated Review. Pro-ceedings of a Symposium, 39th Midwest Fish and Wildlife Conference, Madison, WI, pp. 17-41. LaCrosse, WI: LaCrosse Printing Company. 13. United States EPA. 1983. The effects of wastewater treat-ment facilities on wetlands in the Midwest. EPA Tech Rpt. 905/3-83-002. 14. Fuller, R.J., and Glue, D.E. 1980. Sewage works as bird habitats in Britain. Biol Conserv. 17:165-181. 15. Beanlands, G.E., and Duinker, P.N. 1984. An ecological framework for environmental impact assessment. ]. Environ. Manage. 18:266-277. 16. Rosenberg, D.M., and Resch, V.H. 1981. Recent trends in environmental impact assessments. Can. ]. Fish. Aquat. Sci. 38: 591-624. 17. Richardson, C.]. 1985. Mechanisms controlling phospho-rus retention capacity in freshwater wetlands. Science 228: 1424-1427. Journal of the Minnesota Academy of Science 

Breeding Bird Populations in a Proposed Wetland Treatment Area of Northern Minnesota

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Breeding Bird Populations in a Proposed Wetland Treatment Area of Northern Minnesota

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