TABLE OF CONTENTS TABLE OF CONTENTS... 1 EXECUTIVE SUMMARY... 2 INTRODUCTION... 4 METHODS... 5 Route and Station Selection and Characteristics...

Transcription

1 The Marsh Monitoring Program Report: Monitoring Great Lakes Wetlands and Their Amphibian and Bird Inhabitants Steven T.A. Timmermans and G. Eoin Craigie Bird Studies Canada P.O. Box 16 Port Rowan, Ontario NE 1M November

2 1 TABLE OF CONTENTS TABLE OF CONTENTS... 1 EXECUTIVE SUMMARY... INTRODUCTION... 4 METHODS... 5 Route and Station Selection and Characteristics... 5 Amphibian Survey Protocol... 6 Bird Survey Protocol... 6 Habitat Assessments... 7 Population Trend Analysis... 7 RESULTS... 8 Routes... 8 Habitat... 9 Amphibians... 1 Birds DISCUSSION AND CONCLUSIONS... 1 RESEARCH NEEDS ACKNOWLEDGEMENTS LITERATURE CITED TABLES... FIGURES APPENDICES... 43

3 EXECUTIVE SUMMARY Wetland loss in some areas of the Great Lakes basin has exceeded 8% since European settlement (Snell 1987, Dahl 199). One of the most ubiquitous and important wetland types are marshes (Weller 1981). Marshes occur at both isolated inland and exposed lakeshore contexts throughout much of the Great Lakes basin. Marshes support the highest diversity and biomass of floral and faunal species than any other wetland type (Weller 1978, Weller 1981), and are perhaps the most important natural mechanism for maintaining water quality to support life, including human life. Many birds and amphibians frequent and rely heavily on marshes to support their annual life cycle (Weller 1999). With continual degradation and loss of marsh habitat, there has long been a recognized need to monitor populations of avian and amphibian species that rely on these sensitive wetland environments. In 1995, a bi-national Great Lakes basinwide effort was launched in a multi-partner effort to establish the Marsh Monitoring Program, a program whose primary goal is to monitor populations of marsh birds and calling amphibians across wetlands in this globally unique and water-rich region. Since 1995, through a partnership between Bird Studies Canada, the United States Environmental Protection Agency, Environment Canada, Great Lakes United, the Great Lakes Protection Fund, and hundreds of citizen scientists, the Marsh Monitoring Program has succeeded in capturing important and meaningful population and wetland habitat information from hundreds of wetlands throughout the Great Lakes basin. MMP surveyors follow a standardized protocol and are guided by detailed written and aural training materials. Surveys are conducted at semi-circle shaped stations positioned along routes. A nocturnal survey is conducted for calling frogs and toads three times during spring and early summer. An evening survey is done for birds twice during the height of breeding season, and is augmented by use of taped broadcasts to illicit response calls from several secretive species. MMP participants also provide assessments of wetland habitat at survey stations. Data summaries in this report provide an overview of information contributed by MMP surveyors from 1995 through 1. Most summaries provide focus on the Great Lakes basin but data are also presented for individual lake basins. In total, 1,73 volunteers submitted data from 654 routes during the period 1995 through 1. Most routes (558 routes, 85% of total) were within the Great Lakes basin but a small proportion (96, 15%) occurred outside the basin. Lake Erie, Ontario and Huron basins contained the most routes (183, 163 and 11, respectively) with fewer routes in Lakes Michigan and Superior basins (75 and 7, respectively). On average, most MMP surveys were done in large permanent wetlands. Approximately 55% of MMP station areas were covered with non-woody, emergent vegetation, and about 6% of these areas were open water. Cattail and grasses/sedges were the dominant emergent plants at the majority of the stations but their respective dominance varied among lake basins. MMP surveyors recorded 13 species of calling amphibians within the Great Lakes basin during the 1995 through 1 period. Spring Peeper was the most frequently detected

4 3 species followed by Green Frog. Grey Treefrog, American Toad and Northern Leopard Frog were moderately common while Chorus Frog, Bullfrog and Wood Frog were less common. These eight species varied in their distribution among lake basins. Because the range of most species extends the breadth of the Great Lakes basin, patterns are not likely due to range limitations per se; differences in habitats, regional population densities, timing of survey visits or other factors are more likely explanations. Spring Peeper was encountered frequently in all Great Lake basins but least often in the Lake Ontario basin. Northern Leopard Frog was detected most frequently in the Lakes Ontario and Erie basins. Although the MMP has yet to gain long-term population-monitoring data, some apparent significant decreasing temporal trends were suggested for populations of American Toad, Bullfrog, Chorus Frog and Green Frog. The extent to which additional years of data might be expected to provide good resolution on amphibian occupancy trends was assessed. The expected annual trend (i.e., percent change in population index based on station occupancy) was calculated assuming either 1, or 3 routes were monitored over three, five and 1 years. With 1 routes measured for 1 years, the estimated annual change in occupancy from 5% was about 1% or less for all of the 8 amphibians commonly recorded on MMP routes. As expected, resolution improved with and 3 routes for 1 years. Expected trend resolution was best for American Toad and Green Frog, and was lower for species that were less common (Bullfrog, Chorus Frog and Wood Frog) or that fluctuated widely in station occupancy (Spring Peeper). These results suggest that additional years of data are likely to improve the ability of MMP data to provide trend estimates for several amphibian species, including species of conservation and management concern such as Northern Leopard Frog and Bullfrog. Fifty-three species of birds that use marshes for feeding, nesting or both were recorded by MMP observers at Great Lakes routes. Among birds that typically feed in the air above marshes, Tree and Barn Swallow were most common. Red-winged Blackbird was the most commonly recorded marsh nesting species, followed by Swamp Sparrow, Common Yellowthroat and Yellow Warbler. Several species closely associated with marshes were also observed in substantial numbers of stations. Many of these species (e.g., Virginia Rail, Black Tern and Sora) are not well surveyed by other monitoring programs. Individual bird species varied considerably in their distribution among lake basins, probably due to factors including differences in species geographic range and variation in wetland habitat characteristics among basins. In general, station occupancy by aerial foraging and marsh nesting birds tended to be highest in the Lake Ontario basin, intermediate in the Lakes Erie and Huron basins, and lowest in Lake Superior basin. Although additional years of data are required to estimate population trends with strong precision, results of preliminary analyses are presented for those species for which sufficient data were available. Statistically significant declining trends were detected for American Coot, Black Tern, Blue-winged Teal, moorhen/coot, Pied-billed Grebe, Redwinged Blackbird, Sora, Tree Swallow and Virginia Rail. Statistically significant increases were detected for only Common Yellowthroat and Mallard. For many species, changes in relative abundance tended to differ among lake basins. Expected detectable annual trend (i.e., percent change in population index based on counts) was calculated for aerial foraging and marsh nesting birds assuming that either 1, or 3 routes were

5 4 monitored for three, five or 1 years. With at least 1 routes surveyed for 1 years, good trend resolution is expected for 14 of 8 species commonly recorded at MMP routes. Included in this group are several species associated with deeper water wetland habitats (e.g., Pied-billed Grebe, Common Moorhen) and many others associated with dense wetland vegetation (e.g., Virginia Rail, Marsh Wren, Common Yellowthroat, Swamp Sparrow, Red-winged Blackbird). On average, about 15 routes were surveyed annually between 1995 and 1, suggesting that current level of effort is appropriate for more than half of the 8 species commonly recorded by MMP surveyors. This report summarizes the first seven years of MMP implementation across the Great Lakes basin and is an update of the five-year MMP assessment (Weeber and Vallianatos ). It provides an overview of data collected from 1995 through 1 and shows how MMP is playing a role in many of today s (and tomorrow s) conservation issues and actions at different scales. In addition, this report is a statement of appreciation to those agencies and foundations that have supported the MMP throughout the years. Last but not least, this report is intended to convey to the hundreds of Great Lakes citizens who have volunteered with the program that their contributions are both highly valued and extremely important. INTRODUCTION The Marsh Monitoring Program (MMP) has been monitoring trends in marsh bird and calling amphibian occurrence indices for seven years. As such, this report summarizes results of data collected throughout the Great Lakes basin from 1995 through 1 and is a follow-up to the MMP five-year assessment (Weeber and Vallianatos ). The report describes trends in relative abundance and occurrence of marsh birds and calling amphibians (frogs and toads). Many of the marsh bird and amphibian species (see Appendix 1 and ) that are monitored by MMP volunteer participants are recognized as important faunal indicators of wetland health and condition. Efforts to monitor and evaluate relative status of marsh birds and amphibians across the Great Lakes basin are essential to understanding how well marshes within and across the basin are functioning to maintain ecological integrity. For instance, marsh birds as a group are believed to have experienced population declines due to historical habitat loss and degradation (Gibbs et al. 199, Conway 1995, Melvin and Gibbs 1996). Further, concern for declining amphibian populations is recognized internationally (Heyer et al. 1994, Stebbins and Cohen 1995). Marshes that support a diversity of wetland dependent species are considered to be healthy and functioning at an optimal state. Numerous marsh bird and amphibian species are believed to be sensitive to habitat disturbances, and many scientists and conservationists consider their populations to be at risk due to continued habitat loss. Currently, limited information is available concerning habitat associations for marsh bird and amphibian species across the Great Lakes basin. MMP volunteer participants help provide a detailed assessment of this important function of wetland habitat. When combined with information about trends in species occurrence and abundance, data on vegetation and other wetland characteristics

6 5 help identify those wetland habitats at most risk of losing their ability to support a diversity of marsh birds and amphibians. Data provided by MMP volunteer participants are being used to assist efforts to conserve and rehabilitate wetlands, provide critical information for effective wetland management and propose conservation practices to benefit wetland-dependent wildlife and people. Local citizen groups use MMP data to better understand and maintain wetlands in their locales. MMP data contributes to management plans at the regional scale (e.g., Great Lakes Areas of Concern), individual lake basin scale (e.g., Lakewide Management Plans) and to assess wetland health at the Great Lakes basin-wide scale (e.g., State of the Lakes Ecosystem Conference). Moreover, MMP data serve to increase awareness of marsh bird, amphibian and wetland habitat conservation issues though volunteer participation and communication to the public, scientists and regulators. In this report, both basin-wide and within-basin summaries are provided for marsh birds and amphibians for the first seven years of MMP implementation across the Great Lakes basin. General trends are provided for several marsh dependent bird and calling amphibian species occurring with some regularity throughout the Great Lakes basin. Significant increases or declines in annual occurrence indices have occurred for several marsh bird and amphibian species. These data are assessed across the entire Great Lakes basin, and less extensively at the individual lake basin level. Results are calculated for Lakes Michigan, Huron and as one water body due to their hydrological connection. Population indices of waterfowl may be inaccurate due to limitations of the MMP protocol to adequately detect those species and because waterfowl often nest in upland habitats. Further, we recognize that there is a possibility that volunteer-selected marshes are not entirely representative of wetlands throughout the Great Lakes basin because they are not selected randomly. This limitation will be addressed as a research need later in this report. Because the MMP is still intensifying its geographical coverage, and because sample sizes sometimes prevent derivation of reliable trend data, summaries for certain species in some basins are not provided due to lack of route coverage and/or statistical power. In addition, data are still insufficient to calculate population indices or trends in the Lake Superior basin, thus data from this basin did not contribute to Great Lakes basin-wide analysis of marsh bird and amphibian trends. METHODS MMP data are gathered by volunteers in Canada and the United States. MMP volunteers contribute their valuable time to monitor abundance and occurrence of marsh birds and calling amphibians throughout marshes of the Great Lakes basin. Key elements of MMP sampling methodology are reported herein, and additional detailed information concerning MMP protocol and methodology can be found in Anonymous (1). Route and Station Selection and Characteristics Upon registering with the MMP, volunteers receive training kits that include detailed protocol instructions, field and summary data forms, instructional cassette tapes with examples of songs and calls of common marsh birds and amphibians, and a broadcast tape used to elicit calls from secretive wetland bird species. MMP volunteers

7 6 establish survey routes in marshes at least 1-ha in size. Each route consists of one to eight monitoring stations depending on such factors as available time and marsh habitat. Each marsh bird survey station must be separated by at least 5 m (75 yd) to minimize duplicate counts of individuals. Due to difficulties in judging distances and locations of calling amphibians, stations surveyed for amphibians must be separated by at least 5 m (55 yd). An MMP station is defined as a 1 m (11 yd) radius semicircle with marsh habitat covering greater than 5% of the semicircle area. Marsh habitat is defined as habitat regularly or periodically wet or flooded to a depth of up to two metres (six feet) where cattail, bulrush, burreed and other non-woody vegetation is predominant. Counts are conducted from a focal point at each station the surveyor stands at the midpoint of the m ( yd) semi-circle base and faces the arc of the station perimeter. Each focal point is permanently marked with a stake and metal tag to facilitate relocation within and between years. Amphibian Survey Protocol Amphibians surveyed by MMP volunteer participants are calling frogs and toads that typically depend on marsh habitat during spring and summer breeding periods. MMP routes are surveyed for calling amphibians on three nights each year, between the beginning of April to the end of July, with at least 15 days occurring between visits. Because peak amphibian calling periods are strongly associated with temperature and precipitation rather than date, visits are scheduled to occur on three separate evenings according to minimum night air temperatures of 5 C (41 F), 1 C, (5 F), and 17 C (63 F), respectively. Amphibian surveys begin one-half hour after sunset and end before midnight. Visits are done during evenings with little wind, preferably in moist conditions with one of the above corresponding temperatures. During three-minute survey visits, observers assign a Call Level Code to each species detected; for two of these levels, estimated numbers of individuals are also recorded. Call Level Code 1 is assigned if calls do not overlap and calling individuals can be discretely counted. Call Level Code is assigned if calls of individuals sometimes overlap, but numbers of individuals can still reasonably be detected. Call Level Code 3 is assigned if so many individuals of a species are calling that overlap among calls seems continuous; a count estimate is impossible for Call Level Code 3 and is not required by the protocol. Beginning in 1999, MMP participants were asked to use their best judgement to distinguish whether each species detected was calling from inside the station boundary only, from outside the station boundary only, or from both inside and outside. Combined with habitat information provided for each station by MMP surveyors, this modification will improve information concerning amphibian habitat associations. Bird Survey Protocol Survey visits for birds are conducted twice each year, with at least 1 days between visits, from May to July 5. Visits must begin after 18: h and are to be done under appropriate survey conditions (i.e., warm, dry weather and little wind). A fiveminute broadcast tape is played at each station during the first half of each 1-minute survey visit. The broadcast tape helps elicit calls from several normally secretive bird

8 7 species and contains calls of Virginia Rail, Sora, Least Bittern, Common Moorhen, American Coot and Pied-billed Grebe. During the count period, observers record all birds heard and/or observed within the survey station area and record all observations onto a field map and data form. Aerial foragers are also counted and are defined as those species foraging within the station area to a height of 1 m (11 yd). Bird species flying through or detected outside the station are tallied separately. Habitat Assessments MMP surveyors conduct an annual assessment of habitat characteristics for each of their MMP stations. Volunteers are encouraged to conduct habitat surveys during midto late June, when plants can be readily identified. Observers provide information about coverage of five general habitat types: herbaceous emergent plants; open water; exposed mud, rock or sand; trees; and shrubs. Percent coverage of the four most dominant types of emergent plants is also recorded, providing a more detailed assessment of this important component of wetland habitat. Observers record coverage of floating plants and estimate wetland size and permanency, and adjacent land use. Observers also sketch a map illustrating general habitat characteristics of each station. Population Trend Analyses Occurrence indices were derived for each species (bird and amphibian) in each survey year. For marsh birds, abundance indices were based on counts of individuals inside the MMP station boundary and were defined relative to 1 values. General models (PROC GENMOD; SAS Institute Inc.) were developed to generate annual indices for each marsh bird species. Indices were scaled to correct for over-dispersion prior to transformation for regression analyses. Analyses to test overall effect of year as a class variable or as a continuous variable were done using likelihood ratio tests (PROC GENMOD; SAS Institute Inc.) to compare deviance of these models with no year variable. For each year, 95% confidence limits around each annual index were calculated. Presented in each figure and table herein are estimated annual percent changes (trends) in abundance of each marsh bird species and the associated upper and lower extremes of the 95% confidence limits for each species trend. Because actual counts of marsh birds provide a Poisson distribution of observations, Poisson regression was used to evaluate year-to-year variance of annual indices and overall direction of trends across years. For calling amphibians, occurrence indices were based on annual proportion of survey stations with each species present and were defined relative to 1 values. As with birds, indices were scaled to correct for over dispersion prior to transformation for regression analyses. Analyses to test overall effect of year as a class variable or as a continuous variable were done using likelihood ratio tests (PROC GENMOD; SAS Institute Inc.) to compare deviance of these models to models with no year variable. For each year, 95% confidence limits around each annual index were calculated and both estimated annual percent change (trends) in occurrence of each amphibian species, and the associated upper and lower extremes of the 95% confidence limits of each species trend are presented herein. Because indices were derived based on presence or absence of a given species at a given station, this produced a binomial distribution of observations, thus logistic (or binary) regression was used to evaluate year-to-year

9 8 variance of annual indices and overall direction of trends in amphibian occurrence across years. Statistically testing for year-to-year variance of occurrence indices provides knowledge about whether occurrence indices for a given species were similar or different among years, whereas statistically testing for overall magnitude and direction of trends across years evaluates whether temporal trends differed from a slope of zero (i.e., no change). It is important to emphasize that the most meaningful interpretation of results is done by assessing both year-to-year variance in annual indices as well as overall magnitude and direction of trends. For example, a species may have exhibited high yearto-year variance in occurrence indices, yet the overall trend may not have differed from a slope of zero. Similarly, for example, a significant positive or negative trend over time may have occurred for a given species, but may have been driven by a single yearspecific index value having differed considerably from those of all other years combined. In the latter example, significant year-to-year variance in indices may not have occurred, and such a scenario is less meaningful than if both year-to-year variance and overall direction of a trend had occurred (i.e., each or most years having contributed to overall increase or decline in trends). RESULTS This report focuses on results of MMP surveys conducted within the Great Lakes basin (Figure 1) and emphasizes results for marsh birds and calling amphibian species believed to be most clearly associated with marshes and other wetland and aquatic habitats. Analyses that considered every route surveyed in a given year as a single observation and did not differentiate between routes surveyed for a single and multiple years, were summaries of MMP data in terms of route-years. Similarly, the term stationyear referred to the basic sample unit for those analyses that considered stations without regard to the number of years each station was surveyed. Unless otherwise mentioned, most analyses in this report were based on route-year and station-year approaches. Routes In total, 173 volunteers submitted data from 654 routes from 1995 through 1. Most routes (558 routes, 85% of total) were within the Great Lakes basin. The Lake Erie basin contained the most routes (183, 7% of total), followed by Lakes Ontario (163, 4%) and Huron (11, 16%) basins; fewer routes occurred in Lakes Michigan (75, 11%) and Superior (7, 4%) basins (Table 1). Within the Great Lakes basin, survey data from 549 amphibian routes and 499 bird routes were submitted during the seven-year period. Similar numbers of routes were surveyed for amphibians only, birds only and for both groups (Table 1). Mean number of routes surveyed per year was 35 and peaked in 1997 (Table 1). Overall, a large percentage of amphibian routes (39%) were surveyed for one year only, fewer for two or three years (17% and 1%, respectively) and fewer yet for additional years (Table ). Similarly, a large percentage of bird routes (4%) were surveyed for 1 year only (Table ). Seventeen percent of bird routes were monitored for two years, 11% for three years and smaller percentages for longer durations. A higher proportion of bird routes were monitored for the full 7-year period (9%), than for

10 9 amphibian routes (3%). Routes within the Great Lakes basin had an average of 3.9 stations. Mean number of stations was similar for bird and amphibian routes and varied little across years or among lake basins (Figure ). Most (75% of station-years) MMP surveys were done in permanent wetlands with the rest done in semi-permanent (17.5%) and seasonal (7.5%) wetlands (Figure 3). There was an increase in proportion of stations in semi-permanent wetlands after 1996 (Figure 3A). Lake Superior had the greatest proportion of stations in permanent wetlands while a smaller percentage of Lake Michigan s stations occurred in this wetland class (Figure 3B). Overall, approximately 3% of stations occurred in "huge" wetlands, a similar proportion was in "large" and "tiny" wetlands (% and 19%, respectively), and the remainder were split between "medium" and "small" wetlands (15% and 14%, respectively). Distribution of wetland sizes fluctuated among years (Figure 4A). Among lake basins, only stations in Lake Michigan were approximately evenly distributed among wetland size classes. The huge wetland size class predominated for Lakes Ontario, Erie and Huron while both huge and large wetland size classes predominated in Lake Superior (Figure 4B). Habitat Due to revision of MMP habitat assessment protocols for the 1997 survey season, habitat characteristics are summarized in this report for 1997 onward only. Stations within the Great Lakes basin had mean station area coverage of 55.4% non-woody, emergent vegetation and 6.% of the area in open water. Exposed substrate (e.g., mud, rock), trees and shrubs represented.%, 7.4% and 7.7% coverage, respectively. These patterns were observed in all lake basins, although stations in Lake Superior had lower mean coverage of exposed substrate than stations in other basins (Figure 5). Plant species contributing more than 1% to overall coverage of non-woody, emergent vegetation were considered dominant; all others were classified as subdominant. Cattail was the most dominant emergent plant in the Great Lakes basin (37.8%), but grasses/sedges were also dominant at 5% of stations. A variety of other plant species dominated 16.3% of stations and mixes of species, none dominant, occurred at.9% of stations. In Lakes Ontario, Erie and Michigan basin stations, cattail encompassed a large portion (58%, 4% and 44%, respectively) of the emergent vegetation (Figure 6). Cattail and grasses/sedges were equally dominant (36% and 31%, respectively) in Lake Huron stations. Cattail encompassed only a small proportion of the emergent vegetation (6%) in Lake Superior; most of these stations were dominated by either grasses/sedges or by a mix of subdominant species. Cattail and grasses/sedges were present in most station-years (approximately 8% and 6%, respectively) (Figure 7A). All other emergent plants were detected in fewer than 5% of stations. Where they did occur, cattail and grasses/sedges tended to dominate, grasses often comprising at least % of the emergent plant community and cattail often comprising at least 6% (Figure 7B). Where species other than cattail and grasses/sedges occurred, these tended to contribute relatively little (most often 19% or less) to overall emergent plant coverage for most stations. However, where they did occur, rushes, Smartweed, Water Willow and Common Reed each contributed more than % cover to the emergent community of a substantial percentage (at least 4%) of stations.

11 Amphibians MMP surveyors recorded a total of 13 species of calling amphibians from 1995 through 1. Spring Peeper was the most frequently detected species (69% stationyears) (Table 3) and was recorded with the highest average calling code (.5). Green Frog was detected frequently (54% station-years), but its average calling code was fairly low (1.3). Grey Treefrog, American Toad and Northern Leopard Frog were also common and were recorded in greater than 3% of station-years. Grey Treefrog was recorded with the second highest average calling code (1.8). Chorus Frog, Bullfrog and Wood Frog were detected in greater than 18% of station-years. Five species were detected infrequently by MMP surveyors and were recorded in less than 3% of station-years (Table 3). The eight amphibian species commonly detected (present in at least 3% of stationyears) by MMP surveyors varied to some extent in their distribution among lake basins (Table 3). American Toad was detected with similar frequencies among all lake basins. Green Frog occurred with similar frequencies in Lakes Ontario, Erie, Huron and Superior basins, whereas Bullfrog was recorded frequently in the Lake Erie basin only. Northern Leopard Frog was detected most frequently in the Lakes Ontario and Erie basins. Spring Peeper was detected most frequently in Lakes Erie, Huron, Michigan and Superior basins and occurred less frequently in Lake Ontario. Basin-wide trends in station occupancy were assessed for the eight most commonly detected amphibian species. For each species, a trend was assessed first on a route-by-route basis in terms of annual proportion of stations with each species present. These route level trends were then combined for an overall assessment of trend for each species. Declining trends for American Toad, Chorus Frog and Green Frog could be resolved with sufficient statistical confidence (i.e., confidence limits do not encompass zero). However, for some species, changes in species trends were strongest only in specific lake basins. For instance, a significant decline in occurrence of both American Toad and Green Frog (Figure 9 A,D) appeared to be largely due to trends in Lake Huron and Lake Michigan-Huron basins (P <.5); since occurrence in other lake basins did not show significant declines. Whereas Bullfrog occurrence increased significantly in Lake Huron and Lake Michigan-Huron basins, significant declines occurred in Lakes Erie and Ontario basin MMP routes (P <.5) (Figure 9B). Chorus Frog and Spring Peeper station occurrence (Figure 9 C,F) declined significantly in Lakes Michigan, Huron and Michigan-Huron basins (P <.5). Whereas Leopard Frog occurrence declined significantly in the Lake Erie basin, occurrence increased significantly in the Lake Ontario basin (P <.5). The extent to which additional years of data may be expected to provide adequate resolution on amphibian occupancy trends was assessed based on MMP data collected from 1995 through 1. The annual trend (i.e., percent change in relative occurrence index based on station occupancy) from 5% occupancy that could be detected was estimated assuming that either 1, or 3 routes were monitored over three, five or ten years (Table 4). With 1 routes measured for 1 years, the estimated annual change from 5% occupancy that could be detected was about 1% per year or less for all of the eight amphibians commonly recorded on MMP routes. Resolution improved with and 3 routes, respectively. Expected resolution on trends was best for American Toad 1

12 11 and Green Frog, followed by Bullfrog, Chorus Frog, Grey Treefrog and Northern Leopard Frog. Resolution was lower for species that were less common (i.e., Wood Frog) or that exhibited large fluctuations in station occupancy (i.e., Spring Peeper). Birds MMP observers recorded a total of 7 bird species from 1995 through 1, with 191 of these species counted inside MMP station boundaries. Of the 53 species commonly recorded (present in at least.5% station-years) by MMP observers on Great Lakes routes, 45 are classified as typically nesting in marshes (marsh nesters) and eight typically use air space above marshes for feeding (aerial foragers; may also nest in wetlands). Although data are presented for American Coot and Common Moorhen, their calls can often be difficult to distinguish. Records for when MMP observers failed to differentiate these species are also summarized in this report as a combined species (MOOT). Tree and Barn Swallows were the most commonly occurring aerial foragers, recorded in 53.3% and.3% of station-years, respectively (Table 5). The other six aerial foraging species occurred much less frequently (<7% of station years). Redwinged Blackbird was the most commonly recorded marsh nesting species, occurring in 8.1% of station-years. Swamp Sparrow was observed in 48.% of station-years, and four other songbirds (Common Yellowthroat, Yellow Warbler, Song Sparrow and Marsh Wren) were almost as common. Several other marsh nesting species were observed in approximately 1 to 5% of station years. Of special note among these species are several water birds not well surveyed by other monitoring programs: Virginia Rail, moorhen/coot (undifferentiated), Black Tern, Common Moorhen, Pied-billed Grebe and Sora. Canada Goose and Red-winged Blackbird occurred in the highest numbers at 5.6 and 5.1 individuals per station, respectively. Common Grackle, Mallard and moorhen/coot each averaged greater than 3.5 individuals per station. In contrast, few stations where bitterns or Willow Flycatchers were observed contained more than one individual. When compared across the Great Lakes basin, aerial foragers and marsh nesting birds occurred at the greatest proportion of station-years in the Lake Ontario basin ( = 14.9) and at the lowest proportion of stations in the Lake Superior basin ( = 11.3). Mean values of the Lake Erie ( = 14.), Huron ( = 13.) and Lake Michigan ( = 13.7) basins were intermediate. More marsh nesting and aerial foraging birds were detected at stations in the four lower Great Lakes than on routes in the Lake Superior basin (Table 5). In contrast, several of the more commonly recorded bird species (Tree Swallow, Yellow Warbler, Common Yellowthroat, Song Sparrow, Swamp Sparrow, Red-winged Blackbird) were detected on a high portion (at least 3%) of Lake Superior stations. Some related species often differed in the frequency of their abundance among lake basins. American Bittern was detected most frequently in the Lake Huron basin while Least Bittern occurred in similar proportions of station-years across the Ontario, Huron and Erie basins. Virginia Rail and Sora also differed in their abundance, with the former detected most often in Lakes Ontario and Huron basins and the latter detected in similar proportions of stations across all basins except Lake Erie. Almost all records of Alder Flycatcher were detected in the Lake Superior basin, while Willow Flycatcher was detected in similar proportions across Lakes Ontario, Erie and Michigan basins with few

13 1 records in the Lakes Huron and Superior basins. Pied-billed Grebes were detected across all lake basins, but relatively few were recorded in the Lake Superior basin. Black Tern was found most often in the Lake Huron basin and was not recorded in the Lake Superior basin. The extent to which additional years of monitoring would be expected to provide adequate resolution on relative abundance trends was assessed for marsh birds based on MMP data collected from 1995 through 1. The annual trend (i.e., percent change in population index based on counts) that could be detected was calculated assuming that either 1, or 3 routes were monitored over three, five, or ten years (Table 6). Although a standard has not yet been determined, many bird-monitoring specialists consider a 3% annual trend as a reasonable criterion for adequate resolution of bird trends. Assuming at least 1 routes are surveyed for 1 years, good trend resolution is expected for 15 of 33 species commonly recorded on MMP routes (Table 6). Seventyone MMP routes were surveyed annually for marsh bird routes between 1995 and 1; very few were surveyed for several years. Thus, although the net number of routes surveyed each year may be adequate, the current rate of route turnover may be problematic. Abundance indices and trends (i.e., average annual percentage change in population index) are presented for species with statistically significant trends from 1995 through 1 (Table 7). Species with significant basin-wide changes were American Bittern, American Coot, Black Tern, Blue-winged Teal, Cliff Swallow, Common Moorhen, Common Yellowthroat, Green-winged Teal, Mallard, Marsh Wren, moorhen/coot, Pied-billed Grebe, Red-winged Blackbird, Sedge Wren, Sora, Tree Swallow, Virginia Rail and Willow Flycatcher (P <.5) (Table 7A). For many species, changes in abundance indices occurred in only some lake basins. For instance, Black Terns (Figure 11A) abundance decreased significantly in Lake Huron and the Michigan-Huron basin MMP routes (P <.5), but patterns in other lake basins were relatively stable (Figure 1). Common Yellowthroat abundance increased significantly in Lake Michigan and Huron basins (P <.5) (Figure 11B). Moorhen/coot abundance decreased significantly in Lake Erie, Ontario and Michigan- Huron basins (P <.5) (Figure 11C). Pied-billed Grebe abundance decreased significantly in Lake Huron, Ontario and the Michigan-Huron basin MMP routes (P <.5). Red-winged Blackbirds and Sora abundance decreased significantly in all lake basins, except Lake Ontario (P <.5) (Figure 11 E,F). Tree Swallow abundance declined significantly in Lake Huron, Erie, Ontario and the Michigan-Huron basins (P <.5), but was generally stable in the Lake Michigan basin (Figure 11G). DISCUSSION AND CONCLUSIONS Summaries of data presented in this report are intended as an overview of the types of information contributed by MMP volunteers and to demonstrate the breadth of future analysis. Additional years of data will lead to improved resolution on trends for amphibians, birds and marsh habitat types. Since the five-year assessment was undertaken (Weeber and Vallianatos ), two additional years of MMP volunteer data

14 13 have been accumulated and we discuss below species-specific, basin-specific and basinwide trends and changes that have occurred since Routes and Habitat Route turnover by MMP volunteer surveyors, a problem experienced during earlier years of the MMP, has decreased with two additional years of data. A lesser proportion of MMP routes have been surveyed for marsh bird and amphibians for three of fewer years (68.% and 67.5%, respectively) than when last examined in Increased MMP route retention will allow for more accurate assessments of population indices and habitat associations of marsh birds and amphibians throughout the Great Lakes basin. Initial effort by MMP volunteers to survey wetland Areas of Concern (inland and coastal wetlands) when the program was initiated in 1995 has to some degree driven the spatial pattern of MMP route position. Whereas, approximately 8% of MMP survey stations were located in permanent wetlands in 1995 and 1996, this has since decreased to approximately 7% permanent wetlands and % semi-permanent wetlands. When comparing survey coverage within permanent wetland habitat among Great Lake basins, the Lake Michigan basin had the lowest coverage within permanent wetlands by MMP volunteers. This trend may be due to proportionately fewer coastal permanent wetlands in the Lake Michigan basin and the substantial urban development that has occurred along much of its southern and southwestern shoreline (D.A. Wilcox pers. comm.). Similarly, fewer MMP routes have been established in the Lake Superior basin than in other basins, perhaps due to relative scarcity of both appropriate marsh habitat and available surveyors in the region. Lake Superior has fewer suitable coastal marshes, therefore a bimodal abundance of huge or tiny wetland classes surveyed by MMP volunteers was observed. Further, a decrease in proportion of stations with open water habitat and an increase in proportion of stations with emergent habitat occurred in the Lake Superior basin over the seven years. Little information is available about habitat associations of many species of Great Lakes wetland birds and amphibians. A proficient understanding of habitat relationships among these species can be critical for understanding effective wetland management and conservation practices. When combined with information about species trends in occurrence and/or abundance, data quantifying and describing vegetation and other wetland characteristics, those wetland habitats at most risk of losing their capacity to support a diversity and abundance and marsh birds and amphibians are easier to identify. Trends in habitat composition of MMP routes may be attributed to lower basin-wide water levels since 1999/ (see Timmermans ). For instance, MMP routes have increased in coverage of emergent vegetation (i.e., cattail, grass/sedge, rushes, purple loosestrife, and common reed) substantially with two additional years of data; lake levels were low during both of these years. These results may reflect changes in habitat due to lower water levels on the Great Lakes. Amphibians Whereas this report focuses on more common amphibian species of the Great Lakes basin, other species are quite rare in parts of the Great Lakes and subsequently may require monitoring efforts more intensive than offered by the MMP. Because the

15 relationship between calling codes and numbers of individuals is uncertain, the focus of this report is on amphibian species presence (or occurrence). Due to seasonal and annual variability in populations and associated disadvantages of not detecting changes in occurrence, trend estimates for amphibians should be regarded as preliminary. The eight amphibian species commonly detected by MMP surveyors (i.e., American Toad, Bullfrog, Chorus Frog, Green Frog, Grey Treefrog, Leopard Frog, Spring Peeper, and Wood Frog) varied in their relative occurrence among lake basins. Because the range of each species extends the breadth of the Great Lakes basin, these patterns are not likely entirely due largely to range limitations. Differences in habitats, regional population densities, timing of survey visits, breeding phenology or other factors are also possible explanations. Percent station-year presence by species such as Green Frog, American Toad, Northern Leopard Frog, Chorus Frog and Bullfrog show declining trends. MMP data has detected significant declines in route occurrence for American Toad, Bullfrog, Chorus Frog and Green Frog. Although, Weeber and Vallianatos () reported declining trends for American Toad and Bullfrog, the only species that showed significant declines in the Great Lakes basin at that time was the Chorus Frog. Results with two additional years of data show significant declines in both Chorus Frog and American Toad station occurrences (3.5%/year and 1.9%/year, respectively), the latter having declined each year since the MMP commenced in Further, peaks in station occurrence were recorded for Green Frog, Northern Leopard Frog, Bullfrog and Spring Peeper during 1998 MMP route surveys, but substantial declines in occurrence has also occurred for these particular species since Most hypotheses concerning global declines in amphibian species relate to anthropogenic causes such as pollution (e.g., acid rain, pesticides), habitat destruction (e.g., urbanization, agriculture), global climate changes, and predation from introduced species (Hecnar 1997). Within the Great Lakes basin, MMP volunteer data have showed that declines in amphibian occurrence indices can vary among lake basins. For instance, apparent basin-wide declines in Bullfrog population indices appear to be driven by significant declines in the lower Great Lakes (Lakes Erie and Ontario), as significant declines were not detected in other basins. Similarly, basin-wide declines in American Toad and Green Frog population indices appear to be driven by significant declines in Lake Huron basin MMP routes. Further, declines in Lakes Michigan and Huron appear to contribute substantially to basin-wide declines in Chorus Frog occurrence indices. Results from updated power analyses show that additional years of data are likely to improve the ability of MMP data to provide trend estimates for several amphibian species, including species of conservation and management concern such as the Northern Leopard Frog and Bullfrog. Concerns about declining amphibian populations are heightened by our poor understanding of amphibian biology, particularly population and community ecology (Hecnar 1997). Even though long-term losses (195s to 199s) of such species as Chorus Frog have been recorded in the St. Lawrence River valley just outside the Great Lakes basin and population fluctuations and regional extinctions often occur (Daigle 1997), such trends may be cause for concern. Seven years of MMP survey data is a short timeframe and the low resolution on trends in amphibian station occupancy is therefore not surprising. However, annual fluctuations of amphibian occurrence indices are apparent and many endogenous and exogenous factors may be attributed to population trends. 14

16 15 Birds Although additional years of data are required to reliably estimate abundance trends of marsh birds with precision, there is merit in discussing results from preliminary analyses for those species for which sufficient data were available. With two additional years of MMP data, only Common Yellowthroat and Mallard abundance indices have continued to increase significantly. In contrast, Pied-billed Grebe, Blue-winged Teal, American Coot, moorhen/coot, Black Tern, Tree Swallow and Red-winged Blackbird continue to show significant decreases in abundance indices. Further, Sora and Virginia Rail have been added to the MMP list of marsh birds showing significant population index decreases in the Great Lakes basin MMP routes. Most of these declining species depend upon wetlands for breeding, but because of their almost exclusive use of wetland habitat, Pied-billed Grebe, American Coot, Common Moorhen, Virginia Rail, Sora and Black Tern are particularly dependent on availability of healthy wetlands. Although declines in certain wetland dependant species and increases in some wetland edge species (e.g., Common Yellowthroat) and generalist (e.g., Mallard) species suggest trends in wetland habitat conditions, additional years of data and better understanding of species habitat preferences are required to better explain such patterns. Due to the breadth of data across the Great Lakes basin, fluctuations in marsh bird indices can be narrowed down to trends occurring in specific lakes basins. For instance, basin-wide increases in Common Yellowthroat abundance indices appear to be attributed to increases in the Lake Michigan-Huron basin only. While basin-wide declines in Black Tern abundance indices appear to be driven by significant declines in the Lake Huron basin, Lakes Huron and Ontario appear to have driven decreases in Pied-billed Grebe abundance indices. Basin-wide declines in Red-winged Blackbird and Sora abundance indices appear to be driven by all surveyed Great Lake basins except Lake Ontario. Although additional years of data are necessary to assess abundance trends at the level of individual lake basins, these assessments are strongest for those lake basins in which species occur most frequently and where survey coverage is greatest. Currently, analysis of MMP bird species information provides the greatest resolution for trends in the Ontario, Erie and Huron basins but is more limited for the Michigan and Superior basins. Considerable differences are seen in marsh bird abundance indices in Lake Superior basin MMP routes as compared to the rest of the basin. For instance, Redwinged Blackbird, the most frequently detected marsh bird species in the Great Lakes basin, was detected only half as often in Lake Superior basin MMP routes. Similarly, Black Terns were never detected on Lake Superior basin MMP routes. However, Alder Flycatcher was rarely detected on MMP survey routes located outside the Lake Superior basin. This can be attributed to range and differences in physiography (Chapman and Putnam 1984) and wetland type preferences of these marsh bird species. Expected detectable annual change in relative abundance was calculated for marsh bird species and good resolution (a 3% annual detectable change) by monitoring 1 routes over a 1-year interval would be detected for several species associated with deeper water wetland habitats (e.g., Pied-billed Grebe, Common Moorhen) and many others associated with dense wetland vegetation (e.g., Virginia Rail, Marsh Wren, Common Yellowthroat, Sora, Swamp Sparrow, Red-winged Blackbird). On average, 71 routes were surveyed annually between 1995 and 1, suggesting that the current scale

17 16 may be adequate for 13 of the 7 species commonly recorded by MMP surveyors. However, monitoring on routes will be required to adequately assess trends for two species of conservation concern, Black Tern and Least Bittern (Table 6). The ecology of most marsh-dependent species has received relatively little attention and relatively little is known about rails and other secretive species (Gibbs et al. 199, Conway 1995, Melvin and Gibbs 1996). Marsh birds are believed to be sensitive to habitat disturbances, and many scientists and conservationists consider their populations to be at risk due to the continuing loss and degradation of their habitats. For instance, a substantial proportion of coastal marshes along Lake Ontario s shoreline have become choked with dense monotypic stands of cattail, likely because of reduced amplitude in water level changes (Timmermans ). Further, mean annual water levels of the Great Lakes has proven to be an important correlate and may explain much of the variation in many species trends (Timmermans ). However, marsh bird species abundance and numbers, and their activity and likelihood of being observed, vary naturally among years and within seasons. For these and other reasons, large numbers of observations, collected over many years, are required to estimate population trends reliably. Additional years of MMP monitoring data, particularly if augmented with intensive studies of individual species, will determine if patterns observed in the early stages of MMP monitoring are representative of long term, persistent population trends. RESEARCH NEEDS Extensive monitoring and broad comparisons of species trends with components of their changing environment are important to maintain and to begin addressing questions about how to better direct conservation efforts of wetland ecosystems. Such approaches often benefit from intensive experimentation to determine if observed correlations are due to cause-and-effect mechanisms. However, even improvement in extensive monitoring efforts and rigorous attempts to improve robustness of sampling design and comparative approaches can greatly improve confidence in correlative approaches. For example, obtaining geo-referenced locations of Marsh Monitoring Program route stations would greatly aid our ability to assess habitat and landscape level regimes (including water levels) through the use of Geographic Information System modelling and analyses. Such approaches would allow rigorous assessment of temporal and spatial patterns both within MMP surveyed marshes, and throughout adjacent landscapes, which can have marked affects on marsh community dynamics (Riffel et al. 1). The best way to ensure that MMP results are representative of the Great Lakes basin is to randomly sample among an inventory of available wetlands. The degree to which volunteer-selected marshes are representative of the Great Lakes basin is unknown and depends on criteria of interest. That is, population densities may not be representative if there is geographic variation across the basin in densities, or if sampled marshes are concentrated in only certain parts of the basin. Yet, population trends may be representative if selected marshes adequately correspond to the range of variation in population trends. Still, due to the volunteer nature of the surveyor-base, complete randomization of the survey is not practically feasible and may not be desirable. It may

18 17 be feasible however, to develop and implement a parallel random sampling procedure to gauge significance of the current non-random MMP sampling approach. Such a design, if implemented, should be developed in an attempt to sample habitats across their hydrologic regimes (i.e., whether they have water or are dry in a given year), which will better enable us to determine if population changes are real or apparent. Even so, such research very much depends on our ability to access a useable inventory of all Great Lakes basin marshes. Trend results for marsh birds and amphibians would benefit from a comparison with results derived from intensive species- and site-specific sampling. Such sampling could experimentally test how year-to-year changes in water level regimes of marshes affect populations by sampling at non-manipulated control sites and comparing results with those from experimental treatments under different degrees of water level control. Combining knowledge gained from such results with that gained from understanding specific habitat associations of marsh dependent birds and amphibians would greatly compliment our efforts to conserve and restore damaged and degraded wetland ecosystems for the benefit of entire marsh ecosystems throughout the Great Lakes region. Finally, trend results from the MMP should be compared against results from other monitoring programs in place in the Great Lakes basin. Cross-correlation of results across programs provides correlative evidence and support for validity of the results. there are several other regional programs in place that are collecting data on amphibian populations. It is important that these data sets are analyzed and information is shared, to enable us to validate the merit of the different programs and collectively provide more compelling results. Likewise, MMP results for marsh birds can, and should, be analyzed to determine conditions with Breeding Bird Survey results from the Great Lakes basin, at least for the most common species detected in both programs. ACKNOWLEDGEMENTS The Marsh Monitoring Program is delivered by Bird Studies Canada (BSC) in partnership with Environment Canada s Canadian Wildlife Service Ontario Region, United States Environmental Protection Agency s Great Lakes National Program Office (U.S. EPA-GLNPO), and Great Lakes United. Development and implementation of the MMP has been funded by Canada s Great Lakes Sustainability Fund, Canadian Wildlife Service, U.S. EPA GLNPO, U.S. EPA Lake Erie Team and the U.S. Great Lakes Protection Fund. The program has received important support from a variety of conservation partners, including Wildlife Habitat Canada, U.S. Geological Survey - Biological Resources Division, the Federation of Ontario Naturalists, Ducks Unlimited Canada, Ontario Ministry of Natural Resources, National Audubon Society and provincial agencies and regional conservation groups. The following organizations were particularly instrumental during early development of the MMP: Ashtabula River Public Advisory Committee, Citizens Advisory Committee for Rochester Remedial Action Plan, Hamilton Harbour Bay Area Restoration Council, International Joint Commission, Ontario Ministry of Natural Resources, Rochester Embayment Remedial Action Plan and the U.S. National Biological Service. We also appreciate support and input of the

19 18 MMP s Science and Technical Advisory Committee: Lesley Dunn (CWS), Mike Cadman (CWS), Charles Francis (BSC), Jon McCracken (BSC), Kathy Jones (BSC) and Steve Timmermans (BSC). Amy Chabot, Natalie Helferty, Ron Ridout, Russ Weeber and Mary Valiantos coordinated the MMP during earlier program development. Special thanks to Mike Cadman, Christine Bishop, and Jon McCracken for their leadership in developing the bird and amphibian survey protocols. Thank you to all MMP participants for your invaluable contributions and dedication to the program! Implementation and success of the Marsh Monitoring Program is made possible only by participation of these Great Lakes basin volunteer citizen scientists. LITERATURE CITED Anonymous. 1. The Marsh Monitoring Program- Training Kit and Instructions for Surveying Marsh Birds, Amphibians and Their Habitats. Bird Studies Canada in cooperation with Environment Canada and the U.S. Environmental Protection Agency. 4 pp. Chapman, L.J., and D.F. Putnam The Physiography of Southern Ontario. 3 rd Ed. Ontario Ministry of Natural Resources, Toronto. 7 pp. Conway, C.J Virginia Rail (Rallus limicola). In The Birds of North America. No. 173 (A. Poole and F. Gill, eds). The Academy of Natural Sciences, Philadelphia, and the American Ornithologistss Union, Washington D.C. Dahl, T. E Wetland losses in the United States 178s to 198s. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C. 1 pp. Daigle, C Distribution and abundance of chorus frog, Pseudacris triseriata, in Quebec. In Amphibians in Decline: Canadian studies of a global problem (D. M. Green, ed.). The Society for the Study of Amphibians and Reptiles, Saint Louis, Missouri. pp Gibbs, J.P., Reid, F.A. and S.M. Melvin Least Bittern (Ixobrychus exilis). In The Birds of North America. No. 17 (A. Poole and F. Gill, eds). The Academy of Natural Sciences, Philadelphia, and the American Ornithologistss Union, Washington D.C. Hecnar, S.J Amphibian pond communities in southwesten Ontario. In Amphibians in Decline: Canadian Studies of a Global Problem (D. M. Green, ed.). The Society for the Study of Amphibians and Reptiles, Saint Louis Missouri. pp Heyer, W.R., Donnelly, M.A., McDiarmid, R.W., Hayek, L.C., and M.S. Foster Measuring and Monitoring Biological Diversity: Standard Methods for Amphibians. Smithsonian Institution Press. Washington D.C. 364 pp.

20 19 Melvin, S.M., and J.P. Gibbs Sora (Porzana carolina). In The Birds of North America. No. 5 (A. Poole and F. Gill, eds). The Academy of Natural Sciences, Philadelphia, and the American Ornithologistss Union, Washington D.C. Riffel, S. K., Keas, B. E. and T. M. Burton. 1. Birds in Great Lakes Coastal Wet Meadows: Is Landscape Context Important? Landscape Ecology 16(8), in press. SAS Institute, Inc SAS/STAT software. Vers. 4.1., release 8.. SAS Institute, Inc., Cary, North Carolina. Stebbins, R. C. and N.W. Cohen A natural history of amphibians. Princeton University Press, Princeton, New Jersey. 316 pp. Snell, E. A Wetland distribution and conservation in southern Ontario. Working Paper No. 48. Inland Waters and Lands Directorate, Environment Canada. Timmermans, S.T.A.. Temporal relationships between Marsh Monitoring Program derived wetland bird and amphibian annual population indices and average annual Great Lakes water levels. Published by Bird Studies Canada in cooperation with Environment Canada and the U.S. Environmental Protection Agency. 84 pp. Weeber, R. C. and M. Valliantos.. The Marsh Monitoring Program : Monitoring Great Lakes wetlands and their amphibian and bird inhabitants. Published by Bird Studies Canada in cooperation with Environment Canada and the U.S. Environmental Protection Agency. 47 pp. Weller, M. W Management of freshwater marshes for wildlife. In Freshwater wetlands: ecological processes and management potential (R. E. Good, R. L. Simpson, and D. F. Whigham, eds.). Academic Press, New York, New York, USA. pp Weller, M. W Freshwater marshes: ecology and wildlife management, University of Minnesota Press, Minneapolis, Minnesota, USA. Weller, M. W Wetland birds. Cambridge University Press, Cambridge, United Kingdom.

21 TABLES Table 1: The number of routes surveyed in each lake basin, summarized for routes monitored for amphibians (a), birds (b) and both (ab), 1995 through 1. Overall Totals Basin a b ab a b ab a b ab a b ab a b ab a b ab a b ab a b ab Total Erie Huron Michigan Ontario Superior Group totals Year totals Table : The number and percent of amphibian and bird routes surveyed for 1 to 7 years, 1995 through 1. Number Years Amphibian Routes Bird Routes Surveyed Number % Number % Total

22 1 Table 3: Frequency of occurrence and average calling code for amphibian species detected inside Great Lakes basin MMP stations, 1995 through 1. Species are ordered by decreasing frequency of occurrence. Percent station-years present 1 Species Lake Ontario Lake Erie Lake Huron Lake Michigan Lake Superior Basin Average Spring Peeper 56.1 (.5) 65.1 (.4) 84.5 (.7) 7.5 (.5) 68.4 (.5) 68.9 (.5) Green Frog 54.9 (1.3) 58.1 (1.3) 59.8 (1.4) 43.7 (1.) 54.4 (1.3) 54. (1.3) Grey Treefrog 34.7 (.) 3.7 (1.8) 44.6 (1.8) 48.1 (1.9) 37.5 (1.7) 39.1 (1.8) American Toad 36.5 (1.5) 37.4 (1.5) 36.4 (1.5) 31.3 (1.5) 3.1 (1.6) 34.7 (1.5) Northern Leopard Frog 4.7 (1.3) 39.4 (1.3) 4.9 (1.3) 15.3 (1.) 31.9 (1.1) 3.4 (1.) Chorus Frog 17.9 (1.8).5 (1.7).3 (1.5) 49.1 (1.7) 11.9 (1.3) 4.3 (1.6) Bullfrog 9.1 (1.3) 4.9 (1.3) 1. (1.4) 11. (1.) 6. (1.) 19.8 (1.) Wood Frog 15.6 (1.6) 13. (1.5) 8. (1.5) 18. (1.5) 17.9 (1.4) 18.6 (1.5) Pickerel Frog 3.4 (1.1).8 (1.) 1. (1.).7 (1.).6 (1.).5 (1.1) Blanchard's Cricket Frog ().1 (1.) () 3.5 (1.5) 6. (1.) 1.9 (.7) Cope's Grey Treefrog 1.6 (1.6).4 (1.).1 (1.4).7 (1.) 1. (1.) 1.6 (1.3) Mink Frog 1.4 (1.). (1.).8 (1.3).8 (1.) 1.3 (1.3) 1.3 (1.) Fowler's Toad ().8 (1.3).6 (1.) 3.7 (1.1) () 1.4 (.7) 1 value in parentheses represent average calling code Table 4: Expected annual change in the proportion of stations with each amphibian species that could be detected with 1,, or 3 routes surveyed over a 3-, 5- or 1-year interval. Estimates are presented for amphibian species commonly detected on MMP routes, 1995 through 1. Number of routes 1 3 Species 3 yr. 5 yr. 1 yr. 3 yr. 5 yr. 1 yr. 3 yr. 5 yr. 1 yr. Amercian Toad Bullfrog Chorus Frog Green Frog Grey Treefrog N. Leopard Frog Spring Peeper Wood Frog

23 Table 5: Frequency of abundance and mean number of individuals of aerial foragers and marsh nesting bird species detected inside Great Lakes basin MMP stations, 1995 through 1. Species are presented by group for each lake basin and ordered by decreasing frequency of abundance for those species detected on greater than.5 % station-years. Percent station-years present 1 Group Species Lake Ontario Lake Erie Lake Huron Lake Michigan Lake Superior Basin Average Aerial foragers Tree Swallow 56.3 (5.) 6. (5.1) 49. (5.4) 6.4 (6.8) 38.6 (5.) 53.3 (5.5) Barn Swallow 3. (4.8) 8.3 (3.1) 1. (3.) 34.5 (3.8) 6.6 (.1).3 (3.4) Bank Swallow 14. (4.5) 7.5 (4.4) 3.7 (4.) (4.) 3. (3.) 6. (4.1) Purple Martin 5. (4.9) 11.3 (3.1) 1.7 (.1) 4.5 (3.3) () 4.5 (.7) N. Rough-winged Swallow 5.5 (.3) 4.9 (3.5). (3.3) 4.3 (3.1) 1. (.5) 3.6 (.9) Chimney Swift 5.1 (3.8) 5.5 (3.3).1 (1.) 4.1 (.4).6 (1.) 3.1 (.3) Cliff Swallow.1 (4.).6 (1.) 1.1 (6.8) 1.4 (.9).4 (3.9) 1.5 (3.8) Common Nighthawk. (.).4 (1.5) 1. (1.3). (5.).6 (1.) 1. (.) Marsh Nesters Red-winged Blackbird 91.5 (5.8) 94.1 (5.) 85.7 (4.5) 91. (4.9) 48. (5.) 8.1 (5.1) Swamp Sparrow 46. (.6) 46. (.) 5. (.) 41.4 (.1) 56.6 (1.6) 48. (.1) Common Yellowthroat 3.6 (1.7) 47.7 (1.6) 34.9 (1.4) 51. (1.7) 44.6 (1.4) 4. (1.6) Yellow Warbler 4.9 (1.9) 45.6 (1.7) 6. (1.6) 44.9 (1.6) 44. (1.7) 4.7 (1.7) Song Sparrow 37.9 (1.6) 43.4 (1.5) 5.6 (1.4) 36.5 (1.5) 53. (.) 39.3 (1.6) Marsh Wren 4.7 (.3) 36. (.7) 31.4 (.8) 3.4 (.) 6.6 (3.5) 9.4 (.7) Virginia Rail 31.6 (1.5) 15.3 (1.4) 34.6 (1.7).4 (1.8) 9. (1.4). (1.6) Mallard 19.7 (.4) 18. (.7) 14.3 (.3) 1. (3.9) 33.1 (7.8) 19.5 (3.8) Common Grackle 4.5 (4.) 3.9 (3.3) 1 (6.8) 1.4 (.9) 6.6 (3.9) 17.7 (4.) Moorhen/Coot 3.5 (4.1) 13.9 (3.5).1 (4.5) 8. (3.7) 1. (3.) 13.7 (3.8) Canada Goose 11.4 (4.) 11.1 (5.) 7.6 (4.) 9.6 (5.8) 1.7 (9.) 1.3 (5.6) Eastern Kingbird 1. (1.3) 1.9 (1.3) 15. (1.3) 1. (1.4).4 (1.) 1.9 (1.3) Black Tern 9.7 (.8) 1. (.3) 5.3 (6.) 8.8 (3.1) () 1.8 (.8) Pied-billed Grebe 9.6 (1.6) 8.7 (1.5) 19.3 (1.6) 1.8 (1.7) 3. (3.4) 1.3 (.) Sora 9.9 (1.) 5.3 (1.) 1.1 (1.3) 1.7 (1.) 1.8 (1.3) 1. (1.) Common Moorhen 19.6 (1.9) 8.1 (1.7) 1.1 (.3) 3.1 (1.7) () 8.6 (1.5) Alder Flycatcher 4. (1.3).3 (1.) 1.7 (1.) 1. (1.) 6.5 (.) 7.1 (1.4) Blue-winged Teal 5.4 (1.9) 1.5 (1.5) 7.7 (.1) 3.7 (1.8) 1. (1.8) 6.1 (1.8) American Bittern 6.1 (.).8 (1.1) 11.7 (1.). (1.) 3.6 (1.) 5.3 (1.3) Willow Flycatcher 7.9 (1.3) 6.6 (1.) 1.7 (1.1) 7.6 (1.1).6 (1.) 4.9 (1.1) Least Bittern 5. (1.1) 4.9 (1.1) 6. (1.).7 (1.).4 (1.) 4. (1.1) American Coot 4.7 (.) 3. (.3) 7.9 (.1) 4.5 (.) 1. (1.5) 4.3 (.) Sedge Wren 1. (1.7).7 (1.). (1.) 3.5 (1.5) 7. (.6).9 (1.6) Common Snipe 1. (1.).6 (1.1) 5.1 (1.).4 (1.1) 4.8 (1.4).8 (1.) Mute Swan 3.9 (1.6) 1. (1.9).4 (.7) 4.1 (4.5) () 1.9 (.1) Yellow-headed Blackbird ().1 (.5) () 6.3 (3.1).4 (4.) 1.8 (1.9) Green-winged Teal 1. (1.9). (1.5).1 (.).4 (1.3) 3.6 (5.3) 1.5 (.4) American Black Duck.8 (3.).3 (1.6) 1 (1.9) () 3.6 (4.5) 1.1 (.) Sandhill Crane ().6 (1.9) 1.5 (.4). (.3) 1. (.) 1.1 (1.7) Ring-necked Duck.3 (3.).1 (3.).7 (1.6).6 (.) 3. (.8).9 (.5) Northern Shoveler. (1.) () () () 4. (.3).9 (.7) Forster's Tern.1 (.) 3.8 (1.5) ().4 (1.5) ().9 (1.) American Wigeon ().1 (1.).4 (1.3) () 3.6 (.).8 (.9) Northern Harrier 1.7 (1.1).5 (1.5).3 (1.) () 1. (1.5).7 (1.) 1 vaules in parenthese represent average count

24 3 Table 6: Estimated percent annual change in abundance index (based on counts inside standard MMP station boundary) that could be detected with 1,, or 3 routes surveyed over a 3-, 5- or 1-year interval. Estimates are presented for the aerial foraging and marsh nesting bird species commonly detected on MMP routes, 1995 through 1. Number of routes 1 3 Species 3 yr. 5 yr. 1 yr. 3 yr. 5 yr. 1 yr. 3 yr. 5 yr. 1 yr. Alder Flycatcher American Bittern American Coot Bank Swallow Barn Swallow Black Tern Blue-winged Teal Canada Goose Chimney Swift Cliff Swallow Common Grackle Common Moorhen Common Nighthawk Common Snipe Common Yellowthroat Eastern Kingbird Least Bittern Mallard Marsh Wren Moorhen/coot Mute Swan N. Rough-winged Swallow Pied-billed Grebe Purple Martin Red-winged Blackbird Sedge Wren Sora Song Sparrow Swamp Sparrow Tree Swallow Virginia Rail Willow Flycatcher Yellow Warbler

25 4 Table 7A. Annual abundance indices and trends in marsh bird populations throughout the Great Lakes basin, Annual AbundanceIndices Trend Lower Upper Species P 1 (%/yr) 95% C.I. 95% C.I. P ALFL AMBI ** * AMCO ** ** BANS ** BARS BLTE ** ** BWTE ** CAGO CHSW * CLSW ** ** COGR ** COMO * CONI * COSN ** COYE * ** EAKI FOTE GWTE ** ** LEBI MALL ** ** MAWR ** * MOOT ** ** MUSW * NRWS * PBGR ** ** PUMA RWBL ** ** SACR SEWR * * SORA ** ** SOSP SWSP TRES ** ** VIRA ** ** WIFL * YWAR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1.

26 5 Table 7B. Annual abundance indices and trends in marsh bird populations within the Lake Michigan basin, Annual Abundance Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P BARS * CAGO ** * COGR COYE * * EAKI MALL ** MAWR * MOOT ** ** PBGR * RWBL SORA ** SOSP SWSP TRES ** VIRA ** WIFL * YWAR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * - statistically significant at P <.5. ** - statistically significant at P <.1.

27 6 Table 7C. Annual abundance indices and trends in marsh bird populations within the Lake Huron basin, Annual Abundance Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMBI AMCO BARS * BLTE ** ** BWTE CAGO * COGR ** COMO COSN * * COYE EAKI MALL ** MAWR MOOT PBGR ** ** RWBL ** ** SORA ** ** SOSP SWSP TRES ** ** VIRA YWAR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1.

28 7 Table 7D. Annual abundance indices and trends in marsh bird populations within the Lake Michigan-Huron basins, Annual Abundance Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMBI AMCO * BANS BARS ** BLTE ** ** BWTE * CAGO ** COGR ** COMO COSN COYE ** ** EAKI LEBI * MALL ** MAWR MOOT * NRWS PBGR ** ** PUMA * RWBL ** ** SACR SEWR SORA ** ** SOSP * * SWSP TRES ** ** VIRA ** WIFL YWAR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1.

29 8 Table 7E. Annual abundance indices and trends in marsh bird populations within the Lake Erie basin, Annual Abundance Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMBI AMCO ** BANS ** BARS BLTE BWTE CAGO CHSW COGR ** COMO COYE EAKI * FOTE LEBI MALL MAWR ** ** MOOT ** ** NRWS PBGR ** PUMA ** RWBL ** ** SORA ** * SOSP * SWSP TRES ** ** VIRA ** ** WIFL YWAR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * - statistically significant at P <.5. ** - statistically significant at P <.1.

30 9 Table 7F. Annual abundance indices and trends in marsh bird populations within the Lake Ontario basin, Annual Abundance Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P ALFL AMBI BANS BARS BLTE * BWTE CAGO CHSW ** COGR ** COMO COYE EAKI LEBI MALL MAWR MOOT * MUSW NRWS ** PBGR * ** PUMA ** RWBL SORA SOSP SWSP TRES * VIRA * WIFL YWAR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1.

31 3 Table 8A. Annual occurrence indices and trends in calling amphibians throughout the Great Lakes basin, Annual Ocurence Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMTO ** BULL * CGTR ** ** CHFR ** ** FOTO ** GRFR ** ** GRTR * MIFR NLFR ** PIFR * * SPPE ** WOFR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1. Table 8B. Annual occurrence indices and trends in calling amphibians within the Lake Michigan basin, Annual Occurrence Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMTO BULL CHFR ** ** GRFR ** GRTR ** NLFR ** SPPE * WOFR ** P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * - statistically significant at P <.5. * * - statistically significant at P <.1.

32 31 Table 8C. Annual occurrence indices and trends in calling amphibians within the Lake Huron basin, Annual Occurrence Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMTO ** ** BULL ** ** CHFR ** ** GRFR ** ** GRTR NLFR SPPE ** WOFR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * - statistically significant at P <.5. ** - statistically significant at P <.1. Table 8D. Annual occurrence indices and trends in calling amphibians within Lake Huron-Michigan basin, Annual Occurrence Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMTO ** ** BULL * ** CHFR ** ** GRFR ** ** GRTR NLFR PIFR SPPE ** ** WOFR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1.

33 3 Table 8E. Annual occurrence indices and trends in calling amphibians within the Lake Erie basin, Annual Occurrence Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMTO BULL * ** CHFR GRFR GRTR NLFR ** ** PIFR SPPE ** WOFR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1. Table 8F. Annual occurrence indices and trends in calling amphibians within the Lake Ontario basin, Annual Occurrence Indices Trend lower upper Species P 1 (%/yr) 95% C.I. 95% C.I. P AMTO * BULL * * CHFR * GRFR ** GRTR NLFR * ** SPPE ** * WOFR P 1 - probability that significant year-to-year variation in population index occurred. P - probability that population index trend between differed from zero. * ** - statistically significant at P <.5. - statistically significant at P <.1.

34 33 FIGURES Figure 1. Location of MMP routes (birds and amphibians) throughout the Great Lakes basin