Iron County Loon Project Practicum in Loon and Lake Ecology and Management Final Report 2015

Transcription

1 Iron County Loon Project Practicum in Loon and Lake Ecology and Management Final Report 15 Background For the more than years, the Wisconsin Department of Natural Resources (WDNR) Bureau of Integrated Science Services has conducted research on the potential impacts of mercury on loon populations in northeastern Wisconsin. This work has examines causes of loon productivity decline on a number of lakes in Iron, Vilas, Oneida and Forest Counties. Results of this study are pending, but initial findings suggest that loons nesting on high mercury, low ph lakes have reduced chick production and survival. In addition, this study has looked at the impact of habitat loss on loon populations. One finding of this work is that loons living on small lakes where there are no islands have reduced production of chicks. To combat this decline in nest success, artificial nesting platforms have been placed on lakes where loons have had trouble successfully reproducing, resulting in chick production doubling. The WDNR is considering ways to manage and maintain platforms on target lakes. The WDNR approached Iron County with the idea of piloting a citizen-monitoring program for platforms. The concept for the Practicum in Loon and Lake Ecology came

2 out of this discussion, with Hurley and Mercer students involved in a pilot during the spring and summer of Students constructed nesting platforms; selected study lakes based on water quality and habitat features, and placed and monitored the platforms in spring and summer. To date, this program has been monitoring lakes health and loon production for over 16 years. The students work has resulted in many successfully hatched loon chicks from the artificial platforms that they have constructed and place out for loons to use in Iron County, WI. The physical data for each of the lakes involved in the project are shown in Table 1. Lakes varied in public ownership from nearly 1% to none. All of the lakes are either seepage or drainage lakes within the Mississippi River and Lake Superior watershed. Shoreline development varies, with students ranking two lakes as low percentage of shoreline developed and the other three medium or high leveled developments. It should be noted that none of the lakes are as highly developed as lakes found in more southerly regions of the state and student rankings on development are comparative only in Iron County. Table 1. Physical Lake data Iron County, WI. Lake Name Estimated % Public Ownership Acreage Max Depth Watershed Basin Sub Watershed Lake type % Shoreline Developed Pardee 6 7 Lake Superior Montreal River Drainage Medium Fox 6 3 Mississippi Turtle Flambeau Seepage Low Deer Mississippi Turtle Flambeau Seepage Low Grand Portage 1 31 Mississippi Turtle Flambeau Drainage Medium/High Hewitt Mississippi Turtle Flambeau Drainage Low-Medium Gile Lake Superior Montreal River Drainage Medium Goals Provide Iron County teachers with cost effective and practical assistance in meeting curriculum needs in environmental education, water quality, aquatic habitats and wildlife management Increase students understanding and appreciation of water resources, aquatic and riparian habitats, loon ecology, and issues relating to management of natural resources Increase outdoor skills of Iron County school students Assist Iron County Forest, the LCD Land and Water Resource Plan and WDNR in meeting education priorities Test methods for increasing loon chick production on Iron County Lakes Objectives for Student Learning Students will learn methods for studying water quality and will test water chemistry on study lakes

3 Students will learn about the natural history, ecology and management of common loons Students will be able to explain current issues relating to loon protection and habitat management Students will learn methods for sampling invertebrates Students will construct artificial nesting platforms for common loons Students will assess lake habitats and historical loon use and will select locations for platforms Students will place platforms on lakes and will monitor loon presence, nesting, and chick production Students will learn computer data management and analysis and presentation skills Methods In the 15 field session, 15 high school students from Hurley and 9 eighth grade students from Mercer participated in the program. Throughout the years students constructed artificial nesting platforms in shop classes. Each platform followed the construction model developed by the WDNR. Students received a training session on loon ecology, habitat needs and threats to loon nesting success such as lakes with high acidity and the presence of heavy metals. Students then selected lakes for platform placement and platforms were placed on Fox, Deer, and Grand portage Lake with Mercer in mid-may and on Pardee, Hewitt, and the Gile with Hurley. Little Pike Lake, near Mercer, was also a project lake, however, due to time restrictions lake property owners maintained the platform and conducted water PH, secchi and dissolved oxygen tests. In addition to platform study lakes the project observed Pine Lake and the Gile Flowage for nesting and chick production. This year had a normal ice off date. During the spring field trip, in addition to placing artificial loon nesting platforms, students collected data on watershed size and characteristics, dissolved oxygen, temperature, ph, water clarity, and conducted a survey for marcro-invertebrates. They used field chemistry test kits, secchi disc, topographic maps and water surface inventory books to help analyze the lakes physical and chemical makeup. Data was recorded on a lake profile data sheet. Loon presence and behavior was also recorded on a separate loon presence data sheet. Six artificial loon platforms were placed this year. Return trips to the lakes were conducted in June, July and August. Water quality, water clarity and marcro-invertebrate tests were repeated at return visits. In addition, shoreline buffer transects (June) and aquatic vegetation transects (July) were completed on subsequent

4 visits. Loon presence, nesting status, chick production and chick survival and the presence or absence of predators were also noted at each visit. This year the students took on a new challenge and placed trail cameras on both natural and artificial nest platforms to record nesting status and any presence of predators or other nesting issues that may impact nesting success. Results and Discussion Loon Production Loons are known to utilize natural and artificial nests on both developed and undeveloped lakes. Out of six platforms placed, loons utilized five of the platforms. The Gile Flowage sub-pond was not used this year. Pardee, Fox, Deer, Grand portage, and Hewitt Lake platforms were used but only produced a total of two chicks. Grand portage was the only lake that successfully produced chicks from the platform however lake residence witnessed eagles killing both chicks. The Gile Flowage sub-pond pair hatched two chicks on the first nest attempt and Hewitt Lake loons started out on the platform however was predated on and re-nested naturally and produced one chick. For Hewitt this was the first natural nest success in many years. Egg shell fragments were observed on the Hewitt Lake nest platform suggesting predation during the first nest attempt. Out of a total possibility of 1 chicks on both natural and artificial nests, two chicks hatched off of the platforms and three chicks hatched naturally, making chick production 1% successful on platforms and % successful naturally. Loons on Little Pike nested naturally however failed and did not produce a chick. In conclusion, the results from this year s loon research were quite unusual compared to past data. With the normal ice out conditions, lack of black flies, and five out of six nest platform used, we were expecting a higher chick production. Camera work on artificial nest platforms will continue next year in hopes of understanding why platforms nest are failing. Nest Camera Results: Predators and other disturbances Pardee Lake Nest This year we placed three trail cameras at loon nest sites. All three cameras were attached to artificial nest platforms from Mid-May through the nesting season. The results from the camera study were very interesting and educational. The Fox Lake camera showed nest building, copulation and egg laying however the nest was later abandon. Hewitt Lake also showed nest building, copulation, and egg laying however the nest was predated on and the batteries in the camera had died before the event resulting in

5 no photos of any predators. During the first two weeks at the Pardee Lake camera muskrat and Canada geese appeared at the nest cup but later the loons nested, laid two eggs and also abandoned the nest. The camera also documented both male and female sharing incubation and egg turning. Nest abandonment occurs time to time on both developed and undeveloped lakes and on both natural and artificial substrates. Lakes with successful nesting ranged from slightly acidic to basic, and water clarity varied. Platforms were most successful where there was a history of previous failed nest attempts and platforms were placed directly next to the historical site. Platforms placed in seemingly good locations, but not directly adjacent to the natural site were not used. On lakes where platforms were successful, in-depth information from landowners and researchers was utilized in selecting platform locations. Loons are known to use the same nesting sites year after year, even selecting the same nest cup location from time to time. This suggests that in future years, platforms be located as close to historical sites as possible. Natural Artificial (Deer Lake Natural Nest) (Hewitt Lake Platform) Table. Loon nesting success 15 Lake Name Nesting (y/n) # Chicks produced # Chicks at late summer visit Pardee Y, Platform / natural Fox Y, Platform, Grand Portage Y, Platform Deer Y, Natural, Abandon Little Pike Y, Natural, Predated Gile Flowage Y, Natural Hewitt Y, Natural 1 1 Total 7 Lakes 5 3

6 Crystal Deer Fox Grand Portage Pardee Gile Flowage Little Pike Pine Hewitt # of Chicks # OF CHICKS Figure 1. The below charts represent chick production since the project begun in Loon Chick Production (without platforms) Crystal Deer Loon Chick Production (with platforms) Fox Grand Portage Pardee Gile Flowage Little Pike Pine Hewitt Water quality Students collected the following water quality measurements at each of the three visits: dissolved oxygen, ph, water clarity and surface temperature. In addition, students collected samples of macroinvertebrates at each visit and marcophytes on the third visits as indicator of water quality. Water quality reading help give an overall estimation of aquatic water quality. Water quality readings help give an overall estimation of aquatic ecosystem health, and therefore, the suitability of a water body for loon nesting. Water quality on study lakes is summarized on Table and all samples were taken near shore. Dissolved Oxygen: Dissolved oxygen (DO) is a factor in loon nesting success due to its effect on their main forage base, the fish and macroinvertebrate community. Most fish prefer DO reading of 7-9 mg/l for optimal survival, and most will cease to exist in less than 3mg/L.

7 : Table 3. Dissolved oxygen in loon study lakes 15, Iron County, WI. Dissolved Oxygen Reading 15 Dissolved Lake Name Oxygen (mg/l) Average DO (3 visits) Dissolved Oxygen (Min- Max) Range Fox 9. Total: 5.1 Min: 8. Range: 1. Yes Max: 9. Deer 7.8 Total: 3.6 Min: 7.8 Range:. Yes Max: 8. Grand Portage 8.98 Total: 5.6 Min: 8. Range:.98 Yes Max: 8.98 Pardee 1. Total: 5.5 Min: 7. Range: 3. Yes Max: 1. Hewitt 9. Total: 6. Min: 8. Range:.8 Yes Max: 9. Analysis: Dissolved oxygen readings were suitable for nesting loons on each of the study lakes ranging from 7. at Pardee Lake to 1. also on Pardee Lake. Interestingly, Pardee Lake is the only lake with a range of 3. and also is the most diverse lake with aquatic plants. Figure. Dissolved Oxygen in loon study lakes in 15, Iron County, WI. Suitable for loons nesting? Y/N 1 Disolved Oxygen Fox Deer Grand Portage Pardee Hewitt

8 Feet Waters Clarity: Because loons are sight feeders, water clarity is of the utmost importance for nesting success. High clarity readings mean ease of finding and capturing food for themselves and for feeding and training chicks, thus making the lakes with higher clarity more likely to support successful loon reproduction and raring. Table. Water clarity (Secchi disc) in 15 in loon study lakes, Iron County, WI. Lake Name Visits Secchi (ft) Average Secchi (3 visits) Min - Max Range Suitablity for Loons Percent chance of success Fox 1 st visit: 3 Total: 9. nd visit:. Min: Range:. Poor <% 3 rd visits: 3 3. Max:. Deer 1 st visit: 6 Total:18.5 Min: 5.5 Range: 1.75 Good % nd visit: 7 3 rd visits Max: 7. Grand Portage 1 st visit: 5.5 Total: Min: 5.5 Range: 3.5 Good % nd visit: rd visits Max: 9. Pardee 1 st visit: 6 Total:3.5 Min: 6 Range:. Good % nd visit: 1 3 rd visits Max: 1 Hewitt 1 st visit: 17 Total:51 Min: 17 Range:. Great 8% nd visit: 17 3 rd visits Max: 17 Analysis: Hewitt Lake had the highest water clarity reading with a Maximum of 17 feet, an average of 17. feet and was successful hatching a chick. Fox Lake once again had the lowest with an average low of 3.. Pardee Lake was the most variable with a difference of. feet from the 1 st to 3 rd visits. For reasons unknown to us Deer Lake s clarity has improved several feet over the last years and Fox Lake has decreased. Both are seepage Lakes and about the same size. Fox Lake has some minor development but shouldn t be a major factor. Fox Lake Secchi Years

9 : Feet Figure 3. Water Clarity (Secchi disc) in 15 in loon study lakes, Iron County, WI. Water Clarity Fox Deer Grand Portage Pardee Hewitt Lake and Visit Acidity (ph): Northern lakes are especially acidic due to atmospheric deposition and from tannins from pine trees and bogs. High acidity makes mercury and other heavy metals more readily absorbed into the flesh of animals. Fish pick up these toxins and loons eat the fish. Mercury is metabolized in the system of loons and can cause central nervous system damage and affect their eyesight. In addition, high acidity (low ph), correlates with less marcroinvertabrates in the system, resulting in less food for loon chicks. Therefore, the optimal ph range for loon production is from (around neutral).

10 Table 5. Acidity (ph) in 15 loon study lakes, Iron County, WI. Lake Name Acidity (ph) Average ph PH reading Min - Max Range PH Suitability for loons: (Total /3) (min-max) Critical <.3, Suboptimal.-6, Optimal Fox 6.8 Total:.8 Min: 6.8 Range:.13 Optimal Max: 6.93 Deer 6.93 Total: 19. Min: 6. Range:.9 Slightly Optimal Max: 6.9 Grand Portage 6.3 Total: 1.75 Min: 6.3 Range: 1.5 Optimal Max: 7.75 Pardee 7.7 Total: 3. Min: 7.5 Range: 1.5 Optimal Max: 8. Hewitt 6.5 Total: 19.5 Min: 6.5 Range:.5 Slightly Optimal Max: 6.5 Figure. Acidity (ph) in 13 loon study lakes, Iron County, WI. Shoreline Buffer and Aquatic Plant Survey

11 Shoreline buffer strips and aquatic plant transects were conducted on all 5 lakes during the third visit. In general, this data was taken as a general indication of the lake health and the ability of a shoreline to provide a substantial buffer for pollutants, and other toxins entering the water body. Shoreline buffers also provide habitat for fish and macroinvertebrates which loons feed on. Because shoreline data were collected for convenience sake at our lake access points which were human-impacted homes and boat landings, the data were naturally skewed, offering only a snapshot of shoreline status, not an overall indication of buffer zone health. We used this information as a foundation of a discussion with the students about the importance of retaining natural buffer zones and the effects that altering shoreline areas can have on lake health and loon reproduction. In general, our data show less developed lakes had more complete and healthy shorelines, which aligns with previous WDNR research that found that development of shorelines significantly reduces the shrub layer and amount of dead and down woody debris. Table 6. Shoreline buffer transects (Nearshore) in 15 loon study lakes, Iron County, WI. Lake Name Average % Average %Shrub Average % % Woody Debris Understory Cover Cover Canopy Fox 51.5 Medium Deer Medium Grand Portage Low Pardee Medium Hewitt Medium Table 7. Littoral zone macrophyte transect (aquatic plant survey) in 15 loon study lakes, Iron County, WI. Lake Name Average % Cover Substrate % Woody Debris Fox 9 Muck Medium Deer 1 Muck Medium Grand Portage 1 Sand and muck Low Pardee 6 Sand and gravel Low Hewitt.89 Sand and muck High

12 Conclusions and Discussions Students planned, constructed, and monitored loon nesting on 7 lakes in Iron County. 5 of the 6 platform lakes were used by loons however only 1 produced chicks. This is probably our lowest success rate since the start of the project. Several factors, weather and a late ice off, may have played a large role in the poor success. Hewett Lake was a new addition to the project and with continued platform placement; we feel that this lake has a lot of potential. If ice conditions and extreme weather changes continue in the Northwood s, loons may be impacted and work such has the practicum in loon and lake ecology and management research project will be a major benefit to the loons and lakes of Iron County. Students responded positively to the project and many volunteered their time during the summer break. They became proficient at selected chemistry testing, loon identification and behavior and gained experience in canoeing and water safety. They were exposed to issues relating to shoreline development, erosion control, invasive species, and buffer preservation and we feel that they have a great insight on the overall story of loons and lakes in Iron County. Thank you for your support