MANAGEMENT PLAN FOR BIOLOGY 344, WILDLIFE BIOLOGY

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Authored by  Karianne Wold & Vanessa  Smith

The Blanding's turtle (Emydoidea blandingii) and the Northern Leopard Frog  (Rana pipiens) have been on the threatened species list of many areas within their ranges due to loss of habitat and other decimating and welfare factors directly or indirectly related to humans.  Many organizations in both Canada and the United States are starting and/or maintaining conservation programs to protect both species from becoming extinct.  The management project to be described in the following pages is designed with the intention to provide new habitat for primarily the Blanding's turtle and secondarily the Northern Leopard Frog.  The area to be managed is within the property boundaries of the Carpenter Nature Center in Hastings, Minnesota.  The location of the management project was chosen because it is currently being assessed by the Minnesota Department of Transportation (DOT) as a possible moving site for a present wetland in order to make room for a larger highway.  Therefore, the the DOT is responsible for the entire expense of constructing a new wetland (which makes the remaining expenses very economically feasible).  Creating a new habitat for Blanding's turtles and leopard frogs enhances the populations of these threatened species.  If constructed with an educational theme which is the main goal, visitors to the Carpenter Nature Center will learn all about two of the threatened species living in their state and what they could do to prevent contributing to the decimating and welfare factors that cause the current status of many animal populations.

EMYDOIDEA BLANDINGII

STATUS OF BLANDING'S TURTLE

The Blanding's turtle is currently on the Threatened Species list throughout its range; much effort is being put into reestablishing its population.  A mixture of decimating and welfare factors are the reasons this turtle is of threatened status:  these include loss of habitat (less food and water availability), increased edge of habitat (more vulnerable to predators), and fragmentation of habitat (roads going through habitat - cars kill many of the turtles during breeding time) (Ernst 1994 and Bergland Handout 1997).  

RANGE AND HABITAT OF BLANDING'S TURTLE

Emydoidea blandingii, or Blanding's Turtle, ranges from southwestern Quebec and southern Ontario south to southeastern Minnesota  (and down to Illinois and north-central Nebraska) and west to northwestern Pennsylvania (Nova Scotia).  They prefer eutrophic habitats that contain a clean, shallow water body that has a firm, organic bottom that is abundant with aquatic vegetation.  A study done in Wisconsin in 1990 by Ross and Anderson showed that Emydoidea spend most of the time in marshes rather than ponds, and ponds with sandy bottoms and no aquatic vegetation are rarely used.  Ross and Anderson also found that wetlands covered with cattails are not used; only areas cleared of cattails by muskrats are entered.  Studies performed in Minnesota by Pappas and Brecke in 1992 showed that small juvenile Emydoidea use primarily emergent sedge habitats and alder hummocks.  Larger juveniles use sedge/water interfaces; the largest juveniles are found in open water (Ernst 1994).  

BEHAVIOR OF BLANDING'S TURTLE

Emydoidea are diurnal.  Some studies show that Emydoidea has terrestrial tendencies except during breeding season. Male turtles tend to travel farther (range of 0.57 hectares to 0.94 ha) in search of new aquatic habitats than females, whose trips are shorter (average of 0.64 ha) and associated with nesting (Ross and Anderson in Ernst, 1994).  

Emydoidea's longevity of hibernation varies with the area it lives in.  In general, when water temperatures are 6-13 degrees Celsius, the turtles enter their overwintering sites.  The studies performed in Wisconsin showed that the turtles there hibernate in the deepest parts of ponds and creeks with organic substrates.  The dormant turtles lie partially buried at an average water depth of 0.9 meters.  Usually, Emydoidea hibernates relatively close to its summer habitat (Ross and Anderson in Ernst, 1994).   

REPRODUCTION OF  BLANDING'S TURTLE

Studies performed in Wisconsin have shown that females mature at the minimum age of 18 years, or when their plastron length is 17 centimeters.  Males mature at an earlier age of 12 years old, or when their plastron is 18-19 centimeters in length (Ross 1989a in Ernst, 1994).  Because of this delay of sexual maturity, and the fact that very few of the hatchlings survive to maturity because of predation and other decimating factors, they are considered to be a K-selected species (Bergland Study Guide1997).   The clutch sizes average 10-15 eggs (Rowe, 1992; Congdon and van Loben Sels, in press in Ernst 1994).  The sex of the hatchling is temperature dependent (lower temperatures of the nest produce more males).  This welfare factor is critically important to the survival of the population of turtles because if the temperature  of the nest is too high or too low, only one sex of hatchlings is produced.  

LONGEVITY OF  BLANDING'S TURTLE

The lifespan of Blanding's turtles is about 75 years (Nova Scotia).  The oldest living individual was found in Minnesota and was approximately 77 years old (Brecke and Moairty in Ernst, 1994).  This factor also determines the classification of Emydoidea as a K-selected species (Bergland Study Guide1997).

FOOD HABITS OF BLANDING'S TURTLE

     Generally, Emydoidea feeds for only 4.5 months.  The dominant prey is the crayfish (50-75%), but insects (Odonata, Trichoptera, Coleoptera, Diptera, Orthoptera), fish and their eggs, frogs (Rana catesbiana), and plant material (filamentous algae and duckweed) are also ingested.  When terrestrial, they eat grasses, leaves, berries, slugs, grubs, insect larvae, and earthworms (Ernst 1994).

PREDATORS OF BLANDING'S TURTLE

The largest threat to Emydoidea is man-made roads near their habitat:  they cross these roads, usually between wetlands and uplands, for breeding purposes and are run over by unsuspecting drivers.  Humans are the cause of another decimating factor of Emydoidea;  there is a loss of habitat and and increase of ecotones (edge) of what habitat is left.  The nests located on these ecotones are much more vulnerable to predators, such as raccoons, foxes, skunks, and opposums (Ernst 1994).  

OTHER POSSIBLE SPECIES

RANA PIPIENS

Like Emydoidea, the population of Rana pipiens, commonly called the leopard frog, is also seriously declining (Petit 1992).  Many contributing factors to the declination of the leopard frog are caused by humans, such as "habitat destruction, fire suppression, increases in ultra-violet radiation, industrial pollution, pesticides, acid precipitation, sedimentation, changes in temperature, introduction of predators or competitors into breeding areas," but there are also natural decimating factors such as diseases and natural population fluctuations (The Northern Leopard Frog).      The leopard frog is native to Minnesota, and they are not hard to manage for because they do not need such a large range to prevent them from wandering.  Also their diet is simple:  the tadpole diet consists of algae and other plant matter, and the adults consume large amounts of insects.   The leopard frogs' habitat can include marshes, meadows, and ponds.  Leopard frogs must return to open water during breeding season, but the rest of the year they may stray far from water (Northern Leopard Frogs).  

"HABITAT BORROWERS"

Other species that may benefit from the newly designed wetland include deer, other types of frogs, mallards and wood ducks, several non-game birds, and other migrating waterfowl.

Since the Blanding's turtle was added to Minnesota's threatened species list in 1984, many different practices have been tested. Not much was known about the Blanding's turtle previous to these management practices. The Blanding's turtle is an extremely vulnerable species. Because of increasing populations of predators, nest mortality often exceeds 90%.  With an increase in limiting factors such as road mortality, wetland loss, and isolation of populations, vulnerability is magnified (Maine Endangered Species).

One attempt to control predation of the nest has been to closely monitor the turtles during the period when they are going to lay their eggs; someone then places a screen box over the nest.  Later, when the turtles have hatched, the nest boxes are removed (Morrison 1995).

"Operation Turtle Rescue" is one project which has formed in Minnesota. For this project, volunteers meet at a road which has been built between the turtles nesting site and their protective wetland. The volunteers then proceed to find turtles and carry them across the road. By doing this, they hope to reduce turtle mortality from automobiles (Abraham 1995).

Cornell University is conducting a headstart program in which juvenile Blanding's turtles are raised in captivity for a year. While in captivity, these turtles are fed an accelerated-growth diet. By the time these turtles were ten months old, they were the size of four year old turtles. Ecologists at Cornell hope that the turtles will reach sexual maturity sooner, and help replace "missing generations" of egg laying turtles in the wild (The Blanding's Turtle - A Case Study).

An area in Nova Scotia, Canada is also doing a headstart program. In this program, the turtles are being studied after they are released. In the study, it was found that the turtles showed a lot of movement until they were able to find a suitable habitat. The turtles moved away from streams and open water and settled in shallow water which had a continuous thick layer of sphagnum moss. This study suggests that individual turtles preferred terrestrial microhabitats to aquatic environments (Morrison 1996).

Carol Jean Dorff performed a large study on the effects of habitat fragmentation on Blanding's turtle populations within metropolitan Minnesota, and impacts to this species resulting from a controlled wetland drawdown (1995). Dorff found that habitat mosaics which include shallow emergent marshes and expansive grasslands provide important habitat features, yet barriers such as high use roads and railroad tracks fragment the habitat and can result in extirpation of affected populations (1995). Blanding's turtles utilize openings within cattail stands, but do not occupy full-vegetated wetlands (Ross and Anderson, 1990 in Dorff 1995). Dorff also noticed that turtle density increased with an increase in grassland (1995). Blanding's turtles nest in grasslands 6 hectares in size or larger (Ross and Anderson, 1990 in Dorff, 1995). Management sites should have central wetlands which consist of 15%-40% open water, and are surrounded primarily by grassland habitat (>60%)(Dorff, 1995). While Dorff studied the effects of a fall drawdown, she found it had detrimental results. Many of the turtles emigrated from the wetland and became vulnerable to predation, disease, and mortality caused by stress and injury (1995). If turtle mortality rates could be reduced, potential benefits could be gained from increased invertebrate populations, and greater interspersion of water and emergent vegetation (Dorff, 1995).

According to Section 404 of the Clean Water Act, when a wetland is destroyed another wetland of equal or greater size must be created. There is a 10 acre (4 hectare) wetland located near Prescott which is planned to be destroyed in the future for the expansion of the nearby highway. The Department of Motor Vehicles (DMV) is searching for possible locations to create a wetland to replace the one that is being destroyed. One area they are assessing is located at Carpenter Nature Center, and this is where we decided to do our management plan.

The area we will be managing is located in the SW 1/4 of section 4, and the NW 1/4 of section 9, Denmark township, Washington County. This land is owned by Carpenter Nature Center (CNC), a private, non-profit facility. While CNC owns over 400 acres (160 hectares) of land, the area we will be managing consists of approximately 15 acres (6 hectares). These 6 hectares are located at the entrance of the facility, with part of it on either side of the driveway.

According to Mayme Johnson, an interpretive naturalist at CNC, this area was previously a managed apple orchard (1997). Originally, this land was probably prairie and may have been used agriculturally. About 20 years ago, the orchard was dug up and allowed to grow naturally. A small portion of the land was constructed into a man-made pond. Because no type of lining was used on this pond, it only has water for a short period of time in the spring. During this time, the pond is used by a variety of species including dragonflies, toads, frogs, mallards, wood ducks, raccoon and deer. For the rest of the year, this area as well as the rest of our area is covered in grasses, goldenrod, thistle, aster, smartweed, wild raspberries, and other herbaceous plants (Johnson 1997).

The predominant soil type in this area is Lindstrom silt loam with a 2-4% slope (labeled 301B). Other soil types in this area include Channahon silt loam (labeled 472C) ,and Ripon silt loam (labeled 529B). All of these soils are moderately permeable (Soil Survey 1980). The west side of our current management area is bordered by Highway 21. Across the highway is over 100 acres (40 hectares) of restored prairie also owned by CNC. To the South of our area is an apple orchard owned by CNC's neighbors. To the east is a small strip of Colorado Blue Spruce followed by CNC's own apple orchard. The north side of our area is bordered by forested land which includes a major ravine that empties into the St. Croix River.

The first year of our plan will consist mainly of construction of the area. We plan to start in the fall of the year to reduce impact on the neighboring areas and vegetation. We will begin by removing the current trail on the north side of the driveway. We plan to leave the trail on the south side of the driveway the way it is. Next, we will construct three ponds. The areas that the ponds are to be located will have to be dug up because the area is fairly level at this time. We will build two ponds on the south side of the of the driveway, one on each side of the trail, and another pond on the north side of the driveway. They will be constructed so that they will slope downward toward the north. Between each pond, we will construct a vegetated spillway to allow normal runoff to escape from the ponds (Payne 1992). The most northern pond will drain into the ravine on the northern end of the plot of land. These vegetated spillways will also act as travel corridors for the Blanding's turtles from one pond to another. We will construct a culvert that will go under the driveway to create a continuous spillway between the ponds. This culvert will also provide a route for the turtles to the other pond(s) without having to cross the driveway . The edge of these ponds will be built with a 6:1 slope to ensure more area for emergent vegetation (Halverson 1997). The larger pond will be the deepest:  it is called the “home pond” because this is where the turtles hibernate and breed. This pond is used primarily during the winter, so it needs to be deep enough to not freeze completely (Levell  Interview1997). The larger pond will have a maximum depth of five feet. This depth will help in the prevention of the pond completely freezing to the bottom in the winter. Also, the Turtles usually hibernate at depths of 0.9 meters (Ernst 1994). The other ponds will have maximum depths of three feet. These remaining ponds are dubbed “staging ponds” and are used for feeding. These ponds do not have to be very deep – some may even dry up during the summer (Levell Interview 1997).  

Because the of the types of soil found in this area, we will have to place a lining on the bottom of the ponds. We have decided to use a clay blanket which is a mixture containing at least 20 percent clay by weight. The clay blanket will be spread in even layers 15 - 20 cm thick. To prevent the clay blanket from cracking due to freezing and drying, a cover of gravel 30 - 46 cm thick will be spread over the clay blanket (Payne 1992). Since the gravel will not be good soil for growing vegetation, we will haul organic substrate from the wetland in Prescott that is to be destroyed. Once the ponds are constructed, the trail on the north side of the driveway will be reconstructed to go around the new pond. Once this is completed, construction will halt for the winter.

Second Year

The following spring, the ponds will fill up with runoff water from the melting snow. Since the ponds are near the river, much of the surrounding area will drain off in the direction of the ponds. During this summer we will construct fences to surround the entire management area, and the entire prairie. This will be absolutely necessary to prevent the turtles from "wandering," says John Moriarty, coauthor of the book, Reptiles and Amphibians in Minnesota (Moriarty Interview 1997).  The necessary area to successfully keep Blanding's turtles from wandering is one square mile (unfortunately, we found this fact out too late to change our specie or our management area - thus, we designed the project to be educational-based with a fence around the entire perimeter).  The fence will be a three foot chain link fence, with six inches underground to prevent the turtles from digging underneath.  At the entrances to the  walking trails, we will have gates. The purpose of the fences is we will prevent the turtles from crossing the driveway and the highway and becoming road kill. We will also build properly designed underpasses under the highway to connect the wetland to the prairie.  These underpasses must be wide enough so that the turtles are not discouraged from crossing through because of a dark, closed, and confined space (Moriarty Interview 1997). The Blanding's turtle needs grasslands 6 hectares in size or larger to nest in (Dorff 1995), so we must have that vital connection to the prairie on the other side of the highway.

Because these ponds are isolated, the time it would take for pioneer aquatic plants to become established would be quite a few years (more years than the six-year plan of this presentation). Therefore, the plants will have to be hand planted. The best time to do this is in the late summer when low water levels expose suitable sites (Payne 1992).  Volunteers at the nature center will help in the planting of sedge grasses, smartweed, and other common wetland vegetation.  The Blanding's turtles prefer a south-facing slope with no vegetation (Representative Species), so when the vegetation is being planted the north side of the pond will be left unvegetated.

Permits will have to be obtained from the Minnesota Section of Ecological Services to possess and transport the Blanding's turtles.  We will also have to obtain permits from the Minnesota DNR Section of Fisheries to release frogs or tadpoles into the ponds (Hall Interview 1997).   As many adult  Blanding's turtles as possible will be obtained from the second year through the fifth year (and beyond, if more turtles are needed) by being on the list of Sites for Confiscated and Wayward Turtles.  This Minnesota organization takes in all species of turtles that are brought into the state illegally or are found in a inhospitable place (such as backyards and schoolyards) and finds new homes for them (zoos, nature centers, etc.) (Moriarty Interview 1997).

Third and Fourth Year

For the next couple of years the area will be monitored and maintained.  These two years will allow the wetland and vegetation to become established.  The Banding's turtles prefer wetlands with 15 - 40 % open water, so the vegetation  must be allowed to grow and occupy much of the water before the turtles can be introduced (Dorff 1995).   During this time, other organisms will begin to occupy the area.  The Blanding's turtle feeds on minnows, tadpoles, crustaceans, insects, and other aquatic life in water.  Eggs from many of these species will be brought into the area by migrating birds (Bergland Interview 1997). Other eggs, such as those from frogs, could be collected from the river edge by volunteers and brought into the area.

In the spring of the fourth year, breeding of the Blanding's turtles will be attempted at the Carpenter Nature Center, both with the turtles acquired from the Sites for Confiscated and Wayward Turtles organization and with the two Blanding's turtles presently living at the CNC.  A Headstart program will be maintained by feeding the hatchlings an accelerated growth diet.  

Fifth Year

During the fifth year, the wetlands will still be maintained and monitored, dredging if necessary to avoid an overgrowth of vegetation.

In the spring, twenty Northern Leopard Frogs will be bought from the Carolina Biological Supply Company (or a similar company) and introduced into the wetland area.

Educational programs on the Blanding's turtles, the leopard frogs, and their ecological environment will be designed. 

Sixth Year

In the spring, the Blanding's turtle adults and hatchlings will be introduced to the new habitat.  Close monitoring of the females during the period when they lay their eggs will be done by volunteers; Blanding's turtles lay their eggs around 9 p.m. at night (Moriarty Interview 1997).  When a nest is discovered, it will be immediately be covered by a screen box to protect it from predators (see past management practices).  During hatching time, the nests will be checked once a day. The nest boxes will be removed when the turtles have hatched. 

Following Years

Close monitoring of both the Blanding's turtles and the leopard frogs will be continued by the volunteers and interns of the Carpenter Nature Center.  Ponds will be dredged if sediment buildup or vegetation overgrowth occurs (which is not very likely).   

Work Allotment

Much of the labor directly relating to the wildlife will be done by volunteers and interns for the Carpenter Nature Center, so much money will be saved and put to different uses.

B.  Budget covered by the Department of Transportation

Description                                       Unit Price           Units                   Debit

*Bulldozer and Crew                                                      $100/hour                16 hours                    $11,000

Clay Blanket and Gravel                                              $500/hectare             6 hectares                           $3,000

Hauling of Organic Material                                 $100/hour                 5 hours                         $500

Sedge grass, smartweed, etc.                                $24/acre                  5 acres                           $70

Other labor                                                           $20/hour                25 hours                        $500

TOTAL:             $15,070

*Data provided by Halvorson Lecture, October 1997.

C.  Remaining Budget

Description                         Unit Price                        Units                    Debit

Leopard frogs                                        $20/frog                                20 frogs                         $400

Food for captive breeding turtles               $150/year                                         3 years                          $450

Permits                                                   $250/each                            2 permits                        $500

Screens and wood for nest boxes           $15/box                                10 boxes                        $150

Road underpasses                                  $500/each                           3 underpasses               $1,500  

Fence                                                                        $5/foot                                           many feet                   ~ $10,000

TOTAL:      $13,000

D.  Twenty Year Management  (not including initial 5 years)

Description                               Unit Price                   Units                  Debit

*Dredging of ponds (doubtful if needed)    $120/hour                          8 hours                         $960 

Repairs (nest boxes, fence)                             ---                                 ---                                $500

TOTAL:           $1,460

GRAND TOTAL:  $29,530

*Data provided by Halvorson Lecture, October 1997.

If the Blanding's turtle and Northern Leopard Frog project was given unlimited funds, many alterations of the proposed project would be made. First, the management area would be made into an unbroken habitat. Highway 21 would be rerouted to go around the Carpenter Nature Center property instead of through it. Currently, the speed limit is 55 mph, but the new private road would have a speed limit of 25 mph or less. The fences surrounding the old highway would be removed to provide a more aesthetically pleasing view to visitors, and turtle crossing signs would be placed up along the road. A wood fence would replace the chain-link fence so it is more pleasing to the eye.  We would attempt to purchase more surrounding land to increase the habitat area. Also, more ponds and marshes would be created throughout the upland prairie area.

Extensive research will be conducted on the Blanding's turtles to obtain more information on the species since there is still much that is not known about the specie. Because of the current and local (Twin Cities) problem of mutations found in the Northern Leopard Frog, special research will be conducted on this specie also.   The research could include statistical analysis of the number of leopard frogs that develop abnormalities due to excess UV radiation and other environmental factors (listed in species life history section) caused by humans.

Using the media, we would make our project high-profile through the local media (newspapers, television news, etc). This will educate people about the two threatened species and what they can do to reduce creating such detrimental factors. Being high-profile, the project will also provide the nature center with needed publicity (moving the road would create less visitors to the CNC because it would no longer be on a county highway). This would increase their yearly attendance and budget. Naturalists would be hired to make the wetland habitat an exceptional education program (for school field trips and for everyday visitors).  The programs would not only include the threatened species, but other wildlife and the ecology of the area.  Decimating and welfare factors, how many of them are related to humans, and what people can do to  help prevent them would also be a big part of the educational programs.

Not only will this habitat be suitable for the Blanding's turtle, but it will provide homes and rest stops to many different species. Because the Blanding's turtle is being threatened by habitat loss, this is one way in which we can help to restore its populations. In this area, we will be able to establish a population of roughly 50 - 60 turtles, 8.8 - 10 turtles per Hectare (Ernst 1994). Not only will this project benefit various wild species, it will also benefit the public. At this time, Carpenter Nature Center has many types of habitats including Apple orchards, oak savanna bluff lands, restored prairie, red pine plantation, fern and moss covered limestone rock outcroppings, two major ravines blanketed in white pine and deciduous vegetation, sandy floodplain peninsula and river frontage on the St. Croix. The one main area it is missing is wetlands. With the construction of wetlands on their land, new programs can be made and used. By doing this, the public will learn about the importance of wetlands and the species that occupy them.  Programs can also be designed to inform the public about threatened and endangered species, and what we can do to help restore the populations, or what we can do to prevent animals from becoming threatened or endangered.

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More Details on Blanding's Turtles in Nova Scotia. http://www.ednet.ns.ca/educ/museum/mnh/nature/turtles/bland.htm 

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     http://www.cciw.ca/eman-temp/reports/newsletters/kejimkujik/blanding_turtle.html

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Petit, Charles.  1992.  "Disappearance of Toads, Frogs Has Some Scientists Worried."    

      http://www.afternet.com/~teal/frogsdecline.html 

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       http://www.cciw.ca/glimr/data/habitat-rehabilitation/hab41a.html

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