Biology Semester 1 project
Species Management Plan for Rana pipiens & Rana catesbiena on the Durango Nature Studies Nature Center Property
Josh Giersch and Grayson Mooney
Durango, CO
2011
Field Condition Form Josh Giersch
Durango Nature Studies nature center has a native population of Leopard frogs on the property and needs a plan to manage the frog’s habitat due to the high danger Bull Frogs act to the Leopard Frog habitat. According to Smith (2004) Bullfrogs have eaten off other native amphibian’s food at times killing off that species in the past around the USA. Since DNS is a non-profit organization protecting habitats part of the ecosystem at the DNS property, the leopard frog habitat stays a top priority due to the danger Bullfrogs face to the leopard frog habitat. According to Smith (2004), The Northern Leopard Frog lives with many other amphibians on the DNS property ranging from flies to crawdads. Animas High biology will take the opportunity to establish a plan to preserve a stable population for the Leopard Frog habitat. Working locally also establishes more knowledge on other ecosystems in South West Colorado. Animas High biology has visited the leopard frog habitat recording data on other habitats near the leopard frog habitat. Animas biology also tested the water quality of the leopard frog habitat to identify the waters health (figure 3). Having been to the pond also allows a better understanding of the habitats current condition. According to Durangonaturestudies.org (2010) DNS property has 105 acres of protected land home to animals ranging from mountains lions and frogs (figure 1). Many local schools visit the DNS property on nature trips or tour groups taking nature hikes. DNS is a non-profit organization protecting the properties habitats so visitors may enjoy the property. The DNS property has set aside 2,000 dollars for maintaining the leopard frog habitat by using materials to keep a stable population of frogs on the property for the future. The money will also be used for regular monitoring and ongoing management (figure 6).
Plan Development Josh G
Leopard frogs are a frog species native to the USA well known for sensitivity to chemical pollutants found in water and air. According to (Smith, 2004) Leopard frog habitats are located in ponds and lakes where the tadpoles are raised until the leopard frogs are self-dependant. Breeding ponds ideally do not contain fish but always require an open canopy. A study found that leopard frogs tend to breed in quiet and shallow parts of water and in seasonally flooded areas that are adjacent with streams in Colorado. Tadpoles also require water free of predaceous fish. Overwintering mortality is an important cause of mortality for leopard frogs when the frogs may hibernate under water in ponds. A source of overwintering mortality may be oxygen depletion which could account for overwintering at inflow areas where oxygen saturation of water is high. Pond spacing, landscape patterns and frog movement are important factors to consider when managing leopard frogs. A bullfrog habitat can be found in vegetation along large bodies of slow moving water where there are plenty of insects to eat (yarnell, 1999). Bullfrogs can lay up to 25,000 eggs at a time. Bullfrogs can be in the tadpole stage for up to two years at a time (keeping bullfrogs in a stable habitat will keep a stable population for the future). As most amphibians eat insects, bullfrogs have been known for their aggressive predation of native frog species destruction to other native frog species which out competes the majority of food other frogs rely on. Durango Nature Studies has a variety of habitats on the 142 acre property, making DNS one large ecosystem (figure 1). The Florida River runs through the area into multiple ponds that are home to other amphibians such as the northern leopard frog. Animas High School research estimates the leopard frog population to be over 10 frogs along with an estimated over 2 bull frogs living on the property (figure 2). With a nitrate level of 1ppm, this means the pond and river is unpolluted. The PH of the pond and river is about 8 which are considered alkaline, a normal level. The dissolved oxygen of the water was between 6.5 to 8.5 mg/l which is healthy (figures 3 and 4). The phosphate levels were 1ppm for the pond and 4ppm for the River which means the phosphate levels are high meaning the water is polluted. The DNS frog habitats water overall is normal.
Plan Implementation Grayson Mooney
Bullfrogs can be managed in a number of ways. There are swim and trip fall traps [1], fluorescent dye that is inserted under the skin to mark the frog [2], and of course, lethal measures. Swim traps are placed in the water, near or in aquatic plants where frogs hide from predators. The swim traps close around the frog when they run into it, and then is easily collected afterwards, to relocate the frog to a place where it is native, or to kill it on the spot. Pitfall traps work much the same way, except they are placed on land, not in the water. These traps catch invasive frogs and are effective because if a trap catches a native frog, the frog can easily be turned loose and the trap reset. They are also completely non-lethal and do not cause harm to the frogs that they catch. Once the traps have caught a number of Bullfrogs, then they are transported to an area that they are native to and released. This avoids the trouble of killing the frogs and can help avoid heartbreak. One thing that can be used alongside the traps is a fluorescent dye that is injected under a captured frog's skin to make them easily visible to researchers attempting to count the number of bullfrogs in an area. The dye is also non-lethal and does not harm the frog unless incorrectly injected. If these do not work, then lethal methods may be necessary. These include shooting, clubbing, spearing, and destroying bullfrog eggs [3]. Collecting eggs is most effective because it is quick, easy, and effectively reduces bullfrog populations with little effort exerted by the exterminators. Bullfrog eggs can be identified by their round black centers and larger size than native frog eggs [4]. The most effective way to dispose of said eggs to destroy them with fire [5]. This ensures that an entire population of bullfrogs will not be unleashed upon the habitat that is being protected.
The extermination effort will take place predominantly during the spring and summer because that is when the bullfrogs are breeding and putting out eggs [6]. During breeding season, which lasts from late spring to early summer, traps will be laid out and the frogs captured will be placed in a cooler and gassed to death with Co2. This will not stop the bullfrogs entirely, but does cut down breeding pairs. Once eggs are released they shall be collected with fine mesh nets and destroyed with fire [7]. Those collecting eggs will have to work fast because bullfrog eggs hatch within three to five days of being put out [8]. Once the bullfrog eggs have hatched, then efforts will be made to catch the tadpoles as well. These too will be destroyed with fire. Efforts to exterminate bullfrog populations will not cease during the fall and winter either. Bullfrogs hibernate by burying themselves in the mud of the banks of whatever body of water they live in [9]. They can be dug up with spades and either transported back to areas where they are native, or killed on the spot, either by gassing them or killing them by hand. If you repeat this plan, then within four years bullfrog populations within the habitat that is being protected will be completely exterminated.
Budgeting is also important (figure 6). For this project there is a total budget of two thousand dollars, so it is paramount for the project to be cheap and very effective. To begin, everything that the project will need must be relatively cheap and able to carry out the project for months if not years on a minimal budget. Traps come first, because they are the first element of the project. An average industrial grade frog trap costs twelve dollars including shipping and handling, a very good deal, and only a drop out of the bucket in terms of budget [10]. After traps are nets to catch adult bullfrogs and collect their eggs. A typical ten inch fine mesh net costs only three dollars, meaning that any number of them can be purchased for a minimal price [11]. A five pound tank of Co2 for gassing captured frogs is more expensive, but not unmanageable,
Plan Evaluation Josh Giersch
Bullfrogs face a serious threat to the safety of the Leopard frog habitat over at Durango Nature Studies property. A plan to keep the Leopard frog habitat stable for the future has been created. The plan would have a variety of effects on the habitat eventually reducing the bullfrog population which decreases danger to the Leopard frog habitat. Animas High Biology results show had two Bullfrog sightings and eleven Leopard Frog sightings based on data gathered at the DNS frog pond from past field work Animas biology has done (figure 2. The plan would kill off the entire Bullfrog population over a period of six years. Keeping in mind a bullfrog can have up to twenty thousand eggs at a time; the plan would remove all current eggs and prevent more bull frog eggs from being laid in the future. (Keinath, Habitat Requirements). The plan laid out would reduce the danger Bullfrogs pose to Leopard Frogs considering the smaller the Bullfrog population the less danger the Leopard Frog habitat faces. The plan created would take place over six years with the current $2,000 budget (figure 6) given eventually leading to the destruction of the entire Bullfrog population. When the plan is put into place, the habitat would be monitored the first year every month and eventually after the first year, continuous monitoring would happen every three months. Data would be recorded each time from the continuous monitoring over a period of six years. When the six year plan is put into place, the data recorded would be evaluated to make sure a decrease in the bull frog population stands out in the data. Assuming the $2,000 dollar budget stays the same, the timeline for the plan would take place over six years. The current laid out plans objectives would be met after six years when the budget would be used up and the plans objective of decreasing the Bullfrog population would also be met.
Figure 1
Figure 2
Water Quality Data: Pond
| POND | Our Results | Is It Polluted? |
| pH | 8-9 | No |
| Nitrates | 1ppm | No |
| Phosphates | 1ppm | No |
| Dissolved Oxygen | 6.5-8.5mg/L | No |
| Coliform | Positive | No |
Figure 3
Water Quality Data: Florida River
| FLORIDA RIVER Data | Our Results | Is It Polluted? |
| pH | 8-9 | No |
| Nitrates | 2ppm | No |
| Phosphates | 4ppm | Yes |
| Dissolved Oxygen | 6.5-8.5mg/L | No |
| Coliform | Positive | No |
Figure 4
Macroinvertebrate Data: Pond and River
| Damsel | 53 | 0.34 | Caddis | 120 | 0.36 | ||
| Mayfly | 41 | 0.37 | Mayfly | 125 | 0.36 | ||
| Midge | 5 | 0.15 | Midge | 15 | 0.16 | ||
| Caddis | 2 | 0.08 | Blackfly | 5 | 0.07 | ||
| Dragon | 1 | 0.04 | Coleoptera | 5 | 0.07 | ||
| Black | 0 | 0 | Stone | 0 | 0 | ||
| Coleoptera | 0 | 0 | Damsel | 0 | 0 | ||
| Stone | 0 | 0 | Dragon | 0 | 0 | ||
| DNS pond | Florida River | ||||||
| Biodiversity: 102 | Biodiversity: 270 | ||||||
| Shannon Weiner: 0.98 | Shannon Weiner: 1.02 | ||||||
Figure 5
| Item | Quantity | Cost |
| Pitfall Traps | Ten | $120 |
| Nets | Ten | $30 |
| Co2 Tank | One | $50 |
| Collapsible Shovels | Ten | $60 |
| Cooler | One | $16 |
| Total Cost: $276 |
Figure 6
Reference List
"5lbs Co2 Tank." eBay. N.p., 13 Sept. 2011. Web. 12 Oct. 2011.
"10'' Mesh Butterfly and Fish Net." eBay. N.p., 18 Aug. 2011. Web. 12 Oct. 2011.
"1904 Orvis Flint Glass Minnow and Frog trap ." eBay. N.p., 13 July 2011. Web. 12 Oct. 2011.
"Gerber Legendary Blades 22-41578 Gorge Folding Shovel." Google Product Search. N.p., 15 June 2010. Web. 12 Oct. 2011.
"Igloo Island Breeze 28 Quart Cooler." Walmart.com. N.p., 21 Aug. 2011. Web. 12 Oct. 2011.
Bullfrog Control. N.p.: n.p., 2008. 1. Web. 12 Oct. 2011.
Bullfrog Rana catesbeiana." All about frogs. allaboutfrogs.org, 2010. Google. Web. 12 Oct. 2011. <http://allaboutfrogs.org/info/species/bullfrog.html>.
Bullfrogs. N.p.: Wikipedia, 2005. 1. Web. 12 Oct. 2011.
Emmer, Rick. How do Frogs Survive The Winter. Vol. 1. Cleveland: Cleveland City Zoo, 1997. 1. 1 vols. Web.
Fishpond Egg Identification. N.p.: n.p., 2002. 1. Web. 12 Oct. 2011.
Graham, Donna. NORTHERN LEOPARD FROG. Northern.edu, 1997. Google. Web. 10 Oct. 2011. <http://www3.northern.edu/natsource/AMPHIB1/Northe1.htm>.
Hoffman, Kristine, Monica McGarrity, and Steve Johnson. Technology Meets Tradition: A Combined VIE-C Technique for Individually Marking Anurans. Miami: University of Florida, 2005. 1. Web. 12 Oct. 2011.
Pitfall Traps. N.p.: Wikipedia, 2011. 1. Web. 12 Oct. 2011.
Shapiro, Lisa. Pond Water and Pollywogs. Intel Education, 2008. Web. 4 Oct. 2011. <http://www97.intel.com/en/ProjectDesign/UnitPlanIndex/PondwaterAndPollywogs/>.
Smith, Brian E., and Doug Keinath. "Habitat Requirements." Species Assesment for The Northern Leopard Frog 1 Jan. (2004): 1-89. Print.
Yarnell, S. Sierra Nevada Ecosystems. N.p., 1996. Web. 4 Oct. 2011. <http://www.fs.fed.us/psw/topics/ecosystem_processes/sierra/bio_diversity/aquatic_anthropogenic_sub1/pulse_flow_effects.shtml>.
For the species management project, we studied the threatened species the Leopard Frog habitat over at Durango Nature Studies Property and did water tests to identify the current condition of the water and other threats facing leopard frogs such as the bull frog and came up with a plan to create a stable leopard frog habitat for under $2,000. We also created a PowerPoint showing the water results, the management plan we created for Durango Nature Studies and had a 12 page plan typed out talking in more details about the data from the water tests and what the results meant and our plan for continued monitoring of the frog habitat. The plan demonstrated the plan on how we would remove the bull frogs and other threats to the leopard frog habitat. The water results also showed the pond is well pollution wise but the only threat from the water tests was the phosphates which was an area of concern since too much of that nutrient can impact amphibian life. The article, “Time to stop worrying about invasive species,” talks about how when people hear the word non-native species that they shouldn’t think all bad things when that species at times might not be a threat to the habitat they are in. An example is where it says: “You shouldn’t judge a book by its cover. And you shouldn’t judge a species by its place of origin.” This article suggests invasive species should be seen not always as a threat when most of the time we think it is, but only judge it by the impact it has on other habitats. This article is a good example of the DNS habitat situation where many just assumed since the bull frog was a non-native species; we should get rid of it without seeing the impacts it does to other habitats. I think bullfrogs should be a concern to other Colorado amphibian habitats considering that the bullfrog is quite a big threat to the leopard frog, other habitats should be checked specifically for bullfrog trouble since these things do happen. I don’t think invasive species are a threat everywhere in the DNS case, the bullfrog isn’t native and happens to be around the leopard frog, but there are other places out there such as Canada where the bullfrog is native and isn’t an issue, so I don’t think invasive species are an issue globally. I think the work I did the last 8 weeks was worthwhile considering I had never done that much research on amphibians or written a management plan, so even if the plan I made isn’t the best one, the knowledge I gained is worthwhile and can be used for the rest of biology and the future. From this project, I learned quite a bit of new things. I learned all about frogs, how to understand water test data and I learned a lot of information just about the local frog habitat here in Durango. I have a better understanding how to write a management plan based on examining data. I learned in ecology about how DNS is one big ecosystem and how the habitats at DNS run naturally. I don’t think my plan will be used in the future considering I didn’t have the best understanding of all the data, but it was a good plan for a first time. I learned to read science reading out of the text book for interpreting the data. I learned to identify other species from research I did and having been to the habitat doing tests a while ago. I have a better understanding now of the invasive species because before I didn’t even know what an invasive species was. I felt more comfortable doing presentations now especially considering I am around a different group of people. I learned math wise how to do Shannon wiener so I can find the biodiversity of a species. I used excel to make some graphs I used in my PowerPoint since before I never had used excel in my life, but now am more comfortable with using the program.
