Durango Nature Studies Data Summary
Introduction
In Southwest Colorado, approximately twenty miles south of Durango, lies a nature education center that is spread over 140 acres of spacious, mountainous land. Durango Nature Studies (DNS) provides educational services about the nature of the area to over 6,500 people every year. Throughout the 140 acres lie a variety of habitats including ponds, the Florida River, desert-like hills and plains, and meadows.
Currently in Colorado, the Rana catesbeiana, more commonly known as the bullfrog, is a threat to other organisms because bullfrogs are invasive. An invasive species is a species that is not native to the area that they have inhabited and out-compete other species for resources. A bullfrog is just one example of an invasive species. Russian Olive trees, Multifloral Roses, and the Northern Pike fish are just a few other invasive species in Colorado. Invasive species out-compete native species for resources such as habitat and prey, which causes the native species to begin to die. Due to the overpopulation of bullfrogs in Colorado, anyone with a fishing license is allowed to hunt, kill, and take unlimited quantities of bullfrogs.
The bullfrogs and the bluegill fish, which are both invasive species that inhabit the DNS pond, each complete a task to reduce the amount of leopard frogs in the ecosystem. The bullfrogs overthrow the northern leopard frogs, or the Rana pipiens, from covered habitats, forcing the leopard frogs to be exposed in the open water where the bluegills then eat them. This combination of non-native predators puts the population of leopard frogs on the DNS property at risk for eradication.
Natural History
Rana catesbeiana
Bullfrogs, which are typically green with brown spots, are found in freshwater lakes, ponds and marshes all across the U.S., Canada, Cuba, Mexico, and even in sections of Europe, Asia, and South America. Bullfrogs are willing to eat anything that will fit in their mouths, including snakes and birds. Like most frogs, having a habitat with tall grass is a necessity for the bullfrog. The lengthy grass supplies them with a place to hide from predators such as raccoons, owls, and birds. Bullfrogs become inactive when the temperature drops below 59 degrees Fahrenheit. An adult female bullfrog lays an average of 20,000 eggs at one time, requiring a large body of water to house the eggs: the egg is the first stage of life for the bullfrog. If not eaten, the eggs will hatch and tadpoles will emerge. After about one year, the tadpoles will grow arms and legs and one to two years after the limbs appear, the tadpoles will have completed their metamorphosis to a mature frog. On average, bullfrogs live for seven to nine years total.
Rana Pipiens
The northern leopard frog was once the most commonly found frog species in North America, but as invasive species began overtaking their habitats, the northern leopard frog’s population decreased. Now, the northern leopard frog can be found in numerous states in the United States such as Colorado and New Hampshire. Northern leopard frogs are also found in Canada. As the name implies, the northern leopard frog’s green-brown back is covered in dark chaotic spots. Like the bullfrogs, northern leopard frogs eat virtually anything that can fit in their mouths including smaller frogs (even of their own species), garter snakes, and beetles. Northern leopard frogs tend to live near ponds, marshes, or covered grasslands. The metamorphosis of a northern leopard frog is three stages: the first stage of metamorphosis is the egg stage. In the second stage, the egg hatches, and tadpoles are born into the ecosystem. While in the tadpole stage, tadpoles require a pool of water that can be heated by the sun, but deep enough for the water to stay in the pool for the entire larvae stage. Like a bullfrog, the third stage is when the northern leopard frog then morphs into a mature frog over the span of one or two years. During the winter, northern leopard frogs hibernate in mud, in order to avoid water that will freeze entirely.
Materials And Methods
Three techniques were used in order to estimate population size of leopard frogs and bullfrogs on the DNS property; pitfall traps, visual-encounters, and mark-recapture. Two Pitfall traps were set up by both the pond and the Florida River. These five-gallon traps were checked daily. Also, for one-hour periods for four days, visual encounter surveys were conducted around the pond. In addition, one one-hour marking session was conducted. The frogs were marked on the right hind leg so all of the frogs that had already been caught would visually differ from frogs that hadn’t been caught.
At the pond and at the Florida River, water chemistry tests were conducted to measure the levels of nitrates, phosphates, pH, dissolved oxygen, temperature, and coli form. Vegetation Plot Surveys were conducted at four random spots around the boundaries of Durango Nature Studies. Using the kick method, macro invertebrates were collected in the river, and macro invertebrates were collected at the pond using a dip net. These data allowed for assessment of overall ecosystem health.
Results
The data showed the results of the water chemistry tests that were conducted at DNS. The pH level in the pond was ten, which is qualified as alkaline. The pH level of the Florida River was eight, which is also qualified as alkaline. In the pond, the nitrate levels were at six ppms, while the levels of the Florida River were at ten ppms. Both of these bodies of water were identified as having high nitrate levels. The phosphate levels of both the pond and the Florida River were four ppms. This measure is very high for the phosphates. In the Florida River, the dissolved oxygen level was at three ppms, which is a normal level for dissolved oxygen. On the other hand, the levels of dissolved oxygen in the pond were low, with only a mere one ppm. When the pond and the Florida River were tested for coliform, both bodies of water returned positive
In 2011, in the DNS pond 102 macro invertebrates were found, and the biodiversity was 0.99. In 2012, the diversity of the DNS Pond, in which 203 macro invertebrates were found, was 1.03. In 2011, twenty macro invertebrates were found in the Florida River with a diversity index of 1.21. On the other hand, in 2012 364 macro invertebrates were found in the Florida River and the diversity index was 0.88. A significant observation is that zero stoneflies were found in either body of water either year.
The estimated population of the bullfrog at the DNS pond was one bullfrog. There were fifteen northern leopard frogs found in the DNS pond.
Conclusion And Discussion
Through this data collection, it can be theorized that the bullfrog population is decreasing, allowing the leopard frog population to grow. A species cannot be invasive if a significant population of the species doesn’t exist in the ecosystem. The ratio of leopard frogs to bullfrogs in the DNS pond is 15:1 indicating that if the leopard frog was ever a species of concern on the DNS property, they are recovering. This also classifies the bullfrog as not being invasive on the DNS property in Southwest Colorado. The bullfrog is mainly invasive in the west coast of the United States, but originated from the eastern coast of the United States.
The diversity index of the DNS Pond indicated that the ecosystem is functioning, but not extremely stable. Based on the Shannon Wiener Biodiversity Index, the biodiversity of the DNS pond increased 22% of the past year. Despite the impressive increase, the diversity index of 1.21 is still not considered completely stable.
One theory that causes worry about the pond is the level of nitrates and phosphates. The elevated levels of nitrates and phosphates indicated that the pond is at risk of Eutrophication. When a water system goes Eutrophic, there is an overgrowth of algae. This is also called an algal bloom and is caused by high levels of nitrates and phosphates in the water system. Overtime, the alga builds up on the surface of the pond, blocking out the sun and soaking up oxygen. The organisms underneath the layer of algae are deprived of oxygen and suffocate, upsetting the stability of the ecosystem. The DNS pond has elevated phosphate and nitrate levels, leading to the conclusion that even though the Diversity index indicates otherwise, the DNS pond may not be stable and is at risk for an algal bloom.
The water chemistry test for coliform in the pond and in the Florida River also tested positive, indicating that there was fecal matter in the pond at the time. Upstream from this point of the river are many farms with cows. These cows’ fecal matter is being absorbed by soil, which is falling into the river, and flowing throughout the entire river. It is also possible that the coliform originates from other animals on the Durango Nature Studies property that come to the pond. The feces can be washed into the pond by rain and mudslides or by other animals’ feet.
As discussed above, the water quality of the DNS Pond may be putting the pond at risk for algal blooms. The main way to prevent algal blooms is to reduce the amount of nutrients in the body of water. A method called Integrated Catchment Management is being put into action all across Australia. Integrated Catchment Management (ICM) requires many community members to put forth effort to protect the water around them. Simple actions such as planting trees, preventing soil loss, fencing vegetation by water sources, and improving fertilizer management assist in preventing an overflow of phosphate and nitrates in the water, which cause algal blooms.
Implementing the ICM around the Florida River will help to reduce the phosphates and nitrates in the water. If the ICM was enforced on the entire length of the Florida River, it could be possible to reduce the amount of phosphates and nitrates in the water. Farmers upstream from the DNS property could be persuaded to use less fertilizer in order to prevent nitrate and phosphate-contaminated soil from falling in the river. If everyone across the United State implemented the ICM into his or her communities, water everywhere could be more natural and less toxic.
Coliform in water is another problem that can be simply reduced through controlling your animals. If animals are restrained to a certain area, so are their feces. Cows’ boundaries can be adjusted so they are further away from the river, preventing coliform-contaminated soil from entering the water. One uncontrollable way that coliform could be reaching the water sources is through wild animals. For example, if a deer is walking through the woods to the Florida River, it is plausible that that deer will step in feces. Remnants of the feces will most likely stay on that deer’s foot until it reaches the water. There is no plan that can keep these animals from drinking from their nearest water source, but if the domestic animals are kept away from the river, the amount of coliform in the DNS pond can be reduced.
Works Cited
"American Bullfrog - Point Map." American Bullfrog - Point Map. USGS, 10 Oct. 2012. Web. 10 Oct. 2012. <http://nas2.er.usgs.gov/viewer/omap.aspx?SpeciesID=71>.
"American Bullfrog - Point Map." American Bullfrog - Point Map. USGS, 10 Oct. 2012. Web. 10 Oct. 2012. <http://nas2.er.usgs.gov/viewer/omap.aspx?SpeciesID=71>.
"American Bullfrog." National Geographic. National Geographic, n.d. Web. 10 Oct. 2012. <http://animals.nationalgeographic.com/animals/amphibians/american-bullfrog/>.
"Bullfrog Life Cycle." Bullfrog Life Cycle. Bullfrogs.com, n.d. Web. 1 Oct. 2012. <http://www.bullfrogs.com/Bullfrog-Life-Cycle.html>.
"Colorado's Amphibians and Reptiles." Colorado's Amphibians and Reptiles: Species Status, Regulations, Information. Colorado Division of Wildlife, Jan. 2001. Web. <http://wildlife.state.co.us/SiteCollectionDocuments/DOW/RulesRegs/HerpReport.pdf>.
Delach, Aimee. "Invasive Species In Colorado." Invasive Species In Colorado. Defenders Of Wildlife, n.d. Web. <http://www.defenders.org/publications/colorado.pdf>.
"Durango Nature Studies - Environmental Education in Durango, Southwest Colorado, and the Four Corners." Durango Nature Studies - Environmental Education in Durango, Southwest Colorado, and the Four Corners. N.p., 2011. Web. <http://www.durangonaturestudies.org/center1.htm>.
"Google Maps." Google Maps. Google, n.d. Web. 10 Oct. 2012. <https://maps.google.com/maps?hl=en>.
Harding, Jim. "Bullfrog: Rana Catesbeiana." Bullfrog. N.p., n.d. Web. 3 Oct. 2012. <http://www.fcps.edu/islandcreekes/ecology/bullfrog.htm>.
"Invasive Species." SAVE THE FROGS! N.p., 2011. Web. 10 Oct. 2012. <http://www.savethefrogs.com/threats/invasive-species.html>.
"Northern Leopard Frog- Rana Pipiens." New Hampshire Public Television. Wildlife Journal Junior, 2012. Web. 4 Oct. 2012. <http://www.nhptv.org/wild/northernleopardfrog.asp>.
Smith, Brian E., and Doug Keinath. "Habitat Requirements." Species Assessment for the
Northern Leopard Frog (rana Pipiens) in Whyoming (2004): 10-16. Print.
"Water Facts: Water and Rivers Commission July 1998." Water Facts. Government of Western Australia, July 1998. Web. 10 Oct. 2012. <http://www.water.wa.gov.au/PublicationStore/first/10085.pdf>.
In Southwest Colorado, approximately twenty miles south of Durango, lies a nature education center that is spread over 140 acres of spacious, mountainous land. Durango Nature Studies (DNS) provides educational services about the nature of the area to over 6,500 people every year. Throughout the 140 acres lie a variety of habitats including ponds, the Florida River, desert-like hills and plains, and meadows.
Currently in Colorado, the Rana catesbeiana, more commonly known as the bullfrog, is a threat to other organisms because bullfrogs are invasive. An invasive species is a species that is not native to the area that they have inhabited and out-compete other species for resources. A bullfrog is just one example of an invasive species. Russian Olive trees, Multifloral Roses, and the Northern Pike fish are just a few other invasive species in Colorado. Invasive species out-compete native species for resources such as habitat and prey, which causes the native species to begin to die. Due to the overpopulation of bullfrogs in Colorado, anyone with a fishing license is allowed to hunt, kill, and take unlimited quantities of bullfrogs.
The bullfrogs and the bluegill fish, which are both invasive species that inhabit the DNS pond, each complete a task to reduce the amount of leopard frogs in the ecosystem. The bullfrogs overthrow the northern leopard frogs, or the Rana pipiens, from covered habitats, forcing the leopard frogs to be exposed in the open water where the bluegills then eat them. This combination of non-native predators puts the population of leopard frogs on the DNS property at risk for eradication.
Natural History
Rana catesbeiana
Bullfrogs, which are typically green with brown spots, are found in freshwater lakes, ponds and marshes all across the U.S., Canada, Cuba, Mexico, and even in sections of Europe, Asia, and South America. Bullfrogs are willing to eat anything that will fit in their mouths, including snakes and birds. Like most frogs, having a habitat with tall grass is a necessity for the bullfrog. The lengthy grass supplies them with a place to hide from predators such as raccoons, owls, and birds. Bullfrogs become inactive when the temperature drops below 59 degrees Fahrenheit. An adult female bullfrog lays an average of 20,000 eggs at one time, requiring a large body of water to house the eggs: the egg is the first stage of life for the bullfrog. If not eaten, the eggs will hatch and tadpoles will emerge. After about one year, the tadpoles will grow arms and legs and one to two years after the limbs appear, the tadpoles will have completed their metamorphosis to a mature frog. On average, bullfrogs live for seven to nine years total.
Rana Pipiens
The northern leopard frog was once the most commonly found frog species in North America, but as invasive species began overtaking their habitats, the northern leopard frog’s population decreased. Now, the northern leopard frog can be found in numerous states in the United States such as Colorado and New Hampshire. Northern leopard frogs are also found in Canada. As the name implies, the northern leopard frog’s green-brown back is covered in dark chaotic spots. Like the bullfrogs, northern leopard frogs eat virtually anything that can fit in their mouths including smaller frogs (even of their own species), garter snakes, and beetles. Northern leopard frogs tend to live near ponds, marshes, or covered grasslands. The metamorphosis of a northern leopard frog is three stages: the first stage of metamorphosis is the egg stage. In the second stage, the egg hatches, and tadpoles are born into the ecosystem. While in the tadpole stage, tadpoles require a pool of water that can be heated by the sun, but deep enough for the water to stay in the pool for the entire larvae stage. Like a bullfrog, the third stage is when the northern leopard frog then morphs into a mature frog over the span of one or two years. During the winter, northern leopard frogs hibernate in mud, in order to avoid water that will freeze entirely.
Materials And Methods
Three techniques were used in order to estimate population size of leopard frogs and bullfrogs on the DNS property; pitfall traps, visual-encounters, and mark-recapture. Two Pitfall traps were set up by both the pond and the Florida River. These five-gallon traps were checked daily. Also, for one-hour periods for four days, visual encounter surveys were conducted around the pond. In addition, one one-hour marking session was conducted. The frogs were marked on the right hind leg so all of the frogs that had already been caught would visually differ from frogs that hadn’t been caught.
At the pond and at the Florida River, water chemistry tests were conducted to measure the levels of nitrates, phosphates, pH, dissolved oxygen, temperature, and coli form. Vegetation Plot Surveys were conducted at four random spots around the boundaries of Durango Nature Studies. Using the kick method, macro invertebrates were collected in the river, and macro invertebrates were collected at the pond using a dip net. These data allowed for assessment of overall ecosystem health.
Results
The data showed the results of the water chemistry tests that were conducted at DNS. The pH level in the pond was ten, which is qualified as alkaline. The pH level of the Florida River was eight, which is also qualified as alkaline. In the pond, the nitrate levels were at six ppms, while the levels of the Florida River were at ten ppms. Both of these bodies of water were identified as having high nitrate levels. The phosphate levels of both the pond and the Florida River were four ppms. This measure is very high for the phosphates. In the Florida River, the dissolved oxygen level was at three ppms, which is a normal level for dissolved oxygen. On the other hand, the levels of dissolved oxygen in the pond were low, with only a mere one ppm. When the pond and the Florida River were tested for coliform, both bodies of water returned positive
In 2011, in the DNS pond 102 macro invertebrates were found, and the biodiversity was 0.99. In 2012, the diversity of the DNS Pond, in which 203 macro invertebrates were found, was 1.03. In 2011, twenty macro invertebrates were found in the Florida River with a diversity index of 1.21. On the other hand, in 2012 364 macro invertebrates were found in the Florida River and the diversity index was 0.88. A significant observation is that zero stoneflies were found in either body of water either year.
The estimated population of the bullfrog at the DNS pond was one bullfrog. There were fifteen northern leopard frogs found in the DNS pond.
Conclusion And Discussion
Through this data collection, it can be theorized that the bullfrog population is decreasing, allowing the leopard frog population to grow. A species cannot be invasive if a significant population of the species doesn’t exist in the ecosystem. The ratio of leopard frogs to bullfrogs in the DNS pond is 15:1 indicating that if the leopard frog was ever a species of concern on the DNS property, they are recovering. This also classifies the bullfrog as not being invasive on the DNS property in Southwest Colorado. The bullfrog is mainly invasive in the west coast of the United States, but originated from the eastern coast of the United States.
The diversity index of the DNS Pond indicated that the ecosystem is functioning, but not extremely stable. Based on the Shannon Wiener Biodiversity Index, the biodiversity of the DNS pond increased 22% of the past year. Despite the impressive increase, the diversity index of 1.21 is still not considered completely stable.
One theory that causes worry about the pond is the level of nitrates and phosphates. The elevated levels of nitrates and phosphates indicated that the pond is at risk of Eutrophication. When a water system goes Eutrophic, there is an overgrowth of algae. This is also called an algal bloom and is caused by high levels of nitrates and phosphates in the water system. Overtime, the alga builds up on the surface of the pond, blocking out the sun and soaking up oxygen. The organisms underneath the layer of algae are deprived of oxygen and suffocate, upsetting the stability of the ecosystem. The DNS pond has elevated phosphate and nitrate levels, leading to the conclusion that even though the Diversity index indicates otherwise, the DNS pond may not be stable and is at risk for an algal bloom.
The water chemistry test for coliform in the pond and in the Florida River also tested positive, indicating that there was fecal matter in the pond at the time. Upstream from this point of the river are many farms with cows. These cows’ fecal matter is being absorbed by soil, which is falling into the river, and flowing throughout the entire river. It is also possible that the coliform originates from other animals on the Durango Nature Studies property that come to the pond. The feces can be washed into the pond by rain and mudslides or by other animals’ feet.
As discussed above, the water quality of the DNS Pond may be putting the pond at risk for algal blooms. The main way to prevent algal blooms is to reduce the amount of nutrients in the body of water. A method called Integrated Catchment Management is being put into action all across Australia. Integrated Catchment Management (ICM) requires many community members to put forth effort to protect the water around them. Simple actions such as planting trees, preventing soil loss, fencing vegetation by water sources, and improving fertilizer management assist in preventing an overflow of phosphate and nitrates in the water, which cause algal blooms.
Implementing the ICM around the Florida River will help to reduce the phosphates and nitrates in the water. If the ICM was enforced on the entire length of the Florida River, it could be possible to reduce the amount of phosphates and nitrates in the water. Farmers upstream from the DNS property could be persuaded to use less fertilizer in order to prevent nitrate and phosphate-contaminated soil from falling in the river. If everyone across the United State implemented the ICM into his or her communities, water everywhere could be more natural and less toxic.
Coliform in water is another problem that can be simply reduced through controlling your animals. If animals are restrained to a certain area, so are their feces. Cows’ boundaries can be adjusted so they are further away from the river, preventing coliform-contaminated soil from entering the water. One uncontrollable way that coliform could be reaching the water sources is through wild animals. For example, if a deer is walking through the woods to the Florida River, it is plausible that that deer will step in feces. Remnants of the feces will most likely stay on that deer’s foot until it reaches the water. There is no plan that can keep these animals from drinking from their nearest water source, but if the domestic animals are kept away from the river, the amount of coliform in the DNS pond can be reduced.
Works Cited
"American Bullfrog - Point Map." American Bullfrog - Point Map. USGS, 10 Oct. 2012. Web. 10 Oct. 2012. <http://nas2.er.usgs.gov/viewer/omap.aspx?SpeciesID=71>.
"American Bullfrog - Point Map." American Bullfrog - Point Map. USGS, 10 Oct. 2012. Web. 10 Oct. 2012. <http://nas2.er.usgs.gov/viewer/omap.aspx?SpeciesID=71>.
"American Bullfrog." National Geographic. National Geographic, n.d. Web. 10 Oct. 2012. <http://animals.nationalgeographic.com/animals/amphibians/american-bullfrog/>.
"Bullfrog Life Cycle." Bullfrog Life Cycle. Bullfrogs.com, n.d. Web. 1 Oct. 2012. <http://www.bullfrogs.com/Bullfrog-Life-Cycle.html>.
"Colorado's Amphibians and Reptiles." Colorado's Amphibians and Reptiles: Species Status, Regulations, Information. Colorado Division of Wildlife, Jan. 2001. Web. <http://wildlife.state.co.us/SiteCollectionDocuments/DOW/RulesRegs/HerpReport.pdf>.
Delach, Aimee. "Invasive Species In Colorado." Invasive Species In Colorado. Defenders Of Wildlife, n.d. Web. <http://www.defenders.org/publications/colorado.pdf>.
"Durango Nature Studies - Environmental Education in Durango, Southwest Colorado, and the Four Corners." Durango Nature Studies - Environmental Education in Durango, Southwest Colorado, and the Four Corners. N.p., 2011. Web. <http://www.durangonaturestudies.org/center1.htm>.
"Google Maps." Google Maps. Google, n.d. Web. 10 Oct. 2012. <https://maps.google.com/maps?hl=en>.
Harding, Jim. "Bullfrog: Rana Catesbeiana." Bullfrog. N.p., n.d. Web. 3 Oct. 2012. <http://www.fcps.edu/islandcreekes/ecology/bullfrog.htm>.
"Invasive Species." SAVE THE FROGS! N.p., 2011. Web. 10 Oct. 2012. <http://www.savethefrogs.com/threats/invasive-species.html>.
"Northern Leopard Frog- Rana Pipiens." New Hampshire Public Television. Wildlife Journal Junior, 2012. Web. 4 Oct. 2012. <http://www.nhptv.org/wild/northernleopardfrog.asp>.
Smith, Brian E., and Doug Keinath. "Habitat Requirements." Species Assessment for the
Northern Leopard Frog (rana Pipiens) in Whyoming (2004): 10-16. Print.
"Water Facts: Water and Rivers Commission July 1998." Water Facts. Government of Western Australia, July 1998. Web. 10 Oct. 2012. <http://www.water.wa.gov.au/PublicationStore/first/10085.pdf>.