Amphibian population estimates and ecosystem assessment on the Durango Nature Studies Property
Introduction
Durango Nature Studies (DNS) is a nature preserve located outside Durango, CO near the New Mexico border. Durango Nature Studies aims to educate others about ecology. The DNS property is 140 acres, and has a variety of habitats; meadows, oak woodlands, and desert arroyos. The top Thirty-five acres consist of a prairie dog colony and parking area. There is a footpath that goes down 105 acres bordering the Florida River. Several local organizations use the DNS property for biology-based research including; riparian, meadows, oak woodlands, piñon-juniper forests, and desert arroyos.
In recent years, bullfrogs have been spotted on the DNS property. Bullfrogs are a non-native species that are out-competing leopard frogs for resources, endangering native frog populations, including those in the pond on the DNS property and the Florida River. Bullfrogs are immune to Batrachochyrtrium dendrobatidis, which is considered a main cause for global amphibian decline. This makes the bullfrogs have a much larger population than other amphibians, increasing their ability to survive. Bullfrogs must have water and thick vegetation to survive. Aquatic habitats are healthy for bullfrogs. Very few bullfrogs will be in one body of water. Metamorphosis can take 2 or more years for bullfrogs, and they live, on average, 8-10 years.
Invasive species have become a concern due to them out-competing the native species for food and other necessities for life. This endangers the native species’ and can destroy the species altogether. Bullfrogs are doing this to leopard frogs, and leopard frogs could become extinct due to being out-competed by the bullfrogs.
The bullfrogs and the bluegills both play a part in the decrease in leopard frog populations. The bullfrogs take places to live that are farther away from the side of the river, forcing the leopard frogs to move to the water, making them prey to the bluegills.
The current status of the leopard frogs in Colorado is that the species is becoming endangered. This is mainly due to invasive species, specifically the bullfrog. Leopard frogs have been killed by fertilizers and pesticides that have been put into their environments as well. Grazing animals and droughts have also had a negative effect on leopard frogs due to lack of food and resources to survive. Leopard frogs need to have a nearby water source for reproduction and for survival. Riparian habitats are optimal for leopard frogs as they have water and vegetation. Eggs hatch in 9 or more days, and metamorphosis is completed within 2 months, starting in January and August. Leopard frogs live from one to three years.
Methods & Materials
At the Durango Nature Studies Pond, 4 pitfalls traps were set up and checked daily for frogs that had fallen in overnight. Visual encounter surveys were conducted around the pond for each of the four days. One hour mark sessions and a one hour recapture session was conducted. Water chemistry tests were conducted to record nitrates, phosphates, dissolved oxygen, and pH in the DNS pond and the Florida River. Macroinvertebrates were collected in the river using a kick method as well as a dip net.
Results
The data macroinvertebrate data from 2012 shows there were five damselflies, ten mayflies, two dragonflies, and three riffle beetles in the DNS pond. The overall diversity index was 1.21 using the Shannon-Wiener index. The data showed there were 57 mayflies, 14 midges, 270 caddisflies, 2 dragonflies, 1 blackfly, 11 riffle beetles, and 9 craneflies. The river rated a .88 on the Shannon-Wiener scale. No stoneflies were found in the river, which suggests there is a dangerous level of pollution for stoneflies in the river. Other test taken on the river suggested that both the pond and the river have high phosphate levels, alkaline pH, and high nitrate levels. The pond data suggested that there is low dissolved oxygen, while the river data suggested there are normal levels of dissolved oxygen. Data collected from capture and recapture sessions suggested there is 1 bullfrog and 11 leopard frogs inhabiting the DNS pond.
Conclusion & Discussion
Our data tells us that there is an adequate diversity of macroinvertebrates in the DNS pond, with a diversity of 1.21 on the Shannon-Wiener diversity scale. There is not an adequate amount of diversity in the River, likely due to the overwhelming amount of caddisflies. Not stoneflies were found in the river, suggesting that pollution levels are too high for the organism to survive. Our data also tells us that there is one bullfrog and 11 leopard frogs in the pond. This suggests that there is not a shortage of leopard frogs in the area. We have learned that there is a healthy amount of leopard frogs, and there is no need to worry about populations of leopard frogs due to bullfrogs. The water quality is above average for most of the categories in both the river and the pond, and out data suggests that this could be affecting populations of stoneflies and diversity in the river. I felt as though the process for collecting data was clean and smooth, though catching frogs was a bit difficult because of the speed at which they travel. I do feel as though there was enough time to identify whether or not it was a bullfrog of leopard frog by getting a quick scan of the animal. I feel as though the pond was fine for leopard frogs, as there was only one bullfrog. One bullfrog won’t take up the entire area for good housing, and there is plenty of room for leopard frogs to set up and survive. Phosphates and nitrates are nutrients to keep plants alive. When there are too many phosphates and nitrates, the pond can be at risk of algal bloom. The DNS pond could be at risk of algal bloom, because of high levels of phosphates and nitrates. Normal phosphate levels are .03 ppm, while the pond has levels of 4 ppm. Normal levels of nitrates are 4 ppm, while the river has a nitrate level of 6 ppm. Dangerous levels of nitrates are 40 ppm. The river is at risk of algal bloom, mostly from adequately high levels of phosphates, but is not completely in the danger zone.
Introduction
Durango Nature Studies (DNS) is a nature preserve located outside Durango, CO near the New Mexico border. Durango Nature Studies aims to educate others about ecology. The DNS property is 140 acres, and has a variety of habitats; meadows, oak woodlands, and desert arroyos. The top Thirty-five acres consist of a prairie dog colony and parking area. There is a footpath that goes down 105 acres bordering the Florida River. Several local organizations use the DNS property for biology-based research including; riparian, meadows, oak woodlands, piñon-juniper forests, and desert arroyos.
In recent years, bullfrogs have been spotted on the DNS property. Bullfrogs are a non-native species that are out-competing leopard frogs for resources, endangering native frog populations, including those in the pond on the DNS property and the Florida River. Bullfrogs are immune to Batrachochyrtrium dendrobatidis, which is considered a main cause for global amphibian decline. This makes the bullfrogs have a much larger population than other amphibians, increasing their ability to survive. Bullfrogs must have water and thick vegetation to survive. Aquatic habitats are healthy for bullfrogs. Very few bullfrogs will be in one body of water. Metamorphosis can take 2 or more years for bullfrogs, and they live, on average, 8-10 years.
Invasive species have become a concern due to them out-competing the native species for food and other necessities for life. This endangers the native species’ and can destroy the species altogether. Bullfrogs are doing this to leopard frogs, and leopard frogs could become extinct due to being out-competed by the bullfrogs.
The bullfrogs and the bluegills both play a part in the decrease in leopard frog populations. The bullfrogs take places to live that are farther away from the side of the river, forcing the leopard frogs to move to the water, making them prey to the bluegills.
The current status of the leopard frogs in Colorado is that the species is becoming endangered. This is mainly due to invasive species, specifically the bullfrog. Leopard frogs have been killed by fertilizers and pesticides that have been put into their environments as well. Grazing animals and droughts have also had a negative effect on leopard frogs due to lack of food and resources to survive. Leopard frogs need to have a nearby water source for reproduction and for survival. Riparian habitats are optimal for leopard frogs as they have water and vegetation. Eggs hatch in 9 or more days, and metamorphosis is completed within 2 months, starting in January and August. Leopard frogs live from one to three years.
Methods & Materials
At the Durango Nature Studies Pond, 4 pitfalls traps were set up and checked daily for frogs that had fallen in overnight. Visual encounter surveys were conducted around the pond for each of the four days. One hour mark sessions and a one hour recapture session was conducted. Water chemistry tests were conducted to record nitrates, phosphates, dissolved oxygen, and pH in the DNS pond and the Florida River. Macroinvertebrates were collected in the river using a kick method as well as a dip net.
Results
The data macroinvertebrate data from 2012 shows there were five damselflies, ten mayflies, two dragonflies, and three riffle beetles in the DNS pond. The overall diversity index was 1.21 using the Shannon-Wiener index. The data showed there were 57 mayflies, 14 midges, 270 caddisflies, 2 dragonflies, 1 blackfly, 11 riffle beetles, and 9 craneflies. The river rated a .88 on the Shannon-Wiener scale. No stoneflies were found in the river, which suggests there is a dangerous level of pollution for stoneflies in the river. Other test taken on the river suggested that both the pond and the river have high phosphate levels, alkaline pH, and high nitrate levels. The pond data suggested that there is low dissolved oxygen, while the river data suggested there are normal levels of dissolved oxygen. Data collected from capture and recapture sessions suggested there is 1 bullfrog and 11 leopard frogs inhabiting the DNS pond.
Conclusion & Discussion
Our data tells us that there is an adequate diversity of macroinvertebrates in the DNS pond, with a diversity of 1.21 on the Shannon-Wiener diversity scale. There is not an adequate amount of diversity in the River, likely due to the overwhelming amount of caddisflies. Not stoneflies were found in the river, suggesting that pollution levels are too high for the organism to survive. Our data also tells us that there is one bullfrog and 11 leopard frogs in the pond. This suggests that there is not a shortage of leopard frogs in the area. We have learned that there is a healthy amount of leopard frogs, and there is no need to worry about populations of leopard frogs due to bullfrogs. The water quality is above average for most of the categories in both the river and the pond, and out data suggests that this could be affecting populations of stoneflies and diversity in the river. I felt as though the process for collecting data was clean and smooth, though catching frogs was a bit difficult because of the speed at which they travel. I do feel as though there was enough time to identify whether or not it was a bullfrog of leopard frog by getting a quick scan of the animal. I feel as though the pond was fine for leopard frogs, as there was only one bullfrog. One bullfrog won’t take up the entire area for good housing, and there is plenty of room for leopard frogs to set up and survive. Phosphates and nitrates are nutrients to keep plants alive. When there are too many phosphates and nitrates, the pond can be at risk of algal bloom. The DNS pond could be at risk of algal bloom, because of high levels of phosphates and nitrates. Normal phosphate levels are .03 ppm, while the pond has levels of 4 ppm. Normal levels of nitrates are 4 ppm, while the river has a nitrate level of 6 ppm. Dangerous levels of nitrates are 40 ppm. The river is at risk of algal bloom, mostly from adequately high levels of phosphates, but is not completely in the danger zone.