Riparian Zone Retreat and Population Studies Sarah Holmes, Biology II, Period I.
Niche of a River Otter Lontra canadensis Habitat must be around a water source Water source can be a river, marsh, lakes, and swamps Can be around a variety of environments including both warm and cooler temperatures Intolerant of polluted waters Temperate and terrestrial areas Varied Habitat across North America Build dens in the burrows of other mammals Usually under a log or in a river bank Dens have underwater entrances and tunnels
Nest chamber with moss, leaves, grass, and hair
Niche of a River Otter continued Mostly carnivore, but can also be an omnivore Eat amphibians, fish, turtles, crayfish, crabs, and other invertebrates Occasionally water plants They may be eaten by bobcats, coyotes, alligators and other large predators Prey is captured and killed by the mouth Use long whiskers to hunt and find prey, especially in dark waters Prey is eaten immediately They usually escape predation because of their abilities in the water and their ability to defend themselves, as well as their young.
They belong to the weasel family
Factors which Affect Birth Rate of the Northern River Otter Breed in late winter, early spring Male and females do not associate with each other until mating time Gestation is about 2 months, but the offspring can be born up to a year later The young is usually born between November and May There are between 1 and 6 young per pregnancy Females give birth and care for their young in their den When they are born, the baby otters are helpless They are weaned at about 3 months and begin to leave their mother at 6 months
They reach sexual maturity at 2 or 3 years
Factors Which Affect the Death Rate of Assigned Animal The River Otter hunts fish, turtles, crayfish, amphibians, and other invertebrates. They are hunted by larger prey such as bobcats and coyotes River Otters that are in captivity can live up to 21 years In the wild, 8 to 9 years There were no common parasites that harm the Northern River Otter
Over population of the otter can result in too many prey and not enough predators or too many predators and not enough prey
Food Chain of Assigned Organism Producer Autotroph Primary Consumer Omnivore Secondary Consumer Carnivore Tertiary Consumer Omnivore
Food web of Assigned Organism This possible food chain shows animals that may be directly or indirectly affected by the Northern River Otter. The animals included, live within the broad habit that the Northern River Otter. Herbivore Producer Omnivore Carnivore Producer Carnivore Herbivore Omnivore Producer Omnivore
Population Sampling Techniques One method would be to gather a small sample or an example sample and measure a specific area of it. Then using that information, calculate the population size (disk lab). A second method is to create a faux ecosystem and randomly choose different organisms and calculate in that way (fake stream) A third method is to set up a mock habitat and calculate the population size by incorporating the predators and prey (spoon and beads).
One population sampling technique used to measure the amount of the river otter would possibly the random circle method because it incorporates most of the factors in an ecosystem.
Stream Quality Data & Analysis This graph shows that there are many different animals within Class I. It shows that this is a healthy stream Since there are several animals in the Class I, the stream is healthy. There are also fewer animals from Class II and Class III; thus, meaning a healthy stream The good stream conditions, meaning that it would be a healthy environment for the river otter.
The food that the otter needs to eat is fish and crayfish, which are higher class organisms.
Water Testing Data & Analysis A neutral pH, usually means that the body of water is healthy. A higher level of dissolved oxygen indicates that a lot of aquatic organisms would be able to live there. High phosphates and nitrate levels indicate that the body of water may not be very healthy. The ideal ranges for the stream at Powdermill would be a neutral pH (7), low to no phosphates and nitrates and a high amount of dissolved oxygen. Some ramifications could be that there was farm runoff, septic tanks that were malfunctioning, or abandoned mine drainage. The Northern River Otter can survive in marsh, but not in mine water, however, if the water was too polluted, then the fish, a food source, might die off. The river otter can also survive in a variety of water temperatures including warm and cool.
Turbidity would make it difficult to hunt for food, which could cause a dying off or overpopulation of the prey.
Soil Testing & Analysis A good ph in soil will assist the plants in utilizing the available nutrients Good levels of Phosphorus will result in plant growth and root formation. Nitrogen is essential to plant metabolism. Potash stimulates flowering, which is necessary for reproduction. The levels of the minerals depend on the ecosystem and the particular plants. pH in soil is usually about 4 Nitrogen is better in medium to high levels Phosphorus is good in high levels Potash is good in higher levels
If the minerals are not at the right level, then it could potentially kill the plant life.
Positive and Negative Factors The river otter can live in a variety of environments It would not be able to live in the mine drainage It would be able to live in the marsh and the stream The soil conditions would not affect the River directly, but it could potentially affect it indirectly through the various plants Some factors that negatively affect the riparian ecosystem would be farm run-off and abandoned mine drainage. Cleaning the mine drainage and controlling levels of farm run-off are two solutions
These factors could affect the river otter, but only in extreme conditions because it can survive in many different environment conditions
Conclusion The Northern River Otter can live in several different conditions including marches, lakes, and streams. One interesting fact is that otters live in dens and they have an underwater, secret entrance to their compartments
One topic that would be interesting to study in the future would be how humans impact the environments and habitats of the River Otter.
Works Cited Northern River Otter. Animal Diversity. http://animaldiversity.ummz.umich.edu/site/accounts/information/Lontra_canadensis.html. 2009 otter . ( 2009). In Encyclopædia Britannica. Retrieved May 1, 2009, from Encyclopædia Britannica Online: http://search.eb.com/eb/article-9057672
“ Otter," Microsoft® Encarta® Online Encyclopedia 2009 http://encarta.msn.com © 1997-2009 Microsoft Corporation.