Riparian Zone Retreat and population studies Jake Fox, Honors Biology II, Period 5.
Niche of Elk Cervus Elaphus (Elk) <ul><li>Elk live primarily in open woodlands. They also live in coniferous swamps, clear cuts, aspen-hardwood forests, and coniferous-hardwood forests. They are typically found at elevations of sea level to 3000 meters above. </li></ul><ul><li>Elk depend on plants for food. Elks are herbivores and eat plants, roots, leaves, stems, and some fungi. Normally, elk are not the prey of other animals. Elk have been known to be hunted by bears, mountain lions, grey wolves, and bobcats from time to time. </li></ul><ul><li>Elk do not hunt. They do protect themselves with their large antlers (males) and sharp hooves. </li></ul><ul><li>Elk are seen as pests to some farmers as they can eat to many of their plants while browsing. </li></ul>
Factors which Affect Birth Rate of Elk <ul><li>Elk mate around the fall rut in late September to early October. At this time elk lose the velvet on their antlers and begin to compete for females. Male elks will form large harems of females and defend them from other male elk. Males attract females into the harem, which consist of 1 to 6, by bugling. </li></ul><ul><li>Elk reproduce once per year as nutrition allows. </li></ul><ul><li>An elk’s gestation period is approximately 8 to 8.73 months. </li></ul><ul><li>Generally, 1 offspring is born in each pregnancy, very rarely will two be born. </li></ul><ul><li>A cow (female elk) and her calf will live alone for several weeks so as the cow can care for her calf. A cow will hide her calf in a secluded area to nurse them. Males have no part in the nursing of their young. At about 16 days the calf is able to join the herd and weaning is complete around 60 days. </li></ul><ul><li>Elk begin reproducing in the fall and wont continue until the next fall. </li></ul>
Factors Which Affect the Death Rate of Assigned Animal <ul><li>Elk only affect human crops by sometimes over browsing on human planted crops. Humans also have overhunted elk. Elk only eat plants and the main predator to an elk are bear or mountain lions. </li></ul><ul><li>Elk don’t live long because of overhunting. Elk can live up to 20 years though. </li></ul><ul><li>Elk can be affected or carry parasites such as spongiform encephalopathy, a chronic wasting disease, or meningeal worms. </li></ul><ul><li>Overpopulation of elk is very rare as elk don’t reproduce that quickly or that many as they are hunted heavily for their fur and meat. </li></ul>
Food web of Elk Herbivore Producer Omnivore Carnivore Carnivore Producer Decomposer Herbivore Producer Carnivore Producer
Population Sampling Techniques <ul><li>Ecologists use birth rates, hunting samples, and mark and recapture. Using mark and recapture, they capture a species, mark it, and release it. They then go out and recapture the species, seeing how many are marked, compared to how many are not. </li></ul><ul><li>They use the same mark and recapture technique for finding the population of elk. They capture elk, mark them, release them, and then recapture them. They also use hunting patterns and birth rates of elk. </li></ul>
Stream Quality Data & Analysis <ul><li>The graph represents good stream quality because a high number of class I organisms, which are pollution intolerant, were found. </li></ul><ul><li>The higher the number of class I organisms compared to class II or class III indicates good stream quality. </li></ul><ul><li>The elk drinks lake or stream water, so good quality water benefits the elk. </li></ul><ul><li>If the majority were class III, the overall stream quality would be very poor. The elk and other organisms that depend on water would suffer because the streams would be so polluted. </li></ul>
Water Testing Data & Analysis <ul><li>The higher dissolved oxygen is better for the stream. A dissolved oxygen above 10 is good. A low level of nitrates is better for the stream, as is a low level of phosphates. An ideal pH is neutral, from 6.5-7.5. </li></ul><ul><li>The ideal range for nitrates and phosphates is very low. From about 0-1. This is so plants don’t grow and choke out the organism life. An ideal range of dissolved oxygen is 10-15 ppm, this is the level at which most organisms thrive. An ideal pH range is from 6.5-7.5, which is where most all organisms thrive. </li></ul><ul><li>The elk would better survive closer to the stream where the water it drinks is clean and good for it. If the elk lived next to the marsh or mines, the pH or nitrates would be wrong to the point that it could kill the elk. </li></ul><ul><li>Temperature affects stream life and how much dissolved oxygen is in the stream. The colder the water, the more oxygen (until it freezes). The hotter the water, the less oxygen. Turbidity affects predator-prey relationships. If the water is cloudy than predators may be unable to see their prey. Cloudy water may also clog macro invertebrates gills and thus kill them. </li></ul>
Soil Testing & Analysis <ul><li>Potash, Phosphorus, and Nitrogen are the nutrients needed for plants to grow. pH determines how well plants utilize the nutrients in the soil. All plants have a pH “preference.” </li></ul><ul><li>pH in soil ranges from highly acidic, around 4, to slightly alkaline, 7.5-8. For most soil an ideal range of nitrates is very high. Grass and other plants need high levels to grow well. An ideal range for phosphates in soil is also very high. Phosphates make ATP in plants and help with the formation of roots, making it necessary. Soil should also have high levels of potash so that plants can flower and produce sugars in photosynthesis. </li></ul><ul><li>Chemical levels that are out of the ideal range can cause a stunt in growth of plants. Grass may not come in, certain produce may not grow, or plants in general would not grow as large as normal. </li></ul>
Positive and Negative Factors <ul><li>The Powdermill stream would be perfect for elk. This is the perfect drinking water quality for mammals such as the elk. The marsh water would also be ok for the elk. Not perfect, but not harmful either. The mine water would kill the elk because the water is to acidic. </li></ul><ul><li>Elk feed mostly on plants and grass, so the soil at Powdermill would negatively affect them. The soil was too acidic, 4.5 pH, for grass to grow so this would adversely affect elk. </li></ul><ul><li>Having clean water and a healthy water system will positively impact the riparian zone. Things like excess nitrates, phosphates, acid mine drainage, or just general pollution will very negatively impact the surrounding area. Common sources of pollution in streams include: acid mine drainage, excess nitrates and phosphates, farm land run-off, general pollution, or even acid rain. It is important for us to protect our waterways because that is where all life steams from. Without the base of a healthy stream the rest of the food chain would fall apart. To better protect and preserve our waterways we should limit the amount of farm land run-off and acid mine drainage. We need to find ways to clean the water that is polluted and then ways to keep it clean. A clean, healthy stream makes a healthy elk population. If elk still lived here in Pennsylvania, they would need clean water and looks of plants to feed on. The healthy herds of elk would stem from having healthy streams. </li></ul>
Conclusion <ul><li>I learned that a clean waterway goes a long way to creating a healthy ecosystem. I found a lot of work goes into keeping our streams healthy. </li></ul><ul><li>It was interesting to learn that elk have not lived in Pennsylvania since 1867. </li></ul><ul><li>A topic I may want to research further is the affect of different chemicals on waterways and the invertebrates that live in the waterways. </li></ul>
Works Cited <ul><li>Senseman, R. 2002. "Cervus elaphus" (On-line), Animal Diversity Web. Accessed May 12, 2010 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Cervus_elaphus.html. </li></ul><ul><li>" elk ." Encyclopædia Britannica . 2010. Encyclopædia Britannica Online. 12 May. 2010 < http://www.britannica.com/EBchecked/topic/184943/elk >. </li></ul><ul><li>Bowman, Mrs. Biology II Notes . Ligonier: Biology II, 2010. Print. </li></ul>
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