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Download Notes: Succession (11/18) - Liberty Union High School District
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Succession Monday, November 14th, 2016 Forest Fires ‣ Forest fires are a natural forest development and may naturally occur as a result of: ‣ ‣ lightning strikes concentration of heat on dry tinder. or fire services start controlled burns to remove dry tinder and material that could lead to potentially uncontrollable fires in the future. Photo: CA ‣ In some situations, forestry Surface fires ‣ ‣ ‣ Types of fires Burns undergrowth and leaf litter Kills seedlings & small trees Stimulates germination for some species (giant sequoia & Jack Pine) Crown fires ‣ ‣ ‣ ‣ Occurs in forests that have not had surface fires for a very long time Extremely hot! Leap from treetop to treetop Kills wildlife & increases soil erosion Ground fires ‣ ‣ ‣ Occur underground, burn partially decayed leaves Common in peat bogs Difficult to extinguish Ecological Succession ‣ Succession proceeds in several Pioneer community, Hawaii stages, until the formation of a climax community, which is stable until further disturbance. ‣ Early successional (or pioneer) communities are characterized by: Simple structure, with a small number of species interactions Broad niches Low species diversity Broad niches Climax Communities ‣ In contrast to early successional communities, climax communities typically show: Complex structure, with a large number of species interactions Climax community, Hawaii Narrow niches High species diversity Large number of species interactions Primary Succession ‣ Primary succession refers to colonization of a region where there is no pre-existing community. Examples include: Newly emerged coral atolls & volcanic islands Newly formed glacial moraines Islands where the previous community has been extinguished by a volcanic eruption Paved Parking lots Remember: No soil! Hawaii: Local plants are able to rapidly recolonize barren areas Primary Succession ‣ A classical sequence of colonization begins with lichens, mosses, and liverworts, progresses to ferns, grasses, shrubs, and culminates in a climax community of mature forest. In reality, this scenario is rare. Bare rock and lichens Ferns, grasses and herbaceous Pioneer species. plants Mosses and liverworts Shrubs and fast growing trees Mature, slow growing trees Why lichens are awesome… http://youtu.be/Te4qnLkHnS4 Secondary Succession ‣ Secondary succession occurs where an existing community has been cleared by a disturbance that does not involve complete soil loss. Cyclone ‣ Such disturbance events include cyclone damage, forest fires and landslides. Forest fire Secondary Succession ‣ Because there is still soil present, the ecosystem recovery tends to be more rapid than primary succession, although the time scale depends on the species involved and on climatic and soil factors. Mature forest Bare land Grasses and herbaceous plants Pioneer community (annual grasses) Shrubs and small trees Young fast growing trees Gap Regeneration ‣ The reduced sunlight beneath large canopy trees impedes the growth of the saplings below. ‣ When a large tree falls, a crucial hole opens in the canopy (gap), allowing sunlight to reach the saplings below. ‣ The forest regeneration following the loss of a predominant canopy tree is called gap regeneration. ‣ Gap regeneration is an example of secondary succession. Wangari Maathari and Kenya’s Green Belt Movement ‣ Green Belt Movement: 1977 ‣ ‣ ‣ ‣ ‣ ‣ ‣ ‣ Self-help group of women in Kenya Success of tree planting 50,000 members planted 40 million trees Women are paid for each tree that survives Slows soil erosion Shade and beauty Combats global warming Nobel Peace Prize: 2004 A History of Parks ‣ 1864 – Yosemite was the first designated national park in the world. ‣ 1872 – Yellowstone was established and was the first park to be called a “National Park” •A national park not only provides public access but it affords protection of nature. In the 20th century conservation became the focus of national parks worldwide. •Additionally keep in mind that a goal of park and nature preserve management is maintaining biodiversity in national parks for recreation such as hunting. Who is in charge? ‣ Dept of Interior ‣ ‣ ‣ Bureau of Land Management (BLM) Division of Fish and Wildlife (F&W) National Parks Service (NPS) ‣ Dept of Agriculture ‣ US Forest Service
