* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Field Ecology - Napa Valley College
Storage effect wikipedia , lookup
Conservation psychology wikipedia , lookup
Ecological resilience wikipedia , lookup
Molecular ecology wikipedia , lookup
Plant defense against herbivory wikipedia , lookup
Renewable resource wikipedia , lookup
Agroecology wikipedia , lookup
Plant breeding wikipedia , lookup
Deep ecology wikipedia , lookup
Habitat conservation wikipedia , lookup
Biogeography wikipedia , lookup
Biological Dynamics of Forest Fragments Project wikipedia , lookup
Reconciliation ecology wikipedia , lookup
Cultural ecology wikipedia , lookup
Restoration ecology wikipedia , lookup
Ecological succession wikipedia , lookup
Ecological fitting wikipedia , lookup
Soundscape ecology wikipedia , lookup
Field Ecology BIO 112 Intro. to Ecology Summer 2015 (McDill) Overview Disturbance and Succession Ecology is the study of the interaction of organisms with their physical environment and with each other. Ecologists try to discover how an organism affects, and is affected by, the biotic (living) and abiotic (nonliving) factors in its environment. They are also interested in knowing how these interactions determine the numbers and kinds of organisms found in a particular place at a particular time. Indeed, one alternative definition of ecology is “the study of why organisms live where they do.” Ecologists conduct their investigations both in the field and in the laboratory, and the data obtained from their investigations are both qualitative and quantitative. Communities change over time. Some changes are in response to external natural forces, including long-term climatic changes, geological changes, and catastrophic events such as fire, drought, or hurricane (or a bulldozer being driven through a field). Sudden changes are sometimes characterized as “disturbance.” Other changes may be due to the growth of organisms. For example, the growth of pioneer plant species may make conditions more suitable for non-pioneer species. Aspen trees may give way to spruce; annual forbs (herbaceous plants that are not grasses) may give way to prairie grass. This progressive change in community composition or vegetation type (e.g. meadow to woodland to forest) is referred to as ecological succession. Disturbance often sets the stage for succession to occur. Long before the word “ecology” was coined, there was a tradition of observation and enjoyment of organisms in their natural environment. For people of early hunting-and-gathering cultures, survival depended on good observations. The intense interest in observing firsthand the world’s organisms and their environments led early plant geographers and naturalists, including Alexander von Humboldt and Charles Darwin, on incredible journeys that greatly increased our understanding of the natural world. A qualitative description of the Danube River basin by A. von Marilaun Kerner (1865) is often considered to be the first ecological work. The term population refers to all members of the same species within an area. The biotic community is the assemblage of interacting populations of different species that inhabit the same general environment. The biotic community and the physical factors of the environment interact as a dynamic ecological system, or ecosystem. Is there any evidence of disturbance or succession at any of the sites we visit? By the end of the course, you will have visited several contrasting ecosystems. Your field notes should include information provided by the trip leader as well as your own observations. Qualitative (descriptive) observations provide ecological insights and often precede the formulation of hypotheses that are tested quantitatively (i.e. through analysis of numerical data). Qualitative Observations in the Field For each terrestrial ecosystem, such as the oak woodlands, chaparral, and tidal marsh, make observations of the biotic community in relation to its physical environment; interactions between organisms; and any evidence of change in the communities. Fie Field Ecology 1 The Biotic Community and its Physical Environment After the trip… Physical Environment 1. At each site, record your general observations of the steepness and direction of the slope, exposure to prevailing winds, light intensity air and soil moisture, and temperature. Organize the data (your observations) under ecological categories. The following may serve as guidelines. You may want to add additional categories or organize things differently. 2. 3. Note general soil characteristics, such as very sandy texture, bedrock near the surface, and poor drainage. Estimate the leaf-litter depth. The Biotic Community 4. Using biomass (bulk) as the criterion for dominance, identify the plant forms that seem to dominate the community 5. Are there different layers, or vertical structure, in the area/habitat— for example, a canopy, an understory, and a groundcover layer? 6. Are the abiotic factors the same in each layer? 7. What plant forms are most typical of each layer? 8. With the help of your instructor and/or any field guides brought along, identify some of the plant species in each layer and discuss some of the ways in which these plants are adapted to their environment. 9. 1. Finally, review your observations and relate the community at each site to its physical environment. 10. In what ways have specific physical factors limited and determined the plant life of the communities? 2. 3. 4. 5. Food webs or Trophic Level (flow of energy and nutrients) a. Herbivory b. Predation c. Decomposition Symbioses a. Mutualism b. Parasitism c. Commensalism Competition a. Interspecific b. Intraspecific Habitat Structural Features a. Food source b. Water source c. Protection/cover d. Den/nest sites Modification of Environment a. Leaf litter b. Shade c. Soil compaction d. Etc. 11. As you explore each community, record any evidence you see of interactions between two plants, between two animals, or between a plant and an animal. For example, note the pattern of holes in a leaf, the presence of a bird nest in a bush, a bee on a flower, moss or lichen on a log, and any droppings or other physical evidence (flattened grass) of an animal’s passing. Note also any plant adaptations that may discourage or encourage interactions (such as spines to prevent herbivory). Fie Field Ecology 2