Environmental Geology GLG 110 - CHAPTER 4 - ECOLOGY and GEOLOGY
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Environmental Geology GLG 110 - CHAPTER 4 - ECOLOGY AND GEOLOGY • Ecology – Study of relationships between living things and their environments; the study of control factors over the distribution, abundance, and health conditions of living things o Species – a group of individuals capable of interbreeding o Population – a group of individuals of the same species living in the same are o Community – a group of populations of different species living in the same area, o Habitat – where a particular species lives o Niche – how a particular species makes its living o Indigenous species – species that are found in the area where they evolved (e.g., Kangaroos in Australia) o Exotic species – species brought into an area or region by humans, either purposely or by accident o Invasive species – exotic species which compete with and may replace indigenous species in their habitat o Biosphere – part of Earth where life exists o Biota – all organisms living in an area or region • Environmental Geology - Study of geological processes and their effects on environment • Ecosystem – an ecological community (organisms) and its nonliving (geologic) environment in which energy flows and chemicals (such as nutrients and water) flow (Keller, p. 108) • Succession – the systematic change of species as an ecosystem evolves after a large disturbance (e.g., fire, flood, volcanic eruption) starts things over from scratch o Primary succession – new land surface (e.g., lava flows adding land to island of Hawaii) gets populated o Secondary succession – reestablishment of previously existing ecosystems (e.g., regrowth of forest after a major fire) • Balance of nature in a static state is non-existent – disturbance and change are natural o Humans put themselves in harm’s way and become frustrated when attempting to ignore this fact or rely on it “taking a break” during their lifetimes o Climate change occurs naturally ♣ “Global warming” as currently discussed should be focusing on what portion of the current trend has been artificially increased by man’s activities, not on trying to halt any/all change in climate • Human-constructed ecosystems can be used to aid in cleaning up environmental problems o Marsh plants use and remove nutrients in water that may represent unwanted waste • Plants on steep slopes stabilize soil – naturally/artificially • Removal of helpful ecosystems (like slope vegetation or coastal marshes) can increase hazards to human life and property, such as coastal flooding, and reduce ability to naturally clean the water • Biodiversity – the number/abundance of species in an ecosystem or ecological community o The number or abundance of species in an ecosystem or ecological community ♣ Species richness: the number of species ♣ Species evenness: the relative proportion of species ♣ Species dominance: one of multiple species more common than others ♣ Keystone species: exerting a stronger community effect disproportionate to their abundance. Examples – wolves in Yellowstone, sea otters in kelp forests, bison on prairie, corals o Geology influences biodiversity from small (hillside) to large (mountain range) scales ♣ Example: trees in post-glacial Europe vs. N. America o Increased by diverse habitat with many potential niches, moderate disturbances, harsh environmental conditions in places within a diverse region, relatively constant climate/elevation, heavily life-modified environments o Decreased by extreme or very frequent disturbance (e.g., inside a volcanic crater), extreme environment locally decreases diversity, human transformation of the land (dams, urban sprawl, etc.), pollution and other environmental stresses, habitat simplification (e.g., farming, flood control, etc.), introduction of invasive species, inopportune orientation of mountain ranges (esp. during ice ages) o Urban and agricultural land transformations produced by humans over the past 2000 years have greatly decreased biodiversity and we are in the middle of a human-produced mass extinction • Factors to Increase Biodiversity Ø Favored geological environment Moderate amount of disturbance – hazards creating or renewing habitats Harsh environments for certain unique specialized species, increasing biodiversity at regional scale Ø Relatively constant environmental conditions, such as T, P, precipitation, and elevation Ø Highly modified biologically productive environment • Factors to Reduce Biodiversity ³ Extreme geological environments Ø Disturbances can easily damage extreme habitats Ø Hot springs, caves, hypersaline lakes, extreme cold/aridity Ø Limited number of habitats and ecological niches at a local scale Ø Pollution and other stresses restrict the flow of energy and nutrients ³ Fragmentation of ecosystems by land use transformation ³ Intrusion of invasive exotic species ³ Habitat simplification (engineering structure) or migration barriers • Human Domination o Human activities exerting dominant community effects - Human footprint on the environment – impact we have on our planet can be reduced by either population reduction (gradual vs. catastrophic) or to use resources and manage our waste more efficiently. Impacts include: Ø Massive land use transformation – urban, agriculture, recreation, and industry development Ø Global climate changes (global warming) Ø Changes in biogeochemical cycles – O2, CO2, energy, and nutrients Ø Very rapid extinction (many species) during the last 2000 years Ø Currently in a mass extinction event, caused by humans • Human Time vs. Earth Time ³ Geological processes on Earth time scale • We matter very little on this time scale… ³ Human activities and expectations on human time scale • We matter very much on this time scale… ³ Need to operate with an appropriate environmental ethic ³ Need to make a “pact” with Earth to achieve a more compatible relationship ³ Disrespect and disregard resulting environmental degradation • Reduce the Human Footprint ³ Human population reduction ³ More efficient use of resources ³ Better management of our waste ³ Better understanding of ecosystems ³ The importance of human-dominated ecosystems and other types of ecosystems • Ecological restoration – altering an area in order to recover historical indigenous ecosystems o Waste clean-up o Replanting trees and other plants o Dam removal o Reintroduction of native species o Everglades as a LARGE example o “Big 3” – hydrologic/water conditions/soil and rock/vegetation • Important Restoration Aspects ³ Hydrologic process: surface water & groundwater ³ Soil and rock: Geological conditions (rock and soil type, slope, landscape) ³ Vegetation: the cover materials on land and wetland ³ Socioeconomic shareholders: interests and startpoint ³ Science: restoration goals and endpoints • Biological Engineering in Ecological Restoration ³ Using vegetation in engineering projects to achieve specific ecological goals ³ Designing and constructing certain ecosystems ³ Modifying functions of ecosystems Ø E.g., Solarizing the ice plant of the sand dunes in Santa Barbara Ø Planting native dune vegetation species WSE 8/2012 .