19 design of field studies Flashcards
what is the spider web of metal and diamond mining effluent regulations?
what is the goal of this lecture: design of field-based environmental impact assessment studies?
to design a strong environmental impact assessment study, you must know/understand the site characteristics such as:
-water flow, depth, substrate, temperature and other limnological characteristics, biotic community
-you can not design a good monitoring or assessment program without fully understanding the general features of the areas/regions
-you must also understand the nature of the stressor(s). What type of industry? what type of contaminants/stressors?
-you should also understand, as best as possible, what possible confounding factors could be present at each study site
what are the two sampling areas?
reference area= habitat and waters frequently by biota, that is not exposed to contaminant discharge, with characteristics as similar as possible to the exposure area
exposure area= habitat and waters frequented by biota exposed to contaminant discharge
what are the limnological/hydrological factors to consider?
-seasonality: river or stream flow/discharge can be seasonally variable (high flow at snow-melt, late summer drought)
-temperature gradients in lakes (thermoclines)
-plume density relative to the receiving environment
what is plume density?
hypolimnetic sewage discharge versus epilimnetic discharge
what are the common sampling designs?
-control-impact design (C-I)
-before-after control-impact design (BACI)
-multiple control/impact design (MC-I)
-simple gradient (SG)
-radial gradient (RG) design
-multiple gradient design (MG)
-reference condition approach (RCA)
choose the best for your specific field condition and impact assessment (research hypothesis)
what is the graph of control-impact design?
what is the control-impact design?
-ANOVA-type design to detect differences between discrete exposure and reference areas
-this is the simplest design where a reference area is available upstream or in a similar lake environment and there are no other confounding upstream or near-site discharges from other sources
-minimum of one reference and one exposure area
-all factors consistent except exposure to effluent
what is control-impact design when you lake pre-impact (before mining) data?
what is the before-after design when you lack reference site data?
what is BACI design when you have both?
what is the design of environmental impact assessment studies when you have no good reference site?
what is the design of environmental impact assessment studies when you have a reference site?
what is the multiple control-impact design?
what are gradient designs?
-examine changes to benthic invertebrate community structure along a physical and/or effluent gradient (regression-based or ANCOVA designs)
-use this approach if there are no suitable reference areas upstream or on an adjacent stream
-effects along a path of decreasing exposure gradient
what is the simple gradient design in river?
what is the simple gradient design in narrow bay?
what is the radial gradient design in lake or coast?
what are the theoretical results in gradient studies?
what is gradient design without reference site?
what is gradient design with reference site (multiple gradient)?
what is the reference condition approach graph?
what is the reference condition approach?
-reference sites are established based on minimal impacts by human use, and present users with a control for impaired site comparison
-the reference sites represent as many different geographic regions and stream sizes as possible and are used to form groups of organisms representing the various habitat types present
-once the reference condition has been established, sites suspected of being impaired are sampled
-differences between the reference groups and test-site organisms indicate the degree of impairment of the site
what are the sampling recommendations of benthic invertebrates?
what are sub-sampling within field studies (C/I design)
how many samples to collect?
what is the sample size recommendations?
what is the null hypothesis?
