Appendix Biota Sampling and Survey Methods The biota of contaminated and reference sites may be sampled to obtain tissues for residue or biomarker analysis (Section 3.1.2) and may be sampled or surveyed for estimation of effects (Section 4.3). Methods for sampling or surveying biota that are potentially applicable for residue analyses at contaminated sites are briefly discussed below (Sections A.1 to A.11). Methods for performing habitat surveys as a means of determining what wildlife species should be present are presented in Section A.12. Sampling considerations, including selection of tissues to collect, appropriate methods of killing collected organisms, and health concerns for sampling personnel, are presented in Section A.13. A.1 FISHES Sampling techniques for fish include electrofishing, nets, and traps. Selection of the appropriate method depends on the species of interest and the type of aquatic system being sampled. In electrofishing, an electric current, supplied by a gasoline- or battery-powered generator to a set of probes placed in the water, is employed to stun fish which are then captured with a net. The advantages of electrofishing include that it is effective for both juveniles and adults of most species and for sampling structurally complex habitats, and it efficiently samples large areas in a relatively limited time while capturing a large percentage of individuals within an area. Numerous studies indicate that under proper conditions, electrofishing can be the most effective sampling technique (Jacobs and Swink, 1982; Wiley and Tsai, 1983; Layher and Maughan, 1984). Disadvantages include potential mortality (which may be a significant issue if sampling is repeated or if highly valued species are present); low efficacy for benthic or deep-water species, for very low- or high-conductivity water, and for turbid water; and potential hazards to users. Additional information on electrofishing can be found in Hartley (1980) and Reynolds (1983). A wide variety of nets and traps are used to sample fish populations or commu- nities. Two basic types exist, nets that snag or entangle fish and traps or net arrange- ments that provide a holding area into which fish are enticed. The most common entanglement nets are gill nets and trammel nets that use an open mesh through which fish attempt to swim. As the fish attempts to pass through, gill covers or fins become snagged on the fine filament netting. Gill nets are generally more effective in turbid water and areas without snags (Hubert, 1983) and are effective for sampling deep areas not accessible by other techniques. Gill nets are also highly effective for a variety of larger fish sizes (depending on mesh size used), and for fast-swimming or schooling species. Disadvantages include potential injury or mortality of snagged © 2000 by CRC Press LLC fish; the limited range of fish sizes sampled by any one gill net mesh size; the high rate of capture of nontarget species, resulting in an increase in sampling time and total mortality; low success for fish species with low mobility (e.g., sunfish); and highly variable results. Further details are given in Hartley (1980), Hamley (1980), and Hubert (1983). Stationary fish traps include fyke nets, hoop nets, trap nets, and pot gear (e.g., slat baskets and minnow traps). All of these devices work by allowing the movement of the fish to take them through a small opening into a larger holding area. Stationary traps are available in small (minnow traps) to large (fyke nets) sizes, allowing multiple species and life stages to be sampled. Because fish remain alive while in the trap, the traps do not need to be checked as frequently as entanglement nets. Stationary traps are effective for cover-seeking species (e.g., sunfish) or benthic species (e.g., catfish). Disadvantages of these traps include high variance in efficiency across species and susceptibility of catch rates to changes in temperature and tur- bidity. The larger fyke, trap, and hoop nets are most effective in reservoirs, ponds, lakes, and river backwaters. Pot gear and smaller hoop nets can be more effective in smaller streams or faster water. In both cases, traps can be combined with weirs or directional structures that channel fish into areas where the traps are deployed. Additional discussions can be found in Craig (1980) and Hubert (1983). A.2 PERIPHYTON Sampling techniques for periphyton entail scraping, coring, or suctioning the per- iphyton from the substrate. The substrate may be natural or artificial. Method details are presented in APHA (1999). Periphyton samples are generally collected from hard substrates, for which most of the available techniques are appropriate and relatively straightforward. Periphyton are less commonly collected from soft sediments, because this is more difficult and time-consuming than sampling hard substrates (Warren-Hicks et al., 1989). Soft substrates are collected via suction and then the individual algae must be sorted from the sediment material for identification and quantification. Artificial substrates are placed in the water and the periphyton are allowed to colonize the substrate. Typically, the samples are collected after 2 to 4 weeks, although a longer colonization period may be needed in nutrient-limited systems (Rosen, 1995). A common and widely accepted artificial substrate is frosted glass slides. The slides are held in a frame that can be suspended in the water at a given depth (APHA, 1999). Other commonly used materials include ceramic tiles, plastic strips, and granite slabs (Warren-Hicks et al., 1989). The periphyton are removed from a measured area of the substrate by scraping, coring, or suctioning and are preserved for analysis. Natural substrates are generally less uniform in surface texture than are artificial substrates, and the periphyton are generally more patchily distributed (Rosen, 1995). If a sample of a specified area is to be removed from a rough substrate, the sampler should be designed to fit snugly against the surface. This is generally accomplished by using samplers that have neoprene rubber seals around the edge of the sampler. Alternatively, the periphyton can be scraped or brushed from the entire piece of natural © 2000 by CRC Press LLC substrate, provided the sample units are suitably small. In this case the surface area of each sampling unit of natural substrate must be measured, which can be accom- plished using aluminum foil following the procedures outlined by Coler et al. (1989). A.3 PLANKTON Sampling equipment for phytoplankton and zooplankton include closing samplers, traps, pumps, and nets (APHA, 1999; Office of Emergency and Remedial Response, 1994b; Warren-Hicks et al., 1989). Samples may be collected from discrete depths or be integrated over a range of depths or horizontal distances. Method selection depends on the target organisms, target depths, and desired sample quality. Discrete-depth samplers include closing tubes or bottles, traps, and pumps. Closing tubes (e.g., Van Dorn and Kemmerer models) are quantitative for all sizes of plankton, including nanoplankton and ultraplankton (Warren-Hicks et al., 1989). The tube (or bottle) is lowered to the desired depth and closed via a weighted messenger. Multiple discrete depths can be sampled simultaneously by hanging multiple samplers in series. Trap samplers operate on the same principle as the closing samplers, but are generally much larger (10 to 30 liters). The larger volume helps ensure that less common species and agile zooplankton are collected (Warren-Hicks et al., 1989; APHA, 1999). However, their large size also makes them ungainly to operate. Pump samplers consist of a weighted sampling hose that is lowered to a selected depth and a submerged or boat-mounted pump. Pumps can be motorized or manual, and common types include diaphragm pumps, peristaltic pumps, and centrifugal pumps. Sample volume can be determined by using a receptacle of known volume or a flow meter, thus allowing the operator to increase or decrease the sample size easily depending on the apparent organism density at the time of sampling (Warren- Hicks et al., 1989). Volume can be measured accurately, resulting in quantitative samples of most plankton. The exception is agile zooplankton, which may be able to avoid the pump head (APHA, 1999). Disadvantages of pumps include the large size of the typical pump, high cost, and damage to the organisms. Integrated-depth samplers include pumps, depth-integrating column samplers, and nets. Pumps are operated as for discrete-depth samples, except that the pump head is moved through the water column at a specified rate. Depth-integrated column samplers are long closing samplers used in shallow water. They collect a quantitative sample, but their ungainly size (to several meters in length) makes them difficult operate (Warren - Hicks et al., 1989). Towed nets provide quantitative samples of zooplankton. Net samples are only qualitative for phytoplankton, because the mesh size (e.g., 60 to 80 µ m) is too large for nanoplankton and ultraplankton (Warren - Hicks et al., 1989). Net samplers can be towed vertically or horizontally, and specific depths or distances can be sampled by using closing net samplers (e.g., Birge closing net). A.4 BENTHIC INVERTEBRATES Many techniques are suitable for the collection of benthic macroinvertebrates for exposure evaluation. These methods include grab-and-core samplers for standing © 2000 by CRC Press LLC waters and kick sampling, Surber samplers for running water, and artificial sub- strates (Murkin et al., 1994). Exposure of benthic invertebrates may also be evalu- ated using in situ exposure of organisms, particularly bivalve mollusks, maintained in a holding device. Grab samplers such as the Ekman, Petersen, Ponar, and Smith-McIntyre sam- plers may be used to collect organisms from deep-water habitats. These devices engulf a portion of sediment (and its associated organisms), which is then hauled to the surface for processing. Organisms are separated from the sample material by washing the sediment in a box screen. Grab samplers are generally easy to use and are suitable for a variety of water depths. Depth of sediment penetration may vary with sediment type, and rocks or other obstructions may prevent complete closure, resulting in partial sample loss. Because grab samplers tend to produce large samples, processing effort may be considerable (Murkin et al., 1994). Isom (1978) reviewed several types of grab samplers, their specifications, the type of substrate each was designed for, and advantages and disadvantages associated with each type. Standard methods for the collection of benthic invertebrates using various types of grab samplers are also presented in ASTM (1999). Core samplers may be employed in both shallow and deep water and consist of a metal or plastic tube which is inserted into the substrate. When the tube is removed, samples of both the sediment and organisms are obtained (Murkin et al., 1994). The samples are then washed in a sieve and the organisms are removed from the remain- ing sample debris. Core samplers are inappropriate for loose or unconsolidated sediment, sand, or gravel (Murkin et al., 1994). Additional information on core sampling can be found in Smock et al. (1992) and Williams and Hynes (1973). Kick sampling is a simple method used in running waters. A net is placed against the streambed, and the substrate upstream of the mouth of the net is agitated for a defined time period to suspend the organisms, which are then washed into the net by the current (Murkin et al., 1994). While this method is easy, the exact area sampled is undefined, and therefore it is unsuitable in instances when quantitative samples are needed. When quantitative samples from running water are needed, Surber samplers should be used. Surber samplers consist of a frame with an attached net. The frame is placed on the streambed, the substrate within the frame is disturbed, and rocks and other debris are rubbed to dislodge invertebrates. Water current carries inverte- brates into the sampling net (Murkin et al., 1994). Standard methods for the collec- tion of benthic invertebrates using Surber and related samplers are presented in ASTM (1999). Artificial substrates do not provide estimates of actual benthic community prop- erties but can provide quantitative estimates of artificial community metrics relative to artificial substrates in reference streams. The most common artificial substrate is the Hester–Dendy multiple-plate sampler (APHA, 1999), or modified versions thereof. These samplers have a known surface area (generally about a square foot) consisting of tempered hardboard plates and spacers mounted on an eyebolt creating multiple parallel surfaces separated by spaces of one, two, and three spacer thick- nesses. Replicate samplers are deployed at each sampling location. Care is taken to ensure that the samplers are completely submerged and oriented with the plates © 2000 by CRC Press LLC perpendicular to the current. Artificial substrates are selective of certain species and do not represent rare species or the actual taxa richness of a system. However, they are relatively quick and easy to use, provide standardized and repeatable results, and are often recommended or accepted by regulatory agencies (DeShon, 1995). The basket sampler is a variant of the artificial substrate sampler (APHA, 1999). It consists of a wire basket filled with rocks or rocklike material. It is deployed in the same manner as multiplate samplers. However, rocks similar to those found in- stream can be used as the substrate, possibly reducing the bias associated with the artificial materials. Standard materials (e.g., limestone rocks) eliminate much of this advantage over multiplate samplers. The surface area of all nonuniform substrates must be measured, which adds effort and some uncertainty to the sampling process. D-framed or rectangular nets can be used for kick, sweep, or jab sampling (Barbour et al., 1997). The major advantage of these nets is that all habitats can be sampled relatively easily. But the results are, at best, semiquantitative. Qualitative samples require little or no consideration of effort or distance sampled. Semiquan- titative samples are generated when a standard distance or duration of effort is used for all sites (Barbour et al., 1997). Contaminant exposure of benthic invertebrates may also be evaluated through in situ exposure of individuals of a surrogate species (Peterson and Southworth, 1994; Salazar and Salazar, 1998; ASTM, 1999). The selected organisms are held in polypropylene mesh cages, which are placed in the area of potential contamination and each reference site. After the prescribed period of exposure (generally 4 weeks), the organisms are analyzed for contaminants and levels are compared with those from organisms caged at the reference sites. Indigenous organisms should be used to prevent the unintentional introduction of exotic species where they do not exist. A.5 TERRESTRIAL PLANTS Collection of plant material for residue analyses is a simple procedure. After plants of the appropriate species are identified, they may be sampled either as whole organisms (roots plus aboveground parts), as aboveground parts, or as discrete parts (roots, foliage, seeds, fruit, etc.). Samples may be collected by stripping or breaking parts from the plant, by cutting plant parts with shears, or by digging up plants with a spade. Additional information on vegetation sampling for residue analysis may be found in Sprenger and Charters (1997), Environmental Response Team (1996), DOE (1987), and Temple and Wills (1979). A.6 TERRESTRIAL MOLLUSKS Methods for the collection of terrestrial mollusks (snails and slugs) are not as well defined as those for other terrestrial invertebrates. Collection methods include the use of bran- or metaldehyde-baited traps or refuge traps (boards placed at a site to attract slugs; Newell, 1970). Snails or slugs may also be extracted from litter or soil collected from the site. Snails will generally float and slugs sink when the samples are immersed in water. Although population estimates of snails may be made by counting their abundance within randomly placed quadrants, this method is likely © 2000 by CRC Press LLC to be biased toward adults and against immatures (Newell, 1970). Additional dis- cussion of sampling and extraction of terrestrial mollusks may be found in Newell (1970) and Southwood (1978). A.7 EARTHWORMS The primary methods for collection of earthworm samples are hand sorting of soil, wet sieving, flotation, and application of expellants. Hand sorting is regarded as the most accurate sampling method, and is frequently used to evaluate the efficacy of other methods (Satchell, 1970; Springett, 1981). While accurate, hand sorting is very laborious and may underestimate the abundance of small individuals. Efficiency is dependent on the density of the root mat, clay content of the soil, and weather conditions if sorting is done in the field. Wet sieving uses a water jet and a sieve to separate earthworms from the soil (Satchell, 1970). The efficiency of this method is not documented, and worms may be damaged during washing. Flotation consists of placing soil samples in water and collecting earthworms as they float to the surface (Satchell, 1970). This method may be used to extract egg capsules and adults of species too small to recover efficiently by hand sorting. In contrast to methods that require excavation and processing of soil, expellants are applied in situ to collect earthworms. In practice, an expellant solution is applied to the soil surface within a sampling frame and allowed to percolate. Earthworms are then collected as they emerge from the soil. To enhance absorption of the expellant by the soil and to facilitate collection of earthworms as they emerge, vegetation at each sampling location should be clipped down to the soil surface. Expellants have traditionally consisted of formaldehyde or potassium permanganate solutions (Raw, 1959; Satchell, 1970). Drawbacks to these expellants include car- cinogenicity, phytotoxicity, and toxicity to earthworms. In addition, these expellants may introduce additional contamination and interfere with residue analysis. As an alternative, Gunn (1992) suggested the use of a mustard solution as an expellant. A commercially available prepared mustard emulsion was mixed with water at a rate of 15 ml/l and applied to soil within a 1-m 2 frame (to confine the expellant). Efficacy of mustard was found to be superior to formaldehyde and equivalent to potassium permanganate (Gunn, 1992). Recent work at Oak Ridge National Laboratory indi- cates that a suspension of dry mustard (1 tsp/l) is also an effective expellant (B. Sample, personal observation). If worm samples are being collected for residue analysis, analyses should be performed on samples of the mustard expellant. These data will indicate if any contamination can be attributed to the extraction method. A.8 TERRESTRIAL ARTHROPODS Many methods are available to sample terrestrial arthropods. Because of the great diversity of life-history traits and habitats exploited by arthropods, no single method is efficient for capturing all taxa (Julliet, 1963). Every sampling method has some associated biases and provides reliable population estimates for only a limited number of taxa (Kunz, 1988a; Cooper and Whitmore, 1990). Reviews of sampling methods for insects and other arthropods were given by Southwood (1978), Kunz (1988a), Cooper and Whitmore (1990), and Murkin et al. (1994). Descriptions of © 2000 by CRC Press LLC 12 commonly employed methods, arthropod groups for which they are appropriate, and advantages and disadvantages of each are summarized in Table A.1. A.9 BIRDS A.9.1 S AMPLING B IRDS Methods to collect birds include firearms, baited traps, cannon nets, mist nets, drive and drift traps, decoy and enticement lures, and nest traps (Schemnitz, 1994). Methods employed depend upon the species to be sampled. Additional information concerning methods for capturing birds may be found in Schemnitz (1994), the “North American Bird Banding Manual” (U.S. Fish and Wildlife Service and Cana- dian Wildlife Service, 1977), Guide to Waterfowl Banding (Addy, 1956), and Bird Trapping and Bird Banding (Bub, 1990). Firearms used to collect birds may include rifles, shotguns, or pellet guns. This method, while highly dependent on the skill of field personnel, may be used for all groups of birds. However, because samples may be extensively damaged during collection, projectiles or shot may interfere with residue analyses, and because of safety considerations, the use of firearms is not a recommended sampling method. In addition, the use of firearms for sample collection precludes repeated sampling of the same individual. Baited traps are most useful for gregarious, seed-eating birds. In their simplest form, a wire-mesh box is placed over bait (generally seeds or grain), and one side is supported by a stick. Once birds enter the box to feed, the operator pulls a string attached to the support stick, the side falls, and the birds are entrapped. Other types of baited traps include funnel or ladder traps. These traps are designed with entrances through which birds can easily enter but not easily exit. Cannon nets may be used for birds that are too wary to enter traps. This type of trap is frequently used for wild turkey and waterfowl and has been successfully used for sandhill cranes and bald eagles (Schemnitz, 1994). Cannon nets consist of a large, light net that is carried over baited birds by mortars or rockets. In use, nets are laid out and baited for 1 to 2 weeks to allow the birds to become accustomed to the net and bait. Once birds make regular use of the bait, the trap may be deployed. Mist netting is a method useful for some species that are not attracted to baits. A detailed review of the use and application of mist nets is provided by Keyes and Grue (1982). This method may be used for birds as large as ducks, hawks, or pheasant but is most applicable to passerines and other birds under approximately 200 g. Mist nets are constructed from fine, black silk or nylon fibers; the nets are usually 0.9 to 2.1 m wide by 9.0 to 11.6 m long, attached to a cord frame with horizontal cross braces called shelfstrings (Schemnitz, 1994). The net is attached to poles at either end such that the shelfstrings are tight but the net is loose. The loose net hangs down below the shelf strings, forming pockets. When properly deployed, birds (or bats) strike the net and become entangled in the net pocket. Mist nets may be employed passively or actively. In a passive deployment, nets are set across flight corridors, and birds are caught as they fly by. For an active deployment, a group of nets is set and birds are driven toward the nets. Another effective approach is to use recorded calls of conspecifics or distress calls to attract birds to the net. © 2000 by CRC Press LLC The following must be considered when using mist nets. • Avoid windy conditions; wind increases the visibility of the net. • Check nets frequently; unintended mortality may result from stress if birds are left in the net for >1 h. • Do not operate nets during rain; birds may become soaked, and mortality may result from hypothermia. Drive and drift traps consist of nets or low wire-mesh fencing erected at ground level. Birds are driven or herded into the fence, which then guides them into an enclosure. This method is most frequently used to capture waterfowl while they are molting and flightless. Drift traps have also been used successfully with upland game birds, rails, and shorebirds (Schemnitz, 1994). Because many birds are reluctant to flush and fly when birds of prey are present, trapping success may be enhanced by playing recorded hawk calls. Decoy and enticement lures are used most frequently for birds of prey. The most common trap of this type is the bal-chatri trap. This trap consists of a wire-mesh cage, on top of which are attached numerous monofilament nooses. A small bird or rodent is placed in the trap as bait. When a hawk or owl attempts to attack the bait, its feet become entangled in the nooses. Nest traps are useful to capture birds at the nest for reproductive studies. For ground-nesting birds, drop nets erected over the nest are sometimes effective. For cavity-nesting birds, trip doors may be devised that can be closed once the adult enters the nest. Other types of nest traps are summarized by Schemnitz (1994). A.9.2 A VIAN P OPULATION S URVEY M ETHODS Many methods are available to determine the abundance, density, and spatial distri- bution of birds. These methods may be used to census populations of a single species or to census the entire avian community in a given area. The commonly used methods are territory mapping, transects, point counts, mark-recapture, song tapes, aerial counts, and habitat-focused surveys. A.9.2.1 Territory Mapping Territory mapping is among the most accurate and reliable methods for determining bird population density (Wakely, 1987a). This method consists of plotting (by indi- vidual species) the locations of birds seen or heard during repeated visits (generally eight to ten). A gridded sampling plot is used for this purpose (Verner, 1985; Ryder, 1986; Wakely, 1987a). Clusters of observations are assumed to represent the center of activity for individual territories. The total number of birds on a plot is then estimated by summing the number of clusters (i.e., territories) and multiplying by 2 (assuming an even sex ratio) (Verner, 1985). This method works best for species that sing conspicuously from within their territories (e.g., most passerines). It is not well suited for birds that frequently sing within the boundaries of a conspecific’s territory, or quiet or secretive species, or nonterritorial birds (called floaters), or species with territories larger than the study plot (Verner, 1985). Also, because the efficacy of this method depends on territorial behavior, it is useful only during the © 2000 by CRC Press LLC breeding season (except for birds that maintain year-round territories). This method also requires considerable time to lay out and mark the sampling plot and for repeated visits. Additional limitations of territory mapping are summarized by Oelke (1981). Falls (1981) reports that detection of individuals may be enhanced by using playback of recorded songs. Birds defend their territories in response to the song tape and their singing locations provide an indication of the boundary of a territory. The consecutive-flush technique (Whitmore, 1982; Verner, 1985) may be used to reduce the number of plot visits needed to complete a territory map. An observer simply approaches a singing bird until it flushes. Its initial position, line of flight, and landing position are then recorded on the plot map. The observer again approaches and flushes the bird and records its movement. The process is repeated until at least 20 consecutive flushes have been mapped. This technique is most applicable in open habitats such as grasslands or marshes, where an observer may keep an individual bird under constant observation. Flushing may also help delineate territory boundaries in forested habitats (Verner, 1985). A.9.2.2 Transects Transect census methods consist of counting birds either seen or heard along one or both sides of a line through one or more habitats (Ryder, 1986). Transects are more flexible than are mapping methods. Because they do not depend on territoriality, their use is not restricted to the breeding season. In addition, they may detect both floaters and juveniles. Verner (1985) defines three general types of transects. 1. Line transects without distance estimates. The observer simply walks a preset line and records all birds seen or heard, without measuring or estimating distances to the birds. This is an efficient method for generating lists of species. However, the results cannot be used to estimate density because the area sampled is unknown. Data may be used for intraspecies or interspecies comparisons (either temporal or spatial), if it is assumed that all individuals or species are equally detectable in all samples and factors that affect detectability are similar among all samples. 2. Variable-width line transects. This is the most commonly used transect method. Perpendicular distances from the transect line to birds detected are measured or estimated. These observations are then used to estimate the area sampled and, thus, bird density. 3. Belt transects. This method is essentially a line transect with fixed bound- aries (usually 25 to 50 m on either side of the line), within which all birds seen or heard are counted. This is a simpler method than the variable- width transect method because the observer need only estimate one dis- tance, the belt width. Density estimates are obtained by dividing the total number of birds observed by the area of the belt. Burnham et al. (1980) provide a very detailed discussion of line-transect techniques, applications, and data analysis methods. Additional discussion is pro- vided by Wakely (1987b). Analytical methods for line-transect data are discussed by Krebs (1989). © 2000 by CRC Press LLC A.9.2.3 Point Counts Point counts consist of counting the number of birds seen or heard for a fixed time in all directions from a single point. Similar to transects, distances around the sampling point may be undefined, fixed, or variable (Verner, 1985). With the variable circular plot method (Reynolds et al., 1980), the distance from the sampling point to the bird is estimated. This distance is then used to estimate the population density. Because point counts do not depend on territorial behavior, they may be performed year-round. Best results, however, are obtained during the breeding season. Although point counts may be performed in any habitat where transect sampling would be applicable, point counts are best suited for steep, rugged, or thickly vegetated habitats where observer movement along the transect may disturb birds and interfere with their detection (Reynolds et al., 1980; Ryder, 1986; Wakely, 1987c). Use of point counts to survey birds in bottomland hardwood forests is discussed by Smith et al. (1993). A.9.2.4 Mark–Recapture The ratio of marked individuals to unmarked individuals may be used to estimate population size. Population size and area sampled can then be used to estimate density. Karr (1981) suggests using mist nets (see Section A.9.1) to capture and color-band birds for population studies. Although mark-recapture is not considered an efficient population census method for birds (Verner, 1985; Ryder, 1986), it may provide very useful information, particularly in studies of threatened and endangered (T&E) species. For example, mark-recapture data may be used to identify the number of pairs of a species that are present, or to distinguish migrants from residents and breeders from nonbreeders, or to identify ranges or territorial boundaries for indi- vidual birds (Ryder, 1986). Additional discussion of the use of mark-recapture to estimate avian populations is presented by Nichols et al. (1981) and Jolly (1981). Analytical methods for mark-recapture data are discussed by Krebs (1989). A.9.2.5 Song Tapes Censusing inconspicuous or secretive birds (i.e., nocturnal, marsh, or some forest birds) may be very difficult. Johnson et al. (1981) and Marion et al. (1981) suggest that song tapes may be employed to perform relative or absolute censuses for these species. By playing recordings in different areas and recording occurrence and number of responses, presence, abundance, and density may be estimated. A.9.2.6 Aerial Counts Large flocks of waterfowl and shorebirds may be photographed from the air and later counted (Verner, 1985). Aerial counts are also suggested for breeding osprey (Swenson, 1982). Because osprey nests are large and conspicuous and generally placed in trees or atop artificial structures, they may be clearly observed from the air. Census flights should be made during the incubation period (generally April through June) using a high-winged aircraft or a helicopter. It should be noted, however, that aerial counts are suitable only for very large contaminated sites. Analytical methods for aerial survey data are discussed by Krebs (1989). © 2000 by CRC Press LLC [...]... Occurring in or by the edge of a stream or in its floodplain risk assessor: An individual engaged in the performance of the technical components of risk assessments Risk assessors may have expertise in the analysis of risk or specific expertise in an area of science or engineering relevant to the assessment risk characterization: A phase of ecological risk assessment that integrates the exposure and stressor... Washington, D.C Barnthouse, L W 1993 Population-level effects In G W Suter II (Ed.), Ecological Risk Assessment Lewis Publishers, Boca Raton, FL 247–274 Barnthouse, L W 1996 Guide for Developing Data Quality Objectives for Ecological Risk Assessment at DOE Oak Ridge Operations Facilities ES/ER/TM-815/R1 Environmental Restoration Risk Assessment Program, Lockheed Martin Energy Systems, Oak Ridge, TN © 2000 by... example, Thompson (1982) describes a habitat-focused survey method for the red-cockaded woodpecker Redcockaded woodpeckers are a colonial-nesting T&E species that require mature, open, fire-maintained pine forests (Thompson, 1982) Survey methods for this species rely on identification of appropriate habitat (old-growth pine forest) and nest trees within the habitat (large-diameter trees with clear boles and... spatial distribution of plant roots scoping assessment: A qualitative assessment that determines whether a hazard exists that is appropriate for a risk assessment It determines whether contaminants are present and whether there are potential exposure pathways and receptors screening assessment: An assessment performed to determine the scope of a definitive assessment by eliminating from further consideration... via soil ingestion in pronghorns and in black-tailed jackrabbits J Range Manage 41:162–166 ASTM 1994 Emergency standard guide for risk- based corrective action applied to petroleum release sites ES 3 8-9 4 American Society for Testing and Materials, Philadelphia ASTM 1999 Annual Book of ASTM Standards, Sec 11 Water and Environmental Technology American Society for Testing and Materials, Philadelphia, PN... with environmental media (soil, sediment, water) from a contaminated site analysis of effects: A phase in an ecological risk assessment in which the relationship between exposure to contaminants and effects on properties of endpoint entities are estimated along with associated uncertainties analysis of exposure: A phase in an ecological risk assessment in which the spatial and temporal distributions... any of the media or receptors on a contaminated site A remedial action under CERCLA must meet all ARARs independent of the associated risks assessment endpoint: An explicit expression of the environmental value to be protected An assessment endpoint must include an entity and specific property of that entity assessor: An individual involved in the performance of a risk assessment background concentration:... exposure for the scenarios described in the conceptual model exposure–response profile: The product of the characterization of ecological effects in the analysis phase of ecological risk assessment The exposureresponse profile summarizes the data on the effects of a contaminant, the relationship of the measures of effect to the assessment endpoint, and the relationship of the estimates of effects on the assessment. .. other lines of evidence, to estimate risks Each line of evidence is qualitatively different from any others used in the risk characterization In ecological risk assessments of contaminated sites, the most commonly used lines of evidence are (1) biological surveys, (2) toxicity tests of contaminated media, and (3) toxicity tests of individual chemicals lowest observed adverse effect level (LOAEL): The... remedial goal for receptors exposed to the contaminated medium probable effects level (PEL): The geometric mean of the 50th percentile of effects concentrations and the 85th percentile of no effects concentrations in coastal and estuarine sediments (Florida Department of Environmental Protection) problem formulation: The phase in an ecological risk assessment in which the goals of the assessment are . relevant to ecological risk assessment is increased. As an example, Thompson (1982) describes a habitat-focused survey method for the red-cockaded woodpecker. Red- cockaded woodpeckers are a colonial-nesting. are present); low efficacy for benthic or deep-water species, for very low- or high-conductivity water, and for turbid water; and potential hazards to users. Additional information on electrofishing can. open, fire-maintained pine forests (Thompson, 1982). Survey methods for this species rely on identification of appropriate habitat (old-growth pine forest) and nest trees within the habitat (large-diameter