Applied Wetlands Science - Chapter 8 pptx

KentProperties of SoilHydrologic and Hydraulic PropertiesAquatic Physical and Chemical PropertiesOrganismal Properties Properties of Individual Wildlife and Fish SpeciesProperties of Wil

Kent, Donald M “Monitoring Wetlands”

Applied Wetlands Science and Technology

Editor Donald M Kent

Boca Raton: CRC Press LLC,2001

CHAPTER 8 Monitoring WetlandsDonald M Kent

Properties of SoilHydrologic and Hydraulic PropertiesAquatic Physical and Chemical PropertiesOrganismal Properties

Properties of Individual Wildlife and Fish SpeciesProperties of Wildlife and Fish CommunitiesApproaches to Monitoring

Selecting a Monitoring ApproachInvestment and ReturnInvestment, Return, and AreaInvestment, Return, and TimeMeasures and Monitoring ApproachesInvestment, Measures, and AreaInvestment, Measures, and TimeMonitoring Design and AnalysisDesign

AnalysisReferences

Wetlands monitoring is the checking, watching, or tracking of wetlands for thepurpose of collecting and interpreting data, which is then used to record or controlthe wetland or processes affecting the wetland Not to be confused with wetlandsassessment or evaluation which is the valuation of wetlands, monitoring of wetlands

is a component of mitigation efforts (Kusler and Kentula, 1990; U.S Army Corps

of Engineers, 1989), the Environmental Protection Agency’s Environmental toring and Assessment Program (Paul et al., 1990; Leibowitz et al., 1991), and otherprograms designed to protect, conserve, and understand wetland resources (NewHampshire Water Pollution Control Commission, 1989; Haddad, 1990; Walker,1991) Monitoring efforts are conducted for several reasons using a variety oftechniques to measure and assess an array of structural and functional parameters.The process of developing and implementing a monitoring program can bereduced to four basic steps (Figure 1) First and foremost, the reason for monitoringmust be identified and clearly stated Second, a determination of the measuresappropriate for achieving the stated objective(s) must be made Third, an approachcommensurate with the level of investment and the required return must be selected.The size of the area to be monitored, as well as the length of time the area will bemonitored, will affect selection of an approach Finally, the information gatheredfrom the monitoring effort must be analyzed and interpreted

Moni-REASONS FOR MONITORING

For the most part, wetland monitoring is conducted for a relatively few, discretereasons Habitat mapping and trend analysis monitoring are conducted to identifywetlands resources and to detect changes in these resources over time Examples ofmapping and trend analysis monitoring include efforts in coastal and seaway Canada(Rump, 1987), coastal India (Nayak et al., 1989), migratory bird habitat in centralCalifornia (Peters, 1989), and the National Wetlands Inventory project (Dahl andPywell, 1989)

Perhaps the largest monitoring effort of this type is the Environmental Monitoringand Assessment Program (Paul et al., 1990; Liebowitz, 1991) The program, designed

to monitor the condition of wetlands, has stimulated mapping and trend analysismonitoring throughout the United States (Haddad, 1990; Johnston and Handley,1990; Orth et al., 1990) Initial aspects of the wetland ecosystems component of theEnvironmental Monitoring and Assessment Program focus on determining the sen-sitivity of various metrics for detecting known levels of stress and determining thespatial and temporal variability of proposed wetland indicators of condition (U.S.Environmental Protection Agency, 1990)

Wildlife and fisheries management monitoring is also a type of habitat mappingand trend analysis monitoring It is conducted to provide information about speciesrichness and species abundance over time and to assess the effects of managementstrategies The wildlife or fisheries population (Henny et al., 1972; Neilson andGreen, 1981; Hink and Ohmart, 1984; Young, 1987; Molini, 1989), habitat indicators

of wildlife richness and abundance (Weller and Fredrickson, 1974; Koeln et al.,1988), or both (Weller, 1979; Weller and Voigts, 1983) are monitored

A second reason for monitoring is to determine the effectiveness of enhancement,restoration, and creation efforts Examples include evaluation of habitat created usingdredge spoil (Newling and Landin, 1985; Landin et al., 1989) and restoration ofdegraded habitats (Pacific Estuarine Research Laboratory, 1990) There are numer-ous monitoring efforts associated with Section 404, state, and local wetland fillpermits (Kusler and Kentula, 1989; U.S Army Corps of Engineers, 1989; Erwin,1991) as well.

Impact analysis constitutes a third reason for monitoring Monitoring is ducted to determine the response of wetlands to identified direct and indirect impacts.Examples include monitoring of impacts to wetlands on and adjacent to hazardouswaste sites (Watson et al., 1985; Hebert et al., 1990), as well as impacts from discreteand continuous chemical contamination events (McFarlane and Watson, 1977;Woodward et al., 1988) Other examples of impact analysis monitoring includestudies of the effects of highway construction (Cramer and Hopkins, 1981), sitingimpacts from generating station construction and operation (Wynn and Kiefer, 1977),

con-Figure 1 Steps for developing and implementing a wetland monitoring program.

effects on wetland flora from exposure to electromagnetic fields (Guntenspergen

et al., 1989), and impacts from agricultural practices (Hawkins and Stewart, 1990;Walker, 1991)

Finally, wetlands may be monitored to determine the potential for, or ness of, wetlands for treating point source or nonpoint source discharges Treatmentmonitoring has been applied to studies of the effectiveness of constructed wetlandsfor domestic wastewater treatment (Hardy, 1988; Choate et al., 1990; TennesseeValley Authority, 1990), mine drainage (Eger and Kapakko, 1988; Stark et al., 1988;Stillings et al., 1988), stormwater runoff (Meiorin, 1991), and agricultural runoff(Costello, 1991)

effective-MEASURES

A large number of measures have been applied, or potentially can be applied,

to monitoring of wetland structure and function (Table 1) Commonly used measuresinclude measures of the properties of individual plants and animals, measures of theproperties of vegetation and wildlife communities, measures of aquatic physical andchemical properties, and measures of soil properties Less commonly used aremeasures of hydrologic and hydraulic properties such as flood frequency and ground-water depth Generally unused are potentially useful measures of landform propertiessuch as heterogeneity and patch characteristics (Forman and Godron, 1986) Thelatter properties are particularly important in the preservation and creation of wet-lands for wildlife and are likely to be useful for other aspects of habitat mappingand trend analysis monitoring Measures of organismal properties are typical ofimpact analysis monitoring programs

Properties of Individual Plants

Measures of the properties of individual plants are used to assess the condition

of natural plants and propagules In theory, the properties of a plant are affected byany factor that alters the growth and maintenance of the plant Factors that affectplant growth and maintenance include soil nutrients, soil moisture, disease, pestinfestations, and anthropogenic and other disturbances Information obtained frommeasurements of the properties of individual plants can be applied to trend analysismonitoring, enhanced, restored, and created wetlands monitoring, impact analysismonitoring, and treatment monitoring

The simplest measure of an individual plant is survival, that is, whether the plant

is dead or alive For living plants, measures include basal area, which is the area ofexposed stem if the plant were cut horizontally, and stem diameter, which is themaximum width of the area of exposed stem if the plant were cut horizontally Basalarea and stem diameter are usually measured in centimeters (2.5 cm equals 1 in.)above the ground by ecologists and range managers, and 1.4 m (4.5 ft) above theground by foresters Plant height is the mean vertical distance from the ground atthe base of a plant to the uppermost level of a plant Cover, including ground cover(herbaceous plants and low growing shrubs) and canopy cover (other shrubs and

trees), is that part of the ground area covered by the vertical projection downward

of the aerial part of the plant Typically, the vertical projection downward is viewed

as a polygon drawn around the plant’s perimeter and ignores small gaps betweenbranches Canopy diameter is the average maximum width of the polygon used forcanopy cover Basal area, stem diameter, plant height, cover, and canopy diameter,

if repeatedly measured over time, can be used as indicators of plant growth rate.Plants allocate net production to leaves, twigs, stem, bark, roots, flowers, andseeds The accumulated living organic matter is the biomass and is usually expressed

Table 1 Measures of Wetland Structure and Function

Properties of individual plants

Properties of vegetation communities

Density Landform properties

Isolation Properties of soil

Hydrologic and hydraulic properties

Aquatic physical/chemical properties

Nutrients Organismal properties

Properties of individual wildlife and fish species

Properties of wildlife communities

as the dry weight per unit of area Determining the allocation to each part is generallyinvasive in that the parts must be removed from the plant and either weighed oranalyzed for energy or nutrient content Nevertheless, individual plant productivitycan be estimated by sampling leaves, flowers, or seeds (Figure 2).

Properties of Vegetation Communities

Just as factors that affect plant growth and maintenance are reflected in surements of the properties of individual plants, factors which affect more than oneindividual plant will be reflected in measurements of the properties of vegetationcommunities Therefore, measures of the properties of vegetation communities are

mea-of use in assessing the condition mea-of natural and mitigated vegetation communities.Measures of the properties of vegetation communities include extensions ofthe measures applied to individual plants as well as measures which are unique

to the characterization of communities Measures of community survival, basal

Figure 2 Monitoring of individual plants during the appropriate season will indicate if

repro-duction is occurring Productivity can be estimated by sampling leaves, flowers,

or seeds.

cover, cover, and biomass require the accumulation of measures of individualplants The cumulative expression of these measures, relative to the number ofindividuals assessed in the case of survival, or relative to the size of the areaassessed in the case of basal cover and cover, provides for the description of thevegetation community.

Properties unique to vegetation communities include cover type, which is theassignment of the community or parts of the community, to predetermined categories(Figure 3) “Classification of wetlands and deepwater habitats of the United States”(Cowardin et al., 1979) is the most commonly used system for describing cover typeand its widespread use provides for comparison among disparate monitoring efforts.Nevertheless, the development of other descriptive systems is sometimes required

in order to maximize information return Other measures unique to the communitylevel are density, which describes the number of individuals per unit of area, andrichness, which is the list of plant species identified in the community of interest

If each individual plant within the sampling area is identified, then evenness can bedetermined Evenness describes how the species abundances are distributed amongthe species Another widely used measure of community structure, diversity, com-bines richness and evenness Because diversity measures combine richness andevenness, they confound the number of species, the relative abundances of thespecies, and the homogeneity and size of the area sampled, and are, therefore, lessuseful than measures of richness and evenness Finally, measures of stratification, adiversity index reflecting the amount of foliage at various levels above the ground,describe the vertical structure of the vegetation community

Figure 3 Wetlands can be monitored for cover type, which is the assignment of the plant

community, in this case emergent macrophytes, to predetermined categories.

Landform Properties

Measures of landform properties are used by landscape ecologists to identifyand describe individual communities and the relationships among communities Themeasures can be valuable to wetland scientists interested in local and regionalplanning issues, particularly because these issues relate to wildlife and trend analysis.However, the measures have been infrequently used and, therefore, require precisedefinition and identification of limitations, when applied

Some measures of landform properties, such as shape and size, can be applied

to studies of single wetlands Shape is typically described as a ratio of wetlandperimeter to wetland area (Bowen and Burgess, 1981) Size is described as the area

of the wetland or by some linear dimension such as length, width, or the ratio oflength to width

Other measures of landform properties require consideration of more than asingle wetland Accessibility describes the distance along a corridor of suitablehabitat from one wetland to another and reflects the perceived ease of speciesmovement (Bowen and Burgess, 1981) Dispersion describes the pattern (e.g.,clumped, uniform, random) of spatial arrangement among wetlands (Pielou, 1977).Isolation describes the distance of a wetland from other wetlands (Bowen andBurgess, 1981) and interaction describes the perceived influence of a wetland onanother wetland through consideration of the distance between wetlands(MacClintock et al., 1977)

Properties of Soil

Measures of the properties of soils are useful in describing wetland structureand provide clues to wetland function As part of mapping and trend analysismonitoring efforts, measures of soil properties help to distinguish between wetlandand nonwetland areas and provide information as to changes to these areas Ifmonitored as part of a wetland enhancement, restoration, or creation effort, includingefforts associated with the establishment of treatment wetlands, measures of theproperties of soil indicate the development of hydric conditions

Soil is typically classified according to such characters as color, texture, and sizeand shape of aggregates The Department of Agriculture Soil Conservation Servicesystem is the commonly used taxonomic classification system in the United States.Based upon the kind and character of soil properties and the arrangement of horizonswithin the profile, the system also provides information about the use and manage-ment of the soil Soil texture is based on the relative proportions of the various soilseparates in a sample and is estimated from its plasticity when extruded and byfeeling its grittiness (Hays et al., 1981) Soil moisture is the percent of a givenamount of soil consisting of water and is estimated by the loss of weight on drying.Soil organic content is the percent of a given amount of soil consisting of organicmatter and is estimated by loss of weight upon ignition

Hydrologic and Hydraulic Properties

Simply stated, a wetland is a wetland because it is wet Hydrologic and hydraulicmeasures provide useful descriptors of wetland structure and also provide valuableinformation as to wetland function Measures of hydrologic and hydraulic propertiesprovide information about the extent of wetlands as well as the effect of intrinsicand extrinsic changes to wetlands Treatment monitoring benefits from measures ofhydrologic and hydraulic properties in determining maximum treatment capacity.Measures of hydrologic and hydraulic properties as part of enhanced, restored, andcreated wetland efforts are integral to an assessment of project success

Velocity describes the speed at which water travels and reflects not only thedepth and width of the water body, but also the topographical gradient and theextent and type of vegetation Water depth, width, and area are descriptors ofwetland structure Monitored over time, and in relation to extreme events, thesemeasures provide an empirical estimate of the frequency of flooding and of floodstorage volume Flood storage volume can also be estimated using one of a number

of computerized hydrological models (U.S Army Corps of Engineers, 1981; SoilConservation Service Hydrology Units 1982 and 1986; Huber and Dickinson,1988) Model inputs include wetland and watershed slope, vegetative cover, soiltype, and surface type (i.e., pervious or impervious) Groundwater depth, thedistance below the ground surface at which water occurs, can be determinedempirically through the installation and monitoring of wells (Figure 4) Ground-water recharge volume, the volume of surface water moving down through the soil

to an underlying groundwater system or aquifer, can be estimated using the mentioned hydrological models

afore-Aquatic Physical and Chemical Properties

The quality of water affects the growth, maintenance, and reproduction of land flora and fauna Wetland water quality is revealed by measures of aquaticphysical and chemical properties Water quality reflects the condition of the sur-rounding environment and is affected by human activities such as watershed erosionand point and nonpoint source discharges Wetland water quality also reflects thecondition of the wetland itself Measures of aquatic physical and chemical propertiesare particularly applicable to monitoring of the effects of impacts to wetlands andmonitoring the effectiveness of treatment wetlands

wet-Water temperature influences the rate of metabolic reactions, the reactivity ofenzymes, and the amount of oxygen that can be dissolved in water The pH of wateraffects organismal physiological reactions and membrane characteristics Dissolvedoxygen concentrations must be sufficient to enable diffusion from the water into ananimal’s blood Salinity affects water quality through its effect on the ability ofspecies to maintain osmotic balance Turbidity restricts the depth to which solarradiation can penetrate the water column Dissolved solids, such as carbonates,bicarbonates, chlorides, phosphates, nitrates, and salts of calcium, magnesium,sodium, and potassium, affect organismal ionic balance and other physiologicalprocesses Biological oxygen demand, the amount of oxygen required by bacteria

while stabilizing decomposable organic matter under aerobic conditions, reflects thetrophic status of the aquatic body and possibly the extent and type of inputs to theaquatic body Trophic status is also revealed by measures of chlorophyll and ofnutrients such as nitrates, nitrites, and phosphates Measures of toxicants such asheavy metals, volatile organic compounds, and petroleum hydrocarbons provide adirect measure of contaminants.

Organismal Properties

As with plants, factors that alter the growth, reproduction, and maintenance of

an individual organism will affect the properties of that organism Therefore, thoseproperties will be of use in assessing the condition of that organism Factors thataffect organismal growth, reproduction, and maintenance include water quality,including the presence or absence of environmental toxins, and the availability offood and cover Measures of the properties of individual organisms are of particularuse in monitoring impacted wetlands or in assessing the affects to a natural wetlandused for treatment of a discharge

Organismal behavior, such as predator avoidance, foraging effectiveness, andintraspecific social interactions, is modified by factors that affect the wetland So,too, the rate or age of the onset of reproduction and the rate of growth and develop-ment are similarly affected Factors may also affect organismal metabolism, such asoxygen consumption, photosynthesis, nutrient uptake, or enzymatic reactivity In amore direct sense, organisms express a response to unfavorable environmental factors

by the bioaccumulation of chemical constituents In some cases, bioaccumulated

Figure 4 Groundwater depth, the distance below the ground surface at which water occurs,

can be monitored empirically using wells.

chemical constituents are evidenced by changes in tissue health, such as lesions andtumors.

Properties of Individual Wildlife and Fish Species

Factors that grossly affect organisms, particularly those factors that affect duction and growth and development, will be reflected in properties of individualwildlife and fish populations Therefore, measures of the properties of individualwildlife and fish species are of use in monitoring impacted wetlands These measuresare also useful for trend analysis monitoring efforts in that they reflect the condition

repro-of the wetland relative to the focal species Finally, measures repro-of the properties repro-ofindividual wildlife and fish species provide important information as to the value ofenhanced, restored, and created wetlands as wildlife or fisheries habitat

The simplest measures of individual wildlife and fish species are ence/absence and abundance (Figure 5) Requiring relatively more effort are mea-sures of population density, the number of individuals per unit of area Othermeasures are useful in assessing the potential persistence of the species Mortalitycan be expressed as either the probability of dying or as the death rate The com-plement of mortality is survival, the probability of living Natality is the production

pres-of new individuals in the population and can be described as the maximum orphysiological natality or as the realized mortality Changes in mortality, survival,and natality are reflected in the age structure of the wildlife or fish population.Declining or stabilized populations are characterized by relatively fewer young inthe reproductive age classes and a relatively larger proportion of individuals in olderage classes Conversely, growing populations are characterized by a relatively largerproportion of the younger age classes Monitoring efforts interested in determininghow a wildlife or fish species is distributed throughout the wetland will use measures

of association

Properties of Wildlife and Fish Communities

Analogous to the situation with vegetation communities, factors which affect thereproduction, growth, and development of more than one wildlife or fish specieswill be reflected in measurements of the properties of wildlife and fish communities

As with measures of the properties of individual wildlife and fish species, measures

of the properties of wildlife and fish communities are applicable to impact ing, trend analysis monitoring, and enhanced, restored, and created wetlands mon-itoring efforts

monitor-Measures of wildlife or fish community abundance and density provide grossestimates of wetland condition and suitability (Figure 6) The number of speciesoccurring in the community is the richness Evenness refers to how the speciesabundances are distributed among the species The richness and evenness measuresare frequently combined to form a single measure of diversity Again, the majorcriticism of diversity measures is that they confound a number of variables thatcharacterize community structure (Ludwig and Reynolds, 1988) Alternatively, bio-mass can be used to quantitatively describe wildlife and fish communities More

commonly applied to measures of vegetation communities, biomass is of use indescribing community structure, particularly energy flow Monitoring efforts inter-ested in determining how coexisting species use common wetland resources willuse measures of niche overlap.

APPROACHES TO MONITORING

Two broad approaches are available for monitoring wetlands: remote and contact.Remote monitoring is the acquisition of information about a wetland from a distance,without physical contact Conversely, contact monitoring is the acquisition of infor-mation about a wetland from near at hand, with physical contact

Remote monitoring of wetlands provides a level of spatial and temporal samplingthat is impractical with contact techniques Because data are available at large andsynoptic scales, large-scale patterns can be discerned and large-scale processes can

be measured Space-based remote sensing instruments measure electromagnetic ation reflected and emitted by the earth’s surface Visible and thermal satellite dataprovide location information about broad vegetation cover types and extent of inun-dation (Carter et al., 1976; Roughgarden et al., 1991; Wickland, 1991) Comparison

radi-of images along a temporal gradient provides information about land use and tation successional changes (Mackey and Jensen, 1989; Nayak et al., 1989; Byrneand Dabrowska-Zielinska, 1981) Information is provided at mesoscale, macroscale,

vege-Figure 5 Wildlife presence/absence and abundance can reasonably be monitored with a

minimum of effort.