US Long-Term Ecological Research Network

North Temperate Lakes LTER Regional Survey Macrophytes Plant Index 2015 - current

Abstract
The Northern Highlands Lake District (NHLD) is one of the few regions in the world with periodic comprehensive water chemistry data from hundreds of lakes spanning almost a century. Birge and Juday directed the first comprehensive assessment of water chemistry in the NHLD, sampling more than 600 lakes in the 1920s and 30s. These surveys have been repeated by various agencies and we now have data from the 1920s (UW), 1960s (WDNR), 1970s (EPA), 1980s (EPA), 1990s (EPA), and 2000s (NTL). The 28 lakes sampled as part of the Regional Lake Survey have been sampled by at least four of these regional surveys including the 1920s Birge and Juday sampling efforts. These 28 lakes were selected to represent a gradient of landscape position and shoreline development, both of which are important factors influencing social and ecological dynamics of lakes in the NHLD. This long-term regional dataset will lead to a greater understanding of whether and how large-scale drivers such as climate change and variability, lakeshore residential development, introductions of invasive species, or forest management have altered regional water chemistry. The purpose of the macrophyte survey is to identify, and quantify the types of aquatic plants within the various 28 regional survey lakes. The macrophyte survey consists of sampling macrophyte plants using a metal rake attached to a 15ft pole at approximately 140 spatially resolved points on a lake that are spread out in a grid like fashion, equally spaced from each other. Sampling locations were chosen such that the maximum depth at which macrophytes were surveyed was equal to or less than 15ft of water. Macrophyte sampling occurs in the latter part of the summer (after July 10) to ensure that macrophytes have had adequate time to grow and our sampling efforts capture the typical summer macrophyte community in each lake. Macrophyte sampling in these 28 lakes is ongoing and will be repeated approximately once every six years.
Core Areas
Dataset ID
338
Date Range
-
Methods
the protocol employed here is based on:
Hauxwell, J., S. Knight, K. Wagner, A. Mikulyuk, M. Nault, M. Porzky and S. Chase . 2010. Recommended baseline monitoring of aquat ic plants in Wisconsin : sampling design, field and laboratory procedures, data entry and analys is, and applica tions. Wisconsin Department of Natural Resources Bureau of Science Services, PUB-SS-1068 2010. Madison, Wisconsin, USA.
Version Number
13

North Temperate Lakes LTER: Sparkling Lake Macrophytes 2001 - 2010

Abstract
Macrophyte cover in Sparkling Lake sampled in late July from 2001 to 2010 from the waterline to a depth of 4 meters.
Core Areas
Dataset ID
272
Date Range
-
LTER Keywords
Maintenance
completed
Metadata Provider
Methods
Macrophyte cover in Sparkling Lake was assessed in the third or fourth week of July from 2002-2004 and from 2007-2010. Eight transects were selected to correspond to trap survey sites for rusty crayfish and represent the range of macrophyte communities in the lake. These transects stretched from the waterline to a depth of 4 meters, running perpendicular to shore. Circular quadrats (1m2) were placed along each transect at 1 m longitudinal intervals, and observers using SCUBA estimated visually the percent cover of each macrophyte species within the quadrat. The sum of percent cover of all species within a quadrat does not necessarily add to 100; rather, this sum reflects the percentage of bottom substrate covered by macrophytes.
Version Number
22

North Temperate Lakes LTER: Macrophyte Species at Quadrat Level - Trout Lake 1993 - current

Abstract
These data are collected to document and characterize the submersed macrophytes of Trout Lake, to evaluate the long-term stability of this component, and to interface with investigations of other compartments of the ecosystem. Four sites along the shoreline of Trout Lake have been sampled annually in August along permanent line transects. These are quadrat-species level data. This dataset only contains information on species that were present. It includes a row for every species-quadrat present. If a quadrat is missing, that quadrat was either empty or was not sampled. Sampling Frequency: annually during summer Number of sites: 4
Core Areas
Dataset ID
26
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
I Site Locations Sites are designated according to the LTER numbering scheme established for the shoreline of the south basin of Trout Lake and its islands (see fig. 1). The four sites used by the macrophyte component are also used in the LTER fish and crayfish sampling and the descriptions that follow make reference to the shore stakes set for the fish sampling crews. Appendix A details their placement. In addition, photos have been included to identify the landmarks used. Each site establishes a transect line from a proximal shore landmark to a distal shore landmark on a specified compass heading. Site 7 Rocky Reef Bay: Landmarks: Proximal - Large birch with a spike nailed one foot above the base. Also at fish sampling stake D. Distal - The Rocky Reef Resort main building located in line with the north end of Rocky Reef Island. Compass Heading: 280degree Site 31 Channel Mouth Island: Landmarks: Proximal - White Birch at fish sampling stake B Distal - A distant pine (approx. 1 mi.) standing above the canopy in the skyline facing east. Pine is at peak where the landscape shows a rise. Compass Heading: 83degree Site 50 - Southwest Bay of South Trout: Landmarks: Proximal - Large White Pine in clearing between fish sampling stake C and D. About 9 meters east of stake D. Distal - The west tip of Haunted Island. Compass Heading: 13degree Site 56 - Mouth of Mann Creek: Landmarks: Proximal - Large White Cedar with spike nailed 1 foot above base. Distal - The west tip of Millers Island. Compass Heading: 41degree. II Line Transects The site descriptions specify a transect line along which presenceorabsence data is recorded for all macrophyte species. A 0.25 M2 ring placed at 1 meter intervals (except site 7 - 0.5 to 1 M depth where the ring is placed at 2 meter intervals) along transect designates the sampling quadrat. Using SCUBA, species data are recorded along with the total number of quadrats encountered between the following depth intervals: 0.5-1 M, 1-2 M, 2-3 M and 3-5 M. These depth intervals have been permanently established with markers consisting of a commercial Earth Anchor set in the lake bottom with 2 floats secured to it near the bottom. Large boat bumpers are used on the anchors at 3 and 5 meters. The other floats are small polybottles. Between 28 and 52 quadrats are examined within each depth interval at each site. The paths over which the quadrats are laid are shown on the site maps (Figs. 2-5). A species list is given in appendix B. III Biomass Harvesting. Five replicate quadrats (0.25 M2) are harvested for all above ground biomass at each site at each of three nominal depths: 1.5 M, 2.5 M and 4 M. Samples are removed along a line parallel to shore - located midway between each of the 1, 2, 3 and 5 M anchors. Figures 2-5 show the distribution of the replicates. Four sites with 3 depths and 5 replicates yields 60 samples. A sample may be empty. In the lab, samples are separated by species, placed in labeled paper bags (LABEL: SpeciesorSiteorDepthorRepnumber ), oven dried, and weights recorded. Paper bags used for drying should be purchased in groups to allow the plant weights to be determined by difference using an average tare for a group of bags. Paper bags for determining average tare should be wetted and oven dried in the same manor as the bags containing plant samples. IV Additional Comments. A. Pre-1987 Data. In 1987, permanent line transects were established at each of the sites. Biomass samples and line transects observed before 1987 were set by more general descriptions at the site and were not identical year to year. B. Biomass Weights. Starting in 1989, biomass weights were determined by weighing dried plants in paper bags and using an average tare for the bags. Consequently, values in the data base can be negative and should be considered as present in very small amounts.
Short Name
NTLMP06
Version Number
24

North Temperate Lakes LTER: Macrophyte Richness - Trout Lake 1993 - current

Abstract
These data are collected to document and characterize the submersed macrophytes of Trout Lake, to evaluate the long-term stability of this component, and to interface with investigations of other compartments of the ecosystem. Four sites along the shoreline of Trout Lake have been sampled annually in August along permanent line transects. These data are quadrat level data. This dataset includes a row for every quadrat sampled. The RICHNESS field contains the number of species present (set to zero if the quadrat was empty). If a row is missing, that quadrat was not sampled Sampling Frequency: annually during summer Number of sites: 4
Dataset ID
28
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
I Site Locations Sites are designated according to the LTER numbering scheme established for the shoreline of the south basin of Trout Lake and its islands (see fig. 1). The four sites used by the macrophyte component are also used in the LTER fish and crayfish sampling and the descriptions that follow make reference to the shore stakes set for the fish sampling crews. Appendix A details their placement. In addition, photos have been included to identify the landmarks used. Each site establishes a transect line from a proximal shore landmark to a distal shore landmark on a specified compass heading. Site 7 Rocky Reef Bay: Landmarks: Proximal - Large birch with a spike nailed one foot above the base. Also at fish sampling stake D. Distal - The Rocky Reef Resort main building located in line with the north end of Rocky Reef Island. Compass Heading: 280degree Site 31 Channel Mouth Island: Landmarks: Proximal - White Birch at fish sampling stake B Distal - A distant pine (approx. 1 mi.) standing above the canopy in the skyline facing east. Pine is at peak where the landscape shows a rise. Compass Heading: 83degree Site 50 - Southwest Bay of South Trout: Landmarks: Proximal - Large White Pine in clearing between fish sampling stake C and D. About 9 meters east of stake D. Distal - The west tip of Haunted Island. Compass Heading: 13degree Site 56 - Mouth of Mann Creek: Landmarks: Proximal - Large White Cedar with spike nailed 1 foot above base. Distal - The west tip of Millers Island. Compass Heading: 41degree. II Line Transects The site descriptions specify a transect line along which presenceorabsence data is recorded for all macrophyte species. A 0.25 M2 ring placed at 1 meter intervals (except site 7 - 0.5 to 1 M depth where the ring is placed at 2 meter intervals) along transect designates the sampling quadrat. Using SCUBA, species data are recorded along with the total number of quadrats encountered between the following depth intervals: 0.5-1 M, 1-2 M, 2-3 M and 3-5 M. These depth intervals have been permanently established with markers consisting of a commercial Earth Anchor set in the lake bottom with 2 floats secured to it near the bottom. Large boat bumpers are used on the anchors at 3 and 5 meters. The other floats are small polybottles. Between 28 and 52 quadrats are examined within each depth interval at each site. The paths over which the quadrats are laid are shown on the site maps (Figs. 2-5). A species list is given in appendix B. III Biomass Harvesting. Five replicate quadrats (0.25 M2) are harvested for all above ground biomass at each site at each of three nominal depths: 1.5 M, 2.5 M and 4 M. Samples are removed along a line parallel to shore - located midway between each of the 1, 2, 3 and 5 M anchors. Figures 2-5 show the distribution of the replicates. Four sites with 3 depths and 5 replicates yields 60 samples. A sample may be empty. In the lab, samples are separated by species, placed in labeled paper bags (LABEL: SpeciesorSiteorDepthorRepnumber ), oven dried, and weights recorded. Paper bags used for drying should be purchased in groups to allow the plant weights to be determined by difference using an average tare for a group of bags. Paper bags for determining average tare should be wetted and oven dried in the same manor as the bags containing plant samples. IV Additional Comments. A. Pre-1987 Data. In 1987, permanent line transects were established at each of the sites. Biomass samples and line transects observed before 1987 were set by more general descriptions at the site and were not identical year to year. B. Biomass Weights. Starting in 1989, biomass weights were determined by weighing dried plants in paper bags and using an average tare for the bags. Consequently, values in the data base can be negative and should be considered as present in very small amounts.
Short Name
NTLMP08
Version Number
24

North Temperate Lakes LTER: Macrophyte Transects - Trout Lake 1982 - current

Abstract
These data are collected to document and characterize the submersed macrophytes of Trout Lake to evaluate the long-term stability of this component and to interface with investigations of other compartments of the ecosystem. Four sites along the shoreline of Trout Lake have been sampled annually in August along permanent line transects. This dataset includes species presence/absence and transect summary data by depth along the transect. This information is useful in determining the annual variability of the submersed macrophytes and providing information on the effects of the invasion of an introduced crayfish Sampling Frequency: annually during summer Number of sites: 4
Dataset ID
22
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
I Site Locations Sites are designated according to the LTER numbering scheme established for the shoreline of the south basin of Trout Lake and its islands (see fig. 1). The four sites used by the macrophyte component are also used in the LTER fish and crayfish sampling and the descriptions that follow make reference to the shore stakes set for the fish sampling crews. Appendix A details their placement. In addition, photos have been included to identify the landmarks used. Each site establishes a transect line from a proximal shore landmark to a distal shore landmark on a specified compass heading. Site 7 Rocky Reef Bay: Landmarks: Proximal - Large birch with a spike nailed one foot above the base. Also at fish sampling stake D. Distal - The Rocky Reef Resort main building located in line with the north end of Rocky Reef Island. Compass Heading: 280degree Site 31 Channel Mouth Island: Landmarks: Proximal - White Birch at fish sampling stake B Distal - A distant pine (approx. 1 mi.) standing above the canopy in the skyline facing east. Pine is at peak where the landscape shows a rise. Compass Heading: 83degree Site 50 - Southwest Bay of South Trout: Landmarks: Proximal - Large White Pine in clearing between fish sampling stake C and D. About 9 meters east of stake D. Distal - The west tip of Haunted Island. Compass Heading: 13degree Site 56 - Mouth of Mann Creek: Landmarks: Proximal - Large White Cedar with spike nailed 1 foot above base. Distal - The west tip of Millers Island. Compass Heading: 41degree. II Line Transects The site descriptions specify a transect line along which presenceorabsence data is recorded for all macrophyte species. A 0.25 M2 ring placed at 1 meter intervals (except site 7 - 0.5 to 1 M depth where the ring is placed at 2 meter intervals) along transect designates the sampling quadrat. Using SCUBA, species data are recorded along with the total number of quadrats encountered between the following depth intervals: 0.5-1 M, 1-2 M, 2-3 M and 3-5 M. These depth intervals have been permanently established with markers consisting of a commercial Earth Anchor set in the lake bottom with 2 floats secured to it near the bottom. Large boat bumpers are used on the anchors at 3 and 5 meters. The other floats are small polybottles. Between 28 and 52 quadrats are examined within each depth interval at each site. The paths over which the quadrats are laid are shown on the site maps (Figs. 2-5). A species list is given in appendix B. III Biomass Harvesting. Five replicate quadrats (0.25 M2) are harvested for all above ground biomass at each site at each of three nominal depths: 1.5 M, 2.5 M and 4 M. Samples are removed along a line parallel to shore - located midway between each of the 1, 2, 3 and 5 M anchors. Figures 2-5 show the distribution of the replicates. Four sites with 3 depths and 5 replicates yields 60 samples. A sample may be empty. In the lab, samples are separated by species, placed in labeled paper bags (LABEL: SpeciesorSiteorDepthorRepnumber ), oven dried, and weights recorded. Paper bags used for drying should be purchased in groups to allow the plant weights to be determined by difference using an average tare for a group of bags. Paper bags for determining average tare should be wetted and oven dried in the same manor as the bags containing plant samples. IV Additional Comments. A. Pre-1987 Data. In 1987, permanent line transects were established at each of the sites. Biomass samples and line transects observed before 1987 were set by more general descriptions at the site and were not identical year to year. B. Biomass Weights. Starting in 1989, biomass weights were determined by weighing dried plants in paper bags and using an average tare for the bags. Consequently, values in the data base can be negative and should be considered as present in very small amounts.
Short Name
NTLMP02
Version Number
47

North Temperate Lakes LTER: Macrophyte Biomass in Trout Lake Summary 1983 - current

Abstract
These data are collected to document and characterize the submersed macrophytes of Trout Lake, to evaluate the long-term stability of this component, and to interface with investigations of other compartments of the ecosystem. Four sites along the shoreline of Trout Lake have been sampled annually in August along permanent line transects. This dataset includes biomass per m2 for individual species summarized by depth along the transect. Derived data include the mean and standard deviation of macrophyte biomass. These data are useful in determining the annual variability of the submersed macrophytes and providing information on the effects of the invasion of an introduced crayfish. Sampling Frequency: annually during summer Number of sites: 4
Core Areas
Dataset ID
25
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
I Site Locations Sites are designated according to the LTER numbering scheme established for the shoreline of the south basin of Trout Lake and its islands (see fig. 1). The four sites used by the macrophyte component are also used in the LTER fish and crayfish sampling and the descriptions that follow make reference to the shore stakes set for the fish sampling crews. Appendix A details their placement. In addition, photos have been included to identify the landmarks used. Each site establishes a transect line from a proximal shore landmark to a distal shore landmark on a specified compass heading. Site 7 Rocky Reef Bay: Landmarks: Proximal - Large birch with a spike nailed one foot above the base. Also at fish sampling stake D. Distal - The Rocky Reef Resort main building located in line with the north end of Rocky Reef Island. Compass Heading: 280degree Site 31 Channel Mouth Island: Landmarks: Proximal - White Birch at fish sampling stake B Distal - A distant pine (approx. 1 mi.) standing above the canopy in the skyline facing east. Pine is at peak where the landscape shows a rise. Compass Heading: 83degree Site 50 - Southwest Bay of South Trout: Landmarks: Proximal - Large White Pine in clearing between fish sampling stake C and D. About 9 meters east of stake D. Distal - The west tip of Haunted Island. Compass Heading: 13degree Site 56 - Mouth of Mann Creek: Landmarks: Proximal - Large White Cedar with spike nailed 1 foot above base. Distal - The west tip of Millers Island. Compass Heading: 41degree. II Line Transects The site descriptions specify a transect line along which presenceorabsence data is recorded for all macrophyte species. A 0.25 M2 ring placed at 1 meter intervals (except site 7 - 0.5 to 1 M depth where the ring is placed at 2 meter intervals) along transect designates the sampling quadrat. Using SCUBA, species data are recorded along with the total number of quadrats encountered between the following depth intervals: 0.5-1 M, 1-2 M, 2-3 M and 3-5 M. These depth intervals have been permanently established with markers consisting of a commercial Earth Anchor set in the lake bottom with 2 floats secured to it near the bottom. Large boat bumpers are used on the anchors at 3 and 5 meters. The other floats are small polybottles. Between 28 and 52 quadrats are examined within each depth interval at each site. The paths over which the quadrats are laid are shown on the site maps (Figs. 2-5). A species list is given in appendix B. III Biomass Harvesting. Five replicate quadrats (0.25 M2) are harvested for all above ground biomass at each site at each of three nominal depths: 1.5 M, 2.5 M and 4 M. Samples are removed along a line parallel to shore - located midway between each of the 1, 2, 3 and 5 M anchors. Figures 2-5 show the distribution of the replicates. Four sites with 3 depths and 5 replicates yields 60 samples. A sample may be empty. In the lab, samples are separated by species, placed in labeled paper bags (LABEL: SpeciesorSiteorDepthorRepnumber ), oven dried, and weights recorded. Paper bags used for drying should be purchased in groups to allow the plant weights to be determined by difference using an average tare for a group of bags. Paper bags for determining average tare should be wetted and oven dried in the same manor as the bags containing plant samples. IV Additional Comments. A. Pre-1987 Data. In 1987, permanent line transects were established at each of the sites. Biomass samples and line transects observed before 1987 were set by more general descriptions at the site and were not identical year to year. B. Biomass Weights. Starting in 1989, biomass weights were determined by weighing dried plants in paper bags and using an average tare for the bags. Consequently, values in the data base can be negative and should be considered as present in very small amounts.
Short Name
NTLMP05
Version Number
25

North Temperate Lakes LTER: Macrophyte Biomass - Madison Lakes Area 1995 - current

Abstract
Aquatic macrophytes are sampled from a boat at stations located at depths from 1 to 4 meters at 0.5-m intervals along transects perpendicular to the lake shoreline of the four primary study lakes in the Madison area (Lakes Mendota, Monona, and Wingra, and Fish Lake) from June to August. A weighted, double-headed garden rake is cast off the front left, front right, rear left, and rear right of the boat and then dragged approximately 2 meters across the bottom by means of an attached line. For each rake cast, the total amount of filamentous algae and aquatic macrophyte species present is assigned a density rating from 0-5 based on the extent of coverage of the upper rake head. Determination of extent of coverage involves judgment of the surveyor as to the number of rake teeth and area of teeth covered. Ratings from the 4 rake casts at each station can be averaged to compute an overall density rating for the station In addition, the total plant mass and the total filamentous algae mass in each tow is measured. To the maximum extent possible, water is squeezed from the plants to minimize the amount of water present in the final weight. Weights are recorded in the boat using field scales. Weights from the 4 rake casts at each station can be averaged to compute overall average weights for plant mass and for filamentous algae mass at the station. A related data set (Macrophyte Rating --- Madison Lakes Area), contains rake ratings for individual macrophyte species. For each rake cast, filamentous algae and any aquatic macrophyte species present are assigned a density rating from 0-5 based on the extent of coverage of the upper rake head. Determination of extent of coverage involves judgment of the surveyor as to the number of rake teeth and area of teeth covered by each species. It is necessary to separate plants to assess individual species coverage. Ratings from the 4 rake casts at each station can be averaged to compute an overall density rating for each species found at the station. Sampling Frequency: annually during summer Number of sites: 4
Core Areas
Dataset ID
24
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
Macrophyte Sampling Schedule 1. Macrophytes are sampled on Lakes Mendota, Monona, Waubesa, Wingra, and Fish Lake. Follow past years sampling order (Waubesa, Wingra, Fish, Monona, Mendota) and keep the dates as consistent to past years as possible (see list of dates). Working around the routine LTER sampling, schedule the macrophyte sampling well in advance in order to sign out a vehicle and boat when necessary. Macrophyte Sampling Method 1. Using the site book and the depth measuring pole, move to the 1 meter depth mark and throw both anchors. It seems easiest to first throw the anchor opposite the direction the boat is moving and throw the second anchor in the opposite direction after the line from the first anchor is taught. 2. From the Macrophyte Depth Table, find the distance to throw out the rake and hold that mark in one hand. Also determine the meter mark that the line should be drawn to. The table is calculated to determine the starting and ending meter marks to draw in the line to allow the rake to drag 2 meters on the lake bottom. The table assumes that the line is held 1meter above the water surface while dragging in the line. 3. Throw the rake horizontally out the side of the boat stopping it at the correct meter mark on the line. Allow the rake to sink to the bottom. Draw in the line, holding it approximately 1 meter above the water surface. Stop drawing in the line at the correct meter mark. 4. Pull the rake quickly out of the water. In order to retain the plants that are attached to the rake, it may be beneficial to rotate the rake 180 degrees once the rake handle is grabbed (so that the prongs that were dragged along the bottom are facing up). Then pivot the rake against the side of the boat and bring it into the boat. 5. Before removing the plant material from the rake, drape the long strands over the rake and gently push the plant material down on the rake. Assign a rake rating (from 1 to 5) depending on how much the plant material covers the rake prongs. The rake prongs are painted in 20percent increments. If the plant material only covers the lowest 20percent of the rake prongs, assign the rake rating a 1. If the plant material covers between 20percent and 40percent of the rake prongs, the rake rating is a 2, and so on (see page on rating description). 6. If a significant amount of dirt has been brought up with the plants (i.e. the weight of the dirt will add significantly to the total weight), wash the plants. Depending on the volume of the plants, wash them either by keeping them in your hands and dunking them in the lake or by putting them in the white bucket with the drain holes. 7. Separate the filamentous algae from the rest of the plant material. Separate and identify the individual plant species, throwing out any dead plant material. Give the filamentous algae and each plant species a rake rating (note that it is often necessary to visualize how much space each species would take up on the rake prongs rather than actually placing each species onto the rake). If a plant species can not be identified take a sample back to the lab by putting it in a ziplock bag with a small amount of water and temporarily storing it in a cooler. Temporarily assign each unknown species with a common symbol or name on the data sheet (to be changed to the correct species name when identified). Stan Nichols at the WGNHS can be used as a resource (263-7389). 8. Combine all of the plant species, keeping the filamentous algae separate, and squeeze out as much water as possible (it may be necessary to divide up the plant material into portions to effectively squeeze out the water). Weigh the plant material (minus the filamentous algae) and record the total weight. Weigh the filamentous algae and record the weight. 9. Repeat the above steps until 4 rake tosses have been thrown. Normally 2 rake tosses are thrown out each side of the boat to an area where the water depth is known to be at the desired depth. 10. Move to the next half-meter depth. Macrophytes are collected at each half-meter water depth from 1 meter to 4 meters. In the case of Lake Wingra, look at past years data to determine the deepest sampling depth for each transect (often 3 meters). In areas of steep drop-offs, it can be difficult to anchor the boat at the proper depth and it may be necessary to drop the anchor upwind and drift to the desired depth.
Short Name
NTLMP04
Version Number
27

North Temperate Lakes LTER: Macrophyte Rating - Madison Lakes Area 1995 - current

Abstract
Aquatic macrophytes are sampled from a boat at stations located at depths from 1 to 4 meters at 0.5-m intervals along transects perpendicular to the lake shoreline of the four primary study lakes in the Madison area (Lakes Mendota, Monona, and Wingra, and Fish Lake) from June to August. A weighted, double-headed garden rake is cast off the front left, front right, rear left, and rear right of the boat and then dragged approximately 2 meters across the bottom by means of an attached line. For each rake cast, filamentous algae and any aquatic macrophyte species present are assigned a density rating from 0-5 based on the extent of coverage of the upper rake head. Determination of extent of coverage involves judgment of the surveyor as to the number of rake teeth and area of teeth covered by each species. It is necessary to separate plants to assess individual species coverage. Ratings from the 4 rake casts at each station can be averaged to compute an overall density rating for each species found at the station.1 to 4 meters at 0.5-m intervals along transects perpendicular to the lake shoreline of the four primary study lakes in the Madison area (Lakes Mendota, Monona, and Wingra, and Fish Lake) from June to August. A weighted, double-headed garden rake is cast off the front left, front right, rear left, and rear right of the boat and then dragged approximately 2 meters across the bottom by means of an attached line. In addition (see related data set: Macrophyte Weight --- Madison Lakes Area), the total plant mass and the total filamentous algae mass in each tow is measured. To the maximum extent possible, water is squeezed from the plants to minimize the amount of water present in the final weight. Weights are recorded in the boat using field scales. Weights from the 4 rake casts at each station can be averaged to compute overall average weights for plant mass and for filamentous algae mass at the station. Sampling Frequency: annually during summer Number of sites: 4
Dataset ID
23
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
Macrophyte Sampling Schedule 1. Macrophytes are sampled on Lakes Mendota, Monona, Waubesa, Wingra, and Fish Lake. Follow past years sampling order (Waubesa, Wingra, Fish, Monona, Mendota) and keep the dates as consistent to past years as possible (see list of dates). Working around the routine LTER sampling, schedule the macrophyte sampling well in advance in order to sign out a vehicle and boat when necessary. Macrophyte Sampling Method 1. Using the site book and the depth measuring pole, move to the 1 meter depth mark and throw both anchors. It seems easiest to first throw the anchor opposite the direction the boat is moving and throw the second anchor in the opposite direction after the line from the first anchor is taught. 2. From the Macrophyte Depth Table, find the distance to throw out the rake and hold that mark in one hand. Also determine the meter mark that the line should be drawn to. The table is calculated to determine the starting and ending meter marks to draw in the line to allow the rake to drag 2 meters on the lake bottom. The table assumes that the line is held 1meter above the water surface while dragging in the line. 3. Throw the rake horizontally out the side of the boat stopping it at the correct meter mark on the line. Allow the rake to sink to the bottom. Draw in the line, holding it approximately 1 meter above the water surface. Stop drawing in the line at the correct meter mark. 4. Pull the rake quickly out of the water. In order to retain the plants that are attached to the rake, it may be beneficial to rotate the rake 180 degrees once the rake handle is grabbed (so that the prongs that were dragged along the bottom are facing up). Then pivot the rake against the side of the boat and bring it into the boat. 5. Before removing the plant material from the rake, drape the long strands over the rake and gently push the plant material down on the rake. Assign a rake rating (from 1 to 5) depending on how much the plant material covers the rake prongs. The rake prongs are painted in 20percent increments. If the plant material only covers the lowest 20percent of the rake prongs, assign the rake rating a 1. If the plant material covers between 20percent and 40percent of the rake prongs, the rake rating is a 2, and so on (see page on rating description). 6. If a significant amount of dirt has been brought up with the plants (i.e. the weight of the dirt will add significantly to the total weight), wash the plants. Depending on the volume of the plants, wash them either by keeping them in your hands and dunking them in the lake or by putting them in the white bucket with the drain holes. 7. Separate the filamentous algae from the rest of the plant material. Separate and identify the individual plant species, throwing out any dead plant material. Give the filamentous algae and each plant species a rake rating (note that it is often necessary to visualize how much space each species would take up on the rake prongs rather than actually placing each species onto the rake). If a plant species can not be identified take a sample back to the lab by putting it in a ziplock bag with a small amount of water and temporarily storing it in a cooler. Temporarily assign each unknown species with a common symbol or name on the data sheet (to be changed to the correct species name when identified). Stan Nichols at the WGNHS can be used as a resource (263-7389). 8. Combine all of the plant species, keeping the filamentous algae separate, and squeeze out as much water as possible (it may be necessary to divide up the plant material into portions to effectively squeeze out the water). Weigh the plant material (minus the filamentous algae) and record the total weight. Weigh the filamentous algae and record the weight. 9. Repeat the above steps until 4 rake tosses have been thrown. Normally 2 rake tosses are thrown out each side of the boat to an area where the water depth is known to be at the desired depth. 10. Move to the next half-meter depth. Macrophytes are collected at each half-meter water depth from 1 meter to 4 meters. In the case of Lake Wingra, look at past years data to determine the deepest sampling depth for each transect (often 3 meters). In areas of steep drop-offs, it can be difficult to anchor the boat at the proper depth and it may be necessary to drop the anchor upwind and drift to the desired depth.
Short Name
NTLMP03
Version Number
29
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