US Long-Term Ecological Research Network

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
Sites are designated according to the NTL numbering scheme established for the shoreline of the south basin of Trout Lake and its islands. The four sites (Trout-07, 46.01809769, -89.65571661; Trout-31, 46.0430698, -89.67157974; Trout-50, 46.01729465, -89.69461296; Trout-56, 46.01921135, -89.6813004) used by the macrophyte component are also used in the NTL fish and crayfish sampling. The site descriptions specify a transect line along which presence or absence 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 the 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. Between 28 and 52 quadrats are examined within each depth interval at each site.
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.
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
Sites are designated according to the NTL numbering scheme established for the shoreline of the south basin of Trout Lake and its islands. The four sites (Trout-07, 46.01809769, -89.65571661; Trout-31, 46.0430698, -89.67157974; Trout-50, 46.01729465, -89.69461296; Trout-56, 46.01921135, -89.6813004) used by the macrophyte component are also used in the NTL fish and crayfish sampling. The site descriptions specify a transect line along which presence or absence 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 the 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. Between 28 and 52 quadrats are examined within each depth interval at each site.
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.
Publication Date
Short Name
NTLMP02
Version Number
47

North Temperate Lakes LTER: Pelagic Macroinvertebrate Summary 1983 - current

Abstract
This is a summary of dataset NTL 13. Derived data include the mean and standard deviation of the number of each species captured as well as the mean and standard deviation of the density of individuals on both an areal and volumetric basis.
Five vertical tows are collected after dark at the deepest point of each of the seven primary lakes in the Trout Lake area (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes and bog lakes 27-02 [Crystal Bog], and 12-15 [Trout Bog]) using a 1-m diameter, 1-mm mesh net. On Trout Lake four additional sites are sampled, where depths are approximately at 10 m, 15 m, 20 m, and 25 m, with three tows taken at each site. Samples are preserved, and later counted in their entirety for Chaoborus spp., Leptodora kindtii, Mysis relicta, and Bythotrephes longimanus. Sampling Frequency: annually. Number of sites: 11
Core Areas
Dataset ID
14
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
Summary values are calculated from the number of individuals counted in each tow sample, diameter of net mouth, and depth of vertical tow.
Short Name
NTLIP02
Version Number
33

North Temperate Lakes LTER Pelagic Macroinvertebrate Abundance 1983 - current

Abstract
Pelagic macroinvertebrates are collected at night from the deepest location of each of the seven primary lakes in the Trout Lake area (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes and bog lakes 27-02 [Crystal Bog], and 12-15 [Trout Bog]) by vertical tow with a 1-m diameter, 1-mm mesh net. On Trout Lake four additional sites are sampled, where depths are approximately 10m, 15m, 20m, and 25m. Sampling is once per year in the summer, with replicate tows collected on each lake. These tows target the large invertebrate planktivore component of the pelagic zooplankton community. This data set contains the number of individuals in each tow sample of four taxonomic groups: Chaoborus spp. (differentiating between larvae and pupae), Leptodora kindtii, Mysis relicta, and Bythotrephes longimanus. Trout Lake was the only lake sampled in 2020. Sampling Frequency: annually. Number of sites: 11
Core Areas
Dataset ID
13
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
Vertical tows are collected after dark with a 1-meter diameter, 1-mm mesh net, with each lake sampled once between mid July and early August. Sampling stations are at the deepest location in each lake, with Trout Lake having four additional sampling stations at depths of 10m, 15m, 20m, and 25m. Five replicate tows are collected at the deep stations, and three replicate tows from each of the additional Trout Lake stations. Samples are preserved, and later counted in their entirety for Chaoborus spp. (differentiating between larvae and pupae), Leptodora kindtii, Mysis relicta, and Bythotrephes longimanus. One tow from each lake/station is archived in the UW Zoology museum.
Short Name
NTLIP01
Version Number
33

North Temperate Lakes LTER: Fish Species Richness 1981 - current

Abstract
This data set is a derived data set based on fish catch data. Data are collected annually to enable us to track the fish assemblages of eleven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, Trout, bog lakes 27-02 [Crystal Bog] and 12-15 [Trout Bog], Mendota, Monona, Wingra and Fish). Sampling on Lakes Monona, Wingra, and Fish started in 1995; sampling on other lakes started in 1981. Sampling is done at six littoral zone sites per lake with seine, minnow or crayfish traps, and fyke nets; a boat-mounted electrofishing system samples three littoral transects. Vertically hung gill nets are used to obtain two pelagic samples per lake from the deepest point. A trammel net samples across the thermocline at two sites per lake. In the bog lakes only fyke nets and minnow traps are deployed. Parameters measured include species-level identification and lengths for all fish caught, and weight and scale samples from a subset. Derived data sets include species richness, catch per unit effort, and size distribution by species, lake, and year. Species richness for a lake is the number of fish species caught in that lake during the annual fish sampling. Hybrids captured are only included in the richness value if neither of the two hybridized species are caught in the lake that year. Fish identified only to genus or higher taxonomic level are not included if any fish identified to species within that genus or higher taxonomic level are caught. E.g., Unidentified Chub would be only included in the richness value if no other chub is caught in that lake that year. Sampling Frequency: annually. Number of sites: 11
Note that 2020 data does not exist due to insufficient sampling. In 2021, sampling in Fish Lake was suspended due to significant lake level changes.
Core Areas
Dataset ID
245
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
The same sampling sites are used each year. All sampling occurs between the 3rd week of July and Labor Day. Sampling sites were chosen by random process in 1981 for the Northern lakes (Trout, Allequash, Sparkling, Crystal, and Big Muskellunge). Sites for Lake Mendota were chosen in 1981, and for the other Madison lakes (Monona, Fish, and Wingra) in 1995. All sites are identified with GPS coordinates, except on the bog lakes (Trout Bog and Crystal Bog) where nets are placed equal distances apart around the entire circumference of the lake in approximately the same locations each year.

Night seining is conducted on 6 seine sites per lake, each consisting of 100 meters of shoreline. Prior to 1997 this was subdivided into 3 seine hauls, each covering 33 meters. In 1997, seine hauls were reduced to 2 hauls of 33m each. The final section of the site is used as an alternate seine site in the event of difficulty in one of the first two hauls.
The seine used is 12.2 m long by 1.2 m deep, consisting of two 5.5 x 1.2 m wings surrounding a 1.2 x 1.2 x 1.2 m central bag. The wings are made of 6.4 mm stretch measure knitted delta-strength nylon mesh, and the bag is of 3.2 mm delta strength nylon mesh. The entire net is tarred. The two wings and the opening to the bag have weighted foot ropes and buoyed head ropes. An 8m length of rope is tied between the seine poles as a guide for the maximum spread of the seine.

A trammel net is set at two sites in each lake, and fished for approximately 24 hours at each site. The net is set on the bottom, along a line perpendicular to the shoreline and crossing the thermocline, with the shallow end at about 3m depth,. The trammel net used is 30.5 m long and 1.1 m deep. It consists of two outer nets of 170 mm square 32 kg test mesh multifilament nylon with an inner panel of 51 mm stretch mesh 9 kg test multifilament nylon. The three nets are connected at the leaded foot line and the buoyed head rope.

Fyke nets are deployed at six littoral sampling sites in each lake, and fished for approximately 24 hours. In Crystal Bog and Trout Bog lakes the fyke nets are suspended by placing floats on the hoops and frames to prevent the nets from sinking into the sediments. For the northern lakes, each fyke net is approximately 12 m long and consists of two rectangular steel frames 90 cm wide by 75 cm high and 4 steel hoops, all covered by 7 mm delta stretch mesh nylon netting. An 8 m long by 1.25 m deep leader net made of 7 mm delta stretch mesh nylon netting is attached to a center bar of the first rectangular frame (net mouth). The second rectangular frame has two 10 cm wide by 70 cm high openings, one on each side of the frame center bar. The four hoops follow the second frame. Throats 10 cm in diameter are located between the second and third hoops. The net ends in a bag with a 20.4 cm opening at the end, which is tied shut while the net is fishing. New nets of the same dimensions were purchased for the Northern Highland lakes in 2000. Fyke nets for the Madison lakes are 10 m long (including lead) with 1 rectangular aluminum frame followed by 2 aluminum hoops. The aluminum frame is 98 cm wide x 82 cm tall, and is constructed of 2.5 cm tubing, with an additional center vertical bar. The hoops are 60 cm in diameter and constructed of 5 mm diameter aluminum rod. The single net funnel is between the first and second hoops and is 20 cm in diameter. The lead is 8 m long and 1.25m deep, constructed from 7mm delta stretch mesh.

Crayfish traps are set on all lakes except the bog lakes (Crystal Bog and Trout Bog). Minnow traps are set only on the bog lakes. Prior to 1998, five traps were set at each fyke net site. Beginning 1998, three traps are set per site. Minnow traps and crayfish traps are set in shallow water (approx 1 m), 2 traps on one side, and 1 trap on the other side of the fyke net lead. Minnow traps are baited with 1 slice of bread, and crayfish traps with 120 g of beef liver. Traps are fished for approximately 24 hours. Crayfish are identified to species. Minnows caught in either crayfish or minnow traps are identified to species, and measured for total length. Minnow traps are galvanized steel two piece traps, 44.5 cm long by 30.5 cm maximum diameter with 2.5 cm diameter openings at the ends. The mesh size is 6.4 mm on a side. Crayfish traps are identical, but the opening hole of both sides of the trap has been forced to 5 to 7 cm. Crayfish sampling was terminated for the southern lakes in 2004 after it was determined that the catch per unit effort was too low (2 crayfish caught in 500+ traps)

Gill nets are set at the deepest point of all LTER lakes except Crystal Bog, Trout Bog, and Fish Lake. The nets are set for two consecutive 24 hour sets. The gill nets are a set of 7 nets, each in a different mesh size, hung vertically on foam rollers from the surface to the bottom of the lake, and chained together in a line. Each net is 4 m wide and 33 m long. From 1981 through 1990 the nets were multifilament mesh, in stretched mesh sizes of 19, 25, 32, 38, 51, 64, and 89 mm. In 1991, the multifilament nets were replaced with monofilament nets of the same sizes. Stretcher bars are installed at 10 meter intervals from the bottom to keep the net as rectangular as possible when deployed.

A boom style electrofishing system is used to sample the littoral zone fish community. Prior to 1997, four electrofishing transects were done on each lake. In 1997, the number of transects was reduced to 3. The same transects are used each year. Each transect consists of 30 minutes of current output, with the boat moving parallel to shore in 1-2 meters of water at a slow steady speed. We use the DC pulse system, with 240 volts at 3-5 amps. Transect lengths vary depending upon the size of the lake. If the end of a transect is reached before 30 minutes has elapsed, time is paused while the electrofisher loops back to the start of the transect. The transect is then repeated for the remaining time.

For all collecting methods, the fish are processed as follows. Each individual fish is identified to species. The total length of the fish is measured in mm, from nose to pinched tail. Prior to 1997, the weight of the first five fish of each species in each 10 mm size category was also measured, using Pesola spring balances. Starting in 1997, two fish are weighed for each species in each 5mm size category. A scale sample is collected from each yellow perch, rock bass, and cisco that is weighed. For gill net catches, the depth at which each individual is caught is also recorded.

Protocol Log. 1983: Discontinued fyke nets and trammel nets on Lake Mendota until 1995. 1984: Discontinued crayfish on Lake Mendota until 1995. Only gillnet and seines on Lake Mendota.1995: Resumed sampling Lake Mendota with the full suite of sampling gear. 1995: Began sampling Lakes Wingra, Monona, and Fish. 1997: Two fish are weighed for each fish species in each 5mm size category. Previously, five fish were weighed for each fish species in each 10mm size category. 1997: Data recording switched from manual field sheets to an electronic system. 1997: Changed from 4 to 3 electrofishing runs per lake. 1997: Changed from 18 to 12 seine hauls per lake. 1998: Changed from 30 to 18 crayfish or minnow traps per lake. 2004: Discontinued crayfish or minnow traps on southern lakes. 2020: Fish sampling very limited due to pandemic. 2021: Discontinued all night seining.
Short Name
NTLFI05
Version Number
25

North Temperate Lakes LTER: Benthic Macroinvertebrates 1981 - current

Abstract
Macroinvertebrates are collected from selected shoreline and deep water locations in the seven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes, and unnamed lakes 27-02 [Crystal Bog], and 12-15 [Trout Bog]) in the Trout Lake area using modified Hester-Dendy samplers. Samplers are placed at fyke net and gill net locations in August and retrieved 3-4 weeks later. Macroinvertebrates are preserved in ethanol. This dataset contains counts of various groups of macroinvertebrates identified from specific samples. The majority of the identifications are at the genus level. The data table "Benthic Macroinvertebrate Codes" identifies the taxonomic group represented by each group code. Taxonomic references: Ecology and Classification of North American Freshwater Invertebrates, Edited by James H Thorp and Alan P Covich, Academic Press, Inc, 1991; Aquatic Insects of Wisconsin, William L Hilsenhoff, Natural History Museums Council, University of Wisconsin-Madison (1995). Sampling Frequency: annually Number of sites: 7
Core Areas
Dataset ID
11
Date Range
-
Maintenance
Sampling continues, however, sample analysis happens only during specific projects. Samples are maintained in the zoological museum and can be checked out.
Metadata Provider
Methods
The modified Hester-Dendy samplers are constructed as a bolted together stack of ten plastic mesh panels and a plastic scrubbing ball between hardboard end panels. They are placed in the lakes early to mid August, and left for approximately four weeks. Each sampling site consists of three dendy samplers spaced 3 meters apart. Shoreline samplers are set in about one meter of water, deep sites at the deepest part of the lake. The shoreline sets are retrieved by a snorkeler who places the sampler in a container before surfacing to avoid loss of invertebrates due to disturbance, while deep sites are pulled up to the surface from a boat. Samplers are preserved in ethanol in the field, disassembled in the lab, and the invertebrates identified and counted under a dissecting microscope. All invertebrates are preserved in ethanol and archived in the UW Zoology museum. Samplers were set in all seven lakes in 1981-1989,1992 and 1993. Only Trout, Sparkling, and Crystal Lakes were sampled in 1990, 1991, and 1994 to present. No lakes were sampled in 2020.
Publication Date
Short Name
NTLIB01
Version Number
35

North Temperate Lakes LTER: Fish Abundance 1981 - current

Abstract
This data set is a derived data set based on fish catch data. Data are collected annually to enable us to track the fish assemblages of eleven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, Trout, bog lakes 27-02 [Crystal Bog] and 12-15 [Trout Bog], Mendota, Monona, Wingra and Fish). Sampling on Lakes Monona, Wingra, and Fish started in 1995; sampling on other lakes started in 1981. Sampling is done at six littoral zone sites per lake with seine, minnow or crayfish traps, and fyke nets; a boat-mounted electrofishing system samples three littoral transects. Vertically hung gill nets are used to obtain two pelagic samples per lake from the deepest point. A trammel net samples across the thermocline at two sites per lake. In the bog lakes only fyke nets and minnow traps are deployed. Parameters measured include species-level identification and lengths for all fish caught, and weight and scale samples from a subset. Derived data sets include species richness, catch per unit effort, and size distribution by species, lake, and year. Protocol used to generate data: Day seines were only used in 1981 and have been eliminated from this data set to make sampling effort across years comparable. Number caught for each species is summed over repetitions of a gear within a lake and over depth. For information on fish stocking by the Wisconsin Department of Natural Resources in LTER lakes in Dane and Vilas counties, see https://dnr.wi.gov/fisheriesmanagement/Public/Summary/Index The only sampling done in 2020 were a single gill-netting replicate in Sparkling, Crystal, and Trout lakes. Sampling in Fish Lake was suspended in 2021 due to significant lake level changes. Sampling Frequency: annually. Number of sites: 11
Core Areas
Dataset ID
7
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
The same sampling sites are used each year. All sampling occurs between the 3rd week of July and Labor Day. Sampling sites were chosen by random process in 1981 for the Northern lakes (Trout, Allequash, Sparkling, Crystal, and Big Muskellunge). Sites for Lake Mendota were chosen in 1981, and for the other Madison lakes (Monona, Fish, and Wingra) in 1995. All sites are identified with GPS coordinates, except on the bog lakes (Trout Bog and Crystal Bog) where nets are placed equal distances apart around the entire circumference of the lake in approximately the same locations each year.

Night seining is conducted on 6 seine sites per lake, each consisting of 100 meters of shoreline. Prior to 1997 this was subdivided into 3 seine hauls, each covering 33 meters. In 1997, seine hauls were reduced to 2 hauls of 33m each. The final section of the site is used as an alternate seine site in the event of difficulty in one of the first two hauls.
The seine used is 12.2 m long by 1.2 m deep, consisting of two 5.5 x 1.2 m wings surrounding a 1.2 x 1.2 x 1.2 m central bag. The wings are made of 6.4 mm stretch measure knitted delta-strength nylon mesh, and the bag is of 3.2 mm delta strength nylon mesh. The entire net is tarred. The two wings and the opening to the bag have weighted foot ropes and buoyed head ropes. An 8m length of rope is tied between the seine poles as a guide for the maximum spread of the seine.

A trammel net is set at two sites in each lake, and fished for approximately 24 hours at each site. The net is set on the bottom, along a line perpendicular to the shoreline and crossing the thermocline, with the shallow end at about 3m depth,. The trammel net used is 30.5 m long and 1.1 m deep. It consists of two outer nets of 170 mm square 32 kg test mesh multifilament nylon with an inner panel of 51 mm stretch mesh 9 kg test multifilament nylon. The three nets are connected at the leaded foot line and the buoyed head rope.

Fyke nets are deployed at six littoral sampling sites in each lake, and fished for approximately 24 hours. In Crystal Bog and Trout Bog lakes the fyke nets are suspended by placing floats on the hoops and frames to prevent the nets from sinking into the sediments. For the northern lakes, each fyke net is approximately 12 m long and consists of two rectangular steel frames 90 cm wide by 75 cm high and 4 steel hoops, all covered by 7 mm delta stretch mesh nylon netting. An 8 m long by 1.25 m deep leader net made of 7 mm delta stretch mesh nylon netting is attached to a center bar of the first rectangular frame (net mouth). The second rectangular frame has two 10 cm wide by 70 cm high openings, one on each side of the frame center bar. The four hoops follow the second frame. Throats 10 cm in diameter are located between the second and third hoops. The net ends in a bag with a 20.4 cm opening at the end, which is tied shut while the net is fishing. New nets of the same dimensions were purchased for the Northern Highland lakes in 2000. Fyke nets for the Madison lakes are 10 m long (including lead) with 1 rectangular aluminum frame followed by 2 aluminum hoops. The aluminum frame is 98 cm wide x 82 cm tall, and is constructed of 2.5 cm tubing, with an additional center vertical bar. The hoops are 60 cm in diameter and constructed of 5 mm diameter aluminum rod. The single net funnel is between the first and second hoops and is 20 cm in diameter. The lead is 8 m long and 1.25m deep, constructed from 7mm delta stretch mesh.

Crayfish traps are set on all lakes except the bog lakes (Crystal Bog and Trout Bog). Minnow traps are set only on the bog lakes. Prior to 1998, five traps were set at each fyke net site. Beginning 1998, three traps are set per site. Minnow traps and crayfish traps are set in shallow water (approx 1 m), 2 traps on one side, and 1 trap on the other side of the fyke net lead. Minnow traps are baited with 1 slice of bread, and crayfish traps with 120 g of beef liver. Traps are fished for approximately 24 hours. Crayfish are identified to species. Minnows caught in either crayfish or minnow traps are identified to species, and measured for total length. Minnow traps are galvanized steel two piece traps, 44.5 cm long by 30.5 cm maximum diameter with 2.5 cm diameter openings at the ends. The mesh size is 6.4 mm on a side. Crayfish traps are identical, but the opening hole of both sides of the trap has been forced to 5 to 7 cm. Crayfish sampling was terminated for the southern lakes in 2004 after it was determined that the catch per unit effort was too low (2 crayfish caught in 500+ traps)

Gill nets are set at the deepest point of all LTER lakes except Crystal Bog, Trout Bog, and Fish Lake. The nets are set for two consecutive 24 hour sets. The gill nets are a set of 7 nets, each in a different mesh size, hung vertically on foam rollers from the surface to the bottom of the lake, and chained together in a line. Each net is 4 m wide and 33 m long. From 1981 through 1990 the nets were multifilament mesh, in stretched mesh sizes of 19, 25, 32, 38, 51, 64, and 89 mm. In 1991, the multifilament nets were replaced with monofilament nets of the same sizes. Stretcher bars are installed at 10 meter intervals from the bottom to keep the net as rectangular as possible when deployed.

A boom style electrofishing system is used to sample the littoral zone fish community. Prior to 1997, four electrofishing transects were done on each lake. In 1997, the number of transects was reduced to 3. The same transects are used each year. Each transect consists of 30 minutes of current output, with the boat moving parallel to shore in 1-2 meters of water at a slow steady speed. We use the DC pulse system, with 240 volts at 3-5 amps. Transect lengths vary depending upon the size of the lake. If the end of a transect is reached before 30 minutes has elapsed, time is paused while the electrofisher loops back to the start of the transect. The transect is then repeated for the remaining time.

For all collecting methods, the fish are processed as follows. Each individual fish is identified to species. The total length of the fish is measured in mm, from nose to pinched tail. Prior to 1997, the weight of the first five fish of each species in each 10 mm size category was also measured, using Pesola spring balances. Starting in 1997, two fish are weighed for each species in each 5mm size category. A scale sample is collected from each yellow perch, rock bass, and cisco that is weighed. For gill net catches, the depth at which each individual is caught is also recorded.

Protocol Log. 1983: Discontinued fyke nets and trammel nets on Lake Mendota until 1995. 1984: Discontinued crayfish on Lake Mendota until 1995. Only gillnet and seines on Lake Mendota.1995: Resumed sampling Lake Mendota with the full suite of sampling gear. 1995: Began sampling Lakes Wingra, Monona, and Fish. 1997: Two fish are weighed for each fish species in each 5mm size category. Previously, five fish were weighed for each fish species in each 10mm size category. 1997: Data recording switched from manual field sheets to an electronic system. 1997: Changed from 4 to 3 electrofishing runs per lake. 1997: Changed from 18 to 12 seine hauls per lake. 1998: Changed from 30 to 18 crayfish or minnow traps per lake. 2004: Discontinued crayfish or minnow traps on southern lakes. 2020: Fish sampling very limited due to pandemic. 2021 discontinued all night seining.

DATA MODIFICATIONS
Prior to 2018, gill net data had been standardized to a 24-hour sampling period. This is no longer the case, and catch numbers for all years have been recomputed to reflect the number of fish actually caught.
2018-01-18: Species names ('spname') added in 2012 had space characters appended to the end of the name. These spaces have been removed. The occasional appearance throughout the data set of species name 'SUNFISH' and 'LARVALSUNFISH' have all been changed to 'UNIDSUNFISH'.
Short Name
NTLFI02
Version Number
41

Landscape Position Project at North Temperate Lakes LTER: Benthic Invertebrate Abundance 1998 - 1999

Abstract
Benthic invertebrate assemblages of 32 lakes were surveyed as part of the Landscape Position Project. We used modified Hester-Dendy colonization substrates to sample benthic invertebrate communities. Each sampling device consisted of a 3"x3" top plate, alternating layers of course and fine mesh, a ''choreboy'' commercial scrubbing puff, alternating layers of coarse (6.35 mm) and fine (3.18 mm) black plastic mesh, and a 3"x3" bottom plate. Two Hester-Dendy samplers were set at a depth of one meter on each of three substrate types (cobble, sand and silt) within each lake for four weeks in late June through late July in either 1998 or 1999. Within each lake, areas of different substrate types were identified using WI-DNR depth contour lake maps, and substrate type was verified by direct observation. Different substrates were sampled to account for invertebrate associations with specific substrate characteristics. Lake order was determined using a modification of the method of Riera et al. (2000). Lake order is a numerical surrogate for groundwater influx and hydrological position along a drainage network, with the highest number indicating the lake lowest in a watershed. Riera, Joan L., John J. Magnuson, Tim K. Kratz, and Katherine E. Webster. 2000. A geomorphic template for the analysis of lake districts applied to Northern Highland Lake District, Wisconsin, U.S.A. Freshwater Biology 43:301-18. Sampling Frequency: one survey on each lake in late June through late July of 1998 or 1999 Number of sites: 32
Core Areas
Dataset ID
96
Date Range
-
Maintenance
completed
Metadata Provider
Methods
We used modified Hester-Dendy colonization substrates to sample benthic invertebrate communities. Each sampling device consisted of a 3"x3" top plate, alternating layers of course and fine mesh, a choreboy commercial scrubbing puff, alternating layers of coarse (6.35 mm) and fine (3.18 mm) black plastic mesh, and a 3"x3" bottom plate. Two Hester-Dendy samplers were set at a depth of one meter on each of three substrate types (cobble, sand and silt) within each lake for four weeks in late June through late July in either 1998 or 1999. Within each lake, areas of different substrate types were identified using WI-DNR depth contour lake maps, and substrate type was verified by direct observation. Different substrates were sampled to account for invertebrate associations with specific substrate characteristics. Lake order was determined using a modification of the method of Riera et al. (2000). Lake order is a numerical surrogate for groundwater influx and hydrological position along a drainage network, with the highest number indicating the lake lowest in a watershed. Riera, Joan L., John J. Magnuson, Tim K. Kratz, and Katherine E. Webster. 2000. A geomorphic template for the analysis of lake districts applied to Northern Highland Lake District, Wisconsin, U.S.A. Freshwater Biology 43:301-18. Sampling Frequency: one survey on each lake in late June through late July of 1998 or 1999 Number of sites: 32
Short Name
LPPINVA1
Version Number
6

Lake Wingra: Fish Abundance

Abstract
Data are collected annually to enable us to track the fish assemblages of Lake Wingra. Sampling is done at six littoral zone sites per lake with a beach seine, minnow or crayfish traps, and fyke nets, while a boat-mounted electrofishing system samples four littoral transects. Vertically hung gill nets are used to obtain two pelagic samples per lake from the deepest point. A trammel net samples across the thermocline at two nearshore sites per lake. Fish are identified to species. Lengths are measured for all fish caught, while weight and scale are collected from a subset. Derived data include catch per unit effort and size distribution by species, lake, and year. Protocol used to generate data: Number caught for each species is summed over repetitions of a gear within a lake and over depth. Sampling Frequency: annually. Number of sites: 1. Note that 2020 data does not exist due to insufficient sampling.
Core Areas
Dataset ID
182
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
see abstract.
Short Name
FOLWFI02
Version Number
19

Primary Production and Species Richness in Lake Communities 1997 - 2000

Abstract
An understanding of the relationship between species richness and productivity is crucial to understanding biodiversity in lakes. We investigated the relationship between the primary productivity of lake ecosystems and the number of species for lacustrine phytoplankton, rotifers, cladocerans, copepods, macrophytes, and fish. Our study includes two parts: (1) a survey of 33 well-studied lakes for which data on six major taxonomic groups were available; and (2) a comparison of the effects of short- and long-term whole-lake nutrient addition on primary productivity and planktonic species richness Dodson, Stanley I., Shelley E. Arnott, and Kathryn L. Cottingham. 2000. The relationship in lake communities between primary productivity and species richness. Ecology 81:2662-79. Number of sites: 33
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222
Date Range
-
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completed
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Methods
Our first goal was to understand the relationship between primary productivity and species richness for several groups of freshwater organisms. By species richness, we mean the number of species observed in a lake over a number of years. It is useful to have several years of observations because the number of species observed varies from year to year. We chose the total list of species (the asymptote of the collectors curve) as our index of species richness. The lakes studied as part of the U.S. Long-Term Ecological Research (LTER) Program are particularly valuable because they have been studied for two decades, and complete species lists exist for many kinds of organisms in these systems. LTER lake sites occur in northern and southern Wisconsin and northern Alaska (Toolik Lake). However, because there are fewer than 15 LTER lakes (and only seven with measured rates of primary productivity), we increased sample size by including data from additional well-studied lakes of similar size, but which span a greater range of primary productivity (see Table 1). These lakes have been studied for several years, and estimates of annual primary productivity exist for each lake. Some well-studied lakes were not included, such as those which lacked much of the crucial data, or lakes that were unusually turbid or saline. For example, Lake Okeechobee (Florida, USA) is turbid and exhibits a wide range of productivity levels, depending on the part of the lake sampled, while Marion Lake (British Columbia, Canada) has a flushing rate of only a few days (W. E. Neill, personal communication). Sampling design and protocol are not standardized among studies of lakes. For example, species identifications were done by different people, sampling period was quite variable, and the number of samples per lake was variable. Such heterogeneity reduces the accuracy and precision of relationships between productivity and species richness.Primary productivity.—Pelagic primary productivity (PPR) can be measured by the 14C method (Vollenweider 1974). This method gives a close approximation to gross primary productivity (GPP), but because some of the fixed carbon is respired quickly, the value obtained is less than GPP (Fee et al.1982). Point values of PPR are then integrated by depth and area to produce estimates of whole-lake annual primary productivity per cubic meter or square meter.Lake primary productivity is fundamentally different than productivity measured in other biomes (e.g., grasslands, forests). The 14C method measures available (gross) primary productivity more than utilized (net) production, which is what is normally measured in terrestrial systems. The 14C method is also a fairly direct measure of productivity, compared to the proxy methods (e.g., nutrient loading, biomass, climate, soil fertility) used in many studies.Sampling protocols for aquatic organisms.—Sampling protocols differed among taxonomic groups and lakes (e.g., Downing and Rigler 1984). For example, phytoplankton samples are taken by capturing (at most) a few liters of lake water, either from a specific depth or with a sampler that integrates water across a range of depths. Zooplankton are usually sampled by vertical tows (i.e., raising a net through the water column). Both zooplankton and phytoplankton samples are typically taken from the center of the lake, although replicate samples at different locations may be taken from larger lakes. Planktonic organisms are much smaller than the sampling device, and hundreds to hundreds of thousands of organisms are typically captured in a single sample. In contrast, aquatic macrophytes are sampled using quadrats and rake samples, or simply based on a walk around the lake, while fish are sampled using a variety of nets andoror electroshocking equipment. Criteria for species lists.—Species lists for fish, macrophytes, and pelagic phytoplankton, rotifers, cladocerans, and copepods were obtained from the literature and from unpublished data. We avoided lists restricted to only dominant or common species, and thus included only lists that were exhaustive. Few lakes had species lists for all six groups of organisms. However, we included any lake that had an estimate of the average annual primary productivity and had lists for at least three taxa.We standardized this database by developing criteria for inclusion of species in analyses. Phytoplankton lists included all prokaryotic and eukaryotic photosynthetic phytoplankton for which there were abundances of more than one organism per milliliter (a criterion also used by Lewis 1979). We included all nonsessile species caught in open water as pelagic rotifers. For the crustacean zooplankton (cladocerans and copepods), we followed the criteria of Dodson (1992). Species lists of macrophytes included all submerged, floating, or emergent species of flowering plants, including Typha, sedges, grasses, and duck weed. We did not include Isoetes or macroalgae such as Chara and Nitella as macrophytes. The fish list included all species reported from the lake, including introduced taxa. Fish species reported to occur in the watershed, but not in the lake (as in Pearse1920) were not considered part of the lakes biota.
Short Name
DODSON1
Version Number
26
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