Quantitative Plant Surveys: Arcadia and Metacomet Lakes Mark June-Wells, Ph.D. Director, Water Resource Services All Habitat Services LLC. NALMS Certified Lake Manager
Non-native Aquatic Plant Species
Why are Non-native Plants a Threat?
Quantitative Plant Surveys Purposes: To evaluate the structure of the plant community. Understand the mathematical features of the plant community. Develop an inventory of all plant species. Determine the distribution of all species. Evaluate the extent of non-native species invasion. Uses To determine the impacts of plant control measures. To determine the necessity of further plant control.
Experimental Design Random Point Survey 20 Points (0.1 5.0m) Depth Grapple Tosses (x4) Plants Identified Rank Abundances Plant Community Characteristics Percent Composition Richness Diversity Abundance Community Structure Models
Findings Arcadia Lake 0.83 0.83 Arcadia Lake 0.83 1.65 2.48 Cabomba caroliniana Sagi aria graminea Vallisneria americana 13.22 24.79 12.40 11.57 3.31 4.13 4.13 9.09 4.13 6.61 Eriocaulon aqua cum Utricularia macrorhiza Sparganium Ela ne minima Ludwigia palustris Potamogeton amplifolius Utricularia radiata Myriophyllum heterophyllum Nymphaea odorata Utricularia purpurea Utricularia gibba Potamogeton bicupulatus Species Percent Potamogeton bicupulatus 24.79 Utricularia gibba 13.22 Utricularia purpurea 12.40 Nymphaea odorata 11.57 Myriophyllum heterophyllum 9.09 Utricularia radiata 6.61 Elatine minima 4.13 Ludwigia palustris 4.13 Potamogeton amplifolius 4.13 Sparganium 3.31 Utricularia macrorhiza 2.48 Eriocaulon aquaticum 1.65 Cabomba caroliniana 0.83 Sagittaria graminea 0.83 Vallisneria americana 0.83 Lake Arcadia Species List Brasenia schreberii Cabomba caroliniana Elatine minima Eriocaulon aquaticum Ludwigia palustris Myriophyllum heterophyllum Nymphaea odorata Potamogeton amplifolius Potamogeton bicupulatus Potamogeton epihydrus Sagittaria cuneata Sagittaria graminea Sparganium spp. Utricularia gibba Utricularia macrorhyza Utricularia purpurea Utricularia radiata
Shannon's Index Total Rank Abundance Species Richness Findings Arcadia Lake Arcadia - Depth vs. Total Abundance Arcadia - Depth vs. Species Richness 12 10 y = -0.1712x + 6.3721 R² = 0.00471 8 7 y = -0.1231x + 3.5316 R² = 0.00824 8 6 6 5 4 4 2 3 2 1 0 0 0.5 1 1.5 2 2.5 3 3.5 Depth 0 0 0.5 1 1.5 2 2.5 3 3.5 Depth Arcadia - Depth vs. Community Diversity 2 1.8 1.6 y = 0.0175x + 1.0407 R² = 0.00141 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 2.5 3 3.5 Depth
Findings Arcadia Lake
Findings Metacomet Lake 22.73 24.24 Metacomet Lake 3.03 3.03 3.03 4.55 4.55 6.06 7.58 21.21 Brasenia schreberii Myriophyllum heterophyllum Pontederia cordata Eleocharis acicularis Potamogeton spirillus Sparganium Potamogeton bicupulatus Cabomba caroliniana Nymphaea odorata Utricularia purpurea Metacomet Species List Brasenia schreberii Cabomba caroliniana Eleocharis acicularis Myriophyllum heterophyllum Nymphaea odorata Pontederia cordata Potamogeton bicupulatus Potamogeton epihydrus Potamogeton spirillus Sagittaria graminea Sparganium spp. Typha lattifolia Utricularia macrorhyza Utricularia purpurea Vallisneria americana Species Percent Utricularia purpurea 24.24 Nymphaea odorata 22.73 Cabomba caroliniana 21.21 Potamogeton bicupulatus 7.58 Sparganium 6.06 Eleocharis acicularis 4.55 Potamogeton spirillus 4.55 Brasenia schreberii 3.03 Myriophyllum heterophyllum 3.03 Pontederia cordata 3.03
Shannon's Index Shannon's Index Richness Findings Metacomet Lake Metacomet - Depth vs. Total Abundance Metacomet - Depth vs. Species Richness 12 6 10 8 y = 0.9737x 2-6.7226x + 11.363 R² = 0.6827 5 4 y = 0.5092x 2-3.3706x + 5.4417 R² = 0.77148 6 3 4 2 2 1 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Depth 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Depth Metacomet - Depth vs. Community Diversity 1.8 1.6 1.4 1.2 y = 0.2173x 2-1.346x + 2.0015 R² = 0.7616 1 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Depth
Findings Metacomet Lake
Overall Conclusions Previous herbicide applications have controlled the non-native species in both lakes. Herbicide activities have shifted the dominant members of the plant community in both lakes. Continued chemical management is not necessary in either lake this year; non-native species are not strongly dominant or impeding recreation in either lake. Potamogeton bicupulatus is or will be at nuisance levels in Arcadia Lake. Mechanical harvesting is recommended. A monitoring approach to non-native species management is recommended for both lakes; this should include triggers for chemical management. Water quality should be monitored in both lakes.
Herbicides Management Options
Mechanical Management Options
Management Recommendations Both Lakes Plant Community Monitoring Yearly Inspection When Non-natives reach nuisance levels Management Trigger. Water Quality Monitoring Monthly (May - October) Variables: Algae Alkalinity Ammonia Conductivity Dissolved Oxygen Nitrate/Nitrite ph Total Kjeldahl Nitrogen Total Phosphorus
Management Recommendations Both Lakes Technical Plant Control Matrix Protocol Target Species Timing Amount per Acre-foot Total Amount per Acre (4ft average) Technique Carfentrazone Myriophyllum heterophyllum Target Date - June 1st 0.287gal 1.15gal Trailing Hoses Flumioxazin Cabomba caroliniana Target Date - July 1st 1.05lbs 4.2lbs Trailing Hoses Carfentrazone: $690.00/acre (w/4ft average depth). Flumioxazin: $1,190.00/acre (w/4ft average depth).
Specific Management Recommendations Arcadia Lake: Mechanical harvesting of P. bicupulatus. ~$2,500.00/acre
Mark June-Wells, Ph.D. NALMS Certified Lake Manager ESA Certified Ecologist (203)-245-1212 (203)-619-3322 mjunewells@allhabitat.com Questions?