Invasive Species found in Black Lake
The presence of the non-native invasive aquatic plant, Eurasian watermilfoil (milfoil – Myriophyllum Spicatum), is common to many lakes throughout Washington and the Pacific Northwest.
The growth of milfoil in Black Lake limits recreation, navigation, disrupts natural water flow, and adversely impacts aquatic habitat and water quality. To date, hand pulling has been employed to control plant density by physically removing plants. This method of control has prevented the rapid expansion of both the area covered and density potential of this nuisance plant. For more information about Eurasian Water-milfoil, visit the Dept of Ecology website.
Two other non-native plants are also adversely impacting the ecological balance of Black Lake and its beneficial uses. Specifically, yellow iris (Iris pseudacorus) and white waterlily (Nymphaea odorata) are encroaching upon the shoreline and open water area of the lake.
Not only are all parts of yellow iris poisonous, causing skin irritation, but the plant forms dense colonies that alter shoreline and aquatic habitat. The white waterlily can grow to nuisance densities and, in response to high nutrient availability, accelerate nutrient over-enrichment of a water body.
Two native plants are also found in notable densities in Black Lake, slender water-nymph (Najas flexilis) and spatterdock (Nuphar polysepala). Dense growth of water-nymph is a likely a response to the lake’s nutrient supply as it forms some dense colonies that directly impacts some recreational uses. On the other hand, water-nymph provides direct aquatic habitat benefits to fishes and invertebrates and is an important food source for waterfowl. The plant also serves to balance the primary production in the lake by providing direct and indirect competition for nutrients versus the cyanobacteria (blue-green algae) that also have produced blooms in the lake. Spatterdock also provides aquatic habitat and is a direct food source for aquatic biota, but its current coverage is not presenting a nuisance relative to the beneficial uses of Black Lake.
Click Here to see larger line drawing map of Black Lake with Invasive Species locations.