|
|
Botanical Research and Activities
Botanical
Reasearch and Activities of the PA Flora Project
Survey of Aquatic Vascular PlantsNatural Resource Inventories of State Parks Municipal Contracts Survey of Aquatic Vascular Plants
For the past four years, with funding from the Pennsylvania Wild Resources Conservation Fund,
we have been conducting surveys of aquatic vascular plants on lakes in eastern Pennsylvania. To
date we have surveyed 92 lakes with the following results.
Most common native aquatic species and the number of lakes in which they were found Nuphar variegata 66 Potamogeton epihydrus 60 Sparganium americanum 57 Nymphaea odorata 53 Brasenia schreberi 47 Dulichium arundinaceum 44 Utricularia macrorhiza 43 Pontederia cordata 42 Eleocharis palustris 41 Sagittaria latifolia 37 Najas flexilis 34 Decodon verticillata 34 Elodea nuttallii 33 Invasive, non-native plants and the number of lakes in which they were found Potamogeton crispus 14 Elatine triandra 11 Myriophyllum spicatum 10 Nymphaea pink-flowered 9 Lythrum salicaria 9 Phragmites australis 5 Polygonum cuspidatum 4 Trapa natans 3 Cabomba caroliniana 3 Hydrilla verticillata 1 As a result of our surveys we have recommended that the following species be dropped from the state lists of endangered, threatened, and rare species, as they are more abundant than was previously realized. Eleocharis olivacea Glyceria borealis Gentiana linearis Najas gracillima Orontium aquaticum Polygonum aquaticum var. stipulaceum Potamogeton bicupulatus Potamogeton robbinsii Utricularia geminiscapa Utricularia purpurea Wolffia borealis Xyris montana Other Findings Long-stem waterwort (Elatine triandra) - We have continued to discover additional populations of a species of Elatine (waterwort) that we initially identified as American waterwort (E. americana). However, in Pennsylvania, American waterwort has traditionally been limited to the intertidal areas of the Delaware River, where it has not been collected for more than 50 years (Rhoads and Klein 1993). After finding this species at several very degraded lakes in southeastern Pennsylvania this year, we checked further into its identification and have concluded that the specimens in question are long-stem waterwort (Elatine triandra), a species not previously recorded for Pennsylvania. Gordon Tucker, who is preparing the treatment of the Elatinaceae for Flora North America, has confirmed that our specimens are E. triandra. Elatine triandra is native to Eurasia and western North America. It has been collected in Maine, where it is considered to be introduced (Haines and Vining 1998; Tucker 1986), and recently at several locations in New York (G. Tucker, personal communication). Taxonomic confusion has further obscured the true identity of the waterworts. American waterwort was considered to be a variety of E. triandra; Gleason and Cronquist (1991) list it as Elatine triandra Schkuhr var. americana (Pursh) Fassett, whereas E. triandra is Elatine triandra Schkuhr var. triandra. Other authors (Tucker 1986; Crow and Hellquist 2000) recognize both American and long-stem waterwort at the species level as Elatine americana (Pursh) Arn. and E. triandra Schkuhr respectively. We have concluded that the plant we initially collected as Elatine americana at eight lakes in Luzerne, Pike, Susquehanna, and Berks Counties is, in fact, E. triandra, and that this species is apparently spreading rapidly within our range. Inspection of herbarium specimens at the Academy of Natural Sciences of Philadelphia indicates that E. triandra is also present at one additional lake in Pike County, and that it has been at Twin Lakes in Pike County since at least 1960. Inflated bladderwort (Utricularia inflata) - Inflated bladderwort is another plant that shows very aggressive tendencies. This species was first collected in Pennsylvania at three sites in Sullivan County 1993-1997, but recorded at the time as U. radiata, a similar but smaller plant, which had previously been considered a variety of U. inflata. However, Peter Taylor in his monograph on the genus Utricularia (Taylor 1989) recognized both taxa at species rank as did Crow and Hellquist (2000). It has now been found by us at eight lakes in northeastern Pennsylvania and is undoubtedly present at others. Inflated bladderwort is native to the coastal plain from Delaware to Florida and Texas (Gleason and Cronquist 1991); we probably will never know exactly how it became established in Pennsylvania. It is also known from a single site in New York (Mitchell et al. 1994) and one in Massachusetts (Sorrie 1992). Following our recognition of its presence at Pecks Pond and Tobyhanna Lake in 2000, it was added to the Pennsylvania Natural Heritage Program plant list with a TU (tentatively undetermined) classification. However, it appears to be spreading even to lakes that are not visited by boaters such as Beech Lake in State Game Lands 57; waterfowl may be the vector. Like purple bladderwort, inflated bladderwort can become very abundant locally, causing distress to various recreational users. It is frequently present in vegetative condition only; we have learned to recognize it in the absence of flowering stems based on leaf and stem tip characteristics. Utricularia inflata has a G5 (globally secure) rating overall; it is S1 (critically imperiled) in MI, NY, NJ, DE, MD, TN, AL, and OK. It is rated as S2 (imperiled) in VA and NC. It is considered invasive in Washington State, the only western state in which it has been found (NatureServe 2004; Washington State Department of Ecology 2004). Broad-leaved water-milfoil (Myriophyllum heterophyllum) - We have previously (Rhoads and Block 2001) reported on large populations of Myriophyllum heterophyllum (broad-leaved water-milfoil) that are present at several eastern Pennsylvania lakes. During our 2003 surveys we documented two additional occurrences of this aggressive species and noted the expansion of one previously recorded occurrence. At Harris Pond in Luzerne County, a PA Fish and Boat Commission lake, Myriophyllum heterophyllum dominated the entire lake. It was rooted throughout, except in the deepest central region; in addition, floating fragments covered the water surface in the vicinity of the dam and extending for about one-third the length of the lake. We documented an additional population in the inlet at Harvey’s Lake, where the presence of this species was first noted by A. E. Schuyler in 1982. Interestingly, we did not see this species anywhere else in this large lake although it is abundant in the inlet. A revisit to Lily Lake, another PA Fish and Boat Commission site in Luzerne County, revealed a dramatic expansion in the area occupied by Myriophyllum heterophyllum compared to our previous visit in 2001. Myriophyllum heterophyllum is classified as G5 (globally secure); in 6 states or provinces it is classified as S1 (critically imperiled): New Brunswick, IA, OH, PA, MD, DE. It has S2 (imperiled) status in Quebec, NJ, KY, and NC. It is considered secure in Ontario and VA. Vermont, Hew Hampshire, New York, Rhode Island, and the District of Columbia consider Myriophyllum heterophyllum to be exotic (NatureServe 2004; New Hampshire Department of Environmental Services. 1999). Resources: Crow, Garrett E. and C. Barre Hellquist. 2000. Aquatic and Wetland Plants of Northeastern North America. The University of Wisconsin Press, Madison Haines, Arthur and Thomas F. Vining. 1998. Flora of Maine, a Manual for Identification of Native and Naturalized Vascular Plants of Maine. V. F. Thomas Co., Bar Harbor, ME. Mitchell, Richard S., Terryanne E. Maenza-Gmelch, and J. G. Barbour. 1994. Utricularia inflata Walt. (Lentibulariaceae) new to New York State. Bull. Torrey Botanical Club 121(3): 295-297. NatureServe Explorer http://www.natureserve.org/explorer/ accessed 1/16/2004. Rhoads, A. F. and W. M. Klein. 1993. The Vascular Flora of Pennsylvania: Annotated Checklist and Atlas. American Philosophical Society, Philadelphia, PA Sorrie, Bruce A. 1992. Utricularia inflata Walter (Lentibulariaceae) in Massachusetts. Rhodora 94: 391-392. Taylor, P. 1989. The Genus Utricularia – A Taxonomic Monograph. Royal Botanic Gardens Kew, London Tucker, Gordon C. 1986. Genera of Elatinaceae in the southeastern United States. Journal of the Arnold Arboretum 67(4): 471-483. Washington State Department of Ecology, http://www.ecy.wa.gov/programs/wq/plants/weeds/bladder.html, accessed 1/26/2004. Natural Resource Inventories of State Parks
The Botany Department of the Morris Arboretum is one of 3 organizations under contract with the
Pennsylvania Bureau of State Parks to conduct natural resource inventories of selected state
parks. The Western Pennsylvania Conservancy and The Pennsylvania Science Office of The Nature
Conservancy are the other participants.
During the first 3-year cycle we concentrated on designated natural areas in French Creek, Neshaminy, Delaware Canal, Hickory Run and Tobyhanna state parks. In addition we inventoried the entire area of Nescopeck State Park where we documented the largest known population of the globally rare sedge, Carex polymorpha and an overall diversity of vascular plants exceeding 650 taxa in the 3,117-acre park. We are currently working on Nockamixon, Lackawanna, Archbald Pothole, Gouldsboro, and Lehigh Gorge state parks and the recently acquired Varden Conservation Area in southern Wayne County. Our charge in this second cycle is too look at natural resources throughout the parks. We are preparing maps of vegetation types, compiling specie slists, and noting infestations of invasive species. In addition we are subcontracting with selected specialists to prepare surveys of reptiles and amphibians. Municipal Contracts
Pond at Whites Mill PreserveWhites Mill Preserve This approximately 100-acre tract was acquired in 1998 by Salford Township, Montgomery County, Pennsylvania. The township contracted with the Botany Department of Morris Arboretum to prepare an inventory and management guidelines for the preserve which includes a 150-year old mill pond, a forested diabase slope, floodplain meadow, and successional areas. Mead’s sedge (Carex meadii), a state endangered species is present. The site also contains a large naturalized population of callery pear (Pyrus calleryana). Magnolia virginiana Fallsington Wetland Falls Township, Bucks County, Pennsylvania contracted with the Botany Department of the Morris Arboretum to prepare an inventory and management recommendations for an extensive coastal plain wetland complex acquired by the township under the Bucks County Open Space Program. We documented the presence of five rare coastal plain plants, willow oak (Quercus phellos), netted chain fern (Woodwardia areolata), sweetbay magnolia (Magnolia virginiana), round-leaved eupatorium (Eupatorium rotundifolium), and short-hair sedge (Carex crinita var. brevicrinis); rare coastal plain forest types; and discussed measures to reduce the spread on invasive species. Scirpus georgianus East Goshen Township Wetland East Goshen Township, Chester County, Pennsylvania has engaged us to do an inventory of a 15-acre wetland recently acquired as township open space. This work will take place during the spring and summer of 2004.
|
