04-14-20 Comments Provided to USFWS for Designation of Critical Habitat for the Yellow Lance (Elliptio lanceolata)
- Written by Matthew Coughlin-Environmental Reviewer, B.S Environmental Science & Technology
- Category: COMMENTS PROVIDED FOR: Federal Agencies
- Hits: 99
US Fish & Wildlife Services
5275 Leesburg Pike,
Falls Church, VA 22041-3803
The Yellow Lance (elliptio lanceolata) was listed as threatened in April of 2018 and is presumed to be extirpated from 25% of its historically occupied management units. As with all varieties of freshwater mussels, the Yellow Lance is a filter feeder that helps remove excess algae, bacteria, and other organic matter from the water column, providing an ecosystem service of improving water quality. The ecological benefits of this species in tandem with its current population decline merit swift legal action in order to establish a critical habitat.
The Yellow Lance - Species is listed as Threatened in Maryland, Virginia, & North Carolina
Page 173 of Section 319 of the Clean Water Act lists management programs set in place to mitigate nonpoint source pollution, yet pollutants of concern are still threatening Yellow Lances populations. It is crucial that in protecting 319 river miles of critical habitat, effective management practices are utilized. The study Riparian Buffer Zones: Functions and Recommended Widths (Hawes and Smith, 2005) references scientific studies to establish a list of riparian buffer widths necessary to serve specific purposes for protecting stream ecosystems. For erosion and sediment control, a width of 30-98 ft is recommended. In the case of absorbing biocontaminants, nutrients, and pesticides, the width ranges are 30+ft, 49-164ft, and 49-328ft respectively. What are the challenges to implementing vegetative buffers and other management practices?
Out of the four scenarios outlined on page 74 of the Species Status Assessment Report (SSAR), scenarios 1 and 2 (Status Quo and Pessimistic respectively) appear to be most likely to occur within a fifty year timespan. For scenario 1, (noted as greater than 90% likely to occur) a substantial loss of resiliency would be observed with none of the twelve management units being in high condition and potentially 8/12 of all management units being extirpated. The pessimistic outlook (noted as 70-90% likely to occur) projects a near complete loss of resiliency. If the most likely scenario (the Status Quo) could result in a ⅔ loss of management unit populations, what can be done to prevent such losses?
According to page 7 of the SSAR, the Yellow Lance is dependent on attaching itself to minnows to successfully reach its adult stage. Though it is likely true that the Yellow Lance is mostly being hindered by abiotic factors such as pollution and sedimentation, establishing a critical habitat for this mussel species should also address conditions necessary for the survival of its host species to ensure proper development. The Yellow Lance’s glochidia stage coincides with the spawning period of minnows -- from late spring to mid summer. Minnows are obligate hosts for this species and require support in order to ensure proper development of the Yellow Lance. How can this critical habitat be tailored to also meet the needs of the Yellow Lance’s obligate hosts?
The genetic homogeneity of Yellow Lance populations is largely due to the species’ sessile nature. These isolated populations are unable to interbreed and cannot escape water pollution by moving to more habitable areas. However, if favorable conditions are present for the mussels and their obligate hosts, it is possible that the geographic range of the mussels could expand within the watershed resulting in genetic overlap between populations. The Proposed Rule document states that areas outside of the Geographic Area Occupied at the time of listing are not being considered as part of a designated critical habitat. Is focusing only on the Geographic Area Occupied a good idea if we hope to restore this species to its historic population and range?
Concerns noted on page 54 of the SSAR are small population sizes and habitat fragmentation potentially reducing genetic diversity and resiliency of the extant populations. Would a baseline study of population genetics for each population and an effort to mass propagate Yellow Lance mussels be an effective means of combating this lack of genetic diversity?
Hawes, E. and Smith, M. (2005). Riparian Buffer Zones: Functions and Recommended Widths. Prepared for the Eightmile River Wild and Scenic Study Committee.
U.S. Fish and Wildlife Service. 2017. Species Status Assessment Report for the Yellow Lance (Elliptio lanceolata). Version 1.2. March, 2017. Atlanta, GA.
Matthew Coughlin - Associate in Maryland
Environmental Review Inc.
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San Jose, California 95112