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Higgins eye (Lampsilis higginsii) Essential Habitat Areas

2008 Review and Addition of New EHAs

Below is the text only, click here for the complete report: text, tables, maps and references (9-page PDF, 1.5MB)

 

Background

U.S. Fish and Wildlife Service’s (Service) recovery plan for Higgins eye (Lampsilis higginsii, U.S. Fish and Wildlife Service 2004) focuses on the recovery of the species within Essential Habitat Areas (EHA). In the plan, the Service described ten EHAs, but also noted that it intended to “assess other areas that may contain the features that indicate that they are of utmost importance for the conservation of Higgins eye.”

 

In this document, we describe four new EHAs that the Service has added, in consultation with the recovery team. In each of these areas, recent survey data indicates that key characteristics of the mussel beds exceed the Higgins eye EHA guidelines (Table 1). Therefore, there are now fourteen EHAs – the ten described in the recovery plan plus the four new EHAs described below.

 

Mapping New EHAs

In each case, we based the longitudinal boundaries of the new and proposed EHAs on the up- and downstream limits of the mussel bed, using the EHA guidelines (e.g., >10 mussels/m2) and recent reports (Table 1) to define the mussel bed. For main channel areas we used the shoreline and the thalweg1 to determine the lateral breadth of EHAs (e.g., see Fig. 2). If the EHA mussel bed was contained in a slough outside of the main channel, the EHA extends between the lateral boundaries of the slough, as represented by shorelines, vegetated islands, point bars, intersections with other sloughs, etc. (e.g., see upstream portion of Fig. 1).

 

UMR, Pool 11, RM 606-608 – Cassville, Wisconsin

The polygon for this site (Fig. 1) was digitized based on the location of the mussel bed (Ecological Specialists Inc. 2006) and modified to align with shoreline and other features as depicted in USGS quadrangle map and the 2006 color aerial photograph. The mussel bed in this area extends upstream of the EHA, but data are not yet sufficient to determine whether the characteristics of the bed (e.g., see Table 1) warrant extending the boundaries of the EHA further upstream (Winterringer & Dunn 2008)

 

UMR, Pool 9, RM 660-661 – Near Lansing, Iowa

The polygon for this EHA (Fig. 2) was hand digitized based on the area in which the mussel bed was mapped based on qualitative sampling conducted 24-26 May 2005 (Table 1, E. Belt, Ecological Specialists, Inc., O’Fallon, MO, pers. comm. 14 February 2008). We then adjusted the boundaries to better align with the shoreline areas as depicted by the USGS 24K quadrangle map and extended the EHA laterally to the thalweg (Fig. 2).

 

UMR Pool 16, RM 470-471 – Near Buffalo, Iowa

We hand digitized a polygon around the locations of high density samples, (>10 mussels/sq. m, Helms 2003) to delineate the approximate boundaries of the mussel bed and then adjusted the boundaries to better align with the shoreline areas as depicted by the quadrangle map and 2006 color aerial photograph and extended the EHA laterally to the thalweg (Fig. 3).

 

UMR, Pool 14, RM 509.1 -510.1 (Hanson’s Slough)

We hand digitized the mussel bed based on a polygon of the bed sampled by Ecological Specialists, Inc. in 2007 (Ecological Specialists 2008), extending the EHA from the right descending bank laterally to the thalweg and, in part, to more proximate islands and bars (Fig. 4).

 

 

1 We used the GIS layer, RECTRC (“Recommended Track” – Inland Electronic Navigation Charts, http://www.tec.army.mil/echarts/inlandnav/) to represent the thalweg (see the red line in Figs. 1-3).

 

Below is the text only, click here for the complete report: text, tables, maps and references (9-page PDF, 1.5MB)

 

Back to Higgins Eye Page

 

Last updated: July 16, 2014