Biological Assessment Potential Impacts to the Red Knot Associated with Maintenance Dredging Activities at Macdill Air Force Base Tampa, Florida

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BIOLOGICAL ASSESSMENT POTENTIAL IMPACTS TO THE RED KNOT ASSOCIATED WITH MAINTENANCE DREDGING ACTIVITIES AT MACDILL AIR FORCE BASE TAMPA, FLORIDA

Prepared for: MacDill Air Force Base 7621 Hillsborough Loop Drive, MacDill AFB, Florida 33621

Prepared by: ANAMAR Environmental Consulting, Inc. 2106 NW 67th Place, Suite 5 Gainesville, Florida 32653-1658

May 2015

Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Table of Contents 1 INTRODUCTION ...... 1 1.1 Project Area ...... 1 1.2 Proposed Action ...... 4 1.3 History of Consultation ...... 7 1.4 Protected Species of Consideration ...... 7 1.5 Regulatory Framework ...... 7 1.5.1 National Environmental Policy Act of 1969 (NEPA) ...... 7 1.5.2 Endangered Species Act of 1973 ...... 8 1.5.3 Migratory Bird Treaty Act of 1918 ...... 8 2 THE RED KNOT ...... 9 2.1 Description ...... 9 2.2 Range and Populations ...... 10 2.2.1 Populations in Florida ...... 11 2.3 Seasonality and Habitat Use in Florida ...... 12 2.3.1 Sightings and Habitat Use at MacDill AFB ...... 15 2.4 Threats to Red Knots in Florida ...... 23 2.5 Conservation and Protection ...... 24 2.5.1 Critical Habitat ...... 25 2.6 Discussion ...... 29 2.6.1 Potential Threats to Red Knots ...... 29 3 EFFECTS ANALYSIS OF PROPOSED ACTION ...... 30 3.1 Red Knots ...... 30 3.2 Critical Habitat ...... 30 3.3 Conservation Measures ...... 30 4 REFERENCES ...... 32

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List of Exhibits Exhibit 1-1. Overview of Navigation Channels, Basins, and Surrounding Area Proposed for Maintenance Dredging, MacDill AFB ...... 2 Exhibit 1-2. Schematic of Navigation Channels and Associated Boat Basins Proposed for Maintenance Dredging, MacDill AFB ...... 3 Exhibit 1-3. The Beach Area Adjacent to the Navigation Channel Complex, MacDill AFB. Sheet Piling Is Proposed for Upland Installation at the Westernmost Tip of the Beach Area...... 5 Exhibit 1-4. Plan View Drawing of the Proposed Sheet Piling to be installed at the Westernmost Tip of the Beach Area...... 6 Exhibit 1-5. Cross Section Drawing of the Proposed Sheet Piling to be installed at the Westernmost Tip of the Beach Area...... 7 Exhibit 2-1. Adult Red Knot in Non-breeding Plumage, Sanibel Island, Florida ...... 10 Exhibit 2-2. Counts of Red Knots along Florida’s Gulf Coast over a Period of Three Winters (2004–2008)...... 12 Exhibit 2-3. Red Knot Habitat Usage per State in the Eastern U.S. Florida Is Both an Overwintering Area and a Stopover for the Species...... 13 Exhibit 2-4. Observations of the Red Knot during Four Bird Counts from December 1993 through March 1994 at 23 Sites in Florida, in Decreasing Order of Maximum Number Recorded ...... 14 Exhibit 2-5. Abundance (n/checklist) of Red Knots per Week in Hillsborough County, Florida, Based on Data Reported to eBird...... 15 Exhibit 2-6. Summary of All Sightings of Red Knots at MacDill AFB Reported to eBird to 05/11/15...... 16 Exhibit 2-7. Checklists Submitted to eBird for MacDill AFB Reference This Geographic Locality...... 17 Exhibit 2-8. A Large Mudflat Is Exposed during Low Tide East of the Security Checkpoint along Bayshore Boulevard. Red Knots Have Been Observed Using This Mudflat...... 18 Exhibit 2-9. Red Knots Have Been Observed Using an Armored Section of Shoreline East of Bayshore Boulevard. Horseshoe Crabs Have Been Observed along This Section of Armored Shoreline As Well...... 19 Exhibit 2-10. Red Knots Have Been Observed along the Beach Area of MacDill AFB, near the Water’s Edge. Observed Behaviors Consisted of Both Roosting and Foraging. Horseshoe Crabs Were Observed in the Spring of 2008 at the Western Tip of the Beach Area...... 20 Exhibit 2-11. The Beach Area at MacDill AFB Is Bordered by Mangrove Swamp Habitat to the West and East, Indicating That the Beach Area Was Once Also Mangrove Habitat...... 21 Exhibit 2-12. Horseshoe Crab Spawning Aggregation at the Western Tip of the Beach Area, Photographed on April 11, 2008...... 23

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Exhibit 2-13. Areas of Florida Affording Protection to Red Knots from Chronic Disturbance by Humans ...... 25 Exhibit 2-14. Unofficial Critical Habitat for the Red Knot in Florida as Described by Niles et al. (2008) ...... 26 Exhibit 2-15. Unofficial Critical Habitat for the Red Knot in Northern Florida as Described by Niles et al. (2008) ...... 27 Exhibit 2-16. Unofficial Critical Habitat for the Red Knot in Southern Florida as Described by Niles et al. (2008). MacDill AFB Is Not Considered Critical Habitat by these Authors...... 28

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ACRONYMS, ABBREVIATIONS & INITIALISMS

AFB Air Force Base BA biological assessment CEQ Council on Environmental Quality COSEWIC Committee on the Status of Endangered Wildlife in Canada EA Environmental Assessment EIS Environmental Impact Statement ESA Endangered Species Act of 1973 F.A.C. Florida Administrative Code FONSI Finding of No Significant Impacts km kilometer(s) MLW mean low water NEPA National Environmental Policy Act of 1969 NMFS National Marine Fisheries Service nmi nautical mile USACE U.S. Army Corps of Engineers U.S.C. U.S. Code USFWS U.S. Fish and Wildlife Service

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1 INTRODUCTION MacDill Air Force Base (MacDill AFB) is near Gadsden Point in Tampa, Florida (Hillsborough County), and is surrounded by Old Tampa Bay, Hillsborough Bay, and Tampa Bay. Navigational channels and associated basins at the base have experienced accretion of sediments from a combination of slow deposition over time and stochastic events such as Tropical Storm Debby in 2012. Maintenance dredging is required to ensure the continued safe passage of patrol watercraft of the 6th Security Forces Squadron, use of boat storage facilities in the primary marina and northwest boat basin, and to gain access to onshore storage facilities. The 6th Security Forces Squadron marine patrol watercraft provide necessary enforcement of the marine exclusion zone and restricted area as identified under Title 33 Part 334 of the Code of Federal Regulations. Currently, the patrol vessels are unable to transit the channel during low tides. This limitation compromises the ability of MacDill AFB to respond to unauthorized entry into the marine exclusion zone that surrounds the base (MacDill AFB 2014).

1.1 Project Area Exhibits 1-1 and 1-2 provide an overview and a schematic, respectively, of the project area. The channel complex is contained within Sections 34 and 35, Township 30 south, and Range 18. The area of Tampa Bay surrounding MacDill AFB is considered a Class II surface water body by the State of Florida (Rule 62-302.400, F.A.C.). Channel A (the entrance channel) is 50 feet wide and is maintained at a project depth of -7 feet mean low water (MLW) plus 1 foot overdepth between Station 16+50.00 and Basin A (the primary marina). Channel A connects MacDill AFB with Tampa Bay and Gadsden Point Cut to the south. Channel B (the northwest channel) connects Basin B (Raccoon Creek Marina) with Channel A. Channel B is 50 feet wide and is maintained at a project depth of -7 MLW plus 1 foot overdepth between Stations 60+00.00 and 76+50.00, and at -5 feet MLW (with no overdepth) between Station 76+50.00 and Basin B (FDEP 2005). The total length of the channel complex (Channel A plus Channel B) is 7,420 feet (1.2 nmi) (MacDill AFB 2014). Basin A is at the northern terminus of Channel A and houses 6th Security Forces patrol watercraft and rental boats along floating concrete docks. Basin A is proposed for maintenance dredging to a width of 150 feet. A boat ramp along the western edge of Channel A and south of Basin A is used by 6th Security Forces to launch patrol watercraft. Channel B includes a portion of the Raccoon Hammock Creek- Broad Creek system and connects Channel A with Basin B. Basin B houses personal watercraft such as sailboats along leased slips.

The approximately 5-acre upland disposal area is 650 feet west of the Family Campground entrance (MacDill AFB 2014). The disposal area is comprised of a rectangular-shaped 3.3-acre settling pond, a 1-acre decant pond, and a 0.7-acre drain area that connects the settling pond with the decant pond (AECOM 2012). The existing soils of the disposal site were classified by AECOM (2012) as a combination of dredged material composed of grayish-brown clay of low plasticity and native soils composed of light gray and brown sand.

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Decant Pond

Settling Pond Basin B

Basin

A Channel B Channel

Exhibit 1-1. Overview of Navigation Channels, Basins, and Surrounding Area Proposed for Maintenance Dredging, MacDill AFB Source: Modified from Figure 1 of AF Form 813, Marina Maintenance Dredging (MacDill AFB 2014)

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Basin B

Basin

Channel B Channel

Exhibit 1-2. Schematic of Navigation Channels and Associated Boat Basins Proposed for Maintenance Dredging, MacDill AFB Source: Modified from Figure 4 of AF Form 813, Marina Maintenance Dredging (MacDill AFB 2014)

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1.2 Proposed Action Channel A is proposed for dredging along its entire length, with a project depth of -7 feet MLW plus 1-foot overdepth. Much of Basin A is proposed for maintenance dredging to a project depth of -7 feet MLW plus 1 foot overdepth and up to a width of 150 feet. Channel B is proposed for maintenance dredging along all or most of its length. Dredging between Stations 60+00.00 and 76+50.00 will be to a project depth of -7 feet MLW plus 1 foot overdepth. Dredging northward of Stations 76+50.00, including Basin B, will be to a project depth of -5 feet MLW plus 1 foot overdepth (M. Tyl, MacDill AFB, pers. comm. 12/12/14). Approximately 100 linear feet of sheet piling is proposed to be installed in the upland beach area along the east side of the ‘pinch point’ of Channel B at Station 76+21.65 to stabilize the beach area and prevent erosion. The sheet piling will facilitate the shifting of the bend in the channel at Station 76+21.65 approximately 10 feet eastward, allowing full avoidance of impacts to mangroves and seagrass associated with the western bank. The approximate area of proposed installation of the sheet piling is shown in Exhibit 1-3. Exhibits 1-4 and 1-5 show the plan view and cross section view, respectively, of the sheet piling based on engineering drawings dated 15 May 2015.

The maintenance dredging will include up to 6,430 feet (1.1 nmi) of channel (including both basins) and will be accomplished by hydraulic dredge (MacDill AFB 2014). The volume of material to be removed from Channel A and Basin A is estimated at 20,000 cubic yards. The volume of material to be removed from Channel B and Basin B is estimated at 5,000 cubic yards (J. Kirkpatrick, MacDill AFB, pers. comm. 01/14/15). The dredged material will be piped via floating or submerged pipeline from the dredging operation to the shoreline. The pipeline will span overland for approximately 30 feet. The dredged sediment will be transported along the pipe in a slurry of approximately 4 parts water to 1 part sediment to the existing upland disposal area located 650 feet west of the Family Campground Entrance (MacDill AFB 2014).

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Exhibit 1-3. The Beach Area Adjacent to the Navigation Channel Complex, MacDill AFB. Sheet Piling Is Proposed for Upland Installation at the Westernmost Tip of the Beach Area (the red circle indicates the general location of upland installation). Source of aerial: Google Maps

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Exhibit 1-4. Plan View Drawing of the Proposed Sheet Piling to be installed at the Westernmost Tip of the Beach Area. Source: Modified from sheet C-401 of engineering drawings dated 05/15/15 .

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Exhibit 1-5. Cross Section Drawing of the Proposed Sheet Piling to be installed at the Westernmost Tip of the Beach Area. Source: Modified from sheet C-313 of engineering drawings dated 05/15/15.

1.3 History of Consultation During correspondence between the U.S. Army Corps of Engineers (USACE) Tampa Office and the U.S. Fish and Wildlife Service (USFWS) St. Petersburg office in April 2015, USFWS expressed concern for possible effects to the rufa red knot (Calidris canutus rufa) by activities associated with the proposed maintenance dredging of the MacDill AFB navigation complex. The main concerns of USFWS were the possible disturbance by dredging activities and the proposed placement of a sheet pile in sandy upland habitat. The result of correspondence between USACE and USFWS was the mutual agreement that an Endangered Species Act of 1973 (ESA) (16 U.S.C. §§1531–1533) Section 7 consultation should be initiated to discuss and evaluate possible adverse effects of the proposed project on the rufa red knot.

1.4 Protected Species of Consideration The rufa red knot is protected by both the Migratory Bird Treaty Act and the ESA as a threatened species (USFWS 2014), including any future designated critical habitat, and is of interest to this biological assessment (BA). The red knot is known to occur at MacDill AFB according to data obtained from the eBird online database and from discussions with birders (see subsection 2.3.1 of this document).

1.5 Regulatory Framework 1.5.1 National Environmental Policy Act of 1969 (NEPA) NEPA is an important part of the decision-making process for actions involving federal lands. The NEPA process mandates federal agencies to prepare an environmental assessment (EA) or

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an environmental impact statement (EIS) designed to explain possible effects of the proposed actions on the human environment, including alternative actions and no action, and allow the public to comment. Significant impacts can result from cumulative actions and can affect unique or endangered resources. The EA or EIS is to be prepared as soon as an agency has a proposed goal (Council on Environmental Quality [CEQ] §1508.23) during the proposal stage of the federal action. An EA is produced if the impacts of a given action are unknown (CEQ §1507.3 and §1508.9). The result of drafting an EA may be a Finding of No Significant Impacts (FONSI) (CEQ §1508.13) or a finding of significant impacts, which mandates the production of an EIS (CEQ §1501.4 and §1507.3). NEPA is procedural only and is designed to prevent uninformed decisions but does not force any particular action.

1.5.2 Endangered Species Act of 1973 The ESA was designed to protect imperiled species from extinction due to economic growth and development. ESA Section 7, Interagency Coordination, is of interest to this BA. It regulates all federal agencies to protect endangered and threatened species and their designated critical habitat.

ESA Section 7(a)(2) states that agencies shall, in consultation with the Secretary of the Interior or the Secretary of Commerce (depending on the species in question), ensure that any action is not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of critical habitat unless the agency was granted an exception for the action by the Endangered Species Committee (ESA §7(h)).

A formal consultation with the secretary is conducted to obtain a written Biological Opinion and a summary of information on which the opinion is based showing how the agency action affects the species or its critical habitat (ESA §7(b)(3)(a)). If the action is found to put the species in jeopardy or to adversely modify critical habitat, the secretary will suggest reasonable and prudent alternatives, which will not violate ESA Section 7(a)(2), to be taken by the agency in implementing the action.

An informal consultation (BA) with the secretary is conducted if the agency has reason to believe that an endangered or threatened species or designated critical habitat may be present in the area affected by the project and that the implementation of the proposed action is likely to affect such species or habitat (ESA §7(a)(3)). The results of a literature review on the red knot at MacDill AFB are incorporated into the ESA Section 7 consultation as part of this BA.

1.5.3 Migratory Bird Treaty Act of 1918 Executive Order 13186, published in January 2001, asserts that the protection of migratory birds is the responsibility of federal agencies. Also, a memorandum of understanding between the Department of Defense and USFWS, signed in July 2006, states that the Department of Defense shall take steps to manage and mitigate potential impacts on migratory birds, such as identifying the species likely to occur in the area of the proposed action and assessing the potential impacts to migratory species using best-available data.

The red knot is among the majority of bird species occurring within the United States and its territories that are afforded protection under this statute. The statute makes it unlawful to pursue, hunt, take, capture, kill, or sell (whole or parts, live or dead) any of the over 800 species of birds covered under the act. A complete list of species covered can be found at http://www.fws.gov/migratorybirds/RegulationsPolicies/mbta/mbtandx.html.

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2 THE RED KNOT The genus Calidris is derived from the Greek ‘kalidris’, a reference to beach-inhabiting birds. The specific epithet canutus is a Latin reference to the gray plumage. The sub-specific epithet rufa is from the Latin rufus meaning reddish (Jaeger 1944). The subspecies C. c. rufa was originally described as the species Tringa rufa by the Scottish-American naturalist Alexander Wilson in an 1813 publication and was based on specimens from New Jersey (Conover 1943). Six subspecies are currently recognized based on body size, plumage characteristics, and separate breeding areas (Niles et al. 2008). The rufa red knot (Calidris canutus rufa) of Tierra del Fuego through the central Canadian Arctic is the subject of this BA. The remaining five subspecies consist of C. c. islandica of the Atlantic coast of Europe west to the Canadian High Arctic and in Greenland, C. c. piersmai of northwestern Australia through north-central Russia, C. c. rogersi of Australia and New Zealand through eastern Russia, and C. c. roselaari of northwestern Mexico through northern Alaska. An additional, nominal subspecies C. c. canutus is believed to range from southwestern Africa through western Siberia (Committee on the Status of Endangered Wildlife in Canada [COSEWIC] 2007). Red knots overwintering or stopping-over in Florida are believed to consist of one or both of the subspecies C. c. rufa and C. c. roselaari (COSEWIC 2007). Until taxonomic uncertainties are resolved, the possibility remains that the Florida overwintering and stopping-over populations of red knots can only be assumed to include numbers of C. c. roselaari and (or) the rufa red knot (e.g., Niles et al. 2008). It has even been suggested by Niles et al. (2008) that red knots in Florida may represent an as-yet-undescribed subspecies.

For the purposes of this BA, unless otherwise stated, the sub-specific identity of red knots overwintering and stopping-over in Florida is assumed to consist wholly or mainly of rufa red knots. This is to simplify the treatment of this threatened species and to ensure that appropriate conservation measures are taken, when and if appropriate, in the event that the red knots of Florida are later determined to be rufa red knots based on detailed scientific analysis.

2.1 Description In Florida during winter, adults appear light gray with slight mottling. In summer, adult plumage appears brighter in color and with a robin-like rusty breast area (Maehr and Kale II 2005). The body shape is rather robust compared to most other sandpipers. The eye color is black. The bill and short legs are dark gray to black. While in flight, the red knot shows a whitish rump finely barred with gray (National Geographic Society 1992). Exhibit 2-1 shows the characteristics of a non-breeding adult red knot from Sanibel Island, Florida.

The red knot lacks obvious sexual dichromism; however, sexual dimorphism is apparent with females, which have a higher average body mass and longer bill length than males (Niles et al. 2008). Adult red knots measure about 25 to 27 cm in length (National Geographic Society 1992, Maehr and Kale II 2005). Adult males have a mean body mass of 126.0 g (range: 112.0 to 136.0 g, n = 13), while the average weight of adult females is 148.0 g (range: 135.0 to 169.0 g, n = 9) based on a population sampled in northern Canada (Parmelee and MacDonald 1960). Body mass probably changes significantly with seasons, with reproductive status, and in relation to migratory activities.

It is difficult to differentiate the two possible subspecies living in Florida simply by viewing them in the wild, and it is unclear whether any detailed morphological comparison has been made

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between C. c. rufa and C. c. roselaari (Niles et al. 2008). The subspecies-level differences are largely confined to plumage and relative size during breeding (Niles et al. 2008). Due to the difficulties in differentiating these two subspecies when overwintering, most Florida guidebooks do not attempt to address subspecies differences.

Exhibit 2-1. Adult Red Knot in Non-breeding Plumage, Sanibel Island, Florida Source: D. Daniels and Wikimedia Commons

2.2 Range and Populations The rufa red knot spends the spring and summer months breeding in Alaska, although the specific breeding area has not yet been confirmed (Niles et al. 2008). The winter months are spent along coastal intertidal and roosting areas of the United States, Mexico, Central America, and South America (National Geographic Society 1992, COSEWIC 2007). Some populations migrate as far south as southern Patagonia and Tierra del Fuego (Niles et al. 2008). Some juveniles (<2 years of age) don’t reach the southernmost portions of the wintering range. Individuals have a tendency to return to the same wintering grounds year after year (COSEWIC 2007).

Population estimates based on censuses undertaken at wintering grounds are considered the most reliable estimates available. The total population for the species as a whole was recently estimated at approximately 1,050,000 individuals worldwide (Niles et al. 2008). Estimates in the 1980s suggested a rufa red knot population of 100,000 to 150,000, including birds wintering in Florida and South America (COSEWIC 2007). A study by Morrison and Ross (1989) reported 67,500 rufa red knots for South America based on an aerial survey. By the late 1990s,

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the rufa red knot population from the southern wintering grounds in South America was estimated at closer to 60,000 (Baker et al. 2001). A census conducted in 2005 suggests that the population in the southern wintering grounds is down to 18,000 to 20,000, about 75% (13,500 to 15,000) of which are mature individuals (COSEWIC 2007). Band-recapture data during the same period were consistent with the 2005 population estimate (Gonzalez et al. 2004). The population that overwinters in Patagonia was estimated at around 17,200 individuals in 2006 (Niles et al. 2008). The largest wintering population is found in Bahia Lomas, Chile (Animal Diversity Web 2011). The overwintering population of rufa red knots along the Georgia coast can number as high as 12,000 (Georgia Wildlife 2010).

In 2007, the rufa red knot was thought to have experienced a 70% decline in abundance over the previous 15 years (COSEWIC 2007). The fact that all regions where the rufa red knot occurs have experienced similar declines over the same time period indicates an actual population decline rather than merely a redistribution of the birds (COSEWIC 2007). The entire population of rufa red knots was estimated in 2008 as 18,000 to 35,000 individuals (Niles et al. 2008). The population of rufa red knots that overwinter along the southeastern United States was estimated in 2005 at 15,000 to 20,000 individuals according to Baker et al. (2005).

2.2.1 Populations in Florida The overwintering population along Florida’s Gulf coast was estimated at 10,000 in the late 1980s by Harrington et al. (1988). Shorebirds were surveyed from November 1993 through March 1994 by Sprandel et al. (2000) at 60 sites along Florida’s Gulf coast. These authors observed an average of 380 individuals, and a maximum number of 775 individuals, at Shell Key Preserve in St. Petersburg. An average of 3,523 individual red knots were observed by these authors among the 60 sites surveyed along Florida’s Gulf coast.

Red knots were the seventh most abundantly observed species of shorebird statewide during the winter of 1993–1994 according to a 1998 unpublished report by G. Sprandel (Florida Game and Freshwater Fish Commission, Quincy, FL). The population overwintering in Florida fluctuates from year to year, apparently based on invertebrate prey abundance (Niles et al. 2008).

A population of 3,375 individuals was estimated in the late 2000s for individuals overwintering in Florida and the southeastern United States (COSEWIC 2007). These authors attributed this population to the subspecies C. c. roselaari (COSEWIC 2007). However, it remains unclear whether the red knots in Florida consist of or include this subspecies (Niles et al. 2008). The most recent data available on red knots along Florida’s Gulf coast, based on a census in November 2004, puts the overwintering population at 4,000 to 5,000 individuals and a total population of 7,500 individuals overwintering in the state as a whole (Niles et al. 2008). This estimate is not considered to be highly reliable and should be treated with caution (Niles et al. 2008).

The red knots overwintering in Florida apparently move between Florida and Georgia based on the availability of resources such as prey abundance (Niles et al. 2008). The census data vary greatly from year to year, probably due to the difficulty in surveying along the many barrier islands and fragmented coastline. The current population appears to be of the same order of magnitude as it was during the 1980s according to Niles et al. (2008). However, overall, the decline in Florida’s overwintering population is estimated at 11% to 33% during the mid- to

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late-2000s (Niles et al. 2008). Exhibit 2-2 shows the results of winter bird counts along Florida’s Gulf coast during a 3-year period.

Exhibit 2-2. Counts of Red Knots along Florida’s Gulf Coast over a Period of Three Winters (2004–2008). Winter of 2005–2006 Winter of 2006–2007 Winter of 2007–2008 2,500 1,200 550

Source: Table 39 of Niles et al. (2008).

2.3 Seasonality and Habitat Use in Florida The red knot overwinters in Florida (Longstreet and Grimes 1969, Robertson, Jr. and Woolfenden 1992), although some populations use Florida merely as a stopover on their way to more southerly destinations (Niles et al. 2008) (Exhibit 2-3). Individuals undergoing migration can be seen in Florida beginning in August (for fall migration) and again in April or May (for spring migration) (Cunningham 1961, Maehr and Kale III 2005). The species may be more commonly observed in Florida during April and late August through October than during other months (Lane 1981). However, some individuals remain in the state through summer (Maehr and Kale III 2005), and red knots have been observed in Florida in all months of the year (Niles et al. 2008). The species is seen probing for food with other shorebirds on Gulf and Atlantic beaches, on mudflats, and in marshes (Cunningham 1961, Maehr and Kale III 2005). The primary habitats used by red knots in Florida consist of sandy beaches, tidal mudflats, saltmarshes, brackish lagoons or impoundments, and mangrove forests (Niles et al. 2008). In Florida, red knots feed on small infaunal and epifaunal invertebrates such as estuarine aquatic insect larvae, polychaete worms, small mollusks, and small crustaceans (Longstreet and Grimes 1969). Its primary food sources along Florida’s beaches are the dwarf surfclam (Mulinia lateralis) and the variable coquina (Donax variabilis) (Maehr and Kale III 2005, Niles et al. 2008). Nearly all feeding in Florida is conducted in intertidal habitats, particularly on mudflats and beaches (Niles et al. 2008). The species is rarely seen in inland Florida (Robertson, Jr. and Woolfenden 1992, Maehr and Kale III 2005).

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Exhibit 2-3. Red Knot Habitat Usage per State in the Eastern U.S. Florida Is Both an Overwintering Area and a Stopover for the Species. Source: Modified from Figure 52 of Niles et al. (2008)

Red knots occur more often in central and southern Florida than in northern Florida or in the Florida Keys (Lane 1981). The center of abundance in Florida is a 300-km-long stretch of Gulf coastland between Anclote Key (Pinellas County) and Cape Romano (Collier County) (Niles et al. 2008). Specific localities known to harbor red knots are listed in Exhibit 2-4. The abundance (n/checklist) of red knots reported to eBird for Hillsborough County is shown in Exhibit 2-5.

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Exhibit 2-4. Observations of the Red Knot during Four Bird Counts from December 1993 through March 1994 at 23 Sites in Florida, in Decreasing Order of Maximum Number Recorded Count Count Site (minimum) (maximum) Shell Key 113 775 Caladesi Island, Hurricane Pass 6 300 Passage Key 0 300 Capri Pass (Key Island) 31 286 Island north of Bunces Pass (now contiguous with Shell Key) 0 280 Little Estero Island 0 241 Palm Island Resort 51 223 Caladesi Island, Dunedin Pass 0 165 Merritt Island NWR, Black Point Drive 0 164 Lanark Reef 1 147 Honeymoon Island 31 122 Lake Ingraham (SE end) 0 122 Yent Bayou 0 116 Three Rooker Bar (N and S ends) 0 79 Carrabelle Beach 0 69 Anclote Key (N and S ends) 0 64 Snake Bight Channel 0 60 Courtney Campbell Causeway SE (2 sites) 0 39 Ding Darling NWR (obs. Tower) 0 30 Ft. DeSoto (NW end) 0 7 Lido Beach 0 7 Ft. DeSoto (E end) 0 2 Kennedy Space Center (Pad 39B) 0 2 Source: Table 22 of Niles et al. (2008).

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Exhibit 2-5. Abundance (n/checklist) of Red Knots per Week in Hillsborough County, Florida, Based on Data Reported to eBird. Source: eBird data query on 05/14/15 at http://ebird.org/ebird/GuideMe?step=saveChoices&getLocations= counties&parentState=US-FL&speciesCodes=redkno&bMonth=01&bYear=1900&eMonth=12&eYear=2015& reportType=species&counties=US-FL-057&continue.x=62&continue.y=9&continue=Continue

Red knots occurring at MacDill AFB and elsewhere in Florida (as well as in Georgia, South Carolina, and Texas) are not necessarily the rufa red knot, as subspecific status of the Florida population remains uncertain (Niles et al. 2008). As previously stated in this BA, the Florida population may contain either or both of C. c. rufa and C. c. roselaari subspecies (e.g., Niles et al. 2008).

2.3.1 Sightings and Habitat Use at MacDill AFB The red knot was observed during multiple occasions at MacDill AFB. From November 2011 to the date of writing (05/11/15), a total of 128 sightings were recorded at MacDill AFB based on a query of the eBird online database (http://eBird.org/content/eBird/) conducted 05/11/15. More sightings were recorded during November 2014 (74 sightings) than in any other month. No sightings were listed prior to that month. The last sighting reported to the eBird database was on March 24, 2015. Since most sightings were conducted while traveling between 4 and 10 miles, the exact area where the sightings could not be determined from the eBird database. All sightings at MacDill AFB are spatially indicated in eBird as taking place at the Bay Palms Golf Complex approximately 1.2 miles northeast of the proposed location of the sheet piling and approximately 1 mile north of Basin A, and outside of the project area. The spatial data in eBird appears to be misleading based on an interview with Ms. Sandra Reed of the Tampa Audubon Society on 05/18/15. The eBird spatial data for MacDill AFB may be meant to show only the general association between the birds sighted and MacDill AFB as a whole rather than

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to show particular habitat usage (see the following paragraph regarding information provided by Ms. Reed). Exhibit 2-6 lists all sightings of red knots at MacDill AFB reported to eBird as of this writing. Exhibit 2-7 shows the misleading spatial location associated with all checklists reported to eBird from MacDill AFB.

Exhibit 2-6. Summary of All Sightings of Red Knots at MacDill AFB Reported to eBird to 05/11/15. Number of Red Date Observer Notes Knot Sightings

24-Mar-2015 Sandra Reed Traveling 4 miles over 5 hrs & 20 min. 3

30-Nov-2014 Sandra Reed Traveling 10 miles over 5 hrs 10

21-Nov-2014 Sandra Reed Traveling 10 miles over 4 hrs 20

21-Nov-2014 Tammy Lyons Traveling 10 miles over 4 hrs & 30 min. 8

Mark Fears, Susan Fears, Gary-Janice Sortor, Ruth Jones, 01-Nov-2014 Thomas Farrell, Traveling 15 miles over 6 hrs 36 Linda Schocken, Marilyn Grossman, and Sandra Reed

27-Sep-2014 Sandra Reed Traveling 4 miles over 3 hrs 6

11-Aug-2014 Sandra Reed Traveling 5 miles over 5 hrs 5

07-Aug-2014 Sandra Reed Stationary over 45 min. 11

14-May-2013 Sandra Reed Traveling 5 miles over 2 hrs & 30 min. 3

14-May-2013 Tammy Lyons Traveling 5 miles over 2 hrs & 30 min. 3

11-Nov-2011 Sandra Reed Traveling 7 miles over 2 hrs & 30 min. 23 TOTAL = 128 Mean = 14.2/day RANGE = 3−36 PEAK MONTH =

November (74 sightings) Source: Online query of eBird online database on 05/11/15 (http://eBird.org/eBird/map/redkno?bmo=&emo=&byr=&eyr=&env.minX=-82.551&env.minY=27.803&env.maxX=- 82.451&env.maxY=27.903&gp=true).

16 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-7. Checklists Submitted to eBird for MacDill AFB Reference This Geographic Locality (indicated by a red circle). (However, this information appears misleading based on information provided by Ms. Sandra Reed of the Tampa Audubon Society.) Source: Modified from eBird spatial data provided at (http://eBird.org/eBird/map/redkno?bmo=&emo=&byr=&eyr=&env.minX=- 82.551&env.minY=27.803&env.maxX=-82.451&env.maxY=27.903&gp=true)

Of the 11 checklists submitted to eBird that included red knot sightings at MacDill AFB, 9 (82%) were conducted or lead by Ms. Sandra Reed of the Tampa Audubon Society. Ms. Reed was contacted on 05/18/15 by the ANAMAR staff biologist for information on habitat usage at the base. Ms. Reed discussed three main areas where she has seen red knots on the base: 1) A large mudflat east of the security gate along Bayshore Boulevard. Birds can be seen here mostly coinciding with low tide (Exhibit 2-8). 2) An armored section of shoreline near a pavilion and south of two docks, east of Bayshore Boulevard (Exhibit 2-9). 3) The beach area between the main marina and Seascapes Beach House restaurant (Exhibit 2-10). Red knots in this area are seen near the water’s edge. Behaviors of red knots indicate that the area is used for foraging as well as for roosting. More red knots were observed here during adverse weather (when there was little or no human activity on the beach) than during times of high human activity.

Horseshoe crabs (Limulus polyphemus) have also been observed by Ms. Reed within the riprap south of the two docks and east of Bayshore Boulevard. Horseshoe crab eggs have been observed by Thomas Farrell along the section of shoreline east of Bayshore Boulevard during

17 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

March and April (Farrell 2010; T. Farrell, USACE Jacksonville District [retired], pers. comm., 05/18/15). However, the armoring along this section of shoreline has been enhanced since that time, and it is not known if horseshoe crabs can still successfully spawn there.

Exhibit 2-8. A Large Mudflat (indicated by a red circle) Is Exposed during Low Tide East of the Security Checkpoint along Bayshore Boulevard. Red Knots Have Been Observed Using This Mudflat. Source: S. Reed, Tampa Audubon Society, pers. comm., 05/18/15

18 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-9. Red Knots Have Been Observed Using an Armored Section of Shoreline (indicated by a red circle) East of Bayshore Boulevard. Horseshoe Crabs Have Been Observed along This Section of Armored Shoreline As Well. Sources: S. Reed, Tampa Audubon Society, pers. comm., 05/18/15; T. Farrell, USACE Jacksonville District (retired), pers. comm. 05/18/15.

19 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-10. Red Knots Have Been Observed along the Beach Area of MacDill AFB, near the Water’s Edge (indicated by a red circle). Observed Behaviors Consisted of Both Roosting and Foraging. Horseshoe Crabs Were Observed in the Spring of 2008 at the Western Tip of the Beach Area (blue circle). Sources: S. Reed, Tampa Audubon Society, pers. comm., 05/18/15; T. Farrell, USACE Jacksonville District (retired), pers. comm., 05/18/15

The beach area along the southern tip of the base appears to be anthropogenically maintained to prevent it from reverting back to the mangrove-dominated habitat that exists west and east of this area (Exhibit 2-11). Maintenance activities include regular beach raking according to Ms. Reed. This area may have been converted from mangroves or similar vegetated riparian habitat in the early 1940s, when sand may have been pumped onto this area during the original dredging event. The 1969 dredging of Channel B was a way of improving the swimming area associated with this beach (Tampa Port Authority 2003). A shallow seagrass flat exists in front (south) of the beach area, on the opposite side of Channel B. It is unclear whether the beach area includes the important attributes of natural beaches, such as high-energy wave action, which would normally deliver nourishment and highly oxygenated water to infaunal aquatic mollusks such as the dwarf surfclam and the variable coquina. These organisms would need to occur in high enough densities along the beach area of the base to provide suitable forage for red knots because prey availability is the most important characteristic of overwintering habitat for red knots (Niles et al. 2008). Thus, the beach area may or may not provide suitable foraging opportunities to red knots. The species was repeatedly observed along the water’s edge at the beach area on several occasions (not all of which were reported to eBird). It is unknown whether this area acts as a benefit for foraging red knots or if the species is simply lured there by the appearance of suitable habitat only to find unsuitable food despite foraging effort. The beach area appears suitable for roosting of red knots, although the birds may be

20 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

disturbed by humans using the area for recreation and by beach-raking activities, according to Ms. Reed and based on documented effects in other areas.

Exhibit 2-11. The Beach Area (indicated by a red circle) at MacDill AFB Is Bordered by Mangrove Swamp Habitat (shown in pink) to the West and East, Indicating That the Beach Area Was Once Also Mangrove Habitat. Source: Modified from Figure 2 of USAF (2012)

It is possible that horseshoe crabs use the beach area for spawning and may therefore provide some sustenance to the red knot in the form of eggs. In Florida, horseshoe crabs spawn year- round with a peak from March through May (Gerhart 2007). Spawning is synchronized with the lunar cycle, especially with spring tides (the highest tide of a given month), but this is not valid for all areas of the western Atlantic. Mr. Farrell has observed horseshoe crabs near the western tip of the beach area, near Channel B, during March or April 2010 (Exhibit 2-10). A photo taken by retired Sergeant Daniel Wilcox shows a spawning aggregation of horseshoe crabs at this western tip of the beach on April 11, 2008 (Exhibit 2-12). It appears that at least some horseshoe crab spawning activity occurs at the beach area at MacDill AFB, at least during April. However, since most sightings of red knots at the base occurred during November and outside of the peak spawning season of the horseshoe crab, it is unclear whether this possible food source plays a significant role in attracting and retaining red knots at MacDill AFB. The temporal periodicity of red knot sightings at MacDill AFB may be a reflection of human effort rather than a true reflection of relative presence and absence of the species. Bird observation

21 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

effort peaks in November and December in many areas of Florida, coinciding with annual bird counts organized by local chapters of the National Audubon Society.

No red knot sightings were recorded incidental to the several surveys for threatened and endangered species, including shorebirds, at MacDill AFB that occurred from November 2011 to March 2012 (USAF 2012). A Florida Natural Areas Inventory Biodiversity Matrix query conducted on 05/11/15 for the 1-square-mile matrix unit 25235 (including the beach area) revealed that no red knots have been documented, are likely to occur, or could potentially occur in the area (http://data.labins.org/mapping/FNAI_BioMatrix/GridSearch.cfm?sel_id=25235& extent=548379.5,424804.03125,549988.875,426413.40625). This may be due to the relatively recent listing of the rufa red knot as the Florida Natural Areas Inventory may not have had time to update their database to reflect the recently enhanced conservation interest for this taxon.

22 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-12. Horseshoe Crab Spawning Aggregation at the Western Tip of the Beach Area, Photographed on April 11, 2008. Sources: Photographed by Sergeant Daniel Wilcox (retired); photo courtesy of T. Farrell, USACE Jacksonville District (retired)

2.4 Threats to Red Knots in Florida Habitat alteration is considered the primary threat to overwintering populations of red knots in Florida. Shoreline hardening, dredging activities, beach renourishment, and beach raking continue to alter Florida’s coastal habitats. The placement of sand onto beaches can reduce populations of important infaunal prey items (including the variable coquina and dwarf surfclam) which may reduce the value of these beaches to foraging red knots and other shorebirds (Cohen et al. 2009). Beach renourishment activities along Florida beaches, including those along Fort Myers and Estero Island, are thought to decrease the availability of beach

23 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

infaunal prey items available to red knots and therefore displace overwintering red knots to more productive foraging areas elsewhere in Florida and Georgia (Niles et al. 2008). In general, any human activity that significantly alters the natural characteristics of the beach zone may be a threat to red knots. However, the extent to which these activities effect red knots and other shorebirds is poorly known but thought to be significant (Niles et al. 2008).

In addition to habitat alteration, chronic disturbances by humans is an important threat to red knots in Florida (Niles et al. 2006) and include most forms of beach activities. Virtually all foraging habitat and most roosting sites are located in areas of constant recreational activities. Although many coastal habitats important to red knots are public lands, many are not actively managed. Very few lands are managed in any way to accommodate the needs of overwintering birds or species using the area as a stopover, although some sites receive incidental protection while being managed for beach-nesting birds, to protect seagrass beds, or for homeland security restrictions as military installations (Niles et al. 2008). Management measures meant for beach-nesting birds offer little or no incidental protection for the red knot considering that most red knots are in northern locales during summer months.

Although horseshoe crab eggs may not be as important a food item in Florida as it is in other areas (such as in Delaware Bay [Niles et al. 2008]), the possible decline of this energy-rich source may be considered a threat, particularly to red knots using Florida as a stopover on their way to overwintering areas in South America.

Reduced population size may make the red knot more susceptible to stochastic events. Given the strong dependence on coastal habitats exposed to potential storm events and oil spills, and the tendency to aggregate over a relatively few number of sites, this should come as no surprise. Reduced population size may further jeopardize the species by effectively reducing genetic variability. If the total population were to drop below approximately 10,000 individuals, genetic variability would be greatly hindered according to Baker et al. (2005). This is because only a portion of a population successfully rears offspring and thus contributes to the gene pool. In addition to the added risk from stochastic events, reduced genetic variability equates to increased susceptibility to harmful genetic mutations and reduced ability to bounce back from disease outbreaks.

2.5 Conservation and Protection The rufa red knot is protected by the Migratory Bird Treaty Act and the ESA as a threatened species (USFWS 2014). Although not currently protected by Florida law (FWC 2013, https://www.flrules.org/gateway/result.asp), the red knot is afforded some protection by local government and non-profit groups. These protections consist mostly of attempts to reduce human disturbances to foraging and roosting red knots. Areas of Florida where red knots are afforded protections from disturbance are listed in Exhibit 2-13.

24 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-13. Areas of Florida Affording Protection to Red Knots from Chronic Disturbance by Humans Area Protection GULF COAST Shell Key Portions of the island are closed to entry

Caladesi Island, Hurricane Pass Limited posting of signage at a roosting area

Passage Key Closed to entry (however, poorly enforced)

Anna Maria Island Posting of signage at roosting area, roped-off area

Ding Darling NWR (obs. Tower) Restricted access ATLANTIC COAST Little Talbot Island State Park Posting of signage at roosting area, roped-off area

Merritt Island NWR (Black Point Drive) Restricted access

Kennedy Space Center Limited access

Sources: Page 117 of Niles et al. (2008), Audubon of Florida accessed online 05/14/15 at http://fl.audubonaction.org/site/MessageViewer?em_id=12841.0&printer_friendly=1.

The target wintering population size for rufa red knots in Florida proposed by Niles et al. (2008) is between 20,000 and 25,000 individuals with an over-arching goal of achieving a total population size (throughout the flyway) of 100,000 to 150,000. The goal for the total population size is based on the estimated number of rufa red knots that occurred more than 25 years ago. This information may be among those considered by USFWS as the agency begins to draft a recovery plan and delisting criteria.

2.5.1 Critical Habitat Critical habitat for the rufa red knot has not yet been identified by USFWS according to a press release dated 12/09/14 (http://www.fws.gov/news/ShowNews.cfm?ID=306702E2-C4DB-EDF8- 28653BB2E2D600F5) and USFWS (2014). USFWS identified counties in Florida where red knots are known or are believed to occur. However, Hillsborough County was not among those listed as of 05/08/15 (http://ecos.fws.gov/speciesProfile/profile/countiesByState?entityId=8621&state =Florida). Critical habitat designation and the outlining of a recovery plan are likely being undertaken by USFWS.

Although no official critical habitat has yet been designated for protection under the ESA, an authoritative attempt at identifying critical habitat was undertaken by Niles et al. (2008). These authors identified critical habitat for the rufa red knot based on (1) sites of known importance to the subspecies and documented by survey data, (2) sites of known importance based on expert opinion (with or without survey data), and (3) sites of known importance that are occupied intermittently (because of natural fluctuations, human disturbance, beach renourishment) and may or may not have survey data. MacDill AFB is not contained within any critical habitat as determined by Niles et al. (2008). Exhibits 2-14 through 2-16 show critical habitat in Florida as determined by these authors.

25 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-14. Unofficial Critical Habitat for the Red Knot in Florida as Described by Niles et al. (2008) Source: Modified from Map 11 in Niles et al. (2008)

26 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-15. Unofficial Critical Habitat for the Red Knot in Northern Florida as Described by Niles et al. (2008) Source: Modified from Map 12 in Niles et al. (2008)

27 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

Exhibit 2-16. Unofficial Critical Habitat for the Red Knot in Southern Florida as Described by Niles et al. (2008). MacDill AFB Is Not Considered Critical Habitat by These Authors. Source: Modified from Map 13 in Niles et al. (2008)

28 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

2.6 Discussion The beach area adjacent to the proposed dredging area is apparently suitable for foraging and (or) roosting based on the literature review and interviews conducted for this BA (see Subsection 2.3.1 for a summary of sightings at MacDill AFB). At least some of the 128 sightings of red knots at MacDill AFB reported to eBird to-date have occurred at this beach area. Although the sheltered, low-energy characteristics of this beach area may not harbor significant densities of variable coquinas or surfclams on which these birds primarily feed, the presence of spawning aggregations of horseshoe crabs suggest that eggs may be available to red knots, at least during spring. However, the majority of red knots were observed during November, outside of the peak spawning season of the horseshoe crab in Florida.

2.6.1 Potential Threats to Red Knots The red knots utilizing the beach area at MacDill AFB are apparently affected by human disturbance based on the observations of Ms. Reed and the known effects of human disturbance elsewhere in its range. Recreational and beach-raking activities may affect this species, as evidenced by the negative correlation between numbers of red knots observed at the beach area relative to the level of human activity there. The enhancement of shoreline armoring in recent years along the eastern edge of the base, east of Bayshore Boulevard, may have reduced the suitability of this habitat for red knots and reduced or eliminated the ability of horseshoe crabs to spawn there.

29 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

3 EFFECTS ANALYSIS OF PROPOSED ACTION Based on negative effects for the rufa red knot as discussed in Niles et al. (2008), and taking into account human activities at MacDill AFB, potential risk factors associated with the proposed maintenance dredging and the installation of a sheet piling include: • Chronic human disturbance during roosting • Habitat alteration that negatively affects prey abundance • Habitat alteration that negatively affects foraging and (or) roosting opportunities

3.1 Red Knots Based on the habitat characterization and results of recent surveys, it is determined that the red knot utilizes the beach area of MacDill AFB, although only low numbers have been observed there at any one time. The low numbers of this species minimize the chances of disturbance to foraging or roosting red knots during the maintenance dredging and installation of the proposed sheet piling at the far west end of the beach area.

For this reason, the proposed action is not likely to adversely affect rufa red knots. This includes both initial impacts (construction phase) and cumulative impacts (long-term effects of the sheet piling). Any effects are considered to be insignificant due to the relatively small area of installation and dredging activity combined with the low numbers of red knots recorded from MacDill AFB. The Endangered Species Consultation Handbook by USFWS and National Marine Fisheries Service (NMFS) (1998) defines insignificant effects as those which cannot be meaningfully measured, detected, or evaluated using best judgment.

3.2 Critical Habitat Although USFWS has yet to designate critical habitat, Niles et al. (2008) identified habitat they considered critical to the rufa red knot based on (1) sites of known importance to the species and documented by survey data, (2) sites of known importance based on expert opinion (with or without survey data), and (3) sites of known importance that are occupied intermittently (because of natural fluctuations, human disturbance, beach renourishment) and may or may not have survey data (Niles et al. 2008). The critical habitat identified did not include MacDill AFB. Because MacDill AFB is excluded from this unofficial yet authoritative critical habitat as determined by Niles et al. (2008), this proposed action is not likely to adversely affect rufa red knot critical habitat. The proposed conservation measures would limit any potential project- related effects.

3.3 Conservation Measures The potential effects on rufa red knots and other overwintering shorebirds due to construction activities is likely to be insignificant relative to the current impacts from disturbance by recreational activities and beach raking. Only low numbers of red knots (mean: 14.2 individuals/survey day, maximum: 36 individuals/survey day) have been observed at a time anywhere at MacDill AFB. The total number of red knots observed at MacDill and reported to eBird (n = 128) amounts to less than 2% of the total current population for the entire state (N = 7,500) as estimated by Niles et al. (2008). No red knots have been sighted at the western tip of the beach (the area proposed for sheet piling installation). Further, it remains unclear if the MacDill population includes the threatened rufa subspecies.

30 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

It may be suggested by USFWS that project activities should occur only during high tide to avoid prime foraging periods of the birds. It may also be suggested that dredging in front of the beach area should only be scheduled for May through July to avoid the migratory and overwintering season altogether. These arguments may hold some truth. However, although these methods may seem practical in print, they are impractical from a construction logistics standpoint. These conservation measured may significantly delay the project start and restrict work periods. The construction timeline is likely to increase as a result of these measures and this would in-turn increase project costs. Further, any delay or extension in the maintenance dredging activities due to conservation measures may impede the necessary enforcement of the marine exclusion zone. Since only low numbers of red knots utilize the base, and the birds may already be disturbed by other human activities on the beach, the conservation benefits of these measures to the rufa red knot are unclear and are unlikely to offset the increased logistical cost to the project. These measures may also impede critical patrolling and enforcement at MacDill. For these reasons, it is suggested that the above-mentioned potential conservation measures are unnecessary.

The following conservation measure is suggested to ensure that the rufa red knot is not significantly impacted by the proposed maintenance dredging activities. The construction zone and associated entry/exit route should be demarcated so that these activities are restricted to a ‘designated area’. The designated construction area can be surveyed periodically for red knots by a qualified biologist using a spotting scope or high-powered binoculars. If the species is observed within the designated area, construction activities should be halted until the red knots have left the area. Numbers of red knots can be noted along with their activity and the information passed on to USFWS and reported to eBird. This will ensure that the rufa red knot is not significantly impacted by the proposed maintenance dredging.

31 Biological Assessment of Potential Impacts to the Red Knot at MacDill AFB

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Niles, L.J., H.P. Sitters, A.D. Dey, P.W. Atkinson, A.J. Baker, K.A. Bennett, R. Carmona, K.E. Clark, N.A. Clark, C. Espoz, P.M. Gonzalez, B.A. Harrington, D.E. Hernández, K.S. Kalasz, R.G. Lathrop, R.N. Matus, C.D.T. Minton, R.I.G. Morrison, M.K. Peck, W. Pitts, R.A. Robinson, and I.L. Serrano. 2008. Status of the Red Knot (Calidris canutus rufa) in the Western Hemisphere. Studies in Avian Biology No. 36, Cooper Ornithological Society, Department of Biology, University of California, Riverside, CA.

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