Importance of Stewards and Other Protection Efforts for Conservation of Red Knots (Calidris canutusrufa) and Other Shorebirds on Delaware Bay, New Jersey
Understanding the factors that contribute to population stability in long-distance migrant birds is increasingly important, particularly given global climate change, sea level rise, and loss or disturbance at essential habitats. While the populations of most shorebirds are declining worldwide, those that migrate through Delaware Bay, New Jersey and Delaware, are declining at the most rapid rate despite conservation efforts. In this paper, we 1) provide background information on population declines of red knots (Calidris canutusrufa) using Delaware Bay, threats to their foraging, and efforts to reduce threats, 2) summarize briefly our studies of the effects of human activities on knots and other shorebirds, 3) present data on management efforts to protect knots and other shorebirds from the activities of people, and 4) discuss the efficacy of such efforts (usually referred to as “decreasing the effect of human disturbances”). The Shorebird Project on Delaware Bay is over 25 years old and provides long-term data to help assess the status of shorebird numbers, particularly for red knot, as well as the density of horseshoe crabs (Limulus polyphemus) and their eggs. Red knots have continued to decline even more precipitously in the last few years, presenting cause for concern. Protective efforts have been successful in reducing human disruption on the N.J. Delaware Bay beaches, but the lack of uniformity in implementation across the New Jersey side, and across the whole Bay have hampered further improvements. Implementation of signs, fencing, and stewards on some beaches significantly enhanced the use of these beaches by red knots, determined by examining the use of beaches pre- and post-implementation. Implementation of fencing and stewards had the greatest effect. From 1986 to 2018, there was a significant shift in the percent of Delaware Bay red knots using the NJ side, where protection efforts had been implemented on many of the beaches. Merely restricting access (without fencing or other efforts) did not result in more knots using the beaches post-restriction. This is the first paper that clearly shows the protective effects of having beach stewards. We discuss the long-term needs for continued management of Delaware Bay beaches, and other beaches coastwide, and of determining the causes of population declines of red knots.
References
[1]
Morrison, R.E.G., Aubrey, Y., Butler, R.W., Beyersbergen, G.W., Donaldson, G.M., Gratto-Trevor, Hicklin, P.W., Johnson, V.H. and Ross, R.W. (2001) Declines in North American Shorebird Populations. Wader Study Group Bulletin, 94, 37-42.
[2]
International Wader Study Group (IWSG) (2003) Waders Are Declining Worldwide. Wader Study Group Bulletin, 101/102, 8-12.
[3]
Hedenström, A. (2010) Extreme Endurance Migration: What Is the Limit to Non-Stop Flight? PLOS Biology, 8, e1000362. https://doi.org/10.1371/journal.pbio.1000362
[4]
Colwell, M.A. (2010) Shorebird Ecology, Conservation, and Management. University of California Press. https://doi.org/10.1525/9780520947962
[5]
Andres, B.A., Smith, P.A., Morrison, R.G., Gratto-Trevor, C.L., Brown, S.C. and Friis, C.A. (2013) Population Estimates of North American Shorebirds, 2012. Wader Study Group Bulletin, 119, 178-194.
[6]
Galbraith, H., Jones, R., Park, R., Clough, J., Herrod-Julius, S., Harrington, B., et al. (2002) Global Climate Change and Sea Level Rise: Potential Losses of Intertidal Habitat for Shorebirds. Waterbirds, 25, 173-183. https://doi.org/10.1675/1524-4695(2002)025[0173:gccasl]2.0.co;2
[7]
Galbraith, H., DesRochers, D.W., Brown, S. and Reed, J.M. (2014) Predicting Vulnerabilities of North American Shorebirds to Climate Change. PLOS ONE, 9, e108899. https://doi.org/10.1371/journal.pone.0108899
[8]
Goss-Custard, J.D., Triplet, P., Sueur, F. and West, A.D. (2006) Critical Thresholds of Disturbance by People and Raptors in Foraging Wading Birds. Biological Conservation, 127, 88-97. https://doi.org/10.1016/j.biocon.2005.07.015
[9]
Beauchamp, G. (2008) Risk Factors for Predation attempts by Peregrine Falcons (Falco peregrinus) on Staging Semipalmated Sandpiper (Calidris pusilla). Waterbirds, 31, 651-655.
[10]
Intergovernmental Panel on Climate Change (IPCC) (2014) Climate Change 2014: Impacts, Adaptation, and Vulnerability. Intergovernmental Panel on Climate Change IPPC. https://www.ipcc.ch/report/ar5/wg2/
[11]
Intergovernmental Panel on Climate Change (IPCC) (2021) Summary for Policymakers. Climate Change 2021: The Physical Science Basis. Contribution of Working Groups 1 to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
[12]
Burger, J. and Niles, L. (2017) Shorebirds, Stakeholders, and Competing Claims to the Beach and Intertidal Habitat in Delaware Bay, New Jersey, USA. Natural Science, 9, 181-205. https://doi.org/10.4236/ns.2017.96019
[13]
Conklin, J.R., Battley, P.F., Potter, M.A. and Fox, J.W. (2010) Breeding Latitude Drives Individual Schedules in a Trans-Hemispheric Migrant Bird. Nature Communications, 1, Article No. 67. https://doi.org/10.1038/ncomms1072
[14]
Marra, P.P., Cohen, E.B., Loss, S.R., Rutter, J.E. and Tonra, C.M. (2015) A Call for Full Annual Cycle Research in Animal Ecology. Biology Letters, 11, Article ID: 20150552. https://doi.org/10.1098/rsbl.2015.0552
Trierweiler, C., Klaassen, R.H.G., Drent, R.H., Exo, K., Komdeur, J., Bairlein, F., et al. (2014) Migratory Connectivity and Population-Specific Migration Routes in a Long-Distance Migratory Bird. Proceedings of the Royal Society B: Biological Sciences, 281, Article ID: 20132897. https://doi.org/10.1098/rspb.2013.2897
[17]
Bracey, A., Lisovski, S., Moore, D., McKellar, A., Craig, E., Matteson, S., et al. (2018) Migratory Routes and Wintering Locations of Declining Inland North American Common Terns. The Auk, 135, 385-399. https://doi.org/10.1642/auk-17-210.1
[18]
Dey, A., Niles, L.J., De-Rosa-Wilson, A., Smith, J.A., Sitters, H.P., Morrison, G., Mizrahi, D. and Watts, B. (2016) Update to the Status of the Red Knot (Calidris canutusrufa) in the Western Hemisphere, September 2016. New Jersey Department of Environmental Protection.
[19]
Mizrahi, D.S., Peters, K.A. and Hodgetts, P.A. (2012) Energetic Condition of Semipalmated and Least Sandpipers during Northbound Migration Staging Periods in Delaware Bay. Waterbirds, 35, 135-145. https://doi.org/10.1675/063.035.0113
[20]
Burger, J., Niles, L.J., Porter, R.R. and Dey, A.D. (2012) Using Geolocators to Reveal Incubation Periods and Breeding Biology in Red Knots. Wader Study Group Bulletin, 119, 26-36.
[21]
Burger, J., Niles, L.J., Porter, R.R., Dey, A.D., Koch, S. and Gordon, C. (2012) Migration and Over-Wintering of Red Knots (Calidris canutusrufa) along the Atlantic Coast of the United States. Condor, 114, 302-313.
[22]
Newstead, D.J., Niles, L.J., Porter, R.R., Dey, A.D., Burger, J. and Fitzsimmons, O.N. (2013) Geolocation Reveals Mid-Continent Migratory Routes and Texas Wintering Areas of Red Knots Calidris canutusrufa. Wader Study Group Bulletin, 120, 53-59.
[23]
Morrison, R.I.G. and Ross, R.K. (1989) Atlas of Nearctic Shorebirds on the Coast of South America (Vol. 1). Canadian Wildlife Service.
[24]
Niles, L., Burger, J., Porter, R.R., Dey, A.D., Minton, C.D.T., Gonzalez, P.M., Baker, A.J., Fox, W. and Gordon, C. (2010) First Results Using Light Level Geolocators to Tracks Red Knots in the Western Hemisphere Show Rapid and Long Intercontinental Flights and New Details on Migration Paths. Wader Study Group Bulletin, 117, 1-8.
[25]
Niles, L.J., Burger, J., Porter, R.R., Dey, A.D., Koch, S., Harrington, B., Iaquinto, K. and Boarman, M. (2012) Migration Pathways, Migration Speeds and Non-Breeding Areas Used by Northern Hemisphere Wintering Red Knots Calidris canutus of the Subspecies Rufa. Wader Study Bulletin, 119, 195-230.
[26]
Baker, A., Gonzalez, P., Morrison, R.I.G. and Harrington, B.A. (2013) Red Knot (Calidris canutus). The Birds of North America Online. https://doi.org/10.2173/bna.redkno.02
[27]
Lyons, J.E., Kendall, W.L., Royle, J.A., Converse, S.J., Andres, B.A. and Buchanan, J.B. (2015) Population Size and Stopover Duration Estimation Using Mark-Resight Data and Bayesian Analysis of a Superpopulation Model. Biometrics, 72, 262-271. https://doi.org/10.1111/biom.12393
[28]
Lathrop, R.G., Niles, L., Smith, P., Peck, M., Dey, A., Sacatelli, R., et al. (2018) Mapping and Modeling the Breeding Habitat of the Western Atlantic Red Knot (Calidris canutusrufa) at Local and Regional Scales. The Condor, 120, 650-665. https://doi.org/10.1650/condor-17-247.1
[29]
Kubelka, V., Šálek, M., Tomkovich, P., Végvári, Z., Freckleton, R.P. and Székely, T. (2019) Response to Comment on “Global Pattern of Nest Predation Is Disrupted by Climate Change in Shorebirds”. Science, 364, eaaw9893. https://doi.org/10.1126/science.aaw9893
[30]
Weiser, E.L., Brown, S.C., Lanctot, R.B., Gates, H.R., Abraham, K.F., Bentzen, R.L., et al. (2018) Effects of Environmental Conditions on Reproductive Effort and Nest Success of Arctic‐Breeding Shorebirds. Ibis, 160, 608-623. https://doi.org/10.1111/ibi.12571
[31]
McKellar, A.E., Ross, R.K., Morrison, R.I.G., Niles, L.J., Porter, R.R., Burger, J., et al. (2015) Shorebird Use of Western Hudson Bay near the Nelson River during Migration, with a Focus on the Red Knot. Wader Study, 122, 201-211. https://doi.org/10.18194/ws.00020
[32]
Tsipoura, N. and Burger, J. (1999) Shorebird Diet during Spring Migration Stopover on Delaware Bay. The Condor, 101, 635-644. https://doi.org/10.2307/1370193
[33]
Baker, A.J., González, P.M., Piersma, T., Niles, L.J., de Lima Serrano do Nascimento, I., Atkinson, P.W., et al. (2004) Rapid Population Decline in Red Knots: Fitness Consequences of Decreased Refuelling Rates and Late Arrival in Delaware Bay. Proceedings of the Royal Society of London. Series B: Biological Sciences, 271, 875-882. https://doi.org/10.1098/rspb.2003.2663
[34]
Niles, L.J., Sitters, H.P., Dey, A.D., Atkinson, P.W., Baker, A.J., Bennett, K.A., Carmona, R., Clark, K.E., Clark, N.A., Espoz, C., Gonzalez, P.M., Harrington, B.A., Hernandez, E.E., Kalasz, K.S., Lathrop, R.G., Matus, R.M., Minton, C.D.T., Morrison, R.I.G., Peck, M.K., Pitts, W., Robinson, R.A. and Serrano, I.L. (2008) Status of the Red knot, Calidris canutusrufa, in the Western Hemisphere. Studies in Avian Biology, 36, 1-185.
[35]
Niles, L.J., Bart, J., Sitters, H.P., Dey, A.D., Clark, K.E., Atkinson, P.W., et al. (2009) Effects of Horseshoe Crab Harvest in Delaware Bay on Red Knots: Are Harvest Restrictions Working? BioScience, 59, 153-164. https://doi.org/10.1525/bio.2009.59.2.8
[36]
Botton, M. L., Loveland, R.E. and Jacobsen, T.R. (1994) Site Selection by Migratory Shorebirds in Delaware Bay, and Its Relationship to Beach Characteristics and Abundance of Horseshoe Crab (Limulus polyphemus) Eggs. Auk, 111, 605-616.
[37]
McGowan, C.P., Hines, J.E., Nichols, J.D., Lyons, J.E., Smith, D.R., Kalasz, K.S., et al. (2011) Demographic Consequences of Migratory Stopover: Linking Red Knot Survival to Horseshoe Crab Spawning Abundance. Ecosphere, 2, art69. https://doi.org/10.1890/es11-00106.1
[38]
Atlantic States Marine Fisheries Commission (ASMFC) (1998) Interstate Fishery Management Plan for Horse-shoe Crab. ASMFC.
[39]
Atlantic States Marine Fisheries Commission (2009) A Framework for Adaptive Management of Horseshoe Crab Harvest in the Delaware Bay Constrained by Red Knot Conservation. 46 p.
[40]
Morrison, R.I.G. and Hobson, K.A. (2004) Use of Body Stores in Shorebirds after Arrival on High-Arctic Breeding Grounds. The Auk, 121, 333-344. https://doi.org/10.1093/auk/121.2.333
[41]
Guy Morrison, R.I., Davidson, N.C. and Wilson, J.R. (2007) Survival of the Fattest: Body Stores on Migration and Survival in Red Knots Calidris canutus Islandica. Journal of Avian Biology, 38, 479-487. https://doi.org/10.1111/j.2007.0908-8857.03934.x
[42]
Duijns, S., Niles, L.J., Dey, A., Aubry, Y., Friis, C., Koch, S., et al. (2017) Body Condition Explains Migratory Performance of a Long-Distance Migrant. Proceedings of the Royal Society B: Biological Sciences, 284, Article ID: 20171374. https://doi.org/10.1098/rspb.2017.1374
[43]
Brown, S., Hickey, C., Harrington, B. and Gill, R. (2001) The U.S. Shorebird Conservation Plan. 2nd Edition, Manomet Center for Conservation Sciences.
[44]
Clark, K.E., Niles, L.J. and Burger, J. (1993) Abundance and Distribution of Migrant Shorebirds in Delaware Bay. The Condor, 95, 694-705. https://doi.org/10.2307/1369612
[45]
Dey, A.D., Niles, L.J., Smith, J.A.M., Sitters, H.P. and Morrison, G. (2020) Update to the Status for the Red Knots (Calidris canutusrufa) in the Western Hemisphere. NJ Department of Environmental Protection, 17 p.
[46]
Lyons, J.E., Winn, B., Keyes, T. and Kalasz, K.S. (2017) Post‐Breeding Migration and Connectivity of Red Knots in the Western Atlantic. The Journal of Wildlife Management, 82, 383-396. https://doi.org/10.1002/jwmg.21389
[47]
Niles, L.J., Smith, J.A.M., Daly, D.F., Dillingham, T., Shadel, W., Dey, A.D., Danihel, M.S.M., Hafner, S. and Wheeler, D. (2013) Restoration of Horseshoe Crab and Migratory Shorebird Habitat on Five Delaware Bay Beaches Damaged by Superstorm Sandy. https://www.smithjam.com/wp-content/uploads/2014/03/RestorationReport_112213.pdf
[48]
Burger, J., Jeitner, C., Clark, K. and Niles, L.J. (2004) The Effect of Human Activities on Migrant Shorebirds: Successful Adaptive Management. Environmental Conservation, 31, 283-288. https://doi.org/10.1017/s0376892904001626
[49]
Burger, J., Carlucci, S.A., Jeitner, C.W. and Niles, L. (2007) Habitat Choice, Disturbance, and Management of Foraging Shorebirds and Gulls at a Migratory Stopover. Journal of Coastal Research, 23, 1159-1166. https://doi.org/10.2112/04-0393.1
[50]
Burger, J. and Niles, L.J. (2017) Habitat Use by Red Knots (Calidris canutusrufa): Experiments with Oyster Racks and Reefs on the Beach and Intertidal of Delaware Bay, New Jersey. Estuarine, Coastal and Shelf Science, 194, 109-117. https://doi.org/10.1016/j.ecss.2017.04.025
[51]
Ydenberg, R.C., Butler, R.W., Lank, D.B., Smith, B.D. and Ireland, J. (2004) Western Sandpipers Have Altered Migration Tactics as Peregrine Falcon Populations Have Recovered. Proceedings of the Royal Society of London. Series B: Biological Sciences, 271, 1263-1269. https://doi.org/10.1098/rspb.2004.2713
[52]
Watts, B.D. and Truitt, B.R. (2021) Influence of Introduced Peregrine Falcons on the Distribution of Red Knots within a Spring Staging Site. PLOS ONE, 16, e0244459. https://doi.org/10.1371/journal.pone.0244459
[53]
Hope, D.D., Lank, D.B., Smith, B.D. and Ydenberg, R.C. (2011) Migration of Two Calidrid Sandpiper Species on the Predator Landscape: How Stopover Time and Hence Migration Speed Vary with Geographical Proximity to Danger. Journal of Avian Biology, 42, 522-529. https://doi.org/10.1111/j.1600-048x.2011.05347.x
[54]
U.S. Fish and Wildlife Service (USFWS) (2014) Threatened Species Status for the Rufa Red Knot. Federal Register, 79, 73706-73748.
[55]
U.S. Fish and Wildlife Service (USFWS) (2014) Rufa Red Knot Background Information and Threat Assessment. Supplement to Endangered and Threatened Wildlife and Plants; Final Threatened Status for the Rufa Red Knot (Calidris canutusrufa). [Docket No. FWS-R5-ES-2013-0097; RIN AY17] U.S. Fish and Wildlife Service.
[56]
Dey, A., Niles, L.J., Smith, J.A., Sitters, H.P. and Morrison, G. (2017) Update to the Status of the Red Knot (Calidris canutusrufa) in the Western Hemisphere, September 2017. New Jersey, Department of Environmental Protection.
[57]
Hata, D. and Hallerman, E. (2018) Preliminary Results of the 2017 Horseshoe Crab Trawl Survey. Report to the ASMFC Horseshoe Crab and Delaware Bay Ecosystem Technical Committees. Dept. of Fish and Wildlife Conservation, Virginia Polytechnic Inst. and State University.
[58]
U.S. Fish and Wildlife Service (USFWS) (2016) Biological Opinion on the Effects of Existing and Expanded Structural Aquaculture of Native Bivalves in Delaware Bay, Middle and Lower Townships, Cape May County, New Jersey, on the Federally Listed Red Knot (Calidris canutusrufa). 175 p.
[59]
Smith, J., Niles, L., Hafner, S., Modjeski, A. and Dillingham, T. (2020) Beach Restoration Improves Habitat Quality for American Horseshoe Crabs and Shorebirds in the Delaware Bay, USA. Marine Ecology Progress Series, 645, 91-107. https://doi.org/10.3354/meps13371
[60]
Burger, J., Niles, L., Jeitner, C. and Gochfeld, M. (2018) Habitat Risk: Use of Intertidal Flats by Foraging Red Knots (Calidris canutusrufa), Ruddy Turnstones, (Arenaria interpres), Semipalmated Sandpipers (Calidris pusilla), and Sanderling (Calidris alba) on Delaware Bay Beaches. Environmental Research, 165, 237-246. https://doi.org/10.1016/j.envres.2018.04.028
[61]
National Oceanographic and Atmospheric Administration (NOAA) (2012) Communities: The U.S. Population Living in Coastal Watershed Counties. https://coast.noaa.gov/states/fast-facts/economics-and-demographics.html#:~:text=Almost%2040%25%20Live%20on%20the,land%20mass%20(excluding%20Alaska)
[62]
U.S. Census Bureau (2018) Population Density in New Jersey from 1960 to 2016. https://www.statista.com/statistics/206260/resident-population-in-new-jersey/
[63]
Senner, S.E. and Howe, M.A. (1984) Conservation of Nearctic Shorebirds. In: Burger, J. and Olla, B.L., Eds., Shorebirds, Springer, 379-421. https://doi.org/10.1007/978-1-4684-4691-3_9
[64]
Howe, M.A., Geissler, P.H. and Harrington, B.A. (1989) Population Trends of North American Shorebirds Based on the International Shorebird Survey. Biological Conservation, 49, 185-199. https://doi.org/10.1016/0006-3207(89)90035-9
[65]
Burger, J. (1986) The Effect of Human Activity on Shorebirds in Two Coastal Bays in Northeastern United States. Environmental Conservation, 13, 123-130. https://doi.org/10.1017/s0376892900036717
[66]
Burger, J. and Niles, L. (2012) Shorebirds and Stakeholders: Effects of Beach Closure and Human Activities on Shorebirds at a New Jersey Coastal Beach. Urban Ecosystems, 16, 657-673. https://doi.org/10.1007/s11252-012-0269-9
[67]
Burger, J. and Niles, L. (2013) Closure versus Voluntary Avoidance as a Method of Protecting Migratory Shorebirds on Beaches in New Jersey. Wader Study Group Bulletin, 120, 20-25.
[68]
Burger, J. and Niles, L. (2014) Effects on Five Species of Shorebirds of Experimental Closure of a Beach in New Jersey: Implications for Severe Storms and Sea-Level Rise. Journal of Toxicology and Environmental Health, Part A, 77, 1102-1113. https://doi.org/10.1080/15287394.2014.914004
[69]
Burger, J., Dey, A., Niles, L., Feigin, S. and Ng, K. (2022) Information Needed for Coastal Management: Perceptions of Research and Protection of Shorebirds on a Coastal Beach Are Influences by Visitor, Age, and Gender. UrbanEco-Systems, 26, 233-248.
