Humboldt Bay • San Francisco Bay • San Diego Bay • Bahía de San Quintin • Bahía de Panamá • Iscuandé River Delta • ECUASAL Artifical Ponds
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Humboldt Bay
Wetland Description: Northern Humboldt Bay consists of marshes and mudflats with extensive eelgrass beds, wet pastures, and the estuary of the Mad River, which is separated from the ocean by extensive sand dunes. Arcata Marsh contains restored freshwater marsh habitat. Seven shellfish reserves are set aside for public clamming and oyster gathering. East bay marshlands were diked for railroad and highway construction. Humboldt Bay National Wildlife Refuge manages the southern Bay. A large marsh borders the southern bay; a vast system of tidal channels winds through wet pastures.
Shorebird Use: Depending on the season, 20,000 to 80,000 shorebirds reside in Humboldt Bay (Colwell 1994). The Western Hemisphere Shorebird Reserve Network (WHSRN) recognizes this large estuary as a site of International Importance for shorebirds. Tidal wetlands, especially the broad mudflats, support Dunlin, Long-billed Dowitchers, and Whimbrel (Colwell 1994).
Monitoring: Comprehensive surveys of the north and south portions of the bay have been conducted once a year, between 15 November and 15 December, since 2010 as part of the Pacific Flyway Shorebird Survey.
Survey Coordinator: Mark Colwell, Humboldt State University; Mark.Colwell@humboldt.edu
San Francisco Bay
Wetland Description: The San Francisco Bay is the largest estuary on the west coast of North America. San Francisco Bay contains a variety of habitats, including tidal mudflats, diked and undiked seasonal wetlands, managed and unmanaged salt evaporation ponds, and tidal marshes that support a diverse bird community. In addition, shorebirds use other features such as islands, levees, rip-rap shoreline, piers and other structures for roosting. The San Francisco Bay Area is also highly urbanized with over 6 million people and has undergone many changes over the last 200 years. In the late 1800s and early 1900s, over 80% of the wetlands were diked, channelized, and/or filled for agriculture, grazing, urban infrastructure, and other uses. During the shorebird surveys in the early 1990s, many areas in both the north and south regions of the estuary were still used as commercial salt evaporation ponds or were agriculture fields. In the 14 years between 1992 and 2006, over 11,000 acres of bayland were created or restored to tidal action by the California Department of Fish and Game, the U.S. Fish and Wildlife Service, and numerous other agencies. These restoration activities continue and the South Bay Salt Pond Restoration Project (www.southbayrestoration.org/) is the largest tidal restoration in the western United States. They have also changed the water management regimes of the salt ponds to maximize bird use. However, sea-level rise is projected to further change the distribution and abundance of shorebird habitat in the San Francisco Bay Estuary (see http://data.prbo.org/apps/sfbslr/).
Shorebird Use: More than 1 million shorebirds occur annually in the San Francisco Bay estuary representing 38 species (Stenzel et al. 2002). Shorebirds are most numerous in San Francisco Bay during spring migration, with up to 932,000 counted. However, fall and early winter are also important, with over 300,000 birds, and late winter (January-February) can have 225,000 (Stenzel et al. 2002). The overall abundance of wintering shorebirds has remained stable in San Francisco Bay over the last 15 years, despite significant changes in habitat; however there have been shifts in the distribution of some species (Wood et al. 2010).
Monitoring: Comprehensive surveys of the bay have been conducted by Point Blue Conservation and partners from 1990-1992 and 2006-2008 (see Stenzel et al. 2002 and Wood et al. 2010). In addition, localized surveys are being conducted regularly as part of studies by USGS and the San Francisco Bay Bird Observatory. Currently, Point Blue Conservation Science is working with partners to survey >120 sampling units annually during the PFSS survey window. These set of randomly selected sites represents ~50 – 60% of the shorebird population in the Bay. These surveys have been conducted in 2010 and 2011. See Reiter et al. (2011) for a detailed description of the San Francisco Bay Monitoring Design.
Survey Coordinator: Dave Shuford; Point Blue Conservation Science; dshuford@pointblue.org
San Diego Bay
Wetland Description: San Diego Bay consists of 11,000 acres of sub-tidal and intertidal habitat and 1,400 acres of salt ponds. Less than half of the mud flats that surrounded the bay in 1850 remain (766 acres). After the San Diego River was diverted, the large marsh at the river delta was filled and developed by the City of San Diego. The bay has been dredged to fill tidelands, to widen beaches along Silver Strand, and to create military and domestic ports. The dredged area is much deeper and narrower than 150 years ago. Only the south bay contains significant areas of marsh, mudflat, and salt ponds (Marcus and Kondolf 1989).
Shorebird Use: Holds up to 18,000 shorebirds in fall, 11,000 in winter, and 13,000 in spring (Terp 1998, Page et al. 1999). It is also recognized as a WHSRN site of Regional Importance. Tidal mudflats are the main shorebird feeding area; the salt ponds provide additional feeding and roosting habitat (Terp 1998). Sweetwater Marsh consists of salt and brackish marsh, salt pannes, mudflats, fill, and upland and supports breeding Snowy Plovers and many species of migrating and wintering shorebirds (B. Collins pers. comm.).
Monitoring: Comprehensive surveys of San Diego Bay were conducted in 2006 and 2009 by Tierra Data under contract with the US Navy, the Port of San Diego, and the US Fish and Wildlife Service. Counts were conducted on >300 sampling units throughout the Bay (a comprehensive survey). In 2011, Point Blue Conservation Science piloted a sampling design for San Diego Bay. Similar to San Francisco Bay (see Reiter et al. 2011), we selected a generalized random-tesselation stratified sample (GRTS) using the 2006 and 2009 species distribution data to guide the selection of sites. We selected ~30% of the sampling units (n = 100) weighting our selection of sampling units proportional to the natural log of shorebird abundance observed in previous surveys in those units. This strategy was shown to be successful in tracking population change with simulation analysis. Initial evaluation of this sampling strategy suggests that we can achieve population estimates for the Bay with coefficient of variation of <0.20. In fact, this strategy will still result in 50 – 60% of shorebirds being counted relative to 2006 and 2009 surveys. The GRTS sampling strategy also allows for additional sampling units to be added in the future if determined necessary.
Survey Coordinator: Matt Reiter; Point Blue Conservation Science; mreiter@pointblue.org
Bahia de San Quintin
Wetland Description: Bahía San Quintín is located on the Pacific coast of northwestern Baja California, about 300 km south of the Mexico-USA border, in the Municipality of Ensenada, Baja California, Mexico. It is the largest and the most important coastal wetland of the state of Baja California, the largest Mediterranean coastal wetlands in México and includes the most unaltered coastal salt marshes in the Californian region. It was recently designated as a Ramsar site. It covers more than 10,000 acres and is dominated by eelgrass (Zostera marina). Marine habitats also include salt marshes, channels, sand dunes, barrier beaches, and mudflats (40 % is exposed during low spring tides). The bay habitats are surrounded by coastal sage scrub mixed with desert scrub, and agricultural fields. Aquaculture of bivalve mollusks (especially Japanese oyster [Crassostrea gigas]) has been the main economic activity onsite since 1976. Other activities include: extraction of volcanic rock from the cinder cones; saltworks, sport, and artisanal fishing, and Black Brant hunting. These are allowed and regulated in the area. There is also intensive agriculture in the adjacent deltas and coastal plains.
Shorebird Use: A 1992 ground survey documented 31,925 migratory shorebirds for this wetland (Page et al. 1997). It is considered a key wetland for shorebirds in Mexico and it was designated as a WHSRN site of Regional Importance. Of the 31,925 migratory shorebirds 86% were in Bahía San Quintín, 4% in nearby salt ponds, and 11% at Laguna Figueroa. Marbled Godwits, Willets, and Long-billed Curlews made up 96% of the large species, dowitchers and Black-bellied Plovers 91% of medium species and Western Sandpipers and Dunlins 89% of small species. This site provides habitat for important breeding populations of several species or subspecies of birds that are threatened or endangered including Snowy Plover.
Monitoring: Two pilot surveys conducted by CICESE in December 2011 and January 2012. Point Blue Conservation Science and CICESE developing specific design for December 2012.
Survey Coordinator: Eduardo Palacios; Centro de Investigación Científica y de Educación Superior de Ensenada, B.C. (CICESE); epalacio@cicese.mx
Bahia de Panamá
(Photo credit: Audubon Society of Panama)
Wetland Description: The study area in the Bay of Panama wetlands includes mangrove forests, mudflats, estuaries and adjacent freshwater marshes, and shallow marine waters. These wetlands include approximately 297 km2 of mangroves, which constitutes about 21 % of the total coverage of 1395 km2 of mangroves of the Pacific coast, and 353 km2 of mudflats. The mudflats and mangroves are valued for their services to other parts of the ecosystem, especially infauna, invertebrates living in the sediment, which provide food for shorebirds, fish and shrimp. Mangroves are a unique immensely productive habitat that provides environmental services to rural and urban dwellers alike. The coastal area is optimal not only for shorebirds but is an important economic asset for the citizens of Panama.
Shorebird Use: In the wetlands of Panama Bay each fall millions of migratory shorebirds, including plovers, sandpipers and curlews, present a grand spectacle of world class natural history that can be easily seen from the shores of Panama’s capital city. Birds arrive attracted by the rich mudflats which extend for many kilometers from the edge of the city to the east and are full of clams, crustaceans and worms, very much appreciated by the hungry migrants. There are very few places along the entire Pacific coast of the hemisphere with the resources to sustain such huge amounts of shorebirds. The eastern Pacific coast of Panama has these resources in such abundance that many migrants remain during the winter and many juveniles remain in the country for their first summer. The Bay of Panama wetlands are home to approximately 31% of the world population of Western Sandpipers. Males and females of this species have different migration patterns, and 80 % of birds in this area are females (Watts 1998a ) . This means that about 50 % of the females of the western beach of the world depend on this site, most of them using the 30 km stretch just east of the city. A considerable proportion of the total world population of several other shorebird species also uses this habitat.
Importance to Seafood Industry: Shorebirds, along with large numbers of seabirds such as pelicans, gulls, terns and cormorants are only the most visible evidence of the rich marine resources that this area offers. Other beneficiaries of these wetlands include white shrimp and concha negra, a black-shelled mollusk. White shrimp, the main component of commercial shrimp fishing in Panama, feeds at the bottom of the Bay in shallow waters along the coast and their young feed in estuarine rivers of the area. The concha negra, collected in the mangroves by rural inhabitants along the coast, is highly prized as a food and sold in the markets of Panama and even exported to Europe.
Monitoring and Research: The first volume of The Birds of the Republic of Panama by Alexander Wetmore published in 1968, repeatedly mentions the immense flocks of western sandpipers ( Calidris mauri ) and other shorebirds in the nearby coastal city of Panama. Subsequently, The Canadian Wildlife Service in 1980 established a program to support conservation projects with Latin American countries. Following, in 1988, studies of population ecology of Western Sandpipers began in Panama. In 1997, Bryan D. Watts and colleagues conducted aerial surveys of birds using the different environments in the upper part of the Bay of Panama. Supported by The Center for Conservation Biology , and within the Legacy Resource Management Program of the Department of Defense in the U.S., he published the book “The migratory shorebirds in the upper Bay of Panama” (Watts, 1999a ). He estimated that between 1 and 2 million shorebirds pass through the intertidal zone during migration season. Watts also noted that 36 of the 49 species of water birds that breed in North America spend the winter in Latin America. For this reason since 2011 Audubon Society of Panama joined the Migratory Shorebird Project and has been participating in the winter monitoring of Western Sandpipers ( Calidris mauri ), to establish population trends and understand different aspects of ecological habitat use, diet and behavior, and in turn to determine the main aspects affecting the wetland distribution in Panama Bay.
Other Conservation Work in the Area: Among the initiatives in which we are working is the promotion of citizen science through the creation of a group of volunteers and the establishment of a scientific committee to identify research needs and advise on decisions to be taken by the authorities concerning the maintenance of the ecological character of the site. Additionally we are working in environmental education both in schools and surrounding communities with a focus on conservation of wetlands and migratory shorebirds.
Site Coordinator: Rosabel Miró, Executive Director of Panama Audubon Society, Skype name: rosabelmiro, Phone: (507) 6616-8954
Iscuandé River Delta, Colombia
Wetland Description: The site is partially included within the Sanquianga National Park and is the first Western Hemisphere Shorebird Reserve Network (WHSRN) site in Colombia, designated in 2009. Its regional importance as a WHSRN site is due to the presence of more than 1% of the hemispheric population of Wilson’s Plover, Charadrius wilsonia, and Spotted Sandpiper, Actitis macularia, and the presence of more than 20,000 shorebirds. Other species of numerical importance include Whimbrel, Numenius phaeopus, (> 200 individuals) and Dowitchers, Limnodromus sp., (> 1500 individuals). This important wetland site is located between the Colombian departments (similar to states or provinces) of Cauca and Nariño, bordered to the west by the Sanquianga National Park and to the northeast by the low Guapi River basin. It is located in the Sanquianga coastal system south of the Pacific Coast region. This site includes the area of mangroves and intertidal flats in the lower Esfuerzo Pescador Community Council, as well as a series of barrier islands off the coast. The Mouth of the river Iscuandé is dominated by mudflats with river sediment deposition, exposed to a tidal range of up to a 4m area. The most important shorebird areas of the Delta are the Cunita and Quinonez lowlands with an area of approximately 8,000 hectares, most of them tidal flat and shallow water.
Shorebird Use: The muddy planes of Mouth of the Rio Iscuande, are used by more than 30,000 shorebirds as shelter during high tides. About 28 species of shorebirds have been recorded in the area, the Western Sandpiper (Calidris mauri) being the most important in terms of numbers, with estimates of close to 25,000 individuals. The site is also important for the Semipalmated Plover (Charadrius semipalmatus) and Wilson’s Plover (Charadrius wilsonia). The latter presents migratory (probably C. w. Wilsonia) and nesting (C. w . Beldingi) stocks. Another interesting record was of 44 individuals of Common Oystercatcher (Haematopus palliatus), the highest number ever recorded for this site and for the Colombian Pacific. Finally there has been 27 individuals of Red Knot (Calidris canutus) recorded, also one of the highest counts of the species on the site.
Monitoring and Research: Asociación Calidris has been monitoring shorebirds at the site since 2000. Asociación Calidris scientists have been investigating trophic ecology of migratory and resident shorebirds, productivity, effects of pollution, and timing of migration. We sample two units, one in each of the barrier islands known as The Bass Cunita and Quiñónez. These islands are part of the belt barrier islands of the Pacific coast that are close to river mouths or associated with estuarine river mouths. The changing dynamics of the coast has caused these islands to increase in size and extension. These islands have been visited regularly since 2004 and are characterized by large areas of muddy intertidal flats, sandy beaches, grasslands and mangroves. In addition to studies of shorebirds in the area Asociacion Calidris has advanced studies of other waterfowl in the area.
Other Conservation Work in the Area: Asociación Calidris has been working on a conservation process to strengthen the capacity of sustainable community management of natural resources in the Iscuandé Delta. This process is framed in a Conservation Agreement signed by the local community and Asociación Calidris. Asociación Calidris’ purpose in this effort is to engage in the identification, construction and subsequent implementation of actions related to the environmental quality of the area, as well as the conservation of natural resources, goods and services that the area offers. The Conservation Agreement, signed in November 2011, has received support from the Conservation Fund for Development (Partnership Fund for Environmental Action and Children – Conservation International).
Site Coordinator: Carlos Ruiz, Asociación Calidris, cjruiz@calidris.org.co
Wetland Description: ECUASAL artificial pools were built by Ecuadorian Salt and Chemical Products Company (ECUASAL) in the late 1950s. This complex of artificial ponds encompasses 1500 ha (or 15 square miles) and is divided into two salt production plants. The first is called Mar Bravo (600 ha/6 sq.mi.) and is located 5km from the city of Salinas on Punta Carnero Way, in the Jose Luis Tamayo parish. The second is called Pacoa and is located between San Pablo and Monteverde, 40 km from Salinas within the parish of Colonche. The salt is produced in the production plants by the evaporation of sea water, so that the gaps have become an artificial ecosystem where communities of organisms interact in an abiotic extreme environment characterized by a gradient of salt. The ponds have been recognized for over 30 years by naturalists and nature lovers. There are currently 135 recorded bird species, 93 of which are aquatic and 23 of which are boreal shorebird migrants.
Shorebird Use: ECUASAL artificial ponds are key habitat for 23 species of Neotropical migrant shorebirds, 3 species of gull (Leucophaeus atricilla, L. pipixcan, Larus delawarensis), 6 species of tern, and 2 duck species (Anas discors y A. clypeata). This boreal migrant avifauna use the ponds as a resting site before continuing on to other places or they remain in the ponds for the winter. The ponds are home to at least 100,000 birds each year. During the fall migration period of 2008 53,000 Wilson’s Phalaropes were recorded, representing >3% of the biogeographic population of the species. The near-threatened Chilean Flamingo (Phoenicopterus chilensis), Peruvian Pelican (Pelecanus thagus), Elegant Tern (Thalasseus elegans), and in varying numbers, the critically endangered Peruvian Tern (Sternula lorata).
Monitoring and Research: Birds and Conservation/BirdLife Ecuador has been leading the neotropical waterbird census in Ecuador since 2004, the year in which the census at ECUASAL Wetlands of the larger area of Mar bravo and Pacoa began. Since late 2007, Bird and Conservation has been conducting monthly monitoring of waterbird populations in both wetlands supported by a group of trained local surveyors within the Important Bird Conservation Area Project. In the framework of this project, the continuity and maintenance of the waterbird monitoring program has been strengthened through research grants for college students to get involved. There have been several studies seeking to better understand the ecology of migratory and resident birds of the ECUASAL ponds.
Other Conservation Work in the Area: Under the Conserving Important Bird Areas, migratory waterbird priority Project at ECUASAL ponds, there are two action areas. One is working with key government officials to minimize the impact of nearby economic activities that effect the environment. The second is a robust education program that raises public awareness of the importance of the ecology of the ECUASAL ponds.
Site Coordinator: Ana Agreda, Aves y Conservación, aagreda@avesconservacion.org