Assessing anthropogenic disturbances to develop buffer zones for shorebirds using a stopover site

Abstract

Anthropogenic disturbance can degrade the quality of stopover sites for migratory shorebirds. We investigated the potential effects of pedestrian traffic and shellfishing on foraging shorebirds at a key stopover site at Monomoy National Wildlife Refuge (Monomoy Refuge), Massachusetts, USA. We experimentally approached 11 species of shorebirds to quantify flight-initiation distances (FID) and found that species and age affected FID. Smaller Calidris sandpipers generally allowed pedestrians to approach within 25 m before flushing, whereas larger shorebirds (black-bellied plover [Pluvialis squatarola] and American oystercatcher [Haematopus palliatus]) had FID over 50 m. We also found that juveniles of all species had shorter FID than adults. Based on adult FID, we developed species-specific buffer distances for 11 species that ranged from 61 m for least sandpiper (Calidris minutilla) to 186 m for black-bellied plover. We also investigated the potential impacts of commercial and recreational shellfish harvesters, who rake forsoftshell clams (Mya arenaria) on mudflats where shorebirds actively foraged. Microhabitats with recent shellfishing activity had a positive influence on the density of 2 species (ruddy turnstone [Arenaria interpres], and American oystercatcher), whereas the presence of shellfishers did not appear to affect the density of other species of shorebird we monitored. We regularly detected black-bellied plovers and ruddy turnstones actively foraging in microhabitats where shellfishers had recently exposed sediment. Given the levels of shellfishing and pedestrian traffic at Monomoy Refuge, we found no evidence to suggest that current human activity has a strong negative impact on migratory shorebirds using Monomoy Refuge. However, if the amount of pedestrian traffic and shellfishing were to increase substantially, a buffer zone system might have to be implemented during peak migration periods to minimize impacts, with buffers >185 m from key foraging sites to reduce disturbance to the most sensitive species. Ó

Responses of Birds to Humans at a Coastal Barrier Beach: Napatree Point, Rhode Island

“…The median FID we documented when birds were disturbed by walkers or boats (~40 m) is similar to distances reported in previous studies (e.g., Blumstein 2003, Burger and Gochfeld 1991, Thomas et al 2003, but less than values reported for some larger species of shorebirds documented in other areas (e.g., Koch and Paton 2014), perhaps due to different methods of observation and analysis between studies. The disturbancedensity map we developed provides guidance for Napatree Point resource managers on possible regions from which pedestrians and boats should be excluded during migration periods and breeding season in order to reduce disturbance to birds (Ikuta andBlumstein 2003, Rodgers andSmith 1995).…”

“…Estimates of FID have significant ramifications for management of shorebird and waterbird breeding and stopover habitat , Koch and Paton 2014, Rodgers and Smith 1995, Weston et al 2012a). The median FID we documented when birds were disturbed by walkers or boats (~40 m) is similar to distances reported in previous studies (e.g., Blumstein 2003, Burger and Gochfeld 1991, Thomas et al 2003, but less than values reported for some larger species of shorebirds documented in other areas (e.g., Koch and Paton 2014), perhaps due to different methods of observation and analysis between studies.…”

“…There can also be a strong seasonal component to disturbances (Stillman and Goss-Custard 2002), with Burger (1986) documenting the highest rates of disturbance in May and August, when most migrating shorebirds are present and human use of beaches also tends to peak in the northeastern US. There is also interspecific variation in response to disturbance, with larger shorebirds (and birds in general) flushing at greater distances than smaller shorebirds in response to similar disturbances (Koch andPaton 2014, Weston et al 2012a).…”

Out of sight, out of mind? Testing the effects of overwinter habitat alterations on breeding territories of a migratory endangered species

“…3), which is coherent with reports of other raptors forced to use lower quality nest sites (Ferrer & Donazar, 1996;Mooney & Taylor, 1996;Kr€ uger, Simmons & Amar, 2015). Thus, it is necessary to develop buffer areas around habitual nest sites, in the hope that such planning measures will minimize disturbance impacts and promote population persistence in nesting areas (McCarthy et al, 1997;Don azar et al, 2002a;Koch & Paton, 2014).…”

Investigating the decline of ecosystem services in a production mangrove forest using Landsat and object-based image analysis

“…This could have eventually affected the migratory shorebird prey population, foraging rates and use of foraging and roosting sites (Koch and Paton, 2014). Prolonged or intense direct anthropogenic disturbance have been found to have caused the complete abandonment of stopover sites (Pfister et al, 1992).…”