Impact of human disturbance on the abundance of non‐breeding shorebirds in a subtropical wetland

Abstract

Shorebird populations have declined due to several threats throughout their annual cycle. Anthropogenic disturbance is one of the most ubiquitous threats to shorebird conservation in North America. Here, we studied the influence of human disturbance on shorebird community dynamics during migration and winter in Ensenada de La Paz, a subtropical coastal wetland in Mexico. We used negative binomial generalized linear mixed models to investigate the associations between spatial, biological, and anthropogenic variation and local shorebird abundance that accounted for shorebird body size (small, medium, and large) and foraging strategy (visual and tactile) of 22 shorebird species. After controlling for these different correlates of abundance, human disturbance (people, vehicles, and dogs) was negatively associated with shorebird abundance. During winter, all shorebird species were negatively related to human disturbance but positively associated with presence of raptors. However, small, tactile foraging birds exhibited a proportionally larger negative response to human disturbance than other shorebird types, indicative of guild-level sensitivities to human disturbance regimes. The positive association between shorebird abundance and disturbance from predators was unexpected. Shorebirds likely concentrate in large groups to reduce predation risk, resulting in higher densities of shorebirds occurring in areas with high predation risk. Understanding factors influencing the abundance and habitat use of shorebirds on their non-breeding grounds is paramount to support management and conservation policies for shorebirds and their habitats.

Population estimates of shorebirds on the Atlantic Coast of southern South America generated from large-scale, simultaneous, volunteer-led surveys

“…Surprisingly, with the exception of wetlands in Brazil, we did not find evidence that the proximity of a given site to urban areas had a significant effect on either shorebird presence or abundance (Tables 2 & 3). We had predicted that a close proximity to cities would have a negative effect on both presence and abundance, especially for shorebirds using beach habitats, as several studies have previously indicated that proximity to humans affects shorebirds during the breeding (Liley and Sutherland 2007, Hevia et al 2023), migratory (Pfister et al 1992, Murchison et al 2016), and nonbreeding seasons (LeDee et al 2008, Palacios et al 2022, Swift et al 2023). However, most cities are located close to estuaries (Small and Nicholls 2003) and, thus, the reliance of shorebirds on estuarine habitats may be stronger than the pressure to avoid urban areas.…”

An impact evaluation of conservation investments targeting long‐distance migratory species

“…For example, human disturbance or declining habitat quality could occur at sites even in the face of conservation outcomes (e.g., protected area designation). If a critical driver of site‐specific shorebird decline (e.g., human disturbance; Palacios et al., 2022) is not being mitigated with the activities being supported by investments, the lack of a difference in trends compared with sites with no conservation investment is not surprising.…”

Dogs density drives the reproductive effort of American Oystercatchers (Haematopus palliatus) in disturbed habitats of the Maule Region, central Chile

“…We logged each nest using a GPS. During each visit and each transect, we quantified the potential threats in the areas, including the number of people encountered (pedestrians, fishermen, and beach-and-sun tourists), vehicles (cars, tractors, and motorbikes), and dogs (free-ranging or with owners but off-the-leash), as done by Palacios et al (2022).…”

“…Shorebirds are a group of species that are highly dependent on coastal environments. In the case of shorebirds, human-related disturbances can affect individuals’ breeding, roosting, and foraging activities (Palacios et al 2022). Pedestrians, dogs, and motorized vehicle traffic on beaches also affect the energetic expenditure of shorebirds (Navedo et al 2019; Cortés et al 2021; Oliveros et al 2021; Gómez-Serrano 2021).…”