Effects of human presence on the long‐term trends of migrant and resident shorebirds: evidence of local population declines

Abstract

This study examines the responses to human presence of the most abundant shorebird species in an important coastal migration staging area (Los Lances Beach, southern Spain). Long‐term census data were used to assess the relationship between bird abundances and human densities and to determine population trends. In addition, changes in individual bird behaviour in relation to human presence were evaluated by direct observation of a shorebird resident species. Our results show that a rapid increase in the recreational use of the study area in summer has dramatically reduced the number of shorebirds and gulls which occur, limiting the capacity of the site as a post‐breeding stop‐over area. In addition, the presence of people at the beach significantly reduced the time that resident species spent consuming prey. Negative effects of human presence on bird abundance remain constant over the study period, showing no habituation to human disturbance in any of the studied species. Moreover, although intense human disturbance at Los Lances Beach occurs mainly in summer, the human presence observed is sufficient to have a negative impact on the long‐term trends of a resident shorebird species. The impacts of disturbance detected on shorebirds and gulls may be reversible through management actions that decrease human presence. We suggest a minimum distance of 80 m for any track or walkway from those areas where shorebirds are usually present, particularly during spring and summer, as well as an appropriate fencing in the most sensitive area.

Species richness patterns of waterbirds wintering in the gulf of Gabès in relation to habitat and anthropogenic features

“…In these large mudflats, waterbirds can position themselves far away from humans, which makes disturbance to be low. Other studies have also shown that the disturbing effect of human presence mainly occurred in narrow beaches (Lafferty, 2013;Martín et al, 2014). Second, most waterbirds, notably small species, seemed to be habituated to the presence of clam harvesters and did not perceive them as predators, especially as these clam harvesters generally moved slowly and were completely indifferent against birds.…”

“…Second, most waterbirds, notably small species, seemed to be habituated to the presence of clam harvesters and did not perceive them as predators, especially as these clam harvesters generally moved slowly and were completely indifferent against birds. Previous studies have shown that the disturbance of waterbirds was mainly due to people engaged in recreational activities and/or accompanied by domestics animals (Navedo and Herrera, 2012;Lafferty et al, 2013;Martín et al, 2014). Finally, it is possible that shorebirds benefited from clam harvesting activity, as turning over the sediment makes the invertebrates more available for shorebirds, especially for visual foragers.…”

Reconciling recreational use and conservation values in a coastal protected area

“…; Martín et al . ). Additionally, our study measured only the immediate redistribution of birds as a result of recreational use at small spatial scales (600‐m length of foreshore) and did not capture any chronic effects of disturbance over a larger spatial and temporal scale.…”

“…In some cases, temporary or permanent avoidance of suitable habitat can occur (Meager, Schlacher & Nielsen ; Lafferty, Rodriguez & Chapman ; Martín et al . ), ultimately reflected in lower local abundance, physiological condition or reproductive success (Gill ; Steven, Pickering & Castley ; Weston et al . ).…”

Managing human disturbance of wildlife in coastal areas

“…Anthropogenic causes are the form most commonly studied (Weston et al , p. 269) and are the focus of this discussion. Arising in a variety of forms, disturbance has been identified as limiting populations and species (Glover et al , p. 326; Koch and Paton , p. 58; Whitfield and Rae , p. 57; Martín et al , p. 73). Less evident than the direct species take, disturbance is a more cryptic and insidious form of damage.…”