Habitat type determines the effects of disturbance on the breeding productivity of the Dartford Warbler Sylvia undata

Abstract

Numerous studies have examined the causes and impacts of human disturbance on birds, but little is known about how these impacts vary among habitats. This is of applied importance both for predicting bird responses to changes in disturbance and in planning how to reduce disturbance impacts. The Dartford Warbler Sylvia undata, a key heathland breeding species, occupies territories in a range of heathland types. Three territory habitat groups were identified: heather‐dominated territories, heather territories with significant areas of European Gorse Ulex europaeus and territories containing Western Gorse U. gallii. Productivity was significantly affected by the timing of breeding in all habitats, but disturbance only appeared to have a significant impact on the productivity of birds in heather territories. Disturbance events in heather territories delayed breeding pairs for up to 6 weeks. This significantly decreased both the number of successful broods raised and the average number of chicks fledged per pair. Nests situated close to territory boundaries in heather territories, with high numbers of disturbance events, were more likely to fail outright. It was determined that an average of between 13 and 16 people passing through a heather territory each hour would delay breeding pairs sufficiently to prevent multiple broods.

Time-window of occurrence and vegetation cover preferences of Dartford and Sardinian Warblers after fire

“…Wildfires and changes in the fire regime have been cited among the major threats to this warbler (Tucker and Heath 1994), although several authors have shown that the species is abundant in burned areas of France, Spain, and Portugal (Pons and Prodon 1996;Herrando et al 2001;Moreira et al 2003). Although the bulk of the Dartford Warbler population and roughly 70% of its breeding range lie in a Mediterranean climate (BirdLife International 2011), most Dartford warbler ecological studies have been carried out in the small and peripheral English population (Bibby 1979;Catchpole and Phillips 1992;van den Berg et al 2001;Murison et al 2007), which faces a different environment, climate and threats than the Mediterranean populations. It is therefore essential to improve our knowledge of the species biology in its core range.…”

Reducing visitors’ group size increases the number of birds during educational activities: Implications for management of nature-based recreation

“…Organizing visitors in large groups may reduce the number of visits, which may be advisable if repeated impact has stronger effects on wildlife (Murison et al, 2007). However, this may have unwanted consequences if the impact of recreation on wildlife increases with the size of visitors' groups.…”

“…For example, outdoor activities that people often view as harmless (like hiking, biking or wildlife photography) have negative consequences on wildlife. Disturbed animals often interrupt temporarily vital activities such as feeding or breeding, which may reduce survival or breeding success (Ellenberg et al, 2006;Müllner et al, 2004;Murison et al, 2007;Yasué, 2005). If disturbance events are strong and repeated, many animals may end up abandoning the affected area, which may reduce the size of local populations and alter community assemblages (Fernández-Juricic, 2000;Mallord et al, 2007).…”

Efecto de la presencia humana sobre el comportamiento del Pato de Torrente Merganetta armata (Aves: Anatidae) en el Río Quindío (sector Boquía), Salento-Colombia

“…El caminar, ir en bicicleta o fotografiar la naturaleza puede generar consecuencias negativas para la fauna si se planifican mal dichas actividades. Frente a la presencia de humanos los animales interrumpen momentáneamente sus actividades vitales, tales como la alimentación o la reproducción, lo que puede disminuir la supervivencia o éxito reproductivo de las poblaciones silvestres (Müllner et al, 2004;Yasué, 2005;Ellenberg et al, 2006;Murison et al, 2007).…”