Incidental Nest Predation and Lark Conservation in an Iberian Semiarid Shrubsteppe

Abstract

Steppe larks are rare species in Europe, and several reserves have been established in Spain to promote their conservation. Little is known, however, about the benefits these reserves provide for Iberian larks. At Las Amoladeras Bird Reserve predation of lark nests was high according to the Mayfield method: 68–99% of nests were preyed upon, primarily by red foxes (Vulpes vulpes) and feral dogs. A negative correlation between canid abundance and daily nest survival was detected, but there was no relationship between predator abundance and lark density. There was a positive correlation between canid track abundance and rabbit density. Evidence indicated that lark nest predation in the Iberian shrubsteppes was an example of incidental predation (Vickery et al. 1992), which nevertheless has caused serious conservation problems for the larks. Lark densities in some areas decreased 80% during the 3 years of our study. Incidental predation, which is determined by rabbit abundance, is a complicating factor for the conservation of these ground‐nesting birds and should be taken into account in the management of reserves for steppe birds.

Does afforestation increase bird nest predation risk in surrounding farmland?

“…Forest plantations may offer refuges for generalist predators, such as corvids and medium-sized carnivores, that otherwise would be absent or less abundant in open country, thereby increasing predation rates in surrounding habitats (Andrén, 1992;Pita et al, 2009). Also, afforestation may favour key prey such as lagomorphs (Hulbert et al, 1996), which in turn may increase predator activity and thus predation rates (Yanes and Suárez, 1996). Predation increases may also be expected from habitat fragmentation and the proliferation of edges associated with forest plantations, because predator abundance and activity is often higher in fragmented landscapes and close to habitat edges (Chalfoun et al, 2002).…”

“…Predation increases may also be expected from habitat fragmentation and the proliferation of edges associated with forest plantations, because predator abundance and activity is often higher in fragmented landscapes and close to habitat edges (Chalfoun et al, 2002). Losses of nest contents and adults to predators might eventually lead to population declines of vulnerable species (Yanes and Suárez, 1996;Fletcher et al, 2010). Non-lethal effects may also be relevant (Cresswell, 2008), as perceived predation risk may induce individuals to avoid breeding or foraging near wooded edges and in small patches (Ribic et al, 2009 and references therein), thereby causing reductions in the amount of usable habitat that are much larger than the area effectively occupied by forest plantations ).…”

“…Previous studies suggested that avoidance of forested habitats may, at least in part, be shaped by predation risk, particularly during the breeding season Morgado et al, 2010), because woody habitats may increase both predator abundances (Pita et al, 2009) and nest predation rates (Pescador and Peris, 2001). Furthermore, ground-nesting birds suffer high nest predation rates (Yanes and Suárez, 1995), and so increased densities of generalist predators may result in decreased body condition of breeding birds (Suárez et al, 2005a,b), and even population declines (Yanes and Suárez, 1996). Despite this, studies have yet to show a link between forest plantations, predator and prey abundances, and nest predation rates.…”

“…The effects of forest plantations on lagomorphs were also analysed, because previous studies showed a link between their abundance and bird nest predation rates in Mediterranean shrubsteppes (Yanes and Suárez, 1996). Specifically, the study tested the following predictions: (i) lagomorph and predator abundances increase with both cover by forest plantations and fragmentation of open habitats; (ii) bird nest predation rates are higher near forest plantation edges and are positively related to forest plantation cover and fragmentation of open habitats; (iii) bird nest predation rates increase with the abundance of lagomorphs and nest predators associated with forest plantations and fragmented landscapes.…”

Ecological effects of game management: does supplemental feeding affect herbivory pressure on native vegetation?

“…In the UK, predation is also the most important cause of nest failure and adult mortality in grouse (Thirgood et al 1998) or partridges (Potts 1980). In Spain, predation by generalist predators (mainly foxes and crows, but also other species) is also important in partridges (Yanes & Suarez 1996, Herranz 2001.…”