Ferrante et al. (2014) European Journal of Entomology

Ferrante M, Lo Cacciato A, Lövei GL (2014): Quantifying predation pressure along an urbanisation gradient in Denmark by using artificial caterpillars. European Journal of Entomology 111: 649-654. doi: 10.14411/eje.2014.082

Abstract

Urbanisation results in a marked modification of habitats and influences several ecological processes, some of which give rise to beneficial ecological services. Natural pest control, the effect of predators on prey is one of such services. We quantified changes in the incidence of predation with increasing levels of urbanisation using artificial caterpillars made of green plasticine. Potential predators can be identified by the “attack marks” they leave on these artificial caterpillars. We conducted this study from May to October 2010 around the city of Sorø (Zealand, Denmark), in forests along an urbanisation gradient (rural-suburban-urban). Artificial caterpillars were placed on the ground in order to obtain an estimate of the incidence of predation at ground level. Half (50%) of the 1398 caterpillars were “attacked” and 28.8% of the bites were those of chewing insects. We attributed the majority of these to carabids, the most common group of ground-active arthropods. Chewing insects exerted the greatest predation pressure in the original forest (52.1%), with lower values recorded in the suburban (10.1%) and urban (16.4%) forest fragments. Ants were responsible for only 4.7% of the attacks in forest, 11.3% in suburban and 16.4% in urban forest fragments. Mammals exerted the highest predation pressure in suburban
habitats (22.2% vs. 4.9% in forest, and 8.1% in urban forest fragments).

Keywords

Carabidae, Formicidae, fragmentation, natural enemies, ecosystem services, predation, urbanisation, sentinel prey

Purger et al. (2012) Polish Journal of Ecology

Purger, J. J., Mužinić, J., Purger, D. (2012): Survival chances of ground nests in a meadow habitat: a case study in Vrana Lake Nature Park (Mediterranean region, Croatia). Polish Journal of Ecology 60 (1): 247-252.

Abstract

The number of ground-nesting bird species in meadows, one of the most vulnerable habitats in the ornithological reserve of Vrana Lake Nature Park has decreased in recent decades. Nest survival rates were investigated in meadows and reed beds using nest predation experiments in late March and in May 2005. Predators damaged 18% of the 50 artificial nests placed in the pasture meadow habitat in March and 22% in May. Daily survival rate of nests were found to be similar in March (97%) and May (96%). In May, 64% of 25 nests located in the reed bed were discovered by the predators, with the daily survival rate of nests (90%) being significantly lower than that of nests in the nearby meadow. The results suggest that the reasons for the decreasing number of nesting bird species may be – instead of the pronounced presence and activity of predators in the area – the shrinkage of meadow area, the lack of buffer zone, the proximity of agricultural lands, and disturbance caused by intensive grazing.

Keywords

artificial nest, predation, survival rate, threats, Vransko jezero

Kurucz et al. (2012) North-Western Journal of Zoology

K. Kurucz, L. Bertalan & J.J. Purger (2012): Survival of blackbird (Turdus merula) clutches in an urban environment: experiment with real and artificial nests. North-Western Journal of Zoology 8 (2): 362-36.


Abstract
During 2009 and 2010 in the city of Pécs (Hungary) 59 active blackbird (Turdus merula) as well as 59 artificial nests were observed. Among the real nests 26 (44%) were successful, 14 (24%) were predated, and 19 (32%) were abandoned by the parent birds. Among the artificial nests 34 (57%) remained intact, but 25 (42%) were predated. Regarding the failure of real nests, if we consider both predation and abandonment during the incubation period, the daily survival rates of real nests (n = 59) DSR (0.952) were significantly lower than the DSR of artificial nests (0.977). If we consider only predation rates (n = 41), the daily survival rates of the two nest types did not differ significantly (real nests 0.976, artificial nest 0.978). Consequently, the daily survival rates of artificial bush nests used by us reflect precisely the predation pressure on real blackbird nests.


Keywords
predation, artificial bush nests, quail eggs, plasticine eggs, Hungary