Conservation biology of the great crested newt in managed boreal forests in Finland

Abstract

This study focuses on the population and behavioral ecology of the endangered great crested newt in its natural forest habitat in Finland. I also explored the characteristics of the smooth newt and compared the two species. They are closely related but occur with different abundances in the same environments.Hatching success and survival of eggs were modelled using a combination of field and literature data. Eggs that were laid in the early season produced the best hatching results. This success rate dropped dramatically in combination with a decreasing water level. Terrestrial habitat characteristics, such as the amount of herb-rich forests, clear-cuts and broad-leaved trees, were related to the breeding success of the newts. Both newt species distinctly favored forests with high understory vegetation cover. Both the common and the rare species showed largely similar habitat use, however the rare species avoided clear-cut areas and was more abundant on sites where shelter was provided by the canopy and field-layer vegetation, especially when the distance to the pond increased.Four spatially and temporally different habitat and landscape scenarios were explored to model the extinction and colonization dynamics of the great crested newt. Intensified timber harvest and a shorter logging rotation were shown to decrease the connectivity between ponds.Overall, the results suggest that particular attention should be paid in conservation planning to the spatial arrangement of the habitat patches, especially if the intensity of the human impact is predicted to increase. The conservation effort must be targeted at securing the source ponds in the core area and the enhancement of connectivity between the habitat patches of the newts. As the hatching success of the great crested newt is strictly regulated by climatic factors, temperature and water level, a considerable future threat for the species might come with climate change.

Connectivity, land use, and fish presence influence smooth newt (Lissotriton vulgaris) occurrence and abundance in an urban landscape

“…Smooth newts inhabit both artificial and natural wetlands (Mulkeen et al, 2017;Mulkeen, 2018;Buono et al, 2019;Rannap et al, 2020), which allows breeding even in urban environments. They utilize a wide variety of waterbodies (Mulkeen et al, 2017) for reproduction, although they prefer still and shallow ponds (e.g., Kinne, 2004) and exhibit less strict aquatic habitat requirements when compared to other pond-reproducing newts (e.g., Skei et al, 2006;Gledhill et al, 2008;Vuorio, 2016). As smooth newts show extensive terrestrial stages in their life cycle and juveniles remain on land for several years until reaching reproductive readiness (e.g., Bell, 1977;Heiss et al, 2015), they require suitable terrestrial areas for hibernation, migration, and dispersal (Mulkeen et al, 2017).…”