Consequences of Climate Change-Induced Habitat Conversions on Red Wood Ants in a Central European Mountain: A Case Study

Abstract

The consequences of anthropogenic climate change are one of the major concerns of conservation biology. A cascade of negative effects is expected to affect various ecosystems, one of which is Central European coniferous forests and their unique biota. These coniferous forests are the primary habitat of many forest specialist species such as red wood ants. Climate change-induced rising of temperature allows trees to skip winter hibernation, making them more vulnerable to storms that cause wind felling, and in turn, promotes bark beetle infestations that results in unscheduled clear-cuttings. Red wood ants can also be exposed to such habitat changes. We investigated the effects of bark beetle-induced clear-cutting and the absence of coniferous trees on colonies of Formica polyctena, including a mixed-coniferous forest as a reference. Our aim was to investigate how these habitat features affect the nest characteristics and nesting habits of F. polyctena. Our results indicate that, in the absence of conifers, F. polyctena tend to use different alternatives for nest material, colony structure, and food sources. However, the vitality of F. polyctena colonies significantly decreased (smaller nest mound volumes). Our study highlights the ecological flexibility of this forest specialist and its potential to survive under extreme conditions.

Wood ants as biological control of the forest pest beetles Ips spp.

“…The presence of red wood ants is strongly linked to habitat features, which is the main reason why the changes in their habitat had strongly affected their populations resulting in their current threatened status 23 . Besides factors like the availability of proper food sources, nesting places, and the material for mound construction 37 , also the temperature and isolation properties are important determinants of the presence of the red wood ant nests both at local and at larger scales [48][49][50] . Moreover, the combination of the large-and small-scale factors, like the reduction of the insolation on a local scale due to the shading by the tree canopy has been demonstrated to exert an important effect on the F. polyctena nests size and distribution 48 .…”

“…where h is the height of the nest, and r 1 and r 2 are the two perpendicular nest radii. We used this equation because the above-ground nest volume is closely related to the red wood ant colony size [48][49][50] .…”

Wood Ants: Important Components of the Forest "Immunity System"

“…The presence of red wood ants is strongly linked to habitat features which is the main reason why the changes in their habitat had strongly affected their populations, resulting in their current threatened status (33). Besides factors like the availability of proper food sources, nesting places, and the material for the construction of their mounds (85), also the temperature and isolation are important determinants of the presence of the red wood ant nests both at local and at larger scales (35,36,71). Moreover, the combination of the large and small scale factors, like the reduction of the insolation on a local scale due to the shading by the tree canopy has been demonstrated to exert an important effect on the F. polyctena nests size and distribution (35).…”

“…where h is the height of the nest, and r1 and r2 are the two perpendicular nest radii. We used this equation because the above-ground nest volume is closely related to the red wood ant colony size (35,36,71).…”

“…In this concern, different management techniques have been developed in order to facilitate an early detection to minimalize the damage caused by different pests (1,11). However, these techniques are designed to overcome the current situation, many times not considering the long term effects and the well-being of many other forest-dwelling species, like birds (as woodpeckers; 24, 39, 40), parasitoids (31,38) or other arthropods (as the clerid beetle Thanasimus dubius; 69) including wood ants (36,85).…”