Immediate Response of Carabids to Small-Scale Wildfire Across a Healthy-Edge-Burnt Gradient in Young Managed Coniferous Forest in Central Europe

Abstract

Wildfire is a type of disturbance that plays a critical role in affecting forest ecosystems. Wildfires also have a significant effect on shaping arthropods communities. Carabids (family Carabidae) are often used as a bioindicator group of altered biocenoses. Methods: For carabid sampling, pitfall traps were used in three habitats, healthy-edge-burnt, fifteen days after the suppression of wildfire. Seven traps were evenly placed on each transect. In total, twenty-one traps were used for the study. Aim of the study: (i) evaluate the overall diversity of carabids, (ii) sex change and distribution within the studied habitats, (iii) dynamics of pyrophilous carabids. Results: In total, 1051 individuals within 42 species were recorded. The total number of species was higher in the edge and burnt habitats and differed from the healthy habitat. The abundance of carabids did not differ significantly across the three habitats. However, the healthy habitat exhibited both lower species numbers and abundance. Communities, species richness, and diversity indices were similar in the edge and burnt habitats, while the healthy habitat had lower species richness, diversity indices, and more homogenized communities. The overall sex ratio was nearly equal, with females comprising 519 individuals (49.4%) and males 532 individuals (50.6%), showing nonsignificant differences among study habitats. Among the nine most dominant species, a general trend of female dominance was observed. Many species showed different patterns in sex distribution in relation to the study habitats. Pyrophilous species accounted for the majority of individuals, comprising 55% of all carabids in the burnt habitat, predominantly represented by Pterostichus quadrifoveolatus. The rare species Sericoda quadripunctata was observed infrequently with only twenty-three individuals recorded. These two species are highly correlated, potentially indicating their near-habitat requirements. Males of pyrophilous species in general colonize the area in the earliest post-fire period. Conclusions: The immediate response of carabids to forest wildfire is significant, primarily influencing species richness and communities. While wildfire did not affect overall sex distribution, it shaped interspecies sex distribution across the study habitats.