Soil mesofauna are essential members of soil ecosystems, providing key services and serving as bioindicators. Yet, sampling them effectively remains a challenge. Classical extraction methods provide true density estimates but underrepresent mobile, surface-active taxa, while pitfall traps capture mobile species disproportionately and yield only activity-density data. Below-ground pitfall traps (BPTs) were developed to address these shortcomings by sampling both epigeic and euedaphic mesofauna with minimal disturbance. Despite their promise, BPT designs face conceptual and mechanical limitations, including biases towards motile species, susceptibility to environmental variation, and difficulties in standardisation. This paper critically reviews BPTs as an emerging tool in soil ecology. We argue that their appropriateness is highly context- and objective-dependent. BPTs are valuable for monitoring temporal dynamics, long-term or remote studies, and activity-based community assessments, but are less suitable when accurate density estimates or fine-scale treatment effects are required. Recognising these strengths and limitations, we conclude that BPTs should be regarded as complementary to, rather than replacements for, traditional extraction methods. Progress in trap design, alongside continued refinement of established techniques, will be necessary to improve comparability and reliability in soil biodiversity research.
Deforestation of primary forests is a significant cause of biodiversity loss. Globally, secondary forests and native plantations are more commonly used for forest recovery. However, the benefits of these habitat types, such as their support for biodiversity and ecosystem functions, are often debated. Finding strategies that enhance biodiversity and ecosystem health is crucial for making effective management decisions. We used leaf litter invertebrates as an indicator of forest recovery success, recognizing its vital role in ecosystem processes. We examined how recovery strategies (secondary forest versus Andean alder plantation) and the dominant plant species in each influence invertebrate responses (richness, abundance, functional diversity, community composition) during leaf litter decomposition. Our results reveal that recovery strategy and plant identity affect the invertebrate community, particularly in abundance and community composition. Decomposition timing also impacts species richness, abundance, and functional diversity, with the middle stage showing the highest levels. This study indicates that Andean alder plantations, which are native forestry plantations, perform similarly to secondary forests in terms of invertebrate richness and functional diversity during litter decomposition. Additionally, plant identity should be considered in reforestation plans, as it influences variations in invertebrate responses among different restoration strategies throughout the decomposition process.
Reliable assessment of compost maturity in industrial windrow systems remains challenging because physicochemical indicators do not fully capture biological succession. Although nematodes are established indicators of compost maturity, their integration with routine physicochemical measurements into predictive frameworks remains limited. This study therefore evaluated whether nematode assemblages could be used to develop and evaluate a predictive framework for compost maturity under industrial windrow conditions. Six replicate industrial windrows were monitored over seven months using high-frequency biweekly sampling (16 intervals). Nematode communities were characterised morphologically and analysed together with temperature, moisture, pH, and electrical conductivity measurements. Nematode assemblages showed clear successional shifts during composting, with enrichment-associated bacterivores such as Diploscapter, Panagrolaimidae, and Rhabditis dominating early phases and fungal-associated taxa including Aphelenchoides and Hexatylina increasing during maturation. These shifts reflect succession in bacterial- and fungal-based decomposition pathways involved in organic matter breakdown and stabilisation during compost maturation. The Nematode-based Index of Compost Maturity (NICM) increased significantly from interval 8 onwards, indicating the transition to maturity, although a temporary decline occurred during a period of reduced moisture. Multivariate analyses showed that nematode community composition was significantly structured by moisture, pH, and sampling interval. A Random Forest model predicted the Nematode Index of Compost Maturity with high accuracy (R² = 0.9), with a limited subset of taxa contributing most strongly to model performance. These results show that variation in the NICM could be predicted from key nematode taxa and routine physicochemical measurements. The proposed framework therefore provides a foundation for biologically informed prediction of compost maturity in industrial windrows, although further validation is required before operational application.
Centipedes and spiders are dominant terrestrial predators, with several halophilic species restricted to the intertidal zone. The drivers influencing both the abundance and the distribution of these halophilic species are poorly studied, especially along the Mediterranean coast. To understand this, we sampled 92 transects of beaches in the Port-Cros National Park (France). Level of human disturbance had the strongest impact on the distribution of all focal species. The dominant sediment type was less influential, except for the centipede Tuoba poseidonis. In sandy and gravel beaches, the microhabitats provided by pebbles impacted chilopod presence significantly. The quantity of stranded Posidonia had no significant influence on the presence of halophilic species; however, the spider Chaerea maritimus and the centipedes Henia bicarinata and Pachymerium ferrugineum, were more abundant when there were at least small “banquettes”. Halophilic geophilomorphs, along with C. maritimus, seemed to have a very low dispersal ability. Given that five of the six target species are relatively easy to collect (in comparison to other halophilic arthropods) and that three can be identified in the field using non-lethal methods, these species can act as strong bioindicators, as well as good umbrella-species for halophilic soil fauna. Using these as indicators, 87% of the beaches within the Port-Cros National Park are in an unfavourable state of conservation. We recommend that Chaerea maritimus, Geophilus fucorum, Henia bicarinata and Tuoba poseidonis should be added to regional and national protection lists and taken into account when impact studies are conducted along the Mediterranean coast.
