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Microbial diversity of caves is largely understudied and its possible applications are still unknown. Autochthonous fungi, in particular, may have the potential to biomineralize metals and may be used as promising agents for bioremediation of polluted sites; thus, unearthing the fungal diversity in hypogean ecosystems is nowadays of utmost importance. To start addressing this knowledge gap, the cultivable mycobiota of two neighbouring caves-one natural and one exploited for touristic purposes-were characterised and compared by studying fungi isolated from sediments collected at increasing distances from the entrance. Overall, 250 fungal isolates ascribable to 69 taxa (mainly Ascomycota) were found, a high percentage of which was reported in caves for the first time. The sediments of the touristic cave displayed a richer and more diversified community in comparison with the natural one, possibly due to visitors carrying propagules or organic material. Considering that these environments are still poorly explored, chances to detect new fungal lineages are not negligible., (© 2024. The Author(s).)

Changes in the species richness of (meta-)communities emerge from changes in the relative species abundance distribution (SAD), the total density of individuals, and the amount of spatial aggregation of individuals from the same species. Yet, how human disturbance affects these underlying diversity components at different spatial scales and how this interacts with important species traits, like dispersal capacity, remain poorly understood. Using data of carabid beetle communities along a highly replicated urbanization gradient, we reveal that species richness in urban sites was reduced due to a decline in individual density as well as changes in the SAD at both small and large spatial scales. Changes in these components of species richness were linked to differential responses of groups of species that differ in dispersal capacity. The individual density effect on species richness was due to a drastic 90% reduction of low-dispersal individuals in more urban sites. Conversely, the decrease in species richness due to changes in the SAD at large (i.e., loss of species from the regional pool) and small (i.e., decreased evenness) spatial scales were driven by species with intermediate and high dispersal ability, respectively. These patterns coincide with the expected responses of these dispersal-type assemblages toward human disturbance, namely, (i) loss of low-dispersal species by local extinction processes, (ii) loss of higher-dispersal species from the regional species pool due to decreased habitat diversity, and (iii) dominance of a few highly dispersive species resulting in a decreased evenness. Our results demonstrate that dispersal capacity plays an essential role in determining scale-dependent changes in species richness patterns. Incorporating this information improves our mechanistic insight into how environmental change affects species diversity at different spatial scales, allowing us to better forecast how human disturbance will drive local and regional changes in biodiversity patterns., (© 2022 The Ecological Society of America.)

Subterranean ecosystems are among the most widespread environments on Earth, yet we still have poor knowledge of their biodiversity. To raise awareness of subterranean ecosystems, the essential services they provide, and their unique conservation challenges, 2021 and 2022 were designated International Years of Caves and Karst. As these ecosystems have traditionally been overlooked in global conservation agendas and multilateral agreements, a quantitative assessment of solution-based approaches to safeguard subterranean biota and associated habitats is timely. This assessment allows researchers and practitioners to understand the progress made and research needs in subterranean ecology and management. We conducted a systematic review of peer-reviewed and grey literature focused on subterranean ecosystems globally (terrestrial, freshwater, and saltwater systems), to quantify the available evidence-base for the effectiveness of conservation interventions. We selected 708 publications from the years 1964 to 2021 that discussed, recommended, or implemented 1,954 conservation interventions in subterranean ecosystems. We noted a steep increase in the number of studies from the 2000s while, surprisingly, the proportion of studies quantifying the impact of conservation interventions has steadily and significantly decreased in recent years. The effectiveness of 31% of conservation interventions has been tested statistically. We further highlight that 64% of the reported research occurred in the Palearctic and Nearctic biogeographic regions. Assessments of the effectiveness of conservation interventions were heavily biased towards indirect measures (monitoring and risk assessment), a limited sample of organisms (mostly arthropods and bats), and more accessible systems (terrestrial caves). Our results indicate that most conservation science in the field of subterranean biology does not apply a rigorous quantitative approach, resulting in sparse evidence for the effectiveness of interventions. This raises the important question of how to make conservation efforts more feasible to implement, cost-effective, and long-lasting. Although there is no single remedy, we propose a suite of potential solutions to focus our efforts better towards increasing statistical testing and stress the importance of standardising study reporting to facilitate meta-analytical exercises. We also provide a database summarising the available literature, which will help to build quantitative knowledge about interventions likely to yield the greatest impacts depending upon the subterranean species and habitats of interest. We view this as a starting point to shift away from the widespread tendency of recommending conservation interventions based on anecdotal and expert-based information rather than scientific evidence, without quantitatively testing their effectiveness., (© 2022 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.)

Body size is intrinsically linked to metabolic rate and life-history traits, and is a crucial determinant of food webs and community dynamics 1,2 . The increased temperatures associated with the urban-heat-island effect result in increased metabolic costs and are expected to drive shifts to smaller body sizes 3 . Urban environments are, however, also characterized by substantial habitat fragmentation 4 , which favours mobile species. Here, using a replicated, spatially nested sampling design across ten animal taxonomic groups, we show that urban communities generally consist of smaller species. In addition, although we show urban warming for three habitat types and associated reduced community-weighted mean body sizes for four taxa, three taxa display a shift to larger species along the urbanization gradients. Our results show that the general trend towards smaller-sized species is overruled by filtering for larger species when there is positive covariation between size and dispersal, a process that can mitigate the low connectivity of ecological resources in urban settings 5 . We thus demonstrate that the urban-heat-island effect and urban habitat fragmentation are associated with contrasting community-level shifts in body size that critically depend on the association between body size and dispersal. Because body size determines the structure and dynamics of ecological networks 1 , such shifts may affect urban ecosystem function.

The increasing conversion of agricultural and natural areas to human-dominated urban landscapes is predicted to lead to a major decline in biodiversity worldwide. Two conditions that typically differ between urban environments and the surrounding landscape are increased temperature, and high patch isolation and habitat turnover rates. However, the extent and spatial scale at which these altered conditions shape biotic communities through selection and/or filtering on species traits are currently poorly understood. We sampled carabid beetles at 81 sites in Belgium using a hierarchically nested sampling design wherein three local-scale (200 × 200 m) urbanization levels were repeatedly sampled across three landscape-scale (3 × 3 km) urbanization levels. First, we showed that communities sampled in the most urbanized locations and landscapes displayed a distinct species composition at both local and landscape scale. Second, we related community means of species-specific thermal preferences and dispersal capacity (based on European distribution and wing morphology, respectively) to the urbanization gradients. We showed that urban communities consisted on average of species with a preference for higher temperatures and with better dispersal capacities compared to rural communities. These shifts were caused by an increased number of species tolerating higher temperatures, a decreased richness of species with low thermal preference, and an almost complete depletion of species with very low-dispersal capacity in the most urbanized localities. Effects of urbanization were most clearly detected at the local scale, although more subtle effects could also be found at the scale of entire landscapes. Our results demonstrate that urbanization may fundamentally and consistently alter species composition by exerting a strong filtering effect on species dispersal characteristics and favouring replacement by warm-dwelling species., (© 2017 John Wiley & Sons Ltd.)

Land use change-mostly habitat loss and fragmentation-has been recognized as one of the major drivers of biodiversity loss worldwide. According to the habitat amount hypothesis, these phenomena are mostly driven by the habitat area effect. As a result, species richness is a function of both the extent of suitable habitats and their availability in the surrounding landscape, irrespective of the dimension and isolation of patches of suitable habitat. In this context, we tested how the extent of natural areas, selected as proxies of suitable habitats for biodiversity, influences species richness in highly anthropogenic landscapes. We defined five circular sampling areas of 5 km radius, including both natural reserves and anthropogenic land uses, centred in five major industrial sites in France, Italy and Germany. We monitored different biodiversity indicators for both terrestrial and aquatic ecosystems, including breeding birds, diurnal butterflies, grassland vegetation, odonata, amphibians, aquatic plants and benthic diatoms. We studied the response of the different indicators to the extent of natural land uses in the sampling area (local effect) and in the surrounding landscape (landscape effect), identified as a peripheral ring encircling the sampling area. Results showed a positive response of five out of seven biodiversity indicators, with aquatic plants and odonata responding positively to the local effect, while birds, vegetation and diatoms showed a positive response to the landscape effect. Diatoms also showed a significant combined response to both effects. We conclude that surrounding landscapes act as important biodiversity sources, increasing the local biodiversity in highly anthropogenic contexts.

The term Milieu Souterrain Superficiel (MSS) has been used since the early 1980s in subterranean biology to categorize an array of different hypogean habitats. In general terms, a MSS habitat represents the underground network of empty air-filled voids and cracks developing within multiple layers of rock fragments. Its origins can be diverse and is generally covered by topsoil. The MSS habitat is often connected both with the deep hypogean domain-caves and deep rock cracks-and the superficial soil horizon. A MSS is usually characterized by peculiar microclimatic conditions, and it can harbor specialized hypogean, endogean, and surface-dwelling species. In light of the many interpretations given by different authors, we reviewed 235 papers regarding the MSS in order to provide a state-of-the-art description of these habitats and facilitate their study. We have briefly described the different types of MSS mentioned in the scientific literature (alluvial, bedrock, colluvial, volcanic, and other types) and synthesized the advances in the study of the physical and ecological factors affecting this habitat-i.e., microclimate, energy flows, animal communities, and trophic interactions. We finally described and reviewed the available sampling methods used to investigate MSS fauna.

The composition of the volatile fraction of two important forage legumes from Italian sub-alpine N.E. pastureland, namely Trifolium pratense L. subsp. pratense (red clover) and T. repens subsp. repens (white clover) were investigated. The volatile oil was obtained from the fresh aerial parts by steam distillation and analyzed by GC/FID and GC/MS. The oil yield was 0.018 and 0.021% (weight/fresh weight basis) for T. pratense and T. repens, respectively. Several classes of compounds were found in both the oils, including alcohols, aldehydes, ketones, terpenes, esters, hydrocarbons, phenolics and acids. Qualitative and quantitative differences were found.