ABSTRACT
Metabolic rate has long been used in animal adaptation and performance studies, and individual oxygen consumption is used as proxy of metabolic rate. Stygofauna are organisms adapted to groundwater with presumably lower metabolic rates than their surface relatives. How stygofauna will cope with global temperature increase remains unpredictable. We studied the thermal acclimation and metabolic scaling with body mass of a stygobitic crustacean, Proasellus lusitanicus, in the climate change scenario. We measured oxygen consumption rates in a thermal ramp-up experiment over four assay temperatures and tested two hypotheses: (i) P. lusitanicus exhibits narrow thermal plasticity, inadequate for coping with a fast-increasing thermal regime; and (ii) oxygen consumption rates scale with the body mass by a factor close to 0.75, as commonly observed in other animals. Our results show that P. lusitanicus has low thermal plasticity in a fast-increasing thermal regime. Our data also suggest that oxygen consumption rates of this species do not follow mass-dependent scaling, potentially representing a new trait of metabolic optimization in groundwater habitats, which are often limited in food and oxygen. Species with limited dispersal capacities and rigid metabolic guilds face extinction risk due to climate change and omitting groundwater ecosystems from climate change agendas emphasizes the unprotected status of stygofauna.

Reference: Di Lorenzo T. & Reboleira A.S.P.S. (2022). Thermal acclimation and metabolic scaling of a groundwater asellid in the climate change scenario. Scientific Reports. https://www.nature.com/articles/s41598-022-20891-4

ABSTRACT
​Subarctic regions are particularly vulnerable to climate change, yet little is known about nutrient availability and biodiversity of their cave ecosystems. Such knowledge is crucial for predicting the vulnerability of these ecosystems to consequences of climate change. Thus, to improve our understanding of life in these habitats, we characterized environmental variables, as well as bacterial and invertebrate communities of six subarctic caves in Northern Norway. Only a minuscule diversity of surface-adapted invertebrates were found in these caves. However, the bacterial communities in caves were compositionally different, more diverse and more complex than the nutrient-richer surface soil. Cave soil microbiomes were less variable between caves than between surface communities in the same area, suggesting that the stable cave environments with tougher conditions drive the uniform microbial communities. We also observed only a small proportion of cave bacterial genera originating from the surface, indicating unique cave-adapted microbial communities. Increased diversity within caves may stem from higher niche specialization and levels of interdependencies for nutrient cycling among bacterial taxa in these oligotrophic environments. Taken together this suggest that environmental changes, e.g., faster melting of snow as a result of global warming that could alter nutrient influx, can have a detrimental impact on interactions and dependencies of these complex communities. This comparative exploration of cave and surface microbiomes also lays the foundation to further investigate the long-term environmental variables that shape the biodiversity of these vulnerable ecosystems.
​
Reference: Reboleira A.S.P.S., Bodawatta K.H., Ravn N., Lauritzen S.E., Øvrevik Skoglund R., Thomas-Poulsen M., Michelsen A., Jønsson K.A. (2022). Nutrient-limited subarctic caves harbour more diverse and complex bacterial communities than their surface soil. Environmental Microbiome, 17, 41. https://doi.org/10.1186/s40793-022-00435-z

ASBTRACT
Groundwater comprises the largest freshwater ecosystem on the planet. It has a distinct regime of extreme, yet stable environmental conditions that have favoured the development of similar morphological and functional traits in the resident invertebrate fauna (stygofauna).
The analysis of community traits is increasingly used as an alternative to taxonomy-based assessments of biodiversity, especially for monitoring ecosystem status and linking the functions of organisms to ecological processes, yet it has been rarely applied to stygofauna and groundwater ecosystems.
In this paper, we review the variation in functional traits among the invertebrate fauna of this important ecosystem. We focus on the stygofauna and processes of alluvium and fractured rock aquifers that are typified by small voids and fissures that constrain the habitats and environmental conditions.
As a first step, we compare trait variability between groundwater and surface water invertebrate communities and then examine the significance of the ranges of these traits to the vulnerability of the ecosystem to change.
Fifteen potentially useful functional traits are recognised, with ten of these having narrower ranges (i.e., exhibiting fewer states, or attributes, of a particular trait) in groundwater than they do in surface water.
Our synthesis suggests that the relative stability of groundwater environments has led to low trait variability. The low biomass and low reproductive rate of stygofauna suggest that recovery potential following disturbance is likely to be low.
For the purposes of both improved understanding and effective management, further work is needed to document additional functional traits and their states in groundwater fauna, enabling a better understanding of the relationship between response and effect traits in these ecosystems.
​
Reference: Hose et al. (2022). Invertebrate traits, diversity and the vulnerability of groundwater ecosystems. Functional Ecology. https://doi.org/10.1111/1365-2435.14125

References: Reboleira A.S.P.S. & Mateus O. (2022). Geologia, Grutas e Fauna Subterrânea do Planalto das Cesaredas. ​Captar: Ciência e Ambiente para Todos, 11. https://doi.org/10.34624/captar.v11i0.27451

Trichoniscoides sicoensis Reboleira & Taiti, 2015 from caves in the Sicó karst area.

Terrestrial isopods (Oniscidea) are the most diverse group of troglobionts in caves of continental Portugal. They occur in all karst regions of Portugal, play a major role in decomposition of organic matter in caves and may act as umbrella species for the conservation of all other cave-adapted invertebrates. We present the IUCN Red List profiles for the cave-adapted terrestrial isopods from continental Portugal, based on recent distribution data from caves.

Reference: Reboleira A.S.P.S., Eusébio R. & Taiti S. (2022). Species conservation profiles of cave-adapted terrestrial isopods from Portugal. Biodiversity Data Journal, 10: e78796. https://doi.org/10.3897/BDJ.10.e78796

Reference: Reboleira A.S.P.S., Moritz L., Santamaria S. & Enghoff H. (2021). Penetrative and non-penetrative interaction between Laboulbeniales fungi and their arthropod hosts. Scientific Reports. https://doi.org/10.1038/s41598-021-01729-x

The cave biodiversity of continental Portugal faces tremendous conservation challenges, mostly linked to their direct destruction and contamination infiltrating from the surface. Beetles are the most diverse insects and one of the most diverse arthropod groups in caves of Portugal. We present the IUCN Red List profiles for the cave-adapted beetles from continental Portugal, all endemic to their respective geological units and massifs. Ground beetles (Carabidae) are the most diverse family of cave-adapted beetles in continental Portugal, followed by rove beetles (Staphylinidae). Beetles in caves of Portugal are mostly terrestrial and only one species is known to have evolved to live in groundwater. Trechus is the most diverse genus with four species, followed by Domene with three species and by Speonemadus and Iberoporus, both with one cave-adapted species. The aim of this contribution is to assess all endemic cave-adapted species of beetles from continental Portugal and to support their specific protection, to promote adequate management of surface habitats and the establishment of priority areas for conservation. The main biodiversity erosion drivers that are impacting the conservation of the studied species are pollution infiltrating from the surface, urbaniation, modifications of the natural habitat for touristic purposes and mining, quarrying and energy production infrastructures. This document can be used in spatial planning and territory management in karst, based on the current scientific knowledge.

Reference: Reboleira A.S.P.S. & Eusébio R. (2021). Cave-adapted beetles from continental Portugal. Biodiversity Data Journal 9: e67426. https://doi.org/10.3897/BDJ.9.e67426

Reference: Eusébio R., Enghoff H., Solodovnikov A., Michelsen A., Barranco P., Salgado J.M., Sendra A. & Reboleira A.S.P.S. (2021). Temporal and spatial dynamics of arthropod groups in terrestrial subsurface habitats in central Portugal. Zoology. https://doi.org/10.1016/j.zool.2021.125931

On Wednesday, April 28, at 8:30pm (GMT+1), join us for the webinar "The Classical (Caves and) Karst", by Dr. Matej Blatnik, Researcher at the Karst Research Institute ZRC SAZU in Postojna (Slovenia).


The “Classical Karst” comprises the area between Ljubljana (Slovenia), Trieste (Italy) and Rijeka (Croatia), and it is the area with the oldest scientific exploration of karst. The first mentions to this geographical areas dates back to ancient times, whereas the scientific explanation of processes in karst areas began in the 17th century. The word “Karst” (originally kras), as well as the early descriptions of widespread karst phenomena, e.g. dolina, uvala, polje or ponor, originated from Slavic words and are result of early explorations in the Classical Karst. The first institute completely dedicated to karst exploration was established more than century ago in Postojna (Slovenia), with the main goal of developing the multidisciplinary study and protection of karst areas. Our travel across the Classic Karst will focus mostly on karstology, providing a geographical overview its caves and karst, historical perspective and current research trends, with amazing images from this iconic karst area.

“The Cave Show” is a series of (online) seminars about why are caves important, why it is important to study and protect caves, but also about our passion for caves, which drive much of our research activities. It is included in the celebrations of the International Year of Caves and Karst (http://iyck2021.org​).

More info: https://ce3c.ciencias.ulisboa.pt/outreach/press&events/ver.php?id=1308