Ponds are aquatic systems with small surface area (< 5 ha) and shallow depth (< 5 m). Even though these systems are numerous in almost any landscape worldwide, they have received less attention than larger lakes and rivers. Despite their small size, these systems have enormous global importance as they promote biodiversity, play key ecosystem functions, and connect the waterscape acting as stepping-stones in the dispersal of local species. However, their small size also makes them fragile and susceptible to impacts due to global change and other anthropogenic stressors (i.e. agriculture or urbanization) that can alter their water balance and eventually lead to their disappearance. For this session, we welcome both empirical (including a wide variety of ponds and pools) and experimental work (in the form of micro- or mesocosms), in addition to simulations and theory, focusing on population, community, or ecosystem scales in these understudied systems.
Lead Organizer: Zsofia Horvath, Institute of Aquatic Ecology, Centre for Ecological Research (hhzsofia@gmail.com)
Co-organizers:
Dunja Lukić, Research Department for Limnology, University of Innsbruck, Mondsee, Austria (dunjalkc@gmail.com)
David Cunillera-Montcusí, GRECO, Institute of Aquatic Ecology, University of Girona, Girona, Spain & FEHM-Lab (Freshwater Ecology, Hydrology and Management) Section of Ecology, Department of Evolutionary Biology, Ecology and Environmental Sciences University of Barcelona & Departamento de Ecología y Gestión Ambiental. Centro Universitario Regional Este (CURE). Universidad de la República (david.cunillera@dcm.cat)
Dani Boix, GRECO, Institute of Aquatic Ecology, University of Girona, Girona, Spain (dani.boix@udg.edu)
Presentations
08:30 AM
CONNECTIVITY IN A PONDSCAPE MATTERS FOR BIODIVERSITY EVEN ACROSS SMALL SPATIAL SCALES (5305)
Primary Presenter: Barbara Barta, Centre for Ecological Research/ ELTE Eötvös Loránd University (barta.barbara@ecolres.hu)
Understanding the processes that shape biodiversity and community composition is the central aim of metacommunity ecology. Pondscapes are useful model objects for studying landscape-level processes due to the high density of habitats which are easy to sample, and their overall high contribution to the regional species pool. Here, we studied the relative roles of space and environment in shaping species richness and community composition of a well-delineated network of 54 bomb crater ponds in Hungary. These man-made ponds are of the same age, similar size and shape, and there are strong underlying gradients in the landscape which makes this an ideal study system. We specifically tested the role of network centrality for species richness and eigenvector-based spatial arrangement for community composition for a range of organism groups (prokaryotes, microeukaryotes, zooplankton, macroinvertebrates and amphibians). We found that environmental filtering is the predominant driving force for community dynamics but a spatial signal was also detectable, especially for the passively dispersing groups. This highlights the importance of studying and protecting ponds as parts of a network rather than focusing on individual ponds.
08:45 AM
EFFECTS OF CONNECTIVITY LOSS ON MICROBIAL COMMUNITIES IN EXPERIMENTAL POND NETWORKS (5150)
Primary Presenter: Beáta Szabó, Centre for Ecological Research (schneiderbea@gmail.com)
Our knowledge on how habitat fragmentation affects biodiversity of aquatic microorganisms is primarily based on empirical studies. However, for a more realistic understanding of the underlying mechanisms, experiments that simultaneously investigate multiple taxonomical groups are needed. Our aim was to provide experimental proof for the negative effect of connectivity loss on microbial biodiversity by fragmentation in a habitat network. In an outdoor setup, we simulated six metacommunities, each consisting of five mesocosms (artificial ponds). For four weeks, weekly dispersal (water exchange) was carried out within each metacommunity, then it was terminated in three metacommunities to simulate connectivity loss, while it continued in the three control metacommunities for another 12 weeks. Applying 16S and 18S gene amplicon sequencing, we assessed the potential effects of fragmentation on biodiversity patterns of aquatic prokaryotes and unicellular microeukaryotes. By the end of the experiment, fragmentation resulted in a significantly lower alpha and gamma richness, and evenness of microeukaryotes, however, the strength of the treatment effect varied among the two trophic groups of microeukaryotes (autotrophs and heterotrophs). Our results revealed that under homogeneous environmental conditions, fragmentation remarkably decreased microeukaryotic diversity, while prokaryotes were not affected.
09:00 AM
ADDING BIOTIC INTERACTIONS TO METACOMMUNITY ANALYSIS (6694)
Primary Presenter: Stéphanie Gascón, University of Girona (stephanie.gascon@udg.edu)
Connectivity is not only a determinant for biodiversity at local and regional scale, but also for the functional structure of communities and its stability. Decreasing connectivity hinders dispersal among communities, changing biotic interaction networks, and eventually leading to the extinction of less competitive species. Thus, in isolated patches, species richness might decrease, while their contribution to beta diversity increase. In contrast, communities in central locations, more prone to mass effects, are expected to have more complex biotic interaction networks, because resources are not locally limited but subsidized by the ones of nearby. This would in turn increase community stability and would locally reduce the strength of biotic interactions. To test it, we have used data from a regional lake monitoring carried out from 1995 to 2015 (60 lakes in Sweden), and calculated the temporal species turnover, uniqueness, stability and biotic interactions of phytoplankton and invertebrates. We have then combined this information with the centrality metrics and the available environmental data from each monitored lake within a lake network obtained from a global lake database. Our preliminary results showed that the number of biotic interactions was positively related to species richness, turnover, and uniqueness, but negatively related to community stability. We also noticed that the number of interactions not only responded to isolation but also to environmental conditions, which is also true for biodiversity metrics at local and regional scale.
09:15 AM
What can we learn from anostracan past and present distribution? (5785)
Primary Presenter: Dunja Lukic, Donana Biological Station EBD-CSIC (dunjalkc@gmail.com)
Anostracans (Crustacea, Branchiopoda) are an ancient group specialised to temporary waters, which often represent extreme habitats due to their periodical drying or freezing. This crustacean group is characterised by relatively large body size, broad feeding spectrum and high consumption rates, and thus likely plays an important role in temporary water ecosystems. To bridge unfavourable periods within their habitats, anostracans form resting cysts resistant to a wide range of environmental conditions. In addition, they mostly disperse passively as resting cysts that can be picked up by wind and animals, such as birds or amphibians. In this study, we aim to reconstruct and collect information on genetic diversification and distribution history of several anostracan species. Moreover, we assess the factors determining the distribution range of anostracan species inhabiting several continents. We combine genetic data (using the mitochondrial COI gene region) and a diverse set of traits for each individual anostracan species to determine the factors influencing their past and present geographic distribution. As anostracan species differ considerably in their distribution range and habitat preferences, we hypothesise that their traits like the body length or the habitat type are playing a key role in their dispersal range and ability to establish at a new habitat. This work could also be of value for predicting the dynamics of temporary water communities as it is expected that the number and size of temporary water systems will change in the future due to climate change and human influence.
09:30 AM
ENVIRONMENTAL CHANGES ASSOCIATED WITH DRYING CLIMATE ARE EXPECTED TO AFFECT FUNCTIONAL GROUPS OF PRO- AND MICROEUKARYOTES DIFFERENTLY IN TEMPORARY SALINE WATERS (5151)
Primary Presenter: Zsuzsanna Márton, Institute of Aquatic Ecology, Centre for Ecological Research (mzsuzsi06@gmail.com)
Temporary ponds are among the most sensitive aquatic habitats to climate change. Their microbial communities have crucial roles in food webs and biogeochemical cycling, yet how their communities are assembled along environmental gradients is still understudied. This study aimed to reveal the environmental drivers of diversity (OTU-based richness, evenness, and phylogenetic diversity) and community composition from a network of saline temporary ponds, soda pans, in two consecutive spring seasons characterized by contrasting weather conditions. We used DNA-based molecular methods to investigate microbial community composition. We tested the effect of environmental variables on the diversity of prokaryotic (Bacteria, Cyanobacteria) and microeukaryotic functional groups (ciliates, heterotrophic flagellates and nanoflagellates, fungi, phytoplankton) within and across the years. Conductivity and the concentration of total suspended solids and phosphorus were the most important environmental variables affecting diversity patterns in all functional groups. Environmental conditions were harsher and they also had a stronger impact on community composition in the dry spring. Our results imply that these conditions, which are becoming more frequent with climate change, have a negative effect on microbial diversity in temporary saline ponds. This eventually might translate into community-level shifts across trophic groups with changing local conditions with implications for ecosystem functioning.
09:45 AM
BACTERIAL DIVERSITY AND ORGANIC CARBON USE IN SHALLOW LAKES AND PONDS ACROSS A WIDE SALINITY GRADIENT (7415)
Primary Presenter: Joan Casas-Ruiz, University of Girona (jpcasasruiz@gmail.com)
Saline inland waters are ubiquitous in arid and semi-arid regions and host a very unique ecology and biogeochemistry. Yet, how salinity shapes the structure and functioning of aquatic microbial communities in these systems remains elusive. Here, we investigated the diversity and functioning of bacterioplankton communities in shallow lakes and ponds across a wide range of naturally occurring salinity levels, from freshwater to hypersaline systems (specific conductivity ranging from 0.2 to >150 mS/cm). We characterized the diversity of the total (DNA-based) and active (RNA-based) community members and combined these genetic data with community-level metabolic profiles, extracellular enzymatic activities, and in situ organic carbon degradation essays. Bacterioplankton compositional differences across sites strongly aligned with the salinity gradient, indicating that salinity exerts a major environmental filtering on the community assemblages. Despite showing high bacterial abundance, communities in more saline systems had lower taxonomic and functional diversity, which translated into less diverse metabolic profiles (higher specialization) and lower carbon degradation rates. Altogether, our results provide new insights into the processes that shape bacterioplankton community assembly in saline lakes and may help anticipate how freshwater ecosystems willrespond to salinization in the mid-long term.
SS092A The Relevance of Small Systems: Pond Ecology in a Changing World
Description
Time: 8:30 AM
Date: 5/6/2023
Room: Sala Menorca B