AG Community & Evolutionary Ecology
The temporal, spatial and evolutionary dynamics of populations in coastal ecosystems are strongly influenced by interactions among species. Within the AG Community & Evolutionary Ecology we connect observational, experimental and molecular biological approaches to investigate the effects of these biotic interactions (e.g. predation and parasitism). We aim to identify the causes that lead to changes in population structure and species distributions and reveal general adaptive strategies of organisms confronted with changing environments. We focus on the effects of invasive species establishing new interactions and comparative ecosystem research. By using experimental approaches on various spatial scales much larger than the Wadden Sea we are analysing ecological patterns from the genetic to the community level.
Species interactions in biotic habitats
Sedimentary coasts such as the European Wadden Sea are dominated by endobenthic organisms living in the bottom. Only a few species form important habitats on the sediment surface which represent oases of biodiversity and species interactions. We investigate these kind of interactions in seagrass and mussel beds as well as in reefs of introduced oysters and algal forests. The results are used to assess the functional significance of these bioengineering species and biotic habitats.
Species introductions and effects
In many coastal ecosystems of the world an increasing number of introduced non-native species is observed which may strongly alter native habitats, species interactions and ecosytem functioning. We conduct an ongoing rapid assessment program on neobiota at German coasts and investigate the effects of exotic species on ecosystem level as well as their interactions with native organisms.
Effects of global change on the ecology of Arctic coasts
Currently, global warming especially causes strong effects on Arctic ecosystems. We study the consequences of increasing water temperatures on species interactions in Arctic benthic coastal communities. From these investigations we predict future scenarios for a warmer marine Arctic ecosystem and its species communites.
Species invasions as a tool to study rapid adaptation
Parasitism is a strong selective force that can lead to rapid evolutionary dynamics since hosts and parasites engage into an arms race between resistance/tolerance and infectivity/virulence. Invasive species offer an excellent opportunity to study these coevolutionary interactions because invasive hosts often leave their parasites behind when invading a new habitat. There they are often confronted with new parasites, which resets the evolutionary clock. We study adaptations of hosts and parasites on the phenotypic and the geneotypic level using invasive Pacific oysters as a host for opportunistic Vibrio bacteria, and invasive copepod parasites (Mytillicola intestinalis und Mytillicola orientalis) that infect blue mussels as a new host in the Wadden Sea. The rapid evolutionary repsonses occuring over <10 generations demonstrate the strength of parasite selection as well as the usefulness to use invasive species to investigate these questions.
- Wendling, C.C., Wegner, K.M. (2015). Adaptation to enemy shifts: rapid resistance evolution to local Vibrio spp. in invasive Pacific oysters. Proc Roy Soc B:Biol Sci 282 (1804) 20142244
- Wendling, C.C., Batista, F.M., Wegner, K.M. (2014). Persistence, seasonal dynamics and pathogenic potential of Vibrio communities from Pacific oyster hemolymph. PLoS ONE 9, e94256
- Wendling, C.C., Wegner, K.M. (2013). Relative contribution of reproductive investment, thermal stress and Vibrio infection to summer mortality phenomena in Pacific oysters. Aquaculture 412-413, 88-96.
Genetic and non-genetic mechanisms of adaptation
Phenotypic plasticity can buffer the detrimental effects of stressful environments, because the same genotype can produce different phenotypes depending on environmental conditions. This enables a fast repsonse to changing selction regimes. If a correlation between environment of the parents and of the offspring exists, it can be a selective advantage to transfer information about phenotypically plastic traits to the offspring. We investigate the epigenetic mechanisms of transgenerational plasticity (TGP) in the context of ocean warming and performance in a marine population of the threespine stickleback (Gasterosteus aculeatus), and could show that the thermal environment of the mother has a strong influence on the fitness of the offspring in a matching environment. Mechanistically the plastic adaptation is linked to higher efficiency of the mitochondrial energy metabolism that are directly transferred from mother to offspring via the eggs. Effects seen at the physiological and phenotypic level are underlain by changes in gene expression (transcriptomes) inherited from mothers and grandmothers, indicating an epigenetic basis to TGP.
- Shama, L.N.S., Strobel, A., Mark, F.C., Wegner, K.M., 2014. Transgenerational plasticity in marine sticklebacks: maternal effects mediate impacts of a warming ocean. Functional Ecology 28, 1482-1493.
- Shama, L.N., Wegner, K.M., 2014. Grandparental effects in marine sticklebacks: transgenerational plasticity across multiple generations. J Evol Biol 27, 2297-2307.
- Shama, L.N.S, Mark, F.C., Strobel, A., Lokmer, A., John, U., Wegner, K.M., 2016. Transgenerational effects persist down the maternal line in marine sticklebacks: gene expression matches physiology in a warming ocean. Evolutionary Applications 9, 1096-1111.
- Donelson, J.M., Salinas, S., Munday, P.L., Shama, L.N.S., 2018. Transgenerational plasticity and climate change experiments: where do we go from here? Global Change Biology 24, 13-34.
Microbial symbiont: the host as a habitat
Higher organisms are not only part of ecosystems - they also represent an ecosystem for a diverse assemblage of microbes. These microbiota are important for many physiological processes of the host (e.g. development, digestion, but also defense against parasites and disease). With the help of moder sequecning technology we investigate the role of mircrobiota in various organs of oysters, mussels and fish under changing envrionmental conditions and infection by parasites. We could show that a stable, diverse microbial community in the hemolypmh can protect marine bivalves from infections, but that these communities are also vulnerable to environmental pertubations linking the envrionment to the host via its microbiota.
- Lokmer A, Wegner KM (2015) "Hemolymph microbiome of Pacific oysters in response to temperature, temperature stress and infection", ISME Journal 9:670-682
- Wegner KM, Volkenborn N, Peter H, Eiler A (2015) "Disturbance induced decoupling between host genetics and composition of the associated microbiome" BMC Microbiology 13:25
- Wegner KM, Shama LNS, Kellnreitner F, Pockberger M (2012) Diversity of immune genes and associated gill microbes of European plaice Pleuronectes platessa, Estuarine, Coastal and Shelf Science 108:87-96
We are currently looking for motivated bachelor and master´s students for spring / summer 2020. If interested, contact us via email.
e.g.: AG Shama is looking for a Master student to conduct a mesocosm experiment investigating climate variability - ecosystem function.