E. Martin Österling

Genomics and the challenging translation into conservation practice

The global loss of biodiversity continues at an alarming rate. Genomic approaches have been suggested as a promising tool for conservation practice as scaling up to genome-wide data can improve traditional conservation genetic inferences and provide qualitatively novel insights. However, the generation of genomic data and subsequent analyses and interpretations remain challenging and largely confined to academic research in ecology and evolution. This generates a gap between basic research and applicable solutions for conservation managers faced with multifaceted problems. Before the real-world conservation potential of genomic research can be realized, we suggest that current infrastructures need to be modified, methods must mature, analytical pipelines need to be developed, and successful case studies must be disseminated to practitioners.

Reply to Garner et al.

Genomics in Conservation : Case Studies and Bridging the Gap between Data and Application Reply

LetterReply to Garner et al.

Genomics in Conservation : Case Studies and Bridging the Gap between Data and Application Reply

Timing, growth and proportion of spawners of the threatened unionoid mussel Margaritifera margaritifera: influence of water temperature, turbidity and mussel density

Anthropogenic disturbances often cause decline and extinction of threatened species. The present study investigated how gravid freshwater mussels, Margaritifera margaritifera, were affected by turbidity and water temperature, and by mussel density. At an early date of mussel spawning, there were lower proportions of gravid mussels in streams with evidence of mussel recruitment than in streams without mussel recruitment. At a late spawning date, this pattern was reversed. Higher water temperature in streams without recruitment was probably responsible for this difference. The combination of high water temperature and turbidity may be one reason for reduced growth of gravid mussels in streams without recruitment. There was a positive relationship between adult mussel density and the proportions of gravid mussels. Early gravidity may lead to early release of larvae, early infestation on the host fish and an earlier start of the benthic phase, which may reduce survival rates. Clear-cutting of forests and global warming are factors that are likely to cause increased turbidity/sedimentation and water temperatures in streams. One restoration measure that reduces sediment input and water temperatures is maintaining or restoring riparian zones, but these are long-term measures that require many years before they have an effect in streams.

Evaluating temperature- and host-dependent reproduction in the parasitic freshwater mussel Unio crassus

Adaptation to temperature regimes and host presence may enhance fitness in parasites. In an experimental study, we evaluated the timing of glochidia release by Unio crassus subjected to three spring water temperature regimes in the presence and absence of the host fish Cottus gobio. The timing of glochidia release was delayed at (i) constantly low temperatures (<10°C), in contrast to earlier and pronounced releases at (ii) natural temperature increases that level off at intermediate temperatures (10–15°C), and (iii) higher-than-normal temperatures (10–20°C). Mussels from treatment (i) that had not released glochidia during the experiment did so soon after being moved to the temperature in (ii), indicating a temperature threshold for glochidia release. Neither host fish presence nor the combined effect of temperature and host fish presence significantly affected the timing of glochidia release. The treatment with natural spring water temperatures indicated possible fitness benefits for U. crassus through combined effects of high intensities of glochidia releases and high survival of released glochidia. The furthered understanding of climate change effects on mussel and host phenology in seasonal environments, potentially inducing temporal mismatches of glochidia release to host availability, is key to mussel conservation.

Encystment of parasitic freshwater pearl mussel (Margaritifera margaritifera) larvae coincides with increased metabolic rate and haematocrit in juvenile brown trout (Salmo trutta)

Gill parasites on fish are likely to negatively influence their host by inhibiting respiration, oxygen transport capacity and overall fitness. The glochidia larvae of the endangered freshwater pearl mussel (FPM, Margaritifera margaritifera (Linnaeus, 1758)) are obligate parasites on the gills of juvenile salmonid fish. We investigated the effects of FPM glochidia encystment on the metabolism and haematology of brown trout (Salmo trutta Linnaeus, 1758). Specifically, we measured whole-animal oxygen uptake rates at rest and following an exhaustive exercise protocol using intermittent flow-through respirometry, as well as haematocrit, in infested and uninfested trout. Glochidia encystment significantly affected whole-animal metabolic rate, as infested trout exhibited higher standard and maximum metabolic rates. Furthermore, glochidia-infested trout also had elevated levels of haematocrit. The combination of an increased metabolism and haematocrit in infested fish indicates that glochidia encystment has a physiological effect on the trout, perhaps as a compensatory response to the potential respiratory stress caused by the glochidia. When relating glochidia load to metabolism and haematocrit, fish with low numbers of encysted glochidia were the ones with particularly elevated metabolism and haematocrit. Standard metabolic rate decreased with substantial glochidia loads towards levels similar to those of uninfested fish. This suggests that initial effects visible at low levels of encystment may be countered by additional physiological effects at high loads, e.g. potential changes in energy utilization, and also that high numbers of glochidia may restrict oxygen uptake by the gills.