Newsletter 10 | 28 May 2015

Dear readers,

We gladly present you with a fresh CWE newsletter, the first issue of the fourth phase of the CWE (2015-2020). Except a changing host institute, nothing changes: the CWE hosts two symposia and two newsletters per year. The past years CWE was located at Utrecht University and hosted by Jos Verhoeven and Rob Fraaije. We congratulate them with their excellent CWE symposia and newsletters. The last symposium they organised was the successful CWE symposium in Amsterdam themed "Back to the future, the ecological reshaping of Dutch waters".

The Netherlands Institute of Ecology (NIOO) will act as the host institute for the fourth phase of the CWE, with Liesbeth Bakker as chair and Bart Grutters as coordinator. The next CWE symposium about decomposition and peat formation is rapidly approaching and registration is open and for free.

We hope to welcome you at the next CWE symposium.

Bart Grutters (coordinator CWE)
Liesbeth Bakker (chair CWE)


Guest column: Prof. dr. Jos Verhoeven, "Subterranean Wetland Monsters"

Glowing insect larvae (Arachnocampa luminosa)
in Waitomo Cave, New Zealand.

The field trip during the 10th meeting of the Society of Wetland Scientists Europe Chapter in Slovenia took me to caves of Škocjanske jame just two weeks ago. The fascinating walk through the enormous karstic caves brought us in a series of gigantic halls eroded by a wild river, which at the time of our visit was flowing

below us relatively calmly. Our guide told us that water levels may rise very quickly in periods of high rainfall, making it dangerous to dwell there. Such caves with rivers, ponds and lakes have been included as ‘subterranean wetlands’ under de Ramsar Convention for wetland protection since the 1990s. They are inhabited by very peculiar life forms, called Troglobionts. One of the most well-known and impressive animals of this group in Slovenia is the Cave salamander or Olm (Proteus anguineus). As most Troglobiont animals, it has no eyes or body pigment and is adapted to relatively constant, cold conditions. It shows neoteny, which means it keeps many larval features, such as outside gills and small legs. It has lived for more than a million years in pitch-dark conditions. A few years ago in New Zealand, I sailed in a small boat on a little stream through a dark karstic cave only lit by many thousands of insect larvae producing weak spots of light. This Waitomo glowworm cave has a unique fairy-tale feel to it. The larvae of Arachnocampa luminosa, a mosquito-like gnat, are endemic to this region and are another example of cave-dwelling Troglobionts.

Proteus anguineus,
Cave salamander or Olm in Slovenia

While the Waitomo cave tour is an almost romantic experience, people have mostly seen large karstic caves with their spooky creatures with fear and awe. The caves were treacherous to get around in and if you went in them you encountered bats and olms, which have sometimes been described as small dragons. Such caves have also inspired writers, painters and movie directors. Tolkien pictured important parts of his Lord of the Rings epos in caves. I was immediately reminded of these movies and saw Gandalf flying around in cavities, saw Frodo fight with a real dragon in a cave pond. From an ecological point of view, it is interesting to think about the origin of all the energy driving the living creatures in these caves. With the absence of primary producers, all sources of energy must be forms of organic matter arriving in the caves by water flow or, in the case of bats or insects, by flying in. How much life could that support? I know of no study calculating energy flows based on trophic relations in caves. Most of the animal populations are very difficult to study and the population size of the Olm is totally unknown. Would there be sufficient resources coming in for one of these Tolkien monsters to live in such caves? A similar question has been discussed in one of our top journals, Limnology and Oceanography. Sheldon and Kerr (1972) used quantitative data on the various trophic levels in Loch Ness to calculate whether there would be a theoretical possibility that the lake would support large ‘monsters’. They assumed monsters to be top predators and concluded that the primary production and subsequent secondary and tertiary production would enable a population of 5-10 animals of 1500 kg adult weight. They reasoned that such a small population would run a strong risk of becoming extinct in a short time. No monsters in Loch Ness, is a safe conclusion. An even safer conclusion is that the tiny bits of organic matter flowing into caves do not support the large dragons Frodo was fighting in the ‘Rings’. The subterranean wetlands are still very much worth a trip though!

Sheldon, RW & Kerr, SR 1972. The population density of monsters in Loch Ness. Limnology and Oceanography 17: 796-798.

STOWA / Water mosaic

Maaien van waterplanten

  • Workshop on mowing aquatic plants: in many aquatic ecosystems submerged plants are highly successful on nutrient-rich sediments and the increasingly clear surface waters. Mowing is one of the options of controlling nuisance growth and this workshop aims to share best practises and experiences. More information is available on the STOWA website
  • Workhop dynamic coastal management: STOWA and RWS jointly organise a workshop on management, monitoring and development of coastal ecosystems. There is limited space, so register soon.
  • Final conference of the REFORM project: this conference allows researchers to discuss Novel Approaches to Assess and Rehabilitate Modified Rivers and is now open for registration. The conference is preceded by a Summer School for young researchers and students.

dr. Huub op den Camp

Other news

  • ERC Advanced Grant for microbiology of volcanoes: Dr. Huub op den Camp (RU) will study extremely acidophilic bacteria of Italian volcanoes. He hopes to unravel their role in carbon cycling and thinks that the novel research may lead to the discovery of new species. Read more on the RU website.
  • NWO Award for research on cyanobacterial control: Dr. Hans Matthijs and Dr. Petra Visser (UvA) received an award within the 'Licence to operate' NWO program for their research into controlling cyanobacteria using hydrogen peroxide. Read more on the UvA website
  • Call for symposium proposals 10th INTECOL IWC: The 10th edition of the most important global wetland meeting will be held in the nice town of Changshu, 100 km east of Shanghai. Symposium conveners may be sponsored with free registration and lodging if their proposal is approved by the scientific committee. These proposals are due June 30, 2015 and should be submitted by e-mail.

PhD graduations

  • Jasper Donker (UU), 20 May 2015, Hydrodynamic processes and the stability of intertidal mussel beds in the Dutch Wadden Sea". Personal page.
  • Marloes Hendriks (RU), 22 May 2015: "Effects of plant-soil feedback on root distribution, plant competition and community productivity". Personal page.
  • Brenda Walles (WUR), 1 June 2015: "The role of ecosystem engineers in the ecomorphological development of intertidal habitats". Personal page.
  • Lina Russ (RU), 9 July 2015: "Microbial nitrogen cycle interactions in laboratory-scale model systems". Personal page.

Recent key publications

  • Benincà et al. 2015. Species fluctuations sustained by a cyclic succession at the edge of chaos. PNAS.
  • Cusell et al. 2015. Impacts of short-term droughts and inundations in species-rich fens during summer and winter: Large-scale field manipulation experiments. Ecological Engineering.
  • Decaestecker et al. 2015. Parasite and nutrient enrichment effects on Daphnia interspecific competition. Ecology.
  • Declerck et al. 2015. Rapid adaptation of herbivore consumers to nutrient limitation: eco-evolutionary feedbacks to population demography and resource control. Ecology Letters.
  • van Diggelen et al. 2014. New Insights into Phosphorus Mobilisation from Sulphur-Rich Sediments: Time-Dependent Effects of Salinisation. PLOS ONE.
  • Elshout et al. 2015. Greenhouse gas payback times for crop-based biofuels. Nature Climate Change.
  • Fraaije et al. 2015. Early plant recruitment stages set the template for the development of vegetation patterns along a hydrological gradient. Functional Ecology.
  • Garssen et al. 2015. Riparian plant community responses to increased flooding: a meta‐analysis. Global Change Biology.
  • van Gerven et al. 2015. Competition for Light and Nutrients in Layered Communities of Aquatic Plants. The American Naturalist.
  • Grutters et al. 2015. Native and Non-Native Plants Provide Similar Refuge to Invertebrate Prey, but Less than Artificial Plants. PLOS ONE.
  • Harpenslager et al. 2015. To Float or Not to Float: How Interactions between Light and Dissolved Inorganic Carbon Species Determine the Buoyancy of Stratiotes aloides. PLOS ONE.
  • Hendriks et al. 2015. Spatial heterogeneity of plant–soil feedback affects root interactions and interspecific competition. New Phytologist.
  • van Nes et al. 2015. Causal feedbacks in climate change. Nature Climate Change.
  • Reichstein et al. 2015. Ontogenetic asymmetry modulates population biomass production and response to harvest. Nature Communications.
  • Scheffer et al. 2015. Creating a safe operating space for iconic ecosystems. Science.
  • van Teeseling et al. 2015. Anammox Planctomycetes have a peptidoglycan cell wall. Nature Communications.
  • Verspagen et al. 2014. Contrasting effects of rising CO2 on primary production and ecological stoichiometry at different nutrient levels. Ecology Letters.