Can a tropical water flea invade European lakes?

Mar 19, 2013
This picture shows Daphnia lumholtzi displaying a unique ability to form spectacular helmets and tail spines to defend themselves when exposed to fish (left individual), but not in the absence of fish (right individual). Credit: Christian Laforsch

Daphnia is a genus of small, planktonic crustaceans, commonly called 'water fleas' because of their jumpy swimming style and their size (between 0.2 and 5 mm). They live in various aquatic environments, ranging from acidic swamps to freshwater lakes, ponds, streams and rivers. Species of the genus Daphnia play a key role in freshwater food webs: they consume algae and are themselves an important food item for small fish.

Daphnia lumholtzi is a small subtropical and tropical representative, known as an invader in North America. It has never been found in Europe in the wild. were conducted by scientists from Ludwig-Maximilians-Universität München; ; and Technische Universität, München, to assess the possibilities of a potential invasion in Europe. The study was published in the open access journal NeoBiota.

This is a picture of one of the native European species, Daphnia Hyalina. Credit: Eva-Maria Harz

The experiments suggest that D. lumholtzi can invade European lakes and can cause substantial declines in the populations of native species, e.g. Daphnia hyalina and D. cucullata. It was also shown that absence of predatory fish may ease establishment in European lakes. Surprisingly, the invasive plankter proved to be a strong competitor even at temperatures as low as 15°C, despite its tropical origin.

This is a picture of European hybrid of D. hyalina and D. cucullata. Credit: Eva-Maria Harz

"We still do not know whether D. lumholtzi will invade European lakes, but our experiments did not identify any obstacles. In contrast to some studies suggesting that it might be filling an empty niche in North America, the results of our experiments indicate that it may suppress the population growth or even outcompete some native European Daphnia" says the lead author Meike J. Wittmann.

Explore further: Study reveals similar genetic, geographic patterns in monk parakeet

More information: Meike J. Wittmann, Wilfried Gabriel, Eva-Maria Harz, Christian Laforsch, Jonathan M. Jeschke, Can Daphnia lumholtzi invade European lakes? NeoBiota: 16: 39, doi: 10.3897/neobiota.16.3615

Related Stories

Loss of 'lake lawnmowers' leads to algae blooms

Sep 28, 2011

Unprecedented algae growth in some lakes could be linked to the decline of water calcium levels and the subsequent loss of an important algae-grazing organism that helps keep blooms at bay.

Changes in water chemistry leave lake critters defenseless

Sep 06, 2012

Imagine that the players on your favourite football team were smaller than their opponents, and had to play without helmets or pads. Left defenseless, they would become easy prey for other teams. Similarly, changes in Canadian ...

Recommended for you

Genetic variation is a necessity

24 minutes ago

The Earth is constantly changing. For new species to be able to adapt and cope with the changes, there must be sufficient genetic diversity, or genetic variation, in the population. But what type of diversity is required ...

Rare dune plants thrive on disturbance

16 hours ago

Beginning in the 1880s, coastal dunes in the United States were planted with European beachgrass (Ammophila arenaria) in an attempt to hold the sand in place and prevent it from migrating. The grass did th ...

Avoid 'crape murder' with limited pruning

Apr 27, 2015

Efforts to prevent people from committing "crape murder" are reducing the number of unsightly, knobby-knuckled branch ends but may leave people wondering how to correctly shape crape myrtles.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.