Freshwater jellyfish in France.

This summer we experienced a very long period of drought and two scorching heat waves which are probably the reason for an unusual and little known phenomenon to occur in the Vienne departement along with other parts of west and southwest France! These were exactly the right conditions when the water warms sufficiently for the emergence of a tiny freshwater jellyfish, craspedacusta sowerbii.  

They are normally only seen when they take the form of a small bell-shaped jellyfish known as a hydromedusa and float near the surface of the water but this requires a water temperature of at least 25°C and forms only one part of their interesting lifecycle.

As a jellyfish they are 20–25 mm in diameter, somewhat flatter than a hemisphere, and very delicate. They have a whorl of up to 400 tentacles tightly packed around the bell margin. Hanging down from the center of the inside of the bell is a large stomach structure called a manubrium, with a mouth-opening and four frilly lips. Food is taken in and waste  expelled through the mouth opening.

Click photo to enlarge

Craspedacusta sowerbyi more often exist as microscopic podocysts (dormant "resting bodies"), frustules (larvae produced asexually by budding), planulae (larvae produced sexually by the hydromedusae), or as sessile polyps, which attach to stable surfaces and can form colonies consisting of two to four individuals and measuring 5 to 8 mm.

This species, originally from China (Yangtze River Basin), probably originally arrived in Europe with aquatic plants imported for botanical gardens. In the ponds of Kew Gardens, near London, it was discovered in 1880 by the naturalist William Sowerby. Since then, it has conquered every continent thanks to the trade in aquarium plants.

In France they can be found in slow moving rivers, lakes and ponds, maybe even your garden pond if they have been transported there with pond plants or stuck to birds’ feet.  Should you come across them you need not worry, they present no danger to humans or other mammals.

Chris

A few French frogs and newts at Chaunay.

When the LGV from Tours to Bordeaux was being constructed there were a large number of environmental impacts that had to be considered as a matter of law these days and I will go into them at a later date. Here I only want to touch upon one site, Le bocage humide de Chaunay a wetland site site in the south west of the Vienne departement of some importance.

All in all at this site some 120 hectares were purchased by Réseau ferré de France, (RFF), which is the company that owns and maintains the French national railway network.  The land is comprised of moderately managed small copses and hedged fields that have been cut for hay. It’s something of an exception among the wetlands of the department. With no connection to any river an alluvial aquifer feeds directly into the pools and ditches creating large area of seasonal surface water. With a handful of man made ponds left in existence another 7 have or are being created on the 45 hectares that have been contracted to CREN, (Conservatoire d’Espaces Naturels de Poitou-Charente), for 25 years. CREN in turn are establishing a management plan with farmers that use the land regarding types and timing of any hay cutting that will take into account the various species present.

The site is particularly rich and includes some of the rarer and endangered amphibian species that have been lost in huge numbers due to the vast destruction of ponds and habitat throughout the region over the last 50 years or so.  I bet like me you must get sick of hearing this, everywhere we look it’s the same old story and sadly not getting any better.

Anyway, on a positive note this particular site is relatively safe although there are some issues that will be difficult to resolve as we shall see.

When observing or compiling records for amphibian species at any given site it’s necessary to do this at night essentially combining two different means. The first is to listen and identify any of the frog or toad species present. To do this, having approached the pond, we then turn off all lights and wait 5 minutes as little by little they settle down and get back into their calling. As with most other creatures each species has its own unique call and for some it may be the only way we can determine their presence.  

Next it’s light and time for a careful search in the shallow margins. The water will be slightly warmer here and it’s where mating takes place for most amphibians. For many species there is no need to actually capture them, simple observation is enough, indeed strictly speaking it’s illegal to capture them without being authorised and absolutely illegal to deliberately harm or move one.

Of particular interest is the Triton de Blasius a hybrid newt that results from the mating between a male Great Crested Newt, (Triturus cristatus), and a female Marbled Newt, (Triturus marmoratus), which obviously requires the prescence of both species. Biologically the males are sterile and females only partly fertile. There is no typical Blasius but the essential features are the back with the markings of a Marbled Newt and the belly of a Great Crested Newt.

Click on photos to enlarge.

Photos below of Triton de Blasius.

Photo below of Male Common tree frog 

Photo below of an Agile frog

Photo below of Female Palmate Newt

Photo below of Female Great Crested Newt

Other species are also present at the same site - Marbled Newt, Common toad and Parsley Frog. 

There remains as I mentioned one not so small issue and that is the presence of Procambarus clarkii, Red Swamp Crayfish  an introduced species from the USA. This species can reach 85-90mm total length and are aggressive in behaviour presenting a threat to the native amphibian species that are there. Due to  the protected nature of this site only authorised trapping can take place but as it is a species that will move through ditches and indeed overland in wet conditions total eradication is unlikely. 

 Photo below  Procambarus clarkii, Red Swamp Crayfish

Chris

Ponds in Poitou-Charentes France

Ponds in Poitou Charentes from an article in Living Magazine.

Living in this part of France with water on demand at the turn of a tap, it’s easy to forget that as little as 20 to 25 years ago there were many people in small hamlets that only had the well to supply their needs. Pumped domestic water for many is a relatively recent phenomenon in rural France. The further we go back, the more people depended on other means to provide and store water for themselves and their livestock which included different types of ponds, troughs and containers depending on the purposes they would be required for. In turn, these often provided an important habitat for a range of species, amphibians, reptiles, insects and plants. Sadly, many have been lost for one reason or another or have been altered to satisfy our desire for ornamentation.

Read the full Article here. 

La Réserve Naturelle du Pinail

Human activity has always changed the environment and in this article in 2014 I took a quick look at an extraordinary area that since 1980 has been the first and only State Nature Reserve in the Vienne departement of France, La Réserve Naturelle du Pinail which is located in the commune of Vouneuil-sur-Vienne, (86210). The Reserve is 30 km north-east from Poitiers and 15 km south from Chatellerault where it sits high on the plains between the river valleys of the Vienne and the Clain, at the north of the state owned Moulière forest. The reserve is well worth a visit, especially for people with an interest in Odonata, (Dragonflies and Damselflies) CONTINIUED HERE.

Chris

Spring is in the air - well almost.

Not quite out of the woods yet with a sharp cold spell always possible ‘til mid March but today after all the rain the sun is finally shining, 11°C+ in the shade and life is emerging again even if perhaps only briefly taking a break from hibernation for some creatures.

I have to confess that this is always a somewhat nervous time of year for me waiting to see how many of my occupied bee hives are active. Even though activity in itself is no sure sign that the colony is OK and has a good Queen it’s quite a good indication if they are taking in pollen but even now if a Queen fails before the end of March there is no chance of a naturally mated successor. Most of the hives looked good, all were active and I even managed to get my first sting of the year right on the face, not too happy about that I have to say, never a pleasant experience however much it goes with the job.

Butterflies today were much as to be expected, all the common over wintering species, Brimstone, Comma, Peacock and Red Admiral but good to see them however common they are, after all it wasn't so long ago that the Small Tortoiseshell was a common species in our region, now it's getting quite rare. Also saw a Humming bird hawk moth a species that didn't over winter in our region at one time but increasingly some do now. Carpenter bees are always early risers on a warm sunny day and there were a few of them around “inspecting holes” although it’s hard to believe they could really be laying eggs at this time of year. Found this very pretty and immaculate Ground beetle with very orange legs.

Click on photos to enlarge.

Hazel catkins have been open a while now and many have been washed out with all the rain, none the less there are plenty that are fresh with pollen, goat willow is starting to show and will be open in a matter of days as is the wild plumb blossom.

Found some quite nice clumps of Agile frog spawn, perhaps a little early due to the mild wet winter so far……

…… and at 4.30 a few groups of Cranes totalling some 400 flew over chattering their way north east, (recorded on line with the LPO). All in all a pleasant day with the promise of the big spring rush just around the corner.

Chris

Salamanders, newts and frogs in January.

So far this has been a mild winter in France, particularly so in the west and south west. This always creates a risky situation for amphibians, especially those that are temperature sensitive when it comes to breeding such as the Common frog that is always an early breeder. Although the Common frog, (Rana temporaria), is a species that isn't present in Vienne I understand from talking to people in other Departements that Common frogs started to spawn in December and there are already tadpoles to be seen. Severe cold weather is always likely here until at least the end of February and any sustained freeze will destroy spawn that is on or near the surface or in the case of shallow water that freezes completely any tadpoles.

Salamanders, (salamandra salamandra), will also release their egg sacs or young larvae into the water any time from Autumn 'til Spring if it's mild and my pond currently has larvae in various stages of development with adult females at the waters edge last night.

Click on photos to enlarge.

Also to be seen in the water last night were a few Palmate newts, (Triturus,(Lissotriton), helveticus), perhaps a little early in the season but unlikely to be a problem for them.

Also I saw this little frog, either Edible frog, (Pelophylax kl. esculentus), or Pool frog, (Pelophylax lessonae), no more than 3 to 4cm making its way to the pond, again very early but it would soon find somewhere to hide away should the weather turn very cold.

Plenty to come on Amphibians in the near future.

Chris