Jon Cranfield

Archive for the ‘the big pond thaw survey 2011’ Category

Hanna Combo finally arrives!

In Garden pond, Observations, the big pond thaw survey 2011, the garden pond blog, Wildlife on February 11, 2011 at 6:16 pm

I have recently purchased a pH/Conductivity Meter as suggested by Pond Conservation. The meter enables a measurement of how much ‘pollution’ or ‘nutrients’ are within ponds which I visit. I have tested my garden pond and I plan to visit several water bodies around the town to see each of them compare. The river in our town is a chalk stream – assumed to be in pristine condition. However I feel that the meter will tell a different story.

Creating ponds according to Jeremy Biggs from pond Conservation is the best way to bring back clean water habitats to our countryside. I have a very clean pond in my garden and I hope to create more as a result of my volunteer and professional work with amphibians. See the photo of the meter


The pond in January 2011

In Garden pond, Observations, the big pond thaw survey 2011, the garden pond blog, Wildlife on January 6, 2011 at 10:35 am

We are into the new year now. The garden pond has lost a reasonable amount of its water after the thaw. The Big Pond Thaw Survey 2011 has been filled in for the pond. A few dead invertebrates have been spotted including an adult water beetle, a few water beetle larvae and the mayflies – the pond olives. Over on the Garden Pond Blog Jeremy Biggs has been reporting on the end of year news story from the Environment Agency – Looking at the real situation around the state of the UK’s rivers – Telegraph Article –

Jeremy Biggs Letters in the TimesIndependent

This has led to people tweeting Garden Pond Blog 1 Environment Agency 0 – Habitat Aid for example –

Nick Mann
Habitat_Aid Nick Mann 

Garden Pond Blog 1 Environment Agency 0:
Pond Conservation is another organisation which I hope to support through being a supporter – through my Company Herpetologic ltd after reviewing who we currently support we have managed to make a saving by stopping support for one organisation that we feel we are not getting any value for the money we give them – we can now put money towards excellent charities such as Pond Conservation & ARC Trust instead.

More pond myths…..

In Garden pond, Observations, the big pond thaw survey 2011, the garden pond blog on December 3, 2010 at 4:56 pm

A national charity has this advice for garden pond owners in relation to iced over ponds

‘prolonged freezing stops gases from moving in and out of the pond, leaving the water susceptible to a buildup of toxic gases and chemicals released as animal and plant matter continues to decompose. This can seriously damage the pond ecosystem, affecting a number of animals (not least frogs, which can die of so-called ‘winterkill’). To avoid this, remember to make holes in the ice during frosty weather’

You can do this by leaving a pan of hot water on the ice surface to melt a circular hole. Alternatively leave a ball floating in the water the previous day, and remove this once the pond has iced over.’

Dealing with nutrients the following advice is given for dealing with algae blooms

‘If your pond lacks water fleas then (with permission) consider asking a nearby pond owner for a small amount of silt and water, but be very careful not to transfer any plant fragments with it (see page 12).’

This is interesting advice as previously it has been stated that frog spawn should not be swapped

‘advise that you do not donate your frogspawn to other gardeners, or collect frogspawn to deposit in your own garden pond. The advice is given to help national efforts to stop the spread of invasive pond plants, animals and amphibian disease. In nearly all cases, amphibians will turn up of their own accord, often breeding in the first pond year’

So it is not okay to introduce frog spawn but it is okay to introduce water and silt which would possibly have the same potential to spread amphibian diseases like Rana virus and Chytrid fungus

People have considered the problem of introducing frog spawn to new ponds – the conclusion was that over limited distances it is probably beneficial for frog populations to have new genes introduced into new populations – this would have to be within gardens and not into the countryside

more to follow…..

The big pond thaw survey 2011

In snow news, the big pond thaw survey 2011, the garden pond blog, Wildlife on December 1, 2010 at 11:47 am

Pond Conservation is running its big thaw survey again this winter after a successful survey in 2010 – you can see the results here

I am going to monitor my small garden pond this winter and I will be reporting back to the survey through the online form

From the survey some interesting results were collected and pretty much provided evidence that the usual advice about ponds may not be the best advice

From the results and other research by Pond Conservation

the following advice has been given in relation to amphibian deaths in ponds due to ice

What can we do to reduce amphibian deaths during cold spells?

What are the practical implications of the survey for creating and managing garden ponds so their inhabitants can survive in the cold winter months?

There are several suggestions we can take from all the findings so far:

1. Ponds shouldn’t be too deep for their area. Shallow ponds – less than 30 cm (1 foot) are more likely to have higher oxygen levels in the water which helps amphibians, so a good pond shape is wide and shallow – a saucer rather than a tank.

This is the exact opposite of much of the standard advice, which says that ponds ‘should be deep to protect them from freezing solid’. In fact, we know that most ponds didn’t have more than more than a few centimeters of ice, even during the very coldest days of the 2009-10 winter – so ‘freezing solid’ isn’t the problem.

2. A large build-up of leaves and sediment on the pond bottom is probably not good news – almost certainly because this de-oxygenates water. This is especially a problem in ponds which are small and deep.

3. Having plenty of plants in the pond throughout the winter is a good way of improving oxygenation. Underwater plants, including mosses (which don’t die-back in winter) are ideal, although it’s worth remembering that algae, both filamentous and unicellular (the sort thatcolour the water pea-green) also produce oxygen.

4. There isn’t any evidence that making holes in the ice, or breaking the ice, can prevent amphibian deaths. This is not surprising, as most amphibians hibernate at the bottom of ponds. Oxygen diffuses very slowly into still water, at about 2 millimeters a day! So it takes over 6 months for surface oxygen to reach the bottom of a 50 cm deep pond.

5. BUT – If you have a pump, and you think the pond might have low oxygen levels, it is worth making a surface hole and keeping the pump running so that the water is stirred up – this can move oxygen from the surface to deeper waters. A shallow pond with lots of underwater plants won’t need a pump.

6. If the pond freezes and then snow falls on top of the ice, clearing some snow off the ice to make a ‘sunlight-hole’ can help. But this is only likely to work if your pond has lots of underwater plants (or algae) which can then oxygenate the water.

The first frozen frogs have been reported through this last round of snowy weather

I hope that I can assess the numbers of invertebrates that have died over the frozen period – I will also be seeing whether the pond freezes solid as it is only 20cm deep!