More amphib adventures at Malham

This bank holiday weekend I spent another day at Malham Tarn FSC, surveying the ponds on the moss for amphibians.

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Malham Tarn

Last time we were there we saw lots of frogs and found newts in one of the many ponds near the boardwalk. Since frogs are the earliest amphibians to get going in the spring generally, we had been hoping that this visit would see lots more newt activity being warmer and later in the season. However, given the recent cold snap and overnight temperatures of below zero we were not too optimistic!

Newts are much less active at low temperatures, and the general advice is that at temperatures below 5°C, the survey effort required is much greater and detectability falls dramatically.

This time, as well as the ponds we knew of, we had two more to survey which had been newly dug two years ago. We were told about these by the National Trust ranger who said that they had been dug to improve the breeding habitat for dragonflies.

On Saturday morning we scoped out the new ponds and did the pond habitat and environmental surveys, we also did some netting for inverts to give a water quality assessment. The seasonal difference really showed here as the water in the ponds was alive with midge larvae this time. We were also excited by the number and diversity of the case caddis fly larvae we found!

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Case caddis from the family Phryganeidae

We also did a quick visual and netting survey of the other ponds for frogspawn and tadpoles. In  most of the ponds, the spawn had hatched already although the tadpoles we did see were still relatively small. In many of the ponds the spawn appeared to have been degraded to some degree and many unhatched eggs remained with clouded brown/grey/white centres. A possible reason for this is the acidity of the water which was generally between pH 4.5 and 5.0.

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Tadpole, unhatched eggs and an empty egg are visible in this picture

Since the temperature was forecast to be so cold, we did not have many traps this time, and intended only to put a few in the ‘newt pond’ and the new ponds. After setting the traps and waiting for dark, we started torching the ponds. In the cluster including the newt pond, we saw only one frog although he torchlight did make it easier to spot frogspawn below the surface too.

Moving onto a larger pond, we saw lots of fish and a couple of times “ooh, I saw something!…ah, it was probably just a fish.”

Then: “There’s a newt! Definitely as newt! Female!” we watched a definite newt swim across the bottom of the pond and thought “Oh, bother! Why didn’t we bottle trap this one?!”

After the initial sighting we saw 6 more newts, mostly appearing female although we saw one probable male with dark webbed back feet. Unusually for females at this time of year they all appeared quite slim and small rather than swollen with eggs so the ID we gave was by no means positive… Were they juveniles? Why were they not breeding? Were there not enough males?

After the unexpected success of the night, we ventured out in the morning to collect in the bottle traps. In the ‘newt pond’ cluster, we had no luck, only catching a few tadpoles. Moving onto the new ponds we had no expectations, after all these ponds were only two years old and we hadn’t detected any newts in the ponds out on the fen last time.

Once again we were surprised. In the first bottle trap was a female palmate newt and an eft!

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Female palmate newt showing the pink colour of her chin

The next planned visit to Malham is in 3 weeks and instead of narrowing down the survey field in any way we’ve managed to extend it. Despite the cold weather we found newts in places we weren’t expecting and next time with warmer weather and more active newts there might be even more to see!

Sadly I’m not booked to go on the third trip due to other commitments but I hope I might be able to pop up just for a day, I don’t want to miss out!

 

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Newts galore

Sorry, more newt stuff… well, ’tis the season!

So this week I’ve been surveying for newts at some Pondnet sites in the Lower Aire Valley and I’ve also assisted with my first professional survey. Mid-April to mid-May is newt season proper and it’s all kicking off! Lots of first for me too so bear with, it’s all exciting!

On Sunday evening we torched and set bottle traps at ponds at Rothwell Country Park near Leeds. We set the traps at each pond while it was still light and as it grew dark we worked our way back round all the ponds, torching for newts. We saw a few by torchlight and also a handful of toads. This confirmed that smooth newts were still present at the site and we were not expecting any great crested newts there.

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At one of the pond we were surprised to hear a frantic scrabbling noise as we moved around the pond and discovered a water shrew in one of the bottle traps. Shrews have a very high metabolism and need to eat a lot to stay alive, luckily we could release it unharmed and we removed all the bottle traps from that pond. Since bottle traps are often a death sentence for water shrew, they should not be used in ponds where they are known to be present. The water shrew we found was probably a new record for the site and lovely to see, they are the largest UK shrew and have very dark fur and distinctive white tufts of fur on their ears.

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Poor little water shrew (Photo credit: Kate Wright)

The next morning we found we had caught a handful of smooth newts in bottle traps and I got my first proper look at both male and female smooth newts. We also had several great diving beetles and in a couple of ponds quite a few bottles of fish!

Great diving beetles are huge, and easily recognisable. About an inch long with a pale border around the edge of the elytra and thorax they are vicious predators and feed on other water invertebrates and small fish. Any newts that are unlucky enough to get caught in a bottle trap with one of these probably wouldn’t come off too well either!IMG_20160411_091228820_HDR-COLLAGE.jpg

The fish were three-spined stickleback, a common native fish. Large populations of fish are not a good sign for newt populations though since they eat the eggs and larvae. In one of the ponds, we also saw four goldfish which had not been recorded there previously… someone’s unwanted pets no doubt.

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Monday morning also brought me my first toad spawn. Unlike frogs who lay clumps of spawn, each encased in its own jelly covering, toads lay their spawn in jelly strings. These are wrapped among vegetation at the water surface and can be quite difficult to spot!

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Finally onto the newts then! We caught both male and female smooth newts in the bottle traps. The males are in full breeding regalia at the moment with a continuous wavy crest along the back and tail and distinctive black spots with a pale ‘flash’ along the bottom of the tail. Both male and female smooth newts have orange spotty bellies and the spots often continue onto the throat and chin (unlike palmate newts).IMG_20160411_084050515_HDR.jpg

 

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Male smooth newts belly (Photo credit: Kate Wright)

On Tuesday evening we surveyed a site on the Lines Way near Great Preston. On this site there are usually two ponds and a long ditch which has been good for smooth newts in the past. There were known to be great crested newts on this site so I was quite excited!

The area where the ponds should be is currently flooded so instead of nice separate ponds, the entire area was covered in water up to about 10inches deep. We set bottle traps around here as best we could then once it had got dark enough we started torching the ditch. The Lines Way is a footpath and cycle path that follows the route of an old railway. Since the ditch runs right along next to the path it’s not really suitable for bottle trapping since they are at risk of being tampered with or removed by members of the public.

As there were 6 of us there with 3 torches between us, we worked our way down the ditch in pairs. Each pair counted increasing numbers of smooth newts, with the largest count being 329, a site record! We also saw several toads and I saw my first crestie, a large male, although it took a bit of following him along the ditch to get a good look!

After the success of the ditch we headed to the ponds area to see what was there. We were rewarded with lots of great crested newts, 40 counted in total from torching. This was up from aout 10 counted last year! Several of these were just in the ditch right alongside the path as the whole area was so wet and we got a good look at them.

After the success of the evening, we were keen to get back in the morning to see what was in the bottle traps.  Disappointingly, a lot of them didn’t catch anything. We ended up with 2 smooth newts and one female crestie. It’s amazing how different they look in daylight compared with the torchlight of the  night before. Under torchlight they appear quite pale and spotted while in the day their skin looks very dark and warty with white speckles towards the belly.  Underneath they are bright orange with irregular black patches. Hopefully I’ll have the chance to see and handle some more of these before the season is up!

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We did also see lots of newt eggs at this site. They are laid on leaves which are then usually folded over to protect the egg from sunlight and predation. Egg searching is another technique for assessing newt presence at a pond. To see these eggs we did not need to unfold any leaves but if eggs are found in folded leaves, they are then vulnerable so once one egg has been found, further leaves should not be unfolded. Great crested newt eggs tend to be whiter than smooth or palmate newt eggs which are more of a beige/grey colour.

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I think that’s just about enough for today so more on newt surveys to come!

Easter Weekend at Malham

More amphib adventures as promised.

This Easter I was at Malham Tarn Field Studies Centre with two fellow MSc students. The aim of the trip was to survey the many ponds on the fen for amphibians. The first step was to check NBN Gateway for any existing records. There were not many amphibian records for the site and as far as we knew there had not been any systematic surveys carried out so it was quite exciting to be part of establishing the site records.

The Field Studies Centre very kindly agreed to accommodate and feed us for the weekend so on Friday morning we set off, and despite getting embroiled in the bank holiday traffic we got to Malham in the early afternoon ready to make the initial site assessment and measure variables to calculate the great crested newt Habitat Suitability Index (HSI).

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When we got there, we found that there were many more ponds than we had anticipated from a preliminary search based on satellite images. Most of them appeared to be deliberately cut into the peat on the fen, although we have no idea what the purpose of these holes was – it’s on the list to ask the National Trust ecologist when we meet him next time! Many of the ponds were very deep with vertical sides, or even overhanging banks, so we were very careful not to fall in! Several were alive with frogs as we approached, although we only recorded two clumps of spawn. The adult frogs themselves were difficult to count as they tended to hide themselves away as soon as we approached.

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For the habitat survey, we recorded a number of variables including size and permanence of the ponds, vegetation, presence of fish and waterfowl, water turbidity, pH and conductivity, underlying geology and surrounding habitat. For the GCN HSI a few other factors allowed calculation of an index using the system developed by Oldham et al. (2000) which is used nationally to assess sites for GCN potential.

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After the initial site assessment, and some well earned tea and cake, we headed out to set the bottle traps for the evening. This was a completely new technique to two of us so it was fascinating to see them. There’s nothing complex about a bottle trap, it’s just a 2l soft drink bottle with the top cut off and inverted to make a funnel. This is attached to the body of the bottle and a bamboo cane passed through the sides of the bottle to allow it to be fixed in place in the ponds. We distributed the traps among the ponds, a few metres apart, spaced around the edge with a bubble of air caught inside… adult newts aren’t able to breathe under water and must come to the surface for air.

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After setting out the traps (and meticulously recording what we’d placed where!) we had dinner, and once it was dark we set out to do some torching. We saw several more frogs, mostly in amplexus (mating pairs) and our first glimpse of a possible newt turning and diving into the dense spagnum vegetation lining the sides of the pond.

In the morning, excited, we headed down to the ponds to collect in the bottle traps and see if we had caught anything. Sadly there were no newts in our traps, although we had caught several frogs… a first for our resident expert!

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After breakfast we headed out to the ponds again to assess the vegetation surrounding the ponds to describe the general area and to do some netting for invertebrates. The invertebrate diversity of ponds is a good indicator of the pond quality and a factor used to assess GCN habitat suitability. We did not find a huge number of inverts in any of the ponds, although it is possible that there is seasonal variation in invert activity and we were simply too early. There were plenty of caddis fly larvae and lesser water boatman though.

This is also when we found our first newts! Sarah, an expert after a childhood spent fishing for newts in her grandmother’s pond, managed to find both an adult male palmate newt and an eft (juvenile). These were in the same pond that we caught a glimpse of a newt the previous night and the presence of the eft showed there was a breeding population present, exciting stuff!

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A wet day was spent indoors trying to identify our vegetation and invertebrate samples before heading out into the rain to set the nights bottle traps. This time we decided to concentrate our efforts on the cluster of ponds where the ‘newt pond’ was located. A bit more experienced this time, we set the traps around the pond edges, this time facing into the submerged vegetation at the sides rather than into the open water at the edges of the ponds. Newts like to walk along the bottom of ponds, and generally it is best to set bottle traps so that they are on the bottom. Since these ponds are so deep with vertical edges, this is impossible . The newts we had found earlier and seen on the previous torching attempt appeared to be hidden in the sphagnum lined sides of the pond so we hoped that by setting the traps this way we might have more success.

Since the weather was not good and the results from torching previously had been limited, we decided not to go out torching on Saturday evening and instead had a lovely pub meal at the Lister Arms in Malham before heading to bed.

Early on Sunday morning (still in the rain) we checked and collected the traps. From the first few ponds still nothing but frogs. Then, excitement building, came the ‘newt pond’. This time we had three newts! Two adult male and one pregnant female palmate newt. IMG_20160327_075748450.jpg

Palmate newts (Lissotriton helveticus) can be distinguished from smooth newts (Lissotriton vulgaris) by the absence of colour in the skin on the underside of their head. Both can have orange spotty bellies but palmate newts have a pink chin, this is the only way to distinguish between females of each species. Male palmate newts in breeding season have frilly webbed toes on their hind feet and a thin filament on the end of their tails. In the individuals we caught these are not very distinct, possible because it is still early in the season, so on our next visits these should be more pronounced.

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There will be two more visits to Malham this year, I will be going on the next one at the end of April and it’ll be exciting to see if we see more newts. The presence of lots of mating frogs and little spawn shows that it is still early in the season up at Malham. Being higher and colder than down in Leeds, it is likely that things are a bit behind there. Newts tend to get going a few months behind frogs and toads, peak time being April-May so hopefully we’ll get a lot more activity next time!

It’ll also be interesting to see if we can find newts in any of the other ponds. In the ‘newt pond’ area there are 12 other ponds that we surveyed, all within an area about 25 x 50m with some very similar to the ‘newt pond’ so it seems odd if none of the others are home to a newt population.