Vegetation survey

January 20, 2015January 20, 2015 / quarrylifeproject / 2 Comments

The Barton team went back to the lakes in early September 2014 to carry out a vegetation survey. Despite the bad discoveries regarding the invasive species, the surprises were not over yet.

Again the weather allowed the team to work without problems for the whole day on the boat, surveying a total of 6 transects across all the lakes; in particular 2 transects were created in Lake A, 1 transect in Lake B, 2 in Lake C and 1 in Lake D (Site map). The Lake Anew (in red in the map) unfortunately couldn’t be fully investigated due to a time limit and the delay in its flooding. This latter decision was taken by the Hanson-Heidelberg Cement group after breeding birds were found in the area and they would have been affected by the water rise.

The vegetation survey was planned to be carried out creating 2 transects in each lake; however Lake B showed that it didn’t fully required a second transect because of its bed reaching the depth of approximately 2.5-3m with a very long slope, therefore we assumed that 1 transect could provide us a good representation of its vegetation cover. Different situation happened in Lake D which unfortunately was used by boaters for leisure activities and on that day it was not feasible for the team to safely reach another area of the lake for a second transect.

C. Sayer at work even before the beginning of the vegetation survey. (photo: courtesy of M.Benucci)

As mentioned above the results of the survey were not deprived of surprises. The survey was carried out using a double-headed rake (length 25cm), the depth was measured using a portable depth sounder and the light penetration was measured using a Secchi Disk. Of particular interest was eutrophic Lake C which, with its 50cm of light penetration depth a meximum depth of 6 meters and surprisingly the presence of the Short-leaved Water-starwort (Callitriche truncata) which is very local across England (Source: NBN Gateway – https://data.nbn.org.uk/Taxa/NBNSYS0000003621). Furthermore despite its poor light penetration and its water level fluctuations, the lake showed the highest number of species of aquatic plants if compared with the other lakes, even if all at very low abundances.

Aquatic vegetation survey carried out in September 2014. All values follow the DAFOR scale (5=Dominant, 4=Abundant, 3=Frequent, 2=Occasional, 1=Rare).

The rest of the lakes showed a quite spread and substantial proportion of Nuttall’s Pondweed (Elodea nuttallii) which showed highest values in all the sites. Another important parameter assessed during the survey was the colonisation depth. This parameter (highly connected to the light penetration) is an indicator of the status of the lake, because a well established vegetation community across the lake bed is going to positively affect the whole food chain from the benthic community of detritivorous, filter feeders and predators; till the top predators (fish and birds). In the Barton lakes the colonisation depth varied greatly, highlighting the issue of the lakes morphology. In particular 3 lakes were recorded being 5-6m deep with very steep slopes; only 1 (Lake B) showed a depth suitable for a shallow lake with the bottom slowly reaching the maximum depth of 2-3m.

Submerged macrophyte cover (%) in relation to the water depth in each lake along the two transects, T1 and T2. a) Lake A, b) Lake B, c) Lake C, d) Lake D.

As visible from the graph Lake C showed a colonisation depth restricted to the top 50cm of water (confirmed also by the Secchi Disk measurement), and only Lake B presented vegetation cover along the whole transect even if a big drop in the cover percentage was recorded after 15 meters. The data not quantitatively recorded was the actual length of the transects; however few observation were made on site. Lake A and Lake C both presented a submerged cliff only few meters off the shore (less the 5 meters); Lake B didn’t show the presence of a steep cliff along the whole transect which covered approximately 30 meters towards the centre of the lake. Ultimately Lake D, similarly to Lake A and C, presented a steep cliff at about 10 meters off the shore.

More updates soon about the results of the Water Chemistry and the final presentation for the Quarry Life Award.

Updates from Barton

January 7, 2015January 15, 2015 / quarrylifeproject / Leave a comment

Back on the blog after a little while after personal business kept me busy for the last months. The project unfortunately came to an end last November, however there are plenty of updates to share.

Two other surveys have been carried out during the summer 2014. One at the end of August to collect all the benthic invertebrates samples and more water samples, and one at the beginning of September for the vegetation survey. The weather helped the Team throughout the whole period, allowing the whole work to be completed in time and according to the plans.

BENTHIC INVERTEBRATES SURVEY

The benthic invertebrates survey was carried out the 27th August 2014 with 3min netting and 40min live sorting. All the material was labeled and interesting species that shouldn’t have been collected were recorded and placed back. In this way it was possible to record 3 Swan Mussels (Anodonta cygnea) that were put back in Lake A (Site map).

In total 54 species were recorded without much difference in specie abundances across the lakes; however an important discovery was made regarding the record of a second invasive specie, the Demon Shrimp (Dikerogammarus haemobaphes), together with the well established Zebra Mussel (Dreissena polymorpha).

D. haemobaphes (tail close up)

Demon Shrimp tail (D. haemobaphes)

Demon Shrimp head (D. haemobaphes)

Zebra Mussel (Dreissena polymorpha)

The Zebra Mussel had already been recorded in the Barton lakes during the Life in New Lakes study project in 2012; but of the new arrived Demon shrimp there was no sign yet. This latter probably made its way to the Barton lakes from the River Trent where the specie was already recorded in previous years (Source: NBN Gateway website – https://data.nbn.org.uk/Taxa/NHMSYS0021050246).

Importantly the data showed that in most of the lakes (with the only exception of Lake B – Site map) the Demon shrimp occupied already a good portion of the sampled benthic community with high probability also replacing the native Gammarus pulex population.

D. haemobaphes: G. pulex:

Lake A 215 (54.29%) 1 (0.25%)

Lake B 12 (6.19%) 34 (17.53%)

Lake C 92 (25.41%) 5 (1.38%)

Lake D 143 (40.17%) 11 (3.09%)

Despite these negative notes on the 2 invasive species, the rest of the community showed the presence of a good range of interesting species including Molluscs (Lymnaeidae, Bythinidae, Valvatidae and Planorbidae), Leeches, Caddisflies (Phryganeidae and Molannidae) and Water Beetles (Haliplidae and Dytiscidae). In particular, Caddisflies and Water Beetles are also good indicator of water quality, thus showing that the lakes at Barton have the potential for hosting a good community of benthic invertebrates.

Piscicola geometra (Fish leech)

Phryganea bipunctata (larva with its case above)

Haliplidae gen. sp.

In the next days more updates will come regarding the vegetation survey, water chemistry and a summary of the project’s results.

And again at Barton Lakes.

July 31, 2014July 31, 2014 / quarrylifeproject / Leave a comment

New fieldwork for the “Life in New Lakes” Project; as after the 6th of June and another short visit at the beginning of July, the team composed by David Ryves, Roger Flower, Chris Carter and Marco Benucci went again at Barton Lakes last Tuesday 22nd July.
The day couldn’t appear any better, as the sky was clear and the sun was a constant presence during the whole time. Once arrived at the Lake C, they started to prepare all the equipment surrounded by many Azure Damselflies, at least one couple (male & female) of adults Demoiselle (either Calopteryx virgo or Calopteryx splendens) and possibly a Brown Hawker (probably Aeshna grandis). During the morning we had also the judges of the project who came to visit us; in this way we had the chance to show them some of the main issues recorded on Lake C and we showed them also the artificial reeds newly installed.

In general Lake C showed immediately some changes since the last visit; in fact while during early July the water level had been found lower of an estimated 40cm from June, this 22nd of July the level seemed having increased again of an estimated 10cm. Another of the changes recorded was the water clarity, which despite the clear and sunny day was extremely low, showing a very small portion of the lake bed visible from the shore. This condition, not present in the other lakes, has been confirmed later during the day with the measurement with the Secchi Disk who showed a water penetration restricted to only 60cm, a value much smaller in comparison to the previous one. The consequences that this small light penetration is causing on the biota became evident with the collection of one sample with the Heckman grab. At a depth of about 5m, the sample collected in this way showed that the sediment is composed only by black silt, without any sign of vegetation and with only few Phantom Midge larvae (Family Chaoboridae); even the grappling hook thrown at about 3m from shore failed in finding (at least in that area) any sign of vegetation.

The artificial reeds have been controlled and few samples have been collected to assess the biota that established on them; and the results showed again the presence of Volvox colonies together with colonies of Gloeotrichia echinulata (a green-blue algae).

Left: colonies of Gloeotrichia echinulate; Right: Gloeotrichia echinulate colonies under higher magnification (Images courtesy of Chris Carter)

In order to exploit fully the visit, we also decided to collect only 2 kicksamples, one from Lake C and one from Lake D, to start assessing the structure of the aquatic invertebrate communities in the 2 lakes. While live sorting the samples, some main differences have been already spotted as the great presence in particular of Leeches in Lake D, which can be explained by the presence of Swans, Coots and Zebra Mussel (Dreissena polymorpha). Lake C instead showed the presence of Waterboatmen, Shrimps and Snails (Physidae, Bithynidae and Planorbidae); however more will be published as soon as we will properly ID the speciemen.

Sampling for aquatic invertebrates at Lake C (Photo taken by David Ryves)

The other ponds and lakes as well showed some important changes, as Lake B which experienced the almost entire disappearing of the Blanket Weed that during June was covering almost 2/3 of the water surface. The established community of Canadian Gees is well visible on Lake B. The community is composed by at least 20 Geese, and they seem to spend their day on Lake B, returning to Lake C only later in the afternoon.

Left: view of one section of Lake A; Right: Lake B with the Canadian Geese (Images courtesy of Marco Benucci)

First Survey

July 4, 2014July 31, 2014 / quarrylifeproject / 1 Comment

Last 6th June 2014 the project has started with an initial survey. The team composed by David Ryves, Roger Flower and Chris Carter, has been on site to carry the first survey and to collect some water samples. The margins of the lakes appear green and flush, in full growing period, even if on the background is visible one last excavator standing on the bare ground of the last extraction pit. This latter pit however very soon it is going to be at the centre of the attention of the team, because after the last 2,000 tonnes of gravel have been extracted the pump will be stopped and the whole area will be flooded by groundwater and will provide a new lake to be studied. The main advantages of this event will regard the opportunity to assess the colonisation by flora and fauna immediately after the flooding, so hopefully providing an insight in the steps of this process for newly created lakes.

Top Left: Preparation of new “Reed stems” at Lake C; Top Right: Sampling at Satellite Pool 1 (NW of Lake C). Bottom: The last extraction pit to be flooded in July.

The results from this first survey appear promising and very interesting with already some surprises, because a Diatoms belonging to Pandorina genus has been found in the samples. The identification seems to point towards the specie Pandorina morum var. major (Ivengar 1933), which represent a new record for British Isles; however further analysis are required to confirm the exact specie ID. Other interesting findings included other Diatoms, as a Volvox colony and a Colacium vesiculosum; the latter found attached to the body of a nauplius larvae of a Copepod.