by Hayley Partridge, Jordan Holmes and Daniel Hosking
BSc Conservation Biology
Here's the next instalment from our three placement students working with Devon Wildlife Trust. In July, they carried out vegetation, hedgerow, bat and river invertebrate surveys, and took soil samples associated with key butterfly host plants. They also took part in events with the general public, for educational purposes and raising awareness about conservation efforts in North Devon.
This month at Devon Wildlife Trust, we’ve been working on National Vegetation Classification, which meant improving our plant ID skills more. To do an NVC survey, a quadrat must be placed on the ground and every species within it identified and its percentage cover in the quadrat estimated. When we have done five quadrats in each habitat, we can analyse the species composition and find which plant community it is.
We attended our first team meeting and there are lots of upcoming projects, including agricultural shows and events for schoolchildren.
Following our NVC surveying, we went to Avon Valley and carried out hedgerow surveys. Each hedgerow can be more than 100 m long, and both sides must be surveyed for height, width, species, gaps, signs of nutrient enrichment or mammals, large trees, dead wood, and the overall shape and management of the hedgerow. The hedgerow surveying was a lot of walking but the weather was really hot and sunny, and we got better at identifying trees.
After this, we worked on our Devil’s Bit Scabious project. We took soil samples from county wildlife sites where scabious is present and samples from sites where it isn’t. This is because about 10,000 seedlings are waiting to be planted, and we need to find out if there is a common factor that means either encourages or discourages scabious. Devil’s Bit Scabious is the plant which the Marsh Fritillary butterfly larvae feed on, so if we can establish more scabious populations, hopefully the range of the butterflies will grow.
Linked to our work on the County Wildlife Sites, we attended a training day where we learned about what makes a County Wildlife Site, how they are designated and surveyed, and we made two site visits to work on species and habitat identification.
As part of the Avon valley project, we also looked at bats in the area, due to there being a nearby Greater Horseshoe bat colony. Greater Horseshoe bats are common in southwest England and Europe, but are rare in the rest of the United Kingdom. To determine what bat species are present, we placed an Anabat (a device which records bat vocalisations over all frequencies) overnight in one of the fields. Additionally, we walked the site at night with bat detectors, which are tuned to one frequency and allowed us to hear the different bat calls. When we were surveying with the bat detectors, we managed to find a greater horseshoe bat which is generally at a frequency of 80khz, pipistrelles which were around 45khz and we believe we heard a lesser horseshoe bat at 108khz. The Anabat recorded greater horseshoe bats, pipistrelles and noctules.
We have also done more Riverfly surveying this month, where we use kick-sampling to find river invertebrates and larvae. We surveyed three sites and found stonefly, mayfly and caddisfly larvae, as well as shrimps, worms, leeches, snails and even fish. We use the species we find as indicators of river water quality, as many species are intolerant to nutrient enrichment or pollution, and our results showed good water quality in these sites on the river Torridge.
At the end of July we attended the Woolfardisworthy agricultural show. We were part of a stand about the North Devon Biosphere, which involved talking about the Nature Improvement Area project we are currently working for, and interacting with the public in order to raise awareness of the project. Also we were approached by landowners who were looking for grants to carry out work, or potentially applying for an environmental stewardship scheme, as well as people who were simply interested in becoming members of Devon Wildlife Trust.