Baseline monitoring: The first step
For the Wilder Blean project, this means that we need to know which wildlife species are present in West Blean and Thornden Woods, and what the vegetaton and soil looks like before we start introducing our grazing animals.
Kora Kunzmann, Wilding Evidence Ecologist, and her incredible team of volunteers have been working hard to gather this data before the bison take their first steps on Kentish soil later this year.
The themes
Across the three experiment sites, there are 142 monitoring points where an extensive amount of vegetation data has been recorded, including species, abundance, seedling and sapling numbers, tree heights and girth, nectar sources, deadwood volume and structural diversity.
We have also used remote sensing to build 3D models of the vegetation structure that can be compared over time and satellite imagery to analyse trends in vegetation greenness and surface moisture.
Fixed point photography of the vegetation canopy will help measure the quantity or intensity of light reaching the ground, an ecological process of interest relating to bison activity.
Breeding bird, reptile, mammal, invertebrate and butterfly surveying will show us the changes in species number and diversity and ecosystem integrity.
For example, 15 flight intercept traps were used across the woods and invertebrate samples were collected once a month between May and September. After a successful study day learning about identifying invertebrates to order, our fantastic volunteers are now going through all of the samples from last year in order to establish an invertebrate abundance i.e. how many flies, how many beetles, how many bugs did we have each month in each habitat.
We’ll be looking at existing grazing and browsing pressures from wild herbivores to calculate a population estimate to establish the baseline of large herbivore impact.
Alongside heath fritillary butterfly surveys, we are looking at the distribution of their preferred foodplants: Common cow-wheat (Melampyrum pratense) and ribwort plantain (Plantago lanceolata). A lovely group of volunteers recorded abundance score for both plants in 100mx100m squares all over West Blean and Thornden Wood between June and July.
142 soils samples were analysed for carbon in November to establish a baseline of how much carbon is stored in the project area soil ahead of the grazing animal arrival. Samples were also collected by Canterbury Christchurch University interns and will be environmental DNA sequenced for soil fungi and bacteria.
Key findings from the baseline
Birds
A breeding bird survey recorded 34 bird species in the woods, including a number of red-listed woodland specialist species such as the lesser redpoll (Carduelis cabaret) and spotted flycatcher (Muscicapa striata). Red-listed species need our help most urgently. They are threatened with extinction globally and/or have had severe population declines in the UK.
The surveys were undertaken in different areas of the woods so we can monitor any change in bird numbers and diversity between the three experiment areas.
Red-listed nightingales (Luscinia megarhynchos) are a small, secretive birds with a famous song that travel a long way to get to the Blean. They are migratory birds that spend the winter in Africa and summer in Europe and the south east of the UK. The survey found them present in areas of dense undergrowth, typically thick secondary growth in areas of relatively recent coppice of clearfell.
Our team also located 16 lesser spotted woodpecker (Dendrocopos minor), another red-listed species of bird. They are the smallest and least common of the three woodpecker species found in the UK, which makes the Blean one of the best locations for these rare birds in the country. These birds need standing dead wood to survive and this is exactly what we expect the bison to create!
Lesser spotted woodpecker
Nightingale
Spotted flycatcher
Lesser Redpoll
Invertebrates
An astonishing 826 invertebrate species have been recorded in Blean, with beetles, spiders and moths being the top three species found. Unfortunately, 67 species have a conservation status, which means they are threatened with extinction.
The expert found a remarkable number of spiders, 178 different species, which could make the Blean “one of the best and most significant woodland spider assemblages in the UK”!
Some incredibly rare spiders not seen for decades and only ever known in the Blean were recorded, including the Critically Rare Pistius truncates, the first UK record in 20 years of this iconic species, and Walckenaeria mitrata, a genus of dwarf spider not seen in the UK since 2004.
Along with spiders, a single sample of Dissoleucas niveirostris was recorded, a rare anthribid weevil (fungus beetle) not seen in the UK since 1988.
The Blean is a hotspot for the iconic heath fritillary butterfly and was recorded in a third of plots surveyed. They were found mainly in areas with some open habitat across the three experiment areas. Incredibly, considering its rarity across the rest of the UK, it was the commonest butterfly recorded!
Heath fritillary
Walckenaeria mitrata
Pistius truncates