Deer park/Calcareous Grassland

The Deer Park in Selkirk, gifted to Bright Green Nature in 2022, is a species rich calcareous grassland.

But what is a species rich calcareous grassland and why is it important?

Species Rich Grasslands

Species Rich Grasslands are “unimproved” grasslands, which means they haven’t been treated with fertilizers or other chemicals, to make the grass more productive.  While “improved” grasslands become less diverse, as a small number of species grow quickly and out-compete the smaller and slower-growing species, “unimproved” grasslands support a high diversity of native wildflowers, grasses and fungi, which in turn support a high diversity of insects, amphibians, birds and mammals.

Although species rich grasslands co-evolved with traditional farming techniques for 6000 years, we’ve lost 97% of them since we introduced intensive farming methods and commercial forestry less than a century ago.  The 3% that are left are fragmented, leaving isolated species vulnerable to local extinctions.

Healthy species rich grasslands offer a case study in healthy ecosystems, containing a mosaic of habitats (a variety of microhabitats for a variety of species):

  • Tussocks offering shelter for over-wintering invertebrates
  • Small open spaces, which wildflowers need to germinate in Spring
  • Short grasses, providing nesting sites for ground-nesting birds, such as skylarks
  • Long grasses, providing a healthy supply of insects to feed growing chicks.

They also support healthy soils, full of soil micro-organisms, including beneficial bacteria and fungi, vital for nutrient cycling.

We could go on…

Species rich grasslands are vulnerable to all sorts of threats: application of chemicals, fragmentation, over- and under-grazing and afforestation – something to be carefully considered when determining sites for tree planting schemes (commercial or native broadleaf).

Check out our “Deer Park Diaries” for the latest goings-on.

Dear Park Diary 3

Calcareous Grasslands

Calcareous grassland is a category of species rich grassland, which specifically grows on thin, freely draining soils, where the underlying bedrock is limestone or another strongly basic rock (rock which is poor in silica and is rich in certain minerals and in iron and magnesium).  This type of soil is particularly rare in Scotland.

With a pH over 6.5, calcareous grasslands are characterized by a variety of lime-loving plants, which thrive in poor soils, such as Common rock rose Heliantemum nummularium, Maiden pinks  Dianthus deltoides, and herbs such as Wild thyme Thymus polytrichus and Salad burnet Sanguisorba minor. They attract some quite specific (and often rare) invertebrates too:

  • Common rock rose is the most important food plant of the Northern Brown Argus butterfly Aricia artaxerxes.
  • Glow-worms Lampyris noctiluca are rare in Scotland, feeding on small snail species most commonly found on calcareous grassland.
  • Yellow Meadow Ants Lasius flavus are grassland ecosystem engineers, creating patches of bare soil for mosses and wildflower germination. They also farm aphids, which feed on the roots of Common Rock Rose.

What are we doing at the Deer Park?

  • The site is wonderfully biodiverse, so we are conserving what’s already there: monitoring closely but letting nature lead
  • There are also opportunities for restoration, such as the wetlands restoration project and some carefully tree planting
  • We survey the Deer Park regularly and keep an ever-growing list of the species we find  Click here for our latest Species List
  • Deer Park is protected from many of the threats to species rich grasslands, but we need to manage grazing carefully: too much and we would destroy the mosaic of habitats, too little and scrub and trees would encroach.  We use nature-led conservation grazing techniques to try to get the grazing balance just right. We are also working with Borders Forest Trust to control the spread of gorse on the site.
Current Species Total: 264

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