Vegetative Analysis

In our previous threads, we explored the types of grasslands and where to find them in Sidmouth, but how do we truly know if a site is acidic, neutral, or "improved"? The answer lies in Vegetative Analysis—studying the specific plants that choose to grow there.

Soil Chemistry: What the Plants Tell Us

Plants are picky about their environment. By recording which species are present, we can map the underlying geology and chemistry of the Sid Valley.

The Sidmouth Soil Breakdown

The Sidmouth Nature project survey identified plant species associated with three primary soil types:

• Neutral Grassland (48 species): The most common type found locally.

• Calcareous Grassland (42 species): Found where chalk and limestone influence the soil.

• Acid Grassland (6 species): The rarest type in our immediate area.

Local Geological Clues

• Lincombe: This site is a fascinating outlier. It hosts 65% of all calcareous-loving species recorded in the entire survey. This is because it sits exactly where Sidmouth’s red sandstones give way to chalk cliffs.

• Peak Hill: Here, we find the majority of our local acid-tolerant plants. Peak Hill sits on the Upper Greensand layer, which is naturally acidic.

The "Improvement" Fingerprint

Most of Sidmouth’s grasslands are classified as semi-improved. We know this because almost every site surveyed contained a "fingerprint" of four specific species associated with agricultural improvement:

1. Crested Dog’s-tail (Grass)

2. Timothy-grass

3. White Clover

4. Common Daisy

The near-universal presence of these plants suggests that almost all local sites have been treated with fertilizers or disturbed by livestock in their recent past.

The Challenge of "Weeds" and Scrub

A healthy grassland is a constant battle against two forces: its agricultural past and its wooded future.

1. The Legacy of the Plough

Many local sites, like Alma Field, have a high percentage of "agricultural weeds". These are remnants of a time when the land was ploughed for crops. Interestingly, these "weeds" are not necessarily bad; they often provide vital food for Sidmouth's insect populations.

2. The Creep of the Scrub

Because grasslands are plagioclimax communities, they naturally want to become woodland. In Sidmouth, an average of 26.9 scrub species (like brambles and hawthorn) are found on every site. Sites like The Knapp and Combe Wood Farm show the highest degree of scrub, often reflecting how long it has been since they were actively grazed.

Sidmouth’s Diversity Champions

Based on total plant species recorded, here are the top 5 most biodiverse sites in the Sidmouth area:

Site Total Plant Species Notable Feature

Combe Wood Farm 134 Recently transitioned to National Trust "rewilding"

The Knowle 120 Former gardens with many "escaped" species

Lincombe 119 The local stronghold for calcareous (lime-loving) plants

The Knapp 111 An ancient remnant with high neutral soil diversity

Sid Meadow 110 High diversity maintained by historical management