Friday 28 February 2014

Week 6, Part 2: Sheepish Explanations of Ecology

This post is all about sheep. It features adorable, springtime lambs; suckling mothers and family gatherings. No, they’re not “wild” but they have their role to play in sustaining the ecosystem of Westbrook Hay. In fact, conservation grazing is used widely, including at the National Nature Reserve, Wicken Fen, in Cambridgeshire. If it’s good enough for one of Britain's most biodiverse habitats, supporting literally thousands of rare and endangered species, then it’s good enough for us.

Essentially, grazing cattle are one tool used for succession management. If you know what that is, you can skip this next bit and just enjoy the cute pictures of sheep. Otherwise, I’ll explain (as only someone with no qualifications in ecology or natural sciences can do!). If you take a strip of barren, lifeless land, over time, eventually, weedy plant species will take root. They require minimal nutrients and are the first step to a developing ecosystem. Where there are plants, invertebrates will inevitably be drawn and, as these live, reproduce and die off, the soil’s nutrients improve and further plant species can move in. There is an inescapable progression to the way in which the land, its habitat and the species it sustains change. Weeds are naturally succeeded by grasses; and grasses by shrubs; shrubs by hedges and finally trees will dominate the landscape. As the habitat changes so will the type and species of organism (flora and/or fauna) which can survive there.

Simplistically, the final stage, or climax, of ecological succession is forestation. Trees are wonderful but woodland is only one type of habitat and you won’t find organisms which thrive in reed beds or grasses or low-growing, open scrub, or any other habitat you can think of which isn’t woodland, in such situations. It is for this reason that succession management is so important. Diversity of habitat leads to a rich diversity of flora and fauna (biodiversity)....and that’s why there are grazing sheep on Westbrook Hay!

Practically, the sheep help to maintain and improve the mixed clay, gravel and flint based soil grassland of the slopes of Dellfield and Preston Hill. As someone more knowledgeable about the site explains, “the sheep keep the coarse and invasive grasses short so that smaller wildflowers have a chance. By rotating the grazing we can help ensure a variety of wildflowers through the spring and summer. In turn, butterflies and day flying moths have a variety of sward lengths for egg laying and wildflowers for nectar. The lovely Small Coppers and Small Heaths, for instance, enjoy the really short grass." Of course, this person was keen to point out that "grasshoppers and crickets need long grass!! So variety is the key" and, hey presto, we’re back at habitat diversity, biodiversity and the central role of succession management, in all its guises. Finally, with all this talk of butterflies, moths, grasshoppers and crickets, I'm reminded that there is a lot to look forward to over the coming weeks as Spring unfolds.

I was going to write about the (Blackface) Norfolk Horn sheep but I’ve run out of steam for this week and will have to leave that one for you to reference if you’re interested. My third and final instalment is short but pretty and I'll upload that over the weekend. Now, for the extravagant array of sheep photographs (that really does sound weird!)

Family Gatherings


Suckling Mothers

Cute Lambs

Ear Nibbling!



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