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| Does Britain have a "balanced" ecosystem? |
Back on the 3rd of April I blogged about the “Fox and the
Leveret” and since then I have had some interesting comments (see comments at
the bottom of that blog). Firstly, thank you for taking the time to post your
thoughts and secondly, how refreshing that we can have a “grown up”, thoughtful
debate on this subject, which so often seems to not be the case on many other forums.
One of the comments particularly caught my eye. “Predation
is obviously a normal and essential part of a 'balanced' ecosystem. Healthy
predator numbers are general indicative of a healthy and productive ecosystem.
The predator-prey relationship, and the fluctuating populations of each, is a
basic ecological principal”.
How true. This is after all, what we are all taught at some
point in our education.
I would however like to add, that although this probably still
holds true in the Serengeti or maybe in some remote parts of South America – does
it really still apply in Britain? Does Britain have a “balanced” ecosystem?
I want to suggest that you walk out of your house, wherever
you live, and look at the landscape that surrounds your chosen abode. Lots of
you will see houses or high rise tower blocks, factories or offices, many of which
may have manicured gardens with striped lawns and a road, busy with cars rushing
past.
If you live in the uplands, you will probably see sheep
grazing the short turf or perhaps conifer trees planted in rows and in the South
West you are quite likely to see black and white dairy cows grazing highly
fertilised green rye grass, or standing in a line in the barn chewing slowly on
silage.
A number of you may look out over arable farmland, with
fields of bright yellow oilseed rape at the moment or straight lines of weed
free winter cereals stretching as far as the eye can see. You might well take a walk out across your
local landscape, following the footpath, occasionally stopping to chat to neighbours
out walking their dogs.
Eventually you reach the isolated wood down in the valley,
where you see the large resident Fallow deer herd and also startle a small Muntjac
deer. A cock pheasant sits on the gate at the entrance to the wood, looking
handsome in the sunlight, while a Grey squirrel scampers up the Sycamore tree
to its hidden drey.
The river is busy with small boats chugging up and down and
fishermen are dotted along the bank, concentrating on the various bits of
equipment that surround them. You stop to talk to one of them and he tells you
that he is fishing for Zander, as there are some really big ones along this
stretch. He also asks if you have seen any water voles lately, as there used to
be lots along this river, but he reckoned that the Mink has had them all.
As you return home, you realise that the wind has now
dropped and the sun is getting low in the sky. Across on the other side of the
valley a farmer is out spraying, making the most of the stillness to avoid
drift. Suddenly, a glint of sunlight, reflected off of the new solar panel farm,
catches your eye making you turn your head away.
On reaching home, Tibbles the tabby cat brings you the kind
offering of a small bird and you put it in the bin, remembering to
re-place the breeze block back on top to stop the Foxes emptying all the
rubbish out.
So, does Britain really have a balanced ecosystem? I think not. Almost every square inch of this
country is influenced by humans in some way.
Some species have thrived under this human management;
however others have not, with some having already been lost forever. There are
a myriad of reasons behind why some species flourish and others find survival more
problematic in this rapidly changing world.
As a conservation adviser, I have to tailor my advice to be realistic
otherwise few would listen to me. I know that farmland birds thrived before
pesticides were introduced back in the 1950s, but with a burgeoning human population to feed, am I really going to tell farmers to stop using sprays. No, but I do have
plenty to say about how to minimise the impact of pesticides on biodiversity.
Likewise, when virtually everything has been tried to help a species
to recover, (good round the year habitat in place and plentiful winter and summer food supply etc) it
sometimes becomes apparent that it is predation by other thriving species that
may be holding numbers down. This for instance seems to be the problem with certain ground nesting birds. Take the Lapwing as
an example.
Despite large amounts of Stewardship money being spent along the Hampshire Avon
water meadows on improving the habitat, Lapwing are not doing at all well. Fledging
of at least 0.70 young per pair, on average, is required for maintenance of a
stable breeding lapwing population, but in the Avon Valley this level of
productivity has been achieved just once in the last seven years. It appears
that predation from Foxes and Corvids, species that are doing extremely well in our
humanised landscape, are the culprits.
So, do we intervene, targeting seasonal control of these
predators on a small area around the breeding Lapwings, as electric fencing off
water meadows, even if it were possible (which it is not), still allows Corvids
in, or do we just stand by and watch the Lapwing become extinct here as a
breeding species, as the Snipe and Redshank have virtually become.
The choice is ours. It is a question of balance.
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