Biodiversity in action on Dartmoor

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Marsh fritillary numbers increase by more than 900 per cent

The Two Moors Threatened Butterfly Project has seen marsh fritillary butterfly numbers increase from just 99 to more than 1,000 in three years

Aim: A joint project to reverse the declines of the marsh fritillary, high brown fritillary and heath fritillary on Dartmoor and Exmoor.

How they did it: The decline in the numbers of these butterfly species has been halted (and even reversed) thanks to:

  • Advice and support given to farmers and landowners on more than 140 sites covering over 1,500 hectares of key habitats for the butterflies
  • Working with local community groups, running training sessions and recruiting volunteers to survey numbers of caterpillar webs in the autumn months
  • These groups to carrying out practical habitat management of fritillary sites on more than 71ha of habitat

Results: The number of marsh fritillary has begun to increase on Dartmoor - the species was previously in decline:

  • Previously abandoned sites have been re-colonised and some new ones have also been colonised
  • Just 99 caterpillar webs were recorded on sites in 2007. By 2009 this had increased to 689 and by 2010 it was 1,179
  • The previous rapid decline of the High Brown Fritillary has been halted on Dartmoor
  • 29 farms have agreed to maintain suitable habitats for the butterflies (Higher Level Stewardship agreements)
  • Spin-off benefits include improved conditions for nationally-threatened species such as bog hoverfly, pearl-bordered fritillary, small pearl-bordered fritillary, narrow-bordered bee hawk-moth, dormouse and barn owl

Damselfly goes from strength to strength

About the damselfly: The southern damselfly is rare and declining globally. In Britain it is largely restricted to the New Forest and Pembrokeshire, with a few sites in Hampshire and Wales and isolated colonies in Dorset, Devon and Oxfordshire.

It was first found on Dartmoor in June 1995. Since then two more colonies have been located and sensitive land management and working with local partners has seen its numbers increase rapidly over the last 15 years. New targets have been set for numbers to increase by 2012.

How they did it: By monitoring numbers regularly at the three sites and trying to improve conditions for the damselflies through habitat management.

One of the most successful tools in managing these sites has proved to be Dartmoor ponies, who have transformed two of the areas in the last few years.

Results: Average peak flight numbers of adult damselflies have increased at all known sites from 31, between 1995 and 2004, to an impressive 182 between 2005 and 2010. Also, a further major extension was found to one of the moorland colonies.

Operation wader

Aim: Launched in 2005, this was a five-year project to reverse the alarming decline in the number of breeding wader birds on Dartmoor.

Through monitoring and habitat management, the project aimed to maintain the breeding populations of golden plover (1-3 pairs), dunlin (10-15 pairs), lapwing (18 pairs), curlew (3-5 pairs) and snipe (about 150 pairs), all present in 2004 on Dartmoor.

What is biodiversity?

Biological diversity - or biodiversity - is the name we give to the variety of life on our planet, the result of billions of years of evolution.

Biodiversity is (literally) the web of life - and we're an integral part of it.

So far, scientists have identified about 1.75 million species, mostly small creatures such as insects. In total there are probably more like 13 million species, though estimates range from three to 100 million.

As well as plants, animals and micro-organisms, biodiversity also includes genetic differences within each species - for example, different crop varieties and breeds of livestock.

Biodiversity also means the ecosystems in our deserts, forests, wetlands, mountains, lakes, rivers and agricultural landscapes.

Why we're losing it

In a word: humans.

The loss of species has always occurred but the pace of extinction has accelerated dramatically as a result of human activity.

Based on current trends, an estimated 34,000 plant and 5,200 animal species - including one in eight of the world's bird species - face extinction.

The threats to species and ecosystems include:

  • habitat destruction
  • over-exploitation of natural resources
  • pollution
  • introduction of alien species
  • climate change
  • increasing demands on nature from rising human populations

Biodiversity matters because...

We're a part of it - and we can't live without it.

Most of the oxygen we breathe comes from plankton in our oceans and the forests around the globe.

The fruit and vegetables we eat have been pollinated by bees. The water we drink is part of a huge global cycle involving clouds, rainfall, glaciers, rivers and oceans.

Our diet depends almost entirely on the plants and animals around us - from the grasses that give us rice and wheat, to the fish and meat from both wild and farmed landscapes.

If that's not enough to make us stop and think, the natural world also supplies us with:

  • timber and plant materials for furniture, building and fuel
  • the mechanisms that regulate our climate, control floods and recycle our waste
  • the compounds and chemicals from which medicines are made

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