An agricultural pilot scheme has successfully reduced phosphorus in five East Perthshire lochs in an internationally important wildlife site.

Excess phosphorus can cause the growth of algae, which reduces water clarity and oxygen levels and leads to less plant and animal life in lochs.

The project is a combined effort led by Scottish Natural Heritage (SNH), with advice from the Rural Payments and Inspectorate Division (RPID), monitoring by the Scottish Environment Protection Agency (SEPA), and involving 14 land managers.

For five years, the land managers have been working with SNH to protect the chain of five lochs between Dunkeld and Blairgowrie from excessive phosphates, mainly from inorganic fertilisers, soil and manure being washed into the lochs.

In the only management scheme of its kind for SNH, 14 of the land managers who farm the 5877 hectares in the catchments of lochs Craiglush, Lowes - itself a Scottish Wildlife Trust Reserve - Butterstone, Clunie and Marlee, have changed some of their land management practices.

They have reduced the application of inorganic phosphate fertiliser, adhered to phosphate budgets and waste management plans, ploughed cereal crops later than usual, created grass buffers, reverted to grass in flood risk fields, made farm steading improvements, and fenced watercourses from cattle.

Before the management scheme started, SEPA detected very large peaks of phosphorus in the lochs. It is believed this was caused by high rainfall events which would have washed soil and manure off fields into burns and the lochs.

But once the management scheme started and farmers carried out the various mitigation measures, no big peaks of phosphorus were recorded in the lochs - even though there were some very heavy rainfalls.

Denise Reed, SNH area manager, said: "This project proves that shifting the way land is managed can conserve the rich wildlife in our lochs. We have encouraged the farmers involved to transfer to the SRDP to continue the terrific work they've been doing.

"On the national level, the lessons learned from this project will help us develop long-term SRDP measures to improve the conditions of lochs and rivers throughout Scotland."