In this guest post, Filipe S. Dias provides a summary of his recent paper “Effects of forest certification on the ecological condition of Mediterranean streams“.

Recently cleared riparian vegetation.
Recently cleared riparian vegetation.

In Mediterranean regions, streams and riparian habitats support dense and productive forest ecosystems that contrast strongly with the adjacent semi-arid habitats. During the hot and dry Mediterranean summer these habitats provide food and water to several animal species and harbour a wide variety of plant species. However, riparian habitats are often threatened by livestock grazing, vegetation clearing, soil mobilization and channelization which often restrict them to narrow strips of vegetation.

Riparian vegetation beside a stream after five years of certification
Riparian vegetation after five years of certification

The implementation of Forest Stewardship Council (FSC) certification for cork oak woodlands in Southern Portugal requires landowners to change the way they manage streams in these ecosystems. In FSC-certified cork oak woodlands, streams are usually placed in Conservation Zones – areas within forest management units whose purpose is to maintain or restore forest biodiversity and where livestock grazing and vegetation clearing are prohibited or heavily reduced.There over 90 000 hectares of cork oak woodlands under FSC certification and this area is expected to grow in next few years, but the impact of forest certification on the ecological condition of streams has never been studied.

A riparian gallery by a least-disturbed and well-conserved stream.
A riparian gallery by a least-disturbed and well-conserved stream.

We used the Stream Visual Assessment Protocol (SVAP) to compare the ecological condition of reaches located in certified areas, with that of reaches located in non-certified areas and with that of least-disturbed reaches. The study took place in Portuguese part of the Tagus river basin, where there are over 348 787 hectares of cork oak woodlands, of which 73 330 hectares are FSC certified. We found that reaches that had been under forest certification for five years had a significantly higher cover by riparian vegetation, fewer signs of bank erosion and a higher availably of microhabitats (Fig. 2), when compared to non-certified reaches (Fig. 3). Moreover, the overall ecological condition of these reaches was similar to that of least-disturbed and well-conserved reaches. Given the large and increasing area of forest certification in cork oak woodlands, we suggest the positive effects observed at the reach scale may spread across the hydrographic network in the medium-to-long term.

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