A rapid assessment approach for biodiversity in spruce-dominated riparian buffers and small streams

The biodiversity of spruce-dominated riparian buffers along boreal headwaters is largely unexamined, making effective conservation planning difficult. We developed and implemented a novel rapid assessment protocol to assess biodiversity indicators in 26 streams and riparian buffers in Central Sweden that had been left after clear-cutting. We compared these sites to 10 uncut areas. The protocol was developed using literature and expert knowledge to evaluate biodiversity by calculating a score for each site based on compositional, structural, and functional indicators, taken in riparian and stream plots, and across the whole buffer. We classified the most common types of buffers into four categories: (1) "Discontinuous wide", (2) "Discontinuous thin", (3) "Uprooted trees", and (4) "Few standing trees". Overall biodiversity scores were higher in uncut sites compared to all buffer types, and no significant differences among buffer types were found. Uncut sites generally had the highest scores regarding different biodiversity aspects, except in riparian composition and stream function, where "Few standing trees" scored the highest. PERMANOVA analysis of biodiversity indicators showed no significant differences among buffers and control sites, but univariate analysis indicated differences in riparian plots’ biodiversity scores between uncut sites and "Discontinuous thin" and "Few standing trees ". "Discontinuous wide" showed reduced scores at the whole buffer level due to management practices. Based on our results, we recommend riparian buffers wider than 10 m with stricter regulations for forestry activities in this zone. The protocol should be tested against pristine forests to enhance our understanding of biodiversity in the Fennoscandian region. • We assessed riparian and stream biodiversity indicators in clear-cut and uncut sites. • Uncut sites were significantly higher than clear-cut sites in overall scores. • Clear-cut sites outperformed in the riparian composition score. • Pairwise PERMANOVA showed no differences in biodiversity indicator composition. • Machine tracks and site preparations reduced biodiversity scores in clear-cut sites.