Understanding the dynamics of forest understorey: Combination of monitoring and legacy data reveals patterns across temporal scales

• Published in: Journal of vegetation science Vol. 31; no. 5; pp. 733 - 743
• Main Authors: Hédl, Radim, Chudomelová, Markéta, Bello, Francesco
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.09.2020
• Subjects: Abandonment; Annual variations; Biodiversity; canopy; Coppicing; Czech Republic; Data collection; Dynamics; Forest management; forest understorey; Forests; legacy data; Monitoring; Plant communities; Plant diversity; Plants; seasonal dynamics; Seasonal variations; semi‐permanent plots; Species diversity; Species richness; temperate forest; Temperate forests; temporal scales; temporal variation; Temporal variations; understory; vascular plants; Czech Republic
• ISSN: 1100-9233; 1654-1103
• DOI: 10.1111/jvs.12882

Aims The dynamics of plant communities varies across temporal scales. A correct understanding of temporal patterns is crucial for the interpretation of monitoring outputs. Focusing on the understorey community of an ancient coppice at three temporal scales, our aims were to: (a) assess the link between year‐to‐year variations and a decadal successional change; (b) estimate how seasonal cyclical dynamics could interfere with the changes at interannual and decadal scales; and (c) account for the effects of coppicing restoration. Location Mt Děvín, S Moravia, Czech Republic. Methods Composition of a temperate forest understorey was monitored in 26 permanent plots on a year‐to‐year basis for a decade (2008–2018) and monthly (2015–2016). Adjacent semi‐permanent plots (23 in total) were resurveyed in 1953–2003. The three scales of temporal variation were statistically analyzed and compared looking at the vascular plant diversity (species richness) and compositional turnover (dissimilarity measures and patterns in multivariate space). Results Each of the three temporal scales captures specific patterns in herbaceous understorey species richness and turnover. The interannual variation shows fluctuations rather than trends and is lower than the magnitude of changes on a decadal scale. However, canopy thinning was responsible for rapid changes compatible with the long‐term trend of biodiversity decline following the abandonment of coppicing decades ago. The seasonal dynamics showed a distinct cyclical development typical of temperate forests. It exceeded the magnitude of interannual changes, pointing at the potentially significant source of error from the timing of data collection. Conclusions Comparison of the monitoring and legacy data revealed complex patterns in the forest understorey dynamics. Contrary to general assumptions, the short‐term dynamics of forest understorey can be significant. It is recommended that monitoring designs consider not only permanent plots but also resurveys of semi‐permanent plots. Considering more than one temporal scale will improve our understanding of the plant community dynamics. We studied the dynamics of a species‐rich temperate forest understorey at three temporal scales: seasonal, interannual and decadal. All scales showed significant turnover in species richness and composition. Our results point out that the monitoring of plant communities should consider multiple temporal scales and appropriate types of plots to reduce the temporal sources of error.