Air humidity, soil moisture and soil chemistry as determinants of the herb layer composition in European beech forests

Abstract

Question: What role does air humidity play as an environmental factor for the abundance and distribution of temperate woodland herbs? Location: Beech forests on calcareous soils in southern lower Saxony, central Germany. Methods: The abundance of woodland herb species and total herb cover were investigated in 60 plots with contrasting exposure, slope angle and relief type. On all plots, air humidity, air temperature, soil moisture, photosynthetically active radiation, pH (H2O) and concentration of salt‐exchangeable Ca, Mg and K were measured. Species‐environment relationships were analysed with multiple regression analysis and CCA. Results: Air humidity (RH), soil moisture and the concentration of exchangeable Ca and K, but not light, C/N ratio and the concentration of exchangeable Mg were identified as the most important abiotic factors influencing the cover of the most abundant plant species and total herb cover. RH varied substantially across the different forest floor site types and influenced species abundance independent of soil moisture. In several species (including Mercurialis perennis and Impatiens noli‐tangere), RH was found to be a key environmental factor. Other species such as Aegopodium podagraria and Lamiastrum galeobdolon depended more on elevated soil moisture, while RH was less important. Conclusions: This study showed that the distribution of widespread temperate woodland herb species depends on high air humidity, and that certain sensitive species do not occur at sites with reduced air humidity even though soil moisture is high. Thus, high air humidity and ample soil moisture are key abiotic factors in beech forests on calcareous soils. Shade level (PAR) was found to be of secondary importance.

Response of carabid beetles (Coleoptera: Carabidae) and spiders (Araneae) to coastal heathland succession

“…Air temperature was recorded during the whole study period from May 2008 to May 2009 (apart from 18 incompletely measured days) with data-loggers (''i-buttons''; Dallas Hygrochron Temperature/Humidity i-Button DS 1923-F5) equipped with a self-constructed radiation shield (Leuschner and Lendzion 2009). One logger was installed in the centre of each plot at middle height of the field layer.…”

Evaluating Short-Term Impacts of Forest Management and Microsite Conditions on Understory Vegetation in Temperate Fir-Beech Forests: Floristic, Ecological, and Trait-Based Perspective

“…An extensive list of past studies (e.g., [18][19][20][21]) has provided evidence that factors related to stand structure (e.g., forest canopy) drive the composition and diversity of the understory strata by exerting strong controls on resource quantity and heterogeneity [11,14]. However, at finer spatial scales, environmental factors other than light transmittance, which is directly influenced by silvicultural measures, contribute to the patterns of species distribution and abundance, notably, topography, microclimate, nutrient availability, soil moisture, and soil acidity [22,23]. As emphasized by the authors of [24], site-specific characteristics have a larger role to play in defining understory plant diversity than the management disturbance itself.…”

Syntaxonomy and ecology of forest vegetation in the Štiavnické vrchy Mts (Central Slovakia)

“…Significant influence of soil water supply and available nutrients on species composition of forest vegetation has been already published (e.g. Douda 2008;Leuschner and Lendzion 2009;Slezák and Petrášová 2010).…”