Unexpected long-range edge-to-forest interior environmental gradients

Abstract

We examined the relationships between distance-to-edge and environmental factors inferred from mean plant indicator values across large distance-to-edge and patch size gradients.Floristic composition, landscape metrics and site variables (climate, soil and forest management) were collected on 19989 plots in 1801 forest patches in Northern France using the French National Forest Inventory. Statistical models were applied to mean plant indicator values (MIV) from Ellenberg and Ecoplant databases for soil pH, soil nitrogen (N), soil humidity (F), light (L) and air temperature (Ta) using distance-to-edge and forest patch size as predictors. The five mean indicator values significantly varied with distance-to-edge and MIV.pH, N and Ta decreased over distances in excess of 500 m. Consistent very long edgeto-interior gradients were also detected for site variables. The distance-to-edge effect remained significant after controlling for site differences, especially for MIV.pH and N.Significant edge-to-core gradients of MIV were detected over much larger ranges than previously recognised. Neither the presence of an ecological boundary between forest and the surrounding matrix, nor microclimate, soil or forest management heterogeneity within forest patches can fully explain this long edge-to-interior gradient observed in MIV. Two hypotheses are discussed for MIV.pH and N: (1) soil eutrophication, due to atmospheric N deposition, which could occur deeper into forest cores than previously acknowledged; (2) land-use legacies, as the periphery of ancient forests is more often occupied by recent forests where former agricultural practices have irreversibly modified topsoil properties. Land use history data would help identify the drivers underlying these long-range edge gradients.

Past landscape explains forest periphery‐to‐core gradient of understorey plant communities in a reforestation context

“…up to 800-1100 m (Thimonier et al, 1992;De Schrijver et al, 1998;Kennedy & Pitman, 2004;Hofmeister et al, 2013;Pellissier et al, 2013). eutrophication of terrestrial ecosystems (Bernhardt-Romermann et al, 2007;Wuyts et al, 2008;Berg es et al, 2013). up to 700-800 m Hofmeister et al, 2013;Pellissier et al, 2013).…”

Site Selection for Restoration Planning: A Protocol With Landscape and Legislation Based Alternatives

“…In this regard, enhanced connections and resilience zones are strategies to be considered. Furthermore, the enlargement fragments template, which prioritizes filling invaginations of irregularly shaped fragments, can be particularly useful for reducing edge effects and consequently benefits sensitive species (Bergès et al 2013).…”

“…Connectivity is a key factor in the maintenance of individuals in fragmented habitats , as well as in (re)colonization dynamics (Gilbert-Norton et al 2009), and is consequently relevant for metapopulation persistence. Edge effects are known to reduce the amounts of available habitat within a given patch for sensitive species (Bergès et al 2013), although fragment edges promote important exchanges of individuals, seeds, propagules and nutrients, which ultimately influence resilience/regeneration around patches (Holl & Aide 2011).…”

Landownership is an unexplored determinant of forest understory plant composition in Northern France

“…Plant trait approach (Table 1) was mainly based on plant indicator values that have been extensively employed as indicators of abiotic conditions (Diekmann, 2003;Bergès et al, 2013). Ellenberg et al (1992) and more recently Gégout et al (2005) defined a set of indicator values for plants across central Europe and France, respectively.…”