The edge of two worlds: A new review and synthesis on Eurasian forest‐steppes

Abstract

Aims: Eurasian forest-steppes are among the most complex non-tropical terrestrial ecosystems. Despite their considerable scientific, ecological and economic importance, knowledge of forest-steppes is limited, particularly at the continental scale.Here we provide an overview of Eurasian forest-steppes across the entire zone: (a) we propose an up-to-date definition of forest-steppes, (b) give a short physiogeographic outline, (c) delineate and briefly characterize the main forest-steppe regions, (d) explore forest-steppe biodiversity and conservation status, and (e) outline foreststeppe prospects under predicted climate change. Location: Eurasia (29°-56°N, 16°-139°E). Results and Conclusions: Forest-steppes are natural or near-natural vegetation complexes of arboreal and herbaceous components (typically distributed in a mosaic pattern) in the temperate zone, where the co-existence of forest and grassland is enabled primarily by the semi-humid to semi-arid climate, complemented by complex interactions of biotic and abiotic factors operating at multiple scales. This new definition includes lowland forest-grassland macromosaics (e.g. in Eastern Europe), exposurerelated mountain forest-steppes (e.g. in Inner Asia), fine-scale forest-grassland This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Underground deserts below fertility islands? – Woody species desiccate lower soil layers in sandy drylands

“…Forest-grassland mosaics occur all over the world at the interfaces of forested and grassy biomes and take up various forms, such as forest-steppes and savannas (Scholes and Archer 1997, Erdős et al 2018a), wood-pastures created by forest thinning and subsequent grazing (Bergmeier et al 2010, Hartel et al 2015), grasslands recently encroached by woody species (Van Auken 2009, Grellier et al 2013), and partially afforested drylands, where trees are planted to reduce soil erosion, or to increase atmospheric carbon sequestration (Yosef et al 2018, Bastin et al 2019). Being prime ecosystem engineers, woody species profoundly affect biodiversity and ecosystem functions, including services for human populations.…”

High resistance of plant biodiversity to moderate native woody encroachment in loess steppe grassland fragments

“…The studied grasslands are classified as 6250 Illyés & Bölöni, 2007). Ancient grasslands cover various types of loess deposits and are situated in naturally occurring forest steppe openings (Borhidi, Kevey, & Lendvai, 2012;Erdős, Ambarli, et al, 2018;.…”

“…The studied loess grasslands in the region grow on chernozemic soils which are developed on loess bedrock. Loess grasslands were historically embedded in a mosaic landscape of the forest steppe zone (Erdős, Ambarli, et al, 2018;. This historical landscape was characterised by dry loess grasslands, semi-dry grasslands both with and without shrubs, and fragments of open and closed steppic scrubs and forests.…”

“…The establishment of scattered trees and shrubs also increases the medium to large-scale habitat heterogeneity (see e.g., Zhou et al, 2019), which has proven to be beneficial for sustaining high species richness through providing multiple types of microsites for species establishment both for plants (Kesting et al, 2015(Kesting et al, , 2009Tamme, Hiiesalu, Laanisto, Szava-Kovats, & Pärtel, 2010) and insects (Eldridge et al, 2011;Koch, Edwards, Blanckenhorn, Walter, & Hofer, 2015). In forest steppes, a heterogeneous habitat mosaic of grassland and forest patches in transition between closed forest and open grassland (Erdős, Ambarli, et al, 2018;, most dry-grassland species can also grow near to shrubs and trees but some shade-tolerant and forest species are also favoured (Pykäla, 2005;Erdős, Tölgyesi, Körmöczi, & Bátori, 2015). With increasing cover of woody species, the area of fringe communities at the edge or transition zone between grassland and shrub-and/or tree-dominated vegetation increases, which could also be beneficial for biodiversity (Kesting et al, 2015;Erdős, Ambarli, et al, 2018;.…”

“…In forest steppes, a heterogeneous habitat mosaic of grassland and forest patches in transition between closed forest and open grassland (Erdős, Ambarli, et al, 2018;, most dry-grassland species can also grow near to shrubs and trees but some shade-tolerant and forest species are also favoured (Pykäla, 2005;Erdős, Tölgyesi, Körmöczi, & Bátori, 2015). With increasing cover of woody species, the area of fringe communities at the edge or transition zone between grassland and shrub-and/or tree-dominated vegetation increases, which could also be beneficial for biodiversity (Kesting et al, 2015;Erdős, Ambarli, et al, 2018;.…”