Where forests meet grasslands: Forest-steppes in Eurasia

Despite the ecological, economic and conservation importance of forest-steppes, a continental scale synthesis of this complex ecosystem has been lacking. In a recent review, we compiled scattered knowledge about Eurasian forest-steppes in a new synthesis, proposed a new forest-steppe definition, reviewed how the biogeographic position of this ecosystem is perceived by different authors from different regions, delineated the main regions based on criteria of flora, physiognomy (i.e., vegetation structure), relief, and climate,and explored the conservation importance of forest-steppes. Here we complement some of the key findings of the review and illustrate some topics with further specific examples.(VLID)463075

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

Peter, Torok/0000-0002-4428-3327; Anenkhonov, Oleg/0000-0001-8633-7154; Batori, Zoltan/0000-0001-9915-5309; Magnes, Martin/0000-0002-5453-5735WOS: 000442660900001AimsEurasian 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 forest-steppe prospects under predicted climate change. LocationEurasia (29 degrees-56 degrees N, 16 degrees-139 degrees E). Results and ConclusionsForest-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), exposure-related mountain forest-steppes (e.g. in Inner Asia), fine-scale forest-grassland mosaics (e.g. in the Carpathian Basin) and open woodlands (e.g. in the Middle East). Using criteria of flora, physiognomy, relief and climate, nine main forest-steppe regions are identified and characterized. Forest-steppes are not simple two-phase systems, as they show a high level of habitat diversity, with forest and grassland patches of varying types and sizes, connected by a network of differently oriented edges. Species diversity and functional diversity may also be exceptionally high in forest-steppes. Regarding conservation, we conclude that major knowledge gaps exist in determining priorities at the continental, regional, national and local levels, and in identifying clear target states and optimal management strategies. When combined with other threats, climate change may be particularly dangerous to forest-steppe survival, possibly resulting in compositional changes, rearrangement of the landscape mosaic or even the latitudinal or altitudinal shift of forest-steppes.Orszagos Tudomanyos Kutatasi AlapprogramokOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [K 119 225, PD 116114]; Hungarian Government [EFOP-3.6.1-16-2016-00014]; National Youth Excellence Scholarship [NTP-NFTO-16-0623]; NKFIH [K 124796, K 119225]; Russian Federal Budget [AAAA-A17-117011810036-3]Orszagos Tudomanyos Kutatasi Alapprogramok, Grant/Award Number: K 119 225 and PD 116114; Hungarian Government, Grant/Award Number: EFOP-3.6.1-16-2016-00014; National Youth Excellence Scholarship, Grant/Award Number: NTP-NFTO-16-0623; NKFIH, Grant/Award Number: K 124796 and K 119225; Russian Federal Budget, Grant/Award Number: AAAA-A17-117011810036-

Chrysidide nouvelle [Hym.]

Buysson Robert du. Chrysidide nouvelle [Hym.]. In: Bulletin de la Société entomologique de France, volume 12 (8),1907. p. 138

The Influence of Region of Interest Heterogeneity on Classification Accuracy in Wetland Systems

Classifying and mapping natural systems such as wetlands using remote sensing frequently relies on data derived from regions of interest (ROIs), often acquired during field campaigns. ROIs tend to be heterogeneous in complex systems with a variety of land cover classes. However, traditional supervised image classification is predicated on pure single-class observations to train a classifier. This ultimately encourages end-users to create single-class ROIs, nudging ROIs away from field-based points or gerrymandering the ROI, which may produce ROIs unrepresentative of the landscape and potentially insert error into the classification. In this study, we explored WorldView-2 images and 228 field-based data points to define ROIs of varying heterogeneity levels in terms of class membership to classify and map 22 discrete classes in a large and complex wetland system. The goal was to include rather than avoid ROI heterogeneity and assess its impact on classification accuracy. Parametric and nonparametric classifiers were tested with ROI heterogeneity that varied from 7% to 100%. Heterogeneity was governed by ROI area, which we increased from the field-sampling frame of ~100 m2 nearly 19-fold to ~2124 m2. In general, overall accuracy (OA) tended downwards with increasing heterogeneity but stayed relatively high until extreme heterogeneity levels were reached. Moreover, the differences in OA were not statistically significant across several small-to-large heterogeneity levels. Per-class user’s and producer’s accuracies behaved similarly. Our findings suggest that ROI heterogeneity did not harm classification accuracy unless heterogeneity became extreme, and thus there are substantial practical advantages to accommodating heterogeneous ROIs in image classification. Rather than attempting to avoid ROI heterogeneity by gerrymandering, classification in wetland environments, as well as analyses of other complex environments, should embrace ROI heterogeneity

Growth Decline Linked to Warming-Induced Water Limitation in Hemi-Boreal Forests

<div><p>Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (<em>Pinus sylvestris, Larix sibirica</em> and <em>Larix gmelinii</em>), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.</p> </div

Correlations between the standard chronology and temperature (light grey bars), precipitation (dark grey bars), and PDSI (black bars) during 1937–2005 regarding <i>P. sylvestris</i> (A), <i>L. sibirica</i> (B) and <i>L. gmelinii</i> (C).

<p>The dotted lines indicate the 95% confidence intervals.</p