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The EU Biodiversity Strategy 2030 aims to better protect natural ecosystems with high biodiversity and climate change mitigation potential. To achieve this goal, it is crucial to identify forests worth protecting, such as those characterized by long continuity and old age. Here, we propose a robust approach that combines historical maps from the mid‐19th century with remote sensing data to identify areas that have been forested for over 150 years, aiming to reduce the need for detailed and time‐consuming field investigations in potential conservation areas. We tested this approach in a 20,000 km2 region in the Polish Carpathians, an area likely containing many unprotected forests of high conservation value, where historical maps from the mid‐19th century are representative of much of Central Europe. Our results showed that an area of approximately 4200 km2 has been continuously forested since at least the mid‐19th century. Currently, 50% of these forests are outside protected areas, representing an important conservation opportunity. More generally, our approach can support the identification of valuable forests worth protecting before they are lost and provide useful insights for policymakers and stakeholders in the ongoing debate on the challenges of improving forest conservation in the Carpathians, and Europe more widely. [ABSTRACT FROM AUTHOR]

Rivers and other freshwater ecosystems have been severely changed by humans. This resulted in a distinct decline in the abundance of many aquatic organisms, as well as those living in water‐dependent habitats. Our work aimed to study the habitat selection of breeding common sandpipers (Actitis hypoleucos) and the impact of river regulation on the occurrence of this species.Data were collected on a 100‐km stretch of the Vistula River, a semi‐natural, lowland and large European river. The distribution of birds was determined based on two censuses, while environmental variables were collected based on Sentinel‐2 satellite imagery classification, digital elevation model (DEM), digital surface model (DSM) and official data of river regulations.The length of the shoreline of either the river or vegetated islands had a positive effect on the number of breeding territories of the common sandpiper. This indicates the importance of the presence of a natural riverbed with a complex shoreline. Moreover, sandpipers preferred islands over the river shores as nesting habitat. River regulations, such as groynes and riprap, had a negative impact on the abundance of breeding common sandpipers even though the river regulation was not intensive. The negative effect has been persisting for many years after the regulation was implemented, despite the degradation of regulatory structures over this period. [ABSTRACT FROM AUTHOR]

Accurate information on forest tree species composition is vital for various scientific applications, as well as for forest inventory and management purposes. Country-wide, detailed species maps are a valuable resource for environmental management, conservation, research, and planning. Here, we performed the classification of 16 dominant tree species and genera in Poland using time series of Sentinel-2 imagery. To generate comprehensive spectral–temporal information, we created Sentinel-2 seasonal aggregations known as spectral–temporal metrics (STMs) within the Google Earth Engine (GEE). STMs were computed for short periods of 15–30 d during spring, summer, and autumn, covering multi-annual observations from 2018 to 2021. The Polish Forest Data Bank served as reference data, and, to obtain robust samples with pure stands only, the data were validated through automated and visual inspection based on very-high-resolution orthoimagery, resulting in 4500 polygons serving as training and test data. The forest mask was derived from available land cover datasets in GEE, namely the ESA WorldCover and Dynamic World dataset. Additionally, we incorporated various topographic and climatic variables from GEE to enhance classification accuracy. The random forest algorithm was employed for the classification process, and an area-adjusted accuracy assessment was conducted through cross-validation and test datasets. The results demonstrate that the country-wide forest stand species mapping achieved an accuracy exceeding 80 %; however, this varies greatly depending on species, region, and observation frequency. We provide freely accessible resources, including the forest tree species map and training and test data: 10.5281/zenodo.10180469 (Grabska-Szwagrzyk, 2023a). [ABSTRACT FROM AUTHOR]

The changes in vegetation phenology observed in recent decades may have significant implications for carbon, water, and energy fluxes as well as ecosystem productivity. Phenology is an important indicator of a changing environment, and studying species-specific phenology can help understand their responses to varying climate conditions. While satellite-based phenology provides long-term information for large areas, it describes different traits than ground-based phenology. Nonetheless, emerging research on remote sensing-based phenology has shown its usefulness in determining inter- and intra-specific differences, as well as interannual changes. In this study, we examined the potential of the Sentinel-2 time series from 2018 to 2022 in assessing the spring phenology of seven temperate tree species. Three vegetation indices were calculated, namely, the Medium Resolution Imaging Spectrometer (MERIS) Terrestrial Chlorophyll Index, the Normalized Difference Vegetation Index, and the Enhanced Vegetation Index. We examined interspecific variations in the start of the season (SOS) and interannual variability. Additionally, we explored intraspecific variations in spring phenology among common beech stands across an elevation gradient. Our findings reveal substantial differences in Sentinel-2-derived phenology across species, with larch, birch, and hornbeam displaying an earlier SOS compared with oak and alder. The latest SOS dates were observed in 2021, whereas the earliest occurred in 2018 and the difference exceeded 20 days. It corresponded to the diverse spring meteorological conditions in the examined years, with the highest heat accumulation in 2018 and the lowest in 2021. Additionally, the three examined indices showed different phenological curves, with MERIS Terrestrial Chlorophyll Index exhibiting distinct patterns with a delayed start of the spring increase compared with the other two indices. The relationship between elevation and SOS dates was generally positive, but there was high variability in some years. The earliest SOS dates occurred at ~600 m a.s.l. and larger interannual variations were observed for stands located on the highest elevations. These results underscore the potential of Sentinel-2 in monitoring the spring phenology of temperate species, offering insights into inter- and intra-specific variations, as well as year-to-year changes. In the future, longer Sentinel-2 time series will improve estimates and facilitate the tracking of long-term changes. Such advancements hold relevance for forest management, carbon budget predictions, and understanding ecosystem dynamics. [ABSTRACT FROM AUTHOR]