Assessment of regulating ES potential of lowland riparian hardwood forests in Poland

Lowland riparian hardwood forests are valuable habitats protected by EU Habitat Directive (EU code: 91F0). Today, in most areas across Europe they are extremely rare due to deforestation, drainage and river engineering. The remaining small forest patches are important parts of riparian ecological corridors and biodiversity hotspots, and provide valuable ecosystem services (ES) to humans. However, unlike other forest types, due to their rarity and often low accessibility their ES potential has not been duly recognized and assessed to date. In this work we propose a set of biophysical indicators to assess the regulating potential of riparian hardwood forests. Indicator values were obtained through extensive field work and direct measurements carried out on selected test sites located along the middle Vistula River. The specific objectives of this work were: (i) to estimate the potential of riparian hardwood forests to provide 11 regulating services and to identify interactions among them; (ii) to examine the effects of forest and environmental attributes on individual ES; (iii) to determine ES drivers. Our results clearly show that riparian hardwood forests may be regarded as multiservice hotspots. Their regulating potential has proved to be substantial and in case of many services higher than the potential of other forest ecosystems. However, disruption of the natural water regime due to the absence of flooding and artificial drainage reduces their potential mainly for water-related regulating services (e.g. water treatment). On the other hand, more mesic habitats are beneficial for melliferous plant species and thus for wild pollinators. Most of the strong and significant interactions among the studied regulating services are synergistic. The high ES potential quantified by the biophysical ecosystem-condition-related indicators can be used effectively to promote the maintenance or restoration of this type of forests. The outcomes of our research suggest that protective actions should focus on ensuring adequate soil-moisture conditions which determine the specificity of these ecosystems.

Automated summary

Lowland riparian hardwood forests are valuable habitats protected by the EU, but are extremely rare in most areas across Europe. They are important parts of riparian ecological corridors and biodiversity hotspots, providing valuable ecosystem services to humans.