Editorial for the Special Issue Evidencebased options and forward-looking approaches for the conservation and management of diverse wet forests in times of rapid climate change

Helge Walentowski ^1* Danilo E Bustamante ² Jürgen Homeier ¹ Óscar Thiers ³ Stefan Zerbe ⁴

• ¹ Faculty of Resource Management, University of Applied Sciences and Arts (HAWK), Göttingen, Germany
• ² Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas, Chachapoyas, Amazonas, Peru
• ³ Facultad de Ciencias, Universidad Austral de Chile, Valdivia, XIV Los Ríos Region, Chile
• ⁴ Free University of Bozen-Bolzano, Bolzano, Trentino-Alto Adige, Italy

Topic editors: Helge Walentowski, Danilo E. Bustamante, Jürgen Homeier, Óscar Thiers, Stefan Zerbe Worldwide, landscapes, ecosystems, and species are facing unprecedented stress factors in the wake of rapid climate change, without the time they need to adapt on the long term. Accordingly, research is needed which supports evidence-based options and forward-looking approaches for the conservation, management, and restoration of diverse forests. With this special issue, we particularly address forests and forest management in the southern hemisphere, namely in Central and South America. These forests are particularly sensitive to overheating and desiccation.Being productive and biomass-rich, they may pose an increased risk of forest fires in the future. Additionally, their characteristic and indigenous biota and entangled life are fire-intolerant. They thus include the ecosystems that are most sensitive to climate change and are on the threshold of tipping points for irreversible ecosystem degradation.Four studies are presented in our special issue. In the first approach, Bava & Caselli discuss Central European management practice applied to native Patagonian forests in the context of climate change. Climate change strongly affects Patagonian forests, particularly the increasing forests fires, on the one hand, and a lack of forest management on the other hand. At present, the northern Patagonian forests are not under focus of timber production and most of the wood comes from forests more than 2,500 km away. Since the principles of sustainable management of native forests have been developed and applied in Central Europe for more than 200 year it is worth to take adaptation of silvicultural systems that were developed in Central European temperate forests into consideration. The authors highlight that a reasonable recommendation for Patagonian native forests would be an adaptative I n r e v i e w management forest approach that minimizes the changes caused to the forest, an approach that has been applied in other parts of Europe.The second paper from Zaret & Holz addresses forest-peatland ecotones in Western Patagonia, Chile. There, the altered fire regimes, combined with a warmer and drier climate, have been eroding the resilience of temperate rainforests and peatlands and leading to alternative post-fire vegetation communities. In this study, post-reburn field data were collected and modeled in order to examine through which The study revealed that northern Patagonian temperate forests actually store fairly high carbon stocks. However, the current high stand densities of these forests which I n r e v i e w are due to low forest management, may affect their future carbon storage capacity in a warming climate, and they represent a growing threat of high-intensity fires with the risk of a further extension of burned areas in the future.With a fourth paper, tropical mountain rain forests are addressed by Finegan et al.Given that there are no specific approaches for the assessment of their vulnerability at the landscape and local scales necessary for management for adaptation, the authors address the challenge of evaluating the ecological sensitivity of those forest types to temperature. A multidimensional approach in protected areas has been applied over a 440-2,950masl altitudinal gradient in Costa Rica, synthesizing results of a long-term research programme (2012-present). The sensitivity to the current spatial temperature gradient of eleven ecosystem properties is evaluated in three categories which are forest composition and diversity, thermal characteristics of forest stands, and forest structure and dynamics. All eleven ecosystem properties have been found to be substantially sensitive, so changes in their values are expected under rising temperatures. In conclusion, lowland forests may be vulnerable to degradation and biotic attrition, showing current basal area loss, high mortality and climate debts.These studies highlight that ecological research is crucial for the adaptation of forest management to climate change and that there is no solution that fits all. It has been shown that studies along gradients can reveal distinct ecological differences which should be taken into consideration for adaptive management strategies. Adapted nature conservation management must critically assess under which environmental conditions and in which habitats disturbance processes (e.g. wildfires) should proceed unhindered, and where intervention management is the better strategy to fulfil nature conservation objectives. Adapted forest management must incorporate increasing regional and local risk potentials as well as specific and intraspecific drought tolerances and response patterns of trees, their genetic diversity, successional status and plant functional traits in order to ensure ecosystems functions and services.