Back to mountain forests: historical ecology to measure rewilding
By resurveying historical vegetation plots on Italian Apennines (Southern Europe) a comprehensive picture of the ongoing rewilding dynamics at broad forest landscape scale was firstly described for Mediterranean mountains. After fifty years of forest protection, the study revealed a general diffusion of shade adapted species underlying the ongoing processes of forest mesification as the main driver of long-term vegetation changes from past human impacts.
Human footprint
Walking into mountain forests we often observe signs of past human land use: for centuries man has shaped almost the totality of European mountain forests for exploitation of resources, as timber harvesting and charcoal production, or for allocating lands to agriculture and pastures. These long-term impacts have generated deep changes such as forest fragmentation and simplification of ecosystems. In this framework, the few remnant old-growth forests, untouched by man by very long time, play an outstanding role for preservation of natural processes, acting also as refugia for demanding, narrow-range species threatened by human disturbances.
Nevertheless, in the last decades something is changing.
Tracing forest rewilding
In Italy the widespread abandonment of mountain areas in the last fifty years has generated a decrease of forest harvesting practices. What are the effects of these dynamics on forest systems so long shaped by man? Is nature coming back?
To answer these questions, we need historical monitoring data that may allow for a quantitative measure of changes over time. To this aim, historical ecology, with the resurvey of past vegetation data, is providing a picture of the ongoing dynamics in several ecosystems, suggesting possible future trajectories of changes and thus helping to orient conservation strategies. However, few of such studies are available for Mediterranean regions and Southern Europe, thus hampering to quantify long-term changes in a crucial area for biodiversity.
A new study for a relevant area
A research recently published on Journal of Vegetation Science (Long term changes in Italian mountain forests detected by resurvey of historical vegetation data, doi.org/10.1111/jvs.12939) contributes to fill this gap, quantitatively assessing forest dynamics in a rewilding, yet overlooked mountain area of Southern Europe. The study has been carried out during the Ph.D. project of Chiara Lelli, from the BIGEA Dept., University of Bologna, supervised by Prof. Alessandro Chiarucci and Prof. Juri Nascimbene, in collaboration with Prof. Gianluca Piovesan of the DAFNE Dept., University of Tuscia, the Foreste Casentinesi National Park and the Arma dei Carabinieri—C.U.F.A. - Reparto Biodiversità di Pratovecchio (Arezzo, Italy).
The research was based on one of the oldest vegetation dataset in Europe available for the Italian Apennines, which was retrieved, digitized and resurveyed. The original surveys were carried out by Pietro Zangheri, a major Italian naturalist, between 1934 and 1961, along a 1000 m altitudinal gradient. The study area is of biogeographical concern, being located at the northern edge of the Mediterranean biome, and the remarkable altitude gradient provides a natural laboratory for studying the impact of global changes in a rewilding forest landscapes. The original surveys also include plots recorded within the Sasso Fratino strict nature reserve, the first to be established in Italy in 1959 in a residual old-growth beech stand. Sasso Fratino is located in the core area of the strict nature reserve of Foreste Casentinesi National Park and since 2017 is a component of Unesco World Heritage serial site (whc.unesco.org/en/list/1133/). These wide gradients of elevation and naturalness allowed considering also the importance of site location, forest continuity and marginality as drivers of changes that need to be taken into account when planning conservation actions for restoration of mature forests.
First steps of a long-lasting recovery process
This research evidenced the loss of cultural landscapes, as chestnut orchards or beech coppices, where the slow recovery of natural processes are transforming the landscape to a more mesic state (forest mesification). This gradual recovery of forest naturalness during the rewilding of mountain landscapes takes a very long time and the human footprint is still strongly evident. Thus, the collected data are describing an early stage of a long term process where site location, forest continuity and marginality are the main drivers of changes. These findings should be taken into account when planning conservation actions for restoration of mature forests. The ongoing rewilding process may overcome the challenges of sustainable development, contributing to the goals of protecting threatened species and habitats and mitigating the impact of global warming.
For more information:
Long term changes in Italian mountain forests detected by resurvey of historical vegetation data
Chiara Lelli Juri Nascimbene Davide Alberti Nevio Agostini Antonio Zoccola Gianluca Piovesan Alessandro Chiarucci
First published: 16 August 2020 doi.org/10.1111/jvs.12939
More information:
doi.org/10.1111/jvs.12939
Provided by University of Tuscia
