Effects of natural and anthropogenic drivers on land‐cover change and treeline dynamics in the Apennines (Italy)

Abstract

Questions How do climate, topography and human impact affect land‐cover changes, elevation of treelines and dominant tree species composition at multiple spatial scales? Location Apennine Mountains, Italy. Methods At the regional scale (n = 776 municipalities covering 43,000 km2), we assessed the relationship between human demographic processes and forest cover dynamics for the 1990–2012 period using Corine Land Cover maps and a national census data set. At the landscape scale (n = 18 landscape units of 16 km2 each), we tested the effects of site topography on forest cover changes between 1954 and 2012. At the local scale (n = 5,484 sampling points), we extracted the location and species composition of the current treeline (year 2012) using semi‐automatic segmentation methods. We quantified the association of climatic, topographic and anthropogenic variables with the position of upper treelines in the Apennines. Results Regional scale: human population in the Apennines decreased by 3% between 1991 and 2011. During the same time period, there was an increase in the extent of shrublands (+7%) and forests (mixed +4%, conifers +2%, broad‐leaf +1%) and a decrease in the extent of pastures (−9%). Landscape scale: forests expanded more on southwest (+109%) than on northeast (+19%) slopes. Local scale: the mean treeline altitude was 1,755 m a.s.l. Fagus sylvatica L. was the most widespread species (94%), but we also found Pinus nigra Arn. plantations and Pinus mugo Turra shrublands in the central Apennines, and Pinus heldreichii H.Christ in the southern Apennines. Overall, the elevations of the current treelines are negatively related to population density, road proximity and southwest exposures, especially among P. nigra stands. Conclusions At the regional scale, demographic and land‐cover changes provide evidence of widespread land abandonment and forest expansion. At the landscape scale, secondary succession occurred particularly at sites with more solar radiation (SW slopes) and a previous heavier human footprint, followed by a widespread abandonment. Treelines of the dominant tree species (F. sylvatica) were found at elevations lower than would be predicted based on climate conditions alone, suggesting a widespread and strong role of past human influence on the location of treelines. The altitudinal transition from broad‐leaf to conifer species does not generally occur here, as would be expected from a global ecological model. Anthropogenic treelines of the Apennines will react differently than natural climatic treelines to global environmental changes. Models of treeline response to global change in the Mediterranean area should account for land‐use history.

70 Years of Land Use/Land Cover Changes in the Apennines (Italy): A Meta-Analysis

“…Broadleaf forest cover increased after agro-pastoral land was abandoned, especially after World War II. Permanent or temporary population migration from the mountains towards coastal and urban areas was common in the Mediterranean basin, and continues to this day [23,68,81]. The shift from extensive to intensive agricultural systems caused widespread abandonment of crops and grasslands, especially around mountain settlements [21,50,82].…”

Long-Term Changes in the Composition, Ecology, and Structure of Pinus mugo Scrubs in the Apennines (Italy)

“…As observed in the Alps [27,76], such changes should be related to a recent increase in Pinus mugo thicket cover, which occurred following the abandonment of traditional grazing activities in combination with global warming processes. In the central Apennines, the abandonment of traditional grazing and agroforestry activities began after the 1950s [28,41,77] and accelerated in the investigated mountain areas after their inclusion in the national parks system [16,55]. As in other European mountains [26,27,29,30], land use has deeply changed, and the previous landscape that was characterized by Pinus mugo stands scattered over a matrix of secondary grasslands has been replaced by dense Pinus mugo shrublands [28].…”

Factors Driving Rice Land Change 1989–2018 in the Deli Serdang Regency, Indonesia

“…The Deli Serdang Regency is located at 2 • 2 . The highest population density is in Deli Tua District, followed by Sunggal and Lubuk Pakam at 7672, 3109, and 3079 people/km 2 , respectively.…”

“…Land use change is a natural and anthropogenic phenomenon that may occur directly and indirectly at the local, regional, and global levels [1,2]. Land uses changes are categorized as natural phenomena when they are the result of a natural hazard, such as a typhoon or earthquake [3].…”