Evaluating the Contribution of Trees outside Forests and Small Open Areas to the Italian Landscape Diversification during the Last Decades

Abstract

Land use by humans strongly alters the landscape mosaic, either by reducing or increasing its heterogeneity. One of the most recent and widespread land use changes in Europe has been the spontaneous reforestation of marginal agricultural lands. These primarily affected small landscape patches, such as trees outside forests (TOF) and small open areas (SOA), often represent the most diversifying features of landscape' structures. Nevertheless, only small-scale studies can be found in the literature and thus it remains a relatively unexplored issue. Integrating inventory and cartographic approaches, this work assesses changes in abundance, coverage, and average size of small patches in Italy between 1990 and 2013. Main results showed an overall increase in number and coverage of small patches during the reference period. The average patch size remains unaltered for TOF but decreases significantly for SOA, due to trees encroachment and canopy cover increasing in forests. Our findings confirm the important changes in Mediterranean land mosaics and contribute to a better understanding of current conditions and recent trends regarding TOF and SOA. The integrated approach has proven to be helpful for the large-scale assessment of small patches dynamics, representing a viable monitoring tool to encourage the inclusion of small patches in landscape policy and planning.Forests 2018, 9, 701 2 of 13 within the land mosaic have a strong impact on ecological processes and, in turn, on the functioning of socio-economic and ecological systems [5,6].Recently, humans have driven landscape dynamics much more than natural evolution [7,8]. Since the Industrial Revolution, intensive farming systems and urban land expansion at a global scale have increasingly altered the structures and functions of the existing landscapes at an unprecedented rate [9]. The anthropogenic influence is even more marked in landscapes characterized by higher levels of heterogeneity and built by centuries of human activities and modifications, such as those in the Mediterranean area [10][11][12]. During the last decades, the Mediterranean landscapes have indeed experienced a general decrease of agricultural lands, mainly due to their abandonment, followed by tree encroachment and subsequent woodland expansion [13,14], particularly in mountain and less profitable marginal lands [15][16][17]. Oppositely, the agricultural intensification and the expansion of urban areas, which usually follow a high scattered and fragmented spatial pattern, urban sprawl, and urban sprinkling [18,19], are occurring in lowlands and plains [20][21][22]. These phenomena are strictly interlinked and can alter the sustainability of such systems, especially in the medium-long term [22].Tree encroachment can have both positive and negative implications in terms of ecosystems' functionality and their capacity to provide ecosystem services (e.g., [23][24][25][26][27][28][29]). The risk associated with landscape homogenization [30] is particularly relevant if combined with urban expansion, ...

Census and Dynamics of Trees Outside Forests in Central Italy: Changes, Net Balance and Implications on the Landscape

“…This trend in TOFs does not coincide with the trends studied for the whole Italian territory [24], confirming that the dynamics of these areas are related to changes in the fine-grained microstructure of historic landscapes [22].…”

“…Recent research has evaluated the characteristics of specific composition and wood volume, highlighting the importance of TOFs in terms of biodiversity and ecosystem services [23]. Another important role of TOFs is to reverse the effects of land use/land cover change (LULCC) to maintain ecosystem functionality and resilience in landscapes [24]. Microhabitats are an extensive biodiversity stock [25]; studies highlight the importance of these for biodiversity conservation [26] and their vulnerability to external pressures [27].…”

The Role of Trees Outside Forests in the Cultural Landscape of the Colline del Prosecco UNESCO Site

“…The same survey reports an increase in TOF in the period 1990-2013 of 17.1% in their number and of 27.4% in their overall surface, while the average surface remained unchanged [48]. According to Sallustio et al [49], TOF represent essential elements of the green infrastructure network in many Italian landscapes, but the expansion of big and continuous forest patches on marginal lands and, on the other side, the agricultural intensification, can lead to a decrease in TOF and in the historical landscape mosaic structures. Similar findings have been reported for southern Spain and Italy by Hidalgo et al [50], where residual "island forests" could act as "stepping stones" in the local ecological network.…”

Tree occurrence in agricultural landscapes of peri-urban Kigali in semi-arid context of Rwanda

“…This trend tends to make agricultural ecosystems less resilient and more vulnerable to global environmental changes (Foley et al, 2005;Tscharntke et al, 2011). Agricultural landscapes have been transformed over time due to growing demands of natural resources, which affects the spatial distribution patterns, structure and composition of the agricultural land mosaic (Sallustio et al, 2018). In this context, trees on farms ("agroforestry") is often depicted as a high potential solution for the increasing demand for food security and livelihoods of small-holder farmers, resilient to the multiple stressors that agricultural systems are currently facing in the global South (Berkum, 2023;Borelli & Conigliaro, 2014;Iiyama et al, 2018a;Waldron et al, 2017).…”