In Mediterranean ecosystems, the anthropogenic impact makes the preservation of plant biodiversity critical. Indeed, human pressure can be responsible for the depletion of vascular flora and the reduction in biomass production. Within the Campania region, some areas of the Vesuvius National Park are particularly exposed to the anthropogenic impact due to seasonal tourism. As a matter of fact, during spring and summer, a considerable amount of tourists pass through the Park areas, also with vehicles, thus causing the formation of dust clouds which are deposited over the vegetation close to the paths (Fig. 1). The main aim of this study is to analyse whether the deposition of dust on the leaf lamina of Centranthus ruber (L.) DC. subsp. ruber (Caprifoliaceae) plants can induce changes in leaf anatomy and in the efficiency of photosynthetic apparatus. The study was conducted on C. ruber plants growing at three sites, similar for environmental conditions and species composition. For each site two different sub-areas were considered: 1) the first, located along the side of the road, where a high deposition of dust (HD) was recorded on leaves, and 2) the second, placed at least five meters far from the path, where plants were subjected to a very low deposition of dust as control (LD). The amount of deposited dust was quantified at the study sites, in different periods of the year, characterized by different tourism access (spring-summer-autumn). Being C. ruber widespread throughout all the area of Vesuvius National park, it was chosen as an environmental indicator, making possible to evaluate the potential negative effects of the dust deposition on both anatomical and ecophysiological features. Functional traits in leaf lamina (e.g. stomatal size and frequency, percent of intercellular spaces in mesophyll) were quantified through light microscopy on fully-expanded leaves collected in summer (Fig. 2). Ecophysiological traits (chlorophyll a emission, photosynthetic pigment concentration and leaf traits) were carried out as well on fully expanded leaves, during spring and summer. Our results showed that HD leaves enhanced a pool of anatomical and photochemical traits allowing to overcome the effect of dust. Dust-induced changes in photosynthetic pigment content and stomata features were recorded. The overall analysis suggests that the greater amount of dust raised from the paths, shielded the leaf lamina: indeed leaves developing near the paths formed morphoanatomical traits as “shade leaves”. We infer that the phenomenon of dust deposition acts as a screen on leaves thus shading the photosynthetic apparatus from the light excess during summer. Although this phenomenon is positive for the optimization of C. ruber growth in these specific sites, the response of other species must be analysed to evaluate possible dust-induced vegetation dynamics consequent to possible species-specific adaptive capability.

Anthropogenic impact in the Vesuvius National Park: effect of dust accumulation on leaves of Centranthus ruber (L.) DC. subsp. ruber

De Micco V.;Izzo L. G.;Amitrano C.;Aronne G.;Arena C.
2017

Abstract

In Mediterranean ecosystems, the anthropogenic impact makes the preservation of plant biodiversity critical. Indeed, human pressure can be responsible for the depletion of vascular flora and the reduction in biomass production. Within the Campania region, some areas of the Vesuvius National Park are particularly exposed to the anthropogenic impact due to seasonal tourism. As a matter of fact, during spring and summer, a considerable amount of tourists pass through the Park areas, also with vehicles, thus causing the formation of dust clouds which are deposited over the vegetation close to the paths (Fig. 1). The main aim of this study is to analyse whether the deposition of dust on the leaf lamina of Centranthus ruber (L.) DC. subsp. ruber (Caprifoliaceae) plants can induce changes in leaf anatomy and in the efficiency of photosynthetic apparatus. The study was conducted on C. ruber plants growing at three sites, similar for environmental conditions and species composition. For each site two different sub-areas were considered: 1) the first, located along the side of the road, where a high deposition of dust (HD) was recorded on leaves, and 2) the second, placed at least five meters far from the path, where plants were subjected to a very low deposition of dust as control (LD). The amount of deposited dust was quantified at the study sites, in different periods of the year, characterized by different tourism access (spring-summer-autumn). Being C. ruber widespread throughout all the area of Vesuvius National park, it was chosen as an environmental indicator, making possible to evaluate the potential negative effects of the dust deposition on both anatomical and ecophysiological features. Functional traits in leaf lamina (e.g. stomatal size and frequency, percent of intercellular spaces in mesophyll) were quantified through light microscopy on fully-expanded leaves collected in summer (Fig. 2). Ecophysiological traits (chlorophyll a emission, photosynthetic pigment concentration and leaf traits) were carried out as well on fully expanded leaves, during spring and summer. Our results showed that HD leaves enhanced a pool of anatomical and photochemical traits allowing to overcome the effect of dust. Dust-induced changes in photosynthetic pigment content and stomata features were recorded. The overall analysis suggests that the greater amount of dust raised from the paths, shielded the leaf lamina: indeed leaves developing near the paths formed morphoanatomical traits as “shade leaves”. We infer that the phenomenon of dust deposition acts as a screen on leaves thus shading the photosynthetic apparatus from the light excess during summer. Although this phenomenon is positive for the optimization of C. ruber growth in these specific sites, the response of other species must be analysed to evaluate possible dust-induced vegetation dynamics consequent to possible species-specific adaptive capability.
978-88-85915-21-3
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/752426
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