Dottorato in BIOLOGIA AMBIENTALE ED EVOLUZIONISTICA

Titolo della tesi: “Valutazione dei servizi ecosistemici idrologici in aree rurali: analisi spazio-temporale in 4 comuni del territorio Pontino”

Ecosystem Services (ES) constitute a new socio-ecological approach to analyze the association between ecosystems, economical and social systems. More in detail, Hydrological Ecosystem Services (HES) are high-complexity systems because their regulation is modulated by soil quality, climate parameters, land morphology and human hydraulic intervention. The aim of this research is to analyze, model, and quantify provisioning and regulating HES at the local scale (municipality scale) in the Agro Pontino – Lazio region -, by monitoring both biophysical and socioeconomic trends. In particular, it is studied HES relating to water demand in agroecosystem, water balance and water supply (effective precipitation plus irrigation) included in CICES classification (CICES v.4.3, 2012), for Latina, Sabaudia, San Felice Circeo and Terracina Municipalities. More in detail, the aims of this study are to analyze the value of irrigated and non-irrigated agriculture in terms of savings, rational use and quantitative protection of water resources. The analysis of ES related to water consumption and the water balance for the agricultural sector is developed in space-time terms (1982-2010) analysis, to incorporate the impact of agricultural activities on water use in Agro Pontino plan. HES are also analyzed by means of scenario analysis in the medium-period (2027). The scenario analysis is developed according to Water Framework Directive (2000/60/EC) that suggested to examine the impact of water resources until 2027. Water is one of the most important HES for civil, industrial, agricultural, energy, aesthetic and recreational use, and aquatic life. For agroecosystems, ES related to water demand are important to realize the best crop production to either meet crop water needs or avoid water stress to the crop during drought periods. The quantity, quality, and timing of HES related to water demand are important factors in supporting human well-being, maintaining habitats for species, promoting and developing the capacity to use water resources in a more sustainable way. In agriculture, plant water demand is calculated by applying an evapotranspiration model (Thornthwaite method), considered as a potential requirement of plant. It is also analyzed water balance related to different type of crops: cereals, wheat, vegetables, forages, grapevine, olive, arboriculture and maize. It has been possible also to estimate irrigation and effective precipitation by water balance. Agricultural systems adopt mainly natural resources (such as soil, water, solar energy), and ES (e.g. cycle of nutrients, hydrological services, fertility of the active substrate, photosynthesis, pollination, biological pest control and many others) are among the main users of natural resources, as water. The knowledge of consumption’s time series, water needs related to species and drivers of changes - climate changes and change of use, land cover, policy and technologies -, are strategic to maximizing agricultural yields in terms of ES and sustainable development. Results show that the ecological and economic evaluation of water resources has given impacts related to changes of policy, technology, use, land cover and climatology. In Agro Pontino, arable land extension is decreasing overall, with the exception of vegetable and arboriculture cultivations. In terms of climate change, data show a moderate decrease in annual rainfall variability. For the period 1982–2010, we observe a significant decrease in plant water demand for crops and an increase for arboriculture. Economic evaluation of Ecosystem Services related to water consumption has been developed through the following approaches: the Benefits Transfer approach, the Value Market approach and Life Cycle Assessment approach. The results of Market approach showed a decrease of water for irrigation. The results from the relationship between plant water demand and the agroecosystem provide some suggestions for decision makers in Agro Pontino. In particular, they show that Agro Pontino arable land extension is decreasing overall, with the exception of vegetable and arboriculture cultivations. In terms of climate change, data show a moderate decrease in annual rainfall variability. Consequently, for the period 1982–2010, a significant decrease in plant water demand for crops and a consistent increase for arboriculture are observed. For HES, scenario analysis examined the effects of climate, land use and land cover changes in agroecosystems. Two scenarios were developed: normal scenario and worst case scenario. The results provide suggestions about adaptation and mitigation strategies, both for policy maker and stakeholder. In particular, worst case scenarios, due to increasing of temperatures and reducing of precipitations and land use, confirms that it will leads to a decreasing of runoff. The decrease of runoff causes an increase of water stress and soil degradation and, consequently, a loss in terms of agricultural production value for Agro Pontino economy. Scenarios analysis allows to understand the needs of agricultural economy of the Agro Pontino plan for Latina, Sabaudia, San Felice Circeo and Terracina Municipalities.