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In the context of XF-ACTORS project, a IoT based monitoring system has been established and tested in the field - for an olive grove in Puglia (Italy) affected by Xf - to measure in near real-time some parameters proxies of trees’ conditions and vulnerability under both abiotic (climate) and biotic factors. The system is based on the TreeTalker (TT) technology, comprising multiparametric sensors to monitor water transport in trees, trunk humidity and diametrical oscillations, spectral characteristics of the leaves and microclimatic parameters (temperature, relative humidity). In particular, the sap flow density can be retrieved according to the Heat Balance Method (Granier 1985) after measuring the temperature of two 20 mm long probes inserted into the stem wood at 10 cm distance along the trunk vertical axis; the probe in the higher position is heated while the lower one provides the reference temperature. The TT system collects and transmits data at hourly time frequency, thanks to a LoRa based wireless connection, to a node managed by another microcontroller (TT-Cloud) serving a few tens of devices in a cluster. The TT-Cloud is in turn connected to the internet via the GPRS network and sends data to a computer server. Here, raw data are subject to ETL procedure that allows data Extraction from the TT-Cloud source, data Transformation by cleaning and converting them into variables with eco-physiological meaning, and finally data Loading to insert them into the target spatio-temporal database, adopting proper storage format/structure for querying and analysis purpose. From here, data can be further elaborated and visualized, e.g. into useful statistics, through a tailored Data Science environment. The preliminary results on sap flow density are here presented as they can give important information about the impact of Xf that is known obstructing xylem vessels, reducing hydraulic conductivity and thus affecting evapotranspiration.

Mediterranean basin supports characteristic Mediterranean forests, woodlands, and scrub vegetation, highly adapted to the mild, rainy winters and hot, dry summers that characterize the Mediterranean climate. Never less the Mediterranean region has been identified as one of the hot spots of climate change. This study aims to understand what are the conditions of coexistence, thus biodiversity, of Mediterranean tree species in humid areas under future scenarios of altered hydrological regimes. The core of the work is a quantitative, dynamic model exploring the coexistence of different mediterranean tree species, typical of the arid or semi-arid wetland where ecological overlaps exist between mesic communities and those dominated by wetland specialists. The original idea of the paper is to address this topic from a deterministic approach using a dynamical model which is validated by existing data on species abundance. The dynamic of the population is broadly-defined according to the distinct adaptive strategies of trees for water stress of summer drought and winter flooding while climate change are explored as external forcing by means of a bifurcation analysis and compared with the major regional climate scenarios. I argue that at intermediate levels of water supply, which do not benefit either of the two species, the dual role of water (resource and stress) results in the coexistence of two kind of species, namely Hygrophilous and Non-hygrophilous. In order to support the validity of the ideas contained in the present study I applied the model to a Mediterranean coastal forested wetlands of Central Italy located into Castelporziano Estate and Circeo National Park. The results obtained show that there are distinct rainfall thresholds on the ability of Mediterranean wetlands to maintain species coexistence and hence to sustain biodiversity, calling for an urgent adaptation and mitigation response to prevent human pressure on water resources in proximity of wetland forested areas. Come è noto, il bacino del mediterraneo ospita una vegetazione fortemente adattata alle particolari condizioni climatiche che ne caratterizzano l’area. Inoltre la regione mediterranea è ricca di zone umide naturali ad elevata valenza ecologica. L’equilibrio di questi complessi sistemi naturali corre il rischio di essere alterato a causa dei cambiamenti climatici globali che, secondo i maggiori scenari climatici, mostrano un hot spot proprio nella regione mediterranea. Alla luce di questi fatti, la presente tesi mira ad individuare le condizioni climatiche per le quali la coesistenza, intesa quale sinonimo di biodiversità, di diverse specie arboree delle zone umide del mediterraneo è preservata. A tal fine è stato sviluppato un modello dinamico di competizione idrica per descrivere la coesistenza di due distinti gruppi di specie arboree (i.e. specie denominate igrofile e non-igrofile) che mostrano diverse strategie adattative allo stress idrico che caratterizza le zone umide del mediterraneo: drought estivo e flooding invernale. Al fine di verificarne la validità, il modello è stato validato sulle foreste umide planinziali della costa tirrenica integrando le informazioni rinvenute per i siti del Parco Nazionale del Circeo e della Tenuta Presidenziale di Castelporziano. I risultati ottenuti mostrano che per un regime idrico intermedio, rappresentato da quello attuale, in cui nessuna delle due specie è avvantaggiata, il duplice ruolo dell’acqua, risorsa-stress, garantisce la coesistenza delle due specie. Tuttavia, il trend con cui la precipitazione sta diminuendo è destinato a destabilizzare tale l’equilibrio nell’arco di qualche decennio, spostando il regime di vegetazione attuale da uno stato di coesistenza ad uno dominato dalle sole specie sclerofille. In generale, il modello è in grado di descrivere la dinamica delle popolazioni delle zone umide delle regioni aride o semi-aride in cui è facile rilevare sovrapposizioni ecologiche tra popolazioni relativamente più xeriche e quelle tipicamente più igrofile. Dottorato di ricerca in Ecologia forestale

In the context of XF-ACTORS project, a IoT based monitoring system has been established and tested in the field - for an olive grove in Puglia (Italy) affected by Xf - to measure in near real-time some parameters proxies of trees’ conditions and vulnerability under both abiotic (climate) and biotic factors. The system is based on the TreeTalker (TT) technology, comprising multiparametric sensors to monitor water transport in trees, trunk humidity and diametrical oscillations, spectral characteristics of the leaves and microclimatic parameters (temperature, relative humidity). In particular, the sap flow density can be retrieved according to the Heat Balance Method (Granier 1985) after measuring the temperature of two 20 mm long probes inserted into the stem wood at 10 cm distance along the trunk vertical axis; the probe in the higher position is heated while the lower one provides the reference temperature. The TT system collects and transmits data at hourly time frequency, thanks to a LoRa based wireless connection, to a node managed by another microcontroller (TT-Cloud) serving a few tens of devices in a cluster. The TT-Cloud is in turn connected to the internet via the GPRS network and sends data to a computer server. Here, raw data are subject to ETL procedure that allows data Extraction from the TT-Cloud source, data Transformation by cleaning and converting them into variables with eco-physiological meaning, and finally data Loading to insert them into the target spatio-temporal database, adopting proper storage format/structure for querying and analysis purpose. From here, data can be further elaborated and visualized, e.g. into useful statistics, through a tailored Data Science environment. The preliminary results on sap flow density are here presented as they can give important information about the impact of Xf that is known obstructing xylem vessels, reducing hydraulic conductivity and thus affecting evapotranspiration., IT; PPT; monia.santini@cmcc.it

Tropical deforestation is well known to have serious negative consequences for biodiversity, terrestrial carbon sinks and the balance of atmospheric greenhouse gases. By contrast, selective logging of tropical forests is often regarded as having a lesser impact on the ecosystem particularly in long terms, even though there have been few critical evaluations of the practice, particularly in Africa. We compared field data from 511 plots in the tropical forest of Sierra Leone, Ghana, Cameroon and Gabon. These plots were subject to different forest management practices: no recent logging (primary forests), selective logging (up to 30years old) and re-grown secondary forests post clear-cutting (at least 20years ago). Our findings suggest that the vertical structure and plant richness of the selectively logged and secondary forests change in different amplitude from those of primary forests, but stem density and the prevalence of vine and weed species differ greatly. We show that the effects of selective logging are greater than those expected simply from the removal of commercial species, and can persist for decades. Selective logging, unless it is practiced at very low harvest intensities, can significantly reduce the biomass of a tropical forest for many decades, seriously diminishing aboveground carbon storage capacity, and create opportunities for weeds and vines to spread and slow down the ecological succession.