*Manuscript 1 On the use of Spatial Ecological Modelling as a tool for improving the 2 assessment of geographic range size of threatened species 3 4 SEM and Species geographic range size 5 6 Fabio Attorre a, *, Michele De Sanctis a, Alessio Farcomeni b, Alfredo Guillet c, Edoardo Scepi a, 7 Marcello Vitale a, Francesca Pella d, Mauro Fasola d a 8 Dipartimento di Biologia Ambientale, Sapienza Università di Roma, P. le A. Moro 5 - 00185, Roma, Italy 9 bDipartimento di Salute Pubblica e Malattie Infettive, Sapienza Università di Roma, P. le A. Moro 5 - 00185, Roma, 10 Italy 11 cUnità Tecnica, DGCS, Ministero Italiano degli Affari Esteri, Via S. Contarini 25, 00194 Roma, Italy 12 d Dipartimento Scienze Terra Ambiente, Università degli Studi di Pavia, Via Ferrata 9, 27100 Pavia, Italy 13 14 *Correspondence: Fabio Attorre, 15 Environmental Biology Department 16 Sapienza University of Rome, Italy 17 E-mail:
[email protected] 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 1 1 Abstract 2 We analysed endemic threatened tree and reptile species of Socotra Island (Yemen), characterised 3 by different ecological requirements and spatial distribution, in order to evaluate the usefulness of 4 spatial ecological modelling in the estimation of species extent of occurrence (EOO) and area of 5 occupancy (AOO). Point occurrences for the entire species range were used to model their spatial 6 distribution by Random Forest (RF) and Generalised Linear Model (GLM). For each species the 7 suitability area (SA) was obtained by applying the 0% omission error criterion on the probability 8 map, and compared or integrated with EOO and AOO area obtained by topological methods such as 9 the minimum convex polygon (MCP), α -hull and 2x2 km grid.