VIE ET MILIEU - LIFE AND ENVIRONMENT, 2013, 63 (1): 59-65 EVIDENCE OF A LOCAL RANGE EXpansiON IN A FragmentatiON-SENSITIVE SPECIES: THE CASE OF RED SQUIRREL (SCIURUS VULGARIS) IN CENTRAL ItalY C. BATTISTI 1*, G. AMORI 2, F. M. ANGELICI 3, D. CAPIZZI4, S. DE FELICI 5, A. MORTELLITI 6, A. SCHIAVANO 7, P. VERUCCI 8, M. ZAPPAROLI 9 1 Ufficio Conservazione Natura, Servizio Ambiente, Provincia di Roma, Via Tiburtina 691, I-00159 Roma, Italy 2 Consiglio Nazionale delle Ricerche, Istituto per lo Studio degli Ecosistemi, Dipartimento Biologia e Biotecnologie “Charles Darwin”, Università degli Studi di Roma “Sapienza”, Viale dell’Università 32, I-00185 Roma, Italy 3 Via Cleonia 30. I-00152 Roma, Italy 4 Agenzia Regionale Parchi, settore Biodiversità, Geodiversità e Reti Ecologiche, Via del Pescaccio 96/98, I-00166 Roma, Italy 5 Dipartimento di Biologia, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica s.n.c., I-00133 Roma, Italy 6 Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università degli Studi di Roma “Sapienza”, Viale dell’Università 32, I-00185 Roma, Italy 7 Riserva Naturale Regionale Selva del Lamone, Corso V. Emanuele III 395, I-01010 Farnese, Viterbo, Italy 8 Riserva Naturale Regionale Monterano, Piazzale Tubingen 1, I-00060 Canale Monterano, Roma, Italy 9 Dipartimento per la Innovazione nei sistemi Biologici, Agroalimentari e Forestali, Università degli Studi della Tuscia, Via San Camillo De Lellis s.n.c., I-01100 Viterbo, Italy * Corresponding author: [email protected] SCIURU S VULGARI S ABSTRACT. – The Red squirrel Sciurus vulgaris Linnaeus, 1758 is currently expanding its CENTRAL ITALY range in plains and hills of Central Italy, colonizing or re-colonizing areas where it was never or FOREST HAB I TAT COLON I ZAT I ON only irregularly recorded since the 1950s. Here we report some observations regarding this EXT I NCT I ON range expansion based on a relatively large data-set covering the period 1850-2011 (471 records: WOODLAND MANAGEMENT 72 published, 399 unpublished) in a large study area covering the hills and plains of Tyrrhenian Central Italy (Latium). After considering the temporal patterns of a more recent sub-set of pres- ence data (1950-2009: i.e. six decades) we identified three geographic regions: (i) a large north- ern region with an area where the species occurred historically (at least since 1950: Volsini Mts) and an area where the species occurs more recently (after the1970s); (ii) a region with two areas, one where the species occurred irregularly between the 1970s and 2000s, and, a second one where it has occurred from the 2000s; (iii) a region where the species was locally extinct in the 1950s-1960s, where significant amounts of land reclamation and forest fragmentation and isola- tion occurred in the 20th century. These geographic and temporal patterns mirror (i) some recent changes in temporal and spatial regime of coppice management, (ii) abandonment of traditional farming and cultivation of mountainous areas, leading to an increase of forested area, (iii) imple- mentation of conservation measures in nature reserves and in Special Areas of Conservation (from the second half of 1970s), and (iv) the ageing of planted coniferous forests (mostly from 1950s). These co-occurring factors may explain the range expansion of the species in recent times. INTRODUCTION liti et al. 2009, 2010, 2011, Spinozzi et al. 2012). Recent studies performed in Central Italy have shown that an The Red squirrel Sciurus vulgaris Linnaeus, 1758 is a increase in forest habitat in the landscape increases the Palearctic forest rodent, relatively widespread in broad- probability of occurrence of the Red squirrel, while the leaved, mixed and coniferous forests of Europe from the role of structural connectivity (e.g., hedgerows) is less sea level up to the tree line (Gurnell & Wauters 1999). In important (Mortelliti et al. 2011). In addition this species Italy the species occurs in almost all mainland regions experiences high levels of mortality due to road accidents, except for most of the Po plain, the Adriatic coastal plains due to its high colonization ability (Gurnell 1991, Capizzi (due to historical anthropogenic forest fragmentation), & Santini 2007, Battisti et al. 2012). Nevertheless, when and a few southern regions (Campania, Basilicata and environmental constraints allow it (e.g., de-fragmenta- Calabria), while it is absent in Sicily, Sardinia and small tion among suitable patches, reduction of coppice man- islands (Wauters & Martinoli 2008). agement: Spinozzi et al. 2012), it may re-colonize areas S. vulgaris is sensitive to habitat loss and degradation (Santos-Reis & Mathias 1996, Bon et al. 2008). This phe- (Celada et al. 1994, Delin & Andrén 1999, Rodrìguez & nomenon has been highlighted in Italy and evidences of a Andrén 1999, Hale et al. 2001, Koprowski 2005, Mortel- recent range re-expansion after apparent historical extinc- 60 C. Battisti1, G. AMORI, F. M. ANGELICI ET AL. tions have been recorded in central regions such as south- have been arranged in a data-base and ordered geographically ern Tuscany and northern Latium (Contoli 1977, Contoli and chronologically, from North to South and from the oldest et al. 1980, Sforzi & Ragni 1997, Amori et al. 2007). to the most recent one, respectively. Data reliability has been We here provide new data on the local distribution of scored from 3 (max) to 1 (min), according to the authors evalua- this rodent in coastal and sub-coastal areas of the Tyrrhe- tion (expert based Delphi approach; Linstone & Turoff 1975). nian side of Central Italy. Following the observed spatial To assess the geographic similarity of the studied areas on and temporal patterns of occurrence (by original data or a historical basis we organized data using only the six most grey literature; e.g., Battisti et al. 2011), we hypothesize recent and complete 10-years periods (i.e., decades: from 1950 possible explanations of this range expansion. to 2009). This analysis allowed us to infer a pattern of similarity among regions on a historical basis, so facilitating an analysis on the hypothesized range expansion at this spatial scale. The METHODS similarity among geographic areas based on the presence of the species in the 10-years periods was calculated using the Cluster Study area: The area under investigation is part of the hilly method (Between Groups Linkage, Measure: squared Euclidean and plain sectors of the Tyrrhenian Central Italy that lies between Distance) using SPSS 13.0 for Windows software. the Fiora River (Northern border), and the Garigliano River (Southern border). The mid and lower stretch of Paglia, Tiber and Sacco rivers represent the eastern limits of the study district. RESULTS This area is about 20,000 km2 wide and includes parts of three administrative regions (from North to South: Tuscany, Umbria, Data set. Four-hundred-seventy-one records on the Latium), encompassing mountain and hilly reliefs of volcanic presence of S. vulgaris were collected from the study area origin (Tolfa, Cimini and Vicani Mts., Vulsini and Sabatini Mts., between the first half of the19th to the first decade of the Alban Hills) as well as coastal and sub-coastal plains (the south- 21th Century, 72 published (from near 50 bibliographic ern part of Maremma, Campagna Romana and Pontinia plain). sources) and 399 unpublished (389 data points from 2000 In our historical analysis we considered also bibliographic data to 2011, 10 in 1981–1999). Among published data, 34 referring to some anti- and sub-Apennine mountainous sectors (47.2 %) were given a score of 3 (maximum reliability; (Lepini, Ausoni, Aurunci Mts.). Geographic sectors analyzed see Methods), 37 (51.4 %) a score 2, 1 (1.4 %) a score 1 are reported in Fig. 1. For details on geology, orography, phy- (minimum reliability). Among unpublished records, 377 toclimatology and vegetation, see: Landi Vittorj (1989), Blasi (94.5 %) were given a score of 3 (maximum reliability), (1994), Blasi et al. (2010a, 2010b). 15 (3.7 %) a score 2, 7 (1.7 %) a score 1 (minimum reli- This study does not include the limestone groups of the west- ability). These data were used to rebuild historical and ern side of Central Apennines and the more internal Central present local range and dynamic of the species in the Apennines limestone western ranges (Sabini, Prenestini, Sim- study area. bruini, Ernici Mts.), corresponding to the historical known range Historical range. Historical range of this species in the of this species in peninsular Italy (Wauters & Martinoli 2008). Italian peninsula corresponds to a large part of Apennines and neighboring hilly contexts (Wauters & Martinoli Data collection and analyses: The local historic range of the 2008) and historical presence in Central Apennines is stat- species has been assessed from a critical review of bibliographic ed by several authors in the last decades (e.g., Angelici et data published between first half of the 19th Century and 2011. al. 1988, Sarrocco 1988, Various Authors 1989, Regione Records have been obtained from: i) historical literature (e.g., Lazio 1998; see review in Amori et al. 2009). For Cen- textbooks and papers in scientific periodicals published from the tral Italy, first scientific documents date back to the first first half of the 19thCentury to 1960); ii) modern scientific litera- half of the the 19th Century, when Bonaparte (1838-1841) ture (e.g., textbooks and papers published in peer reviewed jour- described the endemic subspecies S. v. italicus as pres- nals from 1960); iii) “grey literature” (e. g., non peer-reviewed ent in the Central Apennines but without providing exact literature, mostly published from 1970, inclusive of technical localities. reports and divulgative papers). The official mammal data-bank Some records have been published between the end of of the Province of Rome public Agency (Amori et al. 2009) has the 19th and the beginning of the 20th Century concerning been also included.