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Avocetta 30: 5-14 (2006)

Biological significance and conservation of biogeographical populations as shown by selected Mediterranean species

BRUNO MASSA

Stazione Inanellamento, c/o Dipartimento SENFIMIZO dell’Università di Palermo, v.le delle Scienze 13, I-90128 Palermo, Italy ([email protected])

Abstract – From the conservation point of view there is an important difference between species that are treated as whole and species considered as separate subspecies; these represent important components of biodiversity and deserve conservation for their potential evo- lution and their characteristics. EU Bird Directive shows an attempt to protect subspecific taxa, when really necessary for conservation purposes. There are some examples of species regarded as secure, if considered as whole, that turn out to be endangered or critically endangered when treated as subspecies (e.g. Mediterranean storm petrel, lanner falcon, rock partridge, Andalusian hemipode, long-tai- led tit and crossbill). Status of some species should have to be modified, basing information on more objective comparison with those available for related species (e.g. the pairs Manx and Yelkouan shearwaters, European and spotless , and North African blue tit). Moreover, some species have a very restricted distribution, that might be considered an endemic bird area, holding two or more species with a range covering less than 50,000 km2 (e.g.: Marmora’s warbler, Cyprus warbler, Cyprus wheatear and Corsican citril ). Here I suggest to reconsider, among future conservation priorities, the status of a number of S European species in the light of previous con- siderations, avoiding some paradoxes, such as incongruity of risk level, when compared to other bird species.

Riassunto – Significato biologico e conservazione di popolazioni biogeografiche di alcune specie dell’avifauna mediterranea. In tema di conservazione della natura, c’è una sostanziale differenza se una specie è trattata nel suo complesso o si prendono in considerazione separatamente le sue sottospecie; queste ultime rappresentano componenti molto importanti della biodiversità e meritano un’adeguata conservazione per l’intrinseco potenziale evolutivo e le loro caratteristiche uniche. L’Allegato I della Direttiva Uccelli (409/79 e 244/91) è indubbiamente un fondamentale tentativo a livello europeo di tutelare taxa sottospecifici, nei casi in cui per essi si ritengono necessarie azioni di conservazione. Tuttavia, queste indicazioni non sono state seguite in importanti occasioni; ci sono numerosi esempi di specie definite “sicure” se considerate nel loro complesso, ma che risultano “minacciate” o “minacciate in modo critico” se trattate a livello sot- tospecifico (esempi sono l’uccello delle tempeste mediterraneo, il lanario, la coturnice, la quaglia tridattila, il codibugnolo ed il crociere). Lo status di alcune specie dovrebbe essere corretto, sulla base di informazioni più obiettivamente confrontate con quelle disponibili di specie affini (ad esempio le coppie berta minore atlantica/berta minore mediterranea, storno/storno nero e la cinciarella algerina). Inoltre, esistono specie con una distribuzione molto circoscritta, che andrebbe correttamente considerata come un’area avifaunistica endemica, cioè ospitante due o più specie con un areale inferiore ai 50.000 km2 (esempi sono la magnanina sarda, la silvia di Cipro, la monachella di Cipro ed il venturone corso). Alla luce delle considerazioni fatte, si propone, tra le priorità conservazionistiche dell’immediato futuro, di riconsiderare lo status di molte specie europee, evitando in tal modo alcuni paradossi, quale l’incongruità del livello di rischio per molte specie d’uccelli, se paragonata ad altre.

Biodiversity is the total variety of life on Earth, centages of declining species clearly represent an including all genes, species and ecosystems and the important information, but it is necessary to avoid ecological processes of which they are part (Wilson ambiguity in preserving species and habitats. Many 1988, Mc Neely et al. 1990); maintaining it means European researchers gathered their efforts in a preserving species on the whole, and their isolated foundamental work, largely based on IUCN (2004) subspecies as well. Conservation is a science which criteria, that concerns the new update of status and clearly needs to dialogue with bureaucracy and pol- trend of European bird populations (BirdLife Inter- itics. Investigations on species’ status and list per- national 2004). Novelty generally brings both oppor- tunities and risks. Since this update represents a sci- Received 10 April 2006, accepted 26 September 2006 entific source, the main opportunity is that its con- Assistant editor: D. Rubolini tents are likely to be used as the main reference for

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the update of Annex I of Bird Directive 409/79. reach the reproductive isolation in many populations. However, information sources on population esti- Sometimes results of molecular genetics contradict mates and trends provided by different countries are previous ideas about species integrity or taxonomic heterogeneous and have a variable quality; this distinctions based on phenotypic descriptions; an entailed some subjective choices in the inclusion of interesting example is the pair F. peregrinus/F. pele- species within the different categories. Some threat- grinoides (Wink and Sauer-Gürth 1998) treated as ened species could run the risk not to obtain the nec- separated species by some authors; nevertheless, essary attention at European level. The aim of even if recent molecular researches (Seibold et al. BirdLife International (2004) is the identification of 1993, Wink and Seibold 1996) concluded that pele- priority species so that conservation actions can be grinoides is a valid species, very close to peregrinus, taken to improve their status; therefore the exclusion Wink et al. (1998), using mtDNA cytochrome b of some species/subspecies from its official list sequence, found a very high affinity between pere- would mean also their exclusion from conservation grinus and pelegrinoides with a genetic distance processes. Of course I agree with the IUCN (2004) below 0.6% (distance at specific level in Falconidae criteria for the red list compilation, but I believe that family should be over 1.5%), proposing to continue the right moment has come to schedule, among to treat them as conspecific. Another interesting future priorities for bird conservation, the inclusion example concerns the sparrows; Hagemeijer and of some biogeographical populations which are the Blair (1997) list the Italian sparrow (Passer italiae) result of an evolutionary process in progress. EU as a stabilized hybrid, while the authors of BirdLife Bird Directive (709/79 and 244/91, Appendix I) International (2004) neglect it and misunderstand shows an attempt to consider subspecific taxa, when that the very small figure of 50-100,000 pairs of really necessary for conservation purposes (e.g.: Passer domesticus (living only on the Alps) is the Phalacrocorax aristotelis desmarestii, Lagopus total Italian amount (thus excluding the much larger muta helvetica, Alectoris graeca whitakeri, Alectoris “italiae” population). If the subspecies level should graeca saxatilis, Perdix perdix italica, Perdix perdix get an appropriate acknowledgement, it could enter hispaniensis, etc.). These should be preserved for into official lists, when conservation status of these their potential evolution and acquisition of unique “subgroups” requires particular attention. The conti- characteristics, which represent important compo- nuity of the evolutionary process through space and nents of biological diversity; if effectively isolated, time means that decisions on the limits of species and they may become new species by acquiring genetic their distributional boundaries are, to some extent, isolating mechanisms. Bird subspecies are allopatric arbitrary, but the way in which species are defined subpopulations, generally maintained by spatial seg- and delineated can influence our perception of distri- regation, that share i) a unique geographic range or bution patterns and diversity (Newton 2003). Assum- habitat, ii) a group of phylogenetically concordant ing that a decision to treat a taxon at species or sub- array of phenotypic and genetic characters, iii) a species level may depend on the scientist subjectivi- unique natural history relative to other subdivisions ty, on the species concept applied (Rojas 1992, de of the species, (still) genetically compatible with Queiroz 1998, Fraser and Bernatchez 2001, Helbig et other subpopulations (O’Brien and Mayr 1991, al. 2002) or on methodology used (Pasquet and Amadon and Short 1992). Thibault 1997, Haring et al. 1999, Sangster 2000, Each of the geographical forms classed as sub- Sangster et al. 2005), a careful use of subspecies lev- species occupies particular areas which, all together, el in global approaches may result more useful and give the range of the species as a whole. If these geo- suitable for bird conservation. graphical forms were classed as allospecies (popula- Conservation biologists tried to search for meth- tions derived from the same common ancestor whose ods distinguishing unambiguous units for conserva- ranges differ and do not touch), we would have sev- tion purposes, and employed evolutionarily signifi- eral smaller ranges in place of a large one (Newton cant units (ESU) as basic units of analysis, when evi- 2003). From the conservation point of view there is dence clearly indicated that a formally recognized an important difference to treat a species as whole or species either fails to convey important evolutionary its subspecies separately. Taxa that are apparently and geographical information or fails in delineating well differentiated, possibly young or having fre- a natural entity (Riddle and Hafner 1999). “ESU” quent gene flow with other subspecies, still do not was coined by Ryder (1986) as “a subset of the more

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inclusive entity species, which possess genetic International 2004). Others show a scattered distribu- attributes significant for the present and the future tion clearly divided according to subpopulations, generations of the species in question”; interestingly, characterized by biological, morphological and genet- ESU had both important and biological employ ic traits that allow to consider them independently. under the USA Endangered Species Act, the Aus- Habitat loss and fragmentation is considered by far tralian Environment Protection and Biodiversity the most pervasive threat, impacting 86% of endan- Conservation and the Canadian Species at Risk Act. gered ; over-exploitation and invasive alien Entities defined as ESU arise from the accumulation species are also impacting about 30% of threatened of genetic differences through the various roles of birds (the latter 67% on islands) (Baillie et al. 2004); evolutionary forces through the time. However, in addition, an evident difference exists between bio- along the years ESU concept varied very much in logical cycles of migrant and sedentary birds, since accordance with different criteria (e.g. Fraser and the density of the first is consistently influenced by Bernatchez (2001) report eight different definitions); conditions in different parts of the world. Small areas, the lack of agreement about the concept of the ESU such as Mediterranean islands, host many endemic origins from the same philosophical and interpreta- taxa, among birds too; even if threatening processes tive dilemmas that plague the scientific definition of vary both within and between taxonomic groups, species (Kelt and Brown 2000, Green 2005). Conse- threats to terrestrial and marine birds in these fragile quently, as well as the species concept, no definitive ecological systems need conservation interventions to concept of ESU prevailed so far. Moreover, Crandall ensure their continued survival. et al. (2000) proposed that ESU concepts might be Hereby I report some examples of biogeographi- replaced by a more holistic concept of species, con- cal populations that should benefit of a stricter con- sisting of populations with varying levels of gene servation approach. flow evolving through drift and selection. Finally, Green (2005) proposed the use of the Designatable Units (DU), methodology adopted by the Committee BIOGEOGRAPHICAL RELEVANCE OF PRE- on the status of Endangered Wildlife in Canada; SERVING SUBSPECIES determining DUs constitutes a two-part test and asks, in the first place, if putative DUs are distin- Cory’s shearwater Calonectris diomedea guishable and, then, if they have different conserva- tion status; DUs may also be identified on the basis Assuming that C. edwardsii is a valid species of demonstrations of genetic distinctiveness, similar (Hazevoet 1995), currently at least three large popu- to those used for the recognition of the ESU (Green lations of C. diomedea are known, belonging to two 2005). Species ranges are genetically, demographi- subspecies, namely C. d. borealis (Atlantic islands, cally, spatially, and ecologically so heterogeneous wintering in S America) and C. d. diomedea, with that current cannot always capture whole two populations, that differ biometrically (Massa and relationships, but measures to prevent the reduction Lo Valvo 1986) and in their vocalizations (Bretag- or the loss of the species should not be postponed for nolle and Lequette 1990), one in the central-western a lack of full scientific certainty. Overall, consider- Mediterranean, wintering in S Africa, and the other in ing species as dynamic evolutionary units is less the eastern Mediterranean. According to Randi et al. affected by the species problem and more related to (1989) and Wink et al. (1993) genetic differences conservation science (Rojas 1992). between birds in Mediterranean and Atlantic colonies In the last 10-20 years some species have under- are of the same order generally found between sub- gone numerical and distributional range increases species, showing a moderate gene flow in Mediter- (e.g.: Columba palumbus, Turdus merula, Sylvia atri- ranean and Atlantic C. diomedea. The high nest site capilla, Sylvia melanocephala, Regulus ignicapilla, fidelity (Jouanin et al. 1977, Massa and Lo Valvo Certhia brachydactyla, Fringilla coelebs, 1986, Ristow et al. 1990, Thibault 1993, 1994, chloris, Emberiza cirlus, etc.); thus, because of their Swatschek et al. 1994) minimizes the immigration well documented and justified secure status, it seems contribution of external individuals to the dynamics reasonable to transfer them from the category of of each colony (but cf. Lo Valvo and Massa (1988) species with favourable conservation status, but con- and Thibault and Bretagnolle (1998), who record centrated in , to “secure” category (BirdLife interesting evidence of gene flow between the two

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subspecies). Different populations of Atlantic and et al. 2004). In total, Mediterranean basin hosts Mediterranean Calonectris diomedea differ in mtD- 8,500-15,200 pairs of melitensis, a very small pro- NA cytochrome b sequence as much as 1.51-1.87 %; portion of the whole European population, estimated it should be reminded the fact that between taxa between 430,000 and 510,000 pairs (BirdLife Inter- recently raised to species level, Larus cachinnans, L. national 2004). A major factor limiting the breeding fuscus and L. argentatus, mtDNA cytochrome b distribution of this species is the presence of safe divergence is 0.69-2.04 % (Helbig 1994). According colony sites on islands, that is why the Mediterranean to BirdLife International (2004) the populations of C. populations are so depleted. Tucker and Heath (1994) diomedea amount to 270-290,000 pairs, have a vul- considered the species as localized (= with popula- nerable status and are in decline. As other shearwa- tions highly concentrated in few sites), while ters, they show strong philopatry, with the majority of BirdLife International (2004) changed the status to young returning to the colony where they hatched, secure, thanks to improved knowledge of the Atlantic and a very small demographic growth (e.g.: Ristow et distribution and numbers, which show a stable trend. al. 1990). It is evident that all three biogeographical From the conservation point of view, it should be a populations need to be preserved. Additionally, some prerequisite condition to treat melitensis separately, populations undergo an anachronistic and illegal maintaining it in the SPEC2 category; Mediterranean over-exploitation of eggs and more recently the rat populations, indeed, are declining and critically predation; for instance, people of Linosa Is. (Sicilian threatened in their breeding sites, due to human Channel, Italy) every year collect approximately 2- impact and rat predation (Massa and Sultana 1991). 3,000 eggs from a population of about 10,000 pairs, and in the last years rats are a further reason of their low breeding success. BirdLife International (2004) Lanner falcon Falco biarmicus includes the species among the SPEC2 category (with unfavourable conservation status, concentrated Its global European population is estimated as much in Europe). In this case, even separating the three bio- as 480-900 pairs, the majority of which lives in geographical populations cited above, they would Turkey and Italy. If we consider the species as remain in the SPEC2 category. whole, Europe holds a tiny proportion of the global range. As regards its subspecific status, it is clearly differentiated in morphologically distinguishable European and Mediterranean storm petrel Hydro- isolated populations, breeding in S Europe and small bates pelagicus part of Middle East (Falco b. feldeggii), in N Africa (F. b. erlangeri), and in Africa, S of Sahara (F. b. As the other petrels, this is a k-selected species, biarmicus). In Europe the species is considered showing a very high breeding site fidelity (Amengual SPEC3, vulnerable (BirdLife International 2004); et al. 1999, Lo Valvo and Massa 2000). Extinction for conservation purposes, it should be more consis- probability should be higher for species with low tent to consider these sedentary biogeographical intrinsic rates of increase, compared to r-selected populations, among which apparently there is no species, when population is small (Pimm et al. 1988). gene flow, as separated taxa and to include the “rare” Additionally, two biometrically and genetically dis- European subspecies within the SPEC2 category. tinct subspecies have been recorded, one (H. p. pelagicus) in the Atlantic, and the other (H. p. melitensis) in the Mediterranean, the latter character- Rock partridge Alectoris graeca ized by a larger size and some different reproductive parameters (Hemery and D’Elbée 1985, Catalisano et It is one of three Mediterranean endemic species of al. 1988, Bretagnolle 1992, Lo Valvo and Massa the Alectoris; endemic to Alps, Apennines, 2000, Lalanne et al. 2001). Divergence between Balkans and Sicily, it has undergone a continuing pelagicus and melitensis possibly resulted from pale- decline over the last decades, mainly due to hunting. ogeographic changes in the Strait of Gibraltar, mak- Listed as SPEC2 by Tucker and Heath (1994) and ing isolation of the Mediterranean population possi- BirdLife International (2004), it is subdivided into ble. The latter, indeed, shows a very low genetic dif- populations, fairly distinguishable and described as ferentiation, unlike the Atlantic population (Cagnon distinct subspecies. Genetic data partially support

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subspecies subdivisions, and allow to delimite distinct considered secure in the NonSPECE category (Bird- conservation units. According to Lucchini and Randi Life International 2004). However, there are some (1998) and Randi et al. (2003), populations from geographically isolated populations, whose subspe- Apennines and Balkans were probably connected by cific status is clearly recognized (e.g. A. c. siculus in gene flow since the last glacial maximum, through a Sicily); their sedentary habits and probable absence late Pleistocene Adriatic landbridge, while estimates of gene flow with other populations should bring of divergence times suggested that Sicilian rock par- conservation scientists to treat them separately. tridges were isolated for more than 200,000 years. Deglaciated Alps were probably colonized by two dis- tinct source populations, bringing about differences European and Mediterranean crossbills Loxia observed between eastern and western populations. curvirostra Rock partridges in Sicily, formally recognized as A. g. whitakeri, met the criteria for a distinct evolutionary Variability in the cone crop of coniferous trees is significant unit; Randi et al. (2003) identified two thought to be the most important cause of the major mtDNA phylogroups, splitting partridges from nomadic nature of this species; nevertheless, noma- Sicily vs. all the other sampled populations at an aver- dism did not prevent the isolation of geographical age genetic distance of 0.035, corresponding to 65% forms. This species is a very interesting example of of the average distance between closely related evolutionary process in progress. Crossbills with a species of Alectoris. Interestingly, bottleneck and mis- slender bill feed on several species, whereas match analyses indicate that rock partridges lost vari- those with a strong bill feed only on , which ability through past population declines, and did not have cones larger than other . Correlation expand recently. Assuming the uniqueness of this tax- between cone scales length and the index of bill cur- on, very declining and critically endangered in the vature supports the hypothesis that bill size is an few Sicilian sites where scanty populations still sur- adaptive character for feeding on cones (Lavau- vive, on an area certainly smaller than 5,000 km2, it den 1924, Massa 1987, Knox 1990, Clouet 2003). should be more consistent to treat this subspecies sep- Fossils prove that L. curvirostra was definitely pres- arately from the others, listing it within the SPEC1 ent in S Europe and the Near East at least from the category (species of global conservation concern). middle Würmian onwards and probably throughout Noteworthy is that the Bird Directive lists A. g. the Würmian, and that larger birds (L. pytyopsittacus whitakeri and A. g. saxatilis in the Annex I. size) existed at least in a limited area of the W Alps from the glacial maximum onwards; S European crossbills were isolated from their Siberian con- Andalusian hemipode Turnix sylvaticus geners during the early and middle Würmian (Tyr- berg 1991). Large-billed crossbills on Mediterranean Almost certainly it has become extinct in Europe, islands and N Africa are probably descendants of and it is on verge of extinction in N Africa. Violani Pleistocene populations living on dominant conifers. and Massa (1993) found remarkable biometrical dif- They must have fed mainly on pine cones, since oth- ferences between the Mediterranean form (T. s. syl- er conifers were absent or rare W of Urals. A cen- vaticus) and sub-Saharan and asiatic ones, conclud- trifugal spread from central European populations ing that its extinction does mean the disappearance northwards and southwards may have produced of a Mediterranean endemism for ever; following large-billed forms (Eck 1981), such as L. scotica, L. them, Mediterranean subspecies should be included pytyopsittacus and Mediterranean populations; feed- in the SPEC1 category, not SPEC3, as BirdLife ing on pines and evolving relatively long tongues International (2004) did. which increased probing ability (Benkman 1987) on exploiting conifers regularly fruiting for extended periods, they acquired the potential to become seden- Long-tailed tit Aegithalos caudatus tary (Massa 1987, Senar et al. 1993, Clouet and Joachim 1996, Clouet 2003). From analysis of mtD- Widespread and common species everywhere in NA, species formation in birds is estimated to take Europe, where global populations cover less than half around 2.5 million years, varying between 0.2 and of its global distribution. Consequently its status is 5.5 million years, while subspeciation is estimated to

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take a short time, sometimes less than 10,000 years no new nesting colony has been recorded (different- (Newton 2003); it is not certain that an isolation peri- ly from P. puffinus, which has established since 1977 od of c. 10,000 years is sufficient for speciation to on a N American island off Newfoundland, far from take place. The three taxa of Crossbills (Loxia curvi- any other known colony: Storey and Lien 1985). rostra, L. scotica and L. pytyopsittacus) show no con- From the conservation point of view, the place of P. sistent differences in either mithocondrial DNA or yelkouan should have been more correctly within nuclear microsatellite sequences, and substantial SPEC2, with vulnerable status. overlap in the main morphological character (bill depth) that supposedly separates them (Piertney et al. 2001). They occur as different ecotypes, differing in European starling vulgaris and spotless body size, call notes, bill size, colours and food pref- starling Sturnus unicolor erences. Selective pressures were sufficiently strong to trigger and enhance morphological evolution and The first is a widespread breeder across most of rapid local adaptation to resources, without necessar- Europe, where less than half of its global population ily promoting the development of reproductive barri- lives; it has been introduced in S Africa (1897), Aus- ers between morphs (Questiau et al. 1999). Follow- tralasia (1856-1881) and N America (1844-1890), ing Groth (1993), N American crossbills belong to where currently it has a population of one hundred eight sibling species, where mated pairs contain millions of individuals and is considered as an agri- members of the same morphotype in areas where dif- cultural pest and vector of parasites and diseases ferent forms are sympatric. European crossbills pos- (Lever 2005). According to Feare (1989) a down- sibly belong to different species as well, even if it is ward trend has occurred in N European populations, currently not clear how these forms avoid interbreed- probably not due to usual fluctuations; in recent ing in the wild (see Knox 1990 for L. scotica). times the global population was estimated as much as Mediterranean populations consist of small flocks, more than 23,000,000 pairs, and underwent a moder- generally of tens, rarely of hundreds, so local, seden- ate decline (>10%) in the northern countries, bal- tary and strictly linked to pine forests that may be anced by an increase in the southern ones (Feare considered as endemic taxa; consequently, their sta- 1989, BirdLife International 2004). The second tus is never secure and deserves a particular attention. species is endemic to western Mediterranean; Euro- pean populations represent >50% of global range. Despite its limited distribution, European global pop- ADJUSTMENT OF THE STATUS OF SOME ulation (> 2,100,000 pairs) has recently increased. S. SPECIES vulgaris was transferred from NonSPEC to SPEC3, while S. unicolor status remained the same (Non- Yelkouan shearwater Puffinus yelkouan SPECE = SPEC4) (Tucker and Heath 1994, BirdLife International 2004). This is contradictory; the criteri- Assuming that P. mauretanicus is a separate species on used was mainly the recent trend, but the differ- (Heidrich et al. 2000), Europe holds 13-33,000 pairs ence of natural history, population amount and range on a geographic range of about 100,000 km2 (almost distributions do not justify the discrepancy. exclusively on islands), representing more than 95% of the whole population. Although data about trends during 1990-2000 were not available for certain North African blue tit Parus teneriffae countries (4 out of 9, that is 45%) and only four countries considered this species stable, Tucker and Following Salzburger et al. (2002), Canary and N Heath (1994) and BirdLife International (2004) African populations belong to a distinct species from record it as stable and with secure status (respective- P. caeruleus. Europe holds a small population of the ly including it in SPEC4 and NonSPECE categories, subspecies ultramarinus on the isle of Pantelleria that is with favourable conservation status, but con- (Sicilian Channel, Italy); it shows a very low produc- centrated in Europe). However, the whole popula- tivity (Lo Valvo and Massa 1995), possibly balanced tion of this species is very small and scattered on by a limited winter mortality. According to criteria of islets (differently from the SPEC2 P. puffinus and C. BirdLife International (2004) P. caeruleus is a Non- diomedea, large colonies are rare in P. yelkouan) and SPECE; they do not treat P. teneriffae, but the unfa-

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vorable status of this species not concentrated in allospecies, S. balearica, endemic to Balearics, and Europe should bring to the SPEC3 decision for it. S. sarda, living in Corsica, , Tuscany Is. and Pantelleria Is. It is considered as secure, its overall trend is unknown, and the whole population estimate ENDEMIC BIRD AREAS is very low (56-110,000 pairs, according to Tucker and Heath 1994, 29-75,000 pairs according to It is known that of the 127 bird species that became BirdLife International 2004); as the small population extinct in the last 400 years, 116 (91 %) were island of Pantelleria probably became extinct, the species is species, which, therefore, disappeared at a rate 40 eventually in decline. However, it is contradictory times faster than continental ones (Newton 2003). All that this local species falls within NonSPECE cate- the taxa restricted only to some archipelagoes (e.g.: gory, while the Dartford Warbler S. undata, with Canary Is., Sardinia-Corsica, Balearic Is., Cyprus, 1,900,000-3,700,00 pairs widespread over more than etc.) should be recorded within a separate list, 1,000,000 km2, even if depleted and subjected to demanding attention at the highest level. Some birds, large historical decline, lies in the SPEC2. indeed, cover a distribution that may be considered as Endemic Bird Area (EBA), holding two or more restricted range species (= with a range covering less Cyprus warbler Sylvia melanothorax than 50,000 km2) (Long et al. 1996). Stattersfield et al. (1998) already included Cyprus among EBA of the Endemic only to Cyprus, formerly listed as SPEC2 world, giving to it a high priority; moreover, they list- (Tucker and Heath 1994), its global population, thanks ed Corsican mountains among secondary EBA (fewer to a better estimate of previous figures, now amounts than two species are entirely confined to it), pointing to 70-140,000 pairs (BirdLife International 2004). out that if citrinella corsicanus was recog- nized as a separate species, Corsica, Sardinia, Elba and off-lying islands would be qualified as an EBA. Cyprus wheatear Oenanthe cypriaca Afterwards, Sangster (2000), giving to Serinus corsi- canus the species rank, proposed to include Corsica Endemic to Cyprus, previously listed as SPEC2 among EBA. Actually, Sardinia, Corsica and Tuscany (Tucker and Heath 1994), its global population, Is., amounting to less than 35,000 km2, could be qual- according to a new by far larger estimate (90- ified as an EBA; nevertheless, following the Impor- 180,000 pairs: BirdLife International 2004), now is tant Bird Areas global criteria (A level, category 2) considered out of danger. As the previous species, it (Fishpool and Evans 2001), Balearic Islands, Sar- inhabits an EBA, covering less than 8,000 km2 (Stat- dinia, Corsica and Tuscany archipelago, amounting to tersfield et al. 1998). less than 50,000 km2 area, could be qualified as an EBA, since they host the following taxa that have a range covering less than 50,000 km2: Puffinus maure- Citril finch Serinus [citrinella] corsicanus tanicus (Balearic Is.), Sylvia sarda (including baleari- ca) (Balearic Is, Corsica, Sardinia, with a possible Barbagli and Violani (1997) pointed out that the extension to Pantelleria Is.), Sitta whiteheadi (Corsi- adjective corsicanus should be adopted as the cor- ca), Serinus corsicanus (Sardinia, Corsica and Tus- rect name instead of corsicana, agreeing in gender cany archipelago). Thus, the following species listed with the generic name Serinus (masculine) and not as NonSPECE category (BirdLife International 2004) with the specific name citrinella, a feminine noun show a concentration that should be used as a prereq- placed in apposition. Pasquet and Thibault (1997) uisite to include them in the SPEC2 category. considered distinctive ecology, vocalizations, plumage pattern, measurements and genetic differ- ences between corsicanus and citrinella within the Marmora’s warbler Sylvia sarda limit of subspecies/species; however, Sangster (2000) reinterpreted their findings and considering It may be considered as an endemic taxon, very con- that there are strong evidences that both taxa have centrated in few islands. According to Shirihai et al. unique evolutionary histories proposed corsicanus (2001) it is a superspecies comprising two insular as a valid species. The small and probably stable

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population of corsicanus (<85,000 pairs) (BirdLife Boano, Pierandrea Brichetti, Lorenzo Fornasari, Fulvio International 2004) is restricted only to Sardinia, Fraticelli, Paolo Galeotti, Francesco Mezzavilla, Diego Corsica and Tuscany islands. Rubolini, Fernando Spina, Guido Tellini and Carlo Violani) who commented constructively the manuscript, sharing opinions here expressed; I also thank Toni Min- gozzi and Nicola Baccetti who suggested fruitful com- CONCLUSIONS ments on the first draft. Valentina Lo Verde and Daniela Castellano improved the language. The list of bird species discussed above cannot be con- sidered comprehensive. It emphasizes some emblem- atical examples, which allow highlighting the root REFERENCES question requiring an imperative answer to achieve a rational conservation strategy. It should take into Alström P, Mild K 2004. ‘Biological’, ‘phylogenetic’ and account species not only as systematic entities, but ‘monophyletic’ species – same or different? Alula 10: also as biological ones, evolving and possibly com- 96-103. posed by isolated populations, genetically shaped by Amadon D, Short LL 1992. Taxonomy of lower cate- drift and selection. Other subspecies or evolutionary gories. Suggested guidelines. Pp. 11-38 in: Monk JF significant entities would deserve more attention (e.g.: (ed.), Avian Systematics and Taxonomy. Bulletin of Accipiter nisus wolterstorffi, Accipiter gentilis arrigo- the British Ornithologists’ Club, centenary Vol. 112A. Amengual JF, Gargallo G, Suarez M, Bonnin J, Gonzalez nii from Corsica and Sardinia, Parus palustris siculus JM, Rebassa M, McMinn M, 1999. The Mediterranean from Sicily); recognition both of species and popula- Storm Petrel Hydrobates pelagicus melitensis at Cabr- tions below the species level for assessment must be era archipelago (Balearic Islands, Spain): breeding, guided by the general objective of preventing elements moult, biometry and evaluation of the population size of biodiversity from becoming extinct. The main con- by mark and recapture techniques. Ringing & Migra- servation aim should be to preserve both evolutionary tion 19: 181-190. processes and ecological viability of populations by Baillie JEM, Hilton-Taylor C, Stuart SN (eds) 2004. 2004 maintaining all the genetic populations within the IUCN Red List of threatened Species. A global Species Assessment. IUCN, Gland and Cambridge. 191 pp. species so that the process of evolution would not be Barbagli F, Violani C 1997. Canaries in Tuscany. Bolletti- excessively compelled. If there is substantial concern no del Museo regionale di Scienze naturali di Torino that an isolated population of a species is on verge of 15: 25-33. extinction, this information should be used to achieve Benkman CW 1987. Crossbill foraging behavior, bill an official status enabling formal protection; follow- structure, and patterns of food profitability. Wilson ing Alström and Mild (2004), the main advantage of Bulletin 99: 351-368. classifying all least-inclusive taxa (giving primacy to BirdLife International 2004. Birds in Europe. Population evolutionary history) as species is that they receive estimates, trends and conservation status. BirdLife more attention, which can be crucial for endangered International Ser. No. 12, Cambridge, UK (compilers: Burfield I and van Bommel F). taxa. The acknowledgement of conservation status for Bretagnolle , 1992. Variation géographique des vocalisa- isolated populations at risk of extinction is an action tions de Pétrels ouest-paléarctiques et suggestions tax- taken in the process of using science in support of pol- onomiques. Alauda 60: 251-252. icy. Policy on endangered species conservation is Bretagnolle V, Lequette B 1990. Structural variation in the based on designation of extinction risk status for rec- call of the Cory’s Shearwater (Calonectris diomedea, ognizably distinct biological entities; what is required Aves, Procellariidae). Ethology 85: 313-323. are biological units that may be designated on the Cagnon C, Lauga B, Hémery G, Mouchès C 2004. Phylo- basis of their conservation status, not necessarily on geographic differentiation of storm petrels (Hydro- their taxonomical status, with the general objective of bates pelagicus) based on cytochrome b mithocondri- al DNA variation. Marine Biology 145: 1257-1264. preventing irreplaceable units of biodiversity from Catalisano A, Lo Valvo F, Lo Verde G, Massa B 1988. Dati becoming extinct. biometrici sull’Uccello delle tempeste (Hydrobates pelagicus). Atti IV Convegno italiano di Ornitologia, Il Naturalista siciliano 12 (suppl.): 261-265. Acknowledgements - I thank very much the members of Clouet M 2003. Taille du bec et période de reproduction the executive board of the Centro Italiano Studi Ornito- chez les Beccroisés des forets de pins. Revue d’Ecolo- logici (Emiliano Arcamone, Fausto Barbagli, Giovanni gie (Terre Vie) 58: 419-433.

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