Massimiliano Di Vittorio

Factors influencing the distribution, abundance and nest‐site selection of an endangered Egyptian vulture (Neophron percnopterus) population in Sicily

The Egyptian vulture ( Neophron percnopterus ) breeds in Sicily and, in 22 years of monitoring, has shown a decline followed by a slight recovery. We used Generalised Linear Models to predict: (1) the distribution range, (2) the habitat selection within the range, (3) the quality (i.e., occupation rate, breeding success) of breeding sites. Some 60% of Sicily proved to be unsuitable, being either too densely forested and without cliffs for nesting, or too densely populated, along with intensive agriculture. The models converged, indicating that the pairs select a precise upland habitat where low cliffs, distant from urban areas, are surrounded by arboreal crops and Mediterranean vegetation. The variables predicting the quality of a site are also related to human disturbance, including the distance from a road or the presence of heavy traffic. Natural restocking, in the last 3 years, is occurring in quiet sites and in proximity to extensive grazing land rich in sheep and goat herds. These results focused on short-term programmes for local management of the species aimed at protracting the natural restocking: namely, the activation of (1) a stable system of artificial feeding stations, (2) nest site protection with joint activities for increasing public awareness, (3) a reintroduction project, by hacking, of juveniles born in captivity in Italian and European breeding centres.

Status of Egyptian Vulture (Neophron percnopterus) in Sicily

Resumen La poblacion del buitre Neophron percnopterus en Sicilia se encuentra restringida a los sectores central y oeste de la isla. La poblacion alcanzo cerca de 30 parejas durante el periodo entre 1970 y 1980, auque durante nuestro periodo de estudio (1990–2007), la poblacion tuvo un tamano promedio de solo 7 ± 2 parejas mas 2 ± 1 individuos no emparejados, con fluctuaciones considerables en los numeros. Las tasas reproductivas durante nuestro periodo de estudio (juvenil por pareja reproductiva y juvenil por nido exitoso) fueron tipicas para una poblacion europea, aunque la tasa de exito de los nidos disminuyo y el abandono de nidos durante el periodo 2000–2007 fue el doble del registrado durante el periodo 1990—1999. La reduccion en la cantidad de ganado muerto y en la disponibilidad de alimento, como tambien el aumento de la perturbacion humana cerca de los sitios de anidacion, probablemente alteraron la cualidad de los territorios de cria, y son probablemente la causa de la disminucion del exito de a...

Living on the Edge: Assessing the Extinction Risk of Critically Endangered Bonelli’s Eagle in Italy

Background The population of Bonelli’s eagle (Aquila fasciata) has declined drastically throughout its European range due to habitat degradation and unnatural elevated mortality. There are less than 1500 breeding pairs accounted for in Europe, and the species is currently catalogued as Critically Endangered in Italy, where the 22 territories of Sicily, represent nearly 95% of the entire Italian population. However, despite national and European conservation concerns, the species currently lacks a specific conservation plan, and no previous attempts to estimate the risk of extinction have been made. Methodology/Principal Findings We incorporated the most updated demographic information available to assess the extinction risk of endangered Bonelli’s eagle in Italy through a Population Viability Analysis. Using perturbation analyses (sensitivity and elasticity), and a combination of demographic data obtained from an assortment of independent methods, we evaluated which demographic parameters have more influence on the population’s fate. We also simulated different scenarios to explore the effects of possible management actions. Our results showed that under the current conditions, Bonelli’s eagle is expected to become extinct in Italy in less than 50 years. Stand-alone juvenile mortality was the most critical demographic parameter with the strongest influence on population persistence with respect to other demographic parameters. Measures aimed at either decreasing juvenile mortality, adult mortality or decreasing both juvenile and adult mortality resulted in equivalent net positive effects on population persistence (population growth rate λ>1). In contrast, changes aimed at increasing breeding success had limited positive effects on demographic trends. Conclusions/Significance Our PVA provides essential information to direct the decision-making process and exposes gaps in our previous knowledge. To ensure the long-term persistence of the species in Italy, measures are urgently needed to decrease both adult mortality due to poaching and juvenile mortality due to nest plundering, the top ranking mortality causes.

Habitat preferences of Bonelli's Eagles Aquila fasciata in Sicily

Capsule For breeding, areas dominated by extensive agricultural and rugged Mediterranean landscapes are preferred; maintenance of habitat heterogeneity and extensive agriculture are key for the conservation of this eagle. Aims To model breeding habitat preferences of Bonellis Eagles Aquila fasciata in Sicily, where the last viable population still remains in Italy, in order to identify the most important habitats for conservation. Methods Pairs were monitored between 1990 and 2010. A case-control design through glms was used at two spatial scales: landscape and home-range. Variables included topographic, climatic, land-use, road and descriptors of habitat heterogeneity. Information-based criteria were used to select the best subset of predictors. Results A total of 22 breeding pairs are still breeding, which represent about the 90% of the Italian population. The best models at both scales showed that Bonellis Eagles were clearly associated with Mediterranean features, including rugged areas surrounded by extensive arable land, shrubland and herbaceous vegetation. Our results emphasize the negative effects of habitat fragmentation and agricultural intensification on the probability of occurrence of Bonellis Eagles. Conclusion The distribution of Bonellis Eagles in Sicily can be described by a relatively small number of topographical and land-use variables. The maintenance of habitat heterogeneity is key for the conservation of this endangered raptor.

Ecological Modelling of the Distribution of the Lanner Falcon Falco biarmicus feldeggii in Sicily at Two Spatial Scales

Summary. The presence of the lanner falcon Falco biarmicus feldeggi in Sicily was modelled by generalized linear models using climatic, topographic, ecological and land-use variables at both the landscape (UTM cells of 10 × 10 km) and the home range (12.56 km2) spatial scales. At the landscape scale, a significant spatial autocorrelation of the lanner population, corresponding to the longitudinal distribution of sites, was found, with the species occurring within the most xeric UTM cells. There was also a negative relationship between falcon presence and potential evapo-transpiration values, either in the coldest months or throughout the year. The same negative relationship was also seen with the surfaces of CORINE artificial areas, thus showing that the species has a low tolerance to any anthropogenic landscape. At home range scale, our predictive models revealed a preference for territories with steep slopes surrounded by natural grassland, sclerophyll vegetation, arable land and agricultural land. The lack of spatial correlation and the identification of specific preferred land use classes, suggests that the home range scale is more appropriate than the landscape scale for predicting the occurrence of lanner falcons. The maintenance of a stable lanner falcon population in Sicily should be addressed at both small and large scales.

SUCCESSFUL FOSTERING OF A CAPTIVE-BORN EGYPTIAN VULTURE (NEOPHRON PERCNOPTERUS) IN SICILY

The critically endangered Italian population of Egyptian Vultures (Neophron percnopterus) lives in the central-southern Apennines and in Sicily (Liberatori and Massa 1992, Pages 488–493 in P. Brichetti, P. De Franceschi and N. Baccetti [EDS.], Fauna d’Italia Aves I. Edagricole, Bologna, Italy; Lo Valvo, Massa, and Sarà 1993, Naturalista siciliano 17:54–55). The Sicilian population experienced a sharp decline from some 30 pairs in 1970–80 (Iapichino and Massa 1989, The birds of Sicily. British Ornithologists’ Union, London, U.K.), to three pairs in 1997; since then, the population has been monitored annually and has increased to 10–13 pairs (Sarà and Di Vittorio 2003, Animal Conserv. 6:317–328). In this study, we tested the viability of the fostering of juveniles born in captivity. Successful fostering has been accomplished for many species of raptors and vultures, and fostering is considered one of the tools available for restocking wild populations (Frey and Bijleveld 1994, Pages 459–464 in B.-U. Meyburg, and R.D. Chancellor [EDS.], Raptor conservation today, WWGBP, Berlin, Germany; Terrasse et al. 1994, Pages 479–492 in B.-U. Meyburg and R.D. Chancellor [EDS.], Raptor conservation today, WWGBP, Berlin, Germany). For the Egyptian Vulture, there are only a few records of fostering of alien chicks (Donàzar and Ceballos 1990, Ibis 132:603–617; Levy and Segev 1996, Pages 415–424 in J. Muntaner and J. Mayol [EDS.], Biology and conservation of Mediterranean raptors, SEO, Madrid, Spain; Corsange, Perennou, and Gallardo 2005, Alauda 73:21–24). In 2003 we selected two territories as candidates for the fostering trial based on three criteria: (1) regular and consecutive breeding at that territory during the last 5 yr, (2) a nest structure large enough to host the additional chick and (3) a location in a secluded portion of a nature reserve. In March 2003, we established two small feeding stations, which we supplied with 10–15 kg of entrails and meat chops weekly. The two pairs of vultures immediately used the feeding stations, laid eggs approximately 20–25 April, and raised two chicks each to fledging (a common occurrence in Sicily, where, since 1995, 30% of 46 successful pairs fledged two young; M. Sarà and M. Di Vittorio unpublished data). Ideally, we believe that it would be better to choose a foster pair with only one natural chick, in order to avoid burdening the parents with the feeding of three chicks, and to minimize nestling competition for food and space within the nest. On 28 July 2003, a 60-d-old Egyptian Vulture (hatched 28 May 2003 at the World Wildlife Fund Breeding Center of Semproniano) was placed into the larger and more accessible of the two candidate nests. The two Egyptian Vulture wild nestlings and the foster nestling were weighed and banded; in addition, one of the wild chicks and the foster chick were tagged with satellite transmitters. The nestlings were monitored continuously for 2 wk (until fledging) and observers were prepared to intervene and rescue the foster chick, in case of any detected or potential risk. The foster chick was immediately accepted by the two wild nestlings and after just 1 hr the three chicks stayed calm and close to each other. Four hours after the introduction, both adults landed on the nest, and immediately accepted the new chick without any sign of aggressiveness. In the following days, adults regularly fed all the nestlings, taking advantage of the close feeding station. The foster nestling was in general much noisier and begged for food more frequently than its acquired siblings. On 11 August 2003, the two wild juveniles left their nest at 0700 H, followed by the fostered young at 0930 H. One day after fledging, the three young flew back into the nest and in the following days returned to the nest at various times. We were able to track the family in the surrounding area until 28 August 2003. Dispersal from the breeding site occurred at the end of August, the usual period for this population. Our fostering experiment seemed successful; both foster parents and the acquired siblings accepted the fostered nestling. The presumed heavy charge of feeding three chicks seemed well supported by the parents, which probably benefited from the artificial feeding. Our experiment gave some promising indications for the use of fostering to restock wild populations of Egyptian Vultures in areas where lowered natural recruitment may not be sufficient to ensure population persistence. This work was funded by the Università Palermo, ‘‘ex-60%, 2004: Gestione della biodiversità (Vertebrati Terrestri) e degli Habitat d’interesse comunitario (SIC e ZPS)’’ and by the Stazione Inanellamento Assessorato Agricoltura e Foreste Regione Sicilia. G. Ceccolini of the WWF Breeding Center of Semproniano (GR) provided the foster chick and assisted in the project. We also thank S. Grenci for field assistance.—Massimiliano Di Vittorio, Dipartimento di Biologia Animale, Via Archirafi, 18 90123 Palermo, Italy; Salvatore Falcone, Via Roccaforte, 53–90011 Bagheria

Bushmeat consumption in the West African Sahel of Burkina Faso, and the decline of some consumed species

To explore the patterns of bushmeat trade in the Sahel we carried out a multidisciplinary study, focusing on Burkina Faso. We conducted baseline interview surveys to examine the variation in peoples perceptions of bushmeat in relation to their place of residence (urban vs rural), sex and age. We also analysed the long-term (1985–2010) population dynamics of two ungulate species, the oribi Ourebia ourebi and the common duiker Sylvicapra grimmia, known to be among the main targets of the bushmeat trade locally. For the antelopes we chose as our study area a protected area (Nazinga Game Ranch) where poaching activities occur and are likely to represent a threat to the local wildlife. The results of the interviews underlined significant differences in bushmeat consumption between rural and urban areas. In particular, the probability of finding people who did not consume bushmeat increased in the urban area, where bushmeat is less available than in the rural areas. Sex and age did not have any effect on peoples perceptions of bushmeat. In Burkina Faso bushmeat is still widely consumed, and this could be because the bushmeat trade is poorly controlled, with a lack of enforcement of the legislation. Long-term field surveys revealed that the oribi and the common duiker have declined significantly in Nazinga Game Ranch, suggesting that the bushmeat trade in Burkina Faso may have negative consequences in terms of the conservation outlook for these species.

La ricchezza specifica dei Vertebrati in Sicilia

The ‘Atlas of Sicilian Vertebrates’ recorded the distribution of Vertebrates during the 1993-2006 on a UTM grid with cells of 10 x 10 km. Excluding the Chiropterans and all the vertebrates living on the surrounding small islands, 193 species (7 Amphibians, 18 Reptiles, 147 Birds, 21 Mammals) resulted to be present in Sicily. Preliminary investigations found a statistically significant correlation among species richness of each class in the UTMs, which means for example that the richest cells in Amphibians were also the richest in Reptiles, Birds, etc. This correlation persisted when the area-effect was removed by excluding all peripheral cells that included coastland smaller than 100 km2. There is a low probability that such correlation was an artefact due to the differential sampling efforts across Sicily because censuses were conducted by a high number of collaborators who acquired a thorough territorial knowledge during this study. We thus hypothesised that some macro-ecological variables could be responsible for the distribution of species richness in the territory. We considered 61 variables belonging to 13 climatic, physiographic and land use data-sets. They were preliminarily treated to rule out auto-correlation and collinearity. This procedure allowed us to extract 25 independent predictors that we regressed on species richness per each Class and on the total Vertebrate richness in the UTM cells by using the GRM method and a forward stepwise selection of variables. Most variation of total vertebrate richness in Sicily was explained by a limited set of 5 variables: 2 Corine Land Covers (forests and semi-natural areas; wetland and water corpses) and 3 climatic (annual potential evapo-transpiration range, annual mean temperature excursion and De Martonne’s aridity index). Bird species richness was explained by the whole set of 5 variables, whereas a more restricted set explained the distribution of Amphibian (forests and semi-natural areas; wetland and water corpses; annual potential evapo-transpiration range), Reptile (forests and semi-natural areas; annual potential evapotranspiration range) and Mammal (annual potential evapo-transpiration range; annual mean temperature excursion) species richness. The UTM cells with highest values of species richness were characterized by an annual potential evapo-transpiration range 1.5 times larger than in the poorest cells, and by a threefold annual mean temperature excursion. The extension of forests, semi-natural areas, wetlands and water corpses were, on average, twofold than those in the poorest areas. More species, generally Birds, live in driest areas as shown by the inverse relationship between the De Martonne’s aridity index and species richness. Apparently, in the area equivalent to a UTM cell of 100 km2, the wider is the range of climatic variation, the larger becomes the environmental heterogeneity. This, in turn, provides more suitable habitats and potential niches for species.

First assessment of age and sex structures of elephants by using dung size analysis in a West African savannah

Abstract 1. An age and sex structure study of the West African savannah elephant (Loxodonta africana africana) population of the Nazinga Game ranch (Burkina Faso) was carried out using direct sightings of individuals near water points, where they group during hot periods of the day, and droppings circumference measurements of dung pile along line transects, during the dry seasons of 2007 and 2008. The age structure, from direct observation data, was estimated by classifying the individuals into 9 age-class-categories based on body size and eruption (length) of tusks. 2. The frequency distribution of number of individuals into the age-class-categories showed high similarity with the distribution of circumference measurements of dung-piles that the individuals were seen depositing. Fifty dung-piles measured soon after they were deposited (Class A) and after they dried (to class C) showed a significant difference between the circumference measurements in relation to the time elapsed between the measurements. 3. The frequency distribution of dung circumference classes of the observed elephants was similar to that of the dung-piles measured along the transects in 2008. Therefore, dung-piles measurements were used to estimate the Nazinga Game Ranch savanna elephant population’s age and sex structures at the end of dry seasons of 2007 and 2008. We advocated that the Nazinga elephant population consisted mainly of sub-adults. 4. The sex ratio was estimated to be in favour of females (1/2). The age-class-specific sex ratio was uneven for calves and young individuals, while being in favour of females with adults. Individuals of less than 1 year represented 6% of the population during the study period.

Selective disturbance by elephants (Loxodonta africana) on eight tree species in a West African savannah

African elephants (Loxodonta africana) are ecosystem engineers in African savannahs, but their role in the modifications of the populations of trees by means of their browsing activities has been poorly studied so far in West Africa. We studied the disturbance of elephants to eight selected species of trees in the Nazinga Game Ranch (Burkina Faso), in 54 transects at the end of dry season 2008. We fitted simple models describing the number of dead individuals for each tree species in relation to their initial population density, and in relation to dung-pile density, in the assumption that there should be a positive relationship between elephant density and dung-pile density. Generalized Linear Model analyses and regression analyses showed that the more dense the woodland cover, the least the percentage of damaged plants by elephants. For each plant species, the initial density and density of elephant dung-piles explained a high proportion of the variance in the density of dead individuals. Stochastic models, generated by a purposely created simple computer program written in GW-BASIC programming language, predicted changes in tree and shrub abundance under different assumptions about elephant numbers. The models suggested that elephant browsing may cause considerable change in the selected plant populations, especially with regard to such species as Acacia gourmaensis, Vitellaria paradoxa and Maytenus senegalensis. These changes may possibly increase the meat harvest from controlled hunting activities, thus improving the income for surrounding communities.