ISSN 1827-9635 (print) © Firenze University Press ISSN 1827-9643 (online) www.fupress.com/ah Acta Herpetologica 9(1): 51-59, 2014 DOI: 10.13128/Acta_Herpetol-12667 Habitat selection in the fossorial toad Pelobates fuscus insubricus (Amphibia: Pelobatidae): does the soil affect species occurrence? Loredana Carisio1, Roberto Sacchi2, Daniele Seglie3, Roberto Sindaco4,* 1 Regione Piemonte, Osservatorio Regionale sulla Fauna Selvatica, corso Stati Uniti 21, 10100 Torino, Italy 2 Dipartimento di Scienze della Terra e dell’Ambiente, University of Pavia, Via Taramelli 24, 27100, Pavia, Italy 3 Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina, 13, 10123 Torino, Italy 4 Istituto per le Piante da Legno e l’Ambiente, corso Casale, 476, 10132 Torino, Italy. *Corresponding author. E-mail: rsindaco@gmail.com Submitted on 2013, 13th April; revised on 2013, 21st November; accepted on 2014, 5th March Abstract. For their rapid and alarming decline, the Italian populations of the Italian spadefoot toad (Pelobates fus- cus insubricus) are of high conservation importance. In this study we examined habitat use by the spadefoot toads in north-west Italy, where one of the largest remaining populations lives. We used compositional analysis and logis- tic regression models to elaborate land-use and soil composition in order to determine the habitat preferences of the spadefoot toads. We found that the two main variables predicting the occurrence of spadefoot toads in the study area were the percentages of sandy-loam soil texture and the presence of Entisols. Our results showed that spadefoot toads preferred soils that keep soft and malleable structure: Entisols with sand texture, where sand represents the major component, and mature soils, with a high degree of pedogenesis and a relatively high natural fertility and humidity. Conversely, Pelobates fuscus avoids Inceptisols, probably too hard to be dug by the species. This study demonstrates that, at least in the Italian range, the choice of areas in which to reintroduce P. fuscus, or where re-create favourable habitats for it, must take into account the soil types, which, in intensely cultivated areas, seems to be decisive for the possibility of survival of the species in the medium and long time. Keywords. Spadefoot toad, terrestrial habitat, soil, compositional analysis, conservation. INTRODUCTION A central goal of conservation is to identify the main factors affecting the presence and abundance of species at large scales over long periods of time. Only when favour- able and unfavourable factors are known, it is possible to take appropriate conservation measures, in order to reduce the negative impacts and improve the environ- mental conditions to the advantage of the species. The spadefoot toad (Pelobates fuscus) is a fossorial amphibian widely distributed in Europe. In last century populations declined dramatically in the northern and western parts of its range, where several local extinctions were documented (France: Lescure, 1984; Parent, 1985; Dubois, 1998; Belgium: Rappè, 1982; Perczy, 1994; Neth- erlands: Pelt and Van Bree, 1965; Denmark: Fog et al., 1997; Gislen and Kauri, 1959; Sweden: Berglund, 1998). In Italy, where the species was probably widespread in the whole Po Plain in the XIX century, it currently occurs in a few isolated populations (Andreone, 2006). Despite new breeding sites have been recently discov- ered (Mazzotti et al., 2002; Andreone et al., 2004; Mer- curio and Li Vigni, 2007), the total number of known breeding sites has dramatically reduced since the end of the XX century (Andreone et al., 2004), and the species is considered one of the most threatened amphibians in Italy (Rondinini et al., 2013). For example, in Piedmont, out of 21 reproductive sites known in 1985, only 7 still exist despite several conservation projects (D. Seglie, pers. obs.). 52 L. Carisio, R. Sacchi, D. Seglie, R. Sindaco The decline of spadefoot toad in Italy is due to several concurrent causes, including the drastic reduc- tion and alteration of suitable habitats, the increase of intensive agriculture, the change of agricultural prac- tices in the ricefields, the worsening of water-quality, and the progressive fragmentation of the residual natu- ral habitats. Additional threats are the introduction of fishes and allochthonous crayfishes (e.g., Procamba- rus clarkii), and possibly the introduction of alloch- thonous amphibians such as Lithobathes catesbeianus (Andreone, 2006; Andreone et al., 2007), which may convey amphibian pathogens like Batrachochytrium dendrobatidis. However, this fungus has not yet been found on Pelobates fuscus (Federici et al., 2008) in the areas of the Piedmont where it affects other amphibians (Adams et al., 2008). The conservation of the Italian populations of the spadefoot toad is of particular interest, since they are considered as belonging to an endemic subspecies, P. f. insubricus, which is listed in the Annexes II and IV of the Habitat Directive 92/43/CEE as priority species. From the taxonomic point of view, this subspecies is separated from the other European populations on the base of genetic distinctiveness and some morphologi- cal and acoustic features (Héron-Royer, 1888; Andreone and Piazza, 1990; Andreone et al., 1993). However, while several authors recognize the Italian popula- tions as a distinct subspecies (Nöllert and Nöllert, 1992; Andreone et al. 1993), its validity is still debated (Andreone et al., 2007; Crottini et al., 2007). The genetic study of Crottini et al. (2007) confirmed that Po Plain populations keep a very high genetic variability within the “western” lineage, and a high number of haplotypes not found elsewhere in Europe. This high genetic vari- ability indicates that the Po Basin was one of the most important glacial refugia for the species during the Pleistocene. As far as its ecology, in northern Europe the occur- rence of P. fuscus is determined by the interaction between pond features and hydroperiod with the occur- rence of large predators such as fishes and crayfishes. Breeding sites are large permanent ponds with high spring temperatures, high concentrations of phospho- rus and oxygen, and a shoreline with a high proportion of steep banks (Strijbosch, 1979; Nyström et al., 2002). By contrast, composition of the terrestrial habitat close to the ponds and traffic has no or low effect on P. fuscus occurrence (Nyström et al., 2002). In Italy P. fuscus occurs in lowlands up to 400 m a.s.l. (Andreone, 2006) and does not appear to be very selec- tive for habitats with the exception of areas with sub- strates soft enough to allow burrowing, such as sandy soils (Lanza, 1983; Andreone et al., 1993; Gentilli and Scali, 2001). Indeed, it has been found in woods, mead- ows, poplar plantations, cereal crops and ricefields (Lan- za, 1983; Andreone et al., 1993; Fortina and Andreone, 1999; Mazzotti et al., 2002; Scali and Gentilli, 2003). Dur- ing the breeding season the species has been reported to use different types of wetlands, from ponds and marsh- es to ditches, almost all temporary sites, usually in open areas (Lanza, 1983; Scali and Gentilli, 2003; Andreone et al., 2007). However, no quantitative analyses on habitat preference have been carried out so far in Italy, probably because of species rarity, the low consistence of residual populations and the difficulty to locate the spadefoot toads in the field (Andreone et al., 2004). Similarly, few studies have been carried out on habitat use outside the breeding season (Eggert, 2002; Bosman and Van Den Munckhof, 2006). In this paper, we analysed the habitat preference of spadefoot toads in the last population settled south the city of Turin; the main objective was to detect some of the habitat features surrounding breeding areas, with par- ticular emphasis on soil, which could explain the pres- ence/absence of the species in order to supply detailed information useful to develop management and conser- vation programs. MATERIAL AND METHODS Study area and collecting data The study area (Fig. 1) includes a portion of the alluvial plain south the city of Turin and is delimited southwards by the towns of Carmagnola (44°50’N, 7°53’E), Poirino (44°55’N, 7°50’E) and Santena (44°56’N, 7°46’E). This area hosts one of the last populations of spadefoot toads of Piedmont, which breeds in several small and medium-large ponds that are included within the Site of Community Importance (hereafter SCI) “Stagni di Poirino-Favari” (IT111035), extended over an area of about 1,840 hectares (Sindaco et al., 2009). Since the discovery of the species (by G. Boano in 1989), the area was thoroughly monitored by many researchers (see Acknowledgments), mostly during night transects conducted through low-speed driving on paved and gravel roads. The data were collected between 1988 and 1991, during March-May (cor- responding to the activity period of the species in this area), and account for 70 individuals. The research effort has been constant over the entire area, as all the roads of the study area were covered with the same intensity. The position of each toad was accurately recorded on the topographic maps of the Italian Military Geographical Institute (I.G.M.) at the scale 1:25.000, and then mapped using a GIS. The localities of P. fuscus in the Turin area (Fig. 2) are derived from the available literature and the database of the regional herpetological atlas (Andreone and Sindaco, 1999). 53Habitat selection in Pelobates fuscus insubricus Habitat variables We investigated habitat selection by spadefoot toads by assessing the evolution and texture of soil and the land use in the 70 spots were P. fuscus was found (Fig. 1), and in 150 spots randomly selected within a 50 m buffer along the transects. The habitat variables accounted for soil type, soil texture and landcover, and were measured using digital maps of the Regione Piemonte (surveyed at the scale scale 1 : 10.000, pub- lished at the scale 1:50.000) (http://www.regione.piemonte.it/ agri/area_tecnico_scientifica/suoli/suoli1_50/carta_suoli.htm), reporting the degree of pedogenesis and soil texture according to the USDA classifications (http://soils.usda.gov/technical/clas- sification/taxonomy/). Our study area involved six main soil types, i.e., Alfisols with or without hydromorphisms (classes A1 and A3 respec- tively), Inceptisols with or without hydromorphisms (classes B1 and B2 respectively), and Entisols with or without hydro- morphisms (classes C1 and C2 respectively). Since classes A1, B2, and C2 covered less than 5% of the study area, they were grouped in the same class. Therefore, in our analyses we used only four classes of soil evolution: Alfisols (A3), Inceptisols (B1), Entisols (C1), and other soils (A1, B2, C2 combined). Only five out of the twelve possible soil textures are present in the study area, with different percentages of sand and silt, from sandy soils (sand and loamy-sand classes, with more than 90% and 70% of sand respectively, in weight), intermediate soils (sandy-loam and loam classes, with 40-70% of sand) and silty soils (silt-loam class, with less than 40% of sand). In all these five classes clay occurs in no more than 20-25%. Although the soil data go back over about 15 years ago, these data are still valid, because in agricultural landscapes the pedogenesis will stop in the topsoil, or at least slow down significantly, while in depth it continues. However, the soil composition does not change in a few decades (I. Boni, pers. comm.). Finally, habitat types were grouped in five main catego- ries: urban areas (urban areas, parks and gardens within towns), woods (oak-hornbeam and locust woods), cultivated fields (maize, sunflower, and alfalfa), and poplar plantations. Remnant habitat types were combined in a single group, which cover less than 5% of the study area. To compare the incidence of the aforementioned vari- ables in places where P. fuscus individuals were detected, we considered 220 plots with a 50-m radius, centred on the point of observation of P. fuscus (70 plots), and on 150 random points (see above). Moreover, we calculated the distance (in meters) from each plot to the border of the nearest urbanized area and to the nearest pond. Fig. 1. Findings of Pelobates fuscus insubricus in the SCI IT1110035 “Stagni di Poirino - Favari” between 1988 and 1991. 54 L. Carisio, R. Sacchi, D. Seglie, R. Sindaco Statistical analyses We used a t-test to check for differences between species and random plots in mean distances from the nearest urban area and the nearest pond. Since soil variables were highly intercorrelated (Suppl. Mat. Table T1), we used the composi- tional analysis (Aebischer et al., 1993) to rank the soil evolution, soil texture and land-use variables according to their impor- tance in promoting (or disfavouring) spadefoot toad occur- rence. Habitat availability was estimated using the random plots, while the Wilk’s lambda, determined by randomization tests, was used to assess the significance of the ranking matrix Fig. 2. Historical and current distribution of Pelobates fuscus insubricus in the plain south of Turin. Grey (intermediate gray): urbanized areas; red (dark gray): high suitable soils; yellow (light gray): suitable soils; white: unsuitable soils. Populations: 1) Piobesi T.se env., 2) right bank of Po river between Carignano and Carmagnola; 3) Carmagnola – San Michele; 4) Carmagnola – Cervirola and Tetti Grandi; 5) Car- magnola – Casanova and env.; 6) Moncalieri – Testona, 7) Rivoli, 8) Torino – Vanchiglia, 9) the study area. The species has been confirmed in recent times only in loc. 2 and 9. Colour legend between brackets refers to the printed version of the image (black and white). 55Habitat selection in Pelobates fuscus insubricus (Aebischer et al., 1993). In order to assess the potential effects of soil and land use variables on the occurrence of spadefoot toads, logistic regression models were developed to identify the most important variables likely affecting toad presence. Since variables were intercorrelated, we developed all possible three- predictor models using one variable for soil evolution, one for soil texture and one for habitats respectively, in a way that every variable within each environmental group entered the same number of models. Following this procedure we built 100 models (4 texture soils × 5 soil evolution classes × 5 land-use variables). Inference from models was made according to the Information-theoretic approach (Anderson et al., 2000; Ander- son and Burnham, 2002; Mazerolle, 2006): for each model, we computed the differences with the minimum AIC (ΔAIC) and Akaike weights (wAIC), and we ranked models according to this last index. The relative importance of predictor variables was measured by the sum of the models Akaike weights (Σw) where each variable appeared (Anderson and Burnham, 2002). To quantify the effects of the predictor variables the β (par- tial regression coefficients) were weighted and averaged on the models obtained β. The unconditional sampling variance (var β) and 95% confidence intervals were computed for all predictors in order to assess their statistical significance (Anderson and Burnham, 2002). All analyses were performed using the soft- ware R (R Development Core Team, 2010), and data reported are means and standard errors, unless otherwise stated. To meet the assumptions of the analyses, data in proportions were arc- sine transformed prior to analysis. RESULTS The P. fuscus presence plots were significantly closer to the nearest pond (presence plots: 557.3 ± 43.7 m, ran- dom plots: 1014.2 ± 82.7 m; Welch two samples t-test: t = 7.581, df = 180.8, P < 0.001) and significantly apart from the nearest urban area (presence plots: 213.7 ± 26.9 m, random plots: 147.7 ± 14.0 m; Welch two samples t-test: t = 2.172, df = 107.7, P = 0.032) than randomly selected ones. The compositional analysis for the variables con- cerning the evolution of soil generated a highly signifi- cant ranking matrix (Λ = 0.752, P = 0.002), confirming that Alfisols and Entisols were preferred by the spade- foot toads, whereas Inceptisols were significantly avoided (Table 1). The ranking matrix was highly significant also as far as soil textures (Λ = 0.475, P = 0.002), and indicat- ed that sandy-loam soils were clearly preferred by toads, followed by sand and silt-loam ones, whereas loamy-sand soils were overall avoided (Table 2). The ranking of habi- tat variables by compositional analysis was less clearly defined with respect to that obtained for the soil vari- ables. Indeed, even if the ranking matrix was highly sig- nificant (Λ = 0.339, P = 0.002), it did not show a striking preference for a specific habitat but only a small prefer- ence for poplar plantations (Table 3). As expected, urban- ized areas were avoided by the species. The multi-model inference showed that P. fuscus occurrence was mainly influenced by sandy-loam soil texture, Entisols, poplar plantations, and urban areas (Table 4). The relatively major importance of the sandy- loam soil texture and Entisols was empirically sup- ported by the high values of the sum of Akaike weights for the models where the variables appeared (sandy- loam soils: Σw = 0.98; Entisols: Σw = 0.96). Their effects Table 1. Ranking matrix of soil evolution variables comparing pro- portional soil use within plots of species occurrence with propor- tions of total available soil types evaluated in random plots. Each mean element in the matrix is represented by its sign. When the sign occurs three times it represents a significant deviation from random at P < 0.05. Alfisols Entisols Other soils Inceptisols Alfisols + + + + + + + Entisols − + + + + + + Other soils − − − − − − + + + Inceptisols − − − − − − − − − Table 2. Ranking matrix of soil texture variables comparing pro- portional texture use within plots of species occurrence with pro- portions of total available texture types evaluated in random plots. Symbols as in Table 1. Sandy- loam Sand Silt-loam Loam Loamy- sand Sandy-loam + + + + + + + + + + + + Sand − − − + + + + + + + Silt-Loam − − − − Loam − − − − − − − − − + + + Loamy-sand − − − − − − − − − − − − Table 3. Ranking matrix of habitat variables comparing proportion- al habitat use within plots of species occurrence with proportions of total available habitat types evaluated in random plots. Symbols as in table 1. Poplar plantations Woods Cultivated fields Other habitats Urban areas Poplar plantations + + + + + + + + Woods − + + + + + + + Cultivated fields − − Other habitats − − − − − − − − − + + + Urban areas − − − − − − − − − − − − 56 L. Carisio, R. Sacchi, D. Seglie, R. Sindaco on the occurrence of P. fuscus were largely positive as expressed by estimating the regression coefficient using model averaging (sandy-loam soils: β = 3.59; Entisols: β = 2.21), even when models uncertainty was accounted for (β 95% confidence interval ranged from 2.02 to 5.15 for sandy-loam soils and from 1.35 to 3.06 for Entisols). Poplar plantations (Σw = 0.51) and urban areas (Σw = 0.36) were the third and the fourth predictors in order of importance. Percentage of poplar plantations had a posi- tive effect on spadefoot toad occurrence (β = 1.46; 95% confidence interval ranged from 1.19 to 1.73), whereas the effect of urban areas was negative (β = -0.76; 95% confidence interval ranged from -0.94 to -0.58). All other variables had Σw less than 0.10, having a minor effect on P. fuscus settlement. DISCUSSION Habitat selection In this paper we showed that the spadefoot toad has specific habitat requirements in our study area; its occur- rence was primarily associated with the conditions of soils, and the two most important variables predicting its distribution were the percentage of sandy-loam soil texture and the presence of Entisols. Nonetheless, these two variable were not highly intercorrelated (Pearson’s rp = -0.18), but sandy-loam texture was mainly associated to Alfisols (rp = 0.45), whereas Entisols related princi- pally with sand soil texture (rp = 0.79). Therefore, spade- foot toads occurs in two opposite soil conditions: on one hand the soils showing any profile development other than a small A horizon, basically unaltered from their parent material, where sand represents the major compo- nent (Entisols with sand texture); on the other hand the mature soils, with an high degree of pedogenesis, a well evident three-horizons profile, and a relatively high native fertility and humidity. In this last case, the percentage of sand remained high, but a relevant portion of silt and clay was also present. Despite their different composition, both types of soils keep a soft and malleable structure that can easily be dug. Spadefoot toads in our study area avoided the Incep- tisols, which are of relatively recent origin, having only a weak appearance of the horizons produced by pedo- genesis. The humus does not accumulate in layers, but is mixed with the mineral matrix in a more thin texture (loam and silk-loam; Suppl. Mat. Table T1) with respect to the two other dominant soils. Consequently, the soil is denser and uneasy to be dug by the toads. A second relevant result of this study was the nega- tive impact of urban areas, which confirms that the dis- turbance by human presence and activities is among the main causes of the decline of the species. The negative effect of urban areas can be explained by several con- comitant conditions: the progressive erosion of suitable habitats due to the expansion of the metropolitan area of Turin (inhabited by about 1,700,000 people), the increase of barriers (mainly roads) among breeding sites that seg- regates the population in smaller and more isolated sub- populations, and the direct killing due to traffic load. Table 4. Multi-model inference on models parameters and relative importance of the 14 soil and land-use variables used for analysing habi- tat selection by P. fuscus: Σw, Akaike weights; β, averaged weighted partial regression coefficient; SE(β), standard error of β; Lower CI95% and Higher CI95%, confidence interval at 95%. Variabile Σw β SE(β) Lower CI95% Higher CI95% Sandy-loam 0.9810 3.5857 0.7998 2.0180 5.1534 Entisols 0.9619 2.2067 0.4346 1.3549 3.0585 Poplar plantations 0.5085 1.4634 0.1389 1.1912 1.7356 Urban areas 0.3583 -0.7623 0.0912 -0.9410 -0.5836 Woods 0.0820 0.2689 0.0619 0.1475 0.3902 Other habitats 0.0264 -0.0187 0.0128 -0.0437 0.0063 Cultivated fields 0.0248 0.0006 0.0038 -0.0068 0.0081 Loamy-sand 0.0190 -0.0601 0.0132 -0.0859 -0.0343 Inceptisols 0.0155 -0.0185 0.0039 -0.0261 -0.0109 Other soils 0.0126 -0.9625 11.5472 -23.5950 21.6700 Alfisols 0.0099 0.0143 0.0031 0.0082 0.0203 Sand 4.6×10-08 1.1×10-07 2.63×10-08 6.2×10-08 1.6×10-07 Silt-loam 5.7×10-10 -1.3×10-09 3.6×10-10 -2.0×10-09 -6.0×10-10 Loam 3.7×10-10 -3.3×10-10 9.1×10-11 -5.0×10-10 -1.5×10-10 57Habitat selection in Pelobates fuscus insubricus Despite traffic load had not been found to be a relevant threat in northern Europe populations (Hels and Buch- wald, 2001; Nyström et al. 2002), the proportion of toads killed might be relevant in our study area, since many of the observed specimens were found dead on road. These results agree with the past and current presence of the spadefoot toad in the area south of Turin (Fig. 2) where it is evident the presence of populations in areas with suit- able soil and the extinction of some populations due to urbanization. Finally, we also found that poplar plantations were among the preferred habitats of the spadefoot toads, as previously reported for other Italian populations (Andreone et al., 2007). The preference for this type of habitat is only marginally dependent on the quality of soils where poplars are planted: even though poplars are cultivated preferentially in sandy-loam soils (rp = 0.18), the value of the correlation coefficient is too low to ful- ly explain the positive selection of poplar plantations by toads as a simple correlation with soils texture. Two pos- sible reasons leading spadefoot toads to prefer poplar plantations might be: 1) the fact that the large part of intensively cultivated areas of Piedmont, and in particu- lar the corn-fields, are too disturbed by deep plowing and show a fauna of invertebrates very depleted compared to poplar plantations (Casale et al., 1993); 2) the milling, which farmers regularly do in order to keep the ground under the canopy free from weeds; this practice turns over and fragments the soil, which might become softer and suitable for spadefoot toads irrespective of its origi- nal structure and texture. Conservation Due to its rarity, several conservation actions have been carried out in Italy during the last decades to protect the spadefoot toad (Andreone, 1984, 2001; Andreone et al., 1993; Fortina et al., 2000; Scali et al. 2001; Ferri, 2002; but see Andreone et al., 2004). The initial projects had mainly dissemination and education purposes (Andreone et al., 1993; Andreone, 2001), whereas the more recent ones involved also habitat management actions (Sindaco et al., 2013). The latter gave priority to identification and conservation of the main breeding sites and the surround- ing areas (Andreone et al., 2004), restoring of degraded ponds and habitats previously used for breeding (Scali et al., 2001), looking for new populations (Mazzotti et al., 2002, Mercurio and Li Vigni, 2007), digging of new ponds and tadpoles translocation (Scali et al., 2001). The reintroduction attempts failed because some essential parameters were not considered, particularly the type of breeding sites and soil characteristics (e.g., in Vanzago - Lombardy, and in Bellinzago Novarese and Agrate Conturbia - Piedmont). Despite based on a dataset dating back more than 20 years, the present paper provides soil parameters useful to identify areas suitable for the species on wide areas of the Po Valley, where the totality of the Italian populations of the spadefoot toad occurs. As well as many areas of the Po Plain, the landscape of the plain south to Turin has been rapidly transformed from an area dominated by small scale farming and numerous fish-ponds, to an area with large scale agricul- ture, increasing urbanization and industry. Several origi- nal wetlands suitable for spadefoot toads went lost, and the long term survival of the species in most of its Italian range is strictly dependent from the conservation of the residual artificial ponds within a habitat matrix with fea- tures fitting its habitat requirements. The information obtained in this study might help researchers to better identify and protect the areas char- acterized by the most suitable habitats for the species, to design actions of habitat restoring to improve the qual- ity of the existing habitats, and to detect more efficiently where the digging of new ponds might provide the best results for the breeding performance of the species. Lastly, combining the digital maps of soils now available with detailed land-use maps, large-scale mod- els of habitat suitability for the species could be devel- oped. These maps could help researchers to detect the areas where to concentrate the efforts to locate other yet unknown populations of spadefoot toads. ACKNOWLEDGEMENTS We wish to thank the people who provided many of the records of Pelobates used for this article: Riccardo Fortina, Roberto Marocco, Giovanni Boano, Giovanni Battista Delmas- tro, Franco Andreone. Paolo Martalò (I.P.L.A., Istituto per le Piante da Legno e l’Ambiente, Torino) provided information on soil composition Igor Boni (head of the Soil Department of I.P.L.A.) on soil evolution in cultivated areas. Thanks are due to Marco Mangiacotti and the anonymous referees that, with their remarks, improve the paper. Supplementary material associated with this article can be found at < http://www.unipv.it/webshi/ appendix > Manuscript number 12667: Appendix 1. REFERENCES Adams, M.J., Galvan, S., Scalera, R., Grieco, C., Sindaco, R. (2008): Batrachochytrium dendrobatidis in Amphib- ian populations in Italy. Herpetol. Rev. 39: 324-326. Aebischer, N.J., Robertson, P.A., Kenward, R.E. (1993): Compositional analysis of habitat use from animal 58 L. Carisio, R. Sacchi, D. Seglie, R. Sindaco radio-tracking data. Ecology 74: 1313-1325. Anderson, D.R., Burnham, K.P. (2002): Avoiding pitfalls when using information-theoretic methods. J. Wildlife Manage. 66: 912-918. Anderson, D.R., Burnham, K.P., Thompson, W.L. (2000): Null hypothesis testing: problems, prevalence, and an alternative. J. Wildlife Manage. 64: 912-923. Andreone F. (1984): Husbandry and captive spawning of the common spadefoot toad (Pelobates fuscus insubri- cus). Brit. Herpetol. Soc. Bull. 10: 49-51 Andreone, F. (2001): Pelobates fuscus insubricus: dis- tribuzione, biologia e conservazione di un taxon minacciato. Piano d’azione - Action Plan, Pro- getto LIFE-NATURA 1998 “Azioni urgenti per la conservazione di Pelobates fuscus insubricus*” B4-3200/98/486. WWF Italia, Roma. Andreone, F. (2006): Pelobate fosco / Spadefoot toad. In: Atlante degli Anfibi e dei Rettili d’Italia, pp. 292-297. Sindaco, R., Doria, G., Razzetti, E., Bernini, F., Eds., Edizioni Polistampa, Firenze. Andreone, F., Eusebio Bergò, P., Bovero, S., Gazzaniga, E. (2004): On the edge of extinction? The spadefoot Pelobates fuscus insubricus in the Po Plain, and a glimpse at its conservation biology. Ital. J. Zool. 71: 61-72. Andreone, F., Fortina, R., Chiminello, A. (1993): Natu- ral history, ecology and conservation of the Italian spadefoot toad, Pelobates fuscus insubricus, Scientific Reports. Società Zoologica “La Torbiera”, Novara. Andreone, F., Gentilli A., Scali S. (2007): Pelobates fus- cus (Laurenti, 1768). In: Fauna d’Italia. Amphibia, pp. 352-362. Lanza B., Andreone F., Bologna M.A., Corti C., Razzetti E., Eds, Calderini, Bologna. Andreone, F., Piazza, R. (1990): A bioacoustic study on Pelobates fuscus insubricus (Amphibia, Pelobatidae). Ital. J. Zool. 57: 341-349. Andreone, F., Sindaco, R., (1999): Erpetologia del Pie- monte e della Valle d’Aosta – Atlante degli Anfibi e dei Rettili. Monografie XXVI (1998), Museo Region- ale di Scienze Naturali, Torino. Berglund, B. (1998): Projekt Lökgroda 1993-1996. Läns- styrelsen i Skane län, Malmö, Sweden. Bosman, W., Van Den Munckhof, P. (2006): Terrestrial habitat use of the common spadefoot (Pelobates fus- cus) in an agricultural environment and an old sand- dune landscape. In: Herpetologia Bonnensis II. Pro- ceedings of the 13th Congress of the Societas Euro- paea Herpetologica, pp. 23-25. Vences, M., Kohler, J., Ziegler, T., Bohme, W., Eds, Societas Europaea Herpe- tologica, Bonn. Casale, A., Giachino, P.M., Allegro, G., Della Beffa, G., Picco, F. (1993): Comunità di Carabidae (Coleoptera) in pioppeti del Piemonte meridionale. Riv. Piem. St. Nat., 14: 149-170. Crottini A., Andreone F., Kosuch J., Borkin L.J., Litvin- chuk S.N., Eggert C., Veith M. (2007): Fossorial but widespread: the phylogeography of the common spa- defoot toad (Pelobates fuscus), and the role of the Po Valley as a major source of genetic variability. Mol. Ecol. 16: 1-21. Dubois, A. (1998): Mapping European amphibians and reptiles: collective inquiry and scientific methodology. Alytes 15: 176-204. Eggert, C. (2002): Use of fluorescent pigments and implantable transmitters to track a fossorial toad (Pelobates fuscus). Herpetol. J. 12: 69-74. Federici, S., Clemenzi, S., Favelli, M., Tessa, G., Andreone, F., Casiraghi, M., Crottini, A. (2008): Iden- tification of the pathogen Batrachochytrium dendroba- tidis in amphibian populations of a plain area in the Northwest of Italy. Herpetol. Notes 1: 33-37. Ferri, V. (2002): Monitoraggio dello status della popolazi- one di Pelobates fuscus insubricus del Parco Naturale della Valle del Ticino Piemonte. Rendiconto 2000-2001. Pelobates project in the Ticino Valley Natural Park of Piedmont LIFE00 NAT/IT/007233. Cameri (NO). Fog, K., Schmedes, A., Rosenørn de Lasson, D. (1997): The amphibians and reptiles of the Nordic countries. G. E. C. Gads Forlag, Copenhagen. Fortina, R., Andreone, F. (1999): Pelobates fuscus insubri- cus Cornalia, 1873 - Pelobate fosco italiano. In: Erpet- ologia del Piemonte e della Valle d’Aosta. Atlante degli Anfibi e dei Rettili, pp. 170-171. Andreone, F., Sin- daco, R., Eds, Museo Regionale di Scienze Naturali, Torino, Monografie XXVI (1998). Fortina, R., Quirino, M., Giachino, C., Pegolo, R. (2000): Le iniziative del WWF per la tutela del Pelobate insubrico (Pelobates fuscus insubricus) in Piemonte. In: Atti I Congresso Nazionale della Societas Herpe- tologica Italica, pp. 703-706. Giacoma, C., Ed, Museo Regionale di Scienze naturali, Torino. Gentilli, A., Scali, S. (2001): Ritmi di attività e scelte dell’habitat in Pelobates fuscus insubricus nell’alta pia- nura lombarda. Pianura 13: 313-316. Gislen, T., Kauri, H. (1959): Zoogeography of the Swedish amphibians and reptiles with notes on their growth and ecology. Acta Vert. 1: 195-398. Hels, T., Buchwald, E. (2001): The effect of road kills on amphibian populations. Conserv. Biol. 99: 331-340. Héron-Royer, L. F. (1888): Description du Pelobates latifrons des environs de Turin. B. Soc. Zool. Fr. 13: 85-91. Lanza, B. (1983): Anfibi e rettili. Guide per il riconosci- mento delle specie animali delle acque interne itali- 59Habitat selection in Pelobates fuscus insubricus ane. 27. Anfibi, Rettili (Amphibia, Reptilia). Consiglio Nazionale delle Ricerche, Roma. Lescure, J. (1984): La répartition passée et actuelle des Pelobates (Amphibiens, Anoures) en France. Bull. Soc. Herp. Fr. 29: 45-59. Mazerolle, M.J. (2006): Improving data analysis in herpe- tology: using Akaike’s Information Criterion (AIC) to assess the strength of biological hypotheses. Amphib- ia-Reptilia 27: 169-180. Mazzotti, S., Penazzi, R., Lizzio, L. (2002): Nuove segnal- azioni di Pelobates fuscus insubricus Cornalia 1873 nel sistema dei biotopi costieri del Ravennate. Quad. St. Not. St. Nat. Romagna 17: 91-97. Mercurio, V., Li Vigni, F. (2007): Rediscovery of Pelobates fuscus insubricus in the Asti Province, north-western Italy. Acta Herpetol. 2: 1-6. Nöllert, A., Nöllert, C. (1992): Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stutt- gart. Nyström, P., Birkedal, L., Dahlberg, C., Bronmark, C. (2002): The declining spadefoot toad Pelobates fuscus: calling site choice and conservation. Ecography 25: 488-498. Parent, G.H. (1985): Précisions sur la répartition du Pélobate brun, Pelobates fuscus (Laurenti, 1768), en France. Alytes 4: 52-60. Pelt, F.L., Van Bree, P.J.H. (1965): Enkele aantekeningen over de knoflookpad, Pelobates fuscus (Laurenti, 1768) in Nederland. Overdr. Nat. Hist. Maandbl. 54: 58-65. Perczy, C. (1994): Le site à Pelobates de la region Wal- lonne. Les cahiers des Reserves Naturelles - RNOB 7: 105–108. R Development Core Team (2010): R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http:// www.R-project.org/. Rappè, G. (1982): Nieuwe gegevens over het voorkomen van Pelobates fuscus (Laurenti) (Anura, Pelobatidae) in Belgie. Biol. Jb. Dodonaea 50: 255-259. Rondinini, C., Battistoni, A., Peronace, V., Teofili, C. (2013): Lista rossa IUCN dei Vertebrati italiani. Com- itato Italiano IUCN e Ministero dell’Ambiente e della Tutela del Mare, Roma. Scali, S., Gentilli, A. (2003): Biology aspects in a popu- lation of Pelobates fuscus insubricus Cornalia, 1873 (Anura: Pelobatidae). Herpetozoa 16: 51-60. Scali, S., Gentilli, A., Barbieri, E., Bernini, F., Vercesi, A. (2001): Un progetto integrato per la conservazione degli anfibi in Lombardia. Pianura 13: 121-123. Sindaco, R., Savoldelli, P., Selvaggi, A. (2009): La Rete Natura 2000 in Piemonte - I Siti di Importanza Comunitaria. Regione Piemonte, Torino. Sindaco, R., Vallinotto, E., Seglie, D. (2013): Pelobates fus- cus: esperienze pluriennali di gestione attiva. In: Atti IX Congresso Nazionale della Societas Herpetologica Italica, pp. 309-313. Scillitani, G., Liuzzi, C., Lorusso, L., Mastropasqua, F., Ventrella, P., Eds., Pineta, Con- versano. Strijbosch, H. (1979): Habitat selection of amphibians during their aquatic phase. Oikos 33: 363-372. SUPPLEMENTARY MATERIAL Table T1. Pearson correlation matrix (rp) among soil and land-use variables measured by the GIS in the 220 plots (70 with Spadefoot toad and 150 randomly selected). Acta Herpetologica Vol. 9, n. 1 - June 2014 Firenze University Press New cranial characters in the tribe Hydropsini (Serpentes: Dipsadidae: Xenodontinae) Diego O. Di Pietro1,*, Leandro Alcalde1,2, Jorge D. Williams1 The tadpole of Odontophrynus barrioi Cei, Ruiz, and Beçak, 1982 (Anura: Odontophrynidae): a comparison with the other tadpoles of the genus Exequiel González1, Guillermina Galvani1, Eduardo Sanabria2,*, Diego A. Barrasso3, Leandro Alcalde4, Lorena Quiroga1 High levels of prevalence related to age and body condition: host-parasite interactions in a water frog Pelophylax kl. hispanicus Mar Comas1, Alexis Ribas2,*, Concetta Milazzo3, Emilio Sperone3, Sandro Tripepi3 Microclimatic variation in multiple Salamandra algira populations along an altitudinal gradient: phenology and reproductive strategies Daniel Escoriza ¹, Jihene Ben Hassine² Fire salamander (Salamandra salamandra) in Larzac plateau: low occurrence, pond-breeding and cohabitation of larvae with paedomorphic palmate newts (Lissotriton helveticus) Mathieu Denoël*, Laurane Winandy Habitat selection in a fossorial toad Pelobates fuscus insubricus (Amphibia: Pelobatidae): does the soil affect species occurrence? Loredana Carisio1, Roberto Sacchi2, Daniele Seglie3, Roberto Sindaco4,* A new, recently extinct subspecies of the Kuroiwa’s Leopard Gecko, Goniurosaurus kuroiwae (Squamata: Eublepharidae), from Yoronjima Island of the Ryukyu Archipelago, Japan Yasuyuki Nakamura1, Akio Takahashi2, Hidetoshi Ota3 First evidence of the effects of agricultural activities on gonadal form and function in Rhinella fernandezae and Dendropsophus sanborni (Amphibia: Anura) from Entre Ríos Province, Argentina Laura C. Sanchez1,*, Rafael C. Lajmanovich1, Paola M. Peltzer1, Adriana S. Manzano2, Celina M. Junges1, Andrés M. Attademo1 A review of the genus Gonionotophis in north-eastern Africa (Squamata: Lamprophiidae) Benedetto Lanza1, Donald G. Broadley2 Observations on the use of tarantula burrows by the anurans Leptodactylus bufonius (Leptodactylidae) and Rhinella major (Bufonidae) in the Dry Chaco ecoregion of Bolivia Christopher M. Schalk1, Marco Sezano2 A preliminary report of amphibian mortality patterns on railways Karolina A. Budzik1, Krystian M. Budzik2 Meiotic behavior of two polyploid species of genus Pleurodema (Anura: Leiuperidae) from central Argentina Nancy E. Salas1, Julián A. Valetti2, Pablo R. Grenat1,3,*, Manuel A. Otero1, Adolfo L. Martino1 Clutch size in wild populations of Alytes muletensis Samuel Pinya1,*, Valentín Pérez-Mellado2 Consequences of haemogregarine infection on the escape distance in the lacertid lizard, Podarcis vaucheri Isabel Damas-Moreira1,2,*, D. James Harris1, Daniela Rosado1,2, Isabel Tavares1,2, João P. Maia1,2,3, Daniele Salvi1, Ana Perera1 Death in the clouds: ranavirus associated mortality in assemblage of cloud forest amphibians in Nicaragua Tariq Stark1,*, Carlijn Laurijssens¹, Martijn Weterings¹,², Annemarieke Spitzen-van der Sluijs³,4, An Martel4, Frank Pasmans4 Book Review: Federico Chacón, Richard Dennis Johnson. Amphibians and Reptiles of Costa Rica. Federico Chacón, Richard Dennis Johnson. Amphibians and Reptiles of Costa Rica. Anfibios y Reptiles de Costa Rica. Sebastiano Salvidio ACTA HERPETOLOGICA Journal of the Societas Herpetologica Italica