Species diversity and distribution of amphibians and reptiles in Sardinia, Italy

Although distribution databases are a dynamic tool, continuously updated, it is important to take "snapshots" of the species distribution over time to promptly identify potential conservation issues. With this work, we provide an update of the distribution of amphibians and reptiles in Sardinia and satellite islands. Data derive from both direct field observations (carried out since 2005 until July 2022) and literature, accounting for over 7000 records: 1416 records of 11 species of amphibians and 5600 records of 18 species of reptiles. Distribution maps (on 10 × 10 km UTM grid) of 29 species are provided in supplementary materials as well as the updated list of the amphibians and reptiles occurring in the circum-Sardinian islands. Most of the meshes were characterized by the presence of 1-3 amphibian species (73%) and 6-8 or 9-11 reptile species (32% with 6-8 species, 30% with 9-11 species). Species abundance was favoured by environmental heterogeneity, and mostly varied in relation to elevation range and edge density

Monitoraggio della biodiversità in relazione all'applicazione degli standard di condizionalità: 4.2c, 4.6, 4.3 (olivo)

Nel presente lavoro vengono riportati i risultati relativi ai monitoraggi della diversità faunistica per i seguenti standard: 4.2c, 4.3 (olivo), 4.6. I risultati ottenuti sono nel complesso interessanti sia dal punto di vista metodologico sia per quanto concerne gli aspetti conservazionistici e gestionali. Emerge l'importanza di utilizzare più indicatori o gruppi tassonomici che comprendano taxa ecologicamente e funzionalmente diversi per valutare la "biodiversità". Relativamente allo sfalcio è stato osservato che una "blanda gestione" dei ritirati dalla produzione può favorire un certo incremento di biodiversità sia per quanto riguarda gli Artropodi, sia per quanto riguarda i Rettili. Risultati concordi sono stati osservati anche negli oliveti dove la gestione della vegetazione al suolo (sfalcio) sembrerebbe incrementare la diversità. Tuttavia è opportuno ricordare che l'effetto monitorato, almeno nei ritirati dalla produzione, non è quello immediatamente successivo all'azione meccanica che invece provoca danni diretti e immediati alla fauna (ferimento e uccisione). Emerge con evidenza dai dati raccolti anche l'importanza della presenza, all'interno degli agro-ecosistemi, di aree a minor disturbo antropico, naturali e semi-naturali: fasce ecotonali e ripariali, ma anche bordure dei campi. Viceversa l'uniformità del paesaggio e la presenza di grandi estensioni coltivate a monocoltura rappresentano elementi sfavorevoli alla biodiversità animale. Nel monitoraggio attraverso l'utilizzo della tecnica di fototrappolaggio è emersa l'importante funzione svolta dai muretti a secco, "presenze" tipiche e diffuse nel paesaggio agricolo tradizionale del nostro territorio italiano. Per molti taxa animali detti manufatti assolvono a funzioni ecologiche diverse, quali: rifugio, aree di foraggiamento, passaggio o sosta nonché punti ottimali per la termoregolazione.</p

Ecological focus area – EFA: the biological value of olive groves. A case study in Sardinia (Italy)

Among the CAP (Common Agricultural Policy) 2015-2020 innovations, a mandatory ‘greening’ component of direct payment has been included to improve sustainable and environmentally friendly agricultural practices in arable lands. Permanent crops1 are considered as ‘greening’ by definition and therefore exempted from additional agronomic duties. So far, however, an adequate knowledge of the real biological value of permanent crops is still lacking. In the present work, realized in the context of the MO.NA.CO. project, we monitored animal diversity in olive-groves characterized by three different managements (from low to medium intensity). Monitoring was carried out in Sardinia (Italy), using different animal groups as bio-indicators: Arthropods, Reptiles and Birds. Considering Arthropod orders and Coleopteran families we did not found significant differences in the overall abundance and in the biodiversity indexes. However, faunal composition clearly varied among managements: moreover, the higher or lesser presence of certain taxa highlighted the existence of microenvironmental variables that may be related, for instance, to the level of soil vegetation cover or to the degree of naturalness of the agroecosystem. Limitedly to the Arthropod diversity, the comparison with other land uses (including data gathered in previous projects) showed a good potentiality of olive groves as ‘ecological focus areas’, at least considering the managements here examined. The monitoring of Reptiles and Birds showed the peculiarity of the olive groves located in a hilly area characterized by non-intensive management, which hosted a rich herpetofauna and a bird community typical of habitats characterized by a high degree of naturalness. The present monitoring provides data for the assessment of the biological value of olive groves and of the potential impact of different managements on faunistic diversity. Future monitoring is needed to improve the knowledge on olive tree plantations characterized by high intensive management

Ecological focus area – EFA: the biological value of olive groves. A case study in Sardinia (Italy)

Among the CAP (Common Agricultural Policy) 2015-2020 innovations, a mandatory ‘greening’ component of direct payment has been included to improve sustainable and environmentally friendly agricultural practices in arable lands. Permanent crops1 are considered as ‘greening’ by definition and therefore exempted from additional agronomic duties. So far, however, an adequate knowledge of the real biological value of permanent crops is still lacking. In the present work, realized in the context of the MO.NA.CO. project, we monitored animal diversity in olive-groves characterized by three different managements (from low to medium intensity). Monitoring was carried out in Sardinia (Italy), using different animal groups as bio-indicators: Arthropods, Reptiles and Birds. Considering Arthropod orders and Coleopteran families we did not found significant differences in the overall abundance and in the biodiversity indexes. However, faunal composition clearly varied among managements: moreover, the higher or lesser presence of certain taxa highlighted the existence of microenvironmental variables that may be related, for instance, to the level of soil vegetation cover or to the degree of naturalness of the agroecosystem. Limitedly to the Arthropod diversity, the comparison with other land uses (including data gathered in previous projects) showed a good potentiality of olive groves as ‘ecological focus areas’, at least considering the managements here examined. The monitoring of Reptiles and Birds showed the peculiarity of the olive groves located in a hilly area characterized by non-intensive management, which hosted a rich herpetofauna and a bird community typical of habitats characterized by a high degree of naturalness. The present monitoring provides data for the assessment of the biological value of olive groves and of the potential impact of different managements on faunistic diversity. Future monitoring is needed to improve the knowledge on olive tree plantations characterized by high intensive management

Assessing the Spatial Scale Effect of Anthropogenic Factors on Species Distribution

<div><p>Patch context is a way to describe the effect that the surroundings exert on a landscape patch. Despite anthropogenic context alteration may affect species distributions by reducing the accessibility to suitable patches, species distribution modelling have rarely accounted for its effects explicitly. We propose a general framework to statistically detect the occurrence and the extent of such a factor, by combining presence-only data, spatial distribution models and information-theoretic model selection procedures. After having established the spatial resolution of the analysis on the basis of the species characteristics, a measure of anthropogenic alteration that can be quantified at increasing distance from each patch has to be defined. Then the distribution of the species is modelled under competing hypotheses: H₀, assumes that the distribution is uninfluenced by the anthropogenic variables; H₁, assumes the effect of alteration at the species scale (resolution); and H₂, H₃ … H_n add the effect of context alteration at increasing radii. Models are compared using the Akaike Information Criterion to establish the best hypothesis, and consequently the occurrence (if any) and the spatial scale of the anthropogenic effect. As a study case we analysed the distribution data of two insular lizards (one endemic and one naturalised) using four alternative hypotheses: no alteration (H₀), alteration at the species scale (H₁), alteration at two context scales (H₂ and H₃). H₂ and H₃ performed better than H₀ and H₁, highlighting the importance of context alteration. H₂ performed better than H₃, setting the spatial scale of the context at 1 km. The two species respond differently to context alteration, the introduced lizard being more tolerant than the endemic one. The proposed approach supplies reliably and interpretable results, uses easily available data on species distribution, and allows the assessing of the spatial scale at which human disturbance produces the heaviest effects.</p> </div

BAM diagram.

<p>Simplified version of the Biotic-Abiotic-Movement diagram from Sauge et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067573#B16" target="_blank">16</a>]. “G” represents the geographic space. “B” is the part of G that presents the correct set of biotic conditions: in this simplified version B is assumed not to constrain species distribution [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067573#B3" target="_blank">3</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067573#B16" target="_blank">16</a>]. “A” is the part of G that holds suitable abiotic conditions. “M” represents the sub-area of G that has been accessible and explored by the species. The intersection between M and A defines the species distribution (G₀). G_I is the area that is potentially suitable, but has not been accessible to the species.</p

Variation partitioning diagrams for the H₂ hypothesis for the two species.

<p>Circles represent variation explained by each factor (climate and topography, alteration, patch context). Numbers correspond to the percentage of variation associated to each circle subpart (pure, two-factor intersection, three factors intersection). The percentage associated to intersecting areas has not to be interpreted as interaction, but as a variation indifferently assignable to one or more factors [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067573#B65" target="_blank">65</a>]. Values smaller than 0.01% are not shown.</p

Response curve for the anthropogenic variable of the best model (H₂).

<p>A: marginal response curves for the variable “alteration” (suitability is obtained from the full model keeping constant all the variables but alteration). B: single variable response curves for the same variable (suitability is obtained from a model including only the variable “alteration”). C: marginal response curves for PC-fine (patch context alteration). D: single variable response curves for the same variable. Solid lines indicate the mean of ten cross validated models; dashed lines represent the minimum and maximum range of the response curves.</p

Maps of the competing SDM.

<p>A, B, C, D represent the models under hypotheses respectively H₀, H₁, H₂ and H₃ for <i>P</i><i>. siculus</i>. E, F, G, H represent the same hypotheses for <i>P</i><i>. tiliguerta</i>. Occurrences are also shown in separate maps.</p