Using species distribution models at local scale to guide the search of poorly known species: Review, methodological issues and future directions

Among specific applications of species distribution models (SDMs), the use of SDMs probabilistic maps for guiding field surveys is increasingly applied. This approach is particularly used for poorly known and/or cryptic species in order to better assess their distribution. One of the most interesting aspects of these applications is that predictions could be clearly validated by real data, subsequently obtained in the field. Despite this important difference from other applications, to our knowledge, the efficiency of different algorithms, metrics for model evaluation and algorithm-specific settings have not yet been sufficiently investigated. This research performs a literature survey to investigate which species, study area characteristics, variables, techniques and settings were used or suggested by previous authors. We then applied the most common approaches to guide field surveys for a set of 70 vascular plants in an endemic-rich area of Sardinia (Italy) of approx. 9000 ha, the flora of which was deeply investigated during the last two years. Our main aims were: (1) to use pre-model records for predicting the potential occurrence of plant species with different sample size, detectability and habitat preference, (2) to apply results for guiding searches for new populations of poorly known species, (3) to calculate the model performance according to independent real presence/absence data (testAUC) and (4) to compare different modelling data input and settings on the testAUC basis. By emphasizing the importance of field verification, both the review and the worked example supported the reliability of SDMs for a wide range of species to understand where a species could potentially be present and therefore to optimise resources for the search of new species localities. This study may help understand and summarise the most applied methodological approaches and to highlight future directions for this practical application. Without underrating the importance of most common recommendations, practitioners are encouraged to test the ability of this SDMs’ application with their own data. Indeed, large gaps in biological groups (e.g. insects) and in regions covered by these kind of studies (e.g. many African and Asian territories) were found. Furthermore, eventual biases due to lack of data, experience or staff, have in this experimental case less irreparable consequences than others, such as conservation assessments based on future projections, which cannot be otherwise adjusted by explicit data from ground validation

Carignan Grape Cultivar Salt Tolerance during the Germination Phase across the Mediterranean Basin

Carignan is a black grape cultivar widely planted throughout the western Mediterranean Basin. The grape faces significant viticultural hazards such as soil salinization, which affects about 6% of the world’s total land area. The search for salt tolerance genotypes to be introduced in crossbreeding programs and obtaining new cultivars is a key factor. The seed germination and salt tolerance of Carignan were studied from different coastal vineyards across the Mediterranean Basin, and as well as whether the distance from the sea affected germination and salt tolerance. Carignan seeds, independently of the temperature and distance from the sea, germinated more than 50% under 125 mM NaCl concentrations. Seed recovery was elevated, including the capacity of gemination after high salt exposure (500 mM NaCl). The results on germination behavior related to the distance from the sea showed that all tested vineyards, except for the one farthest from the sea, had similar germination responses. The optimum germination condition to select salt-tolerant accessions is alternating temperatures 25/10 °C and 125 mM NaCl. Thanks to the ability of the Carignan to germinate in a saline substrate and their capacity for recovery, it could be useful to crossbreeding programs, for integrating as rootstock selection or for the improvement of cultivars through sexual reproduction

Domestic grape germination behaviour: the ‘Chardonnay’ and ‘Syrah’international cultivars’s study case

The domestic grape germination eco-physiology is a little studied aspect since reproduction occurs predominantly agamically, despite the sexual reproduction remains the main form for the selection of new cultivars. In this study, two international cultivars grown all over the world-Chardonnay and Syrah-were chosen as models of the domestic grape for the experiments in the eco-physiology of germination. The experimental design consisted of chemical, mechanical pre-treatments and combination of them as the bird ingestion pre-treatment that simulates the transit through the digestive tract of birds. Furthermore, seeds were submitted to different periods of cold stratification -0, 15, 30, 60 and 90 days -to simulate the winter effect. Seeds were placed to germinate at different incubation temperatures, to find the optimal germination protocol. The results showed that domestic grapes retain the need for cold stratification, and the best germination temperature is represented by the fluctuating temperature that simulates spring conditions. Our results help to understand what the best germination conditions of domestic grapes are and offer a contribution to extend the knowledge on how the process of domestication may have affected the biology of Vitis vinifera L. subsp. vinifera

Notulae to the Italian alien vascular flora: 12

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. material

Does Storage under Gene Bank Conditions Affect Seed Germination and Seedling Growth? The Case of Senecio morisii (Asteraceae), a Vascular Plant Exclusive to Sardinian Water Meadows

Understanding seed viability under long-term storage conditions provides basic and useful information to investigate the eectiveness of seed banking. Besides the germination success, seedling establishment is also an important requirement, and a decisive step to ensure plant propagation. We used comparative data of germination, seedling growth, and survival percentage between fresh and 10-years-stored seeds of Senecio morisii, a narrow endemic and vulnerable species of Sardinia (Italy), in order to evaluate if differences exist in these traits between fresh and 10-years-stored seeds. Stored seeds showed higher germination percentages than fresh ones, whereas seedling growth and survival did not present significant differences between them, except for seedling growth in plants produced from seeds germinated at 25 °C. This study allowed us to assess if seeds of S. morisii were able to germinate under controlled conditions, and if they maintained their viability and germination capacity for at least 10 years of long-term storage in the seed bank. In addition, the high seedling survival detected in both fresh and stored seeds suggests that stored seeds of S. morisii can be used to support reinforcement or reintroduction actions when fresh materials are not available

Predicting the consequences of global warming on Gentiana lutea germination at the edge of its distributional and ecological range

Background: Temperature is the main environmental factor controlling seed germination; it determines both the percentage and the rate of germination. According to the Intergovernmental Panel on Climate Change, the global mean surface temperature could increase of approximately 2–4 °C by 2090–2099. As a consequence of global warming, the period of snow cover is decreasing on several mountain areas. Thermal time approach can be used to characterise the seed germination of plants and to evaluate the germination behaviour under the climate change scenarios. In this study, the effect of different cold stratification periods on seed dormancy release and germination of Gentiana lutea subsp. lutea, a taxon listed in Annex V of the Habitats Directive (92/43/EEC), was evaluated. Furthermore, the thermal requirements and the consequences of the temperature rise for seed germination of this species were estimated. In addition, a conceptual representation of the thermal time approach is presented. Methods: Seeds of G. lutea subsp. lutea were harvested from at least 50 randomly selected plants in two representative localities of the Gennargentu massif (Sardinia). Germination tests were carried out under laboratory conditions and the responses at 5, 10, 15, 20, 25 and 30 °C were recorded. Different cold stratification pre-treatments at 1 ± 1 C (i.e. 0, 15, 30, 60 and 90 days) were applied. Successively, the base temperature (Tb) and the number of thermal units (θ, °Cd) for germination were estimated. Additionally, this study examined the consequences of an increase in temperatures based on the Representative Concentration Pathways (RPC) scenarios. Results: The results indicated that from 0 to 30 days of cold stratification, the germination was null or very low. After 60 and 90 days of cold stratification the seed dormancy was removed; however, 25 and 30 °C negatively affected the germination capacity of non-dormant seeds. Seeds cold-stratified for 90 days showed a lower Tb than those stratified for 60 days. However, 60 and 90 days of cold stratification did not cause great variations in the thermal time units. Analysing the RPC scenarios, we detected that the number of days useful for dormancy release of seeds of G. lutea may be less than 30 days, a condition that does not permit an effective dormancy release.Conclusions: We conclude that seeds of G. lutea need at least 60 days of cold stratification to remove dormancy and promote the germination. The thermal time model developed in this work allowed us to identify the thermal threshold requirements of seed germination of this species, increasing the knowledge of a plant threatened by global warming. Our results emphasise the need for further studies aiming at a better characterisation of germination efficiency, especially for species that require cold stratification. This would improve the knowledge on the germination mechanisms of adaptation to different future global warming conditions

The impact of climatic variations on the reproductive success of Gentiana lutea L. in a Mediterranean mountain area

Increases in temperature have been predicted and reported for the Mediterranean mountain ranges due to global warming and this phenomenon is expected to have profound consequences on biodiversity and ecosystem functioning. We hereby present the case of Gentiana lutea L. subsp. lutea, a rhizomatous long-lived plant living in Central-Southern Europe, which is at the edge of its ecological and distributional range in Sardinia. Concretely, we analysed the reproductive success experienced during three phenological cycles (2013/2014, 2014/2015 and 2015/2016) in four representative populations, with particular attention to the phenological cycle of 2014/2015, which has been recorded as one of the warmest periods of the last decades. The Smirnov-Grubbs test was used to evaluate differences in temperature and precipitation regimes among historical data and the analysed years, while the Kruskal-Wallis followed by the Wilcoxon test was used to measure differences between anthesis and reproductive performances among cycles and populations. In addition, generalised linear models were carried out to check relationships between climate variables and reproductive performance. Significant differences among climate variables and analysed cycles were highlighted, especially for maximum and mean temperatures. Such variations determined a non-flowering stage in two of the four analysed populations in 2014/2015 and significant differences of further five reproductive traits among cycles. These results confirmed that in current unstable climatic conditions, which are particularly evident in seasonal climates, reproductive success can be a sensitive and easily observable indicator of climatic anomalies. Considering the importance of this issue and the ease and cost-effectiveness of reproductive success monitoring, we argue that research in this sense can be a supporting tool for the enhancement of future crucial targets such as biodiversity conservation and the mitigation of global warming effects

The MedIsWet project in Sicily and Sardinia. An opportunity for improving wetland knowledge and conservation. Preliminary results

The MedIsWet (Mediterranean Island Wetlands) project is responding to the Ramsar Resolution XII.14 aiming for the conservation of Mediterranean Basin islands wetlands. The project is funded by the MAVA “Foundation pour la Nature”. MedIsWet contributes to the implementation of a network of nine Mediterranean countries involved in the completion of the inventories of all the Mediterranean islands wetlands, dissemination of knowledge and promotion of certain conservation measures at local, national and Mediterranean scale. Within the MedIsWet partnership, the University of Catania (Sicily) and the University of Cagliari (Sardinia) are adhering to the initiative by implementing the project for a large representative set of Mediterranean island wetlands. As far as Sicily is concerned, the ongoing investigation, based on GIS tools and field trips has allowed us to catalog over 11,400 wetlands of various sizes, from around 1000 square meters to several hectares. Most of the natural wetlands fall into protected areas such as Natura 2000 sites and parks, while artificial ones are mostly related to unprotected agricultural lands. The same pattern, for the identified 2500 wetlands, was found in Sardinia. With respect to previous knowledge, numbers are surprisingly very big, the highest for the Mediterranean Islands. Such a high number is due to the underestimation of small basins and artificial tanks connected with agricultural practices. Many of them are relatively recent, being excavated in the last twenty-thirty years thanks to the support of European funds for agriculture; nonetheless, there is also a large set of seminatural wetlands of different sizes and in different edaphoclimatic conditions, which have been created since the Iron Age up to more recent periods. While a great deal of data was found on the vegetation of natural coastal and inland wetlands, very few was instead recorded for the artificial ones. Field surveys on a robust sample of artificial basins and all natural or semi-natural areas are going to fill the existing knowledge gap and to identify the vegetation types, habitats and their conservation status. First results indicated that efforts in including the underrated set of artificial and semi-natural wetlands will allow to re-evaluate these areas as possible ecological corridors and, sometimes, as important sites for plant diversity