Citizen science data of cetaceans in the Arabian/Persian Gulf: Occurrence and habitat preferences of the three most reported species

Citizen science data are becoming increasingly relevant in wildlife studies, especially when obtaining data requires costly logistics. In the Arabian/Persian Gulf, baseline information about cetaceans is scarce despite their regular presence. From 2012 to 2019, a citizen science campaign conducted in the United Arab Emirates (UAE) obtained information on 1,292 cetacean sightings. These were methodically validated by experts, resulting in 1,103 records where species was confidently assigned. From the 12 species reported, we analyzed the spatial patterns of occurrence and drivers of habitat preference for the three most reported species: Tursiops aduncus (Ta 53%), Sousa plumbea (Sp 45%), and Neophocaena phocaenoides (Np 2%). Ecological niche modelling, considering seven environmental variables (physicochemical: temperature, silicate, calcite, pH; physiographic: distance from coast, bathymetry; biological: chlorophyll) showed subtle niche partitioning among the three species. Our results suggest different diets and energy requirements for Np, with Ta and Sp, segregating mostly by different patterns of space use. Specifically, Sp prefers close proximity to shore, particularly areas with complex networks of inland canals. This information provides an estimate of habitat preferences, that can be used in formulating effective conservation measures. Sp shows the narrowest area of suitable habitat and is at particular risk from habitat degradation

Free GIS for herpetologists: free data sources on Internet and comparison analysis of proprietary and free/open source software

Geographical Information Systems (GIS) have been used widely in zoology and ecology, particularly in herpetology. The use of spatially explicit analysis has increased during the last decade, with the consequent expansion of GIS application in ecology. During the last years, geo-information technology has been developed within the Free/Open Source Software (FOSS) community, resulting in new open source formats and several GIS packages. However, proprietary packages seem still to be the first choice for herpetologists, thus involving non negligible costs for GIS technology adoption. Additional costs arise from environmental data, which are usually expensive, worsening in the case of large study areas. An alternative solution is to use freely available data, despite a possible decrease of resolution. In this review, we aim to show the feasibility of spatial analysis within FOSS GIS packages, rank these packages using the number of available tools and list several data sources freely available on the Internet. We listed several websites providing the most important free data for spatial analysis, i.e. altitude and derived data; past, current and future climatic series data; and satellite derived data. We provide also a list of the most commonly used functions in GIS analysis and their availability in the six software compared in this study (ArcGIS; gvSIG; ILWIS; Quantum GIS; GRASS; and DIVA-GIS). The software gvSIG is the one with more functions (106) followed by Quantum GIS with 94 and GRASS with 84

Distribution modelling of an introduced species: do adaptive genetic markers affect potential range?

Biological invasions have increased in the last few decades mostly due to anthropogenic causes such as globalization of trade. Because invaders sometimes cause large economic losses and ecological disturbances, estimating their origin and potential geographical ranges is useful. Drosophila subobscura is native to the Old World but was introduced in the New World in the late 1970s and spread widely. We incorporate information on adaptive genetic markers into ecological niche modelling and then estimate the most probable geographical source of colonizers; evaluate whether the genetic bottleneck experienced by founders affects their potential distribution; and finally test whether this species has spread to all its potential suitable habitats worldwide. We find the environmental space occupied by this species in its native and introduced distributions are notably the same, although the introduced niche has shifted slightly towards higher temperature and lower precipitation. The genetic bottleneck of founding individuals was a key factor limiting the spread of this introduced species. We also find that regions in the Mediterranean and north-central Portugal show the highest probability of being the origin of the colonizers. Using genetically informed environmental niche modelling can enhance our understanding of the initial colonization and spread of invasive species, and also elucidate potential areas of future expansions worldwide

Estimating home-range size: when to include a third dimension?

Most studies dealing with home ranges consider the study areas as if they were totally flat, working only in two dimensions, when in reality they are irregular surfaces displayed in three dimensions. By disregarding the third dimension (i.e., topography), the size of home ranges underestimates the surface actually occupied by the animal, potentially leading to misinterpretations of the animals' ecological needs. We explored the influence of considering the third dimension in the estimation of home-range size by modeling the variation between the planimetric and topographic estimates at several spatial scales. Our results revealed that planimetric approaches underestimate home-range size estimations, which range from nearly zero up to 22%. The difference between planimetric and topographic estimates of home-ranges sizes produced highly robust models using the average slope as the sole independent factor. Moreover, our models suggest that planimetric estimates in areas with an average slope of 16.3° (±0.4) or more will incur in errors ≥5%. Alternatively, the altitudinal range can be used as an indicator of the need to include topography in home-range estimates. Our results confirmed that home-range estimates could be significantly biased when topography is disregarded. We suggest that study areas where home-range studies will be performed should firstly be scoped for its altitudinal range, which can serve as an indicator for the need for posterior use of average slope values to model the surface area used and/or available for the studied animals.This work was partially supported by a research project from the Spanish National Plan (project ref: CGL2009-10741) funded by the Spanish Ministry of Science and Innovation and EU-FEDER funds. P. M. was supported by a Ph.D. grant from the Fundaçao para a Ciència e a Tecnologia (FCT) (SFRH/BD/37795/2007). N. S. was partially supported by a postdoctoral grant from FCT (SFRH/BPD/26666/2006). L. M. R. was funded by a Postdoctoral fellowship from the FCT and Fundo Social Europeu (III Quadro Comunitario de Apoio) (SFRH/BPD/35842/2007) and FAPESP (Proc. Ref.: 2011/00408-4).Peer Reviewe

Using citizen science in road surveys for large-scale amphibian monitoring: are biased data representative for species distribution?

Abstract: Road-based citizen science surveys are increasingly used for long-term monitoring of wildlife, including amphibians, over large spatial scales. However, how representative such data are when compared to the actual species distribution remains unclear. Spatial biases in site selection or road network coverage by volunteers could skew results towards more urbanised areas and consequently produce incorrect or partial trend estimations at regional or national scales. Our objective was to compare and verify potential spatial biases of road-based data using distribution datasets of different origins. We used as a case study the common toad (Bufo bufo), a fast-declining species and the main amphibian targeted by conservation action on roads in Europe. We used Maxent models to compare road survey data obtained from the 35 year-long “Toads on Roads” project in Great Britain with models using national-scale toad distribution records as well as with models using randomly generated points on roads. Distribution models that used data collected by volunteers on roads produced similar results to those obtained from overall species distribution, indicating the lack of selection bias and high spatial coverage of volunteer-collected data on roads. Toads were generally absent from mountainous areas and, despite the high availability of potential recorders, showed nearly complete absence of road-based records in large urban areas. This is probably the first study that comparatively evaluates species distribution models created using datasets of different origin in order to verify the influence of potential spatial bias of data collected by volunteers on roads. Large-scale declines of widespread amphibians have been demonstrated using data collected on roads and our results indicate that such data are representative and certainly comparable to other existing datasets. We show that for countries with high road network coverage, such as Great Britain, road-based data collected by volunteers represent a robust dataset and a critical citizen science contribution to conservation

Local segregation of realised niches in lizards

Species can occupy different realised niches when sharing the space with other congeneric species or when living in allopatry. Ecological niche models are powerful tools to analyse species niches and their changes over time and space. Analysing how species’ realised niches shift is paramount in ecology. Here, we examine the ecological realised niche of three species of wall lizards in six study areas: three areas where each species occurs alone; and three areas where they occur together in pairs. We compared the species’ realised niches and how they vary depending on species’ coexistence, by quantifying niche overlap between pairs of species or populations with the R package ecospat. For this, we considered three environmental variables (temperature, humidity, and wind speed) recorded at each lizard re-sighting location. Realised niches were very similar when comparing syntopic species occurring in the same study area. However, realised niches differed when comparing conspecific populations across areas. In each of the three areas of syntopy, the less abundant species shift its realised niche. Our study demonstrates that sympatry may shift species’ realised niche

Fully automatic multi-temporal land cover classification using Sentinel-2 image data

[Abstract] The analysis of remote sensing images represents a highly important issue to be performed in many relevant fields such as climate change studies or land cover mapping. Traditional proposals usually identify the land cover classes from general related groups such as different tree species or different crop varieties. Additionally, these proposals commonly use information from a precise time span or season, not accounting for the variability of the data over the entire year, specially in regions with several seasons. In this work, we propose a multi-temporal classification system to identify and represent diverse land cover classes over any period of the entire year by using Sentinel-2 satellite image data. To this end, 526 representative samples were labelled from 5 complex and variable different land cover types over the Special Area of Conservation (SAC) Betanzos-Mandeo in the northwest of the Iberian Peninsula. The method achieves a satisfactory mean accuracy value of 84.0% for the testing set using the best configuration with a radial Support Vector Machine classifier. This system will be used in the study of the population connectivity of two threatened herptiles, but it can be easily extended to other species of interest in the future.Xunta de Galicia; ED431G/01Xunta de Galicia; ED431C 2016-04

Where to look when identifying roadkilled amphibians?

Roads have multiple effects on wildlife; amphibians are one of the groups more intensely affected by roadkills. Monitoring roadkills is expensive and time consuming. Automated mapping systems for detecting roadkills, based on robotic computer vision techniques, are largely necessary. Amphibians can be recognised by a set of features as shape, size, colouration, habitat and location. This species identification by using multiple features at the same time is known as “jizz”. In a similar way to human vision, computer vision algorithms must incorporate a prioritisation process when analysing the objects in an image. Our main goal here was to give a numerical priority sequence of particular characteristics of roadkilled amphibians to improve the computing and learning process of algorithms. We asked hundred and five amateur and professional herpetologists to answer a simple test of five sets with ten images each of roadkilled amphibians, in order to determine which body parts or characteristics (body form, colour, and other patterns) are used to identify correctly the species. Anura was the group most easily identified when it was roadkilled and Caudata was the most difficult. The lower the taxonomic level of amphibian, the higher the difficulty of identifying them, both in Anura and Caudata. Roadkilled amphibians in general and Anura group were mostly identified by the Form, by the combination of Form and Colour, and finally by Colour. Caudata was identified mainly on Form and Colour and on Colour. Computer vision algorithms must incorporate these combinations of features, avoiding to work exclusively in one specific feature.Special thanks to all respondents (Suppl. Mat. Appendix A3-Contributors / Respondents) and to all who have contributed to diffusion and promotion of the Roadkills survey: Road Ecology Group on Facebook, Asociación Herpetológica Granadina, Asociación Herpetológica Española (AHE), Herpnet and all individuals who have also believed appropriate the disclosure of the survey. Thanks to an anonymous reviewer for English linguistic advising and for the comments and suggestions that greatly improved the last version of the manuscript. M. Franch and C. Silva are funded by a grant (UMINHO/ BI/175/2013, UMINHO/BI/172/2013) (from the Foundation for Science and Technology Portugal (FCT) and cofinanced by FEDER through COMPETE –POFC (“Intelligent systems for mapping amphibian mortality on Portuguese roads”, PTDC/BIA-BIC/4296/2012). N. Sillero is supported by an FCT contract IF/01526/2013.info:eu-repo/semantics/publishedVersio

High resolution trichromatic road surface scanning with a line scan camera and light emitting diode lighting for road-kill detection

This paper presents a road surface scanning system that operates with a trichromatic line scan camera with light emitting diode (LED) lighting achieving road surface resolution under a millimeter. It was part of a project named Roadkills-Intelligent systems for surveying mortality of amphibians in Portuguese roads, sponsored by the Portuguese Science and Technology Foundation. A trailer was developed in order to accommodate the complete system with standalone power generation, computer image capture and recording, controlled lighting to operate day or night without disturbance, incremental encoder with 5000 pulses per revolution attached to one of the trailer wheels, under a meter Global Positioning System (GPS) localization, easy to utilize with any vehicle with a trailer towing system and focused on a complete low cost solution. The paper describes the system architecture of the developed prototype, its calibration procedure, the performed experimentation and some obtained results, along with a discussion and comparison with existing systems. Sustained operating trailer speeds of up to 30 km/h are achievable without loss of quality at 4096 pixels' image width (1 m width of road surface) with 250 µm/pixel resolution. Higher scanning speeds can be achieved by lowering the image resolution (120 km/h with 1 mm/pixel). Computer vision algorithms are under development to operate on the captured images in order to automatically detect road-kills of amphibians.This work was financed by FEDER Funds, through the Operational Programme for Competitiveness Factors-COMPETE, and by National Funds through FCT-Foundation for Science and Technology of Portugal, under the project PTDC/BIA-BIC/4296/2012 with the name-Roadkills: Intelligent systems for mapping amphibian mortality on Portuguese roads. C.S. and M.F. are supported by Research Grants contracts by FCT (UMINHO/BI/172/2013 and UMINHO/BI/175/2013 respectively). N.S. is supported by an IF (Investigador FCT) contract by FCT (IF/01526/2013). The authors also wish to thank the entities involved, in particular, School of Engineering of the University of Minho and the Algoritmi research center, the Faculty of Sciences of the University of Porto and the University Institute of Maia.info:eu-repo/semantics/publishedVersio

Predicting Cetacean Distributions in the Eastern North Atlantic to Support Marine Management

Acknowledgments We thank all the volunteers for their contribution and dedication during the monitoring campaigns. This manscript is a product of the work of every observer who participated in the CETUS Project. We are extremely grateful to TRANSINSULAR, the cargo ship company that provided all the logistic support, and to the ships’ crews for their hospitality. We also thank Vasilis Valavanis for his valuable advice about the use of oceanographic variables.Peer reviewedPublisher PD