Ryan Rash

Citizen science initiatives have been increasingly used by researchers as a source of occurrence data to model the distribution of alien species. Since citizen science presence‐only data suffer from some fundamental issues, efforts have been made to combine these data with those provided by scientifically structured surveys. Surprisingly, only a few studies proposing data integration evaluated the contribution of this process to the effective sampling of species' environmental niches and, consequently, its effect on model predictions on new time intervals. We relied on niche overlap analyses, machine learning classification algorithms and ecological niche models to compare the ability of data from citizen science and scientific surveys, along with their integration, in capturing the realized niche of 13 invasive alien species in Italy. Moreover, we assessed differences in current and future invasion risk predicted by each data set under multiple global change scenarios. We showed that data from citizen science and scientific surveys captured similar species niches though highlighting exclusive portions associated with clearly identifiable environmental conditions. In terrestrial species, citizen science data granted the highest gain in environmental space to the pooled niches, determining an increased future biological invasion risk. A few aquatic species modelled at the regional scale reported a net loss in the pooled niches compared to their scientific survey niches, suggesting that citizen science data may also lead to contraction in pooled niches. For these species, models predicted a lower future biological invasion risk. These findings indicate that citizen science data may represent a valuable contribution to predicting future spread of invasive alien species, especially within national‐scale programmes. At the same time, citizen science data collected on species poorly known to citizen scientists, or in strictly local contexts, may strongly affect the niche quantification of these taxa and the prediction of their future biological invasion risk.

Largemouth Bass (Micropterus salmoides, LMB) and Smallmouth Bass (Micropterus dolomieu, SMB) are among the most highly invasive species across the globe, but are simultaneously among the most highly sought-after game fish. To explain these disparate views, data on invasive status and angling participation of these two species were compiled at the country level. Largemouth Bass were found established in 62 countries on five continents, whereas SMB were found established in only nine countries on the same five continents. Invasive risk assessments were disparate between the species, with more for SMB (N = 29) than LMB (N = 27). In every instance save one (Finland), SMB were considered “invasive” compared to LMB, which were “invasive” in only 74% of assessments. Twenty-eight countries with non-native black bass have groups that participate in high-profile fishing tournament such the Black Bass World Championship, BASS (Bass Anglers Sportsmans Society) Nation, and Major League Fishing. Most countries with fishing tournaments occur in countries with established LMB populations than in countries with established SMB populations, suggesting a greater economic importance on LMB fishing. The struggle between conserving biodiversity and relying upon economic benefits from fishing for introduced species is a wicked problem likely to continue into the future.

Advances in technology have equipped paleobiologists with new analytical tools to assess the fossil record. The functional traits of vertebrates have been used to infer paleoenvironmental conditions. In Quaternary deposits, birds are the second-most-studied group after mammals. They are considered a poor paleoambiental proxy because their high vagility and phenotypic plasticity allow them to respond more effectively to climate change. Investigating multiple groups is important, but it is not often attempted. Biogeographical and climatic niche information concerning small mammals, reptiles, and birds have been used to infer the paleoclimatic conditions present during the Late Pleistocene at San Josecito Cave (~28,000 14C years BP), Mexico. Warmer and dryer conditions are inferred with respect to the present. The use of all of the groups of small vertebrates is recommended because they represent an assemblage of species that have gone through a series of environmental filters in the past. Individually, different vertebrate groups provide different paleoclimatic information. Birds are a good proxy for inferring paleoprecipitation but not paleotemperature. Together, reptiles and small mammals are a good proxy for inferring paleoprecipitation and paleotemperature, but reptiles alone are a bad proxy, and mammals alone are a good proxy for inferring paleotemperature and precipitation. The current paleoclimatic results coupled with those of a previous vegetation structure analysis indicate the presence of non-analog paleoenvironmental conditions during the Late Pleistocene in the San Josecito Cave area. This situation would explain the presence of a disharmonious fauna and the extinction of several taxa when these conditions later disappeared and do not reappear again.

Freshwater ecosystems are highly vulnerable to the detrimental impacts of both biological invasions and climate change. Piscivorous alien fishes drive populations of small-bodied native fishes to extinction and warming is already driving extreme temperature events in lakes and rivers globally. Here, we use Ecological Niche Modelling (ENM) to predict how climate change will alter the geographical space of six alien fishes and five native fish genera (which include multiple endemic species) in Turkey, a hotspot of freshwater fish diversity. The models predicted that the geographical space of the alien fishes already present in Turkey would generally increase (including pikeperch Sander lucioperca and perch Perca fluviatilis ), but with the most substantial increases in largemouth bass Micropterus salmoides , a species not yet present in Turkey but that is invasive in countries nearby and is highly popular for sport angling. For the native fish genera, general predictions were for reduced geographical space, especially in the south and east of the country, suggesting the endemic species will become increasingly imperilled in future. Their populations will also be at increasing risk of deleterious impacts from the alien piscivores, as the predictions were also for increasing overlaps in the geographical space of both the alien fishes and native fish genera. These predictions suggest that the conservation of these endemic species need to consider measures on preventing both the introduction of alien species (e.g. largemouth bass) and the further dispersal of extant alien species (e.g. pikeperch), as well as habitat interventions that will limit the effects of climate change on their populations. These results also indicate that the combination of climate change and alien invasions could have substantial impacts on—and similar—hotspots of freshwater diversity.

Aim We estimate and compare niche position, marginality and breadth of Iberian inland fishes at three geographical extents (regional, restricted to the species’ range and global) to understand the effect of spatial scale on niche metrics. Furthermore, we investigate differences in niche metrics between native and alien fish, and test for associations with introduction date of alien species and niche characterization to better understand their invasion process. Location Iberian Peninsula and global. Time period 2000–2020. Major taxa studied Fifty-one native and 17 alien inland fish species from the Iberian Peninsula. Methods Outlying mean index (OMI) analyses were used to estimate the niche position, marginality and breadth of Iberian inland fishes. Climatic OMI analyses were computed at three different scales (regional, restricted to the species’ range and global). Permutational analyses of variance (PERMANOVAs) were used to test for differences in niche position, marginality and breath among native and alien species. Results Niche metrics differed depending on the geographical extent of the investigation, as well as with respect to species origin (native versus alien). Differences in climatic niche position between native and alien species observed at the global scale were non-existent at the regional scale. The niche breadth of widely distributed alien species was highly underestimated when only considering the invaded region, and further influenced by the first date of of species introduction. Main conclusions Estimating niches of freshwater species, especially of alien invaders, should carefully consider the geographical extent of the investigation. We suggest that analyses that jointly consider regional and global scales will improve the estimation of niche metrics of widely distributed organisms, particularly regarding species climatic niche, and the assessment of the invasive potential of species.

Integrating thermal physiology with environmental temperature is essential to understanding distributions of species and vulnerability to climate change. Warming tolerance – the difference between an organism's maximum thermal tolerance (Tmax) and maximum habitat temperature (Thab) – is frequently used to integrate organismal sensitivity and environmental exposure. Traditionally, applications of warming tolerance define Tmax and Thab as invariable magnitudes, yet tolerance magnitude depends on exposure duration, and diel temperature cycles expose organisms to a range of temperature magnitudes and durations. How traditional (i.e. acute) estimates of warming tolerance compare to estimates from prolonged exposures remains poorly understood. In this study, magnitude–duration curves for tolerances of one cold‐water, two cool‐water and one warm‐water species of freshwater fish were compiled from the literature and compared to magnitude–duration exposures from 66 streams across the eastern United States. Warming tolerances were estimated for exposure durations spanning 0.01–24 h. Current acute (0.01 h) warming tolerances ranged from median 6.30°C for the cold‐water species to 9.68°C for the warm‐water species. The lowest warming tolerances corresponded to prolonged exposures lasting median 3.85–5.30 h among species and were 2.51–4.38°C lower than acute estimates. Although acute estimates remained positive in historically occupied and unoccupied streams (6.30 versus 2.33°C), estimates based on prolonged exposure were positive at occupied streams of the cold‐water species but transitioned to negative in unoccupied streams (2.19 versus −1.12°C). Acute warming tolerances for the cold‐water species also remained positive under future climate (6.29–4.23°C) but approached zero at prolonged durations (2.19–0.09°C) and transitioned to negative for 47.2% of streams. Results demonstrate that acute measures of Tmax and Thab overestimate warming tolerances and therefore underestimate climate change vulnerability. Integrating magnitude–duration relationships into warming tolerance estimates can elucidate physiological mechanisms underlying species distributions and can improve accuracy of climate change vulnerability assessments.

An important driver behind introductions for aquaculture of alien fish species into Pacific Island Countries and Territories (PICTs) is a lack of knowledge about domestication suitability and specific culture requirements of indigenous taxa. Introductions may be appropriate in some circumstances, but in other circumstances, the associated risks may outweigh the benefits, so greater understanding of indigenous species' aquaculture potential is important. This review summarises literature for indigenous freshwater food fish species from Papua New Guinea, Fiji, Vanuatu, the Solomon Islands, Samoa and Tonga, and evaluates their aquaculture potential for food security and/or small‐scale livelihoods. A species selection criteria incorporating economic, social, biological and environmental spheres was used to score 62 candidate species. Tilapia (Oreochromis mossambicus and O. niloticus) now established in PICTs were evaluated for comparison. Results show that 13 species belonging to the families Mugilidae (Mullets), Terapontidae (Grunters), Kuhliidae (Flagtails) and Scatophagidae (Scats) have the highest culture potential according to selection criteria. These feed at a relatively low trophic level (are herbivores/detritivores), have comparatively fast growth rates and overall possess characteristics most amenable for small‐scale, inland aquaculture. The four top‐ranked candidates are all mountain mullets Cestraeus spp., followed by Nile tilapia (Oreochromis niloticus). Lower ranked candidates include three other mullets (Planiliza melinoptera, P. subviridis and Mugil cephalus) and rock flagtail Kuhlia rupestris. Importantly, many species remain data deficient in aspects of their reproductive biology or culture performance. Species profiles and ranked priority species by country are provided with logistical, technological and environmental assessments of country capacities to culture each species.

A direct consequence of sea warming is the shift in the distribution range of thermo-tolerant species that have the potential to determine novel inter-specific interactions, ultimately altering food web structures and ecosystem processes. In this study, we investigated the trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766), a pelagic predator that has recently expanded its distribution in the Mediterranean basin and for which scant information is available on its functional role in recently-colonised areas. Nitrogen and carbon stable isotopes were determined in muscle tissues of bluefish specimens collected in south-east Italy in the Gulf of Taranto (NW Ionian Sea) and in the Strait of Otranto (SW Adriatic Sea) at two coastal sites showing contrasting oceanographic conditions. The bluefish trophic position (TP) was estimated using locally abundant forage fish species as isotopic baselines. The results indicated for bluefish from the Strait of Otranto a TP value of 5.1, significantly higher than that determined in the Gulf of Taranto (4.2), and exceeding stomach content-based estimations reported by the online database FishBase and by literature sources. A synthesis of 30 publications reporting isotopic data for the bluefish and its potential prey at a global scale indicated that the species’ trophic position varied considerably between 2.7 and 5.2. The observed variability depended on location and on the baseline species used in the estimations. Yet, a significant difference in trophic position was observed for bluefish from transitional and inshore environments as compared with offshore areas, mirroring the results obtained from the Gulf of Taranto and the Strait of Otranto. The findings of the study highlight the high trophic plasticity characterizing the bluefish in recently colonized areas, suggesting that it may play a key role in facilitating the expansion of its distribution range. However, additional investigations are essential to provide an advanced resolution of the bluefish functional role in Mediterranean coastal food webs.

The continuous decline in biodiversity despite global efforts to create new protected areas calls into question the effectiveness of these areas in conserving biodiversity. Numerous habitats are absent from the global protected area network, and certain taxonomic groups are not being included in conservation planning. Here, we analyzed the level of protection that the current protected area system provides to viper species in the Neotropical region through a conservation gap analysis. We used distribution size and degree of threat to set species-specific conservation goals for 123 viper species in the form of minimum percentage of their distribution that should be covered by protected areas, and assessed the level of protection provided for each species by overlapping their distribution with protected areas of strict protection. Furthermore, using species richness and evolutionary distinctiveness as priority indicators, we conducted a spatial association analysis to detect areas of special concern. We found that most viper species have <1/4 of their distribution covered by protected areas, including 22 threatened species. Also, the large majority of cells containing high levels of species richness were significantly absent from protected areas, while evolutionary distinctiveness was particularly unprotected in regions with relatively low species richness, like northern Mexico and the Argentinian dry Chaco. Our results provide further evidence that vipers are largely being excluded from conservation planning, leaving them exposed to serious threats that can lead to population decline and ultimately extinction.

Beyond providing critical information to biologists, species distributions are useful for naturalists, curious citizens, and applied disciplines including conservation planning and medical intervention. Venomous snakes are one group that highlight the importance of having accurate information given their cosmopolitan distribution and medical significance. Envenomation by snakebite is considered a neglected tropical disease by the World Health Organization and venomous snake distributions are used to assess vulnerability to snakebite based on species occurrence and antivenom/healthcare accessibility. However, recent studies highlighted the need for updated fine-scale distributions of venomous snakes. Pitvipers (Viperidae: Crotalinae) are responsible for >98% of snakebites in the New World. Therefore, to begin to address the need for updated fine-scale distributions, we created VenomMaps, a database and web application containing updated distribution maps and species distribution models for all species of New World pitvipers. With these distributions, biologists can better understand the biogeography and conservation status of this group, researchers can better assess vulnerability to snakebite, and medical professionals can easily discern species found in their area. Measurement(s) Species Distributions Technology Type(s) Geographic Information System • Species Distribution Model (MaxEnt/kuenm) Factor Type(s) Occurrence Records • Environmental Data Sample Characteristic - Organism Crotalinae Sample Characteristic - Location North America • South America