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Bellard C, Genovesi P, Jeschke J (2016)
Proceedings of the Royal Society B: Biological Sciences 283(1823) 20152454.
Biological invasions as drivers of biodiversity loss have recently been challenged. Fundamentally, we must know where species that are threatened by invasive alien species (IAS) live, and the degree to which they are threatened. We report the first study linking 1372 vertebrates threatened by more than 200 IAS from the completely revised Global Invasive Species Database. New maps of the vulnerability of threatened vertebrates to IAS permit assessments of whether IAS have a major influence on biodiversity, and if so, which taxonomic groups are threatened and where they are threatened. We found that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand. The areas in which IAS-threatened species are located do not fully match the current hotspots of invasions, or the current hotspots of threatened species. The relative importance of biological invasions as drivers of biodiversity loss clearly varies across regions and taxa, and changes over time, with mammals from India, Indonesia, Australia and Europe are increasingly being threatened by IAS. The chytrid fungus primarily threatens amphibians, whereas invasive mammals primarily threaten other vertebrates. The differences in IAS threats between regions and taxa can help efficiently target IAS, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity.
Coro G, Magliozzi C, Vanden Berghe E, Bailly N, Ellenbroek A, Pagano P (2016)
Ecological Modelling 323 61-76.
Estimating absence locations of a species is important in conservation biology and conservation planning. For instance, using reliable absence as much as presence information, species distribution models can enhance their performance and produce more accurate predictions of the distribution of a species. Unfortunately, estimating reliable absence locations is difficult and often requires a deep knowledge of the species’ distribution and of its abiotic and biotic environmental preferences and tolerance. In this paper, we propose a methodology to reconstruct reliable absence information from presence-only information, and the conditions that those presence-only data have to meet to make this possible. Large species occurrence data collections (otherwise called occurrence datasets) contain high quality and expert-reviewed species observation records from scientific surveys. These surveys can be used to retrieve species presence locations, but they also record places where the species in their target list were not observed. Although these absences could be simply due to sampling variation, it is possible to intersect many of these reports to estimate true absence locations, i.e. those due to habitat unsuitability or geographical hindrances. In this paper, we present a method to generate reliable absence locations of this type for marine species, using scientific surveys reports contained in the Ocean Biogeographic Information System (OBIS), an authoritative species occurrence dataset. Our method spatially aggregates information from surveys focussing on the same target species. It detects absence locations for a given species as those locations in which repeated surveys (that included the species of interest in their target list) reported information only on other species. We qualitatively demonstrate the reliability of our method using distribution records of the Atlantic cod as a case study. Additionally, we quantitatively estimate its performance using another authoritative large species occurrence dataset, the Global Biodiversity Information Facility (GBIF). We also demonstrate that our approach has higher accuracy and presents complementary behaviour with respect to another method using environmental envelopes. Our process can support species distribution models (as well as other types of models, e.g. climate change models) by providing reliable data to presence/absence approaches. It can manage regional as well as global scale scenarios and runs within a collaborative e-Infrastructure (D4Science) that publishes it as-a-Service, allowing biologists to reproduce, repeat and share experimental results.
Keywords: Absence locations, Ecological niche modelling, Marine biodiversity, Occurrence data, Scientific surveys, Species distribution maps
Katsanevakis S, Tempera F, Teixeira H (2016)
Diversity and Distributions.
Aim To develop a standardized, quantitative method for mapping cumulative impacts of invasive alien species on marine ecosystems. Location The methodology is applied in the Mediterranean Sea but is widely applicable. Methods A conservative additive model was developed to account for the Cumulative IMPacts of invasive ALien species (CIMPAL) on marine ecosystems. According to this model, cumulative impact scores are estimated on the basis of the distributions of invasive species and ecosystems, and both the reported magnitude of ecological impacts and the strength of such evidence. In the Mediterranean Sea case study, the magnitude of impact was estimated for every combination of 60 invasive species and 13 habitats, for every 10 × 10 km cell of the basin. Invasive species were ranked based on their contribution to the cumulative impact score across the Mediterranean. Results The CIMPAL index showed strong spatial heterogeneity. Spatial patterns varied depending on the pathway of initial introduction of the invasive species in the Mediterranean Sea. Species introduced by shipping gave the highest impact scores and impacted a much larger area than those introduced by aquaculture and the Suez Canal. Overall, invasive macroalgae had the highest impact among all taxonomic groups. These results represent the current best estimate of the spatial variation in impacts of invasive alien species on ecosystems, in the Mediterranean Sea. Main Conclusions A framework for mapping cumulative impacts of invasive alien species was developed. The application of this framework in the Mediterranean Sea provided a baseline that can be built upon with future improved information. Such analysis allows the identification of hotspots of highly impacted areas, and prioritization of sites, pathways and species for management actions.
Keywords: CIMPAL, biological invasions, cumulative impacts, indicators, invasive alien species, pathways
Londei T (2016)
Piapiacs ( Ptilostomus afer Linnaeus, 1766) and yellow-billed oxpeckers ( Buphagus africanus Linnaeus, 1766) avoid proximity when on African buffaloes ( Syncerus caffer Sparrman, 1779)
African Journal of Ecology.
Many African bird species (totalling 96 according to Dean & MacDonald, 1981) show feeding associations with mammals. However, little attention, if any, has been paid to interspecific interactions among birds attending the same mammal. Moreover, except for the red-billed oxpecker (Buphagus erythrorhyncus Stanley, 1814) and yellow-billed oxpecker (Buphagus africanus Linnaeus, 1766), which are obligate ectoparasite gleaners, there are only suggestions for any of the other species about the extent of their dependence on mammals (Dean & MacDonald, 1981). The piapiac (Ptilostomus afer Linnaeus, 1766) is a savannah corvid of sub-Saharan Africa north of the equator, ranging west-eastwards from Senegal to extreme W Kenya (Madge, 2009). Considering its wide distribution, consistent numbers and conspicuous behaviour, it is an understudied species. It is frequently seen on the backs of slowly moving herbivorous mammals, which serve as lookouts not only to catch the insects which the mammal flushes from the ground, but also as feeding substrate for the mammal's ectoparasites. Analysis of stomach contents has been very scarce for the piapiac. Among the 181 specimens listed in the Global Biodiversity Information Facility (http://www.gbif.org/; accessed 25 March 2016), only five specimens (four of which collected in 2 days in the same area) had stomach contents reported, which were all insects, mainly grasshoppers. However, Wilson (1981) found ‘ticks’ in the one piapiac stomach he examined. The piapiac may be second to only the oxpeckers in its apparent (although still understudied) morphological specializations to use grazing mammals for foraging. Interestingly, the piapiac prefers balancing on, rather than clinging to, the mammal's body (Fig. 1). This may be the reason why elephants (Loxodonta africana Blumenbach, 1797) more easily tolerate piapiacs on their sensitive skin (see, e.g. Mundy & Haynes, 1996) and why oxpeckers and not piapiacs are usually found on the sloping back of giraffes (Giraffa camelopardalis Linnaeus, 1758). The search for a stable perch may also explain why piapiacs would especially be attracted to domestic ungulates, quieter animals than their wild counterparts. The suggestion of a partial niche overlap and consequent competition between piapiacs and oxpeckers prompted this study. I chose the African buffalo (Syncerus caffer Sparrman, 1779) as the associated mammal because of its apparent attractiveness for both the piapiacs and the oxpeckers, its abundance in the study area and it being the closest wild African relative of the domestic cattle to which the oxpeckers often become detrimental through wound-feeding (e. g., Weeks, 2000).
Keywords: CIMPAL, biological invasions, cumulative impacts, indicators, invasive alien species, pathways
Pârâu L, Strubbe D, Mori E, Menchetti M, Ancillotto L, Kleunen A et al. (2016)
The Open Ornithology Journal 9(1) 1-13.
Purpose: Alien species are considered one of the major causes contributing to the current loss of biodiversity. Over the past few decades, a large and increasing number of alien species have become invasive in many parts of the world. Their impacts range from competition for resources with native species to damage of urban infrastructure. In Europe, over a thousand alien species are now established, of which 74 are birds. Among 12 established alien parrot species in Europe, Introduction: The Rose-ringed Parakeet (RRP) Psittacula krameri (Scopoli, 1769) is the most abundant and widespread. Since the 1960's, RRPs have established more than 100 wild populations in several European countries. For Western Europe, long-term demographic data indicate the species has grown considerably in number, although some populations have failed to persist. Data: Is scarce and dispersed for countries in Central, Eastern and Northern Europe. Therefore, here we present detailed demographic data of RRP for 90 populations in 10 European countries. Furthermore, we present information on the status of the species in another 27 European countries, for which previously no data were published. Conclusion: Our synthesis reveals a positive demographic trend across the continent, although locally, some populations appear to have reached carrying capacity.
Keywords: Demography, Europe, Invasive alien species, Parrots, Population, Psittaciformes
Ancillotto L, Strubbe D, Menchetti M, Mori E (2015)
An overlooked invader? Ecological niche, invasion success and range dynamics of the Alexandrine parakeet in the invaded range
Parrots and parakeets (Aves, Psittaciformes) are prominent among avian invaders, as more than 16 % of living species are currently breeding with at least one population outside their native range. Most studies have been carried out on ring-necked and monk parakeets, as they are the most successful invasive parrots globally. Recently, however, reports of invasive Alexandrine parakeet Psittacula eupatria have increased. Here, we summarize the current knowledge on the current occurrence of Alexandrine parakeets outside the natural range and assess the degree of niche conservatism during the invasion process. Our results show that Alexandrine parakeets have established invasive populations predominantly in Europe, parts of the Middle east and Far Eastern countries such as Japan and Singapore. During the ongoing invasion of Europe, the Alexandrine parakeet considerably expanded its niche into colder climates with respect to those occupied in the native range. Our results offer some support to the hypothesis that interspecific facilitation with previously established ring-necked parakeets Psittacula krameri may contribute to niche expansion and invasion success of congeneric Alexandrine parakeets. Species Distribution Models including both native and invaded range occurrence data predict a high invasion risk across multiple parts of the globe where the species is currently not yet present, thus indicating a high potential for the species for further invasion success and range expansion.
Keywords: Interspecific facilitation, Niche conservatism, Psittaciformes, Psittacula eupatria, Range expansion
Barredo J, Strona G, de Rigo D, Caudullo G, Stancanelli G, San-Miguel-Ayanz J (2015)
Assessing the potential distribution of insect pests: case studies on large pine weevil ( Hylobius abietis L) and horse-chestnut leaf miner ( Cameraria ohridella ) under present and future climate conditions in European forests
EPPO Bulletin 45(2) 273-281.
Forest insect pests represent a serious threat to European forests and their negative effects could be exacerbated by climate change. This paper illustrates how species distribution modelling integrated with host tree species distribution data can be used to assess forest vulnerability to this threat. Two case studies are used: large pine weevil (Hylobius abietis L) and horse-chestnut leaf miner (Cameraria ohridella Deschka & Dimič) both at pan-European level. The proposed approach integrates information from different sources. Occurrence data of insect pests were collected from the Global Biodiversity Information Facility (GBIF), climatic variables for present climate and future scenarios were sourced, respectively, from WorldClim and from the Research Program on Climate Change, Agriculture and Food Security (CCAFS), and distributional data of host tree species were obtained from the European Forest Data Centre (EFDAC), within the Forest Information System for Europe (FISE). The potential habitat of the target pests was calculated using the machine learning algorithm of Maxent model. On the one hand, the results highlight the potential of species distribution modelling as a valuable tool for decision makers. On the other hand, they stress how this approach can be limited by poor pest data availability, emphasizing the need to establish a harmonised open European database of geo-referenced insect pest distribution data. Évaluation de la répartition potentielle des insectes nuisibles: études de cas sur le grand charançon du pin (Hylobius abietis L.) et sur la mineuse du marronnier (Cameraria ohridella) dans les conditions climatiques actuelles et futures dans les forêts européennes Les insectes nuisibles des forêts représentent une menace sérieuse pour les forêts européennes et leurs effets négatifs pourraient être aggravés par le changement climatique. Cet article illustre l'utilisation de la modélisation de la répartition des espèces, intégrée aux données de répartition des arbres-hôtes, pour évaluer la vulnérabilité des forêts à cette menace. Deux études de cas sont utilisées, toutes deux au niveau paneuropéen, pour le grand charançon du pin (Hylobius abietis L.) et la mineuse du marronnier (Cameraria ohridella Deschka & Dimič). L'approche proposée utilise des informations de différentes sources. Les données sur la présence des insectes nuisibles proviennent du service mondial d'information sur la biodiversité (‘Global Biodiversity Information Facility’, GBIF), les variables climatiques pour le climat actuel et des scénarios futurs ont été obtenues, respectivement, à partir de WorldClim et du Programme de recherche sur le changement climatique, l'agriculture et la sécurité alimentaire (CCAFS), et les données sur la répartition des arbres-hôtes ont été obtenues auprès du Centre européen de données sur les forêts (EFDAC), qui fait partie du système d'information forestière pour l'Europe (‘Forest Information System for Europe’, FISE). L'habitat potentiel des ravageurs étudiés a été calculé en utilisant l'algorithme d'apprentissage automatique du modèle Maxent. D'une part, les résultats indiquent que la modélisation de la répartition des espèces peut devenir un outil précieux pour les décideurs. D'autre part, ils indiquent que cette approche peut être limitée par le manque de données sur les organismes nuisibles, renforçant ainsi la nécessité de créer une base de données européenne harmonisée et ouverte pour les données géo-référencées sur la répartition des insectes nuisibles.
Keywords: Interspecific facilitation, Niche conservatism, Psittaciformes, Psittacula eupatria, Range expansion
Bradley B, Early R, Sorte C (2015)
Global Ecology and Biogeography n/a-n/a.
Aim Our understanding of potential ranges for native and non-native species is often based on their current geographic distributions. Non-native species have had less time than co-occurring native species to expand their ranges following introduction, so non-native ranges may under-represent suitable conditions. Therefore it is often assumed that species distribution models will predict disproportionately smaller potential ranges for non-natives than natives. We compare the distributions of native, endemic, alien and invasive plants to determine how the different range attributes of these groups might influence ecological forecasting. Location Continental USA. Methods We compared the geographic ranges of 13,575 plant species (9402 native, 2397 endemic, 1201 alien and 755 invasive) using (1) US only and (2) global distribution data from herbarium records. We calculated US longitudinal and latitudinal range extents as potential indicators of range-limiting factors, modelled potential range based on climate using principal components analysis, and calculated occupancy of potential ranges (range infilling). Results Contrary to expectations, modelled potential ranges were significantly larger for non-natives than natives, even for species with few occurrences. Distributions of native species, not invasive species, appeared strongly limited longitudinally. However, invasive plants occupied substantially less area within their climatically suitable ranges than native plants (lower range infilling). Main conclusions Invasive plant distributions were consistently broader, both climatically and geographically, than comparable native species. This suggests that invasive plant distribution models at regional scales are not underpredicting potential ranges relative to models for native species. In contrast, the comparatively limited longitudinal ranges of native species suggest a high degree of non-climatic limitation, which is likely to cause distribution models to underpredict the potential ranges of native species. Invasive plants have not achieved the degree of range infilling expected relative to natives. Thus, plants introduced to the US still have plenty of space to invade.
Keywords: Alien, bioclimatic envelope model, dispersal, ecological niche model, equilibrium, exotic, introduced, occupancy, plant invasion
Carta A, Peruzzi L (2015)
Testing the large genome constraint hypothesis: plant traits, habitat and climate seasonality in Liliaceae
The factors driving genome size evolution in Liliaceae were examined. In particular, we investigated whether species with larger genomes are confined to less stressful environments with a longer vegetative season. We tested our hypotheses by correlating the genome size with other plant traits and environmental variables. To determine the adaptive nature of the genome size, we also compared the performances of Brownian motion (BM) processes with those inferred by Ornstein–Uhlenbeck (OU) models of trait evolution. A positive correlation of genome size with plant size, mean temperature and habitat moisture and a negative correlation with altitude and precipitation seasonality were found. Models of trait evolution revealed a deviation from a drift process or BM. Instead, changes in genome size were significantly associated with precipitation regimes according to an OU process. Specifically, the evolutionary optima towards which the genome size evolves were higher for humid climates and lower for drier ones. Taken together, our results indicate that the genome size increase in Liliaceae is constrained by climate seasonality.
Keywords: Liliaceae, genome size evolution, models of trait evolution, phylogenetic comparative analysis, plant–climate interactions
Coro G, Magliozzi C, Ellenbroek A, Pagano P (2015)
Ecological Modelling 305 29-39.
The giant squid (Architeuthis) has been reported since even before the 16th century, and has recently been observed live in its habitat for the first time. Among the species belonging to this genus, Architeuthis dux has received special attention from biologists. The distribution of this species is poorly understood, as most of our information stems from stranded animals or stomach remains. Predicting the habitat and distribution of this species, and more in general of difficult to observe species, is important from a biological conservation perspective. In this paper, we present an approach to estimate the potential distribution of A. dux at global scale, with relative high resolution (1-degree). Our approach relies on a complex preparation phase, which improves the reliability of presence, absence and environmental data correlated to the species habitat. We compare our distribution with those produced by state-of-the-art approaches (MaxEnt and AquaMaps), and use an expert-drawn map as reference. We demonstrate that our model projection is in agreement with the expert's map and is also compliant with several biological assessments of the species habitat and with recent observations. Furthermore, we show that our approach can be generalized as a paradigm that is applicable to other rare species.
Keywords: AquaMaps, Ecological niche modelling, Maximum entropy, Neural networks, Rare species