130 research outputs found
Assessing species habitat using Google Street View: A case study of cliff-nesting vultures
The assessment of a species' habitat is a crucial issue in ecology and conservation. While the collection of habitat data has been boosted by the availability of remote sensing technologies, certain habitat types have yet to be collected through costly, on-ground surveys, limiting study over large areas. Cliffs are ecosystems that provide habitat for a rich biodiversity, especially raptors. Because of their principally vertical structure, however, cliffs are not easy to study by remote sensing technologies, posing a challenge for many researches and managers working with cliff-related biodiversity. We explore the feasibility of Google Street View, a freely available on-line tool, to remotely identify and assess the nesting habitat of two cliff-nesting vultures (the griffon vulture and the globally endangered Egyptian vulture) in northwestern Spain. Two main usefulness of Google Street View to ecologists and conservation biologists were evaluated: i) remotely identifying a species' potential habitat and ii) extracting fine-scale habitat information. Google Street View imagery covered 49% (1,907 km) of the roads of our study area (7,000 km2). The potential visibility covered by on-ground surveys was significantly greater (mean: 97.4%) than that of Google Street View (48.1%). However, incorporating Google Street View to the vulture's habitat survey would save, on average, 36% in time and 49.5% in funds with respect to the on-ground survey only. The ability of Google Street View to identify cliffs (overall accuracy = 100%) outperformed the classification maps derived from digital elevation models (DEMs) (62-95%). Nonetheless, high-performance DEM maps may be useful to compensate Google Street View coverage limitations. Through Google Street View we could examine 66% of the vultures' nesting-cliffs existing in the study area (n = 148): 64% from griffon vultures and 65% from Egyptian vultures. It also allowed us the extraction of fine-scale features of cliffs. This World Wide Web-based methodology may be a useful, complementary tool to remotely map and assess the potential habitat of cliff-dependent biodiversity over large geographic areas, saving survey-related costs.PMT was supported by a postdoctoral grant funded by Junta de Comunidades de Castilla-La Mancha and Fondo Social Europeo.Peer Reviewe
Nested species- rich networks of scavenging vertebrates support high levels of interspecific competition
et al.Disentangling the processes that shape the organization of ecological assemblages and its implications for species coexistence is one of the foremost challenges of ecology. Although insightful advances have recently related community composition and structure with species coexistence in mutualistic and antagonistic networks, little is known regarding other species assemblages, such as those of scavengers exploiting carrion. Here we studied seven assemblages of scavengers feeding on ungulate carcasses in mainland Spain. We used dynamical models to investigate if community composition, species richness and structure (nestedness) affect species coexistence at carcasses. Scavenging networks showed a nested pattern in sites where highly efficient, obligate scavengers (i.e., vultures) were present and a non- nested pattern everywhere else. Griffon Vulture ( Gyps fulvus ) and certain meso- facultative mammalian scavengers (i.e., red fox, Vulpes vulpes, and stone marten, Martes foina ) were the main species contributing to nestedness. Assemblages with vultures were also the richest ones in species. Nested species- rich assemblages with vulture presence were associated with high carcass consumption rates, indicating higher interspecific competition at the local scale. However, the proportion of species stopping the consumption of carrion (as derived from the competitive dynamic model) stabilized at high richness and nestedness levels. This suggests that high species richness and nestedness may characterize scavenging networks that are robust to high levels of interspecific competition for carrion. Some facilitative interactions driven by vultures and major facultative scavengers could be behind these observations. Our findings are relevant for understanding species' coexistence in highly competitive systems.E. Sebastián-González and P. R. Guimarães benefited from FAPESP Research Foundation grants numbers 2011/17968-2 and 2009/054422-8, respectively; E. Sebastián-González is currently funded under the NSF grant NSF Award #1345247, M. Moleón by a postdoctoral grant from the Spanish Ministry of Education (Plan Nacional de I+D+I 2008-2011), J. P. Gibert by an Other Fellowship and SBS Special Funds (U. of N.), and P. Mateo-Tomás by a postdoctoral grant of the Junta de Comunidades de Castilla- La Mancha and Fondo Social Europeo. The study was supported by the Spanish Ministry of Science and Innovation through projects 23/2007 ICTS- RBD, CGL2009-12753-C02-02, and CGL2012-40013-C02-02, FEDER funds, the Generalitat Valenciana through project ACOMP/2012/147, and the Junta de Andalucía through project RNM-1925.Peer Reviewe
Nested species- rich networks of scavenging vertebrates support high levels of interspecific competition.
Disentangling the processes that shape the organization of ecological assemblages and its implications for species coexistence is one of the foremost challenges of ecology. Although insightful advances have recently related community composition and structure with species coexistence in mutualistic and antagonistic networks, little is known regarding other species assemblages, such as those of scavengers exploiting carrion. Here we studied seven assemblages of scavengers feeding on ungulate carcasses in mainland Spain. We used dynamical models to investigate if community composition, species richness and structure (nestedness) affect species coexistence at carcasses. Scavenging networks showed a nested pattern in sites where highly efficient, obligate scavengers (i.e., vultures) were present and a non- nested pattern everywhere else. Griffon Vulture ( Gyps fulvus ) and certain meso- facultative mammalian scavengers (i.e., red fox, Vulpes vulpes, and stone marten, Martes foina ) were the main species contributing to nestedness. Assemblages with vultures were also the richest ones in species. Nested species- rich assemblages with vulture presence were associated with high carcass consumption rates, indicating higher interspecific competition at the local scale. However, the proportion of species stopping the consumption of carrion (as derived from the competitive dynamic model) stabilized at high richness and nestedness levels. This suggests that high species richness and nestedness may characterize scavenging networks that are robust to high levels of interspecific competition for carrion. Some facilitative interactions driven by vultures and major facultative scavengers could be behind these observations. Our findings are relevant for understanding species' coexistence in highly competitive systems
Functional traits driving species role in the structure of terrestrial vertebrate scavenger networks
Species assemblages often have a non-random nested organization, which in vertebrate scavenger (carrion-consuming) assemblages is thought to be driven by facilitation in competitive environments. However, not all scavenger species play the same role in maintaining assemblage structure, as some species are obligate scavengers (i.e., vultures) and others are facultative, scavenging opportunistically. We used a database with 177 vertebrate scavenger species from 53 assemblages in 22 countries across five continents to identify which functional traits of scavenger species are key to maintaining the scavenging network structure. We used network analyses to relate ten traits hypothesized to affect assemblage structure with the “role” of each species in the scavenging assemblage in which it appeared. We characterized the role of a species in terms of both the proportion of monitored carcasses on which that species scavenged, or scavenging breadth (i.e., the species “normalized degree”), and the role of that species in the nested structure of the assemblage (i.e., the species “paired nested degree”), therefore identifying possible facilitative interactions among species. We found that species with high olfactory acuity, social foragers, and obligate scavengers had the widest scavenging breadth. We also found that social foragers had a large paired nested degree in scavenger assemblages, probably because their presence is easier to detect by other species to signal carcass occurrence. Our study highlights differences in the functional roles of scavenger species and can be used to identify key species for targeted conservation to maintain the ecological function of scavenger assemblages.Generalitat Valenciana SEJI/2018/024, APOSTD/2019/016, CIDEGENT/ 2020/030, ACIF/2019/056Ministerio de Educación y Cultura CI-2017-32149, FJCI-2015-25632, IJC2018-036642-I, YC-2019-027216-I, RYC-2015-19231, RYC-2017-2273, GL2012-40013-C02-01/02, CGL2015- 66966-C2-1-R, CGL2015-66966-C2-1-R2, CGL2017-89905-R, RTI2018-099609-B-C21, RTI2018-099609-B-C22Govern de les Illes Balears PD/039/201National Science Centre in Poland 2013/08/M/ NZ9/00469, 2016/22/Z/NZ8/00Slovenian Research Agency P4-0059US Department of Energy DE- EM000439USA National Science Foundation #1255913California Department of Fish & Wildlife P0880013Junta de Andalucía RNM-192
Habitat selection and diet of Western Capercaillie
P. 260-272Ecological features and conservation requirements of populations at the latitudinal limits
of a species’ geographical range frequently differ from those in other parts of the range.
Identifying such differences is key to implementing effective conservation strategies for
threatened range-edge populations especially, in the context of rapid global warming, at
the lower-latitude range edge. We studied habitat selection and diet of the endangered
Cantabrian Capercaillie Tetrao urogallus cantabricus in a recently discovered population
at the southernmost edge of the sub-species’ range. This is the only Western Capercaillie
population in the Mediterranean biogeographical region. We combined non-systematic
surveys based on questionnaires, reports and field sampling with data from radiotracking
to assess habitat selection. Diet was surveyed by micro-histological methods from droppings
collected in the new population, which inhabits Pyrenean Oak Quercus pyrenaica
forests and Scots Pine Pinus sylvestris plantations, and in two Cantabrian populations
inhabiting Eurosiberian forests. Capercaillie preferred large (> 500 ha) and medium-sized
(100–500 ha) Pyrenean Oak forest fragments and large Scots Pine plantations. Forest
fragments smaller than 100 ha and non-forested habitats were always avoided. Diet differed
markedly between Mediterranean and Eurosiberian populations. Bilberry Vaccinium
myrtillus is common in the diet of most Capercaillie populations but was scarce in the
study area and so was rare in the diet of the new population. Instead, Rockrose Halimium
lasianthum was described for the first time as a major food resource for the Capercaillie
and was consumed in autumn and winter. Pine needles were also heavily consumed in
winter. We document for the first time the strong preference of Capercaillie for Pyrenean
Oak forests and a moderately high consumption of the leaves, buds and acorns of this
tree species throughout the year. Habitat selection and diet of this Mediterranean
population differ from those of the core Cantabrian and other populations. Our results
suggest a wider environmental tolerance (phenotypic plasticity) in the species than previously
recognized. We advocate specific protection for this unique range-edge Capercaillie
population and its Pyrenean Oak forest habitatS
Bottom-up Fabrication and Atomic-Scale Characterization of Triply Linked, Laterally π-Extended Porphyrin Nanotapes**
Magnetic Interplay between π-Electrons of Open-Shell Porphyrins and d-Electrons of Their Central Transition Metal Ions
Aporte al conocimiento de la estructura interna de la tierra a partir de observaciones GNSS
Se ha podido probar que los receptores satelitales, pueden observar la llegada de ondas superficiales y permiten conocer rápidamente el desplazamiento o deformación co-sísmica. En este trabajo se plantea la obtención de curvas de dispersión, que permiten conocer las velocidades a las que se transmiten las ondas superficiales a partir de observaciones GNSS
Estimating and Modelling Bias of the Hierarchical Partitioning Public-Domain Software: Implications in Environmental Management and Conservation
BACKGROUND: Hierarchical partitioning (HP) is an analytical method of multiple regression that identifies the most likely causal factors while alleviating multicollinearity problems. Its use is increasing in ecology and conservation by its usefulness for complementing multiple regression analysis. A public-domain software "hier.part package" has been developed for running HP in R software. Its authors highlight a "minor rounding error" for hierarchies constructed from >9 variables, however potential bias by using this module has not yet been examined. Knowing this bias is pivotal because, for example, the ranking obtained in HP is being used as a criterion for establishing priorities of conservation. METHODOLOGY/PRINCIPAL FINDINGS: Using numerical simulations and two real examples, we assessed the robustness of this HP module in relation to the order the variables have in the analysis. Results indicated a considerable effect of the variable order on the amount of independent variance explained by predictors for models with >9 explanatory variables. For these models the nominal ranking of importance of the predictors changed with variable order, i.e. predictors declared important by its contribution in explaining the response variable frequently changed to be either most or less important with other variable orders. The probability of changing position of a variable was best explained by the difference in independent explanatory power between that variable and the previous one in the nominal ranking of importance. The lesser is this difference, the more likely is the change of position. CONCLUSIONS/SIGNIFICANCE: HP should be applied with caution when more than 9 explanatory variables are used to know ranking of covariate importance. The explained variance is not a useful parameter to use in models with more than 9 independent variables. The inconsistency in the results obtained by HP should be considered in future studies as well as in those already published. Some recommendations to improve the analysis with this HP module are given
Unraveling the real magnitude of illegal wildlife poisoning to halt cryptic biodiversity loss
Illegal wildlife poisoning is a global threat for biodiversity, yet the magnitude of its impact on ecosystems is largely underestimated as most of poisoning episodes remain undetected. Here, we conducted a large-scale field experiment to better understand the real dimension of the illegal wildlife poisoning in terms of composition and number of species and abundance of impacted individuals, as well as the ecological factors driving it. We used camera traps to monitor simulated poison baits placed in 25 study areas in SW Europe and applied Good–Turing theory to estimate the richness of species of the entire assemblage (observed plus undetected). We recorded 3095 individuals from 39 vertebrate species that consumed 94 % of the baits (N = 590). Yet, using sample completeness to estimate the entire species assemblage yielded a total of 47 species exposed to illegal poisoning. The observed assemblage included different trophic and functional groups (from lizards and snakes to apex species among birds and mammals), as well as a 38 % of threatened and near threatened species (according to Spanish and Portuguese vertebrate red list and UICN list). The size (weight) of the bait outstands as a reliable predictor of the number of species (0–8 species/bait, mean = 2) and individuals (0–99 individuals/bait, mean = 5) susceptible to poisoning. The habitat where the bait was placed modulated the abundance of individuals affected (greater in open than in closed habitats). Type of bait and habitat drove the compositional variation of species. Our approach enables uncover entire species assemblages prone to illegal poisoning and their ecological drivers associated, advancing the understanding of the impact of wildlife poisoning in ecosystemsThis work was supported by the project TOXICO funding by “BBVA
FOUNDATION GRANTS TO SCIENTIFIC RESEARCH TEAMS, CALL
2018”. WWF Spain and SEO/BirdLife provided access to the ANTíDOTO
database of wildlife poisoning in Spain. The Ohio Wesleyan University
supported with logistical material (5 camera-traps). JVLB was supported
by the Spanish Ministry of Economy, Industry and Competitiveness
(RYC-2015-18932; CGL2017-87528-R AEI/FEDER EU). JVLB and PMT
were supported by a GRUPIN research grant from the Regional Government of Asturias (AYUD/2021/51314). In Portugal, this study was
financed through the Sentinelas project funded by Fundo Ambiental –
Minist´erio do Ambiente e da Aç˜
ao Clim´
atica. We are grateful to Instituto
da Conservaçao ˜ da Natureza e das Florestas (ICNF), Principado de
Asturias, Junta de Castilla y Leon, ´ Xunta de Galicia, Gobierno de Cantabria, Comunidad de Madrid, Junta de Andalucía, Picos de Europa
National Park, Sierra de Guadarrama National Park, Cabaneros ˜ National
Park and Monfragüe National Park for granted permission
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