Suchergebnisse

In this study we present a review on the diet of the feral cat on the Canary archipelago, providing the first data from the reliet laurel forest (Garajonay National Park). Among the 403 prey items identified in this habitat, rats were most numerous followed by reptiles. A total of 1.047 scat groups has been studied in the lat eight years from the main habitats of the Canaries. Most of the 2.963 prey items identified represent introduced mammals (rabbit, Oryctolagus cuniculus; mouse, Mus cf.musculus and rat. Rattus sp.). These prey were commonly captured in most habitats with the exception of high mountain scrub. In this habitat, reptiles were taken instead introduced mammals. They were also more commonly included in the diet from open grpund and open forest than from the denser forest. Birds were more frecuently consumed in the forest than in open areas. Anthropods appeared in significant proportions in the scats from habitats where these items reached high numbers. The results indicate that the diet of feral cats clearly varies according to the different habitats. ; The authors would like to express their gratitude to Ornistudio S. L. specially to K. Emmerson, M. Oramas and E. C. Hernández for donating some of the material and data. A. Martín and J. C. Rando identified some prey items, and the ICONA's personal from La Gomera Island gave logistic support. All the studies carried out on the diet of feral cats on the Canaries were done without any government economie support. Bernie Zonfrillo revised the manuscript and made helpful comments. ; Peer reviewed

9 pages, 2 figures, 3 tables. ; We found a total of 987 prey in the 500 scats of feral cats Felis silvestris catus Linnaeus, 1758 analyzed in the present study. Introduced mammals (rabbits, rats and mice) constituted the most important prey both in percentage and biomass. Reptiles were the second most important prey, being more frequent than birds and invertebrates. Mammals were the most frequently eaten group in all five main habitats of the island, being more frequent than the remainder of prey in the laurel forest. Rabbits appeared more often in the temperate forest, rats in the laurel forest and mice in the high mountain. Birds were more frequently captured in the three higher habitats (laurel and pine forest, and high mountain) than in the two lower ones (xerophytic shrub and temperate forest). Reptiles were preyed on less in the laurel forest than in the other main habitats. Morisita index indicates a high trophic overlap among the different habitats with the exception of the laurel forest which shows important differences from the other habitats. Levin's niche-breadth was broader in the xerophytic shrub and narrower in the temperate forest, reaching intermediate levels in the other three main habitats. The results obtained in the present study evidence a general pattern in the trophic ecology among similar habitats in the different subtropical Canarian islands. However, some important differences exist that could beafunction of the differential prey availability and composition in each ecosystem. ; We thank the Unidad de Medio Ambiente del Cabildo Insular de La Palma (Insular Government) for its logistic support.

In this study, we present the first data on diet and impacts of feral cats on a semiarid island (Fuerteventura, Canary Islands). A total of 614 prey was identified in the 209 scats analysed. Introduced mammals, especially rabbits and mice, were the most consumed vertebrate prey and constituted more than 90% of biomass. Barbary ground squirrels, Algerian hedgehogs, and rats were preyed upon less even though they were abundant on the island. Invertebrates, mainly Orthoptera, Coleoptera, Hymenoptera and Odonata, were the second most important prey items (in terms of actual numbers) but they contributed only minimally with respect to biomass (<1.1%). The presence of terrestrial molluscs in the diet was interesting because they are a rare prey in an insular context. Birds and reptiles occurred at a low frequency. A total of 677 seeds was counted, mainly belonging to Lycium intricatum (Solanaceae) and two unidentified plant species. Levin's niche breadth was narrow due to the high consumption of mammals. Morisita's index showed a similar trophic overlap in diet with respect to the other xeric habitats of the Canarian archipelago. Considering that more than 90% of biomass corresponded to introduced mammals, we conclude that feral cats are not having a large direct impact on the native prey species.

A Houbara survey of Lanzarote and the small island of Graciosa, during December 1993, resulted in a total count of 146 birds and an estimated total population of about 400 Houbaras. These numbers are higher than found on most previous surveys of Fuerteventura, considered as the main stronghold of this subspecies, and indicate that the Houbara population on Lanzarote is much more important than was formerly supposed. A study of habitat preferences showed that the species tended to select zones with greater height of shrubs. ; Un censo de hubaras efectuado en las islas de Lanzarote y Graciosa, en diciembre de 1993, permitió contabilizar un total de 146 aves y estimar la población en alrededor de 400 hubaras. Estos resultados son superiores a la mayoría de los datos obtenidos hasta la fecha en la vecina isla de Fuerteventura, considerada como el principal refugio de la especie en el archipiélago canario. Lanzarote es pues una isla que matiene efectivos mucho más importantes que los supuestos hasta la fecha. En cuanto a las preferencias de hábitat, las aves seleccionaron aquellas zonas que presentaban una mayor altura de la vegetación. ; We would like to thank Keith Emmerson for his invaluable information on previous censuses. Pedro Jordano assisted during the dta analysis. Nigel J. Collar and an anonymous referee made useful comments on the manuscript. This study was supported by the Viceconsejería de Medio Ambiente of the Canary Government. ; Peer reviewed

Invasive plant species are increasingly altering species composition and the functioning of ecosystems from a local to a global scale. The grass species Pennisetum setaceum has recently raised concerns as an invader on different archipelagos worldwide. Among these affected archipelagos are the Canary Islands, which are a hotspot of endemism. Consequently, conservation managers and stakeholders are interested in the potential spreading of this species in the archipelago. We identify the current extent of the suitable habitat for P. setaceum on the island of La Palma to assess how it affects island ecosystems, protected areas (PAs), and endemic plant species richness. We recorded in situ occurrences of P. setaceum from 2010 to 2018 and compiled additional ones from databases at a 500 m × 500 m resolution. To assess the current suitable habitat and possible distribution patterns of P. setaceum on the island, we built an ensemble model. We projected habitat suitability for island ecosystems and PAs and identified risks for total as well as endemic plant species richness. The suitable habitat for P. setaceum is calculated to cover 34.7% of the surface of La Palma. In open ecosystems at low to mid elevations, where native ecosystems are already under pressure by land use and human activities, the spread of the invader will likely lead to additional threats to endemic plant species. Forest ecosystems (e.g., broadleaved evergreen and coniferous forests) are not likely to be affected by the spread of P. setaceum because of its heliophilous nature. Our projection of suitable habitat of P. setaceum within ecosystems and PAs on La Palma supports conservationists and policymakers in prioritizing management and control measures and acts as an example for the potential threat of this graminoid invader on other islands. ; This project has received funding from the European Union's Horizon 2020 research and innovation program ECOPOTENTIAL under grant agreement No 641762. This publication was funded by the German Research Foundation (DFG) and the University of Bayreuth in the funding program Open Access Publishing.

Distribution, status and conservation of the Houbara Bustard Chlamydotis undulata fuertaventurae Rothschild & Hurtert, 1894, in the Canary Islands, November-December 1994. This paper presents the results of census of the Canarian Houbara, which for the first time the total area occupied by this subspecies, Houbaras were detected only in Fuerteventura, Lanzarote and Graciosa. A total of 379 birds were recorded (33 from vehicles, 16 outside the transects, and a minimum of 330 inside the censusing belt), from which we estimated a total population of 527 birds: 18 in Graciosa, 268 in Lanzarote and 241 in Fuerteventura. Although the species scems to reach in the Canarian archipelago the highest density recorded for its whole geographical distribution, this island population is threathened by current loss and alteration of their habitat. ; Distribución, estatus y conservación de la Avutarda Hubara Chlamydotis undulata fuertaventurae Rothschild & Hartert, 1894, en las islas Canarias (noviembre-diciembre 1994). En el presente trabajo se presentan los resultados de un censo que cubre por primera vez toda el área de distribución de la Avutarda Hubara Canaria. Se detectaron hubaras en Fuerteventura, Lanzarote y Graciosa, contabilizándose un total de 379 ejemplares, 33 desde vehículos, 16 fuera de los transectos y un mínimo de 330 dentro de los transectos. Se ha estimado una población global constituida por 527 aves: 18 en Graciosa, 268 en Lanzarote y 241 en Fuerteventura. Probablemente, la densidad de aves registrada en la población canaria es la más elevada que se conoce para la especie. No obstante, la degradación y la destrucción del hábitat amenazan seriamente la conservación de esta subespecie insular. ; We are very grateful to K. W. Emmerson (Ornistudio S. L.) for his information on previous censuses, and to P. Jordano for his statistical assistance. Jacinto Barquín helped us with the mapping programs. D. Brooks revised and improved an early draft of the manuscript. We also thank the Instituto Nacional de Meteorología (Canarias Orientales). This work was supported by the Viceconsejería de Medio Ambiente of the Canary Island government. ; Peer reviewed

Aim: Rarity—an important measure for conservation biogeography—can vary over many orders of magnitude. However, it is unclear which regional-scale abiotic conditions drive processes affecting rarity of endemic species on islands. To support conservation efforts, we (1) assess the main abiotic drivers of endemic rarity, (2) determine how well existing protected areas (PAs) coincide with hotspots of endemic rarity and (3) introduce and evaluate a new hypervolume-based rarity estimator. Location: La Palma (Canary Islands). Methods: We recorded all present endemic vascular plant species in 1,212 plots covering the entire island. We calculated endemic rarity (corrected range-rarity richness for endemics) using a rarity estimation approach based on kernel density estimations (hypervolume approach). We performed a sensitivity analysis based on multiple linear regressions and relative importance estimations of environmental drivers to estimate the performance of the hypervolume-based rarity estimation compared to standard methods (occurrence frequency, convex hulls, alpha hulls). Results: Climate variables (mean annual temperature, climatic rarity, precipitation variability) best explained archipelago endemic (AE) and single-island endemic (SIE) rarity. Existing PAs covered the majority of AE and SIE rarity, especially national and natural parks as well as the Natura 2000 sites. In our study system, hypervolumes performed better than standard measures of range size. Main conclusion: Both AE and SIE rarity on La Palma show a clear spatial pattern, with hotspots of endemic rarity found at high elevations and in rare climates, presumably owing to geographical and climatic constraints and possibly anthropogenic pressure (e.g., land use, introduced herbivores, fire). Areas of high rarity estimates coincide with the distribution and extent of PAs on La Palma, especially since the recent addition of the Natura 2000 sites. The hypervolume approach is a promising tool to estimate species range sizes, and can be applied on all scales where point/plot data are available. ; European Union ; Elite Network of Bavaria

The taxonomy of Procellariiformes, particularly petrels and shearwaters, is still unresolved. The Manx shearwater Puffinus puffinus is one of the best studied seabirds worldwide. Most of the information known on this seabird is focused on the northern core populations where the species is abundant. However, the species shows a high number of peripheral populations, which are extremely small and difficult to study in comparison to central populations. Using an integrative approach, we provided significant evidence of phenological, morphological, acoustic, plumage colour and genetic differentiation of the Canarian Manx shearwaters (the most southern population) from the northern breeding colonies, which is compatible with a long period of isolation. Birds from the Canary Islands breed around 2–3 months earlier, are smaller and lighter and show darker underwing plumage than those from northern populations. In addition, Canarian call features are different from the northern populations. Finally, genetic analyses of the mitochondrial control region indicate an incipient genetic differentiation of Canarian Manx shearwaters from the other breeding populations. The Canarian population holds a small number of breeding colonies and it is declining, so accurate taxonomic recognition critically affects conservation efforts. For all the aforementioned reasons, we propose to rank the Canarian breeding population as a new taxon by presenting the formal description of a new subspecies Puffinus puffinus canariensis ssp. nov. ; This study was partially funded by the Canary Islands' Ornithology and Natural History Group (GOHNIC). JCI was funded by the Spanish Ministry of Science, Innovation and Universities (PGC2018-097575-B-I00) and by a GRUPIN research grant from the Regional Government of Asturias (IDI/2018/000151)