Percorrer por autor "Silva, Isamberto"
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- Assessing the conservation status of the strict endemic Desertas wolf spider, Hogna ingens (Araneae, Lycosidae)Publication . Crespo, Luís C.; Silva, Isamberto; Borges, Paulo A. V.; Cardoso, PedroThe Desertas Islands (Madeira, Portugal) are the sole home of one of the largest and rarest wolf spiderspecies, Hogna ingens (Blackwall 1857) (Araneae, Lycosidae). Despite its size, it inhabits a single valleyin the North of the Deserta Grande Island, Vale da Castanheira, currently invaded by the herb Phalarisaquatica. This invasive species competes with the native flora and was subject to several eradicationexperiments, namely through fire and chemicals. The objectives of this work were to: (1) estimate thecurrent distribution and abundance of H. ingens and respective trends; (2) evaluate the impact of theinvasive plant and eradication methods on the spider population; (3) suggest future measures for therecovery of the species; and (4) evaluate its conservation status according to the IUCN criteria. The current distribution of H. ingens covers 23 ha, a recent reduction from its original 83 ha, correspond-ing to the entire Vale da Castanheira. A total of 4447 and 4086 adults and 71,832 and 24,635 juvenileswere estimated to live in the valley during 2011 and 2012, respectively. We found a significant negativeimpact of P. aquatica cover on the presence and abundance of H. ingens and that chemical treatmentspecifically directed towards the invasive plant species may be the only way to effectively recover thespider's habitat. We suggest (1) regular monitoring; (2) extend chemical treatments; (3) ex-situ conserva-tion with future reintroduction of adults. Based on the current area of occupancy (AOO) of H. ingens and itsrecent decline in both AOO and number of individuals, it was recently classified as Critically Endangeredby IUCN and we suggest its urgent inclusion in the Habitats Directive species lists.
- Ground beetles (Coleoptera: Carabidae) of the Desertas Islands (Madeira archipelago, Portugal): description of a new subspecies and faunistic notesPublication . Serrano, Artur; Aguiar, Carlos; Cardoso, Pedro; Pereira, Fernando; Padro e Castro, Catarina; Rego, Carla; Silva, Isamberto; Canelas Boieiro, Mário RuiABSTRACT: We update the knowledge on the ground beetle fauna (Coleoptera: Carabidae) of the Desertas Islands and provide novel information on species distribution in the three islands (Ilhéu Chão, Deserta Grande and Bugio) following two entomological missions carried out in 2011 and 2012. An annotated checklist of the 33 species and subspecies known to occur in the Desertas Islands is presented, jointly with data on their distribution and ecology. Philorhizus melanocephalus (Dejean) is recorded for the first time for Madeira archipelago, four other taxa are new records for the Desertas Islands: Apotomus chaudoirii Wollaston, Ocys harpaloides (Serville), Paradromius (Manodromius) insularis oceanicus (Wollaston) and Syntomus fuscomaculatus (Motschulsky) and several species are for the first time recorded for specific Desertas’ islands. Furthermore, a new subspecies of the genus Orthomus Chaudoir, 1838 sampled by direct collection in Bugio is described: O. (Nesorthomus) bedelianus isambertoi Serrano & Boieiro, ssp. nov. with its habitus and aedeagus illustrated. The new subspecies is compared with the closely related Orthomus (Nesorthomus) bedelianus bedelianus (Lutshnik) from Madeira Island. A historical review of the research on the ground beetles of the Desertas Islands is presented, along with considerations on beetle species rarity and the conservation measures needed to protect them. This information will be helpful to support biodiversity conservation management in the Desertas Islands.
- New data on the fruit flies (Drosophilidae) of Madeira archipelago with notes on the ecology of the endemic Drosophila madeirensis MonclúsPublication . Rego, Carla; Aguiar, António F.; Cravo, Délia; Boieiro, Mário; Silva, Isamberto; Castro, Catarina P.; Menezes, Dilia; Serrano, Artur R. M.The first findings of drosophilids from Desertas and Porto Santo islands (Madeira archipelago) are reported and the knowledge on the abundance and distribution of the endemic Drosophila madeirensis Monclús is updated. This Madeiran endemic was found associated with forest habitats, but was not exclusive of Laurisilva. Furthermore, the finding of widespread populations with moderate abundance indicates that presently this species is not endangered. Finally, we provide an updated checklist of the family Drosophilidae occurring in the Madeira archipelago.
- Rapid biodiversity assessment, faunistics and description of a new spider species (Araneae) from Desertas Islands and Madeira (Portugal)Publication . Crespo, Luís C.; Silva, Isamberto; Borges, Paulo A. V.; Cardoso, PedroEl conocimiento actual de la araneofauna de las Islas Desertas (Madeira) se puede considerar como deficiente, con sólo 11 especies registradas. Con la finalidad de cubrir este vacío se efectuaron diversas expediciones durante 2011 y 2012, en las cuales se realizaron muestreos estandarizados y capturas manuales. Como era de esperar para islas pequeñas y aisladas, las estimas de la riqueza de especies por hectárea son relativamente bajas, oscilando entre 19 a 23 especies. La lista de especies local se há incrementado hasta 57 especies, de las cuales 11 podrían ser nuevas para la ciencia, incluyendo una especie nueva de Typhochrestus Simon, 1884, endémica del archipiélago de Madeira, aquí descrita. También se describe el macho, hasta ahora desconocido, de Zimirina lepida (Blackwall, 1859). La familia Ochyroceratidae Fage, 1912 es citada por primera vez de un hábitat nativo en Europa.
- Species conservation profiles of endemic spiders (Araneae) from Madeira and Selvagens archipelagos, PortugalPublication . Cardoso, Pedro; Crespo, Luís C.; Silva, Isamberto; Borges, Paulo A. V.; Boieiro, MárioBACKGROUND: The North Atlantic archipelagos of Madeira and Selvagens present a unique biological diversity including, presently, 56 endemic spider species. Several recent projects provide valuable information on their distribution across most islands and habitats. To date, the only endemic spider assessed according to the IUCN Red List criteria is Hogna ingens. The objective of this paper is to assess all remaining endemic species and advise on possible future conservation actions critical for the survival of endangered species. NEW INFORMATION: Seven species were found to have a continuing decline in either range or population size. Their decline can be mostly attributed to habitat destruction or degradation, invasive plant species that reduce quality of habitat, forest fires at high mountain regions and possible competition for resources from invasive congeners. The tetragnathid M. barreti is considered as possibly extinct due to the suspected impact of a competing species. Although most endemic spiders from the Madeira and Selvagens archipelagos have relatively low extinction risk due to the good condition and protection of the laurisilva forests where many live, there are a number of species requiring urgent attention and protection measures. These include all cave and mountain-restricted species as well as those threatened by competing congeners or invasive plants. Extending current protected areas, restoring original habitats of threatened species and the control of invasive taxa should remain a priority for species survival.
- Standardised inventories of spiders (Arachnida, Araneae) of Macaronesia II : The native forests and dry habitats of Madeira archipelago (Madeira and Porto Santo islands)Publication . Malumbres-Olarte, Jagoba; Boieiro, Mário; Cardoso, Pedro; Carvalho, Rui; Crespo, Luís C.; Gabriel, Rosalina; Macías Hernández, Nuria; Paulo, Octávio S.; Pereira, Fernando; Rego, Carla; Ros Prieto, Alejandra; Silva, Isamberto; Vieira, Ana; Rigal, François; Borges, Paulo A. V.BACKGROUND: Here we present the data obtained from the samples collected as part of a large research project (MACDIV) which aims at understanding the drivers of spider (Araneae) community assembly in Macaronesian islands. To obtain the data, we applied the sampling protocol COBRA (Conservation Oriented Biodiversity Rapid Assessment), in twelve 50 m x 50 m native forest plots and five dry habitat plots on the island of Madeiraand in 5 dry habitat plots on the island of Porto Santo. Through this publication, we contribute to the knowledge of the arachnofauna of the Madeiran archipelago. NEW INFORMATION: From the samples that we collected, we obtained a total of 14,902 specimens, of which 49% were adults (7,263). We identified these specimens to 87 species and 18 morphospecies (undescribed), belonging to 26 families. Species of the family Linyphiidae dominated the samples, with 24 (morpho)species. Out of the 105 recorded (morpho)species, 34 were endemic, 26 native non-endemic, 22 introduced and 23 species of unknown origin. We report seven new records of possibly recently introduced species in the Madeiran archipelago. We also present 21 new records for Madeira island and 32 for Porto Santo (33 for the whole archipelago).