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- A comparative analysis of terrestrial arthropod assemblages from a relict forest unveils historical extinctions and colonization differences between two oceanic islandsPublication . Boieiro, Mário; Matthews, Thomas J.; Rego, Carla; Crespo, Luis; Aguiar, Carlos A. S.; Cardoso, Pedro; Rigal, François; Silva, Isamberto; Pereira, Fernando; Borges, P.A.V.; Serrano, ArturDuring the last few centuries oceanic island biodiversity has been drastically modified by human-mediated activities. These changes have led to the increased homogenization of island biota and to a high number of extinctions lending support to the recognition of oceanic islands as major threatspots worldwide. Here, we investigate the impact of habitat changes on the spider and ground beetle assemblages of the native forests of Madeira (Madeira archipelago) and Terceira (Azores archipelago) and evaluate its effects on the relative contribution of rare endemics and introduced species to island biodiversity patterns. We found that the native laurel forest of Madeira supported higher species richness of spiders and ground beetles compared with Terceira, including a much larger proportion of indigenous species, particularly endemics. In Terceira, introduced species are well-represented in both terrestrial arthropod taxa and seem to thrive in native forests as shown by the analysis of species abundance distributions (SAD) and occupancy frequency distributions (OFD). Low abundance range-restricted species in Terceira are mostly introduced species dispersing from neighbouring man-made habitats while in Madeira a large number of true rare endemic species can still be found in the native laurel forest. Further, our comparative analysis shows striking differences in species richness and composition that are due to the geographical and geological particularities of the two islands, but also seem to reflect the differences in the severity of human-mediated impacts between them. The high proportion of introduced species, the virtual absence of rare native species and the finding that the SADs and OFDs of introduced species match the pattern of native species in Terceira suggest the role of man as an important driver of species diversity in oceanic islands and add evidence for an extensive and severe human-induced species loss in the native forests of Terceira.
- Consistency of impact assessment protocols for non-native speciesPublication . González-Moreno, Pablo; Lazzaro, Lorenzo; Vilà, Montserrat; Preda, Cristina; Adriaens, Tim; Bacher, Sven; Brundu, Giuseppe; Copp, Gordon H.; Essl, Franz; García-Berthou, Emili; Katsanevakis, Stelios; Moen, Toril Loennechen; Lucy, Frances E.; Nentwig, Wolfgang; Roy, Helen E.; Srėbalienė, Greta; Talgø , Venche; Vanderhoeven, Sonia; Andjelković, Ana; Arbačiauskas, Kęstutis; Auger-Rozenberg, Marie-Anne; Bae, Mi-Jung; Bariche, Michel; Boets, Pieter; Boieiro, Mário; Borges, Paulo; Canning-Clode, João; Cardigos, Federico; Chartosia, Niki; Cottier-Cook, Elizabeth Joanne; Crocetta, Fabio; D'hondt, Bram; Foggi, Bruno; Follak, Swen; Gallardo, Belinda; Gammelmo, Øivind; Giakoumi, Sylvaine; Giuliani, Claudia; Guillaume, Fried; Jelaska, Lucija Šerić; Jeschke, Jonathan M.; Jover, Miquel; Juárez-Escario, Alejandro; Kalogirou, Stefanos; Kočić, Aleksandra; Kytinou, Eleni; Laverty, Ciaran; Lozano, Vanessa; Maceda-Veiga, Alberto; Marchante, Elizabete; Marchante, Hélia; Martinou, Angeliki F.; Meyer, Sandro; Minchin, Dan; Montero-Castaño, Ana; Morais, Maria Cristina; Morales-Rodriguez, Carmen; Muhthassim, Naida; Nagy, Zoltán Á.; Ogris, Nikica; Onen, Huseyin; Pergl, Jan; Puntila, Riikka; Rabitsch, Wolfgang; Ramburn, Triya Tessa; Rego, Carla; Reichenbach, Fabian; Romeralo, Carmen; Saul, Wolf-Christian; Schrader, Gritta; Sheehan, Rory; Simonović, Predrag; Skolka, Marius; Soares, António Onofre; Sundheim, Leif; Tarkan, Ali Serhan; Tomov, Rumen; Tricarico, Elena; Tsiamis, Konstantinos; Uludağ, Ahmet; van Valkenburg, Johan; Verreycken, Hugo; Vettraino, Anna Maria; Vilar, Lluís; Wiig, Øystein; Witzell, Johanna; Zanetta, Andrea; Kenis, MarcStandardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.