Browsing by Author "Arnedo, Miquel A."
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- Building a robust, densely-sampled spider tree of life for ecosystem researchPublication . Macías-Hernández, Nuria; Domènech, Marc; Cardoso, Pedro; Emerson, Brent C.; Borges, Paulo A. V.; Lozano-Fernandez, Jesús; Paulo, Octávio S.; Vieira, Ana; Enguídanos, Alba; Rigal, François; Rosário, Isabel Amorim do; Arnedo, Miquel A.Phylogenetic relatedness is a key diversity measure for the analysis and understanding of how species and communities evolve across time and space. Understanding the nonrandom loss of species with respect to phylogeny is also essential for better-informed conservation decisions. However, several factors are known to influence phylogenetic reconstruction and, ultimately, phylogenetic diversity metrics. In this study, we empirically tested how some of these factors (topological constraint, taxon sampling, genetic markers and calibration) affect phylogenetic resolution and uncertainty. We built a densely sampled, species-level phylogenetic tree for spiders, combining Sanger sequencing of species from local communities of two biogeographical regions (Iberian Peninsula and Macaronesia) with a taxon-rich backbone matrix of Genbank sequences and a topological constraint derived from recent phylogenomic studies. The resulting tree constitutes the most complete spider phylogeny to date, both in terms of terminals and background information, and may serve as a standard reference for the analysis of phylogenetic diversity patterns at the community level. We then used this tree to investigate how partial data affect phylogenetic reconstruction, phylogenetic diversity estimates and their rankings, and, ultimately, the ecological processes inferred for each community. We found that the incorporation of a single slowly evolving marker (28S) to the DNA barcode sequences from local communities, had the highest impact on tree topology, closely followed by the use of a backbone matrix. The increase in missing data resulting from combining partial sequences from local communities only had a moderate impact on the resulting trees, similar to the difference observed when using topological constraints. Our study further revealed substantial differences in both the phylogenetic structure and diversity rankings of the analyzed communities estimated from the different phylogenetic treatments, especially when using non-ultrametric trees (phylograms) instead of time-stamped trees (chronograms). Finally, we provide some recommendations on reconstructing phylogenetic trees to infer phylogenetic diversity within ecological studies.
- A database of functional traits for spiders from native forests of the Iberian Peninsula and MacaronesiaPublication . Macías Hernández, Nuria; Ramos, Cândida; Domènech, Marc; Febles, Sara; Santos, Irene; Arnedo, Miquel A.; Borges, Paulo A. V.; Emerson, Brent C.; Cardoso, PedroThere is an increasing demand for databases including species trait information for biodiversity and community ecology studies. The existence of trait databases is useful for comparative studies within taxa or geographical regions, but there is low availability of databases for certain organisms. Here we present an open access functional trait database for spiders from Macaronesia and the Iberian Peninsula, recording several morphological and ecological traits related to the species life histories, microhabitat and trophic preferences.
- Drivers of diversity in Macaronesian spiders and the role of species extinctionsPublication . Cardoso, Pedro; Arnedo, Miquel A.; Triantis, Kostas A.; Borges, Paulo A. V.AIM To identify the biogeographical factors underlying spider species richness in the Macaronesian region and assess the importance of species extinctions in shaping the current diversity. LOCATION The European archipelagos of Macaronesia with an emphasis on the Azores and Canary Islands.
- For all audiences : Incorporating immature stages into standardised spider inventories has a major impact on the assessment of biodiversity patternsPublication . Domènech, Marc; Wangensteen, Owen S.; Enguídanos, Alba; Malumbres-Olarte, Jagoba; Arnedo, Miquel A.Although arthropods are the largest component of animal diversity, they are traditionally underrepresented in biological inventories and monitoring programmes. However, no biodiversity assessment can be considered informative without including them. Arthropod immature stages are often discarded during sorting, despite frequently representing more than half of the collected individuals. To date, little effort has been devoted to characterising the impact of discarding nonadult specimens on our diversity estimates. Here, we used a metabarcoding approach to analyse spiders from oak forests in the Iberian Peninsula, to assess (1) the contribution of juvenile stages to local diversity estimates, and (2) their effect on the diversity patterns (compositional differences) across assemblages. We further investigated the ability of metabarcoding to inform on abundance. We obtained 363 and 331 species as adults and juveniles, respectively. Including the species represented only by juveniles increased the species richness of the whole sampling in 35% with respect to those identified from adults. Differences in composition between assemblages were greatly reduced when immature stages were considered, especially across latitudes, possibly due to phenological differences. Moreover, our results revealed that metabarcoding data are to a certain extent quantitative, but some sort of taxonomic conversion factor may be necessary to provide accurate informative estimates. Although our findings do not question the relevance of the information provided by adult-based inventories, they also reveal that juveniles provide a novel and relevant layer of knowledge that, especially in areas with marked seasonality, may influence our interpretations, providing more accurate information from standardised biological inventories.
- Habitat filtering and inferred dispersal ability condition across‐scale species turnover and rarity in Macaronesian island spider assemblagesPublication . Malumbres-Olarte, Jagoba; Rigal, François; Girardello, Marco; Cardoso, Pedro; Crespo, Luís C.; Amorim, Isabel R.; Arnedo, Miquel A.; Boieiro, Mário; Carvalho, José Carlos; Carvalho, Rui; Gabriel, Rosalina; Lamelas-López, Lucas; López, Heriberto; Paulo, Octávio S.; Pereira, Fernando; Pérez‐Delgado, Antonio J.; Rego, Carla; Romeiras, Maria M.; Ros-Prieto, Alejandra; Oromí, Pedro; Vieira, Ana; Emerson, Brent C.; Borges, Paulo A. V.AIM: Habitat diversity has been linked to the diversity and structure of island communities, however, little is known about patterns and processes within habitats. Here we aim to determine the contributions of habitat type and inferred dispersal frequency to the differences in taxonomic structure between assemblages in the same island habitat. LOCATION: The Macaronesian archipelagos (Azores, Madeira, the Canary Islands and Cabo Verde). TAXON: Spiders (Araneae). METHODS: We established forest and dry habitat sites (each with five plots) on two islands per archipelago. We collected spiders using standardised sampling protocols. We tested the differences in beta diversity separately for each habitat and for each inferred category of ballooning (an aerial dispersal strategy) frequency across geographic scales through nested non-parametric permutational multivariate analyses of variance. We then tested whether ballooning and habitat influenced heterogeneity in species composition (dispersion in beta diversity) in the two habitat types. We analysed the effects of habitat and ballooning on species abundance distribution (SAD) and rarity by fitting Gambin models and evaluating the contribution of ballooning categories to SAD. RESULTS: Communities of the same archipelago and habitat were taxonomically more similar, and beta diversity increased with geographic scale, being greater in dry habitats. There was greater species replacement among assemblages in dry habitats than in forests, with greater differences for rare ballooners. There were no differences in SAD between habitats although dry habitat sites seemed to harbour more species with low abundances (rare species) than forests. MAIN CONCLUSIONS: Habitat type does not only condition the differences between spider assemblages of the same habitat but also the scale at which they occur. These differences may be determined by the heterogeneity in the physical structure of each habitat as well as how much this structure facilitates aerial dispersal (ballooning), and should be considered in theories/hypotheses on island community assembly as well as in conservation strategies.
- How Iberian are we? Mediterranean climate determines structure and endemicity of spider communities in Iberian oak forestsPublication . Malumbres-Olarte, Jagoba; Crespo, Luís C.; Domènech, Marc; Cardoso, Pedro; Moya-Laraño, Jordi; Ribera, Carles; Arnedo, Miquel A.Understanding the causes behind species richness and endemicity is fundamental to explain biodiversity and assist conservation management, especially in biodiversity hotspots like the Mediterranean Basin. Here we investigate the patterns in Iberian forest spider communities and the processes behind their assembly, by testing hypotheses about the effects of climate and habitat on species richness, endemicity and structure of communities at different spatial scales, and about how microhabitat and dispersal affect the level of endemicity of species. We studied 16 spider communities in Iberian Quercus forests from different climatic zones, applying a standardised sampling protocol. We examined the contribution of habitat, climate, and geography to the differences in the composition of spider communities across spatial scales using distance-based redundancy analysis models (dbRDA) and principal coordinates of neighbour matrices (PCNM). We assessed the effects of the same variables on the endemicity of communities (measured by a weighted index), and tested the correlation between the microhabitat and the ballooning frequency (obtained from bibliography), and the endemicity of species through generalised linear models. Spider communities formed two groups—one southern and one northern—based on similarity in species composition. Precipitation and temperature were inversely related with the number of species while geography and forest type explained the compositional similarities between communities at different spatial scales. Endemicity of communities increased with temperature and decreased with precipitation, whereas species endemicity decreased with ballooning frequency. Our findings illustrate how niche-related processes may drive spider diversity while dispersal determines species distribution and identity and, ultimately, community composition. From a conservation viewpoint, when maximising species richness is incompatible with prioritising endemicity, the criteria to follow may depend on the geographic scale at which decisions are made.
- Macaronesia as a Fruitful Arena for Ecology, Evolution, and Conservation BiologyPublication . Florencio, Margarita; Patiño, Jairo; Nogué, Sandra; Traveset, Anna; Borges, Paulo A. V.; Schaefer, Hanno; Amorim, Isabel R.; Arnedo, Miquel A.; Ávila, Sérgio P.; Cardoso, Pedro; Nascimento, Lea; Fernández-Palacios, José María; Gabriel, Sofia I.; Gil, Artur José Freire; Gonçalves, Vitor; Haroun, Ricardo J.; Illera, Juan Carlos; López-Darias, Marta; Martínez, Alejandro; Martins, Gustavo M.; Neto, Ana I.; Nogales, Manuel; Oromí, Pedro; Rando, Juan Carlos; Raposeiro, Pedro M.; Rigal, François; Romeiras, Maria M.; Silva, Luís; Valido, Alfredo; Vanderpoorten, Alain; Vasconcelos, Raquel; Santos, Ana M. C.Research in Macaronesia has led to substantial advances in ecology, evolution and conservation biology. We review the scientific developments achieved in this region, and outline promising research avenues enhancing conservation. Some of these discoveries indicate that the Macaronesian flora and fauna are composed of rather young lineages, not Tertiary relicts, predominantly of European origin. Macaronesia also seems to be an important source region for back-colonisation of continental fringe regions on both sides of the Atlantic. This group of archipelagos (Azores, Madeira, Selvagens, Canary Islands, and Cabo Verde) has been crucial to learn about the particularities of macroecological patterns and interaction networks on islands, providing evidence for the development of the General Dynamic Model of oceanic island biogeography and subsequent updates. However, in addition to exceptionally high richness of endemic species, Macaronesia is also home to a growing number of threatened species, along with invasive alien plants and animals. Several innovative conservation and management actions are in place to protect its biodiversity from these and other drivers of global change. The Macaronesian Islands are a well-suited field of study for island ecology and evolution research, mostly due to its special geological layout with 40 islands grouped within five archipelagos differing in geological age, climate and isolation. A large amount of data is now available for several groups of organisms on and around many of these islands. However, continued efforts should be made toward compiling new information on their biodiversity, to pursue various fruitful research avenues and develop appropriate conservation management tools.
- Taxonomic divergence and functional convergence in Iberian spider forest communities : Insights from beta diversity partitioningPublication . Carvalho, José Carlos; Malumbres-Olarte, Jagoba; Arnedo, Miquel A.; Crespo, Luís C.; Domenech, Marc; Cardoso, PedroAIM: The main aims were to determine: (a) the relative contribution of species replacement and richness difference from components to overall taxonomic (TD beta) and functional (FD beta) beta diversity of spider communities; (b) the degree to which TD beta and FD beta components can be explained by the environmental or geographic predictors; (c) whether FD beta components were lower than expected given the underlying TD beta variation. LOCATION: This study was carried out in 22 oak forest sites across the Iberian Peninsula. The area comprises two biogeographic regions, Eurosiberian (North) and Mediterranean (Centre and South). METHODS: Spiders were sampled using a standardized protocol. A species x traits matrix was constructed. Total taxonomic (TD beta(total)) and total functional (FD beta(total)) beta diversity were calculated, by pairwise comparisons, and partitioned into their replacement (beta(repl)) and richness difference (beta(rich)) components. Mantel tests were used to relate taxonomic and functional dissimilarity with environmental and geographic distances. A spatial eigenfunction model was constructed and the variation in TD beta and FD beta explained by environment and geographic predictors was quantified. Null models were used to test if FD beta was higher or lower than expected given TD beta. RESULTS: beta(repl) was the dominant component contributing to 84.2% and 72.8% for TD beta(total) and FD beta(total), respectively. TD beta(total) and FD beta(total) (and their replacement components) were higher between- than within-biogeographic regions. TD beta(total) and TD beta(repl) were positively correlated with environmental and geographic distances, even when controlling for a biogeographic effect, but their functional counterparts were only correlated with environmental distance. Variation partitioning showed that pure environmental and spatially structured environmental effects had a small contribution to beta diversity, except for TD beta(rich). The observed slopes of the regressions of FD beta(total) and FD beta(repl) in relation to environmental distance were slower than the null model expectations. MAIN CONCLUSIONS: Spider assemblage variation was mainly determined by the replacement, and not the net loss, of species and traits. TD beta was influenced by niche filtering and dispersal limitation, whereas FD beta was mainly generated by niche filtering. A high level of functional convergence among spider communities, despite the high taxonomic divergence, revealed the signal of replacement of species performing similar functions across sites.
- What DNA barcodes reveal : microhabitat preference, hunting strategy and dispersal ability drive genetic variation across Iberian spider speciesPublication . Domènech, Marc; Malumbres-Olarte, Jagoba; Enguídanos, Alba; Múrria, Cesc; Arnedo, Miquel A.The current rate of species loss calls for immediate actions to preserve biodiversity and ecosystem functioning. Cataloguing species richness and composition, and revealing how diversity is geographically distributed are the first steps towards designing efficient conservation strategies. Here, we aim to determine diversity patterns and potential drivers of taxonomic and genetic diversity and population structure of Iberian spiders. We used a community level perspective, analysing more than 3000 DNA barcode sequences representing ~370 spider species dwelling in white-oak forest habitats across the Spanish National Park network. By combining and comparing morphological and DNA barcode-based species delimitation methods, we assessed their performance and identified putative factors behind cases of incongruence. Our findings uncovered potential overlooked diversity as suggested by the geographic patterns of genetic variation and put a red flag on those taxa that may be undergoing overlooked evolutionary or ecological processes. Spider functional traits associated with foraging strategy, microhabitat preference, ballooning ability and circadian activity explained the observed patterns of population structure across species but did not explain variation in genetic diversity. Overall, our study represents a major step forward in the understanding of large-scale diversity patterns in Iberian spiders at the community level and provides relevant information to guide future conservation strategies of the so-far largely overlooked invertebrate diversity.