A review of the combination among global change factors in forests, shrublands and pastures of the Mediterranean Region: Beyond drought effects

Doblas-Miranda, E., Alonso, R., Arnan, X., Bermejo, V., Brotons, L., de las Heras, J., Estiarte, M., Hódar, J.A., Llorens, P., Lloret, F., López-Serrano, F.R., Martínez-Vilalta, J., Moya, D., Peñuelas, J., Pino, J., Rodrigo, A., Roura-Pascual, N., Valladares, F., Vilà, M., Zamora, R., Retana, J. (2017) A review of the combination among global change factors in forests, shrublands and pastures of the Mediterranean Region: Beyond drought effects. Global and Planetary Change. 148: 42-54.
Link
Doi: 10.1016/j.gloplacha.2016.11.012

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Climate Change Could Negate Positive Tree Diversity Effects on Forest Productivity: A Study Across Five Climate Types in Spain and Canada

Paquette, A., Vayreda, J., Coll, L., Messier, C., Retana, J. (2017) Climate Change Could Negate Positive Tree Diversity Effects on Forest Productivity: A Study Across Five Climate Types in Spain and Canada. Ecosystems. : 1-11.
Link
Doi: 10.1007/s10021-017-0196-y

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Relationships among taxonomic, functional, and phylogenetic ant diversity across the biogeographic regions of Europe

Arnan X., Cerdá X., Retana J. (2016) Relationships among taxonomic, functional, and phylogenetic ant diversity across the biogeographic regions of Europe. Ecography. : 0-0.
Link
Doi: 10.1111/ecog.01938

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Understanding how different biodiversity components are related across different environmental conditions is a major goal in macroecology and conservation biogeography. We investigated correlations among alpha and beta taxonomic (TD), phylogenetic (PD), and functional diversity (FD) in ant communities in the five biogeographic regions most representative of western Europe; we also examined the degree of niche conservatism. We combined data from 349 ant communities composed of 154 total species, which were characterized by 10 functional traits and by phylogenetic relatedness. We computed TD, PD, and FD using the Rao quadratic entropy index, which allows each biodiversity component to be partitioned into α and β diversity within the same mathematical framework. We ran generalized least squares and multiple matrix regressions with randomization to investigate relationships among the diversity components. We used Pagel's λ test to explore niche conservatism in each biogeographic region. At the alpha scale, TD was consistently, positively related to PD and FD, although the strength and scatter of this relationship changed among the biogeographic regions. Meanwhile, PD and FD consistently matched up across regions. Accordingly, we found similar degrees of niche conservatism across regions. Nonetheless, these alpha-scale relationships had low coefficients of determination. At the beta scale, the three diversity components were highly correlated across all regions (especially TD and FD, as well as PD and FD). Our results imply that the different diversity components, and especially PD and FD, are consistently related across biogeographic regions and analytical scale. However, the alpha-scale relationships were quite weak, suggesting environmental factors might influence the degree of association among diversity components at the alpha level. In conclusion, conservation programs should seek to preserve functional and phylogenetic diversity in addition to species richness, and this approach should be applied universally, regardless of the biogeographic locations of the sites to be protected. © 2016 Nordic Society Oikos.

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GlobalAnts: A new database on the geography of ant traits (Hymenoptera: Formicidae)

Parr, C.L., Dunn, R.R., Sanders, N.J., Weiser, M.D., Photakis, M., Bishop, T.R., Fitzpatrick, M.C., Arnan, X., Baccaro, F., Brandão, C.R.F., Chick, L., Donoso, D.A., Fayle, T.M., Gómez, C., Grossman, B., Munyai, T.C., Pacheco, R., Retana, J., Robinson, A., Sagata, K., Silva, R.R., Tista, M., Vasconcelos, H., Yates, M., Gibb, H. (2016) GlobalAnts: A new database on the geography of ant traits (Hymenoptera: Formicidae). Insect Conservation and Diversity. : 0-0.
Link
Doi: 10.1111/icad.12211

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Synergies Between Forest Biomass Extraction for Bioenergy and Fire Suppression in Mediterranean Ecosystems: Insights from a Storyline-and-Simulation Approach

Regos A., Aquilué N., López I., Codina M., Retana J., Brotons L. (2016) Synergies Between Forest Biomass Extraction for Bioenergy and Fire Suppression in Mediterranean Ecosystems: Insights from a Storyline-and-Simulation Approach. Ecosystems. 19: 786-802.
Link
Doi: 10.1007/s10021-016-9968-z

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Increases in fire impacts over many regions of the world have led to large-scale investments in fire-suppression efforts. There is increasing recognition that biomass extraction for energy purposes may become an important forest-management practice in fire-prone ecosystems. However, at present, very few studies have explicitly assessed biomass extraction as a fuel treatment at landscape scale. Here, we use a landscape fire-succession model in Catalonia (NE Spain) to quantitatively evaluate the potential effects of a biomass extraction-based strategy on essential fire-regime attributes after considering different levels of fire suppression, biomass extraction intensity, and spatial allocation of such efforts. Our simulations indicated that the effectiveness (area suppressed in relation to expected area to burn) at suppressing wildfires was determined by extraction intensity, spatial allocation of the extraction effort, and the fire-suppression levels involved. Indeed, the highest suppressed-area values were found with lower harvesting intensities, especially under high fire-suppression capabilities and strategies focused on bioenergy goals (figures close to 0.7). However, the leverage (area suppressed in relation to managed area) was higher when the treatments were based on the fire-prevention strategy and focused on high-fire-risk areas (up to 0.45) than with treatment designed for energy reasons (lower than 0.15). We conclude that biomass extraction for energy purposes has the potential to induce changes in fire regimes and can therefore be considered a cost-effective landscape-level fuel-reduction treatment. However, our results suggest that large-scale biomass extraction may be needed if significant changes in fire regimes are to be expected. © 2016, Springer Science+Business Media New York.

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Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators

Reverté S., Retana J., Gómez J.M., Bosch J. (2016) Pollinators show flower colour preferences but flowers with similar colours do not attract similar pollinators. Annals of Botany. 118: 249-257.
Link
Doi: 10.1093/aob/mcw103

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Background and aims Colour is one of the main floral traits used by pollinators to locate flowers. Although pollinators show innate colour preferences, the view that the colour of a flower may be considered an important predictor of its main pollinators is highly controversial because flower choice is highly context-dependent, and initial innate preferences may be overridden by subsequent associative learning. Our objective is to establish whether there is a relationship between flower colour and pollinator composition in natural communities. Methods We measured the flower reflectance spectrum and pollinator composition in four plant communities (85 plant species represented by 109 populations, and 32 305 plant-pollinator interactions in total). Pollinators were divided into six taxonomic groups: bees, ants, wasps, coleopterans, dipterans and lepidopterans. Key Results We found consistent associations between pollinator groups and certain colours. These associations matched innate preferences experimentally established for several pollinators and predictions of the pollination syndrome theory. However, flowers with similar colours did not attract similar pollinator assemblages. Conclusions The explanation for this paradoxical result is that most flower species are pollination generalists. We conclude that although pollinator colour preferences seem to condition plant-pollinator interactions, the selective force behind these preferences has not been strong enough to mediate the appearance and maintenance of tight colour-based plant-pollinator associations. © 2016 The Author 2016.

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Edge influence on diversity of orchids in Andean cloud forests

Sánchez E.P., Armenteras D., Retana J. (2016) Edge influence on diversity of orchids in Andean cloud forests. Forests. 7: 0-0.
Link
Doi: 10.3390/f7030063

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Cloud forests harbor high levels of orchid diversity. However, due to the high fragmentation of these forests in the Andes, combined with the pressure for new agricultural land, orchid diversity is highly threatened. Despite this worrying scenario, few studies have assessed the effects of habitat loss specifically on orchid assemblages in the Andes. The aim of this study was to analyze the edge effect on orchids in cloud forest fragments of varying size. We measured forest structure, neighboring land cover and edge effect on orchid abundance, species richness and beta-diversity, by sampling assemblages along edge-to-interior transects in six different sized Andean (southwest Colombia) forest remnants. We recorded 11,127 stem-individuals of orchids in 141 species. Within the forest, edges sustained equal or more species than interior plots. Our results revealed neither patch metrics nor forest structure showed any significant association to orchid diversity at any scale. Nonetheless, from our observations in composition, the type of neighboring cover, particularly pastures, negatively influences interior species (richness and composition) in larger reserves. This might be due to the fact that some species found in interior plots tend to be confined, with sporadic appearances in regeneration forest and are very scarce or absent in pastures. Species richness differed significantly between matrix types. Our results suggest that (1) orchid diversity shows spatial variability in response to disturbances, but the response is independent from forest structure, patch size and patch geometry; (2) orchid communities are negatively affected by covers, and this pattern is reflected in reduced richness and high species turnover; (3) orchid richness edge effect across a pasture-interior gradient. Two forest management implications can be discerned from our results: (1) management strategies aiming to reduce edge effects may focus on improvement regeneration conditions around pasture lands; and (2) local scale management and conservation activities of natural forests in cloud forests will favor small reserves that harbor high levels of richness. © 2016 by the authors.

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Anthropogenic-driven rapid shifts in tree distribution lead to increased dominance of broadleaf species

Vayreda, J., Martinez-Vilalta, J., Gracia, M., Canadell, J.G., Retana, J. (2016) Anthropogenic-driven rapid shifts in tree distribution lead to increased dominance of broadleaf species. Global Change Biology. 22: 3984-3995.
Link
Doi: 10.1111/gcb.13394

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National and regional relationships of carbon storage and tropical biodiversity

Armenteras D., Rodríguez N., Retana J. (2015) National and regional relationships of carbon storage and tropical biodiversity. Biological Conservation. 192: 378-386.
Link
Doi: 10.1016/j.biocon.2015.10.014

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Tropical forests host the highest levels of biodiversity and maintain some of the largest carbon stocks of all terrestrial ecosystems. Policies resulting from the United Nations Framework Convention on Climate Change (UNFCC) for forest-based climate change mitigation (e.g., Reducing Emissions from Deforestation and forest Degradation (REDD. +)) have been considered win-win solutions for both C storage and biodiversity conservation. Win-win solutions are indeed apparent when there is geographical overlap of high carbon density forests with high biodiversity, as suggested by many global studies. However, strong congruence between high carbon storage and biodiversity at the national and subnational levels is less obvious. To improve national policies and expectations of REDD. + outcomes, it is necessary to account for the potential risks of relocating deforestation activities from high-carbon areas to low-carbon areas, as such relocation may negatively affect high-biodiversity habitats. Using a combined dataset of global and national biodiversity and C storage, we examined whether the optimization of carbon and biodiversity is, as suggested, a win-win situation. We identified hotspots of C storage and of biodiversity within Colombia and the demographic and land use factors that affect the spatial distribution of the current patterns of biodiversity and C. We also identified and mapped two additional forest carbon and biodiversity relationships (areas with high carbon and low biodiversity and areas with low carbon and high biodiversity) that represented relevant conservation trade-offs at national and subnational levels. Our results suggest that, although C storage and biodiversity hotspots still overlap nationally and subnationally, the relationship between these two types of hotspots is weaker than that at the global level. Additionally, areas where high carbon and high biodiversity do not overlap are more extensive than potential win-win areas. Simultaneous carbon and biodiversity conservation is not as straightforward as it appears to be at the global level. Countries must swiftly identify areas where unintentional negative biodiversity consequences may result from national REDD. + strategies, and future research should identify the factors that affect C storage and biodiversity both at the national and subnational levels. © 2015 Elsevier Ltd.

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Partitioning the impact of environment and spatial structure on alpha and beta components of taxonomic, functional, and phylogenetic diversity in European ants

Arnan X., Cerdá X., Retana J. (2015) Partitioning the impact of environment and spatial structure on alpha and beta components of taxonomic, functional, and phylogenetic diversity in European ants. PeerJ. 2015: 0-0.
Link
Doi: 10.7717/peerj.1241

Abstract:

We analyze the relative contribution of environmental and spatial variables to the alpha and beta components of taxonomic (TD), phylogenetic (PD), and functional (FD) diversity in ant communities found along different climate and anthropogenic disturbance gradients across western and central Europe, in order to assess the mechanisms structuring ant biodiversity. To this aim we calculated alpha and beta TD, PD, and FD for 349 ant communities, which included a total of 155 ant species; we examined 10 functional traits and phylogenetic relatedness. Variation partitioning was used to examine how much variation in ant diversity was explained by environmental and spatial variables. Autocorrelation in diversity measures and each trait's phylogenetic signal were also analyzed.We found strong autocorrelation in diversity measures. Both environmental and spatial variables significantly contributed to variation in TD, PD, and FD at both alpha and beta scales; spatial structure had the larger influence. The different facets of diversity showed similar patterns along environmental gradients. Environment explained a much larger percentage of variation in FD than in TD or PD. All traits demonstrated strong phylogenetic signals. Our results indicate that environmental filtering and dispersal limitations structure all types of diversity in ant communities. Strong dispersal limitations appear to have led to clustering of TD, PD, and FD in western and central Europe, probably because different historical and evolutionary processes generated different pools of species. Remarkably, these three facets of diversity showed parallel patterns along environmental gradients. Trait-mediated species sorting and niche conservatism appear to structure ant diversity, as evidenced by the fact that more variation was explained for FD and that all traits had strong phylogenetic signals. Since environmental variables explained much more variation in FD than in PD, functional diversity should be a better indicator of community assembly processes than phylogenetic diversity. © 2015 Arnan et al.

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