Species traits weakly involved in plant responses to landscape properties in Mediterranean grasslands

Bagaria G., Pino J., Rodà F., Guardiola M. (2012) Species traits weakly involved in plant responses to landscape properties in Mediterranean grasslands. Journal of Vegetation Science. 23: 432-442.
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Doi: 10.1111/j.1654-1103.2011.01363.x

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Questions: What is the role of landscape structure and dynamics, compared with climatic and geographic factors, in determining species frequencies of grassland plant specialists under habitat loss? Do species traits mediate the relationship between plant community composition and environmental variables? Location: The Mediterranean mountain grasslands of southern Catalonia (NE Iberian Peninsula), over an area of 100 × 20 km. Methods: Using redundancy analysis (RDA), we explored the association between frequency of broad plant specialists and both present and past habitat patterns in the landscape (i.e. habitat amount and reduction over the period 1956-2003), after accounting for the effect of geographical location and climate in 29 grassland patches. Then, we constructed a database of biological and ecological plant traits potentially related to population persistence, in order to assess the role of these traits in explaining the found association between species composition and environmental variables. We used a single, three-table ordination analysis (RLQ) of the species frequencies, environmental variables and species traits to relate species traits to environmental variables, after allowing for phylogenetic dependence of traits. Results: The main environmental gradient explaining species frequencies was climatic and geographic. Habitat amount in the current landscape significantly affected species frequencies, while habitat amount in the past landscape did not. A weak but significant association of species traits with environmental variables was detected. Taking into account the phylogenetic signal in plant traits did not change the results. Conclusions: Plant species in Mediterranean grasslands seem to respond quickly to landscape change, since no effect of past landscape structure was observed on current species frequencies. Moreover, plant traits did not play a major role in mediating species response to environmental variation in these grasslands. Our findings differ from those obtained in northern and central European grasslands, probably due to differences in methodology but also to the smaller contrast in environmental conditions between grasslands and the adjacent forests and scrub in Mediterranean landscapes. © 2011 International Association for Vegetation Science.

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Deconstructing the native-exotic richness relationship in plants

Bartomeus I., Sol D., Pino J., Vicente P., Font X. (2012) Deconstructing the native-exotic richness relationship in plants. Global Ecology and Biogeography. 21: 524-533.
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Doi: 10.1111/j.1466-8238.2011.00708.x

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Aim Classic theory suggests that species-rich communities should be more resistant to the establishment of exotic species than species-poor communities. Although this theory predicts that exotic species should be less diverse in regions that contain more native species, macroecological analyses often find that the correlation between exotic and native species richness is positive rather than negative. To reconcile results with theory, we explore to what extent climatic conditions, landscape heterogeneity and anthropogenic disturbance may explain the positive relationship between native and exotic plant richness. Location Catalonia (western Mediterranean region). Methods We integrated floristic records and GIS-based environmental measures to make spatially explicit 10-km grid cells. We asked whether the observed positive relationship between native and exotic plant richness (R 2= 0.11) resulted from the addition of several negative correlations corresponding to different environmental conditions identified with cluster analysis. Moreover, we directly quantified the importance of common causal effects with a structural equation modelling framework. Results We found no evidence that the relationship between native and exotic plant richness was negative when the comparison was made within environmentally homogeneous groups. Although there were common factors explaining both native and exotic richness, mainly associated with landscape heterogeneity and human pressure, these factors only explained 17.2% of the total correlation. Nevertheless, when the comparison was restricted to native plants associated with human-disturbed (i.e. ruderal) ecosystems, the relationship was stronger (R 2= 0.52) and the fraction explained by common factors increased substantially (58.3%). Main conclusions While our results confirm that the positive correlation between exotic and native plant richness is in part explained by common extrinsic factors, they also highlight the great importance of anthropic factors that - by reducing biotic resistance - facilitate the establishment and spread of both exotic and native plants that tolerate disturbed environments. © 2011 Blackwell Publishing Ltd.

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Projecting trends in plant invasions in Europe under different scenarios of future land-use change

Chytrý M., Wild J., Pyšek P., Jarošík V., Dendoncker N., Reginster I., Pino J., Maskell L.C., Vilà M., Pergl J., Kühn I., Spangenberg J.H., Settele J. (2012) Projecting trends in plant invasions in Europe under different scenarios of future land-use change. Global Ecology and Biogeography. 21: 75-87.
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Doi: 10.1111/j.1466-8238.2010.00573.x

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Aim Recent studies of plant invasions in habitat types across different climatic regions of Europe have made it possible to produce a European map of plant invasions. Parallel research led to the formulation of integrated scenarios of future socio-economic development, which were used to create spatially explicit scenarios of European land-use change for the 21st century. Here we integrate these two research lines and produce the first spatially explicit projections of plant invasions in Europe for the years 2020, 2050 and 2080. Location The European Union (except Bulgaria and Romania), Norway and Switzerland. Methods We used vegetation plots from southern, central and north-western Europe to quantify mean levels of invasion by neophytes (post-1500 alien plants) for forest, grassland, urban, arable and abandoned land. We projected these values on the land-use scenarios for 2020, 2050 and 2080, and constructed maps of future plant invasions under three socio-economic scenarios assuming: (1) deregulation and globalization, (2) continuation of current policies with standing regulations, and (3) a shift towards sustainable development. Results Under all scenarios an increase in the level of invasion was projected for north-western and northern Europe, and under the first two scenarios a decrease for some agricultural areas of eastern Europe where abandonment of agricultural land is expected. A net increase in the level of invasion over Europe was projected under scenarios 2 and 3. Main conclusions The polarization between more and less invaded regions is likely to increase if future policies are oriented on economic deregulation, which may result in serious future problems in some areas of Europe. However, an implementation of sustainability policies would not automatically restrict the spread of alien plants. Therefore invasions require specific policy approaches beyond the more general ones, which are currently on the policy agenda and were tested in the scenarios. © 2012 Blackwell Publishing Ltd.

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The role of past and present landscape on plant invasion in the Mediterranean coast

Basnou C, Iguzguiza J, Pino J (2012) The role of past and present landscape on plant invasion in the Mediterranean coast. NEOBIOTA 2012 Halting Biological Invasions in Europe: from Data to Decisions, 7th European Conference on Biological Invasions. Pontevedra. 12-14 Septembre. (comunicació oral).

Regional context affects native and alien plant species richness across habitat types

Gassó N., Pino J., Font X., Vilà M. (2012) Regional context affects native and alien plant species richness across habitat types. Applied Vegetation Science. 15: 4-13.
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Doi: 10.1111/j.1654-109X.2011.01159.x

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Question: How does large-scale context affect native and alien species richness across different habitat types? Location: Catalonia, NE Spain. Methods: We analysed a set of 5309 vegetation plots from the BDBC (Biodiversity Data Bank of Catalonia) database, organized following the UTM (Universal Transverse Mercator) 10 km × 10 km grid. Plots were assigned to the first or second hierarchy of EUNIS (European Nature Information System) habitat classification. For each plot, the number of native plants (including archaeophytes, i.e. alien plants introduced before 1500 ad) and neophytes (alien plants introduced after 1500 ad) was recorded. Neophytes were classified according their Raunkiaer's life form. For each UTM we selected eight predictors related to land cover composition, anthropogenic context and climate. The association of neophyte and native species richness with these predictor variables was explored by generalized linear mixed models for each terrestrial habitat type after controlling for plot area. Results: A total of 77 different neophyte species were found distributed among the eight habitat types with fitted models. Minimum adequate models on both neophyte and native species richness were highly variable. In general, native species richness responded more to climatic variables, while neophyte species richness was associated more with human landscape factors such as distance to main roads and, secondarily, cropland cover. Conclusions: Context factors defined on a large scale (10 km) have a significant effect on local native and neophyte species richness for many habitat types in Catalonia. Our results highlight the major influence of climatic context on native species richness and the influence of human landscape context on neophyte species richness in the study region. The inconsistency of results between habitat types suggests that this large-scale effect might be highly idiosyncratic and dependent on species ecology and life form. © 2011 International Association for Vegetation Science.

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Análisis del estado de invasión por especies exóticas en Cataluña.

Andreu J, Pino J (2012) Análisis del estado de invasión por especies exóticas en Cataluña. EEI 2012, 4º Congreso Nacional Sobre Especies Exóticas Invasoras. Pontevedra, 10-11 setembre (comunicació oral).

Les espècies exòtiques de Catalunya. Resum del projecte EXOCAT 2012.

Andreu J, Pino J, Basnou C, Guardiola M, Ordóñez JL (2012) Les espècies exòtiques de Catalunya. Resum del projecte EXOCAT 2012.  http://www20.gencat.cat/docs/DAR/MN_Medi_natural/MN10_Fauna_salvatge_autoctona/Fauna_invasora_medi_natural/EXOCAT_2012_def.pdf

Anàlisi en el marc del SITxell dels canvis en el paisatge (1956-2005) i de la seva repercussió en la conservació dels espais naturals protegits de la província de Barcelona

Pino J, Basnou C (2012) Anàlisi en el marc del SITxell dels canvis en el paisatge (1956-2005) i de la seva repercussió en la conservació dels espais naturals protegits de la província de Barcelona. Informe inèdit. Diputació de Barcelona. Area d’Espais Naturals.

Modelling invasive alien species distributions from digital biodiversity atlases. Model upscaling as a means of reconciling data at different scales

Marcer A., Pino J., Pons X., Brotons L. (2012) Modelling invasive alien species distributions from digital biodiversity atlases. Model upscaling as a means of reconciling data at different scales. Diversity and Distributions. 18: 1177-1189.
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Doi: 10.1111/j.1472-4642.2012.00911.x

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Aim: There is a wealth of information on species occurrences in biodiversity data banks, albeit presence-only, biased and scarce at fine resolutions. Moreover, fine-resolution species maps are required in biodiversity conservation. New techniques for dealing with this kind of data have been reported to perform well. These fine-resolution maps would be more robust if they could explain data at coarser resolutions at which species distributions are well represented. We present a new methodology for testing this hypothesis and apply it to invasive alien species (IAS). Location: Catalonia, Spain. Methods: We used species presence records from the Biodiversity data bank of Catalonia to model the distribution of ten IAS which, according to some recent studies, achieve their maximum distribution in the study area. To overcome problems inherent with the data, we prepared different correction treatments: three for dealing with bias and five for autocorrelation. We used the MaxEnt algorithm to generate models at 1-km resolution for each species and treatment. Acceptable models were upscaled to 10 km and validated against independent 10 km occurrence data. Results: Of a total of 150 models, 20 gave acceptable results at 1-km resolution and 12 passed the cross-scale validation test. No apparent pattern emerged, which could serve as a guide on modelling. Only four species gave models that also explained the distribution at the coarser scale. Main conclusions: Although some techniques may apparently deliver good distribution maps for species with scarce and biased data, they need to be taken with caution. When good independent data at a coarser scale are available, cross-scale validation can help to produce more reliable and robust maps. When no independent data are available for validation, however, new data gathering field surveys may be the only option if reliable fine-scale resolution maps are needed. © 2012 Blackwell Publishing Ltd.

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Land use changes, landscape ecology and their socioeconomic driving forces in the Spanish Mediterranean coast (El Maresme County, 1850-2005)

Parcerisas L., Marull J., Pino J., Tello E., Coll F., Basnou C. (2012) Land use changes, landscape ecology and their socioeconomic driving forces in the Spanish Mediterranean coast (El Maresme County, 1850-2005). Environmental Science and Policy. 23: 120-132.
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Doi: 10.1016/j.envsci.2012.08.002

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A set of landscape metrics is used to study the long-term environmental transformation of a typical coastal Mediterranean area from 1850 to 2005. Our figures show a dramatic environmental deterioration between 1950 and 2005. The main proximate drivers of this landscape degradation are the effects of urban sprawl on former agricultural areas located in the coastal plains, together with the abandonment and reforestation of hilly slopes intercepted by low-density residential areas, highways, and other linear infrastructures. Then, a statistical redundancy analysis (RDA) is carried out to identify certain ultimate socioeconomic and political drivers of these environmental impacts. The results confirm, from a quantitative perspective, our main hypothesis that some ultimate geographical endowments and socioeconomic or political drivers have determined land cover changes which, in turn, have altered both structural and functional landscape properties. © 2012 Elsevier Ltd.

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