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.
Enllaç
Doi: 10.1111/j.1654-1103.2011.01363.x

Resum:

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.

Llegeix més

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.
Enllaç
Doi: 10.1111/j.1466-8238.2011.00708.x

Resum:

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.

Llegeix més

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.
Enllaç
Doi: 10.1111/j.1466-8238.2010.00573.x

Resum:

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.

Llegeix més

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.
Enllaç
Doi: 10.1111/j.1654-109X.2011.01159.x

Resum:

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.

Llegeix més

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.
Enllaç
Doi: 10.1111/j.1472-4642.2012.00911.x

Resum:

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.

Llegeix més

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.
Enllaç
Doi: 10.1016/j.envsci.2012.08.002

Resum:

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.

Llegeix més

Ecological networks: Are they enough for connectivity conservation? A case study in the Barcelona Metropolitan Region (NE Spain)

Pino J., Marull J. (2012) Ecological networks: Are they enough for connectivity conservation? A case study in the Barcelona Metropolitan Region (NE Spain). Land Use Policy. 29: 684-690.
Enllaç
Doi: 10.1016/j.landusepol.2011.11.004

Resum:

This paper extends the debate on corridor effectiveness at regional planning scale, by exploring the contribution to landscape connectivity of a proposed ecological network and the remaining non-urbanized matrix in the Barcelona Metropolitan Region (BMR). Using the Ecological Connectivity Index, we evaluated the expected connectivity loss after the development of the approved urban plans in the region. Thus, we compared the baseline (present-day) and the projected (after planned urban development) connectivity scenarios for total, forest and agricultural habitats. Then, we estimated the mitigation in connectivity loss when successively removing from plans those development sectors included in protected sites, first order corridors, and second-order corridors of the ecological network, and in the rest of land matrix. Estimations were done for all the BMR and for inside versus outside the set of sites currently protected.The ecological network and the rest of matrix contributed equally to mitigating the expected connectivity loss, but while the former was more effective for forest habitats, the latter was especially constructive for croplands. This was due to a heterogeneous distribution of habitats, protected reserves and urban development areas. Still, connectivity preservation within protected sites appeared to be highly dependent on what is going on outside the ecological network, as we observed in particular for agricultural habitats. This result extends at regional scale the statement that no park is an island, but is highly affected by the land use and land cover dynamics of its surroundings. © 2011.

Llegeix més

Direct and indirect landscape effects on Quercus ilex regeneration in heterogeneous environments

Puerta-Piñero C., Pino J., Gómez J.M. (2012) Direct and indirect landscape effects on Quercus ilex regeneration in heterogeneous environments. Oecologia. 170: 1009-1020.
Enllaç
Doi: 10.1007/s00442-012-2373-1

Resum:

Understanding how plant-animal interactions shape plant regeneration is traditionally examined at local scales. In contrast, landscape ecologists working at regional scales often have to infer the mechanisms underlying vegetation patterns. In this study, we empirically explored how landscape attributes (patch connectivity, size, shape, irradiance, slope, and elevation) influence biotic interactions in 1- and 2-year seedlings and saplings of Quercus ilex. We combined field data and GIS-based information under a set of five connectivity scenarios, presuming low, intermediate, and long-distance seed dispersal. Our study emphasizes that landscape, apart from its direct effects on plants, plays a key, albeit indirect, role in plant demography through its effects on seed dispersers and predators. Moreover, the effects of landscape on recruitment differed between plant life stages. One-year seedlings and saplings appear to depend more on plant-animal interactions, while 2-year seedlings depend more on irradiance. Differences in patch connectivity resulted in direct and indirect effects on biotic interactions, which, in turn, produced contrasting positive and negative effects on regeneration at different stages of the life cycle. While jays and wild boars seem crucial to all life stages and most of the connectivity scenarios, rodents and herbivores affected only 1-year seedlings and saplings, respectively, and only a few of the connectivity scenarios. By simultaneously including an ensemble of explanatory factors, our study emphasizes that regeneration depends on a set of key drivers, both abiotic (i. e. irradiance) and biotic (i. e. jays and wild boars), whose effects are greatly modulated by landscape traits. © 2012 Springer-Verlag.

Llegeix més

Does participatory mapping increase conflicts? A randomized evaluation in the Bolivian Amazon

Reyes-García V., Orta-Martínez M., Gueze M., Luz A.C., Paneque-Gálvez J., Macía M.J., Pino J. (2012) Does participatory mapping increase conflicts? A randomized evaluation in the Bolivian Amazon. Applied Geography. 34: 650-658.
Enllaç
Doi: 10.1016/j.apgeog.2012.04.007

Resum:

Participatory mapping of indigenous lands and resources is increasingly seen as a precondition for securing legal recognition of indigenous land rights. But because participatory mapping might have unintended impacts on the functioning of rural communities, researchers have put a great effort in analyzing the effects of participatory mapping. In this article, we used a randomized evaluation to assess the effects of participatory mapping in conflicts with external actors and with neighbouring villages in the Tsimane' indigenous territory, Bolivian Amazon. We randomly assigned villages to a treatment and a control group, conducted participatory mapping with villages in the treatment group, and evaluated the effects of mapping village resources on the number of reported conflicts with and attitudes towards a) external actors and b) indigenous peoples from other villages. The exercise allows us to assess the effect of participatory mapping on conflicts while controlling for the political context. Results from our study indicate that conducting participatory mapping in randomly selected villages did not produce any effect of real or statistical significance on either 1) the number of conflicts with outsiders entering Tsimane' villages, 2) the number of conflicts with Tsimane' from other villages, 3) negative attitudes or opinions of outsiders, or 4) negative attitudes or opinion of Tsimane' from other villages. Our results suggest that some of the effects that have been attributed to participatory mapping are not the inevitable outcome of mapping . per se; rather, they probably stem from other previous or ongoing processes that determine whether communities engage in mapping their lands and how they do so. © 2012 Elsevier Ltd.

Llegeix més

Ecological niche and species traits: Key drivers of regional plant invader assemblages

Thuiller W., Gassó N., Pino J., Vilà M. (2012) Ecological niche and species traits: Key drivers of regional plant invader assemblages. Biological Invasions. 14: 1963-1980.
Enllaç
Doi: 10.1007/s10530-012-0206-0

Resum:

Linking species traits to niche properties is fundamental to understand the spatial structure of invasive species assemblages and the invasion process itself. Using information on 74 invasive species in Spain, the aims of this paper are to (1) test whether invasive plant species assemblages follow a nested pattern at the regional scale, (2) inspect the relationship between range size and niche properties (position and breadth) of invasive species to test whether the nested pattern is a product of species niche overlap; and finally (3) examine how species traits of invaders are related to their niche properties. We show that regional invasive plant species assemblages in Spain are organized in nested subsets. Invasive species with restricted range occur in areas invaded by widespread invaders. By relating nestedness metrics to species' niche properties from multivariate analyses, we found that these restricted invaders are less tolerant of broad climatic and landscape conditions than widespread invaders. Finally, regarding the association between niche properties and species traits, we found that species with large environmental niche breadth commonly exhibit non N-fixing strategy, short-life span, and clonal growth, while those with niche position in anthropogenic coastal areas were perennial and clonal species of unintentional and agricultural origin. Using an integrative approach linking the regional spatial structure of invasive plant assemblages, species niche properties and species traits, we were able to understand the potential causes of invasive species distribution in Spain. The approach developed in this research could be easily applied to other areas to disentangle the mechanisms driving invasive species distributions. © 2012 Springer Science+Business Media B.V.

Llegeix més