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

Abstract:

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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Deconstructing the native–exotic richness relationship in plants.

Bartomeus I, Sol D, Pino J, Vicente P, Font X (2011) Deconstructing the native–exotic richness relationship in plants. Global Ecology and Biogeography doi: 10.1111/j.1466-8238.2011.00708.x.

Exploring species attributes and site characteristics to assess plant invasions in Spain

Gassó N., Sol D., Pino J., Dana E.D., Lloret F., Sanz-Elorza M., Sobrino E., Vilà M. (2009) Exploring species attributes and site characteristics to assess plant invasions in Spain. Diversity and Distributions. 15: 50-58.
Link
Doi: 10.1111/j.1472-4642.2008.00501.x

Abstract:

Aim: Biological invasions are a major component of global change with increasing effects on natural ecosystems and human societies. Here, we aim to assess the relationship between plant invader species attributes and the extent of their distribution range size, at the same time that we assess the association between environmental factors and plant invader species richness. Location: Spain, Mediterranean region. Methods: From the species perspective, we calculated the distribution range size of the 106 vascular plant invaders listed in a recently published atlas of alien plant species in Spain. Range size was used as an estimation of the degree of invasion success of the species. To model variation in range size between species as a function of a set of species attributes, we adopted the framework of the generalized linear mixed models because they allow the incorporation of taxonomic categories as nested random factors to control for phylogenetic relationships. From the invaded site perspective, we determined invader plant species richness as the number of species for each 10 × 10 km Universal Transverse Mercator (UTM) grid. For each grid cell, we estimated variables concerning landscape, topography, climate and human settlement. Then, we performed a generalized linear mixed model incorporating a defined spatial correlation structure to assess the relationship between plant invader richness and the environmental predictors. Results: From the species perspective, wind dispersal and minimum residence time appeared to favour invasion success. From the invaded site perspective, we identified high anthropogenic disturbance, low altitude, short distance to the coastline and dry, hot weather as the main correlates to UTM grid cell invader richness. Main conclusions: According to these results, an increasing importance of man-modified ecosystems and global warming in the Mediterranean region should facilitate the expansion of plant invaders, especially wind-dispersed species, leading to the accumulation of invasive species in some sites (i.e. invasion hot spots). © 2008 The Authors.

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Regiones y hábitats más invadidos. A: Vilà M. F. Valladares, A. Traveset, L. Santamaría y P. Castro (eds.). Invasiones Biológicas.

Pino J, Gassó N, Vilà M, Sol D (2008) Regiones y hábitats más invadidos. A: Vilà M. F. Valladares, A. Traveset, L. Santamaría y P. Castro (eds.). Invasiones Biológicas. CSIC-Divulgación. Madrid. Pp. 41-51.

Survey of the naturalised plants and vertebrates in peninsular Spain.

Vilà M, García-Berthou E, Sol D, Pino J (2001) Survey of the naturalised plants and vertebrates in peninsular Spain. Ecologia Mediterranea 27:55-67.