Comparison of the vascular exotic flora in continental islands: Sardinia (Italy) and Balearic Islands (Spain)

[EN] This paper provides a comparison of the vascular exotic flora of Sardinia and that of the Balearic Islands, both territories belonging to the Western Mediterranean biogeographic subregion. The study has recorded 531 exotic taxa in Sardinia (18.8% of the total flora) while 360(19%) in the Balearic Islands; 10 are new to Sardinia (3 of which for Italy) and 29 to the Balearic Islands. The alien flora of Sardinia is included in 99 families; Fabaceae is the richest (49 taxa), followed by Poaceae (33) and Asteraceae (31) while in the Balearic Islands in 90 families, with a predominance of Fabaceae (32), Asteraceae (31) and Poaceae (27). The comparison of the biological spectra reveals that in Sardinia phanerophytes are the most represented in Sardinia and therophytes in the Balearic Islands. A detailed analysis shows that most of the exotic taxa (246) are shared by both territories with a clear dominance of neophytes rather than archaeophytes. A study of the geographical origin shows supremacy of the American element over the Mediterranean. The majority of introduced exotic taxa are a result of intentional human introductions (76% SA, 77% BL), mainly for ornamental use (43% SA, 45% BL). The most occupied habitats are the semi-natural, agricultural and synanthropic for both territories, but attending to invasive plants, coastal habitats in Sardinia and wetlands in the Balearic Islands are the most sensitive. A part of the work deals with the causes of fragility and low resilience of the different habitats.[ES] Se presenta un estudio comparativo de la flora vascular exótica de Cerdeña y de las Baleares, dos sistemas insulares pertenecientes a la subregión biogeográfica Mediterránea Occidental. En Cerdeña se han contabilizado 531 táxones exóticos (18,8% del total de su flora), mientras que en las Baleares 360 (19%), siendo 10 citas nuevas para Cerdeña (3 de las cuales para Italia) y 29 para Baleares. La flora exótica de Cerdeña está incluida en 99 familias, y Fabaceae es la más rica (49 táxones), seguida por Poaceae (33) y Asteraceae (31), frente a 90 familias para las Baleares, con predominio de Fabaceae (32), Asteraceae (31) y Poaceae (27). Se han encontrado diferencias respecto a los tipos biológicos, con un predominio de los fanerófitos en Cerdeña y de los terófitos en las Baleares. Un análisis detallado muestra que buena parte de estos táxones (246) son compartidos por ambos territorios, así como una dominancia de los neófitos frente a los arqueófitos. Respecto al origen geográfico, ambos territorios presentan una preeminencia del elemento americano sobre el mediterráneo. En referencia a las vías de introducción, la mayor parte de los táxones ha sido introducida por parte del hombre de forma intencionada (76% SA, 77% BL) en particular para uso ornamental (43% SA, 45% BL). 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Native and exotic invasive plants have fundamentally similar carbon capture strategies

1. Leaf trait relationships of native and exotic invasive species from a range of habitats were compared to assess consistency across habitats and the role of disturbance. 2. One hundred and twenty-two native and exotic species were sampled in five habitats in eastern Australia. Specific leaf area, foliar nitrogen (Nmass), assimilation rate (Amass) and dark respiration (Rmass) were measured for each species. Plants were classified into four types: native undisturbed, native disturbed, exotic invasive undisturbed and exotic invasive disturbed. 3. All traits were positively correlated and slopes were homogeneous within habitats. Significant differences between plant types in slope elevation were found in only two of 18 cases. There were significant shifts in group means along a common slope between plant types within habitats. These shifts were associated with disturbed vs. undisturbed areas, with plant types from disturbed areas having higher trait values. 4. Synthesis. Exotic invasive and native species do not have fundamentally different carbon capture strategies. The carbon capture strategy of a species is strongly associated with disturbance, with species from disturbed sites having traits that confer capacity for fast growth. Thus, differences between exotic invasives and natives may reflect differences in the environmental conditions of the sites where they occur rather than differences between exotic invasives and natives per se