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Endozoochory of similar plants by storks and gulls

Research into the dispersal of plants lacking a fleshy fruit by avian endozoochory remains limited, particularly regarding the different roles of specific vectors in the same habitat. Plants dispersed by endozoochory were compared between two migratory waterbirds differing in body size: the lesser black-backed gull, and the white stork. Faeces and pellets were collected from roosting flocks on dykes in the Doñana rice fields, and extracted intact seeds. 424 intact seeds from 21 plant taxa were recovered, 11 of which germinated under laboratory conditions. Eight plant species are considered weeds, four of them as alien species, and only two have a fleshy fruit. Toadrush (Juncus bufonius) was the dominant species, accounting for 49% of seeds recovered. Community analyses revealed no differences in the proportions of each plant species dispersed by the two birds, suggesting that waterbird plant dispersal networks are different from frugivore networks. These avian vectors provide maximum dispersal distances several orders of magnitude greater than predicted from their dispersal syndromes. Endozoochory by migratory waterbirds has major implications for plant distributions in a rapidly changing world. informacion[at] Martín-Vélez et al (2020) Endozoochory of the same community of plants lacking fleshy fruits by storks and gulls. J Veg Science DOI 10.1111/jvs.12967
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A novel system for ranking and comparing the impacts of introduced species

A novel system for ranking and comparing the impacts of introduced species

Many alien taxa are known to cause socio-economic impacts by affecting the different constituents of human well-being (security; material and immaterial assets; health; social, spiritual and cultural relations; freedom of choice and action). Attempts to quantify socio-economic impacts in monetary terms are unlikely to provide a useful basis for evaluating and comparing impacts of alien taxa because they are notoriously difficult to measure and important aspects of human well-being are excluded or ignored. A novel standardised method for classifying alien taxa in terms of the magnitude of their impacts on human well-being is proposed, based on the capability approach from welfare economics. The core characteristic of this approach is that it uses changes in people's activities as a common metric for evaluating impacts on well-being. Impacts are assigned to one of five levels, from Minimal Concern to Massive, according to semi-quantitative scenarios that describe the severity of the impacts. Taxa are then classified according to the highest level of deleterious impact that they have been recorded to cause on any constituent of human well-being. The scheme also includes categories for taxa that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. To demonstrate the utility of the system, impacts of amphibians were globally classified. These showed a variety of impacts on human wellbeing, with the cane toad (Rhinella marina) scoring Major impacts. For most species, however, no studies reporting impacts on human well-being were found, i.e. these species were Data Deficient. The classification provides a consistent procedure for translating the broad range of measures and types of impact into ranked levels of socioeconomic impact, assigns alien taxa on the basis of the best available evidence of their documented deleterious impacts, and is applicable across taxa and at a range of spatial scales. The system was designed to align closely with the Environmental Impact Classification for Alien Taxa (EICAT) and the Red List, both of which have been adopted by the International Union of Nature Conservation (IUCN), and could therefore be readily integrated into international practices. Methods in Ecology and Evolution Doi 10.1111/2041-210X.12844