Invasion of Rubus praecox (Rosaceae) is promoted by the native tree Aristotelia chilensis (Elaeocarpaceae) due to seed dispersal facilitation

Abstract

Seed dispersal facilitation among plant neighbours can be defined as an increase in the number, distances, and/or places reached by a plant's seeds that is due to the presence of co-fruiting plant neighbours with which it shares seed dispersers. Many cases of this phenomenon have been described among native species and some also among introduced invasive species. Moreover, facilitation of native species recruitment by non-native fleshy-fruiting trees has been reported. Surprisingly, seed dispersal facilitation of exotic species by native species is either less common or has not been properly documented so far. Casual observation of secondary vegetation in La Araucanía Region, Chile, suggests that more individuals of exotic fleshy-fruiting bird-dispersed Rubus praecox (Rosaceae) are established under the native fleshy fruiting bird-dispersed subdioecious tree Aristotelia chilensis (Elaeocarpaceae) than under other native dry-fruiting tree species in the same areas. To assess whether these observation-suggested differences are statistically significant, two plots were sampled for interspecific associations between Rubus and Aristotelia and between Rubus and the most common dry-fruiting monoecious tree -Lomatia hirsuta (Proteaceae). The first important conclusion from this study is that invasive Rubus is substantially more common under both focal tree species than in open grasslands. Second, Rubus is associated more strongly with fleshy-fruiting Aristotelia than with dry-fruiting Lomatia in this landscape. Additionally, the frequency of Rubus is higher under Aristotelia fruiting (female or hermaphroditic) trees. Management implications are discussed.Keywords: Frugivory, plant invasion, seed dispersal, South-Central Chile. RESUMENLa facilitación de la dispersión de las semillas entre plantas vecinas se puede definir como un incremento en el número, distancia, y/o lugares alcanzados por las semillas de una planta debido a la presencia de plantas vecinas que co-fructifican y con las que la especie comparte dispersores de semillas. Se han descrito muchos casos de este fenómeno entre especies nativas y algunas también entre especies introducidas invasoras. Además, se ha informado de la facilitación del reclutamiento de especies nativas por árboles no-nativos de fruto carnoso. Sorprendentemente, la facilitación de la dispersión de semillas de las especies exóticas por especies nativas es menos común, o no ha sido debidamente documentada hasta el momento. La observación casual de la vegetación secundaria en la Región de la Araucanía, Chile, sugiere que más individuos de la especie exótica Rubus praecox (Rosaceae), cuyos frutos carnosos son dispersados por las aves, se establecen bajo el árbol nativo Aristotelia chilensis (Elaeocarpaceae) que también posee frutos carnosos, que bajo otra especies de árboles nativos con frutos secos en las mismas áreas. Para evaluar si las diferencias de observación sugeridas son estadísticamente significativas, se muestrearon dos parcelas para estudiar las asociaciones interespecífi...

Invasive Blackberry Species in Oregon: Their Identity and Susceptibility to Rust Disease and the Implications for Biological Control

“…It involved surface sterilization of cuttings (15% bleach for 5 min), removal from containment, and transfer to a conventional greenhouse for rooting and propagation. In addition to field samples from Oregon, one accession of R. praecox (Oehrens and Gonzalez 1974;Rejmánek 2015) was supplied by L. Ciampi (Univ. Austral de Chile, Valdivia), and two accessions each of R. praecox and R. armeniacus were supplied from the Czech Republic by M. Sochor and B. Trávníček. Rooted specimens for the production of test canes were transplanted into 15-cm clay pots filled with a standard artificial soil mix of peat (41%), bark (11%), perlite (23%), vermiculite (23%), sand (2%), and Micromax ® trace minerals (Scotts Miracle-Gro, Marysville, OH 43040).…”

“…European blackberry is invasive in Chile, Australia, and the United States. For this reason, biological control using Phragmidium violaceum (Schultz) G. Winter, the cause of a rust disease, was pursued both in Chile (Oehrens and Gonzalez 1974;Rejmánek 2015) and in Australia. Two strains were introduced originally into Australia, one illegally in 1984 and a second after a complete risk assessment (Mahr and Bruzzese 1998).…”

Is evolution of apomicts driven by the phylogeography of the sexual ancestor? Insights from European and Caucasian brambles (Rubus, Rosaceae)

“…Effective long‐distance seed dispersal by large birds is well documented for many wetland plants (van Leeuwen, van der Velde, van Groenendael, & Klaassen, ) but remains enigmatic for other plant groups, as its effectiveness can be influenced by many factors (Nathan et al., ; Schupp, Jordano, & Gómez, ). Brambles are typical bird‐dispersed plants with a wide spectrum of dispersers (Jordano, ; Rejmánek, ). Spanish populations of R. ulmifolius were found to be dispersed mainly by various migrant birds (Jordano, ), which may lead to the assumption of intensive gene flow and weak geographical genetic structure.…”

Evaluation of rust pathogenicity (Phragmidium violaceum) as a biological control agent for the invasive plant Rubus ulmifolius on Robinson Crusoe Island, Chile

“…R. ulmifolius is found in most agricultural and forest landscapes of southern-central Chile (33°-43°S, Matthei et al 1995), probably confused in some areas with R. praecox, recently described in Chile by Rejmánek (2015). By the first half of the 1970s about 5% of the agricultural land area in mainland Chile was infested by R. ulmifolius, R. cf.…”