Analysis of an invasion in the community context: a case study about differences and similarities between native and non-native shrubs

Abstract

Although much effort has been devoted to identify plant traits related to invasiveness, the success of this approach remains elusive, likely because the relevance of particular traits for invasions is context-dependent. We studied plant invasions in the context of the recipient community in a mountain ecosystem of western Argentina by comparing traits between two non-native shrubs, Rosa canina and R. rubiginosa, and all native shrubs coexisting with them. We expected that both rose species differed from natives in traits related to an acquisitive strategy of resources. We grouped native shrubs into species with high (abundant) and low abundance (rare). We expected smaller differences between non-natives and abundant natives than between non-natives and rare natives, as shrub abundance may depend on possessing a particular suite of traits, independent of species origin. We found that both rose species were different from native shrubs when analyzing all traits in combination. Non-natives presented a strategy that may allow them to acquire resources and grow at faster rates than natives, offering support to our prediction. Yet, native and non-native shrub species overlapped in flower phenology. When comparing non-natives to abundant and rare natives, we found no support for our expectation, as non-natives did not show smaller differences with abundant natives, but shared similarities with rare natives. This pattern suggests successful coexistence via niche partitioning, but this possibility deserves future studies. Our work highlights the importance of considering non-native plant traits in a community context to further understand the invasion process.