No abstract

In the past, the aquatic pteridophyte Marsilea quadrifolia L. was considered as a weed in paddy fields of southern Europe. The systematic use of herbicides as a crucial component of intensive agronomic approach has led to a dramatic decline in M. quadrifolia populations in European countries, mostly in the Mediterranean area. However, the introduction in recent years of sustainable rice cultivation practices has allowed partial recovery. We present here the results of a research aimed at analyzing the effects of farming typologies in respect to M. quadrifolia growth in the Po Valley area. After having transplanted M. quadrifolia swards in rice fields belonging to different farming systems, we monitored its growth and diffusion. Our results showed that M. quadrifolia has higher vegetative performance in organic farms, even though it can survive in conventional fields with reduced herbicide supply. Differences in water chemistry have limited effects on M. quadrifolia performance, because of its wide ecological amplitude. The shady conditions provided by rice canopy create micro-habitats suitable for M. quadrifolia growth. Cultivating M. quadrifolia in organic rice farms represents an important opportunity for preserving this endangered species in areas of intensive agriculture. This can, meanwhile, represent a valid opportunity to combine nature conservation and productivity offering a new possible income for farmers.

1. Pre-release treatments have long been neglected in plant translocation science, despite being crucial for reintroduction success. Practitioners sometimes adopt acclimation and pre-treatment to reduce environmentally mediated shocks at the recipient site, although the effects of these techniques are unclear. The conditions experienced during cultivation may affect the performance of plants once released.2. The influence of the cultivation environment, and the maternal effects from fertilizer and salt treatments, on post-release performance were investigated on Kosteletzkya pentacarpos, a threatened plant species growing in coastal wetlands.3. Two experimental translocation sites, representing the opposite ends of the ecological range of K. pentacarpos, were chosen: one was a nutrient-rich, freshwater site and the other was a nutrient-poor, brackish water site. Treatment with salt had negligible effects on performance, whereas fertilization positively affected the vegetative and reproductive performance of maternal plants throughout the growing season. Pre-treatment effects were most evident at the highest nutrient site, however, suggesting that pre-treatment could be connected to 'memory' in plants. No maternal effects were observed. 4. Overall, results show that pre-treatment can increase the chances of survival and improve the performance of translocated plants at the recipient site. From an applied conservation perspective, ex situ cultivation and nursing conditions may play a key role in establishing self-sustaining populations during plant translocation. These results have important implications for the use of K. pentacarpos for the restoration of saline wetlands, especially outside of its native range, but also for the conservation of the species via conservation translocation in general.

Alien plants benefit from auto-fertility to spread over areas where the lack of co-evolved mutualists would otherwise limit invasion success. However, the widespread generalists among mutualists and their large geographical ranges allow alien plants to be integrated into networks. The role of residence time also has to be accounted for, as it takes time for a species to spread and adapt to a new area. We investigated how residence time, auto-fertility and pollinator dependence affect reproductive output and invasion success of Asteraceae in Germany. We conducted a multi-species common-garden experiment along an alien–native continuum including 42 species of natives, archaeophytes and neophytes (casual and established), subjecting plant individuals either to free access or exclusion of pollinators. Pollinator dependence does not play a crucial role in invasion success, with most Asteraceae being able to self-fertilize. Surprisingly, both established neophytes and natives showed higher abilities to self-fertilize, while archaeophytes and casual neophytes were more attractive to pollinators. In contrast to casual neophytes, the established neophytes’ strategy was associated with a large reproductive output. Yet, auto-fertility was not associated with range size, since archaeophytes reached the largest range sizes. Elucidating how breeding systems affect invasion success is crucial for predicting and managing invasions.