Seed provenance for changing climates: early growth traits of nonlocal seed are better adapted to future climatic scenarios, but not to current field conditions

Germination and Seedling Growth of Water Primroses: A Cross Experiment between Two Invaded Ranges with Contrasting Climates

Aquatic ecosystems are vulnerable to biological invasions, and will also be strongly impacted by climate change, including temperature increase. Understanding the colonization dynamics of aquatic invasive plant species is of high importance for preservation of native biodiversity. Many aquatic invasive plants rely on clonal reproduction to spread, but mixed reproductive modes are common. Under future climate changes, these species may favor a sexual reproductive mode. The aim of this study was to test the germination capacity and the seedling growth of two water primrose species, Ludwigia hexapetala and Ludwigia peploides, both invasive in Europe and in the United States. We performed a reciprocal transplant of seeds of L. hexapetala and L. peploides from two invasive ranges into experimental gardens characterized by Oceanic and Mediterranean-type climates. Our results showed that higher temperatures increased or maintained germination percentages and velocity, decreased survivorship of germinants, but increased their production of biomass. The origin of the seeds had low impact on L. hexapetala responses to temperature, but greatly influenced those of L. peploides. The invasiveness of water primroses in ranges with Oceanic climates might increase with temperature. The recruitment from seed banks by these species should be considered by managers to improve the conservation of native aquatic and wetland plant species.

Improving vegetation quality for the restoration of pollinators – the relevance of co-flowering species in space and time

Pollination is a key ecosystem function that directly and indirectly provides food for all organisms – regardless of the trophic level. In degraded ecosystems, installing plant and habitat resources for pollinators starts with an understanding of the temporal and spatial habitat needs of pollinators, and the augmentations, the co-factors and conditions required for pollinator populations. These co-factors, not immediately recognised as linked to the provision of pollination services, are critical for complexity and include a diverse array of resources such as food plants for larvae, shelter and temporal legacies of earlier flowering species. Practical steps for restoration include the installation of an array of plant species that provide a staggered supply of flowers and this can be refined to include specific floral types that are the mega supermarkets for nectar and pollen resources in them.