Simplification of agricultural environments is linked to declines in biodiversity. Improving the floral diversity within and around these areas may result in more robust and diverse ecosystems. We investigated how floral resource abundance, diversity, and species composition in a cranberry agricultural system correlated to the abundance and overall invertebrate diversity and to the abundance and diversity of specific invertebrate groups of agricultural importance (e.g. parasitoids, phytophagous taxa, pollinators and predators). This study focused on habitats immediately surrounding cranberry production and included grassy dikes under a managed system ('dike'), and semi-natural areas growing on the surrounding support land ('semi-natural'). Floral resource availability and diversity tended to be similar between habitats, while invertebrate richness, diversity and composition differed. As the availability of floral resources increased, invertebrate abundance increased but diversity decreased. Overall invertebrate community composition differed with the specific species and availability of floral resources. The habitat type and floral resource composition impacted some agriculturally important groups, as pollinator abundance was higher in the semi-natural habitat, and parasitoid abundance varied with floral resource composition across both habitats. These results suggest that managing the structural and floral resource diversity associated with agroecosystems can help support local biodiversity. However, these systems may disproportionately benefit more common taxonomic groups. The difference in responses of individual taxonomic groups also highlights the potential tradeoffs of focusing on only a subset of biodiversity aspects. Floral resources were similar between dike and semi-natural areas while invertebrate richness, diversity, and composition differed. Invertebrate community composition differed based on presence of specific flora. Pollinator abundance was twice as high in the semi-natural habitat. image

Patterns of woody-plant mortality have been linked to global-scale environmental changes, such as extreme drought, heat stress, more frequent and intense fires, and episodic outbreaks of insects and pathogens. Although many studies have focussed on survival and mortality in response to specific physiological stresses, little attention has been paid to the role of genetic heritability of traits and local adaptation in influencing patterns of plant mortality, especially in non-native species. Tamarix spp. is a dominant, non-native riparian tree in western North America that is experiencing dieback in some areas of its range due to episodic herbivory by the recently introduced northern tamarisk leaf beetle (Diorhabda carinulata). We propose that genotype × environment interactions largely underpin current and future patterns of Tamarix mortality. We anticipate that (i) despite its recent introduction, and the potential for significant gene flow, Tamarix in western North America is generally adapted to local environmental conditions across its current range in part due to hybridization of two species; (ii) local adaptation to specific climate, soil and resource availability will yield predictable responses to episodic herbivory; and (iii) the ability to cope with a combination of episodic herbivory and increased aridity associated with climate change will be largely based on functional tradeoffs in resource allocation. This review focusses on the potential heritability of plant carbon allocation patterns in Tamarix, focussing on the relative contribution of acquired carbon to non-structural carbohydrate (NSC) pools versus other sinks as the basis for surviving episodic disturbance. Where high aridity and/or poor edaphic position lead to chronic stress, NSC pools may fall below a minimum threshold because of an imbalance between the supply of carbon and its demand by various sinks. Identifying patterns of local adaptation of traits related to resource allocation will improve forecasting of Tamarix population susceptibility to episodic herbivory.

1. The Chinese brake fern (Pteris vittata L.; Pteridaceae) can accumulate up to 27 000 mg kg−1 dry wt. of arsenic (As) from the soil into its above‐ground biomass. They may use this As to deter invertebrate threats.2. This study explored how As concentrations [As] in the fern, and in soil associated with the fern, influenced the abundance and composition of various invertebrates.3. Populations of P. vittata were identified in the field. Soils from the base of the fern and from 3 m away of each plant were collected and pitfall traps were installed. Soil and fern arsenic concentrations ([As]) were measured via inductively coupled plasma mass spectrometry and invertebrates were identified to order and classified by feeding guild.4. Increased [As] did not affect all feeding guilds and orders equally. For example, individual herbivore abundance did not decrease as [As] increased, but predator abundance did. In many cases, the impact of soil [As] on invertebrates depended on the distance from the fern. Fern [As] also influenced components of the community, but only at 3 m away from the fern. Furthermore, the abundances of many invertebrate groups were higher beneath the fern, where [As] was higher.5. These results suggest that hyperaccumulated As can impact the invertebrate community, but the defensive benefits of hyperaccumulation are more complex than have been previously described. The authors advocate that future studies examining the potential defensive benefits of hyperaccumulation should do so in a natural setting that incorporates this complexity and invertebrate richness.