Precipitation seasonality promotes acquisitive and variable leaf water-economics traits in southwest Australian granite outcrop species

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blaa053 ◽

2020 ◽

Author(s):

Gianluigi Ottaviani ◽

Matteo Marcantonio

Keyword(s):

Plant Species ◽

Water Use ◽

Plant Traits ◽

Leaf Traits ◽

Plant Species Richness ◽

Precipitation Regime ◽

Water Economics ◽

Functional Studies ◽

Precipitation Seasonality ◽

Granite Outcrop

Abstract Southwestern Australia (SWA) is a global biodiversity hotspot characterized by a mediterranean climate and is among the world’s oldest and resource-poorest landscapes. Within this region, granite outcrops provide habitat complexity, and contribute to high levels of species diversity and endemism. Granite outcrop plant species are characterized by distinct anatomical, morphological and eco-physiological traits. So far, functional studies of SWA granite outcrop plants examined trait patterns along the stark aridity gradient that occurs in the region. Despite precipitation seasonality being an important climatic driver of plant species richness and distribution in mediterranean-type ecosystems, relationships between plant traits and precipitation seasonality remain understudied. Here, we investigated granite outcrop species’ responses to changes in precipitation seasonality in terms of average and variability values of leaf traits related to water use efficiency. We found that plants displayed more acquisitive and variable trait values with increasing precipitation seasonality. These patterns are likely associated with the long-term effect of the stable and predictable precipitation regime in the old SWA that may have fine-tuned plant water use strategies to maximize water acquisition during the most favourable season.

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Data on Herbivore Performance and Plant Herbivore Damage Identify the Same Plant Traits as the Key Drivers of Plant–Herbivore Interaction

Insects ◽

10.3390/insects11120865 ◽

2020 ◽

Vol 11 (12) ◽

pp. 865

Author(s):

Zuzana Münzbergová ◽

Jiří Skuhrovec

Keyword(s):

Plant Species ◽

Plant Traits ◽

Leaf Traits ◽

Leaf Damage ◽

Herbivore Damage ◽

Herbivore Performance ◽

Physical Defense ◽

Wide Range ◽

Herbivore Interactions ◽

Plant Herbivore

Data on plant herbivore damage as well as on herbivore performance have been previously used to identify key plant traits driving plant–herbivore interactions. The extent to which the two approaches lead to similar conclusions remains to be explored. We determined the effect of a free-living leaf-chewing generalist caterpillar, Spodoptera littoralis (Lepidoptera: Noctuidae), on leaf damage of 24 closely related plant species from the Carduoideae subfamily and the effect of these plant species on caterpillar growth. We used a wide range of physical defense leaf traits and leaf nutrient contents as the plant traits. Herbivore performance and leaf damage were affected by similar plant traits. Traits related to higher caterpillar mortality (higher leaf dissection, number, length and toughness of spines and lower trichome density) also led to higher leaf damage. This fits with the fact that each caterpillar was feeding on a single plant and, thus, had to consume more biomass of the less suitable plants to obtain the same amount of nutrients. The key plant traits driving plant–herbivore interactions identified based on data on herbivore performance largely corresponded to the traits identified as important based on data on leaf damage. This suggests that both types of data may be used to identify the key plant traits determining plant–herbivore interactions. It is, however, important to carefully distinguish whether the data on leaf damage were obtained in the field or in a controlled feeding experiment, as the patterns expected in the two environments may go in opposite directions.

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