Tree diversity effects on leaf insect damage on pedunculate oak: The role of landscape context and forest stratum

Castagneyrol, Bastien; Giffard, Brice; Valdés‐Correcher, Elena; Hampe, Arndt

doi:10.1016/j.foreco.2018.11.014

Cited by 34 publications

(55 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We found higher leaf area losses to herbivorous insects in saplings than in mature trees in natural environments, and this pattern was consistent between tropical and boreal forests. These differences between tree age classes are in line with several other studies (reviewed by Barton and Koricheva 2010); they are usually explained by the increase in resource allocation to defence, in particular to an increase in leaf toughness with plant growth (Stiegel et al 2017;Castagneyrol et al 2019). We assessed ontogenetic changes in leaf physical properties by measuring SLA, which not only directly affects leaf palatability for chewing insects, but also positively correlates with other leaf traits (e.g.…”

Section: Bottom-up Effects On Herbivorysupporting

confidence: 78%

Top-down factors contribute to differences in insect herbivory between saplings and mature trees in boreal and tropical forests

2020

View full text Add to dashboard Cite

Ontogenetic changes in herbivory are generally not consistent with ontogenetic changes in defensive traits of woody plants. This inconsistency suggests that other factors may affect ontogenetic trajectories in herbivory. We tested the hypothesis that top-down factors contribute to differences in foliar losses to insects between juvenile and mature trees in tropical and boreal forests. We used artificial caterpillars made of modelling clay to compare predation rates between saplings and mature trees of two common forest species, Siparuna guianensis in Brazil (tropical site) and Betula pubescens in Finland (boreal site). Leaf area losses to chewing insects in saplings were 2.5-fold higher than in mature trees in both species. Physical plant defences (measured as specific leaf area, SLA) did not differ between saplings and mature trees in the boreal forest, whereas in the tropical forest, SLA was greater in saplings than in mature trees. Attack rates on the model prey by birds were higher in the boreal forest, whereas attack rates by arthropod predators were higher in the tropical forest. Overall, predation rates on model prey were consistently higher on mature trees than on saplings at both sites, but in the boreal site, this pattern was primarily driven by birds, whereas in the tropical site, it was primarily driven by arthropod predators. We conclude that the effect of predation on herbivorous insects may considerably contribute to ontogenetic differences in herbivory, but the relative roles of different predatory groups and of top-down and bottom-up factors may vary between environments.

show abstract

Section: Bottom-up Effects On Herbivorysupporting

confidence: 78%

Top-down factors contribute to differences in insect herbivory between saplings and mature trees in boreal and tropical forests

2020

View full text Add to dashboard Cite

show abstract

“…In this sense, a closer mechanistic understanding of ecological factors ranging from life‐history traits (e.g. leaf habit, growth rate) and dominant herbivore species or guilds to abiotic factors—at both micro (e.g light availability at different canopy heights; Castagneyrol, Giffard, Valdés‐Correcher, & Hampe, 2019) to meso‐ and macro‐scale (e.g. climatic variability; Pearse et al, 2009)—and plant endogenous processes (genetic linkages, allocation constraints) under phylogenetically controlled frameworks will pave the road for explaining the presence, absence or variability in plant defensive syndromes and their generative processes.…”

Section: Discussionmentioning

confidence: 99%

Ontogenetic consistency in oak defence syndromes

et al. 2020

View full text Add to dashboard Cite

Plant species allocate resources to multiple defensive traits simultaneously, often leading to so‐called defence syndromes (i.e. suites of traits that are co-expressed across several species). While reports of ontogenetic variation in plant defences are commonplace, no study to date has tested for ontogenetic shifts in defence syndromes, and we know little about the ecological and evolutionary drivers of variation in plant defence syndromes across ontogeny. We tested for ontogenetic variation in plant defence syndromes by measuring a suite of defensive and nutritional traits on saplings and adult trees of 29 oak (Quercus, Fagaceae) species distributed across Europe, North America, and Asia. In addition, we investigated if these syndromes exhibited a phylogenetic signal to elucidate the nature of their macro‐evolutionary variation, whether they were associated with levels of herbivore pressure and climatic conditions, and if any such evolutionary and ecological patterns were contingent on ontogeny. Our analyses revealed three distinct oak defence syndromes: the first included species with high defences, the second species with high defences and low nutrient levels, and the third species with high nutrients and thinner leaves. Interestingly, these defence syndromes remained virtually unchanged across the two ontogenetic stages sampled. In addition, our analyses indicated no evidence for a phylogenetic signal in oak syndromes, a result consistent across ontogenetic stages. Finally, with respect to ecological factors, we found no effect of climatic conditions on defences for either ontogenetic stage, whereas defence syndromes were associated with differing levels of herbivory in adults but not saplings suggesting an association between herbivore pressure and syndrome type that is contingent on ontogeny. Synthesis. Together, these findings indicate that defence syndromes remain remarkably consistent across oak ontogenetic stages, are evolutionarily labile, and while they appear unrelated to climate, they do appear to be associated with herbivory levels in an ontogenetic‐dependent manner. Overall, this study builds towards a better understanding of ecological and evolutionary factors underlying multivariate plant defensive phenotypes.

show abstract

“…The site effects observed in our study suggest that the landscape context might specifically affect insect-tree interactions as demonstrated by contrasting responses of leaf miners to forest diversity in the two study sites. Forest insect herbivory can be thus driven by a complex interplay between local tree diversity and stand isolation in the landscape (Castagneyrol, Giffard, Valdés-Correcher, & Hampe, 2019). Our two studied sites belong to the same biogeographical area, but vary in their forest cover (18.5% vs. 9.2%).…”

Section: Discussionmentioning

confidence: 99%

“…The amount of habitat and distances between habitat patches are known to influence metapopulation processes (Gilpin & Hanski, 1991) and hence the colonization probability of host trees by forest insect herbivores (Robert et al, 2018). Forest insect herbivory can be thus driven by a complex interplay between local tree diversity and stand isolation in the landscape (Castagneyrol, Giffard, Valdés-Correcher, & Hampe, 2019).…”

Section: Discussionmentioning

confidence: 99%

Tree diversity drives associational resistance to herbivory at both forest edge and interior

Guyot

Jactel

Imbaud

et al. 2019

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

Tree diversity is increasingly acknowledged as an important driver of insect herbivory. However, there is still a debate about the direction of associational effects that can range from associational resistance (i.e., less damage in mixed stands than in monocultures) to the opposite, associational susceptibility. Discrepancies among published studies may be due to the overlooked effect of spatially dependent processes such as tree location within forests. We addressed this issue by measuring crown defoliation and leaf damage made by different guilds of insect herbivores on oaks growing among conspecific versus heterospecific neighbors at forest edges versus interior, in two closed sites in SW France forests. Overall, oaks were significantly less defoliated among heterospecific neighbors (i.e., associational resistance), at both forest edge and interior. At the leaf level, guild diversity and leaf miner herbivory significantly increased with tree diversity regardless of oak location within stands. Other guilds showed no clear response to tree diversity or oak location. We showed that herbivore response to tree diversity varied among insect feeding guilds but not between forest edges and interior, with inconsistent patterns between sites. Importantly, we show that oaks were more defoliated in pure oak plots than in mixed plots at both edge and forest interior and that, on average, defoliation decreased with increasing tree diversity from one to seven species. We conclude that edge conditions could be interacting with tree diversity to regulate insect defoliation, but future investigations are needed to integrate them into the management of temperate forests, notably by better understanding the role of the landscape context.

show abstract

Tree diversity effects on leaf insect damage on pedunculate oak: The role of landscape context and forest stratum

Cited by 34 publications

References 60 publications

Top-down factors contribute to differences in insect herbivory between saplings and mature trees in boreal and tropical forests

Top-down factors contribute to differences in insect herbivory between saplings and mature trees in boreal and tropical forests

Ontogenetic consistency in oak defence syndromes

Tree diversity drives associational resistance to herbivory at both forest edge and interior

Contact Info

Product

Resources

About