Consistent increase in herbivory along two experimental plant diversity gradients over multiple years

Global declines in biodiversity have raised concerns over the implications of diversity loss for the functioning of ecosystems. Plant diversity loss has impacts throughout food webs affecting both consumer communities and ecosystem functions mediated by consumers. Effects of plant diversity loss on communities of invertebrate predators have been documented, yet little is known about how these translate into variations in predation rates. We measured predation rates along two plant diversity gradients in grassland experiments manipulating species richness and functional diversity. Measurements were conducted at two different heights (ground and vegetation) and in two different seasons (spring and summer), using three different types of baits. Our results show that overall predation rates increase with plant species richness, but effects are seasonally variable and are much more pronounced on the ground than in the vegetation. Plant functional diversity did not consistently affect predation rates in our experiments. Potential mechanistic explanations for an effect of plant diversity on predation include higher complementarity between predator species or reduced intraguild predation with increasing structural complexity at higher plant diversity. These results underline the importance of high local plant diversity for natural pest control.

show abstract

“…, Meyer et al. ). This increase in herbivory occurred despite the increased predation pressure documented here.…”

Section: Discussionmentioning

confidence: 99%

“…Yet, there is growing evidence for higher consumer‐related functioning with higher plant diversity for herbivory (Meyer et al. ) and pollination (Ebeling et al. ).…”

Section: Introductionmentioning

confidence: 99%

Plant diversity increases predation by ground‐dwelling invertebrate predators

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Second, the leaf biomass of each species in each mixture was multiplied by the respective herbivory rate to obtain the leaf biomass consumed from this species in gram dry weight per square meter. Third, the total biomass removed from a particular plant community was calculated by summing the consumed leaf biomass over all plant species in the community 44, 45 .…”

Section: Supplementary Materialsmentioning

confidence: 99%

“…Herbivory was measured during the biomass harvest twice a year – typically at the end of May and the end of August. Herbivory was measured in five years (2012 to 2014) 44, 45 . For each target species present in the sorted biomass samples, usually, 30 fully developed leaves (only 20 in 2012 and 2013) were sampled randomly for herbivory measurements.…”

Section: Supplementary Materialsmentioning

confidence: 99%

Plant traits are poor predictors of long-term ecosystem functioning

Plas

Schröder-Georgi

Weigelt

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

4 6 * These authors contributed equally 4 7 4 8 ABSTRACT 4 9Earth is home to over 350,000 vascular plant species 1 that differ in their traits in 5 0 innumerable ways. Yet, a handful of functional traits can help explaining major differences 5 1 among species in photosynthetic rate, growth rate, reproductive output and other aspects of plant 5 2 performance 2-6 . A key challenge, coined "the Holy Grail" in ecology, is to upscale this 5 3 understanding in order to predict how natural or anthropogenically driven changes in the identity 5 4 and diversity of co-occurring plant species drive the functioning of ecosystems 7,8 . Here, we 5 5 analyze the extent to which 42 different ecosystem functions can be predicted by 41 plant traits 5 6 in 78 experimentally manipulated grassland plots over 10 years. Despite the unprecedented 5 7 number of traits analyzed, the average percentage of variation in ecosystem functioning that they 5 8 jointly explained was only moderate (32.6%) within individual years, and even much lower 5 9 (12.7%) across years. Most other studies linking ecosystem functioning to plant traits analyzed 6 0 no more than six traits, and when including either only six random or the six most frequently 6 1 studied traits in our analysis, the average percentage of explained variation in across-year 6 2 ecosystem functioning dropped to 4.8%. Furthermore, different ecosystem functions were driven 6 3 by different traits, with on average only 12.2% overlap in significant predictors. Thus, we did not 6 4 find evidence for the existence of a small set of key traits able to explain variation in multiple 6 5 ecosystem functions across years. Our results therefore suggest that there are strong limits in the 6 6 extent to which we can predict the long-term functional consequences of the ongoing, rapid 6 7 changes in the composition and diversity of plant communities that humanity is currently facing. 6 8 6 9 BODY 7 0 Worldwide, ecological communities are rapidly changing due to various anthropogenic 7 1 activities 9-12 . This biodiversity change is non-random, and the functional traits of organisms 7 2 driving their growth, survival and reproduction are key in determining which species thrive and 7 3 which perish under global change 13-15 . This may have important implications, as traits not only 7 4 affect individual plant performance, but they may also drive various ecosystem functions such as 7 5biomass production, and the services these functions provide to human well-being 7,8,15 . 6Predicting rates of ecosystem functioning, such as biomass production or carbon 7 7 sequestration, from the composition or diversity of traits in plant communities has been coined 7 8 the "Holy Grail" in ecology 7,8 . Various studies have shown links between plant traits and 7 9 species-level variation in photosynthetic rate, growth, and reproductive output present in the 8 0 plant kingdom 3-5 . However, in natural communities, plants occur in various abiotic 8 1 environments, and they interact with individuals from other species, so ...

show abstract

“…Current knowledge about mechanisms driving associational effects in plants is largely derived from controlled experiments and has been more commonly addressed in grasslands than in forests. (Grossman et al, 2018;Meyer et al, 2017). Although such experiments perfectly control for plant richness and composition, they are designed to minimize other sources of variation in plantherbivore interactions like spatial variability.…”

mentioning

confidence: 99%

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

Guyot

Jactel

Imbaud

et al. 2019

Ecology and Evolution

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

Consistent increase in herbivory along two experimental plant diversity gradients over multiple years

Cited by 33 publications

References 98 publications

Plant diversity increases predation by ground‐dwelling invertebrate predators

Plant diversity increases predation by ground‐dwelling invertebrate predators

Plant traits are poor predictors of long-term ecosystem functioning

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

Contact Info

Product

Resources

About