The Influence of Tree Diversity on Natural Enemies—a Review of the “Enemies” Hypothesis in Forests

@article{Staab2020TheIO,
  title={The Influence of Tree Diversity on Natural Enemies—a Review of the “Enemies” Hypothesis in Forests},
  author={Michael Staab and Andreas Schuldt},
  journal={Current Forestry Reports},
  year={2020},
  volume={6},
  pages={243 - 259}
}
Natural enemies are an important component for forest functioning. By consuming herbivores, they can be effective top-down regulators of potential pest species. Tree mixtures are generally expected to have larger predator and parasitoid populations compared to monocultures. This assumption is based on the “enemies” hypothesis, a classical ecological concept predicting a positive relationship between plant diversity (and complexity) and natural enemies, which, in turn, should increase top-down… 

Figures and Tables from this paper

Meta-analysis of tree diversity effects on the abundance, diversity and activity of herbivores’ enemies
TLDR
A significant positive effect of forest tree diversity on natural enemy abundance and diversity but not on their activity is found, and potential avenues for strengthening forest resistance to the growing threat of herbivorous insects are outlined.
Tree species richness, tree identity and non-native tree proportion affect arboreal spider diversity, abundance and biomass
TLDR
An important finding of the analyses is that potentially negative effects of non-native Douglas fir on arboreal arthropods were not more severe than effects of native conifers that are planted outside of their natural habitats.
Does the “Enemies Hypothesis” operate by enhancing natural enemy evenness?
TLDR
It is suggested that greater consideration of predator-predator interactions and local biodiversity effects could help explain inconsistent relationships between landscape diversity and herbivore suppression.
The significance of tree-tree interactions for forest ecosystem functioning
Abstract Global change exposes forest ecosystems to many risks including novel climatic conditions, increased frequency of climatic extremes and sudden emergence and spread of pests and pathogens. At
Insect herbivory on urban trees: Complementary effects of tree neighbours and predation
TLDR
It is indicated that tree diversity is a key determinant of multitrophic interactions between trees, herbivores and predators in urban environments and that managing tree diversity could contribute to pest control in cities.
Multi-trophic communities re-establish with canopy cover and microclimate in a subtropical forest biodiversity experiment
TLDR
Although maximizing tree diversity is an important goal of reforestation and forest conservation, rapid closure of canopies is also important for re-establishing communities of forest bees, wasps and their natural enemies.
Disturbance by invasive pathogenic fungus alters arthropod predator - prey food webs in ash plantations.
TLDR
The results support the view that H. fraxineus represents a threat to the biodiversity and ecosystem functioning in the simplified ecosystems of ash plantations.
Non-native Douglas fir (Pseudotsuga menziesii) promotes sentinel prey attack rates in Central European forests
TLDR
Indirect effects of Douglas fir were stronger than direct tree identity and proportion effects, with both increased light availability and understory vegetation complexity promoting attack rates, and promoting vegetation complexity and light availability by thinning, or planting more open Douglas fir stands with a lower stem density could help to promote pest control in forest stands of non-native tree species.
What shapes ground beetle assemblages in a tree species-rich subtropical forest?
TLDR
Ground beetles seem to respond differently to environmental variables than ants and spiders, two other predominantly predatory arthropod groups that were studied on the same plots in the study area and which showed distinct relationships with woody plant richness.
Diversity, Abundance, and Distribution Patterns of Natural Enemy Insects on Chili (Capsicum annum L.) in Bincau Village, Banjar Regency, South Kalimantan
Chili is a widely cultivated plant by the community because of its profit. Currently, in maintaining the quality of chili, people commonly use a lot of pesticides. In contrast, naturally, there are
...
1
2
...

References

SHOWING 1-10 OF 173 REFERENCES
Predator Diversity and Abundance Provide Little Support for the Enemies Hypothesis in Forests of High Tree Diversity
TLDR
The results provide little support for the enemies hypothesis—derived from studies in less diverse ecosystems—of a positive relationship between predator and plant diversity, and question whether stronger top-down control of food webs can be expected in the more plant diverse stands of the forest ecosystem.
Does plant diversity increase top–down control of herbivorous insects in tropical forest?
TLDR
It is concluded that in tropical forests, top–down control of herbivorous insects in the understory vegetation is affected by a combination of plant diversity, plant species composition and structural features of the plant community.
Top-down pressure by generalist and specialist natural enemies in relation to habitat heterogeneity and resource availability
TLDR
It is found that a higher tree density increased the predation by generalists on sawfly larvae in stands with endemic sawfly densities, and Parasitoids were less successful in standsWith endemic saw fly densities.
Mixed forests to mitigate risk of insect outbreaks
ABSTRACT The majority of agricultural and forest production systems are typically simplified systems and therefore thought to be sensitive to disturbance. Ecosystems might be less sensitive to
Effects of Natural Enemy Biodiversity on the Suppression of Arthropod Herbivores in Terrestrial Ecosystems
TLDR
A meta-analytic synthesis shows a significant overall effect of enemy richness increasing top-down control of herbivores, which is consistent in agricultural studies conducted in tropical versus temperate zones, in studies using caged versus open-field designs, but not so in nonagricultural habitats.
Testing the enemies hypothesis in forest stands: the important role of tree species composition
TLDR
The results provide only partial support for the enemies hypothesis, and suggest that it is both tree species composition and species diversity which affect herbivore survival and predation.
Non-native tree species (Pseudotsuga menziesii) strongly decreases predator biomass and abundance in mixed-species plantations of a tree diversity experiment
TLDR
The results indicate that increasing tree species richness does not necessarily promote characteristics of natural enemy assemblages relevant for pest control in forests and thus not all functions that may be important in a multi-functional management context are likely to be important.
Tree diversity promotes generalist herbivore community patterns in a young subtropical forest experiment
TLDR
This study suggests that generalist herbivores can be crucial for trophic interactions in species-rich forests, and indicates that promoting pest control through stand diversification might require a stronger focus on identifying the best-performing tree species mixtures.
Tree diversity has contrasting effects on predation rates by birds and arthropods on three broadleaved, subtropical tree species
TLDR
The results point to an important role of species-specific and density-dependent mechanisms in modifying the consequences of biodiversity loss on top-down effects in forest ecosystems, and indicate that low tree density reduced arthropod predator abundances and predation rates, but that negative effects were compensated for in more diverse tree mixtures by a functionally more diverse predator community.
Tree diversity is key for promoting the diversity and abundance of forest‐associated taxa in Europe
TLDR
The results clearly show the high value of mixed forest stands for multiple forest‐associated taxa and indicate that multiple dimensions of tree diversity (taxonomic and functional) are important, suggesting that forest management can promote high diversity across taxa.
...
1
2
3
4
5
...