Forest disturbance and arthropods: small‐scale canopy and understory disturbances alter movement of mobile arthropods

The role of canopy structure on the diversity and function of arthropods in coffee agroscapes of the Northern Andes

Increasing sustainable productive activities to provide food, fiber, and energy is a global necessity for an increasingly populated planet. However, managing productive landscapes requires integrative approaches in which changes in diversity, microhabitat effects and managing conditions are assessed. We analyzed patterns of arthropod diversity, composition, and functional guilds in response to changes in canopy structure (solar radiation, geometry, and openness) in sun and shade coffee plantations in a coffee-producing landscapes of the northern Andes. We found that the response of the arthropod community varied according to the variables analyzed. On the one hand, we found that sun coffee plantations have higher arthropod richness and diversity. However, shaded coffee plantations show higher abundance and biomass values. Similarly, when the arthropod community was separated by functional guilds, a positive effect of solar radiation was observed in shade coffee plantations. Our results suggest that sun coffee plantations are not necessarily an inhospitable environment for arthropod diversity but may be so in terms of ecosystem functions. We conclude that a wider range of variables should be included to get a clearer picture of which productive landscape designs may be best for conserving arthropod biodiversity and ecosystem functions in productive landscapes.

Tree diversity enhances predation by birds but not by arthropods across climate gradients

Tree diversity can promote both predator abundance and diversity. However, whether this translates into increased predation and top-down control of herbivores across predator taxonomic groups and contrasting environmental conditions remains unresolved. We used a global network of tree diversity experiments (TreeDivNet) spread across three continents and three biomes to test the effects of tree species richness on predation across varying climatic conditions of temperature and precipitation. We recorded bird and arthropod predation attempts on plasticine caterpillars in monocultures and tree species mixtures. Both tree species richness and temperature increased predation by birds but not by arthropods. Furthermore, the effects of tree species richness on predation were consistent across the studied climatic gradient. Our findings provide evidence that tree diversity strengthens top-down control of insect herbivores by birds, underscoring the need to implement conservation strategies that safeguard tree diversity to sustain ecosystem services provided by natural enemies in forests.

Vertical Stratification and Seasonal Dynamics of Coleoptera in Open Biotopes of Forest Ecosystems (Centre of European Russia)

There are few studies on the vertical distribution and seasonal activity of arthropods in open habitats (in glades) in temperate forests due to methodological problems associated with the arrangement of certain structures for trapping. However, glades in forests are places of significant biodiversity of native animals, which are attracted to such areas by the possibilities of nutrition, reproduction, and wintering. The research was carried out on the territory of the Republic of Mordovia (the center of the European part of Russia). Fermental traps (bait—fermenting beer with sugar) were used to collect Coleoptera. They were installed on a special structure at heights of 2, 4, 6, 8, and 10 m. The collections were carried out from May to October 2020 in a glade with an area of 0.93 hectares in a deciduous forest. At the end of the research, 745 specimens of 80 species were registered from 30 Coleoptera families. The greatest species diversity was recorded in Nitidulidae (11 species), Cerambycidae (10 species), Scarabaeidae (7 species), Elateridae, Coccinellidae, and Curculionidae (5 species each). The greatest species diversity (53 species) and numerical abundance were obtained at a height of 2 m, and the smallest one (16 species) at a height of 10 m. The largest differences in the Jaccard similarity index were obtained between samples from a height of 2 and 10 m. The maximum values of the Shannon index and the minimum values of the Simpson index were recorded at the height of 2 m. The most significant relative number of saproxylic species was obtained at a height of 4 m. The relative number of anthophilic species was minimal at a height of 10 m. The seasonal dynamics of Coleoptera abundance were the same at different heights and the highest abundance was observed in late May and early June. However, the seasonal dynamics were different for some Coleoptera species in the glade located and inside the forest. Our data confirm the relevance of sampling in open biotopes at different heights in the study of arthropod biodiversity.