Deforestation homogenizes tropical parasitoid-host networks

Area of Science:

• Ecology
• Conservation Biology
• Biodiversity Research

Background:

• Human activities, such as deforestation, are known to cause biotic homogenization, leading to a loss of regional diversity across various taxa.
• The impact of these human activities on the homogenization of species interaction networks, like food webs, remains largely unexplored.

Purpose of the Study:

• To investigate whether deforestation leads to the homogenization of species interaction networks in tropical habitats.
• To understand the mechanisms driving network homogenization, including changes in community composition and consumer foraging success.

Main Methods:

• Utilized 48 quantitative parasitoid-host networks across five tropical habitats, replicated in space and time.
• Analyzed both quantitative and binary (presence-absence) network data to assess interaction composition and structure.
• Examined alterations in consumer foraging success and mean consumer and prey body size in relation to habitat type.

Main Results:

• Deforestation significantly homogenized parasitoid-host network structure at a regional level, increasing similarity between rice and pasture sites compared to forested habitats.
• Network homogenization was linked to altered consumer foraging success and indirectly to changes in mean consumer and prey body size.
• Binary network analysis yielded similar patterns, suggesting interaction presence-absence data can detect network homogenization.

Conclusions:

• Tropical agroforestry systems can maintain diverse parasitoid-host networks, but canopy cover removal homogenizes network structure in space and, to a lesser extent, in time.
• Spatiotemporal homogenization of interaction networks may negatively affect coevolutionary dynamics and regional ecological resilience.
• Network homogenization effects may not be predictable solely from changes within individual trophic levels.