Ecological interactions in extant ecosystems

Project members: Danielle Rappaport, Anshuman Swain, William F Fagan and Douglas C. Morton

Status: Published in PNAS

Safeguarding tropical forest biodiversity requires tractable solutions for monitoring the legacy of human activity on ecosystem services beyond carbon. Remaining forests along the Amazon development frontier have been exposed to increasing degradation from fire and logging, but the long-term consequences for biodiversity remain poorly understood. Together, the taxonomic diversity of tropical forests, and spatial and temporal diversity of degradation impacts pose major monitoring challenges. Technological advances are needed to characterize time-dependent shifts in community composition across broad spatial extents. Here, we combined data from diurnal acoustic surveys, airborne lidar, and satellite time series along a successional gradient of logged and burned forests in the southern Amazon to identify acoustic markers of fire and logging and test the Acoustic Niche Hypothesis (ANH) for proxies of habitat condition using an array of statistical and network-based analyses. Our findings contradict expectations from the ANH that more intact habitats harbor acoustic communities that occupy more transmission space (as defined by time and frequency), even during dawn and dusk chorus. The contrasting patterns of acoustic space infilling in logged and burned forests indicate that biomass recovery is not a consistent proxy for biodiversity recovery, and  analyses of frequency-time network topologies revealed distinct patterns of biotic assembly after logging vis-à-vis fire. Taxonomically inclusive measurements from soundscape data highlight large possible co-benefits to protecting Amazon forests from recurrent fire activity in the face of worsening Amazon drought and human encroachment.

Project members: Cian White, Kate Wootton, Anshuman Swain and Sanja Selakovic

Status: Work in progress; This project came out of a working group at the Winter Workshop on Complex Systems (WWCS) 2020 at Gruyere, Switzerland.

Over the previous two decades, ecologists have been increasingly interested in the stability of ecosystem functions. Understanding the interplay between these ecosystem functions and ecosystem services is key in planning the conservation and maintenance of ecological systems. In this project, we use a food web dynamics model to explore the effects of nutrient input on interactions between various functions and services from a network perspective.