A rapid soundscape analysis to quantify conservation benefits of temperate agroforestry systems using low-cost technology

Abstract

Quantifying the impacts of agroforestry systems (AFS) on habitat conservation remains a challenge due to difficulties in accounting for differences in scales, AFS configurations, and inadequate measures of species dynamics within practical time frames. The field of soundscape ecology offers new perspectives and tools to efficiently collect information on species richness and has a potential to be used as a holistic measure for indicating changes in habitat conditions. The objective of this investigation was to conduct a rapid soundscape assessment using low-cost technology and evaluate the efficacy of using sounds as an indicator for monitoring and assessing species richness within AFS. A series of low-cost recorders were placed within two AFS (pecan alley crop and silvopasture) and two control habitats (natural forest and soybean monoculture). The acoustic complexity index (ACI) was used as the metric to quantify the sonic environment. Results indicated a weak, but significant relationship (R2 = 0.30) between the ACI and overall structural complexity, measured using median heights, across different land-use systems. There was a stronger relationship (R2 = 0.53) between the ACI metric and soundscape composition, which was defined by overall species richness. This study demonstrated the usefulness of conducting a rapid, low-cost soundscape analysis that quantified the effects of different land-use systems on species richness. This research also helped provide evidence of the significance of AFS as an integrative land-use system with beneficial characteristics that have potential to promote both production and ecological conservation.