Suggestions for extending, expanding, and integrating passive acoustic monitoring programs

Passive acoustic monitoring (PAM) has entered the ecological mainstream, and further growth is likely. How can the growth of PAM be guided for maximum research and conservation impact? I offer suggestions for how terrestrial PAM programs can proactively plan for extension (growth over time), expansion (growth over space and/or species surveyed), and integration (growth in the number of teams involved, leading to synthesis of data from multiple programs). The three modes of growth are independent, though expansion in space is usually predicated on concurrent extension. Key points include: (1) hardware and recording choices are critical because they irrevocably define the limits of the audio dataset, the characteristics of the audio, and the sampling unit itself; (2) analysis software is less critical because audio can be reanalyzed with new tools; (3) long-term planning for the retention of experienced personnel (e.g., via pathways for professional advancement) and database development (e.g., building a streamlined bioacoustics pipeline with purpose-built output files) are important; and (4) the interpersonal aspects of multi-project syntheses are likely to be critical to integration, though statistical challenges (not addressed at length herein) may also be formidable without careful planning. Careful growth of passive acoustic monitoring programs can lead to new insights for ecology and conservation; under-planned growth can lead to wasted resources and missed opportunities – steep costs in an era of limited resources and rapid change.