Fig 1.
Three study areas surveyed with multiple camera traps in Maine, USA.
12 sites each composed of five camera traps were deployed in the Scraggly Lake (SL) area during January 2017, 12 sites in the Telos Road/Nahmakanta Public Reserve Lands (TN) from February to March 2017, and 8 sites in the Moosehead Lake (ML) area from late February to March 2017.
Fig 2.
A survey site composed of five camera trap units in a T-configuration to detect terrestrial mammals in Maine, USA.
Detection histories from individual cameras were pooled in five different combinations to assess the impact of survey methods that varied by number of cameras (1–3) and spacing (short, 100 m, or long, 150 m between cameras): 1 unit (camera A), 2 short (cameras B and C), 3 short (A, B, and C), 2 long (D and E) 3 long (B, D, and E).
Table 1.
Definitions of terms used in study design and modeling to assess the influence of different numbers and spacing of camera traps on the detection of mammals in Maine, USA.
Table 2.
Top-ranked occupancy models for six species surveyed with camera trap transects in Maine, USA, 2017.
Fig 3.
Model-averaged estimated detection probabilities and standard errors for camera trap surveys conducted in north and central Maine, USA, during winter 2017.
The detection histories for six species were analyzed for five different potential survey methods of 1–3 camera units spaced short (100 m) or long (150 m). When derived from models including the study area parameter, results are shown for the Telos Road/Nahmakanta Public Reserve Lands, and when models included access type, results are displayed for plowed road access.
Table 3.
Parameter estimates for six mammal species in Maine: is the probability of occupancy,
is the probability of availability for detection on any survey day, and
is the probability of detection with a specific method conditional on availability.
Table 4.
Influence of camera site features on detection probabilities for six mammal species in Maine, USA.