Assessing population trends is a basic prerequisite to carrying out adequate conservation strategies. Selecting an appropriate method to monitor animal populations can be challenging, particularly for low‐detection species such as reptiles. This study compares 3 detection‐corrected abundance methods (capture–recapture, distance sampling, and N‐mixture) used to assess population size of the threatened Hermann's tortoise. We used a single dataset of 432 adult tortoise observations collected at 118 sampling sites in the Plaine des Maures, southeastern France. We also used a dataset of 520 tortoise observations based on radiotelemetry data collected from 10 adult females to estimate and model the availability (g0) needed for distance sampling. We evaluated bias for N‐mixture and capture–recapture, by using simulations based on different values of detection probabilities. Finally, we conducted a power analysis to estimate the ability of the 3 methods to detect changes in Hermann's tortoise abundances. The abundance estimations we obtained using distance sampling and N‐mixture models were respectively 1.75 and 2.19 times less than those obtained using the capture–recapture method. Our results indicated that g0 was influenced by temperature variations and can differ for the same temperature on different days. Simulations showed that the N‐mixture models provide unstable estimations for species with detection probabilities <0.5, whereas capture–recapture estimations were unbiased. Power analysis showed that none of the 3 methods were precise enough to detect slow population changes. We recommend that great care should be taken when implementing monitoring designs for species with large variation in activity rates and low detection probabilities. Although N‐mixture models are easy to implement, we would not recommend using them in situations where the detection probability is very low at the risk of providing biased estimates. Among the 3 methods allowing estimation of tortoise abundances, capture–recapture should be preferred to assess population trends. © 2013 The Wildlife Society.

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Because they have high longevity and a weak dispersal capacity, chelonians are known to be highly impacted by fire. We investigated the immediate demographic consequences of a wildfire occurring in 2009 on a population of Hermann's tortoises Testudo hermanni in the Plaine des Maures in southeastern France using the multistate capture–recapture method. Over two years (2009 and 2010), 108 adult individuals were marked. Survival probability was higher in the unburned (0.99) than in the burned area (0.43). The inter-annual transition probability from the burned to the unburned area was high (0.72). These results show that fire affects survival by immediately killing individuals and by inducing small-scale movements from burned to unburned areas.

1. Entomological studies often aim to estimate species distribution, community composition, or species-richness patterns. False absences can, however, bias these estimates and should consequently not be overlooked in insect studies. Multi-species occupancy models (MSOMs) afford a flexible solution to cover the main topics in ecological entomology while dealing with detectability issues. 2. We sampled Orthoptera communities at 81 mountain grasslands sites in France, using three sampling techniques: sighting, listening, and sweep netting. Five plots were sampled per site. This sampling design allowed MSOMs to be used to estimate richness, occupancy, and detection probabilities while accounting for the effect of covariates. We also used MSOMs to evaluate the efficiency of the survey design and to assess the effects of sampling optimisation. 3. The estimates obtained for altitudinal distribution were reliable, with known species distributions confirming the relevance of MSOMs to model the effects of covariates on Orthoptera communities. The species-specific detection probability was often less than one and varied with the detection technique used and the grass height, confirming the need to deal with detection issues in orthopteran studies. 4. We estimated an inventory completeness superior to 0.80 for 93% of the sites, and an overall detection probability superior to 0.95 for 52% of the species, suggesting the sampling design was suitable for studying occupancy in Orthoptera communities. We also found that the sweep netting step may be omitted or the number of plots reduced without affecting species detectability or inventory completeness. Those recommendations may help to optimise future sampling strategies.