ContextImproving the welfare outcomes for captured animals is critically important and should underpin ‘best-practice’ trapping. Most Australian States and Territories have regulations and guidelines that form a legal framework for the maximum number of hours an animal can be restrained in a trap. Because servicing all traps within preferred time frames (less than 24 h) can be logistically difficult or is considered undesirable for efficacy reasons, some jurisdictions have adopted relatively long trap-checking intervals (up to 72 h).

AimsWe developed and tested the signal transmission and alert efficacy of a foot hold-trap alert system, based on Celium technology, so as to advise trappers of the activation of individual foot-hold traps, even in remote locations.

MethodsWe refined the Celium trap-alert system and designed a below-ground wireless node that transmits a message via satellite or by using the cellular system when a foot-hold trap is sprung. We tested signal transmission and alert efficacy in three locations, with a focus in Australia.

Key resultsTransmission of signals from nodes to hubs and to a smart-phone application were used to resolve interference problems and to identify signal limitations and strengths. During the capture of 34 dingoes, 91% of captures resulted in an alert being received. False negatives were attributed to technical issues with nearby transmitters swamping signals, and software problems that have since been resolved. In 40 captures of dogs and foxes, only one trap-alert transmitter (mole) was uncovered by a target animal and no devices were damaged by animals post-capture.

ConclusionsThis cable-less trap-alert system successfully uses both cellular and satellite networks to transmit messages from desert and coastal locations to trappers, in Australia. We confirmed that this trap-alert system is not detected by target predators in the areas tested and can be effectively used to alert trappers when traps have been sprung.

ImplicationsThis trap-alert system provides a tool to improve welfare outcomes for trapped target and non-target animals through Australia and New Zealand and wherever trapping occurs. It, furthermore, provides a solution to checking traps daily when the distance to and between traps cannot be covered within an appropriate time frame. Although trap alerts can never replace the value of daily trap checking by the trapper, they provide a solution to a management problem, namely, one of accessibility to sites.

Context. Precise and accurate estimates of animal numbers are often essential for population and epidemiological models, as well as for guidance for population management and conservation. This is particularly true for threatened species in landscapes facing multiple threats. Estimates can be derived by different methods, but the question remains as to whether these estimates are comparable.

Aims. We compared three methods to estimate population numbers, namely, distance sampling, mark–recapture analysis, and home-range overlap analysis, for a population of the iconic threatened species, the koala (Phascolarctos cinereus). This population occupies a heavily fragmented forest and woodland habitat on the Liverpool Plains, north-western New South Wales, Australia, on a mosaic of agricultural and mining lands.

Key results. All three methods produced similar estimates, with overlapping confidence intervals. Distance sampling required less expertise and time and had less impact on animals, but also had less precision; however, future estimates using the method could be improved by increasing both the number and expertise of the observers.

Conclusions. When less intrusive methods are preferred, or fewer specialised practitioners are available, we recommend distance sampling to obtain reliable estimates of koala numbers. Although its precision is lower with a low number of sightings, it does produce estimates of numbers similar to those from the other methods. However, combining multiple methods can be useful when other material (genetic, health and demographic) is also needed, or when decisions based on estimates are for high-profile threatened species requiring greater confidence. We recommend that all estimates of population numbers, and their precision or variation, be recorded and reported so that future studies can use them as prior information, increasing the precision of future surveys through Bayesian analyses.

Context. The shore-based survey is a common, non-invasive, and low-cost method in marine mammal science, but its scientific applications are currently limited. Such studies typically target populations whose distributions are not random with respect to nearshore sites and involve repeated scans of the same area from single, stationary platforms. These circumstances prohibit the use of classic distance sampling techniques for estimating animal densities or distributions, particularly the derivation of a detection function that describes the probability of detecting targets at various distances from the observer.

Aims. Here, we present a technique for estimating land-based detection functions, as well as quantifying uncertainty in their parameterisation, on the basis of the range-specific variability of observations from one scan to the next.

Methods. This Bayesian technique uses Monte Carlo simulation to determine the likelihood of thousands of candidate detection functions, then conducts weighted sampling to generate a posterior distribution estimate of the detection function parameterisation. We tested the approach with both archival and artificial datasets built from known detection functions that reflect whale and porpoise detectability.

Key results. When the base distribution of targets was random, the whale detection function was estimated without error (i.e. the difference of the median of the posterior and the true value was 0.00), and the porpoise detection function was estimated with an error equal to 4.23% of the true value. When the target base distribution was non-random, estimation error remained low (2.57% for targets concentrated offshore, 1.14% when associated with nearshore habitats). When applied to field observations of humpback whales and Dall’s porpoises from a land-based study in northern British Columbia, Canada, this technique yielded credible results for humpback whales, but appeared to underestimate the detectability of Dall’s porpoises.

Conclusion. The findings presented here indicate that this approach to detection function estimation is appropriate for long-running surveys in which scan regularity is high and the focus is on large, slow-moving, low herd-size, and easily detectable species.

Implications. The derivation of a detection function is a critical step in density estimation. The methodology presented here empowers land-based studies to contribute to quantitative monitoring and assessment of marine mammal populations in coastal habitats.

Context. Wildlife biologists accumulate large quantities of images from remote cameras, which can be time- and cost-prohibitive to archive and analyse. Remote-camera projects would benefit from not setting cameras longer than needed and not analysing more images than needed; however, there is a lack of information about optimal deployment time required for remote-camera surveys to estimate ungulate abundance.

Aims. The objective was to estimate abundance of adult females in a population of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) in Utah, USA, from 2012 to 2014, and determine whether this type of study can be conducted more efficiently. Because females are the most important cohort for population growth, remote cameras were set at three water sources and mark–resight models in Program MARK were used.

Methods. We compared estimated abundance of collared and uncollared females by number of days cameras were set using 31 replicated abundance estimates from each year starting 1 July. Each replicated estimate used a different number of days and photographs from a 62-day sampling period (1 July to 31 August).

Key results. Abundance estimates ranged from 44 to 98 animals. Precise estimates of abundance, however, were obtained with only 12 days of sampling in each year. By analysing only 12 days of images rather than 62 days in all years, the estimated mean of 58 adult females would have changed by only 7 individuals (±4 individuals, range = 3–10 animals), the s.e. would have increased by a mean of only 4 individuals (±1.6, range = 2.0–5.2 individuals) and a mean of only 18% (±10.5%, range = 8–29%) of images would have been analysed. Across the study, analysis of >23 000 (>80%) images could have been avoided, saving time and money.

Conclusions. The results indicate that an asymptotic relationship exists between estimated abundance of female bighorn sheep and remote-camera deployment time.

Implications. The mark–resight methods used in the present study would work for other ungulates in which individuals are radio collared or marked using remote cameras set at water sources, trail crossings or mineral licks. These findings can help researchers reduce cost of setting, servicing, archiving and analysing photographs from remote cameras for ungulate population monitoring.

Context. The disruption of normal activities by humans (i.e. ‘anthropogenic disturbance’) can have important behavioural, physiological and population effects on coastal birds. These negative effects include increased vigilance, increased energy expenditure and reduced nesting success. To overcome this, separation distances (e.g. buffers and setbacks) are often used to separate threatening stimuli, such as humans, from wildlife. However, in most instances the determination of separation distances are based on little empirical information. This is particularly true for Africa, which supports huge populations of Palearctic migrant shorebirds.

Aim. To determine suitable separation distances that will reduce anthropogenic disturbance to the coastal bird community at West Coast National Park, South Africa.

Methods. The distance at which a behavioural response (i.e. flight initiation distance, FID) occurred among 15 common coastal bird species when presented with an approaching human was measured. Linear mixed-effects models were used to determine the relationship between FID and body size, migratory status, intraspecific flock size, flock species richness, foraging behaviour and several environmental covariates.

Key results. Body mass was significantly and positively correlated with FID, indicating that larger birds are more sensitive to the anthropogenic stimulus. Furthermore, it was shown that migratory birds had longer FIDs, suggesting that they are less risk tolerant compared with resident birds. The distance at which the approach was initiated (i.e. the start distance, SD) was also significantly and positively correlated with FID, supporting the hypothesis that birds will flush early to avoid the potential negative consequences of fleeing too late. Finally, there was a novel significant effect of increasing wind speed on increasing FID, suggesting a thermoregulatory trade-off. There was no effect of foraging behaviour, flock size or flock composition on FID.

Conclusion. Based on these data, buffer distances for tidal habitats at West Coast National Park should be set at ∼170 m.

Implications. Improved understanding of FID, and the morphological and behavioural predictors thereof, will enable West Coast National Park and other protected areas to designate separation distances or buffer zones that reduce the negative effects of anthropogenic disturbance on shorebird communities.

Context. Marine turtle eggs incubate in dynamic beaches, where they are vulnerable to both saltwater and freshwater flooding. Understanding the capacity for marine turtle eggs to tolerate flooding will aid management efforts to predict and mitigate the impacts of climate change, including sea-level rise and increases in coastal flooding.

Aims. Evaluate the interactive effects of flooding duration and incubation stage on the hatching success of loggerhead turtle (Caretta caretta) eggs.

Methods. Groups of 20 eggs from multiple clutches were incubated in plastic containers in a beach hatchery. Eggs at six stages of incubation (0, 1, 2, 4, 6 and 7 weeks post-oviposition) were excavated from the hatchery and exposed to saltwater or freshwater flooding for seven durations of time (0, 1, 2, 3, 6, 24 or 48 h). Containers of eggs were either submerged in a bucket of water or left outside of the bucket (control; no flooding) for their designated duration, allowed to drain, then reburied in the hatchery. Following hatchling emergence, the hatching success of each group of eggs was evaluated.

Key results. Freshly laid eggs and eggs on the verge of hatching exposed to any flooding and all eggs exposed to extended periods of flooding (24 and 48 h) suffered complete mortality. Eggs at 20–80% development exposed to short periods of flooding (1–6 h) maintained high hatching success that was statistically equivalent to control eggs, while eggs at <20% and >80% development exhibited significant decreases in hatching success.

Conclusions. Marine turtle eggs in the middle of incubation can tolerate saltwater and freshwater flooding for up to 6 h. Outside of this period or when flooding is longer, disruption of gas concentrations and osmotic gradients in the egg chamber can lead to embryonic mortality. These findings have reinforced concerns regarding the capacity for marine turtle populations to continue to function as rising sea levels and increases in coastal flooding alter the hydrology of nesting beaches.

Implications. As current and predicted climate change threatens the suitability of the incubation environment used by marine turtles, corrective actions to maximise hatching success need to be taken before the eggs are flooded.

Context. Acoustic communication is common in some animal groups, with an underlying function typically associated with mating or territoriality. Resolving the function of calls is valuable both in terms of understanding the fundamental biology of the species and, potentially, for applied reasons such as detection. Early detection is a key step in exclusion and eradication of invasive species, and calling behaviour can be used in this regard. The Asian house gecko (Hemidactylus frenatus) is one of a minority of lizards that uses acoustic communication. However, despite how conspicuous the call is, its function remains poorly resolved. It is also one of the world’s most invasive species, with exclusion via early detection being the key form of control.

Aims. The aim was to resolve calling patterns and underlying function of the loud, multiple-chirp call (‘chik, chik, chik…’) in H. frenatus, in the context of using the results for developing effective methods for detection of new and establishing populations.

Methods. The calls of wild H. frenatus were recorded to assess peaks in calling activity. Also, laboratory experiments were performed to determine which individuals call, what causes them to call and the degree of call variation among individuals.

Key results. Assessment of calling behaviour in the wild revealed greater calling activity in warmer months, and five- to 10-fold peaks in calling activity at sunset and 30 min before sunrise. Laboratory experiments revealed that calls were uttered exclusively by males and primarily by adults (although juveniles can call). Males called more when they were paired with females as opposed to other males. Calls differed among geckos, including the expected negative correlation between dominant frequency and body size.

Conclusions. The results suggest that the multiple-chirp call functions as a territory or sexual broadcast by males, perhaps containing information such as body size.

Implications.Detection success can be maximised by performing acoustic surveys (by human or machine) during the calling peaks at 30 min before sunrise and at sunset, particularly during warm nights. However, these surveys will only be effective for detecting adult males. The results also suggest that good quality recordings could potentially be used to identify individual geckos.

ContextUngulate prey can use increased vigilance to reduce their risk of predation, but little is known of the combined and interactive risk effects from humans and wolves in determining ungulate behaviour across time and space. Understanding the interplay between these risk effects is increasingly important, considering the recolonisation of several large carnivores to more human-dominated landscapes in Europe.

AimThe aim of the present study was to assess the vigilance behaviour expressed by red deer (Cervus elaphus) in response to both humans and wolves in the Polish Białowieża Forest.

MethodsUsing a camera-trap transect, the effect of distance to human settlements, hunting season, patterns of space use by wolves (Canis lupus), canopy openness, canopy height, time of day, as well as sex/age of individuals, on the vigilance behaviour observed in red deer was studied using a model-selection approach.

Key resultsWe did not find a clear effect of patterns of space use by wolves or distance to human settlements on red deer vigilance behaviour at the landscape scale. However, red deer showed increased vigilance during the hunting season and during the day outside of protected areas and reserves, because disturbance from human hunters is highest. Conversely, we also found that red deer were more vigilant at night within more protected areas, which is likely to be explained by the increased activity of wolves because human activity is strictly limited.

ConclusionsOur study showed that vigilance behaviour of red deer in Białowieża Primeval Forest is more driven by human hunting than by the frequency of wolf presence at a landscape scale. This could be explained by the higher temporal and spatial predictability of human hunting activities than wolf risk. We found that patterns of wolf space use, as opposed to the omnipresent fear effects from humans, had only localised effects by increasing vigilance levels during night hours in non-hunting areas of the forest. The reverse was observed outside of protected reserves. Understanding how prey species respond to this new combination of risk from natural predators and humans, is increasingly important in a landscape where human risk is becoming ever more potent and carnivores recolonise.

Context. Pitfall trapping is a standard technique for indexing surface active invertebrates on beaches, and underpins the study of sandy shore ecology. However, pitfall traps may pose a risk to the flightless young of beach-nesting birds, which may fall into such traps and potentially die.

Aim. The aim of the present study was to compare the invertebrates captured in standard pitfall traps with those captured in pitfall traps fitted with one of three potential shorebird exclusion devices. Ideally, the traps with exclusion devices would perform similarly to the standard traps (to enable inter-study comparability) and would detect ecological gradients, such as those evident in invertebrate assemblages between the beach and foredune.

Methods. A systematic array was deployed, using 64 pitfall traps of four types: three types with bird-exclusion devices (a mesh cover, a fence around the rim and a low roof); and a standard pitfall trap with no exclusion device. Pitfall traps were stratified across two habitat types (upper beach and foredune) and were simultaneously deployed to control for environmental and other variables.

Results. Each trap type was broadly comparable in terms of the assemblage of invertebrates recorded, with two exceptions: (1) there was a slightly lower species diversity in mesh than in roofed traps; and (2) the assemblage captured differed between roofed and fenced traps, with the former trapping more isopods and amphipods. No trap type differed from control traps, and all differentiated an ecological gradient between beach and foredune. Thus, any trap design option we tested met our criteria.

Conclusions and implications. The present study shows that bird-exclusion devices for pitfall traps need not compromise trap performance, comparability or utility.

Context. Understanding the relationships between land use and anuran habitat selection would help make conservation-management and habitat-restoration decisions. However, only a few studies have investigated all the available amphibian habitats in terrestrial and aquatic environments.

Aims. The objective of the present study is to assess the associations between different land-use types and individual anuran species in a traditional agricultural area. We also hypothesise that connectivity and land-use heterogeneity are important in determining species richness.

Methods. We conducted monthly roadside calling surveys at 71 sites in the Sun Moon Lake (SML) region in central Taiwan during 2008–2010. Non-metric multidimensional scaling (NMDS) with envfit was used to investigate the relationships between land-use characteristics and anuran assemblage. We use a site-occupancy model to assess the associations between land use and occupancy rate of each species. Generalised linear regression with Poisson distribution was used to assess the relationships among connectivity, land-use heterogeneity and species richness.

Key results. In total, 19 species in five families were detected by roadside calling surveys. The NMDS results showed anuran assemblages in the SML region being distributed through an environmental gradient from those most dominated by agricultural land to forest-dominant sites. According to site-occupancy models, the occupancy rates of anurans were mainly correlated with proportion of agricultural land, grassland and distance to river. The species richness was positively correlated with land-use heterogeneity.

Conclusions. The results showed that the distributions of anurans largely depended on surrounding land-use types in the terrestrial environment. The major trend of anuran assemblages in the traditional agricultural area was dependent on the transition from forest to agricultural land.

Implications. The data suggested that land-use heterogeneity should be a primary consideration for increasing amphibian species richness.