Mark-recapture Techniques Research Articles

Niche partitioning in carabids: single‐tree admixtures matter

Abstract The importance of tree mixtures to the faunal and floral biodiversity of forests has been documented on many occasions, but little is known about the relationships between single‐tree effects, such as litter distribution and carabid beetles. The aim of the study was to investigate the relationship between the occurrence of carabid beetles and the locations of admixed oak trees within a Scots pine (Pinus sylvestris L.) stand. Individuals of four Carabus species were collected in dry pitfall traps in a pine forest with single admixed sessile oaks [Quercus petraea (Matt.) Liebl.]. The capture–mark–recapture technique was used to differentiate carabid beetles by species, gender (female, male), and development stage (imagines, larvae). Three zones of influence were defined according to the distribution of oak leaf litter. The beetle counts from trap data were transformed to a point pattern by means of a random‐field approach where it is assumed that the beetle count per trap is representative of a specified number of single points in the square surrounding the trap. Spatial patterns specific to species, gender, and development stage were observed relative to the oak tree locations. Females and larvae of C. coriaceus and C. hortensis had a high affinity to the oaks, whereas C. violaceus revealed a negative association to the oak trees. No clear trend could be observed for C. arvensis. It was concluded that single‐tree admixtures of oaks affect the spatial patterns of mobile organisms (e.g. Coleoptera) serving as ecological niches in pine forests.

Population size of Aegla longirostri Bond-Buckup and Buckup, 1994 (Crustacea, Decapoda, Anomura): comparison of methods with the mark-recapture technique in closed population

The aim of this study is to estimate the population size of Aegla longirostri Bond-Buckup and Buckup, 1994 in a subtropical low-order stream using the mark-recapture technique. We also tested if the Bayesian model is a promising estimator of population size. Data were collected in two periods, in spring 2010 (seven-day sampling) and in fall 2011(five-day sampling). The animals were sexed, measured, marked in the field, and released in the same spots from which they were collected. During the study period, 445 adults were captured (343 in the spring and 102 in the fall). The estimated population size was 1,005-1,028.8 individuals in the spring and 234-236 in the fall, according to the Schumacher-Eschmeyer and Schnabel methods, respectively. The estimated population size using the Bayesian analysis was 950.13 individuals in the spring and 210.08 in the fall. Although the Bayesian model is a more conservative approach, all methods showed similar and relevant estimations of population size.

Challenges and opportunities for monitoring wild Nile crocodiles with scute mark-recapture photography

The global conservation status of Nile crocodiles (Crocodylus niloticus) was last assessed in 1996. The species presents particular difficulty in monitoring because it can be cryptic, require expertise to handle, and caudal tail tags and transmitters are often lost. Some studies advocate mark-recapture techniques based on photograph identification of the unique scute markings of crocodile tails as a non-invasive means of monitoring their populations. Researchers developed this method with crocodiles in captivity. In this study, we test the technique under field conditions by monitoring crocodiles from 2015 to 2017 in the Sunset Dam in the Kruger National Park. Using a Cormack-Jolly-Seber open population model, we found that the dam may host 15–30 individuals, but that there is a high turnover of individuals and much uncertainty in model outputs. The dam’s population thus has high rates of immigration and emigration. The method proved challenging under field conditions, as there was bias in identifying scute markings consistently. The efficient use of the method requires an exceptional quality of photographic equipment. Animal crypsis, however, remains an issue. In this study, we discuss how to improve the mark-recapture photography methodology, especially to adapt the technique for citizen science initiatives.Conservation implications: Using scute mark-recapture photography presents challenges under field conditions. These challenges require innovative, practical and analytical solutions to successfully use the technique before monitoring programmes, aimed at ensuring the persistence of crocodiles in the wild, can be implemented.

Challenges of implementing Mark-recapture studies on poorly marked gregarious delphinids.

Population parameters of poorly marked gregarious species are difficult to estimate. This is the case for common dolphins (Delphinus sp.), a genus known for its lack of distinctive marks resulting in a low mark ratio. Furthermore, the widespread nature of common dolphins results in low recaptures. We developed reliable photo-identification protocols to ensure accurate identification of individuals in the Hauraki Gulf, New Zealand. These protocols combined the use of nicks and notches and pigmentation patterns for identification and included the development of a distinctiveness threshold. The data were further stratified by the level of distinctiveness of each individual (as distinctive or highly-distinctive). Photo-identification surveys were conducted from January 2010 to December 2013. Mark-recapture techniques were implemented through a POPAN super-population approach to estimate seasonal apparent survival, capture probability and abundance of dolphins. A total of 2,083 unique adult common dolphins were identified, 51.3% were classified as D1 (highly distinctive; n = 1,069) and 48.7% as D2 (distinctive; n = 1,014). Of all individuals identified, 34.3% (n = 704) were re-sighted over subsequent years. The proportion of marked dolphins (when compared to unmarked dolphins) was 26.3% for D1 and 46.4% for D1 & D2, respectively. Apparent survival was estimated at 0.767 (CI = 0.694–0.827) for D1 animals, and 0.796 (CI = 0.729–0.850) for D1 & D2 combined. For D1 only, seasonal abundance varied from 732 (CI = 460–1,177) in autumn 2010 to 5,304 (CI = 4,745–5,930) in spring 2013. While the inclusion of D2 individuals may offer a more precise estimate of total abundance, the inability to determine additional sources of bias (for example, arising from under or overestimated mark ratios) meant that estimates for D1 individuals were deemed the least biased for this population. The photo-identification protocol, stratification of the data and steps taken to eliminate potential model violations provided a useful and novel approach to estimate population parameters for common dolphins. These approaches could be implemented for other large gregarious populations (≥500 individuals) of animals with poor natural markings.

When is enough … enough? Effective sampling protocols for estimating the survival rates of seabirds with mark-recapture techniques

ABSTRACTCapsule: Lower intensity mark-recapture studies, such as those undertaken by citizen scientists, provide an opportunity to improve the spatial representation of survival estimates for birds. Colonial nesting birds are particularly suited to this because, for many species, large numbers of breeding birds and chicks can be located relatively easily. The minimum level of recapture effort required to accurately estimate true survival rates and detect temporal variation largely depended on the respective ringing effort. Therefore, mark-recapture studies should consider both aspects of the field study when setting or adjusting minimum effort guidelines. Furthermore, achieving reliable estimation with short time-series required more intensive survey designs, highlighting the importance of longevity when planning these studies.Aims: To provide minimum guidelines of field effort that can be used to manage smaller projects that monitor survival rates, such as those reliant on citizen scientists.Methods: We conducted a sensitivity analysis that evaluated the statistical power associated with using different mark-recapture survey designs to estimate a fixed ‘true’ survival rate and detect sources of temporal variation and individual heterogeneity within the population.Results: Isolating temporal variation with a good degree (90%) of certainty required the highest levels of survey effort. Based on the assessed survey designs, we recommend studies that have a ten-year trajectory and a recapture rate of 0.6, aim to mark at least 200 new adults per year. The recommended number of marked individuals will decrease if it is possible to achieve higher rates of recapture. Lower rates of juvenile survival and delayed reproduction mean that seabird mark-recapture survey designs that target both chicks and adults offer only marginal improvements in resolving the survival rates of adults, when compared to designs targeting adults only. However, collecting juvenile mark-recapture data provide access to age-specific vital rates that are also valuable for assessing the population dynamics of seabirds.Conclusion: The addition of chicks is unlikely to improve the resolution of adult survival rates markedly, although for species with low natal dispersal and earlier ages of maturity, these data may allow the estimation of other vital rates, such as juvenile survival rates and age of maturity. Implementing minimum effort guidelines potentially enables the effective management of smaller mark-recapture studies, thus minimising the risk that studies fail to achieve the data conditions necessary for robust estimation of survival rates.

Blue Catfish Density and Biomass in a Tidal Tributary in Coastal Virginia

Abstract Ictalurus furcatus (Blue Catfish) provide trophy recreational fishing opportunities in Virginia's tidal rivers; however, potential ecological impacts are of concern. We used mark-recapture techniques and electrofishing in 2007 and 2014 to estimate Blue Catfish density and biomass in Powell Creek. A 66% decline in fish density occurred between 2007 (708 fish/ha) and 2014 (239 fish/ha) and biomass declined by 31% over the same timeframe (266 kg/ha to 185 kg/ha). These findings are supported by long-term monitoring trends in the tidal James River. Here, we provide: (1) data relative to temporal shifts in abundance and biomass, (2) data for use in subsequent population-dynamics analyses, and, (3) points of caution when assuming temporally static populations for introduced species. We demonstrated the feasibility of low-frequency electrofishing and mark—recapture methods to estimate Blue Catfish abundance, and recommend use of the approach where catfish abundance estimates are important.

Fish movement in an Atlantic Forest stream

ABSTRACT Given the importance of fish movement to the dynamics and maintenance of stream dwelling fish communities from the Atlantic Forest, we analysed patterns of fish movement in a coastal stream from Southeastern Brazil, using mark-recapture technique. Displacement distance of each species were presented and discussed considering seasonal (rainy and dry) and body size patterns. We marked 10 species along the stream and recaptured 440 (34.6%) of the 1,270 marked fishes. The species with significant number of upstream moving individuals were Astyanax janeiroensis, Characidium interruptum, Astyanax hastatus, Parotocinclus maculicauda and Awaous tajasica. Only Pimelodella lateristriga presented significant differences between resident and moving individuals. Characidium interruptum and A. tajasica demonstrated greater downstream and upstream movement, respectively, moving up to 2,100 m. Even after controlling for species identity we found no significant correlation between fish length and individual displacement distance. Fishes moved longer distances during the rainy season, in accordance to the breeding season. Patterns of fish movement were in agreement to life-history traits of many of the studied species and can be reflecting specific behaviour and morphologies.

Transcriptomics in the wild: Hibernation physiology in free-ranging dwarf lemurs.

Hibernation is an adaptive strategy some mammals use to survive highly seasonal or unpredictable environments. We present the first investigation on the transcriptomics of hibernation in a natural population of primate hibernators: Crossley's dwarf lemurs (Cheirogaleus crossleyi). Using capture-mark-recapture techniques to track the same animals over a period of 7months in Madagascar, we used RNA-seq to compare gene expression profiles in white adipose tissue (WAT) during three distinct physiological states. We focus on pathway analysis to assess the biological significance of transcriptional changes in dwarf lemur WAT and, by comparing and contrasting what is known in other model hibernating species, contribute to a broader understanding of genomic contributions of hibernation across Mammalia. The hibernation signature is characterized by a suppression of lipid biosynthesis, pyruvate metabolism and mitochondrial-associated functions, and an accumulation of transcripts encoding ribosomal components and iron-storage proteins. The data support a key role of pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) in regulating the shift in fuel economy during periods of severe food deprivation. This pattern of PDK4 holds true across representative hibernating species from disparate mammalian groups, suggesting that the genetic underpinnings of hibernation may be ancestral to mammals.

Effects of habitat quality and access management on the density of a recovering grizzly bear population

Abstract Human activities have dramatic effects on the distribution and abundance of wildlife. Increased road densities and human presence in wilderness areas have elevated human‐caused mortality of grizzly bears and reduced bears' use. Management agencies frequently attempt to reduce human‐caused mortality by managing road density and thus human access, but the effectiveness of these actions is rarely assessed. We combined systematic, DNA‐based mark–recapture techniques with spatially explicit capture–recapture models to estimate population size of a threatened grizzly bear population (Kettle–Granby), following management actions to recover this population. We tested the effects of habitat and road density on grizzly bear population density. We tested both a linear and threshold‐based road density metric and investigated the effect of current access management (closing roads to the public). We documented an c. 50% increase in bear density since 1997 suggesting increased landscape and species conservation from management agencies played a significant role in that increase. However, bear density was lower where road densities exceeded 0.6 km/km2 and higher where motorised vehicle access had been restricted. The highest bear densities were in areas with large tracts of few or no roads and high habitat quality. Access management bolstered bear density in small areas by 27%. Synthesis and applications. Our spatially explicit capture–recapture analysis demonstrates that population recovery is possible in a multi‐use landscape when management actions target priority areas. We suggest that road density is a useful surrogate for the negative effects of human land use on grizzly bear populations, but spatial configuration of roads must still be considered. Reducing roads will increase grizzly bear density, but restricting vehicle access can also achieve this goal. We demonstrate that a policy target of reducing human access by managing road density below 0.6 km/km2, while ensuring areas of high habitat quality have no roads, is a reasonable compromise between the need for road access and population recovery goals. Targeting closures to areas of highest habitat quality would benefit grizzly bear population recovery the most.

Flexible and non-invasive passive integrated transponder (PIT) tagging protocols for tropical freshwater fish species

Passive integrated transponder (PIT) tagging has proven to be an effective mark-recapture technique for many temperate freshwater and marine fish species, but its adaptability to tropical freshwater species remains largely unknown. Nevertheless, many tropical river systems, such as the Mekong in South East Asia, are currently being developed at an unprecedented rate for their relatively abundant water resources. Consequently, there is an urgent need for efficient mark-recapture technologies to understand and assess the impacts of human developments on the movement ecology of tropical freshwater fish species. This paper discusses the development of an optimal protocol for PIT tagging tropical freshwater fishes, using two Mekong River species – Striped catfish (Pangasianodon hypophthalmus) and Goldfin tinfoil barb (Hypsibarbus malcolmi) – as model species.•The PIT tagging protocol is flexible in that it allows the transponders to be placed in a variety of body locations.•The protocol has high tag retention rates (>90%) and is non-invasive, since it does not affect fish growth or mortality rates.•The application of PIT tags can be used to evaluate the success of fishways and other remedial works for supporting crucial life-cycle processes potentially requiring fish passage, such as spawning.

Vertical organization of the division of labor within nests of the Florida harvester ant, Pogonomyrmex badius.

In the Florida harvester ant, Pogonomyrmex badius, foragers occur only in the top 15 cm of the nest, whereas brood and brood-care workers reside mostly in the deepest regions, yet the food and seeds foragers collect must be transported downward 30 to 80 cm to seed chambers and up to 2 m to brood chambers. Using mark-recapture techniques with fluorescent printer's ink, we identified a class of workers that ranges widely within the vertical structure of the nest, rapidly moving materials dropped by foragers in the upper regions downward, and excavated soil from deeper upward. Within the nest, only 5% of foragers were recovered below 20 cm depth, but about 30% of transfer workers and 82% of unmarked workers were found there. Below 70 cm depth, 90% of workers were unmarked, and were probably involved mostly in brood care. During the summer, the transfer workers comprise about a quarter of the nest population, while foragers make up about 40%. Workers marked as transfer workers later appear as foragers, while those marked as foragers die and disappear from the foraging population, suggesting that transfer workers are younger, and age into foraging. The importance of these findings for laboratory studies of division of labor are discussed. The efficient allocation of labor is a key component of superorganismal fitness.

The status of rhinoceroses in South African National Parks

African rhinoceroses (rhinos) experienced a poaching onslaught since 2008 with the epicentre in South Africa where most of the world’s rhinos occur. South African national parks, under the management of South African National Parks (SANParks), are custodian to 49% of South Africa’s white and 31% of the country’s black rhinos. We collated information on rhino population sizes in seven national parks from 2011 to 2015. We include and report on rhino surveys in Kruger National Park during 2014 and 2015. Southwestern black rhinos increased over the study period, which allows SANParks to achieve its contribution to South Africa’s 2020 target of 260 individuals. South-central black rhinos declined over the study period because of poaching in the Kruger National Park, making it difficult for SANParks to realise a 9% increase per annum for its expected contribution to the South African target of 2800 individuals. For southern white rhinos, SANParks requires 5% annual growth for its contribution to the South African target of 20 400 individuals. To continue to evaluate the achievement of these targets, SANParks needs annual population estimates relying on total counts, mark-recapture techniques and block-based sample counts to track trends in rhino populations. SANParks’ primary challenge in achieving its contribution to South Africa’s rhino conservation targets is associated with curbing poaching in Kruger National Park.Conservation implications: The status and trends of rhino species in SANParks highlight key challenges associated with achieving the national targets of South Africa. Conservation managers will need to improve the protection of southern white rhino, while the Department of Environmental Affairs need to be made aware of the challenges specifically associated with not achieving targets for south-central black rhino. Outcomes for south-western black rhino have already realised and the good conservation efforts should continue.

Tributary Use by Imperiled Flannelmouth and Bluehead Suckers in the Upper Colorado River Basin

AbstractHabitat alterations and establishment of nonnative fishes have reduced the distributions of Flannelmouth Sucker Catostomus latipinnis and Bluehead Sucker C. discobolus to less than 50% of their historical ranges in the Colorado River basin. Tributaries are sometimes less altered than main‐stem habitat in the basin and may be important to support various life history processes, but their role in the maintenance of Flannelmouth Sucker and Bluehead Sucker populations is poorly understood. Using mark–recapture techniques, we show tributaries are important habitat for native suckers in the upper Colorado River basin and report three main findings. First, both Flannelmouth and Bluehead suckers likely respond to a thermal cue that initiates spawning movement patterns. Suckers moved into Coal Creek from the White River beginning in mid‐May of 2012 and 2013 to spawn. The majority of sucker spawning movements occurred when water temperatures in White River exceeded 11–14°C and those in Coal Creek were 2.5–4°C warmer, while flows varied between years. Second, based on PIT tag detection arrays, 13–45% of suckers showed spawning site fidelity. Sampling only with fyke nets would have resulted in the conclusion that site fidelity by native suckers was only 1–17%, because nets were less efficient at detecting marked fish. Third, most suckers of both species emigrated from Coal Creek within 48 h after being captured while suckers that were detected only via arrays remained resident for 10–12 d. The posthandling flight response we observed was not anticipated and to our knowledge has not been previously reported for these species. Remote PIT tag antenna arrays allowed for a stronger inference regarding movement and tributary use by these species than what could be achieved using just fyke nets. Tributaries are an important part of Flannelmouth Sucker and Bluehead Sucker life history and thus important to conservation strategies for these species.Received October 7, 2016; accepted March 20, 2017 Published online June 28, 2017

Remediation of upstream passage for migrating Galaxias (Family: Galaxiidae) through a pipe culvert

AbstractMovement through streams is critical for the maintenance of diadromous fish populations. Numerous fish passage improvement techniques exist, and knowledge of their effectiveness is required to conserve target species. An existing 70‐m pipe culvert was considered a barrier to the passage success of young‐of‐year (YOY) Galaxias spp. as a result of high water velocity (0.9 m/s). Water velocity in the pipe culvert was reduced by installing a concrete weir downstream of the culvert. A lateral ridge rock‐ramp fishway was installed to provide for the passage of fish over the weir, and baffles were installed in the upstream portion of the culvert to provide refuge from higher water velocity at this location. A BACI design was used to determine whether passage success, measured using a mark–recapture technique, improved as a result of the remediation works. The probability of successful passage of YOY Galaxias spp. through the culvert increased from 0.03 to 0.41 following remediation works and was similar to levels observed at a control site (0.33). The success of the fishway and baffles at this culvert provides an important case study for managers to adopt this technique to improve fish passage on a broader scale and range of other sites.

Individually mark–mass release–resight study elucidates effects of patch characteristics and distance on host patch location by an insect herbivore

1. How organisms locate their hosts is of fundamental importance in a variety of basic and applied ecological fields, including population dynamics, invasive species management and biological control. However, tracking movement of small organisms, such as insects, poses significant logistical challenges.2. Mass‐release and individual–mark–recapture techniques were combined in an individually mark–mass release–resight (IMMRR) approach to track the movement of over 2000 adult insects in an economically important plant–herbivore system. Despite its widespread use for the biological control of the invasive thistle Carduus nutans, the host‐finding behaviour of the thistle head weevil Rhinocyllus conicus has not previously been studied. Insects were released at different distances from a mosaic of artificially created host patches with different areas and number of plants to assess the ecological determinants of patch finding.3. The study was able to characterize the within‐season dispersal abilities and between‐patch movement patterns of R. conicus. Weevils found host plant patches over 900 m away. Large patches, with tall plants, situated close to the nearest release point had the highest first R. conicus resights. Patch area and plant density had no effect on the number of weevils resighted per plant; however, R. conicus individuals were more likely to disperse out of small patches and into large patches.4. By understanding how R. conicus locates host patches of C. nutans, management activities for the control of this invasive thistle can be better informed. A deeper mechanistic understanding of host location will also improve prediction of coupled plant–herbivore spatial dynamics in general.

Population ecology of a cryptic arboreal snake (Hoplocephalus bitorquatus)

Biologists have traditionally been reluctant to study arboreal snakes due to low rates of capture. Overlooking such taxa can mislead interpretations of population trends for data-deficient species. We used regularly spaced transect searches and standard capture–mark–recapture techniques to describe population structure, growth rates, survival and capture probability in a population of the pale-headed snake (Hoplocephalus bitorquatus) in southern Queensland. We obtained data from 194 captures of 113 individual snakes between 2009 and 2015. Using the Cormack–Jolly–Seber method, we estimated apparent annual survival in subadult snakes at 0.23 ± 0.01 (s.e.) and 0.81 ± 0.08 for adults. Capture probability was estimated at 0.16 ± 0.14 per session in subadult snakes and 0.33 ± 0.06 for adults. Within the red gum forests of our study site, we estimate pale-headed snake density at ~13 ± 7 ha–1. Using von Bertalanffy growth modelling, we predict that snakes reach sexual maturity after about four years and may live for up to 20. Our results suggest that the species is a ‘k’ strategist, characterised by slow maturation and low fecundity. These traits suggest that populations will recover slowly following decline, exacerbating the risk of local extinction.

Measuring the Growth Rate in Three Populations of Larval Lampreys with Mark–Recapture Techniques

AbstractThe growth rate of larval lampreys (ammocoetes) is of critical importance for scientists and managers seeking to better understand, control, and protect lamprey populations. To date, measurements of ammocoete growth have often relied upon indirect methods (e.g., length frequency), but direct measurements of growth rate in wild populations are rare. Lamprey ammocoetes in three streams were individually marked with visible implant elastomer and were subsequently recaptured. Ammocoete growth was variable among sites and among sample events (from −0.035 to 0.18 mm/d; from −0.0022 to 0.012 g/d), and maturation to the juvenile or adult stage was estimated to take 4–10 years, with some animals possibly requiring more time. American Brook Lampreys Lethenteron appendix grew 0.13 mm/d or 0.0055 g/d on average, whereas the growth of Sea Lampreys Petromyzon marinus was variable, with ammocoetes experiencing significantly higher mean growth at one site (0.12 mm/d; 0.0025 g/d) than at the other site (0.032 mm/d; 0.00039 g/d). These estimates provide support for the generally long growth periods of ammocoetes but also suggest that variability plays a wider role even within populations. The variability in growth rate may provide ammocoetes with a highly flexible life history, allowing them to exploit habitats under a variety of conditions potentially encountered during development.Received June 16, 2016; accepted October 12, 2016 Published online December 12, 2016

Bait preference for remote camera trap studies of the endangered northern quoll (Dasyurus hallucatus)

Estimating population size is crucial for managing populations of threatened species. In the Top End of northern Australia, populations of northern quolls (Dasyurus hallucatus), already affected by livestock grazing, inappropriate burning regimes and predation, have collapsed following the spread of the toxic cane toad (Rhinella marina). Cane toads are currently invading the Kimberley, where they pose a threat to quoll populations. To manage these populations, we need reliable methods for detecting and estimating quoll abundance. We deployed camera traps with lures containing tuna, peanut butter or no bait and found that baited cameras performed better than the unbaited control. Cameras with a tuna lure detected more individuals than cameras baited with peanut butter or no bait. Cameras with a tuna lure yielded more photographs per quoll than those baited with peanut butter or no bait. We identified individual quolls from unique spot patterns and found multiple photographs improved the accuracy of identification. We also found that population estimates for the sample area derived from camera trapping were consistent with those from live trapping using mark–recapture techniques.

Female Colour Polymorphism and Unique Reproductive Behaviour in Polythore Damselflies (Zygoptera: Polythoridae).

We studied Polythore damselflies by mark-recapture techniques in the Jatun Sacha Biological Reserve (Ecuador) for a period of 48days in October-December 2014. Three species were found: Polythore mutata (MacLachlan) was the commonest species (111 individuals marked), Polythore derivata (MacLachlan) was rare (24 individuals) and Polythore concinna (MacLachlan) occasional (four individuals). In P. mutata, we found two phenotypes amongst females, one of them with a white band on the wings, very similar in colouration to the conspecific male (androchrome), and the other with an amber band (gynochrome). The recapture of marked females indicates that both phenotypes are maintained since emergence to maturation and are not age-related (i.e. polymorphism). Androchromes represent 40% of females observed. The colour of the wing band showed an age-dependent change in size with opposite trends between sexes, increasing in males and decreasing in females. Males and females were observed to return to the same forest locations in different days. Courtships and ovipositions involving androchrome females were not observed. No matings were observed in any morph. In contrast, we recorded two consecutive matings of one female P. derivata. We found that Polythore males grasp the mesothorax of females during mating instead of the prothorax as in other Zygoptera. We discuss the rarity of reproductive behaviour in this genus and how female morphs might be maintained.

Measuring the Effects of Water-based Recreation on the Spatial Ecology of Eastern Musk Turtles (Sternotherus odoratus) in a Provincial Park in Ontario, Canada

Provincial and state parks are often considered to be areas that protect native flora and fauna, but parks are also used for human recreation. We assessed the impacts of human recreation on the spatial ecology and health of Sternotherus odoratus in Massasauga Provincial Park (MPP), Ontario, Canada over two field seasons. Our study site is unique in that MPP has no roads and is accessible only by air or water, thus removing the well-known detrimental effects of roads on the resident turtle populations. Using mark–recapture techniques and radio telemetry, we studied turtles in two replicated site categories: impacted and non-impacted. Impacted sites were areas with human recreational activities (e.g., camping, boating), while non-impacted sites had no designated park use and had minimal use by park visitors. We predicted that turtles would avoid humans and thus have larger home range sizes and greater movements in impacted sites. We also predicted higher mortality and injury rates caused by subsidized preda...