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BackgroundUnderstanding rhino movement behavior, especially their recursive movements, holds significant promise for enhancing rhino conservation efforts, and protecting their habitats and the biodiversity they support. Here we investigate the daily, biweekly, and seasonal recursion behavior of rhinos, to aid conservation applications and increase our foundational knowledge about these important ecosystem engineers.MethodsUsing relocation data from 59 rhinos across northern Namibia and 8 years of sampling efforts, we investigated patterns in 24-h displacement at dawn, dusk, midday, and midnight to examine movement behaviors at an intermediate scale and across daily behavioral modes of foraging and resting. To understand recursion patterns across animals' short and long-term ranges, we built T-LoCoH time use grids to estimate recursive movement by each individual. Comparing these grids to contemporaneous MODIS imagery, we investigated productivity's influence on short-term space use and recursion. Finally, we investigated patterns of recursion within a year's home range, measuring the time to return to the most intensively used patches.ResultsTwenty four-hour displacements at dawn were frequently smaller than 24-h displacements at dusk or at midday and midnight resting periods. Recursion analyses demonstrated that short-term recursion was most common in areas of median rather than maximum NDVI values. Investigated across a full year, recursion analysis showed rhinos most frequently returned to areas within 8-21 days, though visits were also seen separated by months likely suggesting seasonality in range use.ConclusionsOur results indicate that rhinos may frequently stay within the same area of their home ranges for days at a time, and possibly return to the same general area days in a row especially during morning foraging bouts. Recursion across larger time scales is also evident, and likely a contributing mechanism for maintaining open landscapes and browsing lawns of the savanna.

Olfactory lures are important pest control tools, being widely used to attract animals to detection devices, traps, and poisons. For small mammals, like commensal rodents, almost all lures are foods. For invertebrates, however, semiochemical lures predominate and have done so for decades. Semiochemical lures overcome the inherent limitations of food-based lures, such as their perishability and inconsistent odour properties, and poor performance when foods are abundant. They can also provide benefits like low cost, ease of handling, and in-field longevity. Semiochemical lures for rodents would be a major advance, like that achieved for invertebrate monitoring and control, but their discovery has been constrained by the complexity of the challenge. Our research group is the first to achieve animal response-guided semiochemical lure discovery. We statistically integrated rapid field-based bioassays with scent chemical profiling and partial least squares regression to identify and test a suite of new single- and multi-compound rat lures. Field trials identified a tetrad and dyad mixture as the best performing lures, with an attraction rate of 0.61 and 0.60, respectively, compared to an attraction rate of 0.55 for the peanut butter standard. In total, 17 compound-based lures performed statistically as well as the peanut butter standard. We are currently working with an industry partner to encapsulate the lures as consumable, cost-effective pest-control products. Semiochemical lures will be particularly useful for multi-kill traps, toxic bait delivery devices, and remote monitoring devices that could operate for long periods without intervention. These devices offer substantial control program cost reductions but require long-life lures to realise their full potential.

Olfactory lures are important tools in pest-species management, being widely used to monitor and trap populations. For vertebrates like rats, lures are most commonly foods such as peanut butter. However, these are perishable and require frequent replenishment; factors that decrease control operation efficacy and increase costs. Synthetic semiochemical-based lures might address these limitations, but their identification and use for vertebrate population management remains an underexploited opportunity. We used headspace solid-phase microextraction and gas chromatography-mass spectrometry to characterise the volatile chemical profiles of 19 food products previously presented to wild, free-ranging rats and assessed for attraction. Partial least squares regression identified 10 of the 111 compounds found in two or more analysed products to be statistically significant predictors of attraction. The identity of nine of the compounds was verified using authentic samples, while one was not commercially available. Field trials used tracking tunnels to present compounds at seven different concentrations from 10,000 ppm to 0.01 ppm. Inked cards inside tracking tunnels were used to quantify visitations using species tracking marks, with the presence of rat tracks on inked cards scored to provide a tracking rate. Five compounds outperformed peanut butter while eight individual semiochemical-based lures each statistically outperformed peanut butter. Nearly half of all confirmed visits to compounds were with lures presented at 0.1 and 0.01 ppm. A trend of increasing tracking rates with decreasing lure concentration was identified for aggregated compound data. Our results suggest a number of compounds have the potential for onward development as synthetic attractants for rats. Further, the results support our integrated chemical image and response-guided approach that statistically associated behavioural responses to a range of products with the volatile compounds in those products. This approach has the potential to identify semiochemical compounds, either allelochemical or pheromone, for use as olfactory lures for managing and monitoring a range of vertebrate pest species.

The article discusses the issue of invasive species denialism and the accusations that have been made against scientists and practitioners in the field of invasion biology. The authors argue that these accusations lack evidence and rigor, and that they are leading to unscientific discourse and a decline in public trust in science. They also highlight the potential negative consequences for those accused of denialism, including damage to their reputation and employment opportunities. The authors call for a more considered and circumspect approach to accusations of invasive species denialism, aligning scientific work with the values of cooperation, open-mindedness, evidence, and honesty. [Extracted from the article]

Wildlife-based tourism poses opportunities and challenges for species conservation. Minimizing potential negative impacts of tourism is critical to ensure business and conservation enterprises can coexist. In north-western Namibia tourism is used as a conservation tool for the Critically Endangered black rhinoceros Diceros bicornis. However, black rhinoceroses are susceptible to human disturbance and may become displaced by tourist activities, which threatens not only the security and health of the rhinoceros population but also the sustainability of the business. We examined areas avoided by black rhinoceroses to understand how they respond to the type and extent of tourism development, and to evaluate management alternatives. We used spatial data on use of water sources by rhinoceroses to create a series of a priori candidate models that described the negative influences of tourist activities on rhinoceros habitat use. A model selection approach strongly supported a cumulative zones of influence model comprised of a 6 km buffer around the airstrip combined with a 1 km buffer around roads used daily. We compared alternative management scenarios using the best-performing model and found that an optimal road-use policy combined with airstrip relocation could minimize the total area avoided by the black rhinoceros to 7.1% and loss of high quality habitat to 20.7%. Under the worst-case scenario the area avoided and loss of high quality habitat were 153 and 85% greater, respectively, than under the scenario with optimal management. Our findings provide a novel framework and a practical, policy-relevant decision support tool to improve the contribution of tourism to wildlife conservation. [ABSTRACT FROM AUTHOR]

Pro-environmental behaviors (PEBs) may be associated with a personal relationship with nature. We conducted a quasi-experiment with 423 residents who had or had not actively participated in a tree-planting scheme and lived in 20 neighborhoods that differ in their greenness level. We tested whether exposure to nature (specified by the amount of vegetation cover in residents' neighborhoods) and/or past PEB (specified by tree-planting participation) was associated with residents' PEB and whether key psychological constructs would mediate these relationships. Structural equation mediation models revealed that the level of neighborhood vegetation and involvement in the planting scheme explained 46% of the variance in PEB, with connection to nature, the use of nature for psychological restoration, and environmental attitudes mediating the relationships. Connection to nature was more strongly associated with engagement in PEB than the use of nature for psychological restoration and environmental attitudes. [ABSTRACT FROM AUTHOR]

Remnant forest fragments are critical to conserve biological diversity yet these are lost rapidly in areas under agricultural expansion. Conservation planning and policy require a deeper understanding of the psycho-social factors influencing landholders' intentions towards conserving forest fragments. We surveyed 89 landholders in an agricultural frontier of the South American Gran Chaco and employed survey data to test three social psychological models: the Theory of Planned Behavior (TPB) and two modified versions of it, one integrated to the Norm Activation Theory (TPB-NAT) and one including the effect of identity (TPB-NAT-Identity). The TPB was the most parsimonious model and explained a large variance of conservation intentions (41%). Social norms and attitudes had the largest direct influence on intentions across the three models, and identity had a significant role in shaping social norms and attitudes. Interventions aimed at building social capital within landholder networks provide the best hope for influencing pro-conservation norms. [ABSTRACT FROM AUTHOR]

The North Island kākā (Nestor meridionalis septentrionalis), a threatened New Zealand native parrot, was successfully reintroduced to an urban sanctuary in Wellington, New Zealand. Conflict has recently begun to emerge with Wellington City residents due to tree damage caused by kākā sap foraging. Little is known about sap foraging behavior of kākā, and this study aimed to gain a greater understanding of this behavior, and to test hypotheses that sap feeding is predominantly a female activity and that one technique, forming transverse gouges through bark, may be restricted to adult kākā. We used instantaneous scan sampling to record the behavior of kākā during 25 60--100 minute observation periods at Anderson Park, Wellington Botanic Garden, and during 13 opportunistic observations of sap feeding kākā in Wellington City. Forty-one observations of sap feeding were made of 21 individually-identified birds. Sap feeding birds were predominantly young and, based on estimated sex, females were no more likely to sap feed than males (exact binomial test p = 0.868). Twenty of the 21 identified sap feeding kākā utilized supplementary feeding stations at Zealandia-Karori Wildlife Sanctuary. Kākā were observed defending sap feeding sites from tui (Prosthemadera novaeseelandiae) and conspecifics. Sap appears to be an important resource for kākā across sexes and life stages, and provision of supplementary food is unlikely to reduce sap feeding and tree damage in Wellington City. [ABSTRACT FROM AUTHOR]

Several hypotheses have been proposed to explain variation in birth sex ratios, based on the premise that variation is expected when the profitability of raising sons and daughters varies between individualparents. We tested the Trivers-Willard hypothesis that mothers in better condition produce relatively more sons and that mothers in poorer condition produce relatively more daughters when male reproductive success is more variable. We examined birth sex ratios in relation tomare body condition at conception in horses in which male reproductive success is differentially helped by slight advantages in condition. Horses meet the assumptions of the Trivers-Willard hypothesis better than many species on which it has been tested and in which sex ratio biases are not confounded by sexual size dimorphism such that one sex is more likely to die in utero in females in poor condition. Maresthat had a female foal were in poorer condition at conception than those that had a male foal, and mares that had foals of different sexes in different years were in significantly poorer condition when theyconceived their female foal. There was no relationship between offspring sex and mid-gestation condition, and there was no difference in foaling rates in relation to body condition at conception. Consequently, sex ratio deviations are not explained by fetal loss in utero. Furthermore, differential fetal loss of the less viable sex cannot explain the greater proportion of males produced by mares in better condition. Therefore, our results suggest that sex ratio modification occurs at conception in wild horses. [ABSTRACT FROM AUTHOR]

Faecal egg counts (FECs) are commonly used for the non-invasive assessment of parasite load within hosts. Sources of error, however, have been identified in laboratory techniques and sample storage. Here we focus on sampling error. We test whether a delay in sample collection can affect FECs, and estimate the number of samples needed to reliably assess mean parasite abundance within a host population. Two commonly found parasite eggs in black rhinoceros (Diceros bicornis) dung, strongyle-type nematodes and Anoplocephala gigantea, were used. We find that collection of dung from the centre of faecal boluses up to six hours after defecation does not affect FECs. More than nine samples were needed to greatly improve confidence intervals of the estimated mean parasite abundance within a host population. These results should improve the cost-effectiveness and efficiency of sampling regimes, and support the usefulness of FECs when used for the non-invasive assessment of parasite abundance in black rhinoceros populations.