Urinary steroid evaluations to monitor ovarian function in exotic ungulates: VI. Pregnancy detection in exotic equidae

The measurement of serum and urinary estrone sulfate (ES) was evaluated on random single samples for the detection of pregnancy in the Przewalski's horse (PRZ) and Hartmann's mountain zebra (HMZ). Pregnancy was detected by ES analysis of urine or serum in the PRZ and HMZ by at least 8 and 10 months before delivery, respectively. The values of ES in both serum and urine are shown at various stages of gestation. Results indicate urinary ES analysis is a noninvasive early diagnosis for pregnancy in these species.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: X. Pregnancy diagnosis in Perissodactyla

Enzymeimmunoassays (EIAs) for estrone conjugates (EC), pregnanediol-3-glucuronide (PDG), and C-19 and C-21 progesterone metabolites (C-19/C-21) were used to analyze urine samples from four nondomestic equid species, four tapir species, and two rhinoceros species in an attempt to identify if these assays could be used for diagnosing and monitoring pregnancy. The same urine samples were also analyzed for the presence of equine chorionic gonadotropin (eCG) activity, using a field dipstick test and a radioimmunoassay (RIA). The EC EIA was validated for three equid species and the Malayan tapir. Neither the PDG nor the C-19/C-21 EIAs were validated in any species evaluated. In equid species, the EC EIA demonstrated a specificity (the percentage of nonpregnant samples identified correctly) of 100% and a sensitivity (the percentage of pregnant samples identified correctly) of ≥ 88%. With the exception of the Grevy's zebra, the C-19/C-21 EIA showed a similar accuracy in identifying pregnant and nonpregnant equids. The PDG EIA was not sufficiently accurate to merit its use in equids or tapirs for pregnancy diagnosis. From the data collected, it appears analysis of a single urine by both the EC EIA and the C-19/C-21 EIA would be the best method of pregnancy detection during the last 2 trimesters of gestation, in equid species. In tapirs, the C-19/C-21 EIA was slightly more accurate for pregnancy diagnosis than the EC EIA. The C-19/C-21 EIA had a specificity of 93%, but a sensitivity of only 73% in tapir species. None of the EIAs evaluated demonstrated a sufficient specificity or sensitivity to be useful, as presently performed, for pregnancy diagnosis from a single sample in the black rhinoceros. The eCG dipstick used in this study did not prove a sufficiently reliable test for routine pregnancy in nondomestic equids. The eCG RIA results in the Przewalski's horses and the Hartman's mountain zebra were positive early in gestation, and indicate that gonadotropin analysis may be useful for pregnancy detection in these species. Only very low amounts of eCG activity was measured by the eCG RIA in the tapir and rhinoceros urine samples. © 1994 Wiley-Liss, Inc.     

Identifying and correcting spatial bias in opportunistic citizen science data for wild ungulates in Norway

Many publications make use of opportunistic data, such as citizen science observation data, to infer large‐scale properties of species’ distributions. However, the few publications that use opportunistic citizen science data to study animal ecology at a habitat level do so without accounting for spatial biases in opportunistic records or using methods that are difficult to generalize. In this study, we explore the biases that exist in opportunistic observations and suggest an approach to correct for them. We first examined the extent of the biases in opportunistic citizen science observations of three wild ungulate species in Norway by comparing them to data from GPS telemetry. We then quantified the extent of the biases by specifying a model of the biases. From the bias model, we sampled available locations within the species’ home range. Along with opportunistic observations, we used the corrected availability locations to estimate a resource selection function (RSF). We tested this method with simulations and empirical datasets for the three species. We compared the results of our correction method to RSFs obtained using opportunistic observations without correction and to RSFs using GPS‐telemetry data. Finally, we compared habitat suitability maps obtained using each of these models. Opportunistic observations are more affected by human access and visibility than locations derived from GPS telemetry. This has consequences for drawing inferences about species’ ecology. Models naïvely using opportunistic observations in habitat‐use studies can result in spurious inferences. However, sampling availability locations based on the spatial biases in opportunistic data improves the estimation of the species’ RSFs and predicted habitat suitability maps in some cases. This study highlights the challenges and opportunities of using opportunistic observations in habitat‐use studies. While our method is not foolproof it is a first step toward unlocking the potential of opportunistic citizen science data for habitat‐use studies.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: IV. Estrogen metabolism in the okapi (Okapia johnstoni)

In this investigation, an attempt was made to identify the major urinary estrogen metabolites in the okapi by radioisotope infusion and by chromatographic separation procedures. The results suggest that the urinary estrogens are excreted in concentrations below the limit of sensitivity of conventional assay systems. In addition, a variety of contaminants with estrogenic immunoreactivity are present in okapi urine that are not necessarily correlated with follicular activity. A great proportion of circulating estrogen is eliminated in fecal material. However, the rate of elimination is slow, and the extraction procedures necessary to detect the metabolites are tedious, which would prevent the practical application of this procedure for monitoring follicular activity.     

How to work with children and animals: A guide for school‐based citizen science in wildlife research

Engaging school students in wildlife research through citizen science projects can be a win–win for scientists and educators. Not only does it provide a way for scientists to gather new data, but it can also contribute to science education and help younger generations become more environmentally aware. However, wildlife research can be challenging in the best of circumstances, and there are few guidelines available to help scientists create successful citizen science projects for school students. This paper explores the opportunities and challenges faced when developing school‐based citizen science projects in wildlife research by synthesising two sources of information. First, we conducted a small, school‐based citizen science project that investigated the effects of supplementary feeding on urban birds as a case study. Second, we reviewed the literature to develop a database of school‐based citizen science projects that address questions in wildlife ecology and conservation. Based on these activities, we present five lessons for scientists considering a school‐based citizen science project. Overall, we found that school‐based citizen science projects must be carefully designed to ensure reliable data are collected, students remain engaged, and the project is achievable under the logistical constraints presented by conducting wildlife research in a school environment. Ultimately, we conclude that school‐based citizen science projects can be a powerful way of collecting wildlife data while also contributing to the education and development of environmentally aware students.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: VII. Urinary progesterone metabolites in the Equidae assessed by immunoassay

A direct enzyme immunoassay (EIA) for non-specific urinary progesterone (Po) metabolites, utilizing a non-specific monoclonal antibody against pregnanediol-3-glucuronide, was evaluated for the purpose of assessing luteal function in equids. Urinary pregnanediol-3-glucuronide (PdG) and immunoreactive PdG-like conjugate (iPdG) concentrations, indexed by creatinine, were compared to plasma Po concentrations in non-conceptive ovarian cycles through two ovulations in four mares. High-performance liquid chromatography (HPLC) of urine from lutealphase mares and a pregnant zebra revealed an absence of significant concentrations of PdG and the presence of at least three immunoreactive compounds, all of which were more polar than PdG. The concentration of iPdG in the mare ranged from a nadir of approximately 3 ng/mg Cr at the time of ovulation to nearly 400 ng/mg Cr at the mid-luteal-phase peak and paralleled plasma Po concentrations. This non-radiometric assay for iPdG permits the assessment of ovulation, luteal formation and function, and luteolysis in unprocessed urine samples from domestic mares. Data from a single zebra indicate this approach also will permit simplified and non-invasive longitudinal studies of ovarian function among a wide range of Equidae.     

Ecological and anthropogenic effects on the density of migratory and resident ungulates in a human‐inhabited protected area

Understanding the influence of environmental conditions and people on ungulate density and distribution is of key importance for conservation. We evaluated the effects of ecological and anthropogenic factors on the density of migratory wildebeest and zebra and resident oribi in Zambia's Liuwa Plain National Park where human settlements were present. We conducted transect surveys from 2010 to 2013 using distance sampling methods and then developed a set of 38 candidate models to describe results and predict density. Models included the effects of variables in three classes: environmental (year, season, vegetation, predominant grass height, burn, water presence), predation risk (hyaena density) and anthropogenic (distance to park boundary and settlements). Densities ranged from 6.2 to 60.8 individuals km^?2 for wildebeest, 1.1 to 14.5 individuals km^?2 for oribi and 1.8 to 8.1 individuals km^?2 for zebra. The most complex models were strongly supported for all three species. The magnitude and sign of variable effects differed among species, indicating that local densities of wildebeest, oribi and zebra are affected by a complex set of anthropogenic and ecological factors. Results reveal resource partitioning among ungulate species and indicate that predation risk and proximity to humans affect ungulate distributions with implications for managing migrations in the Greater Liuwa Ecosystem.     

Conservation implications of native and introduced ungulates in a changing climate

In many grasslands, grazing by large native or introduced ungulates drives ecosystem structure and function. The behavior of these animals is important as it directs the spatial effects of grazing. To the degree that temperature drives spatial components of foraging, understanding how changes in climate alter grazing behavior will provide guidance for the conservation of ecosystem goods and services. We determined the behavioral response of native bison (Bison bison) and introduced cattle (Bos taurus) to temperature in tallgrass prairie within the Great Plains, USA. We described the thermal environment by measuring operative temperature (the temperature perceived by animals) through space and time. Site selection preferences of ungulates were quantified using resource selection functions. Woody vegetation in tallgrass prairie provided a cooler thermal environment for large ungulates, decreasing operative temperature up to 16 °C in the heat of the summer. Cattle began to seek thermal refugia at lower air temperatures (24 °C) by selecting areas closer to woody vegetation and water sources. Bison, however, sought refugia within wooded areas at higher air temperatures (36 °C), which occurred much less frequently. Both species became more attracted to riparian areas as air temperature increased, with preferences increasing tenfold during the hottest periods. As predicted warming occurs across the Great Plains and other grasslands, grazing behavior and subsequent grazing effects will be altered. Riparian areas, particularly those with both water and woody vegetation, will receive greater utilization and selection by large ungulates. The use of native grazers for conservation or livestock production may mitigate negative effects caused by increased temperatures.     

Using citizen science to monitor Bombus populations in the UK: nesting ecology and relative abundance in the urban environment

Citizen science can provide a valuable tool for collecting large quantities of ecological data over a larger geographic area than would otherwise be possible. Here, data were collected on 1,022 bumblebee nests by means of a public survey in which participants were asked to record attributes of bumblebee nests discovered in their gardens. All commonly reported species appeared to be generalist in their nest site selection and though species-specific differences in nest site choice were evident, there was a high degree of overlap in nesting habitat between most species. There was little evidence supporting the hypothesis that bumblebees tend to nest in the same site in consecutive years. A comparison of the contributions made by different species to the total nests reported in this and previous similar surveys suggests that the common bumblebee species Bombus pascuorum may have declined over the past 20?years relative to other species, comprising ~21% of colonies discovered in a survey conducted in 1989–1991, but just 8–9% of colonies in 2007–2009. This was accompanied by a reduction in the proportion of nests on the ground surface (the preferred position of this species). This is the first quantitative evidence of potential declines in the one of the UK’s ‘big six’ common bumblebee species.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: I. Pregnanediol-3-glucuronide immunoreactivity in the okapi (Okapia johnstoni)

Immunoreactive pregnanediol-3-glucuronide was assessed in daily urine samples from five female okapis. Indexed by creatinine (CR), the resultant profiles accurately reflect ovulation and pregnancy in this species. The infertile cycle was approximately 14.5 days by this method with the preovulatory levels averaging less than 1 ng/mg CR (N = 88) for approximately eight days (N = 28). Postovulatory levels averaged 24 ng/mg CR (N = 55) in one female and 12 ng/mg CR (N = 27) in another for approximately six days (N = 26). Pregnancy is confidently detected by three weeks postcoition by elevated pregnanediol levels that remain significantly higher that luteal phase levels until weeks before parturition.     

Interactions of exotic and native carnivores in an ecotone, the coast of the Beagle Channel, Argentina

In coasts bordering highly productive seas, there can be a flux of resources to the terrestrial ecosystem, and terrestrial carnivores can use marine prey extensively. Two native, endangered species (otter Lontra provocax and culpeo fox Pseudalopex culpaeus lycoides) and two exotic species (mink Neovison vison and grey fox Pseudalopex griseus) inhabit the Beagle coast. The objectives of this paper are: (1) to describe the diet, habitat use and distribution of otters, mink and foxes on the coast of the Beagle channel and (2) to discuss the role of marine resources in the ecological interactions among these species. Diet was determined from the analysis of 245 faeces, and distribution was established from sign surveys. Marine prey occurred in the scats of 98.3, 70.4, 35.5 and 18.2% of otters, mink, culpeo and grey foxes, respectively. Other terrestrial species also use marine resources in Southern Patagonia. All this evidence suggests that the Fueguian coastal channels provide an illuminating example of allochthonous food subsidies from the sea. In the community of four sympatric predators, two native (and endangered) and two exotic, coexistence appears to be facilitated by a renewing marine food subsidy.     

Survival and growth of native and exotic composites in response to a nutrient gradient

Mortality and performance (total biomass) of five exotic (weedy) and five native annual Asteraceae in Western Australia were compared along a mineral nutrient gradient. Mortality did not differ between exotic and native species but varied greatly within each group. The exotic species responded more positively to higher nutrient additions than the native species, indicating that the exotics might have a competitive advantage in a nutrient-enhanced situation (e.g., after fire). The concept of phenotypic inertia (PI), combining survival and performance over a range of environments, is introduced as a means of evaluating the range of growing conditions tolerated. The two species with highest PI (one exotic and one native) had the lowest mortality and uniformly moderate biomass for the nine nutrient treatments. The species with the lowest PI (a native) had complete failure at the two highest nutrient levels and low variable growth in the remainder. PI has potential as a measure of environmental tolerance although, in the present study, the exotic species were not clearly superior to the native species in their responses to a wide range of soil nutrient levels.     

Interactive effects of insects and ungulates on root growth in a native grassland

Insects and ungulates co‐occur in grasslands, often feeding on the same plants at the same time and potentially having interactive effects on plant growth. Further, ungulate–insect interactions may differ between native ungulate guilds and domesticated cattle. Despite the prevalence of insects and ungulates in native grasslands, experiments simultaneously manipulating the densities of both these groups are rare. Using large, replicated paddocks, as well as insecticide application, we restricted access to vegetation by each group of herbivores. We also manipulated the species identity of the ungulate assemblage, allowing us to determine whether there are differential effects between native ungulate guilds (bison, elk and deer) and cattle on plant biomass. We found interactive effects of insect and ungulate herbivores on root growth. When insects were suppressed, both native ungulates and cattle caused an approximate doubling of root biomass. However, this stimulatory effect of ungulate grazing was eliminated when insects were also present. In contrast, neither insects nor ungulates had significant effects on shoot biomass at these densities. As a result, the dominant effects of above‐ground herbivory was on belowground plant growth. We suggest the effects of insect and ungulate assemblages on root biomass appear important in regulating primary production in this grassland and may account for some of the contradictory plant responses to ungulate herbivory in the literature.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: V. Estrogen and pregnanediol-3-glucuronide excretion in the black rhinoceros (Diceros bicornis)

A study of female black rhinoceros (Diceros bicomis) urinary steroid and steroid metabolite excretion was performed to determine if techniques useful for monitoring reproductive events in the Indian rhinoceros (Rhinoceros unicornis) could be utilized to evaluate the black rhinoceros. Urine samples from 19 zoo-held black rhinoceros were analyzed for estrogen, estrone conjugates (EC), and pregnanediol-3-glucuronide (PDG) content by direct radioimmunoassays. Estrogen analysis revealed that >95% of the estrogens present in female black rhinoceros urine are conjugated, with estrone and estradiol accounting for virtually all of these estrogens. There is no observable difference in the amount of estrogen present in estrus; postestrus; and early-, mid-, and late-gestation urine samples. Analysis of serial urine samples for EC failed to reveal any discernible levels or patterns which reflected reproductive status. Neither nonpregnant nor early-gestational female black rhinoceros' urine samples contained detectable amounts of PDG. Urinary PDG concentrations became measurable in midgestation (9–12 months prior to parturition) and rose steadily throughout the remainder of gestation. PDG levels declined sharply and became nondetectable 1 day postpartum. Though a wide range in PDG levels was observed among individual pregnant animals, each female consistently excreted increasing amounts of PDG through latter pregnancy.     

Differential long-term impacts of a management control program of axis deer and wild boar in a protected area of north-eastern Argentina

Exotic ungulates are among the top global invasive mammals and a threat to biodiversity. Axis deer (Axis axis) and wild boar (Sus scrofa) are of increasing concern in multiple regions. A management program reduced wild boar abundance and soil damage below target levels through controlled still shooting from watchtowers and dog-hunting performed by recreational hunters at El Palmar National Park, Argentina. Here we assess program impacts on axis deer over a 10-year period in which 2380 deer were dispatched, and document two largely unexpected outcomes: increasing axis deer abundance toward a plateau, and a strong inverse correlation between deer and wild boar numbers. Unlike the initial steep decline and subsequent stabilization of wild boar, deer abundance indexed by standardized catch-per-unit-effort increased at 37.6% per year over 0–5 years post-intervention (YPI) and stabilized from 7 YPI on when still-shooting effort averaged 948 hunting party-hours per quarter. Deer catch was non-linearly related to still-shooting effort. Timing of deer and boar catches did not differ significantly regardless of sex, season and YPI. Catch-per-unit-effort indices and nightly spotlight deer counts showed similarly increasing trends. The fraction of older adult deer declined over 0–4 YPI and remained stable thereafter. Sex ratios were consistently skewed toward males only among older adults. Failure to reduce deer abundance may be explained by several major processes: protracted exponential growth of the deer population after park invasion; deer regional expansion with increasing immigration; insufficient sex- and stage-biased hunting mortality, and competitor (and perhaps predator) release from wild boar.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: III. Estrone sulfate and pregnanediol-3-glucuronide excretion in the Indian rhinoceros (Rhinoceros unicornis)

A study was undertaken to identify urinary estrogen and progesterone metabolites in the female Indian rhinoceros (Rhinoceros unicornis). Measurements of these metabolites were then used to monitor ovarian function and establish normal levels and patterns of steroid excretion during the estrous cycle and pregnancy. Urine samples were analyzed for estrone sulfate and pregnanediol-3-glucuronide (PDG) by direct radioimmunoassays. Both hormones produced discrete profiles reflecting ovarian activity in nonconceptive cycles. The estrous cycle was observed to be 48 days (range 39–64) with a mean follicular phase of 14.8 days (range 13–19), followed by a mean luteal phase of 19 days (range 17–21). Of the single gestation monitored, PDG levels rose above luteal phase levels by the third month after breeding and remained elevated throughout gestation. The combined estrogen and progesterone metabolite profiles present a complete evaluation of ovarian steriod production in the mature female Indian rhinoceros.