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Hofmeester, T. R., Cromsigt, J. P. G. M., Odden, J., Andrén, H., Kindberg, J., & Linnell, J. D. C. (2019). Framing pictures: A conceptual framework to identify and correct for biases in detection probability of camera traps enabling multi-species comparison. Ecol Evol, .
Abstract: Abstract Obtaining reliable species observations is of great importance in animal ecology and wildlife conservation. An increasing number of studies use camera traps (CTs) to study wildlife communities, and an increasing effort is made to make better use and reuse of the large amounts of data that are produced. It is in these circumstances that it becomes paramount to correct for the species- and study-specific variation in imperfect detection within CTs. We reviewed the literature and used our own experience to compile a list of factors that affect CT detection of animals. We did this within a conceptual framework of six distinct scales separating out the influences of (a) animal characteristics, (b) CT specifications, (c) CT set-up protocols, and (d) environmental variables. We identified 40 factors that can potentially influence the detection of animals by CTs at these six scales. Many of these factors were related to only a few overarching parameters. Most of the animal characteristics scale with body mass and diet type, and most environmental characteristics differ with season or latitude such that remote sensing products like NDVI could be used as a proxy index to capture this variation. Factors that influence detection at the microsite and camera scales are probably the most important in determining CT detection of animals. The type of study and specific research question will determine which factors should be corrected. Corrections can be done by directly adjusting the CT metric of interest or by using covariates in a statistical framework. Our conceptual framework can be used to design better CT studies and help when analyzing CT data. Furthermore, it provides an overview of which factors should be reported in CT studies to make them repeatable, comparable, and their data reusable. This should greatly improve the possibilities for global scale analyses of (reused) CT data.
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Griebenow, K., & Klibanov, A. M. (1995). Lyophilization-induced reversible changes in the secondary structure of proteins. Proc Natl Acad Sci USA, 92(24), 10969–10976.
Abstract: Changes in the secondary structure of some dozen different proteins upon lyophilization of their aqueous solutions have been investigated by means of Fourier-transform infrared spectroscopy in the amide III band region. Dehydration markedly (but reversibly) alters the secondary structure of all the proteins studied, as revealed by both the quantitative analysis of the second derivative spectra and the Gaussian curve fitting of the original infrared spectra. Lyophilization substantially increases the beta-sheet content and lowers the alpha-helix content of all proteins. In all but one case, proteins become more ordered upon lyophilization.
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Palme, R., Touma, C., Arias, N., Dominchin, M.N., & Lepschy, M. (2013). Steroid extraction: Get the best out of faecal samples. Wien Tierärztl Monat – Vet Med Austria, 100, 238–246.
Abstract: Faecal steroid hormone metabolites are becoming increasingly popular as parameters for reproductive functions and stress. The extraction of the steroids from the faecal matrix represents the initial step before quantification can be performed. The steroid metabolites present in the faecal matrix are of varying polarity and composition, so selection of a proper extraction procedure is essential. There have been some studies to address this complex but often neglected point. Radiolabelled steroids (e.g. cortisol or progesterone) have frequently been added to faecal samples to estimate the efficiency of the extraction procedures used. However, native, unmetabolized steroids are normally not present in the faeces and therefore the results are artifi- cial and do not accurately reflect the actual recoveries of the substances of interest. In this respect, recovery experiments based on faecal samples from radiometabolism studies are more informative. In these samples, the metabolite content accurately reflects the mixture of metabolites present in the given species. As a result, it is possible to evaluate different extraction methods for use with faecal samples. We present studies on sheep, horses, pigs, hares and dogs that utilized samples containing naturally metabolized, 14C-labelled steroids. We recommend extracting faecal steroids by simply suspending the faeces in a high percentage of a primary alcohol (for glucocorticoid metabolites 80% aqueous methanol proved best suited for virtually all mammalian species tested so far). Not only does the procedure significantly increase the total amount of recovered radioactivity, it also increases the percentage of unconjugated metabolites, which are more likely to be recognized by the antibodies used in various immunoassays. The advantages of this extraction procedure are clear: it is very easy to use (no evaporation step is needed), it yields high recoveries and variation based on the extraction procedure is reduced to a minimum.
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Gholib, G., Heistermann, M., Agil, M., Supriatna, I., Purwantara, B., Nugraha, T. P., et al. (2018). Comparison of fecal preservation and extraction methods for steroid hormone metabolite analysis in wild crested macaques. Primates, 59(3), 281–292.
Abstract: Since the non-invasive field endocrinology techniques were developed, several fecal preservation and extraction methods have been established for a variety of species. However, direct adaptation of methods from previous studies for use in crested macaques should be taken with caution. We conducted an experiment to assess the accuracy and stability of fecal estrogen metabolite (E1C) and glucocorticoid metabolite (GCM) concentrations in response to several preservation parameters: (1) time lag between sample collection and fecal preservation; (2) long-term storage of fecal samples in 80% methanol (MeOH) at ambient temperature; (3) different degrees of feces drying temperature using a conventional oven; and (4) different fecal preservation techniques (i.e., freeze-drying, oven-drying, and field-friendly extraction method) and extraction solvents (methanol, ethanol, and commercial alcohol). The study used fecal samples collected from crested macaques (Macaca nigra) living in the Tangkoko Reserve, North Sulawesi, Indonesia. Samples were assayed using validated E1C and GCM enzyme immunoassays. Concentrations of E1C and GCM in unprocessed feces stored at ambient temperature remained stable for up to 8 h of storage after which concentrations of both E1C and GCM changed significantly compared to controls extracted at time 0. Long-term storage in 80% MeOH at ambient temperature affected hormone concentrations significantly with concentrations of both E1C and GCM increasing after 6 and 4 months of storage, respectively. Drying fecal samples using a conventional oven at 50, 70, and 90 °C did not affect the E1C concentrations, but led to a significant decline for GCM concentrations in samples dried at 90 °C. Different fecal preservation techniques and extraction solvents provided similar results for both E1C and GCM concentrations. Our results confirm previous studies that prior to application of fecal hormone analysis in a new species, several preservation parameters should be evaluated for their effects on hormone metabolite stability. The results also provide several options for fecal preservation, extraction, and storage methods that can be selected depending on the condition of the field site and laboratory.
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Broekhuis, F., Madsen, E. K., & Klaassen, B. (2019). Predators and pastoralists: how anthropogenic pressures inside wildlife areas influence carnivore space use and movement behaviour. Anim Conserv, .
Abstract: Abstract Across the globe, wildlife populations and their behaviours are negatively impacted by people. Protected areas are believed to be an antidote to increasing human pressures but even they are not immune to the impact of anthropogenic activities. Areas that have been set aside for the protection of wildlife therefore warrant more attention when investigating the impact of anthropogenic pressures on wildlife. We use cheetahs Acinonyx jubatus as a case study to explore how a large carnivore responds to anthropogenic pressures inside wildlife areas. Using GPS-collar data we investigate cheetah space use, both when moving and stationary, and movement parameters (speed and turn angles) in relation to human disturbance, distance to human settlement, livestock abundance and livestock site use inside wildlife areas. Space use was negatively influenced by human disturbance, resulting in habitat loss and fragmentation and potentially reducing landscape permeability between neighbouring wildlife areas. Cheetahs were also less likely to stop in areas where livestock numbers were high, but more likely to stop in areas that were frequently used by livestock. The latter could reflect that cheetahs are attracted to livestock however, cheetahs in the study area rarely predated on livestock. It is therefore more likely that areas that are frequently used by livestock attract wild herbivores, which in turn could influence cheetah space use. We did not find any effects of people and livestock on cheetahs? speed and turn angles which might be related to the resolution of the data. We found that cheetahs are sensitive to human pressures and we believe that they could be an indicator species for other large carnivores facing similar challenges. We suggest that further research is needed to determine the levels of anthropogenic pressures needed to maintain ecological integrity, especially inside wildlife areas.
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Lee, P. (1991). Adaptation to environmental change:an evolutionary perspective. In H. O. Box (Ed.), Primate responses to environmental changes (pp. 39–56). London: Chapmann & Hall.
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Beck, B. B. (1980). Animal tool behaviour: The use and manufacture of tools by animals. New York: Garland.
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Fisher, J., & Hinde, R. A. (1994). The opening of milk bottles by birds. British Birds, (42), 347–357.
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Kuczaj, S. A., Makecha, R., Trone, M., Paulos, R. D., & Ramos, J. A. (2006). Role of Peers in Cultural Innovation and Cultural Transmission: Evidence from the Play of Dolphin Calves. Int. J. Comp. Psychol, 19(2), 223–240.
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Thorpe, W. H. (1963). Learning and Instinct in Animals. London: Methuen.
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