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Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Physiological stress response of African elephants to wildlife tourism in Madikwe Game Reserve, South Africa

Isabelle D. Szott https://orcid.org/0000-0002-7872-5066 A E , Yolanda Pretorius B , Andre Ganswindt C D and Nicola F. Koyama A
+ Author Affiliations
- Author Affiliations

A School of Natural Sciences and Psychology, Byrom Street, Liverpool John Moores University, L3 3AF, Liverpool, UK.

B Centre for Wildlife Management, cnr Lynnwood Road and Roaper Street, University of Pretoria, Hatfield, Pretoria 0028, South Africa.

C Mammal Research Institute, cnr Lynnwood Road and Roaper Street, University of Pretoria, Hatfield, Pretoria 0028, South Africa.

D Endocrine Research Laboratory, Department of Anatomy and Physiology, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.

E Corresponding author. Email: I.Szott@2011.ljmu.ac.uk

Wildlife Research 47(1) 34-43 https://doi.org/10.1071/WR19045
Submitted: 7 March 2019  Accepted: 17 August 2019   Published: 23 December 2019

Abstract

Context: Wildlife tourism has been shown to increase stress in a variety of species and can negatively affect survival, reproduction, welfare, and behaviour of individuals. In African elephants, Loxodonta africana, increased physiological stress has been linked to use of refugia, rapid movement through corridors, and heightened aggression towards humans. However, we are unaware of any studies assessing the impact of tourism pressure (tourist numbers) on physiological stress in elephants.

Aims: We used faecal glucocorticoid metabolite (fGCM) concentrations to investigate whether tourist numbers in Madikwe Game Reserve, South Africa, were related to changes in physiological stress in elephants.

Methods: We repeatedly collected dung samples (n = 43) from 13 individually identified elephants over 15 months. Using a generalised linear mixed model and a Kenward–Roger approximation, we assessed the impact of monthly tourist numbers, season, age, and sex on elephant fGCM concentrations.

Key results: High tourist numbers were significantly related to elevated fGCM concentrations. Overall, fGCM concentrations increased by 112% (from 0.26 to 0.55 µg g−1 dry weight) in the months with the highest tourist pressure, compared to months with the lowest tourist pressure.

Conclusions: Managers of fenced reserves should consider providing potential alleviation measures for elephants during high tourist pressure, for example, by ensuring that refuge areas are available. This may be of even higher importance if elephant populations have had traumatic experiences with humans in the past, such as poaching or translocation. Such management action will improve elephant welfare and increase tourist safety.

Implications: Although tourism can generate substantial revenue to support conservation action, careful monitoring of its impact on wildlife is required to manage potential negative effects.

Additional keywords: conservation, faeces, physiology, stress endocrinology, welfare, wildlife management.


References

Ahlering, M. A., Madonaldo, J. E., Eggert, L. S., Fleischer, R. C., Western, D., and Brown, J. L. (2013). Conservation outside protected areas and the effect of human-dominated landscapes on stress hormones in savannah elephants. Conservation Biology 27, 569–575.
Conservation outside protected areas and the effect of human-dominated landscapes on stress hormones in savannah elephants.Crossref | GoogleScholarGoogle Scholar | 23692020PubMed |

Arnau, J., Bendayan, R., Blanca, M. J., and Bono, R. (2014). Should we rely on the Kenward–Roger approximation when using linear mixed models if the groups have different distributions? British Journal of Mathematical & Statistical Psychology 67, 408–429.
Should we rely on the Kenward–Roger approximation when using linear mixed models if the groups have different distributions?Crossref | GoogleScholarGoogle Scholar |

Behie, A. M., Pavelka, M. S. M., and Chapman, C. A. (2010). Sources of variation in fecal cortisol levels in Howler monkeys in Belize. American Journal of Primatology 72, 600–606.
Sources of variation in fecal cortisol levels in Howler monkeys in Belize.Crossref | GoogleScholarGoogle Scholar | 20166191PubMed |

Bhattacharjee, S., Kumar, V., Chandrasekhar, M., Malviya, M., Ganswindt, A., Ramesh, K., Sankar, K., and Umapathy, G. (2015). Glucocorticoid stress responses of reintroduced tigers in relation to anthropogenic disturbance in Sariska Tiger Reserve in India. PLoS One 10, e0127626.
Glucocorticoid stress responses of reintroduced tigers in relation to anthropogenic disturbance in Sariska Tiger Reserve in India.Crossref | GoogleScholarGoogle Scholar | 26061171PubMed |

Bradshaw, G. A., Schore, A. N., Brown, J. L., Poole, J. H., and Moss, C. J. (2005). Elephant breakdown. Nature 433, 807.
Elephant breakdown.Crossref | GoogleScholarGoogle Scholar | 15729320PubMed |

Burke, T., Page, B., Van Dyk, G., Millspaugh, J., and Slotow, R. (2008). Risk and ethical concerns of hunting male elephant: behavioural and physiological assays of the remaining elephants. PLoS One 3, e2417.
Risk and ethical concerns of hunting male elephant: behavioural and physiological assays of the remaining elephants.Crossref | GoogleScholarGoogle Scholar | 18560517PubMed |

Chase, M. J., Schlossberg, S., Griffin, C. R., Bouché, P. J. C., Djene, S. W., Elkan, P. W., Ferreira, S., Grossman, F., Kohi, E. M., Landen, K., Omondi, P., Peltier, A., Selier, S. A. J., and Sutcliffe, R. (2016). Continent-wide survey reveals massive decline in African savannah elephants. PeerJ 4, e2354.
Continent-wide survey reveals massive decline in African savannah elephants.Crossref | GoogleScholarGoogle Scholar | 27635327PubMed |

Creel, S., Fox, J. E., Hardy, A., Sands, J., Garrott, B., and Peterson, R. O. (2002). Snowmobile activity and glucocorticoid stress responses in wolves and elk. Conservation Biology 16, 809–814.
Snowmobile activity and glucocorticoid stress responses in wolves and elk.Crossref | GoogleScholarGoogle Scholar |

Davis, R., and Brett, M. (Ed.) (2003). ‘Madikwe Game Reserve: a Decade of Progress’. North West Parks & Tourism Board elephantvoices.org (2018). Multimedia Resources. Available at https://elephantvoices.org/multimedia-resources.html [verified 22 January 2018].

Fieß, M., Heistermann, M., and Hodges, J. K. (1999). Patterns of urinary and fecal steroid excretion during the ovarian cycle and pregnancy in the African elephant (Loxodonta africana). General and Comparative Endocrinology 115, 76–89.
Patterns of urinary and fecal steroid excretion during the ovarian cycle and pregnancy in the African elephant (Loxodonta africana).Crossref | GoogleScholarGoogle Scholar | 10375466PubMed |

Foley, C. A. H., Papageorge, S., and Wasser, S. K. (2001). Noninvasive stress and reproductive measures of social and ecological pressures in free‐ranging African elephants. Conservation Biology 15, 1134–1142.
Noninvasive stress and reproductive measures of social and ecological pressures in free‐ranging African elephants.Crossref | GoogleScholarGoogle Scholar |

Fox, J. (2003). Effect displays in R for generalised linear models. Journal of Statistical Software 8, 1–27.
Effect displays in R for generalised linear models.Crossref | GoogleScholarGoogle Scholar |

Fox, J., and Monette, G. (1992). Generalized collinearity diagnostics. Journal of the American Statistical Association 87, 178–183.
Generalized collinearity diagnostics.Crossref | GoogleScholarGoogle Scholar |

Fox, J., and Weisberg, S. (2011). ‘Multivariate Linear Models in R. An R Companion to Applied Regression.’ (SAGE Publishing: Thousand Oaks, CA, USA.)

Ganswindt, A., Palme, R., Heistermann, M., Borragan, S., and Hodges, J. (2003). Non-invasive assessment of adrenocortical function in the male African elephant (Loxodonta africana) and its relation to musth. General and Comparative Endocrinology 134, 156–166.
Non-invasive assessment of adrenocortical function in the male African elephant (Loxodonta africana) and its relation to musth.Crossref | GoogleScholarGoogle Scholar | 14511986PubMed |

Ganswindt, A., Rasmussen, H. B., Heistermann, M., and Hodges, J. K. (2005). The sexually active states of free-ranging male African elephants (Loxodonta africana): Defining musth and non-musth using endocrinology, physical signals, and behavior. Hormones and Behavior 47, 83–91.
The sexually active states of free-ranging male African elephants (Loxodonta africana): Defining musth and non-musth using endocrinology, physical signals, and behavior.Crossref | GoogleScholarGoogle Scholar | 15579269PubMed |

Ganswindt, A., Münscher, S., Henley, M., Palme, R., Thompson, P., and Bertschinger, H. (2010a). Concentrations of faecal glucocorticoid metabolites in physically injured free-ranging African elephants Loxodonta africana. Wildlife Biology 16, 323–332.
Concentrations of faecal glucocorticoid metabolites in physically injured free-ranging African elephants Loxodonta africana.Crossref | GoogleScholarGoogle Scholar |

Ganswindt, A., Münscher, S., Henley, M., Henley, S., Heistermann, M., Palme, R., Thompson, P., and Bertschinger, H. (2010b). Endocrine correlates of musth and the impact of ecological and social factors in free-ranging African elephants (Loxodonta africana). Hormones and Behavior 57, 506–514.
Endocrine correlates of musth and the impact of ecological and social factors in free-ranging African elephants (Loxodonta africana).Crossref | GoogleScholarGoogle Scholar | 20188104PubMed |

Gobush, K. S., Mutayoba, B. M., and Wasser, S. K. (2008). Long-term impacts of poaching on relatedness, stress physiology, and reproductive output of adult female African elephants. Conservation Biology 22, 1590–1599.
Long-term impacts of poaching on relatedness, stress physiology, and reproductive output of adult female African elephants.Crossref | GoogleScholarGoogle Scholar | 18759771PubMed |

Hunninck, L., Ringstad, I. H., Jackson, C. R., May, R., Fossøy, F., Uiseb, K., Killian, W., Palme, R., and Røskaft, E. (2017). Being stressed outside the park: conservation of African elephants (Loxodonta africana) in Namibia. Conservation Physiology 5, cox067.
Being stressed outside the park: conservation of African elephants (Loxodonta africana) in Namibia.Crossref | GoogleScholarGoogle Scholar | 29270294PubMed |

Jachowski, D. S., Slotow, R., and Millspaugh, J. J. (2012). Physiological stress and refuge behavior by african elephants. PLoS One 7, e31818.
Physiological stress and refuge behavior by african elephants.Crossref | GoogleScholarGoogle Scholar | 22384079PubMed |

Jachowski, D. S., Slotow, R., and Millspaugh, J. J. (2013a). Delayed physiological acclimatization by African elephants following reintroduction. Animal Conservation 16, 575–583.
Delayed physiological acclimatization by African elephants following reintroduction.Crossref | GoogleScholarGoogle Scholar |

Jachowski, D. S., Slotow, R., and Millspaugh, J. J. (2013b). Corridor use and streaking behavior by African elephants in relation to physiological state. Biological Conservation 167, 276–282.
Corridor use and streaking behavior by African elephants in relation to physiological state.Crossref | GoogleScholarGoogle Scholar |

Jachowski, D.S., Montgomery, R.A., Slotow, R., and Millspaugh, J.J. (2013c). Unravelling complex associations between physiological state and movement of African elephants. Functional Ecology 27, 1166–1175.
Unravelling complex associations between physiological state and movement of African elephants.Crossref | GoogleScholarGoogle Scholar |

Kenward, M. G., and Roger, J. H. (1997). Small sample inference for fixed effects from restricted maximum likelihood. Biometrics 53, 983–997.
Small sample inference for fixed effects from restricted maximum likelihood.Crossref | GoogleScholarGoogle Scholar | 9333350PubMed |

Koolhaas, J. M., Korte, S. M., De Boer, S. F., Van Der Vegt, B. J., Can Reenen, C. G., Hopster, H., De Jong, I. C., Ruis, M. A. Q., and Blokhuis, H. J. (1999). Coping styles in animals: current status in behavior and stress-physiology. Neuroscience and Biobehavioral Reviews 23, 925–935.
Coping styles in animals: current status in behavior and stress-physiology.Crossref | GoogleScholarGoogle Scholar | 10580307PubMed |

Laws, N., Ganswindt, A., Heistermann, M., Harris, M., Harris, S., and Sherwin, C. (2007). A case study: fecal corticosteroid and behavior as indicators of welfare during relocation of an Asian elephant. Journal of Applied Animal Welfare Science 10, 349–358.
A case study: fecal corticosteroid and behavior as indicators of welfare during relocation of an Asian elephant.Crossref | GoogleScholarGoogle Scholar | 17970634PubMed |

Lindsey, P. A., Alexander, R., Mills, M. G. L., Romañach, S., and Woodroffe, R. (2007). Wildlife viewing preferences of visitors to protected areas in South Africa: implications for the role of ecotourism in conservation. Journal of Ecotourism 6, 19–33.
Wildlife viewing preferences of visitors to protected areas in South Africa: implications for the role of ecotourism in conservation.Crossref | GoogleScholarGoogle Scholar |

Loarie, S. R., van Aarde, R. J., and Pimm, S. L. (2009). Elephant seasonal vegetation preferences across dry and wet savannas. Biological Conservation 142, 3099–3107.
Elephant seasonal vegetation preferences across dry and wet savannas.Crossref | GoogleScholarGoogle Scholar |

Luke, S. G. (2017). Evaluating significance in linear mixed-effects models in R. Behavior Research Methods 49, 1494–1502.
Evaluating significance in linear mixed-effects models in R.Crossref | GoogleScholarGoogle Scholar | 27620283PubMed |

McEwen, B. S., and Wingfield, J. C. (2003). The concept of allostasis in biology and biomedicine. Hormones and Behavior 43, 2–15.
The concept of allostasis in biology and biomedicine.Crossref | GoogleScholarGoogle Scholar | 12614627PubMed |

Millspaugh, J. J., and Washburn, B. E. (2004). Use of fecal glucocorticoid metabolite measures in conservation biology research: considerations for application and interpretation. General and Comparative Endocrinology 138, 189–199.
Use of fecal glucocorticoid metabolite measures in conservation biology research: considerations for application and interpretation.Crossref | GoogleScholarGoogle Scholar | 15364201PubMed |

Millspaugh, J. J., Burke, T., Slotow, R., Washburn, B. E., and Woods, R. J. (2007). Stress response of working African elephants to transportation and safari adventures. The Journal of Wildlife Management 71, 1257–1260.
Stress response of working African elephants to transportation and safari adventures.Crossref | GoogleScholarGoogle Scholar |

Moss, C. J. (1996). Studying populations. In ‘Studying Elephants AWF Technical Handbook Series’. (Ed. K. Kangwana.) pp. 58–98. (African Wildlife Foundation: Nairobi, Kenya.)

Möstl, E., and Palme, R. (2002). Hormones as indicators of stress. Domestic Animal Endocrinology 23, 67–74.
Hormones as indicators of stress.Crossref | GoogleScholarGoogle Scholar | 12142227PubMed |

Möstl, E., Maggs, J. L., Schrötter, G., Besenfelder, U., and Palme, R. (2002). Measurement of cortisol metabolites in faeces of ruminants. Veterinary Research Communications 26, 127–139.
Measurement of cortisol metabolites in faeces of ruminants.Crossref | GoogleScholarGoogle Scholar | 11922482PubMed |

Mucina, L., and Rutherford, M. C. (Ed.) (2006). ‘The vegetation of South Africa, Lesotho and Swaziland.’ Strelitzia 19. (South African National Biodiversity Institute: Pretoria, South Africa.)

Munshi-South, J., Tchignoumba, L., Brown, J., Abbondanza, N., Maldonado, J. E., Henderson, A., and Alonso, A. (2008). Physiological indicators of stress in African forest elephants (Loxodonta africana cyclotis) in relation to petroleum operations in Gabon, Central Africa. Diversity & Distributions 14, 995–1003.
Physiological indicators of stress in African forest elephants (Loxodonta africana cyclotis) in relation to petroleum operations in Gabon, Central Africa.Crossref | GoogleScholarGoogle Scholar |

Nelson, R. J., and Kriegsfeld, L. J. (Ed.) (2017). ‘An Introduction to Behavioral Endocrinology.’ 5th edn. (Sinauer Associates, Inc. Publishers: Sunderland, MA, USA.)

Orams, M. B. (2002). Feeding wildlife as a tourism attraction: a review of issues and impacts. Tourism Management 23, 281–293.
Feeding wildlife as a tourism attraction: a review of issues and impacts.Crossref | GoogleScholarGoogle Scholar |

Palme, R. (2012). Monitoring stress hormone metabolites as a useful, non-invasive tool for welfare assessment in farm animals. Animal Welfare 21, 331–337.
Monitoring stress hormone metabolites as a useful, non-invasive tool for welfare assessment in farm animals.Crossref | GoogleScholarGoogle Scholar |

Palme, R. (2019). Non-invasive measurement of glucocorticoids: advances and problems. Physiology & Behavior 199, 229–243.
Non-invasive measurement of glucocorticoids: advances and problems.Crossref | GoogleScholarGoogle Scholar |

Piñeiro, A., Barja, I., Silván, G., and Illera, J. C. (2012). Effects of tourist pressure and reproduction on physiological stress response in wildcats: management implications for species conservation. Wildlife Research 39, 532–539.
Effects of tourist pressure and reproduction on physiological stress response in wildcats: management implications for species conservation.Crossref | GoogleScholarGoogle Scholar |

Pinter-Wollman, N., Isbell, L. A., and Hart, L. A. (2009). Assessing translocation outcome: comparing behavioral and physiological aspects of translocated and resident African elephants (Loxodonta africana). Biological Conservation 142, 1116–1124.
Assessing translocation outcome: comparing behavioral and physiological aspects of translocated and resident African elephants (Loxodonta africana).Crossref | GoogleScholarGoogle Scholar |

Poole, J. H. (1994). Sex differences in the behaviour of African elephants. In ‘The Differences between the Sexes’. (Eds R. V. Short, and E. Balaban.) pp. 331–346. (Cambridge University Press: Cambridge, UK.)

R Core Team (2000). ‘R: a Language and Environment for Statistical Computing.’ (R Foundation for Statistical Computing: Vienna, Austria.) Available at http://www.R-project.org/ [verified 12 February 2019].

Ranaweerage, E., Ranjeewa, A. D. G., and Sugimoto, K. (2015). Tourism-induced disturbance of wildlife in protected areas: a case study of free ranging elephants in Sri Lanka. Global Ecology and Conservation 4, 625–631.
Tourism-induced disturbance of wildlife in protected areas: a case study of free ranging elephants in Sri Lanka.Crossref | GoogleScholarGoogle Scholar |

Rehnus, M., Wehrle, M., and Palme, R. (2014). Mountain hares Lepus timidus and tourism: stress events and reactions. Journal of Applied Ecology 51, 6–12.
Mountain hares Lepus timidus and tourism: stress events and reactions.Crossref | GoogleScholarGoogle Scholar |

Reynolds, P. C., and Braithwaite, D. (2001). Towards a conceptual framework for wildlife tourism. Tourism Management 22, 31–42.
Towards a conceptual framework for wildlife tourism.Crossref | GoogleScholarGoogle Scholar |

Sapolsky, R. M. (2002). Neuroendocrinology of the stress-response. In ‘Behavioral Endocrinology’. 2nd edn. (Eds J. B. Becker, S. M. Breedlove, D. Crews, and M. M. McCarthy) pp. 409–450. (MIT Press: Cambridge, MA, USA.)

Sarmah, J., Hazarika, C. R., Berkeley, E. V., Ganswindt, S. B., and Ganswindt, A. (2017). Non‐invasive assessment of adrenocortical function as a measure of stress in the endangered golden langur. Zoo Biology 36, 278–283.
Non‐invasive assessment of adrenocortical function as a measure of stress in the endangered golden langur.Crossref | GoogleScholarGoogle Scholar | 28804950PubMed |

Scheun, J., Bennett, N. C., Ganswindt, A., and Nowack, J. (2015). The hustle and bustle of city life: monitoring the effects of urbanisation in the African lesser bushbaby. Naturwissenschaften 102, 57.
The hustle and bustle of city life: monitoring the effects of urbanisation in the African lesser bushbaby.Crossref | GoogleScholarGoogle Scholar | 26336811PubMed |

Sheriff, M. J., Dantzer, B., Delehanty, B., Palme, R., and Boonstra, R. (2011). Measuring stress in wildlife: techniques for quantifying glucocorticoids. Oecologia 166, 869–887.
Measuring stress in wildlife: techniques for quantifying glucocorticoids.Crossref | GoogleScholarGoogle Scholar | 21344254PubMed |

Shutt, K., Heistermann, M., Kasim, A., Todd, A., Kalousova, B., Profosouva, I., Petrzelkova, K., Fuh, T., Dicky, J.-F., Bopalanzognako, J.-B., and Setchell, J. M. (2014). Effects of habituation, research and ecotourism on faecal glucocorticoid metabolites in wild western lowland gorillas: implications for conservation management. Biological Conservation 172, 72–79.
Effects of habituation, research and ecotourism on faecal glucocorticoid metabolites in wild western lowland gorillas: implications for conservation management.Crossref | GoogleScholarGoogle Scholar |

Singmann, H., Bolker, B., Westfall, J., and Aust, F. (2018). ‘afex: Analysis of Factorial Experiments.’ R package version 0.19-1. Available at https://CRAN.R-project.org/package=afex [verified 12 February 2019].

Slotow, R., Whyte, I., Hofmeyr, M., Kerley, G. H. I., Conway, T., and Scholes, R. J. (2008). Lethal management of elephants. In ‘Elephant Management: a Scientific Assessment for South Africa’. (Eds K. G. Scholes, and R. J. Mennell.) pp. 370–405. (Wits University Press: Johannesburg, South Africa.)

Szott, I. D., Pretorius, Y., and Koyama, N. (2019). Behavioural changes in African elephants in response to wildlife tourism. Journal of Zoology 308, 164–174.
Behavioural changes in African elephants in response to wildlife tourism.Crossref | GoogleScholarGoogle Scholar |

Teixeira, C., de Azevedo, C., Mendl, M., Cipreste, C., and Young, R. (2007). Revisiting translocation and reintroduction programmes: the importance of considering stress. Animal Behaviour 73, 1–13.
Revisiting translocation and reintroduction programmes: the importance of considering stress.Crossref | GoogleScholarGoogle Scholar |

Thiel, D., Jenni-Eiermann, S., Braunisch, V., Palme, R., and Jenni, L. (2008). Ski tourism affects habitat use and evokes a physiological stress response in capercaillie Tetrao urogallus: a new methodological approach. Journal of Applied Ecology 45, 845–853.
Ski tourism affects habitat use and evokes a physiological stress response in capercaillie Tetrao urogallus: a new methodological approach.Crossref | GoogleScholarGoogle Scholar |

Touma, C., and Palme, R. (2005). Measuring fecal glucocorticoid metabolites in mammals and birds: the importance of validation. Annals of the NY Acadademy of Science 1046, 54–74.
Measuring fecal glucocorticoid metabolites in mammals and birds: the importance of validation.Crossref | GoogleScholarGoogle Scholar |

Viljoen, J. J., Ganswindt, A., Palme, R., Reynecke, H. C., du Toit, J. T., and Langbauer, W. R. (2008). Measurement of concentrations of faecal glucocorticoid metabolites in free-ranging African elephants within the Kruger National Park. Koedoe 50, 18–21.
Measurement of concentrations of faecal glucocorticoid metabolites in free-ranging African elephants within the Kruger National Park.Crossref | GoogleScholarGoogle Scholar |

Webber, J. T., Henley, M. D., Pretorius, Y., Somers, M. J., and Ganswindt, A. (2018). Changes in African Elephant (Loxodonta africana) faecal steroid concentrations post-defaecation. Bothalia 48, 1–8.
Changes in African Elephant (Loxodonta africana) faecal steroid concentrations post-defaecation.Crossref | GoogleScholarGoogle Scholar |

Wickham, H. (Ed.) (2016). ‘ggplot2: Elegant Graphics for Data Analysis.’ (Springer: New York, NY, USA.)

Woolley, L. A., Millspaugh, J. J., Woods, R. J., van Rensburg, S. J., Mackey, R. L., Page, B., and Slotow, R. (2008). Population and individual elephant response to a catastrophic fire in Pilanesberg National Park. PLoS One 3, e3233.
Population and individual elephant response to a catastrophic fire in Pilanesberg National Park.Crossref | GoogleScholarGoogle Scholar | 18797503PubMed |

Zwijacz-Kozica, T., Selva, N., Barja, I., Silván, G., Martínez-Fernández, L., Illera, J. C., and Jodłowski, M. (2013). Concentration of fecal cortisol metabolites in chamois in relation to tourist pressure in Tatra National Park (south Poland). Acta Theriologica 58, 215–222.
Concentration of fecal cortisol metabolites in chamois in relation to tourist pressure in Tatra National Park (south Poland).Crossref | GoogleScholarGoogle Scholar |