Ecotourism effects on health and immunity of Magellanic penguins at two reproductive colonies with disparate touristic regimes and population trends

The influence of tourist visitation on the heterophyl to lymphocyte ratios and trophic values of Magellanic penguins (Spheniscus magellanicus) at Martillo Island, Argentina

Wildlife tourism is increasing worldwide and monitoring the impact of tourism on wild populations is of the utmost importance for species conservation. The Magellanic penguin Spheniscus magellanicus colony at Martillo Island, Argentina, was studied in the 2016-2020 breeding seasons. In all seasons, adults and chicks belonged to: (i) an area close to or within the tourist trail or (ii) an area far from the tourist trail and out of sight of the tourists. Blood samples were taken for carbon and nitrogen stable isotope composition, in order to estimate trophic niches, and for smears that were made in situ and were then stained in the laboratory where leucocyte counts and differentiation were made under optical microscope. Heterophil to lymphocyte ratios were used as proxies of stress. Repeated sampling showed individual stress levels reduced while wintering. In 2017, stress levels and trophic values were lower than 2018 for the same individuals. Trophic levels did not differ between tourism and no tourism areas within each season, and differed between 2017 and the remaining seasons, indicating a possible diet shift that year. Stress levels were higher for the tourism area than the no tourism area for adults and chicks in all years except for 2020, when stress levels in the tourism area were lower and similar to the no tourism area that year and previous years. Vessel transit within the Beagle Channel and tourist visitation to the penguin colony was greatly reduced in 2020 due to the Covid-19 pandemic. A combination of internal characteristics and external factors may be affecting the stress physiology of individuals. Therefore, future research should include sampling of multiple aspects of penguin physiology, behaviour and environmental context in order to evaluate each effect on Magellanic penguin stress and, ultimately, inform the conservation of this iconic species in time.

Evaluation of the Effects of Administering Ultradiluted Avena sativa and Echinacea angustifolia on the Hematological Parameters of Magellanic penguins (Spheniscus magellanicus) during the Reproductive Period

BACKGROUND AND AIMS

Penguins are seabirds that manifest physiological and immunological alterations during the reproductive season. The objectives of this study were to evaluate the laboratory parameters of male and female Magellanic penguins and to determine the penguins' hematological response to homeopathic medicines during that reproductive period.

METHODS

Penguins (N = 18), kept under human care in a zoological park setting, were evaluated during the reproductive period and were divided randomly into two groups: a group subjected to treatment with Echinacea angustifolia 6cH and Avena sativa 6cH (N = 8; four breeding couples), and a placebo control group (N = 10; five breeding couples). The investigators were blinded to treatment allocation. Two-way ANOVA was performed to determine whether the experimental group (control or verum) and the sex of the animal had any significant effect on the variation of each hematological parameter between the samples. One-way ANOVA was performed on hematological parameters for which the sex did not present a significant effect. The significance level was p ≤0.05.

RESULTS

Significant effects were seen regarding the following: mean corpuscular volume (MCV), in which the verum group showed an increase (29.78 ± 52.95 fL) while the control group showed stability/reduction (-3.08 ± 46.36 fL) (p = 0.049); proportion of heterophils, in which the verum group showed a less marked increase (8.38 ± 12.53%) than that of the control group (18.00 ± 9.37%) (p = 0.010); lymphocyte concentration, in which the verum group showed less marked reduction (-4.39 ± 2.21 × 109 cells/L) than that of the control group (-1.56 ± 2.76 × 109 cells/L) (p = 0.001); and proportion of lymphocytes, in which the verum group showed a less marked reduction (-6.75 ± 10.35%) than that of the control group (-17.3 ± 8.73%) (p = 0.002).

CONCLUSION

Comparison of samples collected before and during the reproductive period showed that, regardless of group allocation, there were differences in the effects on MCV, heterophils and lymphocytes. Treatment with Echinacea angustifolia and Avena sativa resulted in maintenance of lymphocyte levels in Magellanic penguins during the breeding period, thus aiding these birds' immunity.

Integrative assessment of immunity, health-state, growth and survival of Magellanic penguin chicks in a colony exposed to ecotourism

Accumulating reports of negative impacts of tourist activities on wildlife emphasize the importance of closely monitoring focal populations. Although some effects are readily noticed, more subtle ones such as changes in physiological functions of individuals might go overlooked. Based on evidence of altered physiology associated with ecotourism on Magellanic penguins Spheniscus magellanicus, here we performed an integrated assessment using a diverse physiological toolkit together with more traditional fitness-related measures to better understand mechanisms and potential consequences. Chicks exposed to tourism showed altered immune parameters and elevated flea prevalence, reinforcing previous findings. Tourism-exposed female, but not male, chicks also showed relatively lower hematocrit and plasma protein levels, providing evidence consistent with a sex-specific response to tourist visitation. Physiological alterations detected in tourism-exposed young chicks (week 1-2) were maintained and the effect on flea infestation increased during the study period (week 4-5 of post-hatch). Despite the effects on physiology, these did not seem to translate into immediate fitness costs. No detectable tourism effects were found on brood sex ratios, chick growth and body condition, and survival until week 5-6 post-hatch. We detected no effects on reproductive output and only a marginal effect on nest survival during incubation despite previous reports of tourism-associated alterations in stress indices of adults. This disconnection could result if the physiological changes are not strong enough to impact fitness, if effects balance each other out, or if changes are part of a copying strategy. Alternatively, the physiological alterations might only show impacts later in the brooding cycle or even after chick emancipation from their parents. Our results suggest that integrative monitoring of potential anthropogenic impacts on wildlife should include evaluation of physiological mechanisms and individual-level responses in populations exposed to human activities.

Physiological parameters of a plover during nonbreeding and breeding seasons in Patagonia, Argentina

Migratory shorebirds are the most threatened avian species due to the effects of human activities and climate change. Physiological parameters are useful to evaluate the health status of free-living animals. Here we investigated lymphocytes, heterophils, heterophils/lymphocytes, and glucose for female and male Two-banded Plovers (Charadrius falklandicus Latham, 1790) during nonbreeding (body moult) and breeding (incubation) seasons in coastal areas of northern Patagonia, Argentina. We also measured corticosterone for the first time for this species during the breeding season. Nonbreeding Two-banded Plovers were more likely to have higher physiological measurements that were not dependent on body moult nor body condition, being similar between sexes. Differences found in glucose are likely related to recent feeding in nonbreeding birds compared with fasting during incubation. The gregarious nonbreeding behaviour in comparison with the isolated breeding pairs would increase the risk of acquiring parasites and (or) pathogens inducing a response of the immune system reflected in higher values of lymphocytes. Baseline corticosterone during breeding was similar between sexes and were lower compared with other values reported for breeding plovers. Two-banded Plovers undergo energetically demanding physiological changes during the nonbreeding stage, strengthening the idea that conservation of the environmental resources at these locations may be more important than previously thought.

Different patterns of human activities in nature during Covid-19 pandemic and African swine fever outbreak confirm direct impact on wildlife disruption

Implementation of various restrictions to eradicate viral diseases has globally affected human activity and subsequently nature. But how can the altered routines of human activity (restrictions, lockdowns) affect wildlife behaviour? This study compared the differences between human and wildlife occurrences in the study forest area with acreage of 5430.6 ha in 2018 (African swine fever outbreak, complete entrance ban), 2019 (standard pattern) and 2020 (COVID-19 restrictions) during the breeding season. The number of visitors was lower by 64% in 2018 (non-respecting of the entry ban by forest visitors) compared to standard 2019, while in 2020, the number of visitors increased to 151%. In the COVID-19 period, distinct peaks in the number of visitors were observed between 8-11 AM and 4-7 PM. The peaks of wildlife activity were recorded between 4-7 AM and 9-12 PM. Animals avoided the localities that were visited by humans during the people-influenced time (24 h after people visit), which confirmed the direct negative impact of human activities on wildlife.

Response of Bolivian gray titi monkeys (Plecturocebus donacophilus) to an anthropogenic noise gradient: behavioral and hormonal correlates

Worldwide urban expansion and deforestation have caused a rapid decline of non-human primates in recent decades. Yet, little is known to what extent these animals can tolerate anthropogenic noise arising from roadway traffic and human presence in their habitat. We studied six family groups of titis residing at increasing distances from a busy highway, in a park promoting ecotourism near Santa Cruz de la Sierra, Bolivia. We mapped group movements, sampled the titis’ behavior, collected fecal samples from each study group and conducted experiments in which we used a mannequin simulating a human intrusion in their home range. We hypothesized that groups of titi monkeys exposed to higher levels of anthropogenic noise and human presence would react weakly to the mannequin and show higher concentrations of fecal cortisol compared with groups in least perturbed areas. Sound pressure measurements and systematic monitoring of soundscape inside the titis’ home ranges confirmed the presence of a noise gradient, best characterized by the root-mean-square (RMS) and median amplitude (M) acoustic indices; importantly, both anthropogenic noise and human presence co-varied. Study groups resided in small, overlapping home ranges and they spent most of their time resting and preferentially used the lower forest stratum for traveling and the higher levels for foraging. Focal sampling analysis revealed that the time spent moving by adult pairs was inversely correlated with noise, the behavioral change occurring within a gradient of minimum sound pressures ranging from 44 dB(A) to 52 dB(A). Validated enzyme-immunoassays of fecal samples however detected surprisingly low cortisol concentrations, unrelated to the changes observed in the RMS and M indices. Finally, titis’ response to the mannequin varied according to our expectation, with alarm calling being greater in distant groups relative to highway. Our study thus indicates reduced alarm calling through habituation to human presence and suggests a titis’ resilience to anthropogenic noise with little evidence of physiological stress.

The effectiveness of regulatory signs in controlling human behaviour and Northern gannet (Morus bassanus) disturbance during breeding: an experimental test

Human disturbance to wildlife is on the rise and disturbance management is a key activity in conservation. Although disturbance can be controlled with relative ease in nature reserves that are properly resourced and managed by employed staff, most reserves do not fall into this category, and most wildlife exists outside managed reserves entirely. Thus, developing and demonstrating the effectiveness of simple, low-cost approaches to minimising disturbance is an important objective in conservation. In this study we examine the effectiveness of regulatory signs in controlling the behaviour and impacts of visitors on a colonial island-nesting bird, the Northern gannet (Morus bassanus), on an unmanaged island. First, we found that the percentage of successful nests declined with proximity to the disturbed edge of the colony, and was much higher in an undisturbed control area. Second, the number of birds displaced by visitors correlated negatively with the minimum visitor approach distance. Third, visitor proximity to the colony was dramatically reduced in the presence of a regulatory sign in comparison to periods without signs, which resulted in fewer birds being displaced from their nests. Photographers were the only visitor group who didn’t always comply with the sign. Our results show that breeding success in a species often thought to be well adapted to human presence, suffers from tourist pressure, and that simple and informative regulatory signs can be a cost-effective way of reducing the disturbance caused by visitors at unmanaged wildlife sites.