Bold Frogs or Shy Toads? How Did the COVID-19 Closure of Zoological Organisations Affect Amphibian Activity?

Abstract

Amphibians are an understudied group in the zoo-focussed literature. Whilst commonly housed in specialist exhibits and of real conservation value due to the global extinction crisis, amphibian welfare is not often investigated empirically in zoo settings. The limited research that is available suggests that enclosure design (structure, planting and naturalistic theming) has a positive impact on the time that amphibians will be on show to visitors. However, the categorisation of any “visitor effect” (i.e., influences of visitor presence on amphibian activity and time on display) is hard to find. The COVID-19 pandemic forced the closure of zoological organisations in the UK for several months from March 2020, with gradual re-openings from the summer into autumn and winter. This event provided a unique opportunity to study the effect of the lack of visitors, the presence of essential zoo staff only, the wider return of organisational staff, and then the return of visitors over a prolonged period. This project at WWT Slimbridge Wetlands Centre assessed the number of individuals of six species of amphibian—common toad (Bufo bufo), common frog (Rana temporaria), smooth newt (Lissotriton vulgaris), pool frog (Pelophylax lessonae), golden mantella (Mantella aurantiaca) and golden poison dart frog (Phyllobates terribilis)—visible to observers under different conditions. All amphibians were housed in a purpose-built indoor exhibit of individual enclosures and were recorded when visible (as a proportion of the total population of the enclosure) during closure, the return of extra centre staff and visitor periods. The results showed species-specific differences in visibility, with some species of amphibian being more likely to be on view when the presence of people at their enclosure was less likely or in smaller numbers. Such differences are likely related to the specific camouflage or anti-predation tactics in these focal species. Further study to quantify amphibian sensitivity to, and perception of, environmental change caused by public presence (e.g., light levels and sound) would be useful welfare-themed research extensions. Our results can help inform husbandry, collection planning and amphibian enclosure design to reduce any noticeable visitor effects, and provide a useful benchmark for further, more complex, welfare assessment measures.

The Effect of Visitors on Zoo Reptile Behaviour during the COVID-19 Pandemic

“…These outcomes reflect the diversity of responses to the lockdown identified in a range of taxa by other authors [19,21,28,47]. Common with the only other reptile-based study of the impact of lockdown ( [19]; saltwater crocodiles), the majority of reptile species in this study showed only a small, if any, response to changes in visitors' presence.…”

“…However, the stronger effects seen in some taxa highlighted that some reptiles may be sensitive to human presence. It is important to note that, like the amphibian study of Boultwood et al [21], we were unable to collect detailed behavioural data reflecting those collected by some other authors for our species [19,47,48] as a result of resource constraints during lockdown, and therefore, some behavioural changes that did not affect activity or visibility may have been undetected. It is important to note that, although we demonstrated effects of visitors on some species, our data did not allow us to attribute this to positive or negative changes in their welfare state.…”

“…This is a limitation imposed by the zoo context of the study, where the exhibits and stocking densities could not be controlled and where replicates were not available. In this way, this work was intended as a case study to highlight potential visitor impacts on a poorly studied group and to encourage further, more detailed research, as well as to provide some evidence base for collection planning and welfare mitigation in this group of animals [21]. As the enclosures were designed to best cater to the needs of the animals living in them, we chose to assume that we could consider the observed effects to be attributable to intrinsic differences between species or at least individual representative of those species used here, rather than enclosure effects.…”

“…In the absence of such data for reptiles, a recent study comparing amphibian (the only other terrestrial ectothermic vertebrate group) visibility during the COVID-19 lockdown periods and open periods found that all studied amphibians showed either an increase in visibility or maintained a consistent visibility for times of full lockdown and a decrease when visitors were present. However, visitors' presence had a greater effect on camouflaged species rather than aposematic species, with golden mantella (Mantella aurantiaca) and golden poison dart frogs (Phyllobates terribilis) habituating quicker to changes in visitor numbers than their camouflaged counterparts [21].…”

“…The unusual, prolonged closure and reopening periods of UK zoos during the 2020 lockdowns amidst the COVID-19 pandemic provided an opportunity to assess the effects of long-term absences of visitors on reptilian behaviours at ZSL London Zoo. This study aims to expand the understanding of human-animal interactions by comparing the visibility of a range of species during periods of visitors' presence and absence in a rapid assessment case study context similar to that provided for amphibians by Boultwood et al [21].…”