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

Paul Rose,Michelle O’Brien,Jack Boultwood

doi:10.3390/ani11071982

Abstract

Simple SummaryThe visitor effect describes how zoo animals respond to the presence of visitors to their enclosures in a positive, negative or neutral manner. The period of enforced closure of zoos due to the COVID-19 pandemic in March 2020 (and subsequent reopening later that year) allowed for the effect of visitor presence to be evaluated on several species of amphibian. Results have shown that amphibian visibility (i.e., likelihood to be on show in their enclosure) is potentially influenced by the presence of people, and therefore, enclosure layout, collection planning and amphibian husbandry should consider how to minimize any negative influences of the viewing public.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.

Highlights

The importance of measuring, understanding, and assessing animal welfare has become a focus and priority in recent years for the modern zoological collection
Due to a poor understanding of many amphibian behaviours and their wider natural history, amphibian welfare assessments are often based on an individual’s physical health status and reproductive output, as well as the suitability of environmental parameters, provision of natural furnishings to suggest the absence of poor welfare [2,11] and an opportunity for assumed normal behaviour patterns [10]
Amphibian visibility declined for the period when visitors were allowed back into the attraction in August and September, whilst the presence of increased numbers of staff “cleaners” appears to have little effect on animals being on display (Figure 1). The exception to this pattern was the Golden Mantella Exhibit, where more animals are visible in September compared to other periods of the year; a drop in the number of visible frogs within this exhibit was noted in the first month of visitor presence (August), in conjunction with the pattern seen in other species/exhibits

Summary

Introduction

The importance of measuring, understanding, and assessing animal welfare has become a focus and priority in recent years for the modern zoological collection. All zoo- and aquarium-housed species (here after “zoo species”) benefit from welfare measurement and assessment as the results from such initiatives can help inform species-relevant decisions related to the animal’s husbandry and management [1]. Our gap in understanding behaviours, environmental interactions and enclosure use of amphibians, when compared to mammals, may contribute to the low study rate of welfare assessments related to these species [4], as they can be understudied in the zoo [3,5]. The low availability of welfare assessment methods (and their outputs) for amphibians leaves opportunities for positive welfare to be undiscovered, poorer welfare situations to be unrectified and advances to husbandry to be potentially hidden [6]. Due to a poor understanding of many amphibian behaviours and their wider natural history, amphibian welfare assessments are often based on an individual’s physical health status and reproductive output, as well as the suitability of environmental parameters, provision of natural furnishings to suggest the absence of poor welfare [2,11] and an opportunity for assumed normal behaviour patterns [10]

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