Which index should I use? A comparison of indices for enclosure use studies

Abstract

Enclosure use assessments have gained popularity as one of the tools for animal welfare assessments and Post Occupancy Evaluations. There are now a plethora of studies and enclosure use indices available in published literature, and identification of the most appropriate index for each research question is often challenging. The benefits and limitations of four different enclosure use indices; Original and Modified Spread of Participation Index (SPI), Entropy, and Electivity Index were compared. Three artificial data sets were developed to represent the challenges commonly found in animal exhibits, and these indices were applied to these contrived enclosure settings. Three of the indices (Original SPI, Modified SPI, and Entropy) were used to assess a single measure of enclosure use variability. When zones within an exhibit were comparable in size, all three indices performed similarly. However, with less equal zone sizes, Modified SPI outperformed Original SPI and Entropy, suggesting that the Modified formula was more useful for assessing overall enclosure use variability under such conditions. Electivity Index assessed the use of individual zones, rather than the variability of use across the entire exhibit, and therefore could not be compared directly to the other three indices. This index is therefore most valuable for assessing individual resources, especially after exhibit modifications.

Effects of New Seal Introductions on Conspecific and Visitor Activity

“…During each experiment, the behaviors of the animals in each setting were recorded prior to and after the introduction of the new individuals (pre-introduction and post-introduction conditions, respectively). These data were recorded using written datasheets where instantaneous sampling [ 20 , 61 ] was used to record the behaviors. Researchers used the phone app MultiTimer that sounded a beep every minute, signaling the researchers to write down the behavior that the animal(s) were doing in that exact instant.…”

“…Visitor effects are defined as the ways in which visitors impact the behaviors of animals [ 16 ]. This has been commonly measured through animals’ hormone levels, spatial dispersion, visibility within an enclosure, and behavioral observations of the animals [ 16 , 20 , 21 , 22 ]. An increased visitor presence could elicit a positive, neutral, or negative impact on the currently exhibited animals [ 5 , 16 , 18 ].…”

“…Additionally, animals may become habituated to the presence of visitors and there is little to no effect of visitors on animal behavior, which would be categorized as a neutral visitor effect [ 16 , 26 ]. Furthermore, enclosure usage can be incorporated as a measure of behavioral welfare for captive animals, particularly when it is difficult to derive meaningful information from behaviors alone [ 20 , 22 ]. Visitor experiences , on the other hand, are defined as the ways in which animals, exhibits, and zoos/aquariums in general impact visitors.…”

Investigating Unused Tools for the Animal Behavioral Diversity Toolkit

“…This index is also slightly less sensitive to differences in sample size (e.g., as a result of out of sight animals) as the index is generated based on proportional data rather than raw counts [ 34 ]. Finally, it is worth pointing out that the Shannon–Wiener index has also been described as Entropy, which has similarly been used to assess enclosure use variability [ 13 , 35 , 36 ].…”

“…Behavioral diversity is a measure in that it can be applied alongside other welfare tools. In addition to behavior, this measure has been previously applied alongside other welfare-related metrics such as enclosure use indices [ 12 , 13 , 14 ] or assessment of glucocorticoid metabolites [ 10 , 15 ].…”