Bill Bateman & Trish Fleming.  Humans innately like to categorise things.  Perhaps this helps us to compartmentalise and understand the world.  Zoology, and other life sciences, tend not to be so amenable to this; taxonomically and ecologically and physiologically and genetically there is always overlap, there is always some confusion.  The study of behaviour is particularly messy, which is why quite often, when we look closely for patterns, we are surprised to discover that, what seemed obvious and intuitive, is often not supported by empirical data.  We describe an example of this conundrum in our recent paper “Are negative effects of tourist activities on wildlife over-reported? A review of assessment methods and empirical results” published this week in Biological Conservation.

Ecotourism, by which we mean ‘responsible travel to natural areas that conserves the environment, sustains the well-being of the local people, and involves interpretation and education’, or, more narrowly ‘travel with a primary interest in the natural history of a destination’ has been promoted as a powerful conservation tool, but at the same time there has been much concern of the negative influences of such activities as bird watching, hiking, whale watching, shark diving etc.  As a result there have been many papers exploring how animals react to being followed by or peered at by humans or having to share their habitat with swimmers, skiers, cyclists etc.

We identified in the literature three main types of measures of animals’ responses to ecotourism:

1. Avoidance responses (such as alert distance, flight initiation distance, distance fled and behaviour associated with movement away)
2. Time budgets (less time spent foraging/ feeding, resting, grooming, nursing/attending nest, engaging in social behaviour or play), increases in wariness/vigilance or locomotion, increased aggression with conspecifics, or expression of displacement ‘comfort’ behaviour)
3. Physiological and breeding responses (the measures above often come with related physiological responses such as elevated heart rate or release of stress hormones; this can be particularly significant at breeding colonies, resulting in increased metabolic rates, reduced growth rates, impaired responses to injuries/healing wounds, reduced investment in rearing young, and reduced reproductive success).

Many studies measure only one of these responses, few do two (e.g. our recent paper on quokkas’ responses to ecotourists on Rottnest Island looked at the first two measures) and hardly any explore all three.

We trawled the journals for relevant papers and looked at all the data presented (learning along the way that many papers fail to present all their data) and calculated the effect size of the data (i.e. the strength of the reported response), and whether it was a negative or positive response to ecotourist activities, and how the authors interpreted their results.

What did this meta-analysis tell us?  Well, first of all there was a taxonomic bias: of 99 species, 48 species were birds and 37 were mammals, with few studies on other taxa: reptiles: 5 species, bony fish 2 species, cartilaginous fish: 7 species and invertebrates: 1 species.  Secondly, without going in to too much detail (please read the paper!), we found that most authors claimed that their study showed a negative response by their study species to ecotourist activity.

But of course, it is not that simple – the effect size data showed that most studies actually showed positive or neutral responses by the study animals to ecotourist behaviour.  This does not mean that all ecotourist activities are not bad for the animals they are focussed on – the physiological data indicated that many animals show a strong negative response to even apparently benign activities such as bird watching.  What we need to do in future ecotourist impact research is be aware that measuring the impact of humans on animals is really, unsurprisingly perhaps, quite complex, with very different responses depending on the nature of the relationship between the animal species and the ecotourists.  If we want to gather data that will help us conserve species “there is no single optimal method to quantify anthropogenic stressors, and […] in addition to the precise goals and fiscal constraints of a project, the context, species, and level of temporal change to be measured are also considerations.”

Overall, however, our study indicates that negative effects of ecotourism on animals appears to be over-reported, and that issues, while real, may not be as bad as we might intuitively fear.  This does not release us from the need to be considerate in our ecotourist activities; on the contrary, we should continue more data collection to ensure management that maintains ecotourism as beneficial and an active contributor to conservation.