Photo credit: Gary Whyte @ Unsplash
The third chapter of my PhD was recently published. This work looked at leopard scent marking behaviours and how they might be impacted by environmental features, like roads. An overview:
Scent marking is a type of communication where individuals leave chemical signals that contain information in the environment. These marks (and where they are placed in the environment) can contain information on things like who owns a territory, the sexual status of the signaler, and the fitness of individuals. For species where individuals occur in low densities or cover large areas, and so who are unlikely to meet others of the same species, scent marks can help individuals coordinate movements and maintain social structure. For example, scent marks can help individuals find each other for mating, maintain boundaries with territorial neighbours, and keep track of members within their social group.
On the other hand, scent marks can be costly to produce. There are energetic costs associated with producing scent marks and with travelling around landscapes to place marks in the right areas. There are also costs if marks are encountered by species who use them to cause signalers harm or steal their resources (e.g. food). As a result, species can use different strategies to reduce signaling costs and increase the chances of scent marks being encountered by the right individuals. One strategy, for example, might involve changing where scent marks are placed in the environment. For many species, relatively little is known of how scent marks are distributed across the landscape and how this might be impacted by the environment.
I used data collected from following leopards and GPS radio collars to look at leopard scent marking behaviours in the Okavango Delta. Leopards are territorial. So, I looked at how leopard scent marking behaviours change across areas of their territories (central v boundary areas) and across the pathways they travel along (natural v roads).
In a nutshell, I found that leopards within our study area visited scent marking sites on roads in boundary areas of their territory more quickly than those elsewhere, perhaps to keep boundary scent marks fresh to deter intruders. I also found evidence that roads function as key locations for chemical information. Leopards scent-marked over four times as frequently and investigated over three times as frequently when travelling on roads than when travelling along natural routes. This means that these human-made features now play an important role in leopard communication in this landscape.
Understanding how animals communicate and how human changes to the landscape can impact this is key in ecology. It can help us to document and so reduce the negative impacts that we might be having on species. More than that, it can also pave the way for novel approaches for reducing human-wildlife conflict - like the bio-boundary project, run by my collaborators at Botswana Predator Conservation. .
To read my full paper, head on over to: https://www.sciencedirect.com/science/article/abs/pii/S000334721930418X
Or send me a message to get an author-copy.