Stray Cats And Climate Change

The impact of stray and feral cats on the environment is something that researchers have continued to study from a variety of angles. Some have even called feral cats “one of the world’s most invasive species,” but they are also very closely associated with humans: the population density of “free-living, un-owned” cats has been shown to be “closely linked to human population density.” Cats, even feral ones, tend to stay near human populations as food and ad hoc shelter is more readily available when needed. As such, humans are often in the driver’s seat when it comes to “managing” these cat populations, and management decisions must take into account a variety of perspectives, from “animal (and human) welfare considerations, as well as environmental issues that focus on ecology and the conservation of biodiversity.”

This study explored the current spatial distribution of feral cats in New Zealand and used computer modelling to “investigate the potential impacts of climate change on future distributions.” They note that feral cats can have a profound impact on wildlife, citing a study that considers feral cats to be responsible for “at least 14% of extinctions of birds, mammals and reptiles globally in island environments.” For an island nation like New Zealand, the current and future distribution of cats and how it relates to the effects of climate change is very important. Changes in how birds use the local habitat and how those changes may bump up against the populations and habitats of feral cats could present a uniquely difficult set of challenges.

In two different “climate change-based scenarios,” the researchers found that there was a “consistent increase in the area and intensity of areas suitable for un-owned cats.” What this means is that, as temperatures shift (and generally get warmer), cats may venture into previously uninhabited areas to find suitable food and shelter sources. When the researchers overlaid protected areas of other species onto these “suitability maps” for cats, they were able to identify which protected areas “were more suitable for un-owned (cats) in current and a future climatic condition.” Though they do caution that these models are not foolproof and can be subject to change based on conditions, the researchers also say that their approach in general “could contribute to the development of un-owned cat management strategies through the establishment of NZ-wide suitability maps under both current and future conditions.”

This study is a particularly interesting one for companion animal advocates as it explores the issue of feral cats and predation from a perspective that is looking towards the future, rather than focusing on present or past statistics. The results of this study are obviously most relevant to New Zealand, but the premise of the study itself should have companion animal advocates taking notice. It’s not enough to simply consider how much feral cat populations do or don’t hunt “native species” — it’s also important to consider how a shifting climate (and other future changes) may erase the separation that exists between feral cats and some other species.