Emerging laws must not protect stray cats and their impacts

Our moral circles—that is, the entities believed as worthy of moral concern and thus deserving moral considerations—have historically expanded beyond humans to include also nonhuman beings (Crimston et al., 2018). As a result, various emerging legal instruments around the world have been granting rights to animals. However, the inclusion of animals within moral circles is subjected to important biases, with a preference for charismatic, familiar, and beautiful vertebrates (Klebl et al., 2021). We argue that legal instruments embracing such biases may jeopardize biodiversity conservation.

FIGURE 1. Schematic representation of the known impacts of stray colony cats on biodiversity and humans. References cited for each impact category: predation (Loss et al., 2013); hybridization (Tiesmeyer et al., 2020); zoonoses (Milne et al., 2020); diseases (Chiu et al., 2019; Meli et al., 2010)

In February 2022, the Spanish government approved a draft law elaborated by the Ministry of Social Rights and 2030 Agenda to restructure most human–animal interactions (https://www.mdsocialesa2030.gob.es/servicio-a-la-ciudadania/proyectos-normativos/documentos/AP_LEY_ANIMALES.pdf). However, as it focuses on a few domestic species, the draft conflicts with several European and Spanish laws and key management strategies for biodiversity conservation. The draft pays particular attention to stray-cat colonies, that is high-density groups of unowned cats sustained by an artificial provision of resources. It intends to grant them protection and support, both nutritional and veterinary (to be provided by public local administrations), and to recognize an official status to their voluntary caretakers. Moreover, it prohibits their elimination, replacing culling (which has successfully eradicated cat populations on certain islands; Nogales et al., 2004) by fertility control (Trap-Neuter-Return/Release, TNR), which is considered more ethical. However, TNR only enables population reduction when applied at high rates over long time-frames and in spatial contiguity, at very high costs, and with compensatory effects that should be simultaneously managed (Gunther et al., 2022). Such complex, frequently unaffordable management would result in TNR perpetuating or even increasing the already high number of stray cats in cities and rural areas, thus maintaining (in the short-term) and then boosting (over longer time frames) their devastating impacts on biodiversity. Although challenging, the medium-term objective of environmental laws should be the disappearance of feral cats including cat colonies, which should be monitored through quantitative indicators related to the number of colonies and cats. To achieve this target, it is key to raise societal awareness about the detrimental effects that cats exert on biodiversity and public health (Figure 1) through effective communication (Dubois et al., 2017).

FIGURE 2. Stray cat preying on an endemic lizard (Gallotia galloti) near a cat colony located on Tenerife, Canary Islands. Photo by Dailos Hernández-Brito

The domestic cat has been implicated in more than a quarter of contemporary bird, mammal, and reptile extinctions worldwide, and is considered the most damaging invasive predators (Doherty et al., 2016). Predation by cats is the most important cause of small mammal and bird mortality, ahead of roadkill, poisoning, or human hunters (Trouwborst et al., 2020). Contrary to popular belief, well-fed colony cats still hunt wild prey (Plimpton et al., 2021), and because of their high densities, stray-cats often exert impacts on prey populations that are several times greater than native predators (Trouwborst et al., 2020). Cat impacts are particularly severe on islands, and the Spanish law will undoubtedly hinder the conservation of endemic Canary and Balearic faunas (Figure 2). Besides predation, cats also act as vectors and reservoirs for numerous diseases that can endanger wildlife (Meli et al., 2010) and harm public health (Milne et al., 2020). Stray-cat colonies may play a particularly important role in disease dynamics due to the high density of individuals and their intense interactions within colonies and with owned and feral cats (Trouwborst et al., 2020).

It is contradictory that the same Ministry charged with meeting the goals of the 2030 Agenda, including halting biodiversity loss, is proposing the enhancement and sustainment of a powerful driver of biodiversity loss. Although the wildlife management can sometimes trigger ethical challenges, prioritizing the well-being and fates of individuals of a few favored animal species over the conservation of species, populations, ecosystem functioning, and global biodiversity will promote homogeneous impoverished biotas dominated by a handful of privileged species (Griffin et al., 2020). While attending to animal welfare issues, legal instruments should unequivocally seek to reduce the negative impacts of free-roaming cats by minimizing their numbers in the shortest time and limiting outdoor access of owned cats as much as possible.

ACKNOWLEDGMENTS

The authors would like to thank all researchers who have kindly contributed to the discussion of this conservation problem in Spain.

CONFLICTS OF INTEREST

The authors declare no conflicts of interest.

AUTHOR CONTRIBUTIONS

All authors discussed the problem and wrote the paper.

DATA AVAILABILITY STATEMENT

The draft of the law (in Spanish) can be found at: https://www.mdsocialesa2030.gob.es/servicio-a-la-ciudadania/proyectos-normativos/documentos/AP_LEY_ANIMALES.pdf.