As cities continue to expand outwards and the pressure for urban infill intensifies, there has been increased community concern around the protection and enhancement of urban natures. In land-use planning processes, the inability of nonhuman nature to communicate or deliberate in matters affecting them, tends to confine their participation to human interpretation and representation. Such representation is often framed by human-centred knowledge practices or by prevailing anthropocentric discourses that typically view nature as a resource for human consumption. Environmental activists, though, often offer an alternative representation based on experiential local knowledge. However, the perception their knowledge lacks ‘objective’ credibility hampers their authority and disrupts their ability to initiate change or garner significant political power. Thus, in the pursuit of spatial justice for nonhumans, what impact can environmental activists have on normative planning practice? This paper queries whether the alternative representation activists mobilise have the potential to disrupt the anthropocentric handling of nonhumans in planning practices. By analysing discourses presented by environmental activists and proponents in relation to the proposed subdivision of the Underwood Avenue bushland in Western Australia, it will demonstrate that the way humans talk about nature is complex, and in the case of highly contested planning processes they are often underpinned by specific strategies. It will suggest that the deployment of locally-led pro-conservation campaigns can have a positive impact on shifting public discourses of nature into a less anthropocentric, more environmentally-considered space.