Invasive species are widely posited as a major threat to native biodiversity worldwide. However, in urban and post-industrial environments, invasive species often contribute to the formation of novel ecosystems that support critical ecosystem services for Earths others. Despite this, current management approaches typically prioritise control and eradication, with little regard for local ecological contexts or the functional roles invasive species play. As a result, the removal of certain invasive species from urban environments can lead to a reduction in both functional and species diversity. We argue that a multi-species justice (MSJ) framework offers a productive way to engage with the complexity, uncertainty, and contested values surrounding invasive species by extending justice. Using an urban green space case study, we propose MSJ as a way of managing the tensions between nativeness and invasion. We invite a rethinking of how nativeness and flourishing are understood and enacted in shared urban environments.

The Earth is confronting a biodiversity and species extinction crisis, brought about by development-driven habitat loss and fragmentation and exacerbated by anthropogenic climate change. It has long been recognised that biodiversity decline is driven by a set of interrelated anthropogenic pressures. The main suite of factors acting singly and synergistically was characterised by Diamond et al. as the "Evil Quartet" behind the extinction crisis: habitat destruction, overexploitation/overharvesting, invasive species, and secondary loss through co-extinction. Wilson added human activities such as pollution and overpopulation as additional factors accelerating biodiversity loss, while more recently, the dramatic impacts of climate change on extinction risk have been embedded in this framework.

Invasive plant species are species introduced outside of their natural range that have one or more negative impacts, and are widely considered to be a major driver of global biodiversity loss. By outcompeting native vegetation for essential resources such as light, water, and nutrients, they can fundamentally alter community composition and ecosystem functioning. This displacement of native flora disrupts trophic interactions, leading to declines in native fauna reliant on indigenous plants for food, shelter, and other ecological services. Additionally, many invasive species modify critical ecological processes, including fire regimes, nutrient cycling, and hydrology, exacerbating habitat degradation and further reducing native biodiversity. The global spread of invasive plants is strongly associated with human activities such as land-use change, urbanisation, and global trade, underscoring their central role in the accelerating decline of biodiversity worldwide. As such, it is unsurprising that active removal of invasive species has long been seen in conservation biology as a "nasty necessity". Conservation discourse has often been informed by a paradigm that native plant species inherently support native biodiversity, whereas non-native species, and particularly invasive non-native species, are viewed as threats to ecological integrity. Notwithstanding the lively debates surrounding the meaning and value of terms like 'nativeness' and 'invasiveness', in urban environments, native plants are said to support higher faunal diversity and support ecosystem services more effectively than non-native plants. However, such binary framing fails to capture the ecological complexity of species interactions at the local scale. While some non-native species may act as invasive and highly disruptive agents in certain ecosystems, in others they may provide important ecological functions or support novel biodiversity assemblages. Consequently, indiscriminate removal of non-native species may produce unintended negative consequences for particular components of biodiversity, especially in highly modified ecosystems.

Multispecies justice (MSJ) approaches offer a conceptual and practical framework for renegotiating these tensions in disrupted urban and post-industrial ecologies. MSJ extends justice beyond humans to recognise all Earth beings and the relationships that sustain them, thereby recognising them as subjects of justice. It also suggests that understandings of value need to be recast beyond narrow anthropocentric frameworks. In this sense, MSJ is an approach that enables a more complex engagement with the value of invasive species in disrupted ecosystems, weakening the often-intractable polarity of native/invasive debates in landscape management. In fact, an MSJ approach may suggest that in certain contexts, justice would favour support for invasive species and the Earth others they can support. MSJ does this by providing a framework within which we can critically and constructively reflect on which species and ecosystems are being privileged or ignored in specific contexts, and a pragmatic mechanism for representation of Earths others in decision-making processes.

Here, we apply an MSJ lens to the nominally invasive species, Lantana camara L. (hereinafter lantana). Native to Central and South America, lantana has been named as one of the 100 worst invasive alien species and the second-most widespread invasive vascular plant species worldwide. It is commonly viewed as an aggressive and fast-growing plant that can thrive on saline to acidic and fertile or infertile soils. Its allelopathic properties and ecological resilience also allow it to colonise a wide range of climate and precipitation niches. Invasion risk is considered to be high in Africa, Australia, Oceania and South America, and will increase across all continents under global heating. Invasive risk assessments such as this focus solely on the biophysical, however, and do not include the social, political, legal and policy elements of the novel ecosystem phenomenon. Novel ecosystems can be sites of contestation, offering political spaces for supporting new urban socio-environmental futures and environmental and climate justice, with emphasis in the literature on the co-benefits and costs of novel ecosystems to humans. To deal with intractable conflicts associated with invasive species like lantana, it is critical to consider the co-benefits and costs and the processes and practices that lead to these outcomes over time.