Humans have a long history of protecting certain elements of nature. The concepts and values underlying conservation initiatives, however, have changed repeatedly [1]. Conservation efforts in the 20th century focused primarily on preserving landscapes free of human influence and on preventing the erosion of biodiversity, with an emphasis on protecting rare species from extinction. The last 20 years have seen the emergence of additional concepts that emphasise the resilience of nature and the ‘services’ that nature contributes to human well-being [2,3]. These novel approaches are promoted by some conservation leaders under the assumption that they will broaden the social support for conservation goals [4,5]. The advent of more socially inclusive approaches to conservation biology raises interesting and profound questions regarding the dimensions of the living world we seek to preserve and the political process that is used to specify appropriate conservation objectives.

Non-native species, and how they are valued, are at the heart of these ongoing debates. For the last several decades, non-native species have been portrayed by scientists primarily as a threat to society because a subset can cause economic harm, human-health issues, or the loss of native biodiversity [6,7]. The view that non-native species are potentially undesirable persists in indicators used to track progress towards targets of the Convention on Biological Diversity (CBD), where they only appear as a numerical predictor for future invasion events (Aichi Target 9) [8].

More recently, scientists have also documented the potential positive contributions of non-native species to regional species richness [9,10], conservation goals [11], and to the ecosystem services they contribute to certain stakeholders within society [12–14]. In some instances, non-native species are rapidly appreciated for their cultural ecosystem services. For example, citizen groups have lobbied for the protection of non-native Eucalyptus trees in California and non-native dingos in Australia [11]. The potentially positive contributions of non-native species to biodiversity and to the long-term welfare of humans are missing from current biodiversity indicators (Table 1). This raises the following questions: Are non-native species part of ‘nature’ or ‘biodiversity’ that we wish to preserve? If so, can they be integrated into a conservation planning process in a way that recognises their potential for undesirable effects but also captures their potential positive contributions to biodiversity and society?

Biodiversity is a complex notion and the indicators that are used to track it [16] are a reflection of available information, objectives, and values, which all can vary culturally and with time [3,28]. However, it is important to ask under what circumstances it might be scientifically and politically desirable to modify some biodiversity indicators to include all species in light of ongoing preparations for the Post-2020 Strategic Plan of CBD, ongoing assessments by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), and forthcoming national implementation of the Sustainable Development Goals (SDGs).