Policy-relevant indicators for invasive alien species assessment and reporting

Abstract

Invasive alien species are repeatedly shown to be amongst the top threats to biodiversity globally. Robust indicators for measuring the status and trends of biological invasions are lacking, but essential for monitoring biological invasions and the effectiveness of interventions. Here, we formulate and demonstrate three such indicators that capture the key dimensions of species invasions, each a significant and necessary advance to inform invasive alien species policy targets: 1) Rate of Invasive Alien Species Spread, which provides modelled rates of ongoing introductions of species based on invasion discovery and reporting. 2) Impact Risk, that estimates invasive alien species impacts on the environment in space and time and provides a basis for nationally targeted prioritization of where best to invest in management efforts. 3) Status Information on invasive alien species, that tracks improvement in the essential dimensions of information needed to guide relevant policy and data collection and in support of assessing invasive alien species spread and impact. We show how proximal, model-informed status and trend indicators on invasive alien species can provide more effective global (and national) reporting on biological invasions, and how countries can contribute to supporting these indicators.

Relative importance of exotic species traits in determining invasiveness across levels of establishment: Example of freshwater fish

“…In this paper, we focused on the dimensions of invasiveness related to the establishment stage of invasions, thus disregarding the ecological impact of species. However, this impact lies at the core of management strategies, because it determines the type of response implemented to counter the current or future invasion effects (McGeoch et al, 2021). Nevertheless, the paucity of data make it difficult to conduct large‐scale studies (Bernery, Bellard, Courchamp, Brosse, Gozlan, et al, 2022; Thomsen et al, 2011).…”

Data-Driven Recommendations for Establishing Threshold Values for the NIS Trend Indicator in the Mediterranean Sea

“…Their continuous development and refinement are crucial for the effective implementation of environmental policies and the delivery of management targets [8]. When it comes to biological invasions, the trend in species introductions on any geographical scale is one of the most intuitive and commonly used metrics to describe and measure the intensity of the phenomenon, both in research and in policy [27], yet the relevant indicators for Europe and the Mediterranean are still not ready to be fully incorporated into GES assessments. In this work, we endeavoured to take the NIS trend indicator one step closer to being operational by developing a simple and practical methodology to determine reference periods and threshold levels.…”

“…Even when explicitly taking the effects of sampling efforts into account, however, the true rate of introduction may not be accurately inferred from the rate of detection [60], which is essentially measured when using data on the date of collection of species [43], and which depends on a number of factors, such as population growth rate and its effect on abundance or ease of recognition [61]. In this case, a modelling approach can be adopted to correct for detection rate vs. introduction rate, such as the one proposed by McGeoch et al [27], based on the model developed by Solow and Costello [62].…”

Distribution, drivers and restoration priorities of plant invasions in India

“…These global commitments are highlighted with United Nations' declaring the ongoing decade for ecosystem restoration. Yet, policies, management and research on biological invasions are presently constrained with unavailability of reliable information on distribution of invasive species and their key drivers (McGeoch et al, 2016). This knowledge gap is particularly problematic for the Global South, with high potential to conserve biodiversity relative to the Global North (Early et al, 2016).…”