Using citizen science data to define and track restoration targets in urban areas

Abstract

1. Habitat fragmentation and land degradation, directly and indirectly caused by urbanization, are drastically altering the world's ecosystems and are therefore driving an imperative for ecological restoration within the world's cities. Current methods for the implementation and monitoring of restoration are limited. Restoration ecology needs cost-effective and repeatable tools for tracking changes at global scales, but with local relevance. 2. We propose the Urban Greenspace Integrity Index-a locally relevant measure of an urban greenspace's response to urbanization, derived from widely accessible citizen science data. Unlike classical measurements of biodiversity (e.g. species richness, species diversity), this index measures species-specific responses to continuous measures of urbanization. 3. Increases in this index are evidence of a successful urban restoration project; that is, restoration results in a community shift that favours urban-sensitive species. Importantly, data for this index are easily and efficiently collected by citizen scientists, providing long-term repeatable data. This urban index, calculated from greenspace surveys, correlates with and complements traditional biodiversity metrics. 4. Synthesis and applications. Policymakers and practitioners can use the index-a measure of the urbanness of the local bird community-to define and track restoration of urban ecosystems, effectively measuring changes in biodiversity in response to urbanization: measuring whether the urbanness of the bird community changes through time. Importantly, this index can be calculated using citizen science data, providing a potentially long-term monitoring effort of restoration projects. K E Y W O R D S alpha diversity, beta diversity, bird surveys, citizen science, gamma diversity, restoration, urban birds, urbanization | 1999 Journal of Applied Ecology CALLAGHAN et AL.

A continental measure of urbanness predicts avian response to local urbanization

“…For each buffer, raw radiance values were used -after filtering of the data to minimize the influence of fires, degraded data and other light source contamination (Elvidge et al 2017) -between 2013-2017 and the average raw radiance value was taken as an annual composite. This approach of assigning urban scores shows strong agreements with other measures of urbanization such as human population density (Callaghan et al 2019a(Callaghan et al , 2019b. Each species' observations then corresponded to a different distribution of VIIRS night-time lights (Fig.…”

“…This was done by taking the average radiance of night-time lights within a 5 km buffer of each checklist. A buffer was used to minimize any bias in eBird sampling protocols (e.g., mis-placement of eBird checklists by participants, and to account for travelling checklists throughout an area) and the size of the buffer has no discernible influence on the relative urban-score differences among species (Callaghan et al 2019a). We used the VIIRS night-time lights (Elvidge et al 2017) as a proxy for urbanization because it is correlated positively with impervious surface cover and human population density (Pandey et al 2013, Zhang and Seto 2013, Stathakis et al 2015) and because of its global availability and ease of use with Google Earth Engine (Gorelick et al 2017).…”

“…1), and we defined the median of this distribution as a species-specific urban-tolerance score. For more methodological details, and a published list of species-specific urban scores, see Callaghan et al (2019aCallaghan et al ( , 2019b.…”

A continental measure of urbanness predicts avian response to local urbanization

“…Our results provide empirical evidence that continental-scale data reflects local-scale relevance, albeit within one localized study site. These species-specific urban scores have the ability to move beyond species-specific measures to community-level measures of response to urbanization (Callaghan et al 2019a). And this community-level index can be tracked through time (among years) in response to restoration and/or degradation of urban greenspaces, highlighting the success or failures of restoration projects, for instance.…”

“…A buffer was used to minimize any bias in eBird sampling protocols (e.g. mis-placement of eBird checklists by participants, and to account for travelling checklists throughout an area) and the size of the buffer has no discernible influence on the relative urban-score differences among species (Callaghan et al 2019a). We used the VIIRS night-time lights (Elvidge et al 2017) as a proxy for urbanization because it is correlated positively with impervious surface cover and human population density (Pandey et al 2013, Zhang and Seto 2013, Stathakis et al 2015 and because of its global availability and ease of use with Google Earth Engine (Gorelick et al 2017).…”