Ecological use of vertebrate surrogate species in ecosystem conservation

Highlights

• Freshwater species were disproportionately focused relative to the threats they face.

• Focal themes shift from pollution to climate change and conservation strategies.

• “SDM”, “protected areas” and “habitat selection” are possible hotspots in the future.

Abstract

Surrogate species approaches are widely employed by conservation biologists to help address biodiversity conservation issues when distribution and abundance data for most species of conservation concern are not available or are limited due to insufficient funding and support. However, global reviews of research statuses and trends in the ecological uses of various surrogate approaches in ecosystem conservation are relatively scarce. Here, to fill identified knowledge gaps, we comparatively analyze the research hotspots and trends of five surrogate approaches (i.e., keystone, flagship, umbrella, indicator, and focal species) in vertebrates based on research publications from 1962 to 2019. We found that surrogate species have increased focus since the 1990s. The five individual surrogate approaches showed clear differences in terms of scientific outputs and focal themes, which could be attributed to country/territory and journal preferences. We also found that research activities were mainly conducted in terrestrial ecosystems with mammals and birds, while freshwater species were disproportionately considered relative to the threats they face. In addition, we found that the focal themes changed from pollution monitoring to climate change and conservation strategy. Our study showed that “species distribution model”, “protected areas” and “habitat selection” are possible hotspots of future research using surrogate approaches under the consistent effects of climate change and habitat fragmentation. This study highlights the different uses of individual surrogate approaches and potential imbalances in conservation efforts among ecosystems and taxa, providing a reference for conservation management.