What does the future hold for Biodiversity Hotspots?

According to Myers et. al, (2000) [1a] and Hoffman et. al, (2016) [1b] there are currently 36 recognised Biodiversity Hotspots globally.

To qualify as a biodiversity hotspot, an area must meet two strict criteria:

• Contain at least 1,500 species of vascular plants found nowhere else on Earth (known as "endemic" species)
• Have lost at least 70 percent of its primary native vegetation

Unfortunately many of the hotspots shown here exceed these criteria.

Range shift is where a species may move its known ranges to track changes in its environment, (the basics of which are shown here). It is one way plants may adapt to a changing environment which may also include land use/land cover change, and habitat fragmentation. Species distribution modelling (aka ecological niche, or bioclimatic envelope modelling) has become a common way to predict where plants may disperse in future - so essentially seeing where these circles are moving over time. A lot of work exists on range shift to date, and this work specifically aims to develop the accuracy of future predictions, so conservationists and ecologists can prioritise how to conserve species and their habitat, and ultimately try to limit extinction risk as our climate and landscapes change.

The last thirty years of range shift research have led to an accumulation of studies, suggesting species are likely to alter their distributions globally in response to climate change [1c-10]. Anthropogenic change is heightening the effects of global change at local levels, resulting in multiple taxa being forced from their original habitats, with less opportunities to successfully adapt due to fragmentation and other alterations to the landscape mosaic. Many studies have modelled ways in which plants may respond to climatic change via range shifts, however, most have tended to focus on climate-only, correlative models, due to time or cost constraints.

Our aim was to conduct a global systematic map (similar to a systematic review but with a spatial focus) to synthesise plant range shift studies to date, and identify knowledge and geographical clusters and gaps to inform direction of ongoing ecological shift research on terrestrial plant species globally.

Stage 1: We used multiple databases to search for published peer-reviewed range shift studies.

Stage 2: We blind-screened the titles and abstracts of thousands of papers [11]. This took months!

Stage 3: After deciding which papers were relevant, we read them in full and collected many pieces of information about each article.

Stage 4: The creation of the systematic map where we collated the final studies together into an interactive web map using ArcGIS Pro and ArcGIS Dashboard.

When collating range shift articles, we used Scopus, Web of Science and Science Direct as the main source journal databases.

Using a combination of multi-query keyword terms (green diagram), over 13,000 papers were collated.

We then used Endnote reference managing software to remove nearly 6,000 duplicate articles.

During stage 2 we blind screened the remaining 7,336 studies, assessed for relevance to four main criteria using the R package "MetaGear" [12]:

• flora-only (e.g., fauna studies removed)
• terrestrial-only (e.g., marine studies removed)
• thirty year time slice (e.g., 1990-2020)
• predictive range shift research (e.g., studies looking back in time removed).

During this process, 6,987 studies that were not solely focused on plant range shift and did not conform to this criteria were removed.

Articles that passed screening were then "coded" to record the nature and techniques used within each study including scale, geographical location, plant major group, number of species, software, modelling parameters, and range-shift measurements.