Authors: Jory Griffith and Nina Obiar
Review status: In review
The CSIRO Biodiversity Habitat Index (BHI) directly assess the progress of Goal A within the Kunming-Montreal Global Biodiversity Framework (GBF) to increase the area of national ecosystems by 2050 through maintaining, enhancing, and restoring the integrity, connectivity, resilience of all ecosystems.
BHI estimates the proportion of species expected to persist (i.e. avoid extinction) within and given spatial reporting unit (Hoskins et al., 2020). More specifically, BHI estimates the level of species diversity expected to be retained within any given spatial reporting unit (e.g., a country, a broad ecosystem type, or the entire planet) as a function of the unit’s area, connectivity and integrity of natural ecosystems across that unit (Harwood, et al., 2022).
Results for the indicator can either be expressed as 1. the ‘effective proportion of habitat’ remaining within the unit – adjusting for the effects of the condition and functional connectivity of habitat, and of spatial variation in the species composition of ecological communities (beta diversity); or 2. the effective proportion of habitat that can be translated, through standard species-area analysis, into a prediction of the proportion of species expected to persist (i.e. avoid extinction) over the long term.
This pipeline calculates a weighted geometric mean of the BERI indicator over a region of interest. The code to calculate the weighted mean was adapted from the "Calculating weighted geometric means of CSIRO BILBI indicator" script on the CSIRO data access portal
BHI directly addresses three of the key ecosystem attributes in Goal A of the GBF, which include area, integrity, and connetivity, along with the combined effect of these attributes on species diversity.
The BHI is used to monitor and report past-to-present trends in the expected persistence of species diversity by repeatedly recalculating the indicator using best-available mapping of ecosystem condition or integrity observed at multiple points in time, e.g., for different years. A wide variety of data sources can be used for this purpose, spanning spatial scales from global to subnational, and including data assembled by countries for deriving ecosystem condition accounts under the UN SEEA Ecosystem Accounting framework.
The BHI can also serve as a leading indicator for assessing the contribution that proposed or implemented area-based actions are expected to make towards enhancing the present capacity of ecosystems to retain species diversity, thereby providing a stronger foundation for strategic prioritisation of such actions by member countries.
There are no data or API keys required for this analysis.
BON in a Box contains a pipeline to calculate the BHI indicator for a given area of interest. The pipeline has the following user inputs:
Bounding Box and CRS: the user must select a bounding box and coordinate reference system (CRS) to be used for the analysis. This can be done by using the chooser to either select a country and/or region, or enter or draw a custom bounding box. Then, an appropriate CRS can be selected from the corresponding drop-down menu.
Start date: this input is optional. The user can select a start date for time series layers, in the format YYYY or YYYY-MM-DD. To perform the analysis on all available years, the user should leave this input blank. The layers start at 2020-01-01.
End date: this input is optional. The user can select an end date for the time series layers, in the format YYYY or YYYY-MM-DD. To perform the analysis on all available years, the user should leave this input blank. The layers end at 2024-12-31.
Temporal resolution: this input is optional. The user can select a temporal resolution for the query of STAC items by date, in the format ("P", time interval, and time unit, e.g. "P1Y" is yearly, "P1M" is monthly, and "P1D" is daily). If the temporal resolution is coarser than the temporal resolution of the time series, the layers will be aggregated with the aggregation method chosen below. The user should not put in a temporal resolution finer than that of the layer. The BHI dataset has a temporal resoltion of 5 years from 2000 until 2020 and then a layer for 2024. The user should leave this input blank if no start and end date was selected.
Spatial resolution: the user can select the spatial resolution of the rasters. This must be in the same units as the coordinate reference system (meters for projected reference systems and degrees for reference systems in lat-long). To use the original spatial resolution of the layers, the user should leave this input blank. If the spatial resolution is left blank, the CRS selected must be EPSG:4326.
Resampling method: the user must select a resampling method to be used when the analysis requires rescaling to a new spatial resolution and/or reprojecting of the raster layers. See gdalwarp for a description. This input will be ignored if there is no need for resampling.
Aggregation method: the user must select a method to aggregate items when layers are combined over time, e.g. if a courser temporal resolution is chosen. This input will be ignored if there is no need for aggregation (the temporal resolution of the original layers is selected).
This step returns the polygon for the country/region/area of interest. If a country/region was selected, it pulls the country/region polygon using the GeoBoundaries API, and outputs as a geopackage, projected in the crs of interest. If the user inputs a custom bounding box, it will return a polygon made from that bounding box.
This step first extracts the CSIRO Biodiversity Habitat Index (BHI) layers, then the CSIRO denominator layers, from collections on the GEO BON Spatio Temporal Asset Catalog. The layers are in EPSG:4326 and 30 arc-second resolution but the user can specify other coordinate references systems and spatial resolutions. The CSIRO denominator layers are use to calculate the weighted geometric mean of the CSIRO BHI layers.
This step calculates the weighted arithmetic mean for the BHI layers to calculate the summary statistics over the area of interest.
Raster layers of indicator for each year: raster files of the BHI layers in geotiff format.
BHI summary: yearly weighted geometric mean of the BHI in the area of interest. The value ranges from 0 to 1, where a higher value indicates that a large proportion of the habitat remains in good condition and is well-connected, leading to a high expectation of species persistence. A lower value indicates that a significant proportion of the original habitat has been lost, degraded, or fragmented, which puts biodiversity at risk.
Time series plot: plot of the geometric mean of the BHI over time in the area of interest.
Country: the country of interest, if selected.
Region: the region of interest, if selected.
Example output available soon.
Harwood, Tom; Ware, Chris; Hoskins, Andrew; Ferrier, Simon; Bush, Alex; Golebiewski, Maciej; Hill, Samantha; Ota, Noboru; Perry, Justin; Purvis, Andy; & Williams, Kristen (2022): BHI v2: Biodiversity Habitat Index: 30s global time series. v1. CSIRO. Data Collection. doi: https://doi.org/10.25919/tt2t-h452
Hoskins, Andrew J.; Harwood, Thomas D.; Ware, Chris; Williams, Kristen J.; Perry, Justin J.; Ota, Noburu; Croft, Jim R.; Yeates, David K.; Jetz, Walter; Golebiewski, Maciej; Purvis, Andy; Ferrier, Simon. (2020). BILBI: Supporting global biodiversity assessment through high-resolution macroecological modelling. Environmental Modelling & Software 132:104806. doi: https://doi.org/10.1016/j.envsoft.2020.104806