DOI: 10.5061/dryad.2jm63xt26
title: Climate change modelling indicates extensive range contractions for a scarce southern African endemic and minimal protected area network within its future climatically suitable range

description: The Black Harrier (Circus maurus) is listed as Endangered by the IUCN and
 is an endemic, range-restricted habitat specialist within southern Africa.
 Our study aimed to assess the current and potential future changes in the
 distribution of the Black Harrier, as well as to quantify the most
 suitable areas within both the “breeding range” (i.e., areas used for
 nesting) and the “all-year-round range” (i.e., areas used by Black
 Harriers during breeding and non-breeding periods). Using tracking data of
 13 tagged adults and 307 nest locations collected from 2000-2015, we
 implemented a Species Distribution Modelling workflow, making use of a
 data-driven process of variable selection and model optimization. Model
 optimization included hyper-parameter tuning, which is the process of
 finding the optimal settings for model parameters to improve predictive
 performance. Additionally, we used General Circulation Models and three
 Shared Socioeconomic Pathways to assess the potential impact of climate
 change on the geographical distribution of the Black Harrier. Our study
 shows that a disproportionately low percentage (32%) of the area currently
 climatically suitable for the Black Harrier hosts suitable breeding
 habitat for the species. Climate change modelling projects extensive range
 contractions (up to 83%) of both Black Harrier breeding and all-year-round
 ranges by 2061-2080. Core areas of the projected future range are in the
 coastal, Overberg, and mountain Fynbos/Renosterveld regions of the Western
 Cape province of South Africa. Furthermore, only ca. 20% and 10% of Black
 Harrier’s breeding and all-year-round ranges, respectively, fall within
 Protected Areas (PAs). Prioritising, protecting, and managing the
 remaining habitat patches within the projected future range by including
 them within PA networks, will be critical to promote the persistence of
 the Black Harrier.
description: # Climate change modelling indicates extensive range contractions for a
 scarce southern African endemic and minimal protected area network within
 its future climatically suitable range Dataset DOI:
 [10.5061/dryad.2jm63xt26](10.5061/dryad.2jm63xt26) ## Description of the
 data and file structure This dataset contains occurrence records for the
 Endangered Black Harrier (*Circus maurus*) collected between 2014 and
 2020, aggregated and spatially denatured in line with Category 2
 biodiversity data protection protocols. Original point locality records
 were generalized to a spatial resolution of 10 km and converted to a
 raster (GeoTIFF) format representing species observation counts per 10 km
 grid cell. The dataset is provided in GeoTIFF format, which is commonly
 used for storing spatial data. The main data file and several auxiliary
 files are included: | **Filename** | **Description** | |
 :-------------------------------------------------------------------- |
 :------------------------------------------------------------------------------------------------------------------------------- | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tif` | Main data file. A raster (GeoTIFF) representing the number of Black Harrier sightings per 10 km grid cell. | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tfw` | A world file containing georeferencing information that helps GIS software position the `.tif` correctly on the Earth’s surface. | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tif.aux.xml` | A metadata file generated by GIS software that stores auxiliary information (e.g., symbology, statistics) about the raster. | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tif.ovr` | A pyramid overview file, used to improve rendering speed when zooming in/out within GIS applications. | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tif.vat.dbf` | A value attribute table in DBF format that stores pixel value attributes (e.g., count of records per grid cell). | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tif.vat.cpg` | Specifies the character encoding (usually UTF-8) for the `.dbf` attribute table. | | `BirdLasserData_BlackHarrier_2014_2020_DenaturedtoCounts.tif.xml` | A standard XML metadata file, compatible with ArcGIS, describing spatial reference, origin, extent, and additional metadata. | The dataset provides a spatial summary of Black Harrier distribution based on vetted citizen science records. Raw point-level data are not publicly shared due to species sensitivity and are available upon reasonable request under appropriate licensing conditions. ## Code/software * Viewing: The dataset can be opened using GIS software such as QGIS (free and open-source) or ArcGIS Pro. * Analysis or conversion: Can be converted to CSV or other tabular formats using R, Python, or GDAL-based tools ## Access information The denatured dataset is archived on Dryad (see DOI above). Original citizen science records are also accessible (in raw or generalized form) via: * BirdLasser * eBird * SABAP2 Raw data is not publicly distributed due to species sensitivity but may be shared upon request under suitable licensing and ethical review.