Water hyacinth occurrence and satellite derived covariates for South Africa

Table S1. Feature descriptions, associated units, temporal coverages, and data sources of the features considered to investigate the likely drivers of water hyacinth occurrence. All explanatory variables were downloaded at a 30 m spatial resolution. Those variables that were only available at a coarser spatial resolution (> 30 m) were automatically resampled to 30 m using bilinear interpolation within Google Earth Engine.

Variable

Units

Temporal coverage

Source

Number of consecutive nights with less than 10 degrees Celsius

days

2013

MODIS LST- night

Area of waterbody

m2

2013

(Singh et al., 2020)

Median river width at mean discharge

m

1984 - 2018

Global River Width from Landsat (GRWL) (Allen & Pavelsky, 2018)

*Area of aquatic vegetation

m2

2013

(Singh et al., 2020)

*Minimum Temperature in the coldest month between1970 and1990

°C

1970 - 2000

WorldClim

Connectivity- upstream and downstream river count

river count

2000

WWF hydrosheds (Grill et al., 2019)

*Water seasonality- number of months water is present

month count

**1984 - 2019

JRC GSW (Pekel et al., 2016)

*Total precipitation

mm

**1958 - 2021

TerraClimate

*Distance to nearest coastline

m

2009

NOAA (https://oceancolor.gsfc.nasa.gov/docs/distfromcoast/)

*Distance to roads

m

1979 - 2010

Global Road Infrastructure Project (GRIP) (Meijer et al., 2018)

Elevation

m

2000

NASADEM

*Continuous Heat Insolation Load Index (0=cool, 255=warm). Surrogate for effects of shading and topographic insolation

0-255

2006 - 2011

SRTM, (Theobald et al., 2015)

*Global Human Modification (1= high modification)

0 - 1

2016

(Kennedy et al., 2019)

*Topographic diversity- Surrogate for the variety of temperature and moisture conditions available to species as local habitats

-1323 - 8.81

2006 - 2011

SRTM, (Theobald et al., 2015)

Frost duration - Median duration of frost

day count

2007

(Schulze & Maharaj, 2007)

Number of days below 0°C (0-365)

day count

**2000 - present

MODIS- LST, night temperature

Number of days below 10°C (0-365)

day count

**2000 - present

MODIS- LST, night temperature

*South African National Land Cover (73 class)

km2

2013 - 2014

GeoTerraimage

*Mean Annual Runoff

mm/year

2005

Strategic Water Source Areas (SWSA)

*Broad (10) class Landcover

% (cover fraction)

2015

Copernicus Global Land Landcover Layers (CGLS-100)(Buchhorn et al., 2020)

*Flood hazard with a 10-year return period

water depth (m)

2016

Joint Research Commission (Dottori et al., 2016)

Riparian soil nitrogen (5km buffer)

g/kg

1905 - 2016

Soil grids

Riparian soil ph (5km buffer)

pH

1905 - 2016

Soil grids

*Riparian soil carbon (5km buffer)

g/kg

1905 - 2016

Soil grids

*Stream Power Index (SPI)

-1 - 1

1987 - 2017

GeoMorpho90 GeoMorphometric layers (Amatulli et al., 2020)

*Relative wealth index

-1 - 1

2001 - 2019

Facebook (https://dataforgood.fb.com/tools/relative-wealth-index/)

13 iSDA Soil layers (includes *total nitrogen, etc.)

various

2013 - 2019

(Hengl et al., 2021)

*Mean wind speed for a 10-year period

m/s

2008 - 2017

Global wind atlas

* Included in final model, ** Multi-temporal data - 2013 or temporally closest data was selected