Search our Database


Methods

Data resources

1. Grass species nomenclature and descriptions

There are 12,093 grass species, but an estimated 62,047 grass names, which are mostly synonyms (duplicates for the same species). RBG Kew has compiled a complete list of all the grass synonyms in their GrassBase Synonomy Database. The GrassBase Online World Grass Flora also provides GrassPortal with information on plant morphological characters, such as leaf and seed size, and distribution information (based on expert opinion) for almost every species.

2. Herbarium archives

GBIF mapMany of the world’s herbaria have digitised large parts of their collections by scanning herbarium sheets. By linking these to information on species and collection locations, they have generated a large database of where species occur. A lot of this data has been assimilated by The Global Biodiversity Information Facility (GBIF), which currently contains over 4 million geo-referenced records for grasses.

3. Global environmental data

Environmental mapsThese include information on the key determinants of plant geographical distributions, including average climatic conditions, fire regime, soil conditions, and vegetation properties. By mapping the distribution of each grass onto these datasets, we are able to provide valuable information about the environmental requirements of every species.

4. Evolutionary relationships among grasses (phylogeny)

Evolutionary relationships in the ‘tree of life’ are inferred by comparing DNA sequences between species. Our project partner at the University of Lausanne has developed a new online system called GrassWeb. This reconstructs the evolutionary relationships for grasses as new DNA data become available.


Data integration

How it is integrated

These four types of data are integrated and linked within GrassPortal. The emphasis is on defining the geographical distribution and ecological characteristics of each grass species, and integrating with evolutionary information. This is achieved using these steps:

  • Define geographical distribution. Digitised herbarium archives are used to extract information about where each recognised species occurs;
  • Extract environmental conditions. These species occurrences are mapped onto environmental datasets to determine the range of conditions that each species experiences – i.e. its ecological characteristics;
  • Link distribution and environmental data with taxonomic and morphological trait data via GrassBase, and evolutionary relationships through GrassWeb.