Examples and applied use

Gap analyses were carried out to contribute towards recommendations for the in situ and ex situ conservation of priority CWR in Norway.


  • CWR checklist: created from the Crop Wild Relative Catalogue for Europe and the Mediterranean (Kell et al. 2005, 2008) and updated and harmonized with the Flora of Norway (Lid and Lid 2005).
  • CWR priority list: obtained by applying the following criteria to the CWR checklist: CWR within the same genera as crops of high economic value as given by gross production value (current million US$) for global production value (2013), within Europe (2013) and within Norway (2013) (from FAOSTAT); CWR present in Annex 1 of the ITPGRFA; CWR highlighted as being of specific importance to Norwegian research, culture and environment; taxa within the Harlan and de Wet inventory (Vincent et al. 2013); native taxa only, according to the flora of Norway (Lid and Lid 2005).
  • Distribution data were gathered from GBIF for the priority taxa and the following analyses were undertaken:

    • In situ analysis: taxon richness and sampling bias maps were created; the Complementa tool from the CAPFITOGEN tool set (Parra-Quijano et al. 2016) was used to perform a grid cell and a protected area (PA) complementarity analysis to identify potential PAs for in situ conservation; the number of populations conserved within the complementary networks was identified; predicted distribution maps were created for each priority CWR using the MaxEnt algorithm; the predicted distribution maps were then compared to the observed distribution to determine how many taxa were predicted to be conserved within the PA network; an ELC map was created and zones in complementary networks were identified to determine the level of ecogeographic diversity conserved.
    • Ex situ analysis: the CAPFITOGEN tool Representa was used to identify gaps in the collection of priority CWR taxa; ELC zones were identified which were under-represented in the ex situ collections of taxa.

Main results

  • Checklist: 2538 CWR.
  • Priority list: 204 CWR.
  • In situ analysis: the most taxa rich areas are in the south-east of Norway with the north containing the lowest taxa richness. Ten percent of taxa are not found within a PA; the complementarity analysis produced a network of 19 grid cells (10 km2) that contain all 201 priority taxa; the PA complementarity analysis identified 23 existing PAs that contain 181 taxa (the remaining 20 taxa are not found within a PA); the PA complementarity network covers 17 of the 27 ELC zones and contains an average of 23% of ecogeographic diversity per taxon.
  • Ex situ analysis: 177 priority CWR are not conserved ex situ and these should be targeted for ex situ collection; ELC zones 3 and 17 are the highest priority to target for collection of taxa.

Source: Phillips et al. (2016)

An ex situ gap analysis was carried out for 73 of the closest wild relatives of potato (Solanum section Petota), including wild potatoes in the primary and secondary gene pools as well as any distant relatives in the thirtiary gene pool that have confimed or potential uses in crop breeding. The aim of this analysis was to establish priorities for further collecting to fill important gaps in germplasm collections.

Germplasm data were obtained from repositories easy to access, namely: EURISCO, GRIN and CIP’s biomart portal. Other species occurrence data and additional germplasm accessions passport data were gathered from various online databases and via communications with data managers, including GBIF, CRIA, SINGER, CPNWH, the Atlas of Guatemalan Crop Wild Relatives (Azurdia et al. 2011), the PBI Solanum—a worldwide treatment, LAC biosafety, as well as from literature (e.g. Spooner et al. 2014), and herbaria (i.e. E, K, L, NY, MA, PH, RB and US). The occurrence data collated and used in this analysis are available here. Potential distribution models were obtained for each species using MaxEnt (Phillips et al. 2006) based on a set of 19 bioclimatic variables derived from the WorldClim database (Hijmans et al. 2005) at a resolution of 2.5 arc-minutes (approx. 5 km at the equator). Performance of models was assessed based on three criteria: (i) the 5-fold average Area Under the Test ROC Curve (ATAUC), (ii) the standard deviation of the ATAUC for the 5 different folds, and (iii) the proportion of potential distribution where the standard deviation is greater than 0.15 (ASD15). A suitable model had to meet the following conditions: ATAUC >0.7, STAUC <0.15 and ASD15 <10% (Ramírez-Villegas et al. 2010). For those species where a suitable model was not obtained (either due to lack of data or low performance of the ensemble model), a convex hull (polygon surrounding the outermost georeferenced points) was prepared.

The gap analysis methodology used was that of Maxted et al. (2008) and of Ramírez-Villegas et al. (2010). Three metrics were used to prioritize CWR for collecting: a Sampling Representativeness Score (SRS) (compared the number of germplasm accessions to the total number of samples and provided an overview of the sufficiency of accessions per species), a Geographic Representativeness Score (GRS) [compared the distribution models with the geographic distribution of existing germplasm accession collecting sites, which was estimated by creating circular buffers of 50 km (CA50) around each site where the accession was collected (Hijmans et al. 2001), and which assessed the geographic coverage of germplasm collections], an Ecosystem Representativeness Score (ERS) [compared the number of ecosystems currently represented in ex situ collections with the total number of ecosystems distributed within the distribution models of each taxon, using a world terrestrial ecoregions map (Olson et al. 2001)]. Equal weight was given to these three metrics and an average was calculated to obtain a Final Priority Score (FPS). Collecting priorities were then categorized as follows: high priority species (HPS) when FPS ≤3, or when ten or less accessions were recorded in germplasm collections; medium-priority species (MPS) when 3< FPS ≥5; low priority species (LPS) when 5< FPS ≥7.5; and ‘no further collecting of germplasm required’ (NFCR) when 7.5< FPS ≥10. The gap analysis was performed using R v2.15.1 (R Core Team 2014) and various packages (see the paper for more details).

Priority areas for collecting ex situ gaps identified above were prepared for each species by subtracting the existing germplasm CA50 buffers from the potential distribution models. For those species where a niche model was not produced, CA50 buffers were prepared around all presence records and germplasm CA50 buffers were subtracted from the CA50 buffers of all presence records. Collecting gap maps for all high priority species were then obtained using the ‘Zonal Statistics’ tool in ArcMap 10.1 which produced a species richness map of further collecting per country of occurrence.

A total of 32 species (43.8%) were assigned high priority for further collecting, most of them located in Peru, the geographic centre of diversity of potato wild relatives. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, and only three species were considered to be sufficiently represented.

Source: Castañeda-Álvarez et al. (2015)

Wild relative of potatoes here pictured in Peru. (Photo: Eve Allen)

Individual CWR taxon gap analysis—Aegilops spp.

Existing geo-referenced passport data associated with 22 Aegilops species were used to identify gaps in current conservation and to develop a global conservation strategy for the genus. Sources of taxonomic, ecological, geographic and conservation information included: ICARDA, EURISCO, GRIN and SINGER datasets. The occurrence database contained 9,866 unique geo-referenced observations collected between 1932 and 2004. Distribution maps and predicted distribution maps, using climatic models, were obtained and compared using ArcGIS and DIVA-GIS to carry out individual taxon conservation gap analyses. Species priorities were assigned based on ex situ conservation status, with highest priority given to Ae. bicornis, Ae. comosa, Ae. juvenalis, Ae. kotschyi, Ae. peregrina, Ae. sharonensis, Ae. speltoides, Ae. uniaristata and Ae. vavilovii. Future ex situ collections were recommended in Cyprus, Egypt, Greece, Iran, Israel, Libya, Spain, Syria, Tajikistan, Tunisia, Turkey, Turkmenistan and Uzbekistan.

In addition, patterns of species richness were obtained and five complementary regions of Aegilops diversity were identified in west Syria and north Lebanon, central Israel, northwest Turkey, Turkmenistan and south France for in situ conservation. Within these areas, 16 IUCN-designated PA were identified as potential sites to establish genetic reserves. However, the most important identified area (on the Syrian/Lebanese border) does not coincide with any existing formal PA, thus, a novel PA would need to be established.

Source: Maxted et al. (2008b)

The Interactive Toolkit for Crop Wild Relative Conservation Planning was developed within the framework of the SADC CWR project www.cropwildrelatives.org/sadc-cwr-project (2014-2016),
which was co-funded by the European Union and implemented through ACP-EU Co-operation Programme in Science and Technology (S&T II) by the African, Caribbean and Pacific (ACP) Group of States.
Grant agreement no FED/2013/330-210.