Crop wild relatives of the United States require urgent conservation action

Abstract

The contributions of crop wild relatives (CWR) to food security depend on their conservation and accessibility for use. The United States contains a diverse native flora of CWR, including those of important cereal, fruit, nut, oil, pulse, root and tuber, and vegetable crops, which may be threatened in their natural habitats and underrepresented in plant conservation repositories. To determine conservation priorities for these plants, we developed a national inventory, compiled occurrence information, modeled potential distributions, and conducted threat assessments and conservation gap analyses for 600 native taxa. We found that 7.1% of the taxa may be critically endangered in their natural habitats, 50% may be endangered, and 28% may be vulnerable. We categorized 58.8% of the taxa as of urgent priority for further action, 37% as high priority, and 4.2% as medium priority. Major ex situ conservation gaps were identified for 93.3% of the wild relatives (categorized as urgent or high priority), with 83 taxa absent from conservation repositories, while 93.1% of the plants were equivalently prioritized for further habitat protection. Various taxonomic richness hotspots across the US represent focal regions for further conservation action. Related needs include facilitating greater access to and characterization of these cultural-genetic-natural resources and raising public awareness of their existence, value, and plight.

GapAnalysis: an R package to calculate conservation indicators using spatial information

“…Nevertheless, the user could refine these settings if interested in more stringent conservation standards. We also note that there are other open space lands, for example those managed by the U.S. Forest Service or Bureau of Land Management in the USA (aside from Wilderness Areas and a few other select designations), which are not listed in the WDPA due to being multi‐use and not primarily focused on biodiversity conservation (Khoury et al 2020). The WDPA may thus already be considered as relatively stringent about its definitions of protected areas (UNEP‐WCMC 2019) and might be seen by some land managers as underestimating habitat conservation.…”

“…The conservation gap analysis was built on methods developed over the past decade, first to measure the conservation status of taxa in repositories and to help guide further collecting efforts aimed at building more diverse ex situ collections (Ramírez‐Villegas et al 2010, Castañeda‐Álvarez et al 2016). Recently, the approach was adapted to measure representation within protected natural areas (Khoury et al 2019b, c2019c, d2019d, 2020, Lebeda et al 2019, Mezghani et al 2019, Myrans et al 2020). Such studies have most often been conducted across a range of species within a genus, although they have also been applied at national (Norton et al 2017, Khoury et al 2020) and global (Castañeda‐Álvarez et al 2016, Khoury et al 2019b) levels for specific groups of plants.…”

Harnessing Crop Wild Diversity for Climate Change Adaptation

“…In short, ML [138,[176][177][178][179] and deep learning approaches [133,170,180,181] promise assisting the conservation [102,[182][183][184], managing [185,186], prioritization [187][188][189], and introgression [190,191] of crop wild variation from genebanks (Figure 2). ML may be particularly useful in unexplored isolated pockets of diversity, which contain allelic variants otherwise eroded from modern genotypes [192,193].…”

Laying the groundwork for crop wild relative conservation in the United States

“…Although the advent of marker-and genomic-assisted breeding has facilitated the use of CWR for numerous crops, their diversity remains underutilized (5) and global efforts to collect and conserve CWR diversity remain a priority. In PNAS, Khoury et al (6) provide a foundational assessment of the conservation status of native CWR taxa in the United States.…”

“…Khoury et al (6) compiled a list of 600 CWR taxa native to the United States (including its territories), assigning each taxon to one of three gene pool groups (1A = wild progenitors, primary and secondary gene pools, rootstocks, and wild food sources; 1B = tertiary gene pool; and 1C = taxa in the same genus with undetermined relationships to the crop). Using locality data from over 800,000 herbarium records and 30,000 Gen-Bank collections, Khoury et al (6) modeled the distribution of each of these 600 taxa across North America. The composite distribution map highlights important CWR hotspots within the United States, including a large and taxonomically rich region stretching across the Midwest and Mid-Atlantic.…”