Seed Zone Mapper

A Mapping and Planning Tool for Plant Material Development, Gene Conservation and Native Plant Restoration



SEED ZONE = an area within which plant materials can be transferred with little risk of being poorly adapted to their new location.

This site allows end-users to view and acquire data on seed zones for use in plant material development, gene conservation and native plant restoration activities. Users can also evaluate seed zones in relation to other map services and wildland threats published by WWETAC such as climate change projections or wildfire risk. Client applications range in functionality from a simple geobrowser (requires only a web browser) to ArcGIS ArcMap, a full-feature GIS software platform that allows the user to integrate their own data and create map layouts.

This mapping application is part of a family of Wildland Threat Mapping (WTM) applications developed by WWETAC to portray the spatial interactions of wildland threats and high value resources that occur in wildlands. Visit WWETAC's WTM page for a collection of these mapping applications.

Tree_dna_jpgWTM Seed Zone GeoBrowser

The SeedZone GeoBrowser is an interactive 2D map that displays in your internet web browser - no software installation is required. To navigate around the map, Left-click and drag your mouse to pan, use your mouse wheel or the slider control in the upper left to zoom, and Shift-Left click to drag to define a new map extent. Click on the 'Tools' pane on the right side to access tools such as zoom to layer, zoom to a user-defined point, and identify.



Seed Zone Map Layers

Deploying well adapted and ecologically appropriate plant materials is a core component of a successful restoration project. However, restoration practitioners are often forced to deploy plant species on the landscape for which no seed transfer guidelines have been established through genetic research. So what are practitioners to do when no seed transfer guidelines have been established for a species of interest? We have developed generalized provisional seed zones that can be applied to any plant species to help guide seed movement. These seed zones are based on the intersection of high resolution climatic data. Climate data was obtained from the PRISM Climate Group and included raster files for mean monthly minimum and maximum temperature and annual precipitation based on climate normals for the period 1981-2010 with an 800m x 800m cell size. Data was imported into ArcMap version 10 (ESRI, Redlands, CA) for all analyses. Minimum winter temperature was determined as the minimum value per cell from December through February and was classified into 5oF (2.8oC) bands that ranged from <10o - >55o F (-12.2o - 12.8oC). These intervals were chosen to reflect the familiar temperature bands used in the USDA plant hardiness zone map (Cathey 1990, arborday.org) ). Aridity was calculated as the annual heat:moisture index (AH:M) following the method of Hamann and Wang (2005) as mean annual temperature plus 15 C (to obtain positive values) divided by mean annual precipitation in meters (mean annual temperature = (mean maximum temperature + mean minimum temperature) / 2). AH:M was then divided into six discrete classes (<2, 2-3, 3-6, 6-12, 12-30, and >30) where higher values indicate more arid environments. The Union function of ArcMap was used to intersect the minimum winter temperature with the AH:M layer to create unique climatically delineated (temperature-aridity) provisional seed zones. The intersection of these two variables, each classified into discrete bands, results in the delineation of 64 provisional seed zones for the continental United States. These zones represent areas of relative climatic similarity, and movement of seed within these zones should help to minimize maladaptation. Superimposing Omernick’s level III ecoregions over these seed zones helps to distinguish areas that are similar climatically yet different ecologically. These provisional seed zones should be considered a starting point as guidelines for seed transfer, and should be utilized in conjunction with appropriate species specific information as well as local knowledge of microsite differences.


Edited Provisional Seed Zones - In these maps, zones have been combined based on local knowledge and to reduce the total number of zones by merging zones with limited areas into adjacent zones.

Great Basin Edited Seed Zones - Provisional seed zones for grasses and forbs for the Great Basin area have been edited based on expert local knowledge. Several seed zones that covered only very small geographic areas were merged, and the zones in the Northern Great Basin and Snake River Plain Level III ecoregion were combined. Zones were combined based on temperature and/or precipitation. For example, all zones in temperature bands 60 degrees F. or lower were combined, and all zones <10" annual precipitation were combined based on whether the temperature band was above or below 80 degrees F. These edited provisional seed zones for the Northern and Central Great Basin areas can be downloaded by clicking on the link below.

Empirical Seed Zones from Common Garden Studies - For the common garden approach to developing seed zones, methods are outlined by Campbell (1986), Rehfeldt (1986) and St Clair et al. (2005) for conifer species. Similar techniques have been used by Erickson et al. (2004) for blue wildrye and for mountain brome (Johnson et al. 2010). First, a comprehensive collection of germplasm is completed to represent the diverse geographic and climatic features of the targeted region. Second, plants from collection locations across the region are evaluated in common gardens for production, morphology, phenology, and physiological traits. And third, statistical analyses are completed to develop regression models that link genetic variation across the landscape with collection location environments. Regression models are projected and mapped to delineate seed zones for studies species and geographic areas.

Following are details on seed zone coverages based on empirical common garden datasets:


Blue wildrye (Elymus glaucus): Blue Mountains Ecoregion (Oregon, WA): Source-related phenotypic variance was investigated in a common garden study of populations of Elymus glaucus Buckley (blue wildrye) from the Blue Mountain Ecological Province of northeastern Oregon and adjoining Washington. The primary objective of this study was to assess geographic patterns of potentially adaptive differentiation in this self-fertile allotetraploid grass, and use this information to develop a framework for guiding seed movement and preserving adaptive patterns of genetic variation in ongoing restoration work. Progeny of 188 families were grown for 3 years under two moisture treatments and measured for a wide range of traits involving growth, morphology, fecundity, and phenology. Variation among seed sources was analyzed in relation to physiographic and climatic trends, and to various spatial stratifications such as ecoregions, watersheds, edaphic classifications, etc. Principal component (PC) analysis extracted four primary PCs that together accounted for 67% of the variance in measured traits. Regression and cluster analyses revealed predominantly ecotypic or stepped-clinal distribution of genetic variation. Three distinct geographic groups of locations accounted for over 84% of the variation in PC-1 and PC-2 scores; group differences were best described by longitude and ecoregion. Clinal variation in PC-3 and PC-4 scores was present in the largest geographic group. Four geographic subdivisions were proposed for delimiting E. glaucus seed transfer in the Blue Mountains. (PDF Document)

Mountain Brome (Bromus carinatus): Blue Mountains Ecoregion (Oregon, WA): Plants from 148 Blue Mountain seed source locations were evaluated in common-garden studies at two contrasting test sites. Data on phenology, morphology, and production were collected over two growing seasons. Plant traits varied significantly and were frequently correlated with annual precipitation and annual maximum temperature at seed source locations (P < 0.05). Plants from warmer locations generally had higher dry matter production, longer leaves, wider crowns, denser foliage, and greater plant height than those from cooler locations. Regression models of environmental variables with the first two principal components (PC 1 and PC 2) explained 46% and 40% of the total variation, respectively. Maps of PC 1 and PC 2 generally corresponded to elevation, temperature, and precipitation gradients. The regression models developed from PC 1 and PC 2 and environmental variableswere used to map seed transfer zones. (PDF Document)

Prairie junegrass (Koelaria macrantha): (coming soon)

Bluebunch wheatgrass (Pseudoroegneria spicata):

A genecological approach was used to explore genetic variation in adaptive traits in Pseudoroegneria spicata, a key restoration grass, in the intermountain western United States. Common garden experiments were established at three contrasting sites with seedlings from two maternal parents from each of 114 populations along with five commercial releases commonly used in restoration. Traits associated with size, flowering phenology, and leaf width varied considerably among populations and were moderately correlated with the climates of the seed sources. Pseudoroegneria spicata populations from warm, arid source environments were smaller with earlier phenology and had relatively narrow leaves than those from mild climates with cool summers, warm winters, low seasonal temperature differentials, high precipitation, and low aridity. Later phenology was generally associated with populations from colder climates. Releases were larger and more fecund than most of the native ecotypes, but were similar to native populations near their source of origin. Differences among native populations associated with source climates that are logical for survival, growth, and reproduction indicate that genetic variation across the landscape is adaptive and should be considered during restoration. Results were used to delineate seed transfer zones and population movement guidelines to ensure adapted plant materials for restoration activities.

Sandberg's bluegrass (Poa secunda): (coming soon)

Indian ricegrass (Achnatherum hymenoides): Indian ricegrass –Colorado Plateau and Great Basin: Indian ricegrass (Achnatherum hymenoides [Roemer & J.A. Schultes] Barkworth) is a widely distributed, highly desirable native species in desert ecosystems in the western United States. Yet there are no studies linking genetic variation in Indian ricegrass with climate across major areas of its natural distribution. In this study, seeds from 106 collection locations from the southwestern United States were established in common gardens and four phenological traits (Phen; such as blooming date), six production traits (Pro; such as dry weight), and eight morphology traits (Morph; such as leaf dimensions) were measured in 2007 and 2008. Analyses of variance revealed that all basic garden traits differed among source locations (P,0.01), indicating widespread genetic variation. Within Phen, Pro, and Morph categories, canonical correlation was completed between basic garden traits and source location temperature and precipitation. This resulted in six significant (P,0.01) canonical variates (Phen 1, Pro 1 and 2, and Morph 1, 2, and 3) representing each category of traits. Linear correlations (r.60.25, P,0.01) consistently linked monthly temperature at collection locations with Phen 1, Pro 1, and Morph 1. For precipitation, however, correlations were more dependent on month, with the strongest correlations during the spring developmental period. Using regression models between traits and climate, a map with 12 seed zones was developed representing much of the southwestern United States. This generally distinguished genetic variation between cooler and warmer regions, usually separating more northern, higher elevation areas from more southern, lower elevation areas. The correspondence between climate and genetic variation suggested climate-driven differences in natural selection, likely leading to adaptation. The seed zone map is recommended to guide and broaden germplasm collection and utilization for Indian ricegrass restoration.

Tapertip onion (Allium acuminatum):

The choice of germplasm is critical for sustainable restoration, yet seed transfer guidelines are lacking for all but a few herbaceous species. Seed transfer zones based on genetic variability and climate were developed using tapertip onion (Allium acuminatum Hook.) collected in the U.S. Great Basin and surrounding areas. Bulbs from 53 locations were established at two common garden sites and morphological (such as leaf and scape dimensions), phenological (such as bolting date and flowering), and production traits (such as emergence and seeds per plant) were measured. Differences among source locations for plant traits within both common gardens were strong (P<0.001) indicating genetic variation. Principal component 1 (PC 1) for phenological traits, with R2=0.59, and PC 1 for production traits, with R2 =0.65, were consistently correlated with annual, maximum, minimum, and average temperature, annual precipitation, and frost free days at source locations (P<0.05). Regression of PC 1 phenology and PC 1 production scores with source location climates resulted in models with R2 values of 0.73 and 0.52, respectively. Using GIS, maps of these models were overlaid to develop proposed seed zones to guide the choice of germplasm for conservation and restoration of Tapertip onion across the collection region.

Oceanspray (Holodiscus discolor): Western Oregon and Washington: This common garden study was implemented to characterize the variability in growth and phenological traits relative to climatic and geographic variables of 39 Holodiscus discolor (Pursh) Maxim. accessions from locations throughout the Pacific Northwest, U.S.A. Principal component analysis of 12 growth and phenological traits explained 48.2% of the observed variability in the first principal component (PC-1). With multiple regressions, PC-1 was compared to environmental values at each source location. Regression analysis identified a four-variable model containing elevation, minimum January temperature, maximum October temperature, and February precipitation that explained 86% of the variability in PC-1 (r2 ¼ 0.86, p < 0.0001). Spatial analysis using this regression model identified patterns of genetic diversity within the Pacific Northwest that can help guide germplasm selection (i.e., seed collections) for restoration and revegetation activities.



Download Provisional Seed Zone GIS data:

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Provisional Seed Zones for all Species

CONUS

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Download Edited Provisional Seed Zone GIS data:

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Edited Provisional Seed Zones

Great Basin

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Download Empirical (Common Garden Studies) Seed Zone GIS data:

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Blue wildrye (Elymus glaucus)

Blue Mountains Ecoregion (Oregon, WA)

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Mountain Brome (Bromus carinatus)

Blue Mountains Ecoregion (Oregon, WA)

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Prairie junegrass (Koelaria macrantha)

Columbia Basin and Great Basin

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Bluebunch wheatgrass (Pseudoroegneria spicata)

Western US

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Sandberg's bluegrass (Poa secunda)

Western US

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Tapertip onion (Allium acuminatum)

Western US

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Indian ricegrass (Achnatherum hymenoides)

Western US

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Oceanspray (Holodiscus discolor)

Western US

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References:

Bower, A., St. Clair J.B., and V.J. Erickson. 2010. Provisional seed zones for native plants. http://www.fs.fed.us/wildflowers/nativeplantmaterials/rightmaterials.shtml

Cathey, H.M. 1990. USDA Plant hardiness zone map. Washington, D.C.: U.S. Department of Agriculture. USDA miscellaneous publication No. 1475. Available at http://www.usna.usda.gov/Hardzone/ushzmap.html.

Campbell, R. K. 1986. Mapped genetic variation of Douglas-fir to guide seed transfer in southwest Oregon. Silvae Genet. 35:85-96.

Erickson, V.J., Mandel, N.L. and F.C Sorenson. 2004. Landscape patterns of phenotypic variation and population structuring in a selfing grass, Elymus glaucus (blue wildrye). Can. J. Bot. 82:1776-1789.

Johnson, G.R., F.C Sorenson, J.B. St Clair and R.C. Cronn. 2004. Pacific northwest forest tree seed zones - A template for native plants?. Native Plants 5:131-140.

Johnson, G.R , L. Stritch, P. Olwell, S. Lambert, M.E. Horning, and R. Cronn. 2010. What are the best seed sources for ecosystem restoration on BLM and USFS lands? Native Plants 11: 117-131

Johnson, R.C., V.J. Erickson, N.L. Mandel, J.B. St Clair, and K.W. Vance-Borland. 2010. Mapping genetic variation and seed zones for Bromus carinatus in the Blue Mountains of Eastern Oregon, U.S.A. Botany.

Omernik, J.M. 1987. Ecoregions of the conterminous United States. Ann. Assoc. Amer. Geogr. 77(1): 118-125. doi:10.1111/j.1467-8306.1987.tb00149.x.