CPC Plant Profile: Pink Sand-verbena
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Plant Profile

Pink Sand-verbena (Abronia umbellata ssp. breviflora)

Close-up view of the flowers and succulent leaves of Abronia umbellata ssp. breviflora. Photo Credit: Tom Kaye
Description
  • Global Rank: T2 - Imperiled
  • Legal Status: N/A
  • Family: Nyctaginaceae
  • State: BC, CA, OR, WA

Due to an ironic twist of fate, pink sandverbena was the first North American plant collected and described from west of the Mississippi. Pink sandverbena seeds were first collected at Monterey Bay, CA on a 1786 scientific expedition. The collector, Jean-Nicolas Collignon, was subsequently lost at sea with his ship. The seeds, however, had been sent back Paris on another ship, where they were grown in the Jardin des Plantes and named. Without active conservation efforts, pink sandverbena's ultimate fate may be as grim as that of the man who discovered it. Abronia umbellata ssp. breviflora was once found all along the Pacific coast, from northern California to British Columbia. Today it is limited to a few populations in northern California and Oregon. Long thought extinct in both Washington and British Columbia, two individuals were recently found on Vancouver Island that may be this species. Habitat destruction caused by human activity and exotic plant invasion does not solely impact this sandy beach dwelling species. The plight of the endangered western snowy plover (a native bird) appears correlated with the state of pink sandverbena. Both of these species require open sandy beaches, and evidence suggests that the snowy plover uses this sandverbena for forage and cover. It follows that efforts to conserve either of these species will be most effective if coordinated with each other. In 2000, two plants were found on Vancouver Island in British Columbia, Canada. The debate continues as to whether they are A. umbellata ssp. breviflora or a separate taxon, A. umbellata ssp. acutalata. If they are A. umbellata ssp. breviflora, then the range truly extends from northern California to Canada. If, however, they are identified as A. umbellata ssp. acutalata, two points become apparent: 1) there are only TWO remaining INDIVIDUALS of A. umbellata ssp. acutalata in the entire world and 2) the range of A. umbellata ssp. breviflora has been reduced to include only northern California and Oregon.

Conservation Actions:
Participating Institutions
Photos
Nomenclature
Taxon Abronia umbellata ssp. breviflora
Authority (Standl.) Munz
Family Nyctaginaceae
CPC Number 9
ITIS 19575
USDA ABUMB
Common Names pink sand verbena | pink sand-verbena
Associated Scientific Names Abronia umbellata ssp. breviflora | Abronia umbellata ssp. acutalata | Abronia umbellata var. breviflora | Abronia acutalata | Abronia breviflora | Abronia umbellata var. acutalata
Distribution Historically along Pacific Coast beaches from northern California to British Columbia. Presently extinct in Washington, and there is the possibility that only one population composed of two individua
State Rank
State State Rank
British Columbia S1
California SNR
Oregon S1
Washington SNR
Habitat

Pink sandverbena inhabits open sandy beaches, typically at or below the zone of driftwood accumulation and away from sand dominated by introduced European beachgrass (Ammophila arenaria) (Kaye 1997a, Kaye et al 1998).

Ecological Relationships

Abronia umbellata ssp. breviflora is an obligate outcrosser (Tillet, 1967). Its native insect pollinators require open dune habitats, and the destruction of dune habitats may lead to a decrease in pollinators and further decline for this rare species (Vrilakas 1988). Ripe fruits fall off when touched and seeds are dispersed by waves and strong winds. Most seedlings establish downwind from mature plants (Vrilakas 1988) Cold treatments in germination were largely unsuccessful. Instead, alternating warm temperatures was required. These results are consistent with natural conditions in A. umbellata ssp. breviflora habitat - the Pacific Coast generally receives a week or so of warm weather in early spring (Kaye et al 1998, Kaye 1999). Since populations are typically found at or below zone of driftwood accumulation, they are often obliterated by winter storms. Each spring, the population re-establishes from seeds that persist in the sand. In protected sandy areas, 3% of population over-winters and flowers the next year (Kaye et al., 1998). Natural populations sizes vary widely over time and space. For plants growing in more a static habitat, the observed drops in population size and reproductive output would be cause for grave concern. However, A. umbellata ssp. breviflora grows in a dynamic habitat characterized by winter storms that destroy old plants, but also create new habitat and disperse seeds. In areas outside monitoring plots, observations indicate that A. umbellata ssp. breviflora expands well onto recently deposited or disturbed substrates (Kaye 1999). Abronia umbellata ssp. breviflora numbers tend to decline with substrate age, especially after 3 years. Generally, other plant species increase in abundance and diversity (species richness) (Kaye 1999). Nutrient cycling in the soil affects these trends. In general fresh sand provided near optimal conditions for A. umbellata ssp. breviflora growth (Kaye 1999). After sand has been dredged, nitrogen increases with time, while potassium declines. On older substrates, nutrients are limiting (especially potassium) and competition for them is intense. While both increases in interspecific competition and decreases in soil fertility contribute to A. umbellata ssp. breviflora decline, is likely that competition has the stronger impact. On older substrates, adding fertilizer in the presence of competitors fertilizes the associated species as well, and competitors are able to establish and rapidly grow roots into pocket of nutrients below A. umbellata ssp. breviflora individuals (Kaye 1999). Frequent disturbances remove competing vegetation and may be required to maintain viable populations of pink sandverbena (Kaye 1999). Individuals within this species can be either annuals or short-lived perennials (Grenier 1991). Disturbances from winter storms play a complicated and important role in the life cycle of A. umbellata ssp. breviflora. These winter storms remove and deposit large amounts of sand, establish foredunes, and carry plants and seed out to the ocean. This disturbance often buries plants, preventing their short-term persistence; some restoration efforts have not been successful after the first year because of this phenomenon. However, winter storms also prevent other plants from establishing and outcompeting A. umbellata ssp. breviflora. This disturbance can be especially important in removing European beachgrass (Ammophila arenaria). Paradoxically, winter storm disturbances both hinder short-term survival of individuals and help the long-term persistence of populations and the species by creating new habitat (Kaye 2000). Genetic analyses of reintroduced populations indicates that the population size at the time of founding has a significant effect on the genetic diversity of that population. Genetic distance indicated limited divergence among most natural populations. It is likely that this limited divergence is due to a population bottleneck at some time in the species' history, or to high rates of migration between populations. This genetic similarity reveals that populations do not appear to be genetically adapted to one particular site, and consequently have more widespread reintroduction potential. Genetic contamination from reintroducing plants to natural populations is not much of an issue because all populations are so similar (McGlaughlin, 2000). Scientists currently debate whether the plants found in British Columbia are another, otherwise extinct taxon: Abronia umbellata ssp acutalata. If they indeed are distinct, then there are only two remaining individuals of Abronia umbellata ssp acutalata in the world.

Updates

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Andre Clemente 03/20/2020

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Pollinators
Common Name Name in Text Association Type Source
Bees
Honey bees Apis mellifera Floral Visitor Link
Bumble bees Bombus pennsylvanicus Floral Visitor Link
Butterflies & Moths
Skippers Hesperiidae Confirmed Pollinator Link
Noctuid moths Noctuidae Confirmed Pollinator Link
Sphinx moths Sphingidae Confirmed Pollinator Link
Flies
Syrphid flies Syrphid flies Confirmed Pollinator Link

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