Habitat and population monitoring for Chloropyron maritimum ssp. palustre and Limonium californicum on the Coos Bay North Spit
In 2017 the estimated number of Chloropyron maritimum ssp. palustre plants on the Coos Bay North Spit land managed by the Coos Bay District of the Bureau of Land Management is ~570,000, an increase from 2016 values.
In 2017 the population of Limonium californicum decreased from those observed in 2016, and is estimated to be ~564,000.
Habitat mapping from 2011-2017 has shown a shift towards more Limonium californicum dominant habitat types, and an increase in the non-native Juncus gerardii in recent years.
In 2017 the estimated number of Chloropyron maritimum ssp. palustre plants on the Coos Bay North Spit land managed by the Coos Bay District of the Bureau of Land Management is 570,000 (300,000 in the protected area and 270,000 in the unprotected area). This is higher than estimates in 2016 when only 376,000 were counted (289,000 in the protected and 87,000 in the unprotected).
In 2017 the population of Limonium californicum decreased from those observed in 2016, and is estimated to be 564,000 with 468,000 and 97,000 in the protected and unprotected area, respectively. In 2016 it was estimated that the population of L. californicum was 653,000 with 532,000 in the protected and 120,000 in the unprotected area.
Habitat mapping since 2011 has tracked the general decrease in Chloropyron maritimum ssp. palustre dominant habitat (designated ‘CF’ for ‘Chloropyron Flat’) in the protected area. In 2011, 293m2 of ‘CF’ habitat was mapped, in 2017, only 23m2 were mapped. Similar decreases were observed in the unprotected area, with cover decreasing from 1,268m2 in 2012 to 77m2 in 2017. The long-term decreases in the cover of ‘CF’ habitat coincides with increases in the cover of Limonium californicum habitats in both the protected and unprotected portions of the occupied habitat.
The relatively small portion of the Coos Bay North Spit occupied with these rare species is found in a long, narrow strip of appropriate habitat in a dynamic system. This narrow strip of land (700m long with a maximum width of 50m) lies in a precarious location along the shoreline where minor fluctuations in sea level (due to natural or manmade activities), could cause significant loss of habitat.