David Magney Environmental Consulting - California Native Plant ...

Comments on Draft EIR for Newhall Ranch Mission Village Development
DMEC Project No. 10-0181
1/3/2011
Page 16
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DMEC
The project applicant proposes to mitigate the SFVS loss by establishing a series of SFVS preserves that
they claim “ensures the long-term survival of spineflower populations on the project site and greater NRSP”
(Mission Village DEIR, page 4.3-163). These preserves are described in the Mission Village DEIR (pages
4.3-163 to 4.3-164): “The SCP [Spineflower Conservation Plan] establishes five San Fernando spineflower
preserves, four within the Newhall Ranch Specific Plan site and one within a portion of the Entrada planning
area. Of these preserves, the Airport Mesa Preserve is located on the Mission Village project site…As
described in the SCP, the five proposed preserves would encompass a total of 164.8 acres of land. The
preserve areas have been designed to accommodate natural spineflower population fluctuations and include
13.26 acres of occupied spineflower habitat and 152.6 acres of buffer area (unoccupied spineflower habitat).
In total, the five proposed preserves encompass 68.6 percent of the cumulative occupied spineflower habitat
within the SCP area… The Mission Village project includes the proposed Airport Mesa preserve; the
Mission Village Airport Mesa preserve as proposed would be larger than the Airport Mesa preserve
described in the SCP. The Mission Village Airport Mesa preserve would occupy 65.62 acres, including
5.28 acres of occupied spineflower habitat, 24.39 acres of core expansion area (unoccupied spineflower
habitat), and 35.96 acres of buffer area (unoccupied spineflower habitat) (see Figure 4.3-10, Airport Mesa
Preserve Core Population). It is unknown if any of the unoccupied open space included in the preserves is
suitable for spineflowers. The proposed Airport Mesa preserve was designed to conserve the areas of
greatest concentration of spineflower within the general Airport Mesa occurrence.”
A basic design assumption of the proposed SFVS preserve system seems to be that an essential “core” of
occupied SFVS habitat will be preserved that will adequately conserve the Newhall SFVS population.
References are made in the Mission Village DEIR to the “Airport Mesa Preserve Core Population” and that
the proposed Airport Mesa preserve will conserve the areas of “greatest concentration” of the SFVS
(Mission Village DEIR p. 4.3-163). In reference to the larger preserve system the SCP (page 112) states:
“This direct impact [take of approximately 6.36 acres (31%) of the 2002 through 2007 cumulative
spineflower occurrence area] will be fully mitigated, first by establishing a system of preserves to
protect the core occurrences of spineflower in the study area, and second by implementing
management and monitoring within an adaptive management framework to maintain or enhance the
protected spineflower occurrences within the five preserve areas.”
Based on the data presented, the SFVS appears to experience extreme population fluctuations over
relatively short periods of time across its entire known 30-acre range. The Las Virgenes (Ahmanson
Ranch) population fluctuated between 23,000 individuals in 1999, 1.46 million individuals in 2000, 1.8
million individuals in 2001, and 220,935 individuals in 2002 (SCP, page 14). The Newhall SFVS
population has experienced even more extreme population fluctuations than the Las Virgenes populations.
The Newhall RMDP-SCP Final EIS/EIR summarizes the known population trends for the SFVS on the
Newhall project site, including Mission Village (page 4.5-1,758),
“In 2003, surveys estimated populations of SFVS totaling 5,947,120 individuals occupying 16 acres.
In 2004, the total population of SFVS was estimated to be 558,388 individuals occupying 5.33 acres.
In 2005, the total population of SFVS was estimated to be 7,391,813 individuals occupying 11.45
acres. In 2006, the total population of SFVS was estimated to be 1,773,496 individuals occupying
8.49 acres. In 2007, the total population of SFVS was estimated to be 760 individuals occupying
0.12 acre.”
Reviewing the methodology used to determine SFVS population size, it is clear that the methods used are
not repeatable. That is, it would not pass a common statistical t-test. Obviously, it is not practicle, or really
possible, to physically count every SFVS plant. But to come up with a reasonably accurate estimate, strict