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“It
is probably a healthy exercise, when considering the extinction of
species in this age, to remember that many thousands of life forms have
ceased to exist from wholly natural causes -- dinosaurs spring
invariably to mind. And
further that some organisms -- especially primitive forms, which, as it
were, are ‘past their prime’ -- will pass into oblivion, both
without human assistance and in spite of it.” - from The
Birdwatcher’s Companion, page 229, authored by Christopher Leahy of
the Massachusetts Audubon Society, 1982.) |
| Vertical
Mulching - A high priority recovery need for the federally-listed desert
tortoise and other sensitive species occurring within the California
Desert is the restoration of unauthorized routes, or road reclamation
(refer to West Mojave Route Designation, Ord Mountain Pilot Unit,
Biological Resource Screening Components; Bureau of Land Management
1997). Such restoration allows for the protection of large contiguous
blocks of habitat that are relatively unencumbered by vehicle use
impacts and related activities. Restoring unauthorized routes would
significantly reduce identified habitat fragmentation occurring within
designated tortoise critical habitat units and yield tremendous positive
benefits affecting recovery of this species. Of the 22 major threats to
the tortoise identified in recent research, ten would be significantly
reduced by restoring unauthorized roads and trails, including the
following: fire, off highway vehicle recreation, animal collection,
garbage and litter, handling and manipulation, invasive weeds, noise,
vandalism, predation (by ravens and similar subsidized predators), and
non off-highway vehicle recreation. The Barstow Field Office of the
Bureau of Land Management is currently seeking support among potential
cooperators to use “desert tortoise habitat compensation” funds for
road and trail restoration. Such funds are occasionally generated,
pursuant to guidelines in BLM’s Desert Tortoise Rangewide Plan, when
habitat-impacting projects are approved within the range of the tortoise
that cannot be fully mitigated on-site. In the past, these “habitat
compensation” funds have typically been used to acquire private
inholdings within designated tortoise critical habitat units. Recently,
however, the Barstow Field Office determined that compensation funds
generated by several large-scale projects would enable cooperating
agencies to protect/enhance a much larger amount of tortoise habitat if
these funds were used for route restoration, rather than habitat
acquisition. Both methods of offsite habitat compensation are necessary
for long-term recovery of the desert tortoise and other sensitive
species in certain critical habitat units, and these options should be
carefully evaluated on a case-by-case basis. To accomplish both tortoise
habitat restoration and route designation objectives in critical habitat
units, BLM staff have developed a reclamation strategy commonly referred
to as “vertical mulching.” This technique involves the placement of
structure (live vegetation, rocks, dead shrubs and “snags,”
bunch-grasses, and various woody material) within the confines of the
closed roadway surface, both on the ground surface and in a vertical
manner, designed to conform with adjacent vegetation and terrain. Use of
this technique is further described below. Discussion: Lessons learned
by BLM over past decades have shown that route designation cannot be
effectively implemented by simply installing red carsonite “closed to
vehicle use” signs on or adjacent to unauthorized routes of travel.
Efforts must include encouraging vehicle travel on designated open
routes, and making designated closed routes literally disappear into the
landscape. To begin this “disappearing act,” decompaction and
mulching techniques must be applied to closed routes, extending at least
to the visual horizon, especially where the closed routes intersect with
other routes. The Barstow Field Office has demonstrated that
unauthorized roads and trails can be economically restored through use
of vertical mulching techniques. These techniques involve placement of
boulders and organic structure, such as live/dead and down vegetation,
within the disturbed soil portion of affected roadbeds. Only vegetation,
rock and woody structure native to the immediate closed route vicinities
are used. The estimated cost for restoring tortoise habitat using this
technique is $500 per acre, using current technology. The target
restoration areas consist of roads and trails that facilitate a variety
of anthropogenic impacts to designated desert tortoise critical habitat.
The specified collection and installation of mulching material occurs
under the supervision of a qualified natural resource specialist,
archeologist, biologist or technician, to ensure a minimization of
impacts to biological or cultural resources. Areas adjacent to where
route closure/rehabilitation is planned may occasionally be used to
gather dead vertical mulching material, in a manner designed to avoid
causing local dead and down habitat loss, yet also accomplish
restoration objectives. In no circumstances are shrubs that shade animal
burrows or that are located adjacent to cultural resources, removed for
use as mulching material. However, live and dead vegetation from the
immediate region, salvaged from land clearing or road maintenance
operations, may occasionally be used as mulching material in such
restoration projects. Memorandums of understanding developed between
land management agencies and local transportation departments, regarding
salvage and storage of native material for this application, can
facilitate large-scale projects. The use of pitting, ripping, or other
scarification techniques within the confines of route or roadbed soil
disturbance is sometimes necessary for rapid site recovery. Such
scarification is done with hand-tools or through the use of heavy
equipment and machinery (toothed rake, pitter, or similar device pulled
by a tractor). After scarification, the live or dead vegetation is
placed in a vertical fashion within the confines of route or roadbed
soil disturbance, in a manner designed to conform to adjacent terrain
and vegetation. The Barstow Field Office is able to restore Mojave
Desert habitats for about $500 per acre, due to relationships and
agreements it has in place with the California Conservation Corps and
other local young adult labor groups. Under an existing agreement, the
California Conservation Corps will match BLM contributed project funds
on a dollar for dollar basis. As a consequence, funds generated by large
habitat-disturbing projects could also qualify for matching by the state
of California, in the form of matching labor funds available via the use
of the California Conservation Corps. Conclusion: Vertical mulching can
be an economical technique for restoring unauthorized roads and trails
in desert tortoise and other sensitive species’ habitats. In some
circumstances it may provide much more “bang for the buck” when
compared to traditional forms of offsite compensation. Its application
in selected areas of the California Desert will reduce anthropogenic
impacts to the listed desert tortoise, contributing significantly to the
recovery of this threatened species. References: Bureau of Land
Management (BLM). 1997. West Mojave route designation, Ord Mountain
pilot unit, biological resource screening components. California Desert
District BLM Office, Riverside, California. http://www.blm.gov/nstc/resourcenotes/rn16.html
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