assumption that ecosystem recovery will follow (Hesp and Hilton, this volume).
There is a need to better integrate the physical and biological components of
restoration monitoring, particularly in the light of global climate change (Psuty and
Silveira 2010).
This chapter presents a case study of the restoration at the Lanphere and
Ma-le’l Dunes in Humboldt Bay National Wildlife Refuge, California, USA.
These areas are managed with the goals of conserving and restoring globally rare
dune habitats, supporting the recovery of endangered dune plants, and promoting
long-term viability of ecosystems (USFWS 2009). Restoration goals for these
projects were articulated in the context of ecosystem processes, with measurable
objectives and monitoring focused on biotic variables such as vegetation cover,
species diversity, and endangered plant recovery. Dune morphological terminology in this chapter follows Hesp (2000). Plant nomenclature follows the Flora of
North America (FNAEC 1993).
10.2 Dune system
The Lanphere and adjoining Ma-le’l Dunes units encompass 327 ha located at
40.88°N on the upper end of the North Spit of Humboldt Bay in northern
California (Fig. 10.1). Littoral drift is dominated by northern, storm-driven
transport in the winter, and by southern, wind/wave-driven transport in the summer
(Winkelman et al. 1999). Net northern transport occurs during the El Niño events
of the Pacific Decadal Oscillation (Moffat and Nichol 2011). The majority of
sediments feeding the system originate from the Eel River, 28 km to the south,
which drains 9,540 km
2 and is estimated to deliver approximately 1.8 million m
3
of sand annually (Patsch and Griggs 2007). The site is exposed to some of the most
severe wave energy in the US, with predominant west–northwest swells from
October through April (Costa and Glatzel 2002). The prevailing wind direction is
north to northwest from spring through autumn, reversing to south to southeast in
winter (Puffer 1998). Winds are strongest in April and May, reaching daily
averages of 12.9 kph, and peak gusts up to 97 kph. An average of 96.7 cm of
rainfall falls primarily between the months of October and May (Puffer 1998).
Surveyor charts from 1870 provide a record of the condition of the dune system
prior to subsequent extensive modification of the area by EuroAmericans. The
upper North Spit in 1870 consisted of two episodes of Holocene dune transgression, one older and stabilized by forest and a second overtaking the forest
(Fig. 10.2). Reactivation of the forested dunes is hypothesized to be the result of
the Cascadia subduction zone earthquake that occurred in 1700 (Atwater et al.
2005). Megaquakes along the subduction boundary occur at 100–1,000-year
intervals and are tied to repeated dune activation at other dune sites in the Pacific
Northwest (Wiedemann and Pickart 1996; Atwater et al. 1995). Relative sea level
rise along the North Spit from 1977 to 2006 was 4.73 ± 1.58 mm per year, well
above the global average (Moffat and Nichol 2011). Interseismic land level
160
A. J. Pickart
There is a need to better integrate the physical and biological components of
restoration monitoring, particularly in the light of global climate change (Psuty and
Silveira 2010).
This chapter presents a case study of the restoration at the Lanphere and
Ma-le’l Dunes in Humboldt Bay National Wildlife Refuge, California, USA.
These areas are managed with the goals of conserving and restoring globally rare
dune habitats, supporting the recovery of endangered dune plants, and promoting
long-term viability of ecosystems (USFWS 2009). Restoration goals for these
projects were articulated in the context of ecosystem processes, with measurable
objectives and monitoring focused on biotic variables such as vegetation cover,
species diversity, and endangered plant recovery. Dune morphological terminology in this chapter follows Hesp (2000). Plant nomenclature follows the Flora of
North America (FNAEC 1993).
10.2 Dune system
The Lanphere and adjoining Ma-le’l Dunes units encompass 327 ha located at
40.88°N on the upper end of the North Spit of Humboldt Bay in northern
California (Fig. 10.1). Littoral drift is dominated by northern, storm-driven
transport in the winter, and by southern, wind/wave-driven transport in the summer
(Winkelman et al. 1999). Net northern transport occurs during the El Niño events
of the Pacific Decadal Oscillation (Moffat and Nichol 2011). The majority of
sediments feeding the system originate from the Eel River, 28 km to the south,
which drains 9,540 km
2 and is estimated to deliver approximately 1.8 million m
3
of sand annually (Patsch and Griggs 2007). The site is exposed to some of the most
severe wave energy in the US, with predominant west–northwest swells from
October through April (Costa and Glatzel 2002). The prevailing wind direction is
north to northwest from spring through autumn, reversing to south to southeast in
winter (Puffer 1998). Winds are strongest in April and May, reaching daily
averages of 12.9 kph, and peak gusts up to 97 kph. An average of 96.7 cm of
rainfall falls primarily between the months of October and May (Puffer 1998).
Surveyor charts from 1870 provide a record of the condition of the dune system
prior to subsequent extensive modification of the area by EuroAmericans. The
upper North Spit in 1870 consisted of two episodes of Holocene dune transgression, one older and stabilized by forest and a second overtaking the forest
(Fig. 10.2). Reactivation of the forested dunes is hypothesized to be the result of
the Cascadia subduction zone earthquake that occurred in 1700 (Atwater et al.
2005). Megaquakes along the subduction boundary occur at 100–1,000-year
intervals and are tied to repeated dune activation at other dune sites in the Pacific
Northwest (Wiedemann and Pickart 1996; Atwater et al. 1995). Relative sea level
rise along the North Spit from 1977 to 2006 was 4.73 ± 1.58 mm per year, well
above the global average (Moffat and Nichol 2011). Interseismic land level
160
A. J. Pickart