Chapters 1 - U.S. Fish and Wildlife Service

Chapter 2
2.5 Management Concerns/Opportunities
In addition to the issues raised during the public scoping process, the planning team, with input
from other partners, also identified several challenges, threats, and/or opportunities that will likely
affect Refuge management over the next 15 years and beyond. These concerns include a number
of factors (e.g., climate change, sea level rise, subsidence, and the inadvertent release of non-native
terrestrial and marine species into the Refuge environment) that cannot be altered by actions
undertaken by Refuge staff; instead Refuge management actions must be evaluated from time to
time to adapt to these changing conditions. Other concerns that can be addressed through
enhanced Refuge management actions include mammalian and avian predation of listed species
and the need to increase the availability of upland refugia for marsh birds and shorebirds during
periods of high tide. All of these challenges, which are described in greater detail below, were
considered during the development of the alternatives presented in Chapter 3 of this document.
Climate Change/Sea Level Rise
Increasing carbon dioxide and other greenhouse gas emissions from anthropogenic sources
have undeniably altered the temperature over the last century. Such temperature changes can
have different consequences worldwide from sea-level rise to greater meteorological
fluctuations. The Service recognizes that a changing climate will impact natural resources on
refuges and has been charged by the Secretary of the Interior (Secretarial Order 3289) to
include climate change in our planning processes. Anticipated impacts may include: species
range shifts, species extinctions, phenological changes, and increases in primary productivity.
This challenge is especially important at the Seal Beach NWR because a sea level rise of only a
few inches could have significant adverse effects on the quality of the cordgrass-dominated salt
marsh habitat and other intertidal habitats present within the Refuge. Intertidal habitats
could slowly convert to subtidal habitat, eliminating habitat essential to the light-footed clapper
rail, Belding’s savannah sparrow, and other intertidal-dependent species. At present there are
only limited areas of upland habitat within the Refuge that could be made available for
conversion to intertidal habitat as sea level rises. The effects of climate change and sea level
rise on Refuge resources, facilities, and management activities are critical components of all
Refuge management decisions.
Addressing the effects of climate change and sea level rise will require coordination among a
variety of agencies at all levels of government. To adequately address issues such as
identifying opportunities for accommodating new intertidal habitats along the southern
California coast that will support the diversity and abundance of intertidal-dependent species
currently present will involve a significant commitment of time and resources. The coastal
refuges of southern California (i.e., Tijuana Slough, San Diego Bay, and Seal Beach NWRs), as
well as other protected coastal habitats along the southern California coast, will be important
components of a future strategy for ensuring the adequate availability of intertidal habitats to
support listed species, migratory birds, and estuarine fisheries. Additional discussion of
climate change and sea level rise is provided in Chapter 4.
Subsidence
Both subsidence and rebound of the marsh plain within Anaheim Bay has been documented in
studies conducted between 1968 and 1994. Based on the results of these studies, there appears
to be a net reduction in the elevation of the marsh plain between 1968 and 1994 of between 0.18
to 0.4 feet across the marsh. The reasons for subsidence in this area is likely related to a
combination of oil extraction activities in the area and historic extraction of groundwater for
2-4 Seal Beach National Wildlife Refuge