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Climate Change Refugia for Biodiversity in the Klamath-Siskiyou Ecoregion

  • Geos Institute
  • Florida Institute for Conservation Science

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The Klamath-Siskiyou Ecoregion has been a refuge for species during past climate change events, but current anthropogenic stressors are likely compromising its effectiveness as a refugium for this century's projected changes. Reducing non-climate stressors and securing protection for large, complex landscapes are important long-term actions to alleviate climate change impacts on biodiversity. Equally important is the immediate protection of a network of climate change microrefugia, particularly old growth and intact forests on north-facing slopes and in canyon bottoms, lower- and middle-elevations, wetter coastal mountains, and along elevational gradients. Such areas provide local opportunities for vulnerable species to persist within the ecoregion. We identify a provisional set of 22 highest-priority and 40 high-priority microrefugia that occur mostly outside of existing protected areas and along wetter and lower elevations of the ecoregion. Proposed reserve designs, if fully implemented, would capture most of the recommended microrefugia, although we found 11 important gaps. Most of the region's biodiversity, endemic species, and species vulnerable to climate change are invertebrates, non-vascular plants, and fungi that are largely restricted to persistently cool and moist late-successional forests. Opportunities for climate change response for vulnerable taxa will necessarily be local due to a limited capacity of many species to move to new habitat, even over relatively small distances where land use practices create inhospitable conditions. The ecoregion's distinctive and endemic serpentine-substrate flora also is at risk and possible refugia are sites that will retain wet soil conditions, such as seeps and bogs.
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Climate Change Refugia for Biodiversity in the Klamath-Siskiyou Ecoregion
Author(s) :David Olson, Dominick A. DellaSala, Reed F. Noss, James R. Strittholt, Jamie Kass, Marni E.
Koopman and Thomas F. Allnutt
Source: Natural Areas Journal, 32(1):65-74. 2012.
Published By: Natural Areas Association
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Volume 32 (1), 2012 Natural Areas Journal 65
Natural Areas Journal 32:65–74
Climate Change
Refugia for
Biodiversity in the
David Olson1
1 Conservation Earth Consulting
4234 McFarlane Ave.
Burbank, CA 91505
Dominick A. DellaSala2,6
Reed F. Noss3
James R. Strittholt4
Jamie Kass
Marni E. Koopman2
Thomas F. Allnutt5
2 Geos Institute
84 Fourth Street
Ashland, OR 97520
3 Department of Biology
University of Central Florida
4000 Central Florida Blvd.
Orlando, FL 32816-2368
4 Conservation Biology Institute
260 SW Madison Avenue, Suite 106
Corvallis, OR 97333
5 Department of Environmental Science,
Policy and Management
130 Mulford Hall
University of California
Berkeley, CA 94720-3114
6 Corresponding author:
ABSTRACT: The Klamath-Siskiyou Ecoregion has been a refuge for species during past climate change
events, but current anthropogenic stressors are likely compromising its effectiveness as a refugium for this
century’s projected changes. Reducing non-climate stressors and securing protection for large, complex
landscapes are important long-term actions to alleviate climate change impacts on biodiversity. Equally
important is the immediate protection of a network of climate change microrefugia, particularly old
growth and intact forests on north-facing slopes and in canyon bottoms, lower- and middle-elevations,
wetter coastal mountains, and along elevational gradients. Such areas provide local opportunities for
vulnerable species to persist within the ecoregion. We identify a provisional set of 22 highest-priority and
40 high-priority microrefugia that occur mostly outside of existing protected areas and along wetter and
lower elevations of the ecoregion. Proposed reserve designs, if fully implemented, would capture most of
the recommended microrefugia, although we found 11 important gaps. Most of the region’s biodiversity,
endemic species, and species vulnerable to climate change are invertebrates, non-vascular plants, and
fungi that are largely restricted to persistently cool and moist late-successional forests. Opportunities for
climate change response for vulnerable taxa will necessarily be local due to a limited capacity of many
species to move to new habitat, even over relatively small distances where land use practices create
inhospitable conditions. The ecoregion’s distinctive and endemic serpentine-substrate flora also is at risk
and possible refugia are sites that will retain wet soil conditions, such as seeps and bogs.
Index terms: climate change, ecoregion, Klamath-Siskiyou, microrefugia, refugia
The Klamath-Siskyou Ecoregion (KSE)
contains globally important biodiver-
sity–only five other temperate forests
regions are as diverse or home to as many
endemic species and ancient lineages (e.g.,
Caucasus, Southwestern China, Southeast-
ern United States, Coastal Plain/Southern
Appalachians, Valdivia rainforests of Chile
and Argentina; Olson et al. 2001; Tecklin
et al. 2011). The special location (latitude
and coastal proximity), rugged terrain, cli-
matic stability, and complexity of soils and
microclimates have allowed the region to
act as a refuge from past climatic changes
for species and natural communities requir-
ing cool and moist conditions (Whittaker
1960, 1961; Stebbins and Major 1965;
Wagner 1997; Coleman and Kruckeberg
1999; Sawyer 2007).
One might expect that the KSE will con-
tinue to function well as a climate change
refugium as human-caused climate change
progresses. However, cumulative land use
impacts combined with projected climate
change could have a profound impact on
the ecoregion’s species and ecosystems.
In the KSE, over a century of land use
activities (e.g., logging, mining, livestock
grazing, damming of rivers, mining, and
human-caused alterations of fire) have
resulted in loss or degradation of mesic
habitats (DellaSala et al. 1999) that may
have previously functioned as refugia over
millennia. Impacts include loss of contigu-
ous habitat along intact elevational and
other environmental gradients that may
facilitate climate-related shifts in natural
communities and loss and degradation of
most of the mature and old-growth for-
ests (e.g., only about 28% of the historic
old-growth forests remain; Strittholt et
al. 2006), particularly mesic lowland and
mid-elevation habitats (Staus et al. 2002).
Increasing prevalence of invasive plants
and pathogens facilitated by road building
and land use practices poses an additional
threat to native species and communities
(DellaSala et al. 1999).
The existing protected area system (i.e.,
National and State Parks, Wilderness Areas,
National Monuments, Botanical Areas) is
inadequate for ensuring the persistence
of most of the ecoregion’s vulnerable
biodiversity (DellaSala et al. 1999; Noss
et al. 1999; Carroll et al. 2010). Existing
reserves largely protect higher-elevation
communities, while the lower-elevation
reserves are limited in their geographic
extent, thereby missing many distinct
lowland species assemblages and areas
that may act as potential microrefugia.
We define microrefugia as sites with cool
and moist conditions conducive to the
persistence of species vulnerable to climate
change. Thus, our conservation strategy for
the KSE builds on prior reserve propos-
als (Noss et al. 1999; Carroll et al. 2010;
KS Wild 2010; Siskiyou Project 2010) by
66 Natural Areas Journal Volume 32 (1), 2012
adding microrefugia and other elements
to create a reserve design more robust to
anticipated increases in temperature and
changes in precipitation over the century
(Koopman et al. 2009).
Fundamental to the development of a robust
conservation design are three core-plan-
ning elements: (1) reduction of non-cli-
mate stressors; (2) protection of complex
landscapes; and (3) protection of climate
change microrefugia. Taken together, they
are the foundation for guiding reserve
design and conservation implementation
in the KSE.
Reduction of Non-Climate Stressors
Reducing non-climate stressors across the
landscape, such as curtailing or greatly
reducing logging and road building, is
the single most important action that land
managers can take to help the regional
biota and ecosystems persist in the face
of a changing climate. The release from
stressors should be strategically targeted to
critical core habitats, old-growth forest mi-
crorefugia, and adaptation corridors along
environmental gradients (sensu, Olson et
al. 2009). For example, if large complex
landscapes were off-limits to logging
(only about 13% of the region is strictly
protected; DellaSala et al. 1999), and all
of the predicted local climate refugia,
old-growth forests, and priority corridors
in the KSE (e.g., Noss et al. 1999) were
effectively protected, this would have a
much more positive effect for biodiversity
than if most of the area released from log-
ging was in highly degraded, mid-elevation
production forests. The release of strategic
areas from land use stressors would need
to allow maturing forests to once again
dominate the landscape.
Protection of Complex Landscapes
Securing a high level of protection and
undertaking ecologically based restoration
in degraded areas is important, as well as
protection of large, complex landscapes
with diverse terrains, soils, microclimates
and other environmental gradients. In
particular, low and mid-elevation habitats
in higher precipitation areas (e.g., along
the coast) will provide multiple local op-
portunities for persistence of vulnerable
species. In the KSE, conservation groups
have identified two areas having these
characteristics: a 243,000 ha land bridge
known as the proposed Siskiyou Crest
National Monument (considered a climate
refuge) in southwest Oregon and northern
California (KS Wild 2010) and a ~445,000
ha proposed Siskiyou Wild Rivers National
Salmon and Botanical Area in southwest
Oregon, a hotspot of serpentine flora and
wild rivers (Siskiyou Project 2010; Figure
1). Protection of these areas will greatly im-
prove the chances for persistence of a large
portion of the ecoregion’s terrestrial and
freshwater biota even if we are uncertain
of the magnitude, timing, and distribution
of changes in temperature and precipitation
at sub-ecoregional scales (e.g., Murphy et
al. 2004; Moilanen et al. 2006).
Figure 1. Climate change vulnerability zones (coastal, transition, dry, high elevation) of the Klamath-
Siskiyou Ecoregion, southwest Oregon and northern California, used in the analysis to inform priority
site selection for conservation action.
Volume 32 (1), 2012 Natural Areas Journal 67
Protection of Climate Change
In order to maintain pockets of habitat
for climate-vulnerable species, conserva-
tion attention should be aimed at securing
microrefugia that may uniquely provide
opportunities for many species to persist
and are particularly threatened due to ongo-
ing habitat degradation and rapid warming.
The importance of microrefugia for the
long-term persistence of species that are
sensitive to climate change is increasingly
being recognized (Noss 2001; Loarie et
al. 2008, 2009; Rull 2009, 2010; Ashcroft
2010; Dobrowski et al. 2010). In temper-
ate regions, terrain positions and habitat
types that maintain persistent cool and
moist conditions favorable for effective
microrefugia are increasingly well defined
(e.g., Dobrowski et al. 2010).
Because of the rapid speed of climate
change (Loarie et al. 2008, 2009), includ-
ing warmer temperatures (Koopman et al.
2009) and diminishment of fog (Johnstone
and Dawson 2010) in the KSE, opportu-
nities for long-term persistence for many
species will be local, likely within a scale
of a few kilometers, from the location of
present populations. Many species will be
unable to shift rapidly enough to areas with
more favorable conditions. Moreover, most
of KSE’s species, distinctive (endemic)
species, and those vulnerable to climate
change are mesophilic, old-growth forest
specialists, largely lesser known taxa (by
the public) such as invertebrates, fungi,
bryophytes, and other non-vascular plants
(Olson 1992; Lattin 1993; Olson 2010;
Vicente 2010). The majority of these taxa
cannot cross even small distances of terrain
with unfavorable conditions (e.g., light,
hot, and dry; Frest and Johannes 1993;
Niwa and Peck 2002). Thus, protection
and restoration of microrefugia around
extant populations is essential for the long-
term perpetuation of the vast majority of
the KSE biota. The ecoregion’s endemic
serpentine flora (Kruckeberg 1984; Har-
rison et al. 2006; Sawyer 2007) is also
highly vulnerable to projected increases
in temperature and drying (Damschen et
al. 2010) and some taxa may only persist
within persistently wet pockets and seeps
surrounded by late-seral forests (collec-
tively mature and old growth) that can act
as climatic buffers.
Many extant microrefugia and the species
and populations they contain may be lost
or degraded within a few decades due to
ongoing exploitation of forests and land-
scapes within the ecoregion, particularly
at low and mid elevations, slow pace of
change that is typical for forest manage-
ment and protected areas practices, and
rapid changes being documented in climate
and natural communities (Damschen et al.
2010). Although the long-term efficacy of
microrefugia is still uncertain (Carroll et al.
2010; Dobrowski et al. 2010), especially
if they remain embedded within largely
degraded landscapes, it remains a prudent,
bet-hedging strategy in the face of uncer-
tainty to protect a network of microrefugia
representative of the ecoregion’s distinct
species assemblages.
Microrefugia Site Features
Site features for effective microrefugia in
the KSE include north-facing slopes, valley
bottoms and steep canyons, and sinks and
basins because they are shadier and exist
where cool air predictably pools in the
lower sites (Dobrowski et al. 2010). Such
sites are likely to have climate states and
trends that are decoupled from regional
averages, a requisite for microrefugia to
persist through time. Forests with a north-
east- and north-facing aspect also have a
lower frequency of wildfires that can alter
the capacity of habitats to retain cool and
moist conditions (Taylor and Skinner 2003;
Alexander et al. 2006).
Habitat types that will function well as
microrefugia for climate change-sensitive
species include late-seral forests, although
the greater litter, understory vegetation,
and canopy complexity and biomass of
old-growth forests (> 150 yrs) makes them
superior at retaining moisture (Chen et al.
1999). Late-seral forests that occur in areas
with high-precipitation and fog, such as
in coastal mountains (Loarie et al. 2008;
Ackerly et al. 2010; Carroll et al. 2010)
or other areas that experience significant
orographic precipitation (e.g., > 1143 mm
annual precipitation) will, on average, be
better able to retain more moisture and
cooler conditions than lower precipita-
tion zones. This is due to more abundant
water and greater canopy, understory
vegetation, litter biomass, and complexity
in these forests. Late-seral forests within
watersheds are also superior to degraded,
logged, roaded, and burned vegetation for
providing cooler stream temperatures and
robust aquatic ecosystems (Strittholt and
DellaSala 2001; Staus et al. 2010).
Storm tracks, regional rainfall, and fog pat-
terns may shift due to climate change (Det-
tinger et al. 1998; Salathé et al. 2008; Mote
and Salathé 2009; Johnstone and Dawson
2010), but coastal mountains are expected
to continue to receive Pacific storms first
and much of the region’s rainfall into the
future (Daly et al. 1994). Certainly, vul-
nerable species and communities occur at
higher elevations and in drier areas towards
the eastern portion of the ecoregion, but the
vast majority of distinctive biodiversity for
the ecoregion (all taxa being considered)
occur within the coastal fog and transition
zones (Figure 1; Sawyer 2007). The latter
zone includes more mesic forests along
the Siskiyou Crest (Oregon/California),
Eddy Mountains (northwest California),
Scott Mountains (northwest California),
and Yolla Bolly’s (southern limits of the
ecoregion) that are relatively far from
the coast. In general, the larger and more
round a forest block, the greater the core
habitat area–internal habitat that does not
experience the drying effects of forest edges
(Chen et al. 1999).
Natural communities and vulnerable spe-
cies within refugia also willhave improved
opportunities for persistence if microrefu-
gia span broad elevational gradients, allow-
ing populations to shift locally over time
through contiguous mesic habitat (Noss
2001; Olson et al. 2009). North-South cor-
ridors of contiguous natural vegetation are
important for many reasons, such as dis-
persing vertebrates, but a swiftly changing
climate will likely limit the ability of most
slowly dispersing organisms to move long
distances northwards over generations.
68 Natural Areas Journal Volume 32 (1), 2012
Until patterns of local endemism and
beta-diversity for speciose groups, such
as invertebrates, are better known, prox-
ies for mapping distinct assemblages can
be used to assess how well a network of
microrefugia provides refuge to KSE’s
diverse biota. Useful proxies for assess-
ing representation of biodiversity within
and among microrefugia are mesorefugia.
We define mesorefugia as large areas that
contain nested clusters of microrefugia
with similar species assemblages that have
functioned as a refugium over millennia
(Rull [2009] defines mesorefugia as larger
regions to which temperate biotas shifted
during glacial maxima). Mesorefugia
typically occur at the scale of mountain
ranges or watershed complexes along
coastlines, and their location along river
canyons (e.g., Rogue, Umpqua, Klamath,
Eel rivers) may facilitate future expansions
and enable vagile species to move more
freely across landscapes. Careful selection
and protection of microrefugia of varying
species assemblages (e.g., plant association
groups) within and among mesorefugia
would help to achieve representation goals
while maximizing the number of extant
species that will persist in emerging novel
Mesorefugia analyses complement exist-
ing representation analyses that focus on
vegetation types and other communities
derived from combinations of biophysi-
cal features (e.g., Vance-Borland 1999;
Staus et al. 2001; Carroll et al. 2010). As
such, candidate mesorefugia (Figure 2)
for the KSE were initially identified from
large-scale biophysical features and loca-
tions that predict effective refugia–coastal
mountains with complex topography and
areas of high precipitation (Loarie et al.
2009; Rull 2009, 2010; Dobrowski 2010).
Areas with concentrations of restricted-
range (i.e., local endemic) species or relict
taxa dependent on cool and moist habitats
were also evaluated to refine candidate
mesorefugia locations and boundaries
(i.e., where multiple species boundaries
overlap). These include the distribution of
Brewer spruce (Picea breweriana), Engel-
mann spruce (Picea engelmanni), foxtail
pine (Pinus balfouriana) (Sawyer 2007),
Plethodon and Dicamptodon salamander
species and subgoups (Bury 1973; Mead
et al. 2005; Steele and Storfer 2006), and
numerous other plants (Sawyer 2007) and
invertebrates (Olson 1992), such as harvest-
man (Briggs 1969, 1971ab), millipedes
(Gardner and Shelley 1989; Olson 1992),
trapdoor spiders (Cokendolopher et al.
2005), and land snails (Frest and Johannes
1993). We stress the mesorefugia proposed
here are provisional and will benefit from
more rigorous analyses of biophysical
predictors and species distributions.
Based on these criteria and species distribu-
tion maps, important mesorefugia for the
Figure 2. Provisional mesorefugia (ovals) within the Klamath-Siskiyou Ecoregion, southwest Oregon
and northern California, approximated from large-scale predictors (e.g., coastal mountains in areas of
relatively high precipitation) and an overlay of the distribution of mesophilic, restricted-range species
including Plethodontid and Dicamptodon salamanders, Caseyid millipedes, Pentanychid harvestman,
endemism zones for vascular plants, and relict conifers. Mesorefugia likely contain concentrations of
restricted-range species due to their persistently wet conditions and long-term stability. Dashed ovals
represent high-elevation refugia that may, or may not (depending on the severity of warming tem -
peratures at higher elevations), function well under current and future human-caused climate change.
Numbering refers to locations discussed in the text.
Volume 32 (1), 2012 Natural Areas Journal 69
KSE include: (1) Kalmiopsis; (2) North
Siskiyou Mountains; (3) East Siskiyous; (4)
north of the southern bend of the Klamath
River; (5) West Siskiyous; (6) Lower Scott
Bar River; (7) Russian Wilderness; (8)
Lower Trinity River (multiple locations);
and (9) Middle Eel/Yolla Bolly (multiple
locations, numbers correspond to Figure
2). The Russian Wilderness was selected
due to the extraordinary sympatric assem-
blage of conifer species whose presence
could be due to mesorefugia conditions.
The mesorefugia located in the coastal
zone experiences the highest rainfall in
the KSE and is likely to have the highest
concentrations of restricted-range and cli-
mate change-vulnerable species (contrast
Figures 1 and 2). We acknowledge that
much KSE biodiversity occurs outside
of these mesorefugia, but suggest that
ensuring adequate protection of habitats
buffered from warming in these zones is
an important first step.
The current protected areas system does
a poor job of representing the provisional
mesorefugia. Only the Kalmiopsis, Sis-
kiyou, Russian, and Middle Eel/Yolla
Bolly Wilderness areas and redwood parks
encompass portions of likely mesorefu-
gia. In general, Wilderness areas largely
protect higher elevations, not the middle
and lower slopes where most of the mi-
crorefugia are likely to occur. Proposed
expanded reserve networks would repre-
sent all of the provisional mesorefugia, if
implemented, including those at lower and
middle elevations (e.g., contrast Figures
2 vs. 3b). We also propose three priority
mesorefugia corridors to link: (1) Siskiyou
Crest–Kalmiopsis, (2) Kalmiopsis–Sis-
kiyou Mountains, and (3) Trinity/Scott Bar
River–Siskiyou Crest (numbers correspond
to Figure 3a).
We used our microrefugia site features to
identify a set of provisional areas outside
extant protected areas that warrant im-
mediate conservation attention. For the
portion of the ecoregion outside of for-
mal protected areas, 22 highest-priority
microrefugia and 40 high-priority areas
containing late-seral forest and other key
habitat types (e.g., serpentine barrens)
were identified as candidate microrefugia
(Figure 3a). Many important old-growth
forest microrefugia occur in close prox-
imity to existing protected areas, such
as the Kalmiopsis Wilderness. Most of
the candidate microrefugia lie towards
the western, wetter part of the ecoregion
and are generally located at mid and low
elevations. Remnants of late-seral forest in
the fog zone are particularly important to
protect and restore, as they likely contain
a sizable proportion of vulnerable species.
Some old-growth forest blocks at higher
elevation in the eastern part of the ecore-
gion were also recommended, as they span
a broad elevational range and are among
the largest remaining old-growth fragments
in the ecoregion. Data on late-seral forests
were unavailable for some portions of the
ecoregion, such as the southwestern coastal
hills and the foothills of the Central Valley
that may contain additional microrefugia
(Figure 3a).
Finer-resolution analyses and field sur-
veys within priority areas (Figure 3a) are
required to identify the particular blocks
of old-growth forest and bottomland sites
that have the highest potential to act as
microrefugia. The nature of the landscape
and the mosaic of late-seral forests can have
a major influence on the efficacy of mi-
crorefugia. For example, even a relatively
small old-growth forest fragment situated
in a steep, north-facing canyon that experi-
ences shade most of the time will likely
function well as a long-term refuge for
mesophilic species.
In sum, several microrefugia deserve
immediate conservation attention, includ-
ing: southern bend of the Klamath River,
California; lower slopes of the Klamath
River from around China Point eastwards
to Hamburg, California; northern slope
of the Scott Bar Mountains and along the
lower Scott River in California; old-growth
fragments close to the coast in Oregon
and in the foothills behind the redwood
belt in northwestern California; north-
facing slopes of the Middle Smith River,
California; larger old-growth pockets to
the west of the Kalomiopsis Wilderness,
southwest Oregon; southeastern watersheds
of the Siskiyou Mountains (e.g., Dillon
and Rock Creek area, California); northern
Siskiyou Mountains to western Siskiyou
Crest region, California; and a network
of serpentine-substrate areas representing
assemblages of endemic plant species and
their surrounding forest buffers mainly in
southwest Oregon.
This provisional network of priority
climate change microrefugia outside the
existing reserve system should be targeted
for immediate protection and restoration.
A variety of conservation approaches is
required because candidate sites are in
diverse locations, habitat types, tenures,
and land use pressures. Some are located
within active federal and state forestry
zones, and some are on private lands. The
priority areas identified here would not, by
themselves, constitute a comprehensive
conservation strategy as they are intended
primarily to buffer a good portion of the
KSE biota from extinction and extirpation
due to changing climate, and they would not
necessarily address a wide range of other
conservation goals and objectives.
Representation and Existing
Protected Areas
We also intersected remaining late-seral
forests with north-facing slopes (N, NE,
NW, Figure 3ab) and areas of relatively
high precipitation with microrefugia char-
acteristics (see Appendix for methods). Us-
ing ecoregion-scale data on forest cover and
topography, it was challenging to identify
the small river valleys and bottomlands that
consistently pool cooler air and may func-
tion as additional microrefugia. More local-
scale data and on-the-ground surveys are
required to identify potential bottomland
refugia. For similar reasons, we also did not
attempt to identify potential microrefugia
for the vulnerable serpentine flora.
Based on this analysis, the current protected
area network under-represents most of the
important microrefugia for the KSE (Figure
3a). For instance, only 16% of remaining
old-growth forest occurs within strictly
protected areas (Table 1). Some important
70 Natural Areas Journal Volume 32 (1), 2012
Figure 3. (A) Provisional microrefugia (highest priority and priority) and proposed mesorefugia corridors outside (numbers refer to locations described in the text) of formal protected areas in
the Klamath-Siskiyou Ecoregion, southwest Oregon and northern California. High-quality microrefugia inside formal protected areas are not identified. The mature forest shown is north-fac-
ing only. Circles were drawn based on visual inspection of the mapped old forest polygons. (B) Some priority microrefugia in the Klamath-Siskiyou Ecoregion, southwest Oregon and northern
California, which are not encompassed in the proposed expanded reserve network (Noss et al. 1999). Black ovals are highest priority and white ovals are high priority gaps in protected areas
coverages. Circles were drawn by visual inspection of old-growth forest concentrations.
Volume 32 (1), 2012 Natural Areas Journal 71
blocks of lower- and middle-elevation
old-growth microrefugia occur in existing
reserves – such as in the coastal redwood
parks, Kalmiopsis, Siskiyou, Wild Rogue,
and Russian Wilderness areas, and Oregon
Caves National Monument – but many
are located outside these areas. While the
extant reserve system does help protect an
array of ecoregion- and local-endemic plant
and animal species and most of the alpine
and sub-alpine communities in the KSE
(Sawyer 2007), much of the ecoregion’s
biodiversity and many, if not most, of the
vulnerable species occur outside of the
existing protected area network.
Table 1. Area and percentage of north-facing late-seral and old-growth forest (collectively LSOG) in the Klamath-Siskiyou Ecoregion (KSE), southwest
Oregon and northern California, by climate change vulnerability zones, extant protected areas, and proposed conservation areas. Data for old-growth
forests for some portions of the ecoregion (southwestern coastal, southeastern border) were unavailable; thus, coastal old-growth forest area, inside and
outside of protected areas, is underestimated and the drier zone old-growth forest area to a smaller extent.
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72 Natural Areas Journal Volume 32 (1), 2012
Representation and Proposed
Protected Areas
Prior reserve designs proposed for the
KSE include the Phase 1 reserves and
Representation Zones proposed by Noss
et al. (1999), the Siskiyou Crest National
Monument (KS Wild 2010) and Siskiyou
Wild Rivers (Sisikyou Project 2010) pro-
posed by conservation groups, and Scenario
3 Plan “interacting current and near-future
habitat” of Carroll et al. (2010). These
reserves, if implemented, would protect
a large proportion of the critical micro-
refugia within high-precipitation zones
and mesorefugia (i.e., 47% the remaining
old-growth forest and 22% of north-facing
old-growth; Table 1). If all the proposed
reserve expansions were implemented,
then 70% of remaining old-growth forest
and 33% of north-facing old-growth for-
est would be protected. We identified only
five gaps of highest priority and six high
priority microrefugia that were not fully
contained within the proposed protected
area network (Figure 3b). All of the highest
priority gaps are critically important sites
and should receive immediate conservation
attention. Collectively, these gaps contain
important coastal and intact old growth
areas, local pockets of species endemism,
and transitional areas; and they may pro-
vide additional mesorefugia corridors.
Additional and more finely resolved prior-
ity setting of microrefugia is warranted in
the near future. GIS-based spatial analyses
supported by field evaluation of candidate
microrefugia can assess their species
assemblages, landscape context, terrain
position, habitat condition, defensibility,
and complementarity with other candidate
sites. These evaluations can be augmented
by additional analyses of past and future
refugia based on species distributions and
biophysical predictors of climatic and
vegetation stability and identification of
areas predicted to experience wildfires
within historic ranges of frequency and
intensity. In addition, targeted surveys
of old-growth forest invertebrates and
non-vascular plants (e.g., fungi, lichens,
bryophytes) are needed to improve our
understanding of the distribution of distinct
assemblages in order to refine the location
of mesorefugia and better design represen-
tative networks of microrefugia. Potential
refugia for the endemic serpentine flora
need to be identified and prioritized. Such
areas are likely to be mesic serpentine sites
that remain relatively moist even under a
changing climate, due to terrain position
and other biophysical features (e.g., seeps
and bogs). The sites and their surround-
ing buffer habitats need to be identified
and prioritized using a similar approach
as for the old-growth forest microrefugia.
Identifying and protecting microrefugia
complements ongoing modeling of range
shifts for vulnerable species and natural
communities (e.g., Pearson and Dawson
2003; Loarie et al. 2008; Carroll et al.
2010; Damschen et al. 2010; Harrison et
al. 2010), studies of climate sensitivity of
species, analyses of how a changing climate
will affect wide-ranging species, and as-
sessing the cost and cost-effectiveness of
alternative conservation actions.
Large natural landscapes and wilderness,
the foundation of reserve designs, remains
the mainstay of conservation efforts in this
and many other localities and is especially
important in a changing climate. Without
large natural landscapes in relatively good
condition, many of the remaining pockets
of old-growth forest may not persist or
function well as microrefugia. However,
for ensuring a robust reserve design that is
responsive to climate change, it is prudent
to secure priority old-growth forest micro-
refugia as swiftly as possible while the
more time-consuming and uncertain task
of conserving larger landscapes continues.
Waiting decades for formal “gazettement”
of large protected areas without securing
microrefugia now may allow continued
degradation of these critical refuges. Our
recommended approach is somewhat novel
for most conservation advocacy, where
securing larger priority landscapes pro-
posed in comprehensive strategies is often
acted upon first, but the rapidly warming
landscape may require a diversification of
tactics. As Voltaire cautioned, we should
not let the perfect be the enemy of the
We greatly appreciate the contributions to
this analysis by the following individuals:
J. Cokendolpher, L. Farley, J.A. Johnstone,
J.M Ledford, R.A. Progar, J. Sawyer,
and W. Peterman. We thank KS Wild for
permission to use their ecoregion map as
a basemap, S. Harrison for reviewing an
earlier draft, K.E. Iron, and an anonymous
reviewer. This study was sponsored by a
grant to the Geos Institute from The 444-S
Foundation. The opinions expressed are
those of the authors and do not necessarily
reflect the views of 444-S Foundation.
David Olson is a Conservation Biologist
with Conservation Earth Consulting.
Dominick A. DellaSala is Chief Scientist
and President of the Geos Institute, Ash-
land, Oregon, and current President of the
Society for Conservation Biology, North
America Section.
James R. Strittholt is the Executive Direc-
tor and Chief Scientist of the Conservation
Biology Institute, Corvallis, Oregon.
Reed F. Noss is the Davis-Shine Professor
at the Department of Biology, University of
Central Florida, Orlando, and the Presi-
dent and Chief Scientist for the Florida
Institute for Conservation Science.
Jamie Kass is a GIS specialist and con-
Thomas F. Allnutt is a Conservation Spe-
cialists with the Department of Environ-
mental Science, Policy and Management,
University of California, Berkeley.
Marni E. Koopman is a Climate Change
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... Josephine County is also located in a biodiversity hotspot. The study area is part of the Klamath-Siskiyou Ecoregion, one of the most biodiverse temperate forest regions and an area of increasing conservation focus (D. Olson et al., 2012;D. M. Olson et al., 2006). ...
... M. Olson et al., 2006). The Klamath-Siskiyou Ecoregion straddles the Oregon-California border and contains several regions identified as critical climate change refugia (D. Olson et al., 2012;D. M. Olson et al., 2006). ...
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The rapid expansion of cannabis agriculture in the Western United States provides a rare opportunity to study how an abrupt change in land‐use policy affects local biodiversity. There is broad speculation that cannabis production on private land is expanding and having negative effects on aquatic and terrestrial ecosystems, yet there exist little empirical data to evaluate this concern. In this study, we mapped and characterized outdoor cannabis production during the first season of legal recreational production (2016) in a large legacy cannabis‐producing region of Southern Oregon, Josephine County. We descriptively compared cannabis farms to all available private parcels based on proximity to rivers/streams and undeveloped land and their overlap with carnivore richness. Using publicly available satellite imagery, we found approximately 1.34 km2 (331 acres) of cannabis cultivation within Josephine County during the first season of legal recreational production. Most cannabis production areas were small (median size 414 m2), spatially clustered at all observed scales, and recently established (67% were not visible in 2013–2014 pre‐legalization). When compared with all available private parcels, cannabis was preferentially located in forested areas, undeveloped land and slightly closer to rivers. Within riparian areas, farms were slightly closer to rivers with predicted occurrence of coho salmon (Oncorhynchus kisutch). While projected carnivore richness was similar between cannabis and all private parcels, projected fisher (Pekania pennanti) occupancy was more than five times higher on cannabis farms, with a median occupancy of 0.69 (interquartile range: 0.24–0.87). Our results establish a baseline for cannabis land cover at the time of early recreational legalization and rapid expansion and can be used to predict future patterns or ecological consequences of cannabis development in other production areas. Understanding the potential ecological impact of cannabis is increasingly important as legalization expands and may also offer insights into other rural land‐use change frontiers. The expansion of cannabis farming in areas of high value for aquatic and terrestrial wildlife emphasizes the need for landscape planning. In this paper, we combine satellite mapping and species richness to assess cannabis farming configuration for potential ecological consequences. We documented a dramatic increase in new farms and overlap with sensitive species distributions but overall small farm size and total cultivated area.
... Serpentine substrates inhibit forest cover due to nutritional deficiency and/or presence of heavy metals (Kruckeberg 2002). Thus the "serpentine syndrome" (Jenny 1980) may provide the long-term stability necessary to maintain populations of narrowly distributed plants of poor competitive ability (Casazza et al. 2005;Olson et al. 2012) that can tolerate the chemical and hydrological conditions there. Large cliffs, scree, dunes, alpine peaks, ash slopes (Reveal and Björk 2004;Ertter and Moseley 1992) and various types of wetlands also are important habitats for regionally endemic plants, where dense forest cover is persistently excluded, and fires are infrequent and low intensity. ...
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Certain areas of northwestern North America have been identified as plant endemism hotspots previously, but without repeatable methods or comparable results. The prevalent methods among endemism studies give misleading results from partial, often subjectively sampled taxa or by considering only jurisdictional endemics. A quantified approach was needed to assess and compare centers of endemism in northwestern North America to help guide landscape-scale conservation effort. Whole flora, per-taxon weighted endemicity methods were used to assign sum endemicity scores to 1 × 1 degree latitude–longitude grid cells, adjusting for cell area. Extralimital distribution data were considered for endemicity scores. Taxa with an endemicity score over 10 were rejected. Jurisdictional endemics are listed, but because many of these are distributed too widely to be included in the endemicity dataset, they are discussed only to highlight stewardship responsibility. The list of regionally endemic taxa falling within the criteria totalled 1224. Nearly all grid cells having sum endemicity values over 5 occur south of the southern ice-age glacial limits. The highest values occurred in grid cells corresponding to southern regions: the Siskiyou Mountains, the Wenatchee Mountains, the Columbia River Gorge, and the greater Blue Mountain system. However, the entire northern North American Cordillera form a globally significant center of endemism. The taxonomic structure of the regionally endemic flora is examined, and potential causes of the concentrations of regional endemics are explored.
... There are many sources that have explored the region's most pressing conservation issues including Salmon and Acorns Feed the People by Kari Marie Norsgaard (2020), the Karuk Climate Adaptation Plan (2019), Steward's Fork by Jim , and Northwest California by John Sawyer (2006). Many also highlight the Klamath Mountains as a critical biological reserve for temperate North America (Wagner 1997, Noss et al. 1999, Strittholt et al. 2001, Wallace 2003, Olson et al. 2012, Sarr et al. 2015. Most of these discuss the resiliency of Klamath Mountains despite the region being exposed to a legacy of landscape, ecological, and cultural destruction that started with the gold rush over 170 years ago. ...
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This book celebrates the natural history of the Klamath Mountains of northwest California and southwest Oregon through stories of diversity and resilience over deep time. Shaped by geology, these mountains form an ancient jigsaw puzzle and topographic mosaic dissected by big-shouldered river canyons and sharp ridgelines that create localized climatic gradients. Within the geomorphic province, the rocks are much older than in surrounding regions. This dichotomy has allowed many distinct evolutionary lineages of plants and animals to adapt, survive, and sometimes speciate where elsewhere they became extirpated long ago. The Klamath Mountains: A Natural History • Describes and documents one of the most biodiverse temperate mountain ranges on Earth. • The first comprehensive Natural History written for this region. • 34 contributing authors–all experts in their fields. • Chapters including Mammals, Birds, Amphibians, Plant Communities, First Peoples, Geology, Climate, Fire Ecology, and much more. • Full color, rich illustrations, and well-curated photographs bring 496 pages to life!
... Such knowledge can help tribes respond adaptively to reduced salmon populations and habitat quality (Lynn et al. 2013). Western scientific knowledge can be linked to tribal knowledge to better project and anticipate changes in resource availability (Turner et al. 2011) and to identify possible refugia (Carroll et al. 2010, Olson et al. 2012 Hydrologic services include the quantity, quality, location, and timing of water supply (Brauman et al. 2007), with quality and timing the most likely to be affected by climate change (chapter 3). Increasing stream temperatures, higher peak flows, and lower summer streamflows all have the potential to strain water infrastructure, particularly as a result of increasing frequency and extent of extreme events. ...
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Climate change will affect physical hydrological processes and resource values that are influenced by hydrology, including water available for human uses, water quality, roads, and developed infrastructure. Climate change is likely to alter the amount, timing, and type of precipitation, leading to less snow, receding glaciers, more winter precipitation as rain, earlier snowmelt, and fewer summer precipitation events. Anticipated streamflow changes include higher winter peak flow events associated with increased rain and rain-on-snow in mid to higher elevations, and overall declines in summer baseflows. Slower groundwater recession in areas with permeable volcanic rocks may dampen peak-flow increases and summer low-flow declines. Increasing temperature and changes in the amount and timing of precipitation and runoff will also affect water quality, water availability, soils, and vegetation. Roads and trails that were built decades ago are highly sensitive to climate change because of declining condition. Culverts remaining in place beyond their design life are less resilient to high flows and bed load movement and have a higher likelihood of structural failure. In the face of higher severity storms, aging infrastructure and outdated design standards can lead to increased incidents of road failure. In-stream restoration techniques (e.g., adding wood to streams) will improve hydrologic connectivity in floodplains and increase water storage capacity. Reintroducing or supporting populations of American beaver (Castor canadensis Kuhl) may also help to slow water movement and increase water storage. Working across boundaries on water protection plans and water conservation will help ensure adequate water supplies. Sediment delivery to streams from roads can be reduced by disconnecting ditch lines from streams during watershed restoration, timber projects, vegetation management, and road management. Landslide risk will be reduced by stabilizing slopes, mapping landslide risk, locating or relocating roads in areas that are less vulnerable to landslides, and decommissioning roads in vulnerable locations. Streamflow projections that consider climate change can inform decisions on structure type and sizing at stream crossings, as well as decisions about travel management and restoration. Increasing resilience of recreation facilities, stream crossings, historical and cultural sites, and points of diversion to peak flows will improve public safety.
... Karakteristik ekoregion mampu memberikan jasa ekosistem secara alamiah berupa jasa ekosistem pengaturan iklim mikro, yang meliputi pengaturan suhu, kelembaban ,hujan, angin, pengendalian gas rumah kaca dan penyerapan karbon. Faktor abiotik khususnya vegetasi, ketinggian tempat dan bentuk lahan dapat memperngaruhi fungsi pengaturan iklim (Chen, et al.,1999;Harris, et al., 2018;Olson, et al., 2012;Yang, et al., 2018;Chen, 2016). Wilayah-wilayah dengan kepadatan vegetasi rapat dan terletak di pegunungan memiliki sistem pengaturan iklim yang lebih baik dibandingkan dengan wilayah yang memiliki tingkat kerapatan vegetasi rendah (Sudia, dkk., 2019 (Sudia, dkk., 2019). ...
Ecosystem services to regulate air quality, climate, water system and water purification are important ecosystem services for human life and other living things. The objective of the research was to analyze the distribution and value of ecosystem services index of air quality, climate, water system and water purification of Konawe Regency. This research was conducted through the study of ecoregion characteristics, covering landforms, natural vegetation types and land cover. Data analysis includes the calculation of ecosystem services index and spatial distribution of ecosystem services index. The results showed that the dominant type of landform in Konawe Regency was the structural hills of metamorphic rock material with natural vegetation in the form of forests and the dominant land cover was primary dry land forests.The average value of the Ecosystem Services Index (ESI) of air quality regulation were 2.88 (medium), climate regulation and water system arrangements were 3.18 (medium) and 3.12 (medium) and water purification settings was 2.12 (low). The average value of the ecosystem services index of the four types of regulatory services was 2.83 with a moderate category. The average ESI value of Sub District of Latoma, Asinua, Routa, Abuki and Meluhu were 3.92, 3.65, 3.62, 3.51 and 3.49 with high categories, respectively. The performance of environmental services of air quality regulation is dominated by a high category of 221,489.56 hectares or 41.99 percent, while climate regulation was dominated by a very high category of 243,516.50 hectares or 46.17 percent. The performance of ecosystem services of water system and water purification arrangements reached an area of 235,459.44 hectares or 44.64 percent and 32,723.16 hectares or 43.04 percent respectively.Keywords: ecoregion, ecosystem services index, regulating ecosystem services,spatial distributionJasa ekosistem pengaturan kualitas udara, iklim, tata air dan pemurnian air merupakan jasa ekosistem penting terhadap kehidupan manusia dan mahluk hidup lain. Penelitian ini bertujuan untuk menganalisis sebaran dan nilai indeks jasa ekosistem pengaturan kualitas udara, iklim, tata air dan pemurnian air Kabupaten Konawe. Penelitian ini dilakukan melalui kajian karakteristik ekoregion, mencakup bentang lahan, tipe vegetasi alami dan tutupan lahan. Analisis data meliputi perhitunganindeksjasaekosistem dan sebaranspasialindeksjasaekosistem. Hasil penelitian menunjukkan bahwa tipe bentang lahan yang dominan di Kabupaten Konawe adalah perbukitan structural lipatan bermaterial batuan metamorfik dengan vegetasi alami berupa hutanpamah (non dipterokarpa) dan tutupan lahan dominan adalah hutan lahan kering primer. Rata-rata nilai Indeks Jasa Ekosistem pengaturan kualitas udara adalah 2,88 (sedang), pengaturan iklim dan pengaturan tata air masing-masing sebesar 3,18 (sedang) dan 3,12 (sedang) dan pengaturan pemurnian air adalah 2,12 (rendah). Nilai rata-rata indeks jasa ekosistem dari empat jenis jasa pengaturan tersebut adalah 2,83 dengan kategori sedang. Nilai IJE rata-rata Kecamatan Latoma yakni 3,92, Kecamatan Asinua sebesar 3,65, KecamatanRouta sebesar 3,62, serta KecamatanAbuki dan KecamatanMeluhu masing-masing 3,51 dan 3,49 dengan kategori tinggi. Kinerja jasa lingkungan pengaturan kualitas udara didominasi oleh kategori tinggi seluas 221.489,56 hektaratau 41,99%, sementara itu pengaturan iklim didominasi oleh kategori sangat tinggiseluas 243.516,50 hektaratau 46,17%. Kinerja jasa ekosistem pengaturan tata air dan pengaturan pemurnian air mencapai luas masing-masing 235.459,44 hektaratau 44,64% dan 32.723,16 hektaratau 43,04%.Kata Kunci:ekoregion, jasa ekosistem pengaturan, indeks jasa ekosistem, sebaran spasial
... As part of a statewide investigation of reach-scale channel types in California, the 171 reach-scale surveys used in this study exist across a range of channel morphologies (see Supplementary Information). Regional rivers and their tributaries are important refugia for California salmon and steelhead populations (Olson et al., 2012;Power et al., 2015). With the exception of the Smith River, which remains undammed and largely unimpacted by humans, major anthropogenic influences in the basin include logging, mining, and cannabis cultivation in the predominant mountainous landscapes (Palmer, 2012). ...
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Plain Language Summary Deep pools and shallow riffles occur in most river systems and are formed through an interaction between the water flowing through a river and the sediment it carries and deposits. Several more technical hypotheses have been developed as to why pools and riffles form where they do. The original hypothesis, called the velocity reversal hypothesis, suggested that while pools commonly have slow moving water, at higher flood event flows, pools are subjected to greater velocities than riffles, which causes the removal of sediment at the stream bed. While this has been shown to only be true in certain circumstances, we sought to quantify how often velocity reversals do occur. Due to the large field data set, this research presented a unique opportunity to understand how frequently a river process, such as a velocity reversal, occurs across a landscape. We found that velocity reversals are relatively uncommon and occur in only 18% of pool‐riffle pairs. Where reversals do occur, the river narrows and then widens to a greater degree than other locations that are closer to the average width. We suggest that future studies need to focus on the prevalence of river processes in rivers for improved river restoration strategies.
Technical Report
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The climate of California is in a stage of rapid flux. This document highlights past, current, and projected climate change on the Six Rivers National Forest. It is divided into discussion of historical and current conditions and projected future trends by general resource area. This trend summary is produced by the US Forest Service Pacific Southwest Region (R5) Ecology Program to help forest managers plan for, and where possible, mitigate climate change-related ecosystem vulnerabilities. Climate change trend summaries are currently available for all the National Forests of California and are updated on approximately 5-year intervals as new climate science becomes available.
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The climate of California is in a stage of rapid flux. This document highlights past, current, and projected climate change on the Mendocino National Forest. It is divided into discussion of historical and current conditions and projected future trends by general resource area. This trend summary is produced by the US Forest Service Pacific Southwest Region (R5) Ecology Program to help forest managers plan for, and where possible, mitigate climate change-related ecosystem vulnerabilities. Climate change trend summaries are currently available for all the National Forests of California and are updated on approximately 5-year intervals as new climate science becomes available.
Technical Report
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The climate of California is in a stage of rapid flux. This document highlights past, current, and projected climate change on the Klamath National Forest. It is divided into discussion of historical and current conditions and projected future trends by general resource area. This trend summary is produced by the US Forest Service Pacific Southwest Region (R5) Ecology Program to help forest managers plan for, and where possible, mitigate climate change-related ecosystem vulnerabilities. Climate change trend summaries are currently available for all the National Forests of California and are updated on approximately 5-year intervals as new climate science becomes available.
Technical Report
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The climate of California is in a stage of rapid flux. This document highlights past, current, and projected climate change on the Shasta-Trinity National Forest. It is divided into discussion of historical and current conditions and projected future trends by general resource area. This trend summary is produced by the US Forest Service Pacific Southwest Region (R5) Ecology Program to help forest managers plan for, and where possible, mitigate climate change-related ecosystem vulnerabilities. Climate change trend summaries are currently available for all the National Forests of California and are updated on approximately 5-year intervals as new climate science becomes available.
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The Klamath-Siskiyou Ecoregion of northwest California and southwest Oregon has been regarded as an area of extraordinary biodiversity. Despite this recognition and the growing interest in the region's biological significance, the global importance and status of this ecoregion is underappreciated by the public, resource managers, and decision makers. We reviewed the conservation importance and status of the Klamath-Siskiyou Ecoregion relative to that of 30 temperate coniferous forest ecoregions in the United States and Canada and also compared the results to a related global comparison of diverse forest ecoregions. Based on comparisons of species richness, endemism, unique evolutionary and ecological phenomena (e.g., species migrations, adaptive radiations), and global rarity of habitat types, we ranked the biodiversity of the Klamath-Siskiyou Ecoregion among the world's most outstanding temperate coniferous forests. We identified a total of 2,377 species for six terrestrial taxa that we analyzed: native plants (78%, n=1,859), birds (9%, n=222), butterflies (6%, n=141), mammals (3%, n=69), land snails (2%, n=54), and reptiles and amphibians (1%, n=32). Of this total, 168 species (7%) occur nowhere else in the world. The ecoregion supports a continental maximum of conifers (30 species); up to 17 species have been recorded in an area of 2.6 km 2. The combined freshwater habitats of the region support exceptionally high levels of endemism: 14 of 33 (42%) fish and 142 of 235 (60%) mollusk taxa are endemic to the region. We ranked the status of the region's terrestrial biodiversity as endangered. Approximately 25% of forests are intact and 10.5% are legally protected (e.g., as congressionally designated wilderness) from logging. We identified 24 stand types and plant series considered distinctive by the California Native Plant Society, 2 forest ecosystem types (old-growth and mature, riparian forest) considered threatened or endangered by the National Biological Survey, and 10 plant communities listed as critically globally imperiled (G1) or globally imperiled (G2) by The Nature Conservancy. We documented 138 terrestrial and 16 freshwater taxa with state or federal listing status, 5 terrestrial species extirpated from the region. More than half of the listed terrestrial taxa were restricted geographically to the region (i.e., endemics) or were limited to elevations ≤1,524 m where few protected areas occurred. Most mollusk populations have declined dramatically (>90% historic range contractions) throughout the region, and 11 fish taxa (especially anadromous salmonids) have a special status designation due to extensive habitat degradation and changes in hydrology and water quality.
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The high biodiversity and physical heterogeneity of the Klamath-Siskiyou Ecoregion of the Pacific Northwest (USA) suggest the need for an ambitious and multifaceted approach to conservation research and planning. We developed a process of reserve selection and design that proceeds along three parallel tracks: (1) protection of special elements, such as rare species hotspots, old-growth forests, and key watersheds; (2) representation of physical and vegetative habitat types; and (3) maintenance of viable populations of focal species (e.g., fisher, Martes pennanti Erxleben). Each of these complementary research tracks identified important conservation opportunities in the region. In combination they provide a basis for a reserve design and management plan that meets conservation goals better than the existing management situation established by the federal Northwest Forest Plan. Our proposed Phase I reserve design begins with protection of roadless areas on public lands that score high under the criteria of our three-track approach. A relatively small area of additional public and private land is necessary to provide habitat contiguity among roadless areas and capture remaining biological hotspots. This design would place approximately 34% of the region into the strictest category of protected areas, compared to 13% under current management, and would place an additional 19% of the region into moderate protection. A second, proposed phase of conservation would include protection of additional private lands to meet representation objectives. Also included in Phase II would be protection of linkages to other regions, necessary for long-term persistence of wide-ranging animals such as large carnivores (e.g., gray wolf, Canis lupus L.), which are being considered for reintroduction to the region. When implemented, Phase II would bring approximately 60-65% of the region into strict and moderate protection. Linkage design and ecological management (e.g., fire regimes) are among the critical topics for further research.
Extensive pitfall trapping in the Siskiyou and southern Cascade Mountains in southwestern Oregon, USA, revealed the presence of four new species of Antrodiaetus spiders (Antrodiaetidae) as well as numerous examples of the rarely reported Hexura rothi (Mecicobothriidae). The new species are: Antrodiaetus ashlandensis, A. coylei, A. effeminatus, and A. metapacificus. Additional records were also obtained for Antrodiaetus pugnax and Atypoides gertschi (Antrodiaetidae). Distributional data are provided for each species. The four new species are described and illustrated and a taxonomic key to all mygalomorph spiders from southwestern Oregon is provided. Further, each of the previously described Antrodiaetus spp. from the region is diagnosed. The morphology of the male genital plate is proposed as a potentially useful taxonomic character.
Geology, vegetation, and flora are causally linked in the Klamath-Siskiyou Province of northwestern California and southwestern Oregon. The complex mountain topography, with its diverse lithologies and soils, and the spatial-temporal isolation of the region have fostered the evolution of a rich array of plant communities and a remarkable flora with many endemic taxa. Plate tectonics have played a major role in creating a complex mosaic of landforms and rock types, the latter ranging from igneous types (intrusives like granitics and ultramafics, as well as extrusives) to metamorphics (schists, slates, and serpentines) and a variety of sedimentary rocks. The vegetation is dominated by conifer forests, often with associated broad-leaved evergreen trees. Conifer diversity is unusually rich: 31 species in 10 genera are known for the region. The greatest number of plant endemics occur on ultramafic rocks, mostly serpentines. Serpentine plant communities range from Jeffrey pine savannas, xeric shrub types, and serpentine barrens, to the hygric Darlingtonia fens. Preservation of this world-class bioregion is complicated by multiple ownership of lands spanning state borders and by the presence of valuable resources such as timber and minerals.
The overall amount of precipitation deposited along the West Coast and western cordillera of North America from 25°to 55°N varies from year to year, and superimposed on this domain-average variability are varying north-south contrasts on timescales from at least interannual to interdecadal. In order to better understand the north-south precipitation contrasts, their interannual and decadal variations are studied in terms of how much they affect overall precipitation amounts and how they are related to large-scale climatic patterns. Spatial empirical orthogonal functions (EOFs) and spatial moments (domain average, central latitude, and latitudinal spread) of zonally averaged precipitation anomalies along the westernmost parts of North America are analyzed, and each is correlated with global sea level pressure (SLP) and sea surface temperature series, on interannual (defined here as 3-7 yr) and decadal (>7 yr) timescales. The interannual band considered here corresponds to timescales that are particularly strong in tropical climate variations and thus is expected to contain much precipitation variability that is related to El Nino-Southern Oscillation; the decadal scale is defined so as to capture the whole range of long-term climatic variations affecting western North America. Zonal EOFs of the interannual and decadal filtered versions of the zonal-precipitation series are remarkably similar. At both timescales, two leading EOFs describe 1) a north-south seesaw of precipitation pivoting near 40°N and 2) variations in precipitation near 40°N, respectively. The amount of overall precipitation variability is only about 10% of the mean and is largely determined by precipitation variations around 40°-45°N and most consistently influenced by nearby circulation patterns; in this sense, domain-average precipitation is closely related to the second EOF. The central latitude and latitudinal spread of precipitation distributions are strongly influenced by precipitation variations in the southern parts of western North America and are closely related to the first EOF. Central latitude of precipitation moves south (north) with tropical warming (cooling) in association with midlatitude western Pacific SLP variations, on both interannual and decadal timescales. Regional patterns and zonal averages of precipitation-sensitive tree-ring series are used to corroborate these patterns and to extend them into the past and appear to share much long- and short-term information with the instrumentally based zonal precipitation EOFs and moments.
List of Illustrations List of Tables Acknowledgments Abstract Introduction 1. History of Botanical Observations on the Serpentine Flora of California 2. Geology of Serpentine and Related Ultramafic Rocks 3. Serpentine Soils and the Mineral Nutrition of Plants 4. Physiological and Morphological Responses to Serpentine 5. Serpentine Vegetation in California 6. Serpentine Flora in California 7. Serpentine Fauna in California 8. The Evolutionary Ecology of Serpentine Biota in California 9. Exploitation of Serpentine and Other Ultramafics and Effects on Plant Life 10. Land Management and Conservation on Ultramafics Summary Appendices Literature Cited Plates