PowerPoint Presentation

THE UNIQUE ARTHROPOD BIODIVERSITY OF THE KLAMATH/SISKIYOU MOUNTAIN REGION IN NW USA

CHALLENGES FOR INVENTORY AND CONSERVATION

A. R. Moldenke1, B. G. Marcot2, D. DellaSala3 & N. Rappaport4

1Dept of Entomology, 2046 Cordley Hall, Oregon State University, Corvallis, OR 97331-2907; 2US Forest Service, 1221 SW Yamhill St., PO Box 3890, Portland, OR 97208-3894; 3World Wildlife Fund, 116 Lithia Way – Suite 7, Ashland, OR 97520; 4Forest & Range Experiment Laboratory, USDA Forest Service, Albany, CA.

E mail: moldenka@bcc.orst.edu

ABSTRACT:

This region has long been recognized as of extreme significance botanically. Escape from glaciation, diversity of geologic substrates combined with varied relief, and location at the interface of mesic vs. xeric biomes should have rendered this region as unique entomologically as it is botanically. Though scattered literature supports this hypothesis, a careful documentation of the endemic levels of arthropod biodiversity needs to be undertaken.

The World Wildlife Fund, the Forest Service (land owners) and entomologists from Oregon State University are collaborating in a unique attempt to define and protect the ecological processes in which arthropods participate and to preserve biodiversity hot-spots and premier taxa, while permitting economic utilization of the forest resources as a sustainable long-term resource.

Relict ancient taxa representative of the transcontinental forests before the Miocene mountain orogeny split the continent in two characterize this region (i.e., Tricholepidion gertschi (Microcoryphia) endemic to CA; Cryptocercus punctulatus (communal Blattaria) amphi-continental distribution).

Beta-diversity is driven by habitat heterogeneity and recent adaptive radiation (i.e., Amaurobiidae (Araneae)). Additionally, taxa with limited mobility have spawned localized geographic isolates as they recolonized the Pacific Northwest after glaciation (i.e., Pleocominae (Scarabaeidae), Caseyidae (Diplopoda)).

Though the vast majority of taxa inhabiting the region is widely distributed geographically, endemicity is likely to be relatively high.

With adequate inventory a system of protection can be implemented before this ecosystem is more heavily impaired.

Who Cares?

Under the current and new “ecosystem management” paradigm for forested lands of the US Federal Government (Forest Service) biodiversity and ecosystem processes are of paramount importance. Thus, one management requirement is knowledge of the pattern of biodiversity across the landscape.

Are there regions of higher species diversity (hotspots)?

Are there regions characterized by higher species endemicity?

Arthropod species are also important for what they do. Who are the prime pollinators, nutrient cyclers, herbivore controls?

Examples:

Harpaphe haydeniana (millipede) – this one millipede species feeds

upon 33-50% of all the dead deciduous leaves and coniferous needles

that fall upon the forest floor. By crushing up the plant cells it allows the

process of microbial nutrient recycling to begin.

Eulonchus tristis (acrocerid fly) – this species is the prime pollinator of several dozen

genera of plants on the old-growth forest floor, and also the prime population regulator

of the invertebrate alpha-predator of the forest floor (trap-door spiders).

Background:

Long ago in the Miocene period, the transcontinental mesic forests of North America were split, leaving a small forest “island” on the West Coast. (Klamath Mountains long predate the Cascades, Sierras and Coast Ranges.)

-During this period, the global climate cooled and the warm subtropical flora receded to the South.

-The Rocky Mountains continued to build and the Cascades and Sierras began to uplift, resulting

in the drying and formation of the Great Basin and the Great Plains.

-The arid-adapted flora and fauna of the Southwest US and Mexico spread into the region.

CURRENT EXAMPLES RESULTING FROM FOREST ISLAND ON WEST COAST :

• Ancient relict “Palaeoendemics” in western North America

Sequoia (conifer); Ascaphis (frog); Tricholepidion (Microcoryphia)

• Taxa with a Split-continental distribution

Torreya (conifer); Plethodontidae (salamanders); Cryptocercus (Blattaria)

Most of the basic floral relationships of today were established in this region by the end of the Miocene/Pliocene. Later, during the Pleistocene, warm ocean-current circulation spared much of the Klamath/Siskiyou Region from glaciation – followed by a rapid colonization and radiation throughout adjacent areas. Alternating cooler and warmer periods left isolated mesic plant stocks on north-facing higher altitudes and dry-adapted species on open-canopy xeric serpentine habitats.

“Neoendemics” in Klamath/Siskiyou region:

• Plant radiation/speciation on serpentine soils

• Rasenkreise of Ensatina eschscholtzii (salamander)

• Parapatric swarms of poorly dispersed arthropods such as millipedes

in the family Caseyidae and flightless pleocomine Scarabaeidae.

Survey Design: Field Protocols

Alpha-diversity & beta-diversity

Experimental Units:

Adjacent pairs of 40-80 acre watersheds (15-30 hect.)

(standard US Forest Service management units)

Biodiversity Drivers (established by prior studies):

1o determinant – season

Hypothesis: Within the Pacific Northwest forest, the turnover in both species

presence and activity levels between wet and dry seasons increases with decreasing latitude. Most summer-active taxa are derived from “Madro-Tertiary” stock which have colonized from the arid SW and Mexico.

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2o determinant – successional stage

Hypothesis: Arthropod biomass should increase throughout the year in early successional stages in the North (WA) due to the large annual photosynthetic production in clear-cuts; however, moisture limitation in the Klamath mountains should force most summer arthropod activity into the forest shade. In the summer and fall insectivorous vertebrate activity should be greater in clear-cuts in the North, but mature forests in the South.

typical pattern of successional comparisons:

a) whole groups in one stage only

ex: Apoidea in early succession (200+ spp)

b) individual species in one stage only

ex: Taracus (Phalangid) in mature forest

c) sibling species in alternate successional stages

ex: Araneus mariposa in early succession

Araneus nordmanni in mature forest

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3o determinant – exposure or slope-face

Hypothesis: In the North (WA) there should be higher species turnover with differing slope-face in the early succession than in the mature forest; in the South (Klamath/Siskiyou) species turnover dependent upon slope-face should be greater in the mature forest. In the North forest canopy is usually dense enough to significantly insulate the understory. In the South the clearcuts are so dry that it makes little difference what the slope-face is; under the forest canopy the moisture gradient is prominent.

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4o determinant – edaphic substrate specialization

In Klamath Region the dominant plant genera on serpentine soils are the same as those on

other soil types but the species are all restricted to serpentine (i.e., trees: Pinus, Quercus; shrubs: Arctostaphylos, Ceanothus). Many plant genera are restricted only to serpentine (ex: Darlingtonia).

QUESTION:

Are the insect faunas different as well?

Goals of Field Research Component:

Description of how alpha-diversity of a number of arthropod groups differ:

(1) within a site throughout the seasons

(2) & how species are replaced (beta-diversity) between adjacent sites

differing in either successional stage, slope-face, or soil type.

Library Research: Reference monographs

Gamma-diversity & endemism

There are 5 major patterns, generally speaking for arthropods as a whole, of geographic distributions characteristic of species inhabiting the Klamath/Siskiyou Region. (Individual taxonomic groups differ widely from the norm.)

montane transcontinental Cascade-

w. N.Am sub-boreal Sierras

(30%) (20%) (20%)

Xeric endemic others

Great Basin Klamath (variable)

(15%) (10%) (5%)

Classic examples of Klamath/Siskiyou endemism:

a) strong Klamath/Siskiyou richness hotspot

Klamath Region = 45 spp of Amaurobiidae all endemic

Rest of N Amer = 38 spp nearly all very widespread

b) edaphic endemism

(1) limestone endemism

subterranean blind cavernicolous millipede –

Aprosphylosoma (monotypic genus)

(2) serpentine endemism

(associated with nearly ALL of the plant endemicity)

Question: are there more examples from arthropods??

Forest management practices can be adapted to insure continued alpha-diversity and forest ecosystem health. Once we know the pattern of diversity these can be maintained with preserves (if any are needed in addition to those established for rare plants or vertebrates), or adequate buffers.

However, the scientific community needs to detail which arthropod taxa are really unique to the Pacific Northwest and occur nowhere else. Which bugs are analogous to the unique redwood?

This is not as much a question of conserving biodiversity through management protocols as it is better understanding the evolutionary uniqueness of the region, and developing an appreciation for the life-forms we have that exist nowhere else.

Punchline:

The World Wildlife Fund has designated the Klamath/Siskiyou region as one of the areas of most critical concern for “biodiversity conservation” worldwide.

Botanists and herpetologists appreciate the area’s unique taxa.

Entomologists now need to learn and carefully document just how significant this region is !