Alpine Hawai’i Images from Mauna Kea: https://vimeo.com/63766463 Alpine Hawai’i Two high Hawaiian islands have alpine climate on their summits, characterized by high winds and cold, dry air Summits shaped by glacial activity during pleistocene (geological epoch from 2,588,000 to 11,700 years ago, spanning recent period of repeated glaciations) Alpine Hawai’i – Big Island Two volcanic summits nearly 14,000 feet: Mauna Loa – 13,676 feet “Long Mountain” Mauna Kea – 13,796 feet “White Mountain” Summit of Mauna Loa covered in snow Alpine Hawai’i – Maui One volcanic summits nearly 10,000 feet: Haleakala – 10,023 feet “house of the Sun” The volcanic plateau around the Haleakala crater (2,750 m) Alpine Glaciers Last glacial period (80 – 10 Kya) Mauna Kea - Glaciers formed about 70,000 years ago and from approximately 40,000 to 13,000 years ago At their maximum extent, glaciers extended from summit down to between 3,200 and 3,800 m elevation (10,500 and 12,500 ft) Glaciers eroded the mountain and created deposits Mauna Loa - If glacial deposits were formed, they have long since been buried by younger lava flows Glacial Erosion and Deposits Glacial deposits ion Mauna Kea: terminal moraines ("m") and till ("w") Glacial Erosion and Deposits Terminal Moraine: Forms at snout of a glacier, marking its maximum advance May coincide with the end moraine End moraine marks present glacier boundary Glacial Till: Unsorted glacial sediment - sharp Coarsely graded and heterogeneous Glacial Lakes Mauna Kea is home to Lake Waiau, the highest lake in the Pacific Basin at an altitude of 3,969 m (13,022 ft) Lies within the Puʻu Waiau cinder cone and is the only alpine lake in Hawai’i Very small and shallow lake, with a surface area of 0.73 ha (1.80 acres) and a depth of 3 m (10 ft) Glacial Lakes Lake Waiau - Radiocarbon dating of the lake sediments indicates it was clear of ice 12,600 years ago. Usually, permeable Hawaiian lavas prevent lake formation by water infiltration. Two explanations: - sulfur-bearing steam altered volcanic ash to low-permeability clays - explosive interactions between rising magma and ground / surface water formed fine ash with reduced permeability Alpine Weather Conditions Wide temperature range: from -2 to 20 deg. C. Daily variation (min to max: -2 to 14 deg. C.) Seasonal variation (max: 4 to 18 deg. C.) Alpine Weather Conditions - Snow and ice - Strong winds (to 70 mph) - Low oxygen concentrations (50% sea level) - Very low humidity (~10%) - Very strong UV radiation Alpine Hawai’i Vegetation In spite of nightly freezing temperatures and intense ultraviolet radiation, lichens and mosses dot this aeolian (wind-influenced) ecosystem Lichens: Composite organisms consisting of a fungus (mycobiont) and a photosynthetic partner (photobiont or phycobiont) growing together in a symbiotic relationship The photobiont is usually either a green alga (Trebouxia) or cyanobacterium (Nostoc) Alpine Hawai’i - Plants Metrosideros polymorpha ("multi-statured“) of family Myrtaceae, stunted by dry conditions, and growing on lava flow at (Mauna Loa, 2700 m) Tetramolopium alpinum (Asteraceae) schlerophyll vegetation (Haleakala, 2750 m) Dubautia menziesii (Asteraceae) succulent vegetation (Haleakala, 3050 m) Alpine Hawai’i - Insects Alpine summit zone inhabited by at least 12 cold-hardy native insects and other arthropods Unique, flightless wëkiu bug (Nysius wekiuicola), discovered in 1979 on the summit cone of Mauna Kea “Wëkiu” means “summit” in Hawaiian This predator – size of a grain of rice – is dependent on fresh insects blown up the mountain from lower elevations It hunts for prey lodged in scoria and crevices, and waits along the edges of snowmelt for its meals Alpine Hawai’i - Insects Lab studies revealed amazing blood chemistry that kept wëkiu from freezing until 1.4° F (-17 deg. C) A sister species, Nysius a‘a, also sucks blood from insects, is found only on Mauna Loa Alpine Hawai’i – Other Arthropods The omnivorous cutworm caterpillars; are moth larvae that hide under soil during day, coming out in dark to feed voracious Lycosa wolf spiders and centipedes (Lithobius species) … that prey on insects Alpine Hawai’i - Insects Alpine Hawai’i - Insects Springtails (Entomobrya kea) - tiny insects that jump using built-in springs on their tails Three species at the 13,800-foot cinder-cone summit of Mauna Kea Most species have an abdominal, tail-like appendage, the furcula, that is folded beneath the body to be used for jumping when threatened. It is held under tension and when released, snaps against the substrate, flinging springtail into air Alpine Hawai’i - Plants Argyroxiphium sandwichense (Asteraceae), the "silversword", Hawaii's giant rosette Covering with grey hair – high albedo protects from strong sunshine Silverswords Originates from the tarweed subtribe (Madiinae) of sunflower tribe (Heliantheae) in aster family (Asteraceae) Hawaiian silversword alliance consists of about 30 species in three genera (Argyroxiphium, Dubautia,Wilkesia) Species exhibit extraordinary range of anatomical, morphological, and ecological adaptations; despite being very closely related as evidenced by molecular studies Silverswords Argyroxiphium genus – high elevation specialists - Largest species (A. sandvicense) split into two subspecies: A. sandvicense macrocephalum East Maui (Haleakala) A. sandvicense sandvicense Island of Hawai’i (Mauna Kea) Silverswords - A. sandvicense - split into two subspecies: Silverswords - Highly restricted (A. kauense): From Mauna Loa’s slopes Inhabits much broader range of habitats, and is found in montane shrubland, bogs, open mesic forest Threatened by damage from feral pigs, goats, and sheep Three known occurrences, for a total of 1000 individuals Listed in the U.S. E.S.A. Silverswords - Highly restricted A. kauense: Mauna Loa’s slopes Silversword Pollination Silverswords cannot produce fertile seeds without cross-pollination. Therefore, depend on insect pollinators Native moths, flies or bees travel in a circle around the perimeter of the blossom gathering pollen Silverswords subject to Allee effect, whereby individuals experience reduction in pollination and seed production when the pollinator populations are small … or sparse Robert Robichaux pollinating a silversword Silversword Pollination Measured pollen limitation and self-incompatibility in this species through two pollination experiments conducted over multiple years Examined temporal variation in reproductive success of Haleakala silversword over five years, to determine: if plants flowering out of synchrony with most of the population (i.e., during low flowering periods) exhibit lower percent seed set than synchronously-flowering plants (i.e., during high flowering periods) (Forsyth 2003) Silversword Pollination Number of flowering plants varied greatly among years, as did reproductive success Percent seed set was significantly correlated with number of plants flowering annually, such that plants flowering in high flowering years (1997, 2001) exhibited higher percent seed set than plants flowering in low flowering years (1998, 1999, 2000) (Forsyth 2003) Silversword Pollination In 3-year pollen limitation study, plants flowering asynchronously were pollen-limited, whereas plants flowering synchronously were not Result suggests pollination is strongly density-dependent (Forsyth 2003) Silversword Pollination In another 2-year pollen limitation study, plants with cross-pollination did much better than plants with self-pollination Suggests results this species is strongly self-incompatible (Forsyth 2003) Silversword Life History Silverswords live for 10 to 50 years. At end of their life, they grow flowering stalk that can grow over 6 feet tall within a few weeks, and produce up to 600 flower heads. After being pollinated, the silversword dies. Seed germination affected by environmental conditions: Optimal in moist and shady Conditions (“nursery effect”) Higher ability to germinate for seeds in flower stalks In mesic environments, grasses competed with seedlings (Walker & Powell 1995) References Forsyth, S.A. (2003). Density-dependent seed set in the Haleakala silversword: evidence for an Allee effect. Oecologia 136(4):551-557 Walker, L.R., and Powell, E.A. (1995) Factors Affecting Seed Germination of the Mauna Kea Silversword in Hawai'i. Pacific Science 49(3):205-211 He’eia Fish Pond (Sat. April 23) Please bring following items to the workday: Covered Shoes or Tabis (mandatory to participate) Clothes you don’t mind getting dirty and wet Hat and Sunscreen, Water Bottle Optional: Towel, Dry Clothes NOTE: Work from ~ 9 to ~ 11 (done by 12) They will feed us lunch (not veggie) He’eia Fish Pond– Saturday April 23 Meet at HLC at 8.00 OR at the site: 46-077 Ipuka Street http://paepaeoheeia.org/ What’s Next ? • Final Lecture – April 25th: Not included in Exam • Midterm II – April 27th: Includes Today’s Lecture • Final – May 2nd 8:00 – 9:45 Symposium (In Class) - Group Oral Presentation (5 groups) 15% - 15 minute presentation - 5 minutes questions / answers - Individual Extended Abstract 10% • Individual Take-Home Final – May 6th (by email) 10% - Self-evaluation & Project questions .