Introduction and Key to Plant Communities
| ATV | All terrain vehicle, commonly referred to as a 4-wheeler or wheeler. |
| ablating | When referring to glaciers: melting, receding. |
| Advanced regeneration | Smaller older trees in the forest understory that grow rapidly when a neighbor dies and opens a gap in the canopy. |
| alluvial fan | A large, fan-shaped deposit of materials carried by water and created at the spot where a stream emerges from a steeper, narrower valley onto a wider, flatter area. |
| Alpine | Above treeline. |
| anadromous fish | Fish that spend most of their lives in saltwater, but return to freshwater to spawn and develop. |
| anaerobic | Without oxygen. Most organisms need oxygen to survive, but some decomposing bacteria are able to thrive in it's absence (using sulfur) |
| andisol | A specific soil "order" of soils with a high volcanic ash content |
| Aquatic plant | A plant that grows in standing water, usually submerged, or with floating leaves; or emergent, rooted beneath the water surface, but growing above it. |
| Aquic | In soil taxonomy, a type of soil that has features indicating it is saturated to near the surface for a significant portion of the growing season. |
| Autecology | The study of single organisms and how they relate to their environments. Synecology is the study of many organisms and their surrounding environment. |
| backslope | The broad, even portion of a slope between its lower foot- and toe-slope portions, and upper shoulder, ridge or terrace portion. |
| basin | A cup-shaped area on a large scale- usually at the beginning of a stream. Also the whole area that catches the water feeding the water body- can be synonymous with watershed. |
| beta diversity | Second order diversity- the diversity of groups, rather than the items that make up the groups, which could be called alpha diversity. |
| cations | Positively charged particles- usually minerals, like potassium and phosphorus, that are important in plant and ecosystem productivity. |
| centimeter (cm) | 0.39 inches |
| centroid | The center point of mass or volume |
| Co-dominant | When referring to plants in this document, a plant that covers nearly as much ground as the plant that covers the most ground. For practical purposes, all plants covering more than about 10% in any given layer (e.g the tall tree layer, the low shrub layer, the ground layer) is considered a co-dominant. See also the "dominant" definition, below. |
| Cogener | Member of the same genus. Scientific names are termed binomials, bi- for two and -nomials for names, because they consist of two names. The first name is the genus, the second the species. |
| complex | A wetland polygon composed of more than one map component at a scale too fine to map at 1:25,000. |
| discharge area (Slope) | An area where groundwater discharges, usually to a wetland or stream, and often at a sudden change in slope. |
| distal | Further away |
| Dominant | When referring to plants in this document, the plant covering the most ground. Dominance refers to ecological dominance, so a plant that does not cover the most ground may be exerting more control than it's extent indicates. Usually cover is a pretty good indicator of dominance, and it is relatively simple to measure. |
| ecosystem | A group on organisms interacting with their environment. In this case, we have named the commonly occurring wetland ecosystems of the Kenai Lowlands. |
| Eklutna moraine | A moraine on the Kenai lowlands of a specific age, which is unknown, but before the last two, less extensive, glaciations: The most recent Naptowne and the intermediate Knik. Eklutna time was the last time that nearly the entire Kenai lowland was covered by ice. |
| emergent | When referring to a plant: one rooted below standing water, but growing out of the water. |
| entisol | A specific soil order of soils that are developing, and show little layering, or "horizonation". |
| entrenched | When referring to a stream, a stream deeply cut into its valley. |
| epipedon | Literally: "above the soil"; the uppermost layer of soil. |
| ericaceous | A specific group of plants- usually shrubs often with leathery leaves. Labrador tea, crowberry and blueberries are ericaceous shrubs. |
| estuarine | The area where a freshwater stream enters saltwater. The most productive ecosystems. |
| evapo-transpiration | Moisture lost through passive evaporation, and active transpiration, the water that plants lose when converting food to energy. |
| fen | A peatland that has less acid groundwater with a higher mineral content than a bog. |
| first order stream | A stream that has no tributaries emptying into it |
| flark | A low spot between shrubby peat ridges (strangs); occupied by sedges. If occupied by standing water, then the feature is called a pool. Strangs, flarks and pools often occur in extensive complexes known as patterned fens. |
| floristic | Relating to plants |
| fluvial | Relating to river or stream flow. |
| foot-slope | The area at the base of a slope, where the slope starts to flatten, but above the area where the slope nearly completely flattens, the toe-slope. Not all slopes have both foot- and toe-slopes. |
| geographic information system | Interactive computer maps that include data accessed by clicking on the map. |
| geomorphologic features | Elements of the landscape such as rivers, hills and slopes. On the Kenai Lowlands many glacier-created features such as kettles, moraines and kames are present. |
| glacio-fluvial | Glacier stream/river generated- often refers to layers of sands and gravels laid down by glacial river action. |
| graminoid | Grass-like plant. |
| Halophytic | Referring to salt tolerant plants. A halophile is a halophytic plant- a "salt-loving" plant. |
| headwater | The area just above the beginning of a stream |
| hectare (ha) | 2.471 acres |
| Heterogeneous | Composed of many varied elements; diverse, varied. |
| histosols | A specific soil "order" of soils with a thick (greater than 40 cm or 18 inches) organic layer on top. Indicates wetland conditions. |
| Homogeneous | Composed of few elements; uniform. |
| hummock | A low mound, usually of peat, caused by frost heaving. |
| hydraulic conductivity | The capacity for a substance (soil) to conduct water through it. measured in units of volume (e.g. cubic inches) per unit time (e.g. seconds). |
| Hydric | Wet, when referring to a soil. |
| hydrology | The study of water and how it moves across and under the land. |
| Hyporheic | The zone near and under a stream or river where groundwater and surface water mix. This is where groundwater contaminants can enter a stream, and and important place for aquatic insects and developing salmon eggs. |
| Impervious surface | A surface that acts as a barrier to the downward movement of water (from rain and snowmelt) into the soil. Refers to a human generated surface with lower ability to allow water to pass through than the original natural surface. |
| inclusion | An atypical portion of a map unit that is not part of the map unit's name, and may be quite different than the map unit as a whole. Because nature is variable, inclusions are common. |
| Interlobate moraine | On the Kenai Lowlands, a specific modified moraine that occupies the lake studded country between Nikiski and Sterling. |
| Isostatic rebound | When the land rises after a weight is removed; on the Kenai this is happening since the glaciers have receded at the end of the Pleistocene. |
| kame | A pile of rocks- a small hill- left behind at the edge after a large, no longer moving, glacier has melted. |
| Killey advance | The less extensive glacial advance just after the Moosehorn; both occur during the Naptowne glaciation, the last major ice advance on the lowlands. |
| kilometer (km) | About 5/8 of a mile |
| Knik glaciation | The more extensive glaciation just before the most recent, Naptowne glaciation. The Knik left many steep slopes with thin or no glacial deposits. |
| lag deposits | Coarser deposits that are left behind after the finer materials have been washed away. On the Kenai Lowlands, they usually indicate the edge of an eroded moraine, or terrace. |
| landform | A feature on the landscape, such as a hill, terrace or moraine |
| Levee | A berm or low ridge of unconsolidated material, usually sand and gravel, adjacent to a stream or tidal channel. |
| lithified | Turned into rock. Sediments, over time with heat and pressure, become rocks. |
| little ice age | A cold period when glaciers significantly advanced, between about 1300 and 1850 A.D.. |
| Lutz spruce | A named hybrid spruce (Picea X lutzii). The hybrid is between coastal Sitka spruce (Picea sitchensis) and the continental white spruce (P. glauca). Lutz spruce indicates transitional ecological conditions between continental and maritime climates. Few places on the forested coast of North America contain a gradual transition between the two climate regimes, mountain ranges usually separate the two forests. On the Kenai Lowlands this transition region is extensive, and extensive stands of Lutz spruce occur. |
| Macro-invertebrate | An invertebrate (Insect or worm- an animal without a backbone) that you can see without a microscope. |
| Map component | A single, basic mapping unit building block. Map Components, with naming rules, are used to build Map Unit names for individual wetland polygons. If a polygon consists of only a single component (e.g. a kettle pond: K1) then a Map Unit can be equal to a Map Component at that polygon (K1 in the example). |
| Map unit | The name given a wetland polygon. Can be made up of one or more map components. |
| meander | Large bend in a river or stream |
| meander scroll | An arc-shaped feature on the landscape a river or stream channel once occupied. |
| medial | Middle |
| meter (m) | 3.3 feet |
| micro-topography | Uneven ground on a relatively small scale, usually the high spots are about a meter (3 feet) higher than the low spots, and only a couple of meters across. |
| modified moraine | A moraine changed by subsequent erosion. |
| modified terrace | A terrace changed by subsequent erosion. |
| Mononomial | Having a single name. Here, meaning a map unit composed of a single map component. |
| monotypic | Consisting of a single species |
| Moosehorn moraine | A moraine on the Kenai lowlands of a specific age, ending about 15,000 years ago, at the begining of the final glacial advance. Moosehorn moraines are large and relatively "fresh"- they haven't had much time to erode. |
| moraine | A pile of rocks left behind at the margin of a receding glacier. Moraines are of three basic types: terminal, at the end of a glacier; lateral, alongside; or medial, where two glaciers come together. |
| morphology | Structure |
| Naptowne glaciation | The most recent, least extensive glaciation. Made up of several glacial advances and retreats. Much of the current landscape is dominated by features left behind after this glaciation receded. |
| National Wetlands Inventory | The National Wetlands Inventory (NWI) of the U.S. Fish & Wildlife Service produces information on the characteristics, extent, and status of the Nation’s wetlands and deepwater habitats. |
| ombrotrophic | Fed only by precipitation, not by water draining from the surrounding landscape. |
| organic material | The accumulated remains of plants, mostly. Plant remains accumulate where production exceeds decomposition; this typically occurs, on the Kenai Peninsula, not because production is so high, but because decomposition is low. Decomposition is low because of several factors, but primarily because oxygen is in short supply because soils are saturated. Therefore, accumulated organic material indicates a wetland. |
| Overstory | A plant layer taller than another. In an alder stand, for example, alder could be the overstory over shorter a horsetail layer. Usually refers to a tree layer. |
| Oxbow | An abandoned stream channel bend that is now a lake (or a lake filled in by a peatland) in the shape of a crescent. |
| oxidized | In this case, combined with oxygen- specifically when organic material, which is mostly carbon, is decomposed by micro-organisms into carbon dioxide (and other compounds). |
| palustrine | Freshwater; "of the marshes" |
| Patterned Fen | A peatland with a distinctive net-like pattern of low peat ridges topped by shrubs or trees and elongate pools and low spots occupied by sedges. |
| peat | An accumulation of plant material, sometimes very deep. When peat is more than about 8" thick a wetland is almost always present. |
| Plant association | A group of plants found growing together repeatedly across a region. |
| plant community | A group of plants found growing together |
| plant physiognomy | The general look of a plant, such as a grass-like plant, a tree, or a shrub. |
| Pleistocene | Ice age, from about 2 million years ago to about 10,000 years ago. For the major glacier events on the Kenai Lowlands see this chart. |
| point bar | An accreting (growing) gravel deposit on the inside of a stream bend. |
| polygons | Irregular, many-sided shapes, in this case representing the smallest relatively uniform wetland area drawn on on a computer map. A single wetland is usually not uniform, and can be broken into many uniform areas; on a computer map (Geographic Information System or GIS) these uniform areas are referred to as polygons. |
| proglacial lake | A lake in front of a glacier, usually situated between the ice front and a terminal moraine. |
| Proximal | Next, or adjacent to. |
| recessional moraine | A moraine, composed of concentric arc-shaped ridges, left behind as a glacier recedes |
| recharge area | An area where the groundwater supply is recharged; where water soaks in, rather than flows out. |
| redoximorphic features | Colors in the soil that indicate water is seasonally present at the level the features are found. |
| Relict glacial drainageway | A linear feature that contained a glacial meltwater stream during the Pleistocene, but now, on the Kenai Lowlands, supports a peatland. |
| Relict Glacial Lakebed | A vast, relatively flat feature, that was at the bottom of a large ice-dammed lake during the Pleistocene, but now, on the Kenai Lowlands, supports a peatland. |
| riffle | A fast-moving section of a stream, usually over cobbles and gravels. |
| Riffle / pool morphology | A stream composed of reaches of alternating riffles, or faster rapids, and pools, with slow-moving water. |
| Riparian | The zone around rivers and streams that is more or less directly influenced by the river or stream- a floodplain is a good example of a riparian zone. |
| riser | the steep portion of a terrace; the flat portion is named the tread, as in stair-steps. |
| saline | salty. |
| salinity | Measure of saltiness; expressed in parts per thousand (ppt). Seawater averages about 35 ppt, and in Cook Inlet varies from between 11 and 32 ppt depending on location and time of year. During summer, freshwater flow from the Susitna and other rivers dilutes Cook Inlet salinity. |
| saltpanne | salty low flat area. Salts left behind after tidewater evaporates. Also spelled Salt Pans (which are also pans used for making salt by evaporating seawater). |
| sedge | a grass-like plant |
| Seismic line | A line cut by bulldozers, mostly during the 1960's for oil and gas seismic exploration. Now extensively used as snow machine and ATV travel corridors. |
| slope break | where a slope changes dramatically, as at the edge or base of a terrace. |
| soil horizon | a layer of distinctive color in the soil |
| soil series | the finest level of soil classification, roughly equivalent to species. |
| sphagnum | a specific kind of moss that usually forms deep peat. |
| spodosol | A soil taxonomic "order" with soils exhibiting distinctive layers of leaching (white or grey) and deposition (red to dark brownish-red), usually found under forests. |
| spring tide | The highest tide; of the day, month or year. |
| Strandline | Shoreline, or beachline- in this document strandline refers to a relict feature- where there used to be a beach when large glacial lake(s) occupied the lowlands during glaciations. These lines are now visible as wave-cut terraces- where the former beach waves eroded and deposited a steep terrace riser and a flat terrace tread. |
| strang | A low peat ridge |
| stratified | Layered, each layer is a stratum, the plural of stratum is strata. |
| stream reach | A section of a river or stream. |
| succession | The change, through time, of plant communities on a site, usually following disturbance. |
| Suppressed trees | Older, slow growing smaller trees in the forest understory whose growth are slowed by the larger trees around them. |
| tarn | a small, high- elevation lake. |
| tephra | volcanic ash |
| terrace | a stair-step like feature, which can be very large, consisting of a riser- the steep part, and a tread, the flat part. South of Clam Gulch, where glaciers from across Cook Inlet or Kachemak Bay abutted the Caribou Hills, then receded, they left behind a long series of terraced moraines. |
| tertiary surface | On the Kenai Lowlands, the uncommon areas that are not covered with glacial deposits, but have the older, Tertiary period (2-65 million tears ago), sediments at the surface. |
| textural discontinuity | a change in substrate texture from layer to layer. for example a layer of sand could lie on top of a layer of gravel. A discontinuity will perch a water table, even though the layer below is coarser, like sand atop gravel. This is because, before water can begin to flow into the gravel below, the sand must become completely saturated. This surprising phenomenon has been shown many times by replicating the sand and gravel between two panes of glass, then pouring water on top and then observing the resulting saturation pattern. |
| tidal gut | a stream-like feature formed by receding tides |
| till (glacial till) | A general term for the rocks and material left behind after glacial retreat. |
| toe-slope | the slightly sloping area below a foot-slope, and above a flat. |
| tussock | A thick clump of grass, or grass-like plant. |
| Type | When referring to plants, a plant community, which is: a group of plants found growing together. |
| underfit stream | a stream occupying a valley carved by a much larger stream- on the Kenai, generated where once larger glacial meltwater streams are now absent, as their glaciers are now completely melted. |
| understory | the plants living underneath the canopy of taller plants- usually refers to the plants growing under a tree canopy. |
| vascular plant | a plant with a certain kind of tissue for conducting water; not a moss or lichen. |
| Upland | an area that does not meet the criteria defining a wetland in the 1987 Wetland Delineation Manual (Environmental Laboratory, 1987); i.e. the opposite of "wetland". |
| water table | the first place you hit water when you dig. usually refers to a relatively stable level, and not just a temporary puddle after it rains. |
| watershed | the land around a stream, river or other body of water that catches rain and snow. All the water falling into the area eventually can drain into the water body. |
| wetland function | how a wetland works on the landscape, irrespective of any values we place on those workings. |
| Wisconsin glacial age | about 125,000 to about 10,000 years ago, the last major glacial age, made up of two major glaciations (early and late), which in turn are made up of many glacial advances and retreats. |
| woodland | an open forest with tree cover not exceeding 10%. |
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Introduction and Key to Plant Communities |
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| Contact: Mike Gracz Kenai Watershed Forum Homer Field Office Old Town Professional Center 3430 Main Street Suite B1 Homer, AK 99603 907-235-2218 |
The
Alaska Natural Heritage Program
Environment
and Natural Resource Institute
University of
Alaska, Anchorage
707 A Street, Suite 101
Anchorage, Alaska 99501
11 December 2006 17:49 |