Abiotic components: In biology and ecology, abiotic components, or abiotic factors, are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems.

Some Definitions

Acidic: a description of soils or water that has a pH less than 7. Few plants survive in strongly acidic conditions, such as those created by weathering minerals or rocks that contain sulphide minerals (e.g., pyrite FeS2) . Decomposition of plant litter can also generate acidic soil. Peat bogs are acidic. Acidic soils also form under conifer, cedar, and oak trees.

Alkali Flat: a name for a dry lake, or playa, whose floor is covered by high concentrations of precipitated dry alkali compounds, as sodium sulfates and carbonates. Such a feature is usually a very shallow depression, or basin, that is generally considered to have contained standing, surface water. That body of water evapourated faster that it was recharged. Where moisture is present from recent precipitation, surface runoff, or groundwater, the water eventually evaporates leaving a layer of alkali compounds or minerals. If the floor is covered with salt (halite: NaCl), it is called a salt flat or salina. Alkali flats are very limited or often devoid of vegetation due to the high pH and saline concentration.

Alkaline: the opposite of acidic, characterized by a pH greater than 7. The most common cause of neutrality and alkalinity is the presence of the element calcium, generally present in the mineral calcite (CaCO3), that is leached from the rock limestone or dolomite. Calcium may also be derived by the weathering of common rock-forming minerals, such as plagioclase (CaAl2Si2O8) and pyroxene [(Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6].

Alvar: Alvars are globally rare, naturally open habitats with either a thin, or no, covering of soil on a base of limestone or dolostone. Alvars experience seasonal extremes from spring and fall flooding to summer drought. Most alvars occur in northern Europe and around the Great Lakes in North America. Canadian alvars also occur in away from the Great Lakes in Ontario, Manitoba, Newfoundland and Labrador, Northwest Territories, and Quebec. In the United States, alvars occur in Michigan, Ohio and Wisconsin. Alvar habitat supports unusual flora, insects, and birds. The rare plants are generally adapted to tolerate, and even thrive, in the calcareous alvar conditions. Lichens and mosses are common. Trees and bushes are absent and where present, may be strongly stunted. Fire may help prevent overgrowth by forest. Karst features in the limestone and dolomite substrate, created by rock dissolution by water, may provide unusual micro-habitats for rare plants. More info: Alvar: Meaning, Definition, Explanation.

Alvar alternative names: Alvars are commonly called by different names in different countries. Some of these alternate names include: a) barren limestone terrace; b) limestone pavement; c) calcareous grassland or alkaline grassland; d) barren lands; e) pavement barren; e)

Alvar pavement: a) occurs on exposed rock (at least 50 percent); b) where soil covered, the soil is less than 2 cm thick; c) vegetation is patchy and mosses and lichens are dominant; d) is characterized by plant diversity; e) Ontario examples: Manitoulin Island and northern Bruce Peninsula.

Alvar shrubland: a) moderate to high cover of shrubs, low tree cover, which appear stunted; b) Ontario examples: Carden Alvar and Manitoulin Island.

Alvar savannah: a) rarest, least common alvar type; b) scattered tree cover ranges from 10 to 25 %, consisting usually of oak or pine; c) provides a range of habitat for wildlife, including birds and mammals, than other alvar types; d) Ontario example: Stone Road Alvar on Pelee Island.

Alvar grassland: a) supports grasses and sedges; b) vegetation is more continuous and looks more meadow-like in character; c) soil depths range from 1-10 cm; d) species vary depending on on extent of spring flooding; e) Ontario examples: Carden Alvar and Napanee Plain.

Alvar woodland: a) tree cover is the highest of the alvar types; b) conifers are common; c) often adjacent to other alvar types; c) Ontario examples: Manitoulin Island and Napanee Plain.

Alpine: a region that occurs above the the line of stunted trees and below the snow line on temperate and tropical mountains. Vegetation in the alpine zone is characterized by an absence of trees and varies greatly with aspect, the greatest contrasts being between the wet side and the dry, leeward side of the mountains concerned.

Arctic: a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Alaska (United States), Canada, Finland, Greenland, Iceland, Sweeden, Norway, and Russia.

Basicole: an older term that describes plants, which occur on base-rich substrates such as basalts and calcareous mudstones.

Bog: a nutrient poor, acidic, peat-forming, waterlogged, flat lowland. Bogs are common across the Canadian Shield. Bogs are rare across southern Ontario, where limestone rocks are abundant.

Calcicole: a plant that occurs exclusively on limestone, marble, or dolomite - rocks of > 50% CaCO3 and/or calcium magnesium carbonate (CaMg(CO3)2)) and their derived soils. I also use calcicolous plants as a description of plants that thrive or tolerate calcareous substrates.

Ecology: the branch of biology that deals with the interactions and relations among organisms and to their biophysical environment, or surroundings, which includes both biotic and abiotic components.

Ecosystem: an ecosystem is a community of living biotic organisms and the nonliving abiotic components of their environment, interacting together as a system. The biotic and abiotic components are linked together through nutrient cycles and the transfer, or flow, of energy. Energy enters the system through photosynthesis and is incorporated into plant tissue. Animals feed on plants, and on one another, and therefore animals play an important role in the movement of matter and energy through the system. Animals also influence the amount of biotic biomass present in the system. Ecosystems are controlled by external and internal factors. External factors, such as climate, control the overall structure of the ecosystem, but external factors are not influenced by the ecosystem. Internal factors, such as decomposition or species present, are controlled by the system.

Endolith: an organism that colonizes the interior of any kind of rock. The term consists of 5 subclasses: 1) Chasmoendolith: colonizes fissures and cracks in the rock connected to the surface (chasm = cleft); 2) Cryptoendolith: colonizes structural cavities within natural pore spaces within the rocks that are usually indirectly connected to the rock surface. Note, “crypto” means hidden; 3) Euendolith: penetrates actively into the interior of rocks forming channels and grooves that conform with the shape of its body, rock boring organism. Note the term “eu” means true; 4) Hypoendolith: colonizes the pore spaces located on the underside of the rock and that make contact with the soil. Note, the term “hypo” means ; 5) Autoendolith: capable of rocks formation by mineral depositation. Note, the term “auto” means self.

Fen: a type of wetland. Fens are usually fed by mineral-rich surface water or groundwater, which has a pH that is neutral to slightly alkaline. The feed waters usually have higher dissolved mineral content. Fens are usually dominated by grasses and sedges. Fens occur along large lakes and rivers where seasonal changes in water level maintain wet soils with few woody plants, and are common in the Hudson Bay and James Bay lowlands. The distribution of individual species of fen plants is often closely connected to water regimes and nutrient concentrations

Grassland: areas where the vegetation is dominated by grasses, with lesser sedge and rush. Grasslands occur naturally on all continents except Antarctica. Grasslands cover 31-43% of the earth's surface and are one of the largest biomes on Earth.

Glacial pavement: A rock surface that has been scraped by glaciers moving over it. The surface of the pavement may carry scratches and gouges created by rock fragments frozen into the base of the glacier. Those rock fragments scratched the underlying rock. The scratches are called striations if they are small and grooves if they are large. Geologists use these features to show the direction of ice movement.

Marble barrens: these are barrens that are underlain or dominated by a rock substrate consisting of marble.

Habitat: a natural environment, characterized by both physical and biological features, where a particular species lives. The species lives in that habitat because it finds food, shelter, protection, and can reproduce.

Limestone glade: Limestone bedrock glade is an herb- and graminoid-dominated plant community with scattered clumps of stunted trees and shrubs growing on thin soil over limestone or dolomite. Tree cover is typically 10 to 25%, but occasionally as high as 60%. Shrub and herb cover is variable and there are usually areas of exposed bedrock. Mosses, lichens, and algae can be abundant on the exposed limestone bedrock or thin organic soils. Seasonal flooding and summer drought help limit vegetation growth. Some references use the term alvar glade interchanably.

Limy: a term used to describe calcareous conditions, including calcareous soil and rock (e.g., limestone substrate is limy).

Neutral pH: in the middle between acidic and alkaline, having a pH = 7. Most soil in southern Ontario is naturally somewhat alkaline because of the limestone rocks. In northern Ontario, glacial soil pH can be neutral to slightly alkaline where the glaciers scraped over the limestone rocks that rim Hudson Bay and James Bay. In other parts of northern Ontario, glacial soil can be neutral to slightly acidic where the glaciers scraped over large areas of granite-rich Canadian Shied. Soils developed on peat-rich bogs, common in northern Ontario, can be acidic. Soil pH can be complicated.

pH: a scale used to indicate the degree of acidity or alkalinity of a substance such as soil. Local rock substrate and vegetative accumulation (e,g, peat) can dramatically influence local pH. Regional pH levels are influenced both by rock substrate and glacial “soils” deposited during the last ice age. Plants have preferences for acidic, neutral or alkaline conditions. Vinegar is a weak acid. Antacid tablets, such as Tums, are alkaline, which is why they neutralize stomach acids.