Brackish  an area of a waterway where salt water is diluted by freshwater, or marine water has traces of fresh drinking water dispersed among the heavier salt water. Ocean water is typically 33 parts per 1000 [or 3.3%] of sodium chloride diluted in the H2O. Oceans are filled with salt water of variable concentrations above 3.3% salt (NaCl) or sodium chloride.
        Ecotone is 
          an area where a perceivable number of species from two or more different and adjacent  biological communities reside or migrate through a shared area and thus there is an increase in either numbers of creatures or the diversity of different species overlapping because the conditions of the ecotone are a mixture of the neighboring plant, bacterial, and fungal associations that sustain the animal life of this mixing zone. Oak-savannah woodlands, and estuaries are two examples of ecotones.
         
         Oak savannah woodlands are a mixture of species from grasslands and forests.
 Oak savannah woodlands are a mixture of species from grasslands and forests.
        
        Edge 
          effect is 
            the perceived increase in either numbers of species or populations along 
            the borders of two adjacent ecological communities or living systems 
            (biomes), or biotic communities because species from each of the adjoining 
            habitats have a greater number of niches to exploit. Areas where forests 
            and prairies meet, estuaries, or where temperate and tropical savannah 
            grasslands converge and overlap.
        Equilibrium
        MacArthur and Wilson's 
          species equilibrium model predicts that 
          species diversity will increase with island size and with proximity 
          to a mainland. 
         
          Field experiments 
        have supported the model.         
           
                      
        Indicator 
          species those 
            animals and plants that reveal best the conditions of the habitat, or 
            alert land or water managers to the quality of ecological conditions. 
          
         
          Birds are excellent 
            indicators of conditions can serve as an early warning of damage to 
            a community because they reproduce seasonally and feed from a wide 
            variety of foods from fruit and seeds to insects, amphibians, fish 
        and small mammals that are all herbivores.               
        inertia, 
          the tendency of something to stay in motion, or at rest, unless acted 
          upon by an external force.
        Insolation, not insulation, is the amount of solar radiation that strikes a particular position in any place. Insolation refers to the amount of sunlight falling on the earth. Or,  the solar energy received at the Earth's surface. Only a fraction of the insolation is absorbed, some of it reflects into space from opaque, or shiny surfaces. 
        Intraspecific 
          competition 
          the struggle between members of the same species who require the same 
          scarce resources, such as among elephants, bears, wolves or panthers.            
        The more the niches 
          of two species overlap, such as those of lions and wild dogs, the greater 
          the degree of interspecific competition. 
          
        irradiance is the amount of solar radiation available to be acquired by plants or instruments in a particular location. The amount of light --electromagnetic vibrations-- or radiant energy incident on a given area of surface in a given amount of time, measured in Watts per square meter. The initial measure of available resources for production in a natural system. 
          
         
          Keystone 
            species is an animal 
            so central to a food web that its demise sends a ripple effect 
            through an ecosystem. Examples are alligators, gopher tortoises, sea 
            otters or beavers whose behavior or centrality to feeding relationships 
            in a biotic community influence the integrity of food webs. This means 
            many other creatures depend on these species existence for their survival.          
          
        
        Native 
          species are 
            those creatures whose ancestry are found in and are thus endemic to 
          the place they currently inhabit. 
        The introduction 
          of nonnative species, which are creatures 
          from habitats that are remote from the new place they inhabit can lead 
          to invasive exotic species crowding out native species This accounts 
          for kudzu vine taking over southern US forests, skunk vine (Padera sp.) 
          crowding out central Florida vegetation, or Japanese honeysuckle in 
          New England.        
        
Precautionary 
                      principle in the absence of complete knowledge or perfect predictable 
                      certainty, actions taken to disturb an ecological system, in say the 
                      extraction of resources, should be done in such a way as to reduce the 
                      risks of damaging the system. Thus by limiting the harm done to keystone 
                      species, or reducing interference with the turnover of scarce nutrients 
                      or not diminishing the supply of those characteristics that act as limiting 
                      factors, careful use of resources can enhance ecological integrity. 
                      
        
The use of extraordinary 
                            care, due to extreme uncertainty, in the use of valuable, needed and 
                            vulnerable resources. These actions may include adversely affecting 
                            endangered species, overgrazing of grasslands, over fishing, or the removal 
                            of too much timber, soil, or instream water flow in areas of critical 
                            habitat concerns such as may exist in ecologically endangered lands.
        
Predation 
          is the eating of another species by a predator which benefits a predator 
          at the expense of its prey. Carnivores feed on mobile prey;  herbivores 
                                  feed on plants. Predators have 
                                    evolved a variety of ways to increase their chances of finding food, 
                                  and prey have evolved various ways to defend themselves against or avoid 
          predators. 
        
        Productivity
        Production is the amount of energy available when converted by plants and bacteria into food, fuel, forage or fiber by photosynthesis of chemosynthesis.  
        

        A comparison of grassland productivity with different communities and their divergent potentials for producing living matter called biomass as measured in tons of dry-weight material accumulating over the course of a year.
        
         PV- photo voltaic, photovoltaics, is a bit of a "jargon" term experts use for solar electricity to keep the hoi polloi from understanding what they mean. 
        
          The photo-electric effect was discovered by Albert Einstein in 1905 in a paper where he described the frequency of radiation to cause certain atoms' electrons to become so agitated or energy enriched that they move away from their "mother" nucleus when exposed to ultraviolet or stronger forms of electromagnetic photons. Hence the streaming electrons form a current of energy. 
          Photo stands for the photon of light quantum and voltaic, from volt the measure of electrical charge (force) derived from the behavior of the electrons when exposed to ionizing radiation. 
           
        
        Resource 
          partitioning or the division of a habitat into zones for predators 
          to exploit, or time periods during which otherwise mutually exclusive          demands on a resource may be satisfied for two competing species. The 
          division of the range, or the exploitation of niches at different times 
          may enable species with similar niches to coexist.
        
      
       
        With primary succession, 
          pioneer species colonize an area. 
        
        Over time, pioneer 
          species, such as, grasses, or r-strategists may be replaced by early 
          succession plant species, such as brush, bushes, or mixed grasses 
          (greater diversity) and willows after which these and related species 
          may be replaced by mid successional plant species, 
          such as pine trees, oak forests, or sycamores.
        These species can 
          give way to late successional plant species 
          such as maples, hickory, walnut or other hardwood associations further 
          increasing the diversity of trees and selecting for k-strategists. However, 
          research indicates that we cannot predict the course of succession or 
          view it as progress toward an ideally adapted climax community.