A Floristic Provence is a geographic area with a relatively uniform composition of plant species. Adjacent Floristic Provinces do not have a sharp boundary, but rather a blurred one. Instead there are transitional areas in which many species from both regions overlap.
PLANT COMMUNITIES
Proximity to the ocean, slope aspect, exposure, surface water, & elevation are the primary factors affecting the local climate. These factors create groupings of plants that grow on the Earths surface that are noticeably different from each other. Plant communities often have one or more dominate species that are common to that area. These are the Indicator Species.
ELEVATION EFFECTS ON VEGETATION
The atmosphere is like a blanket. At low elevation the insulating blanket of air is thick, while at high elevations it is much thinner. This means that the higher up we move in elevation the colder it gets. In addition high elevation areas tend to be wetter than low elevation areas.
SOIL AFFECTS ON PLANT COMMUNITIES
Soils have a great affect on what type of plants grow on them. The majority of plant nutrients come from the soil. Soil texture & drainage are important factors in the soils ability to retain moisture. Availability of ground water & organic content are also important factors.
SOIL AFFECTS ON PLANT COMMUNITIES
Some soils are hostile to plant growth, even toxic. Some plants exploit this niche. They evolve certain mechanisms to cope with the difficulties. The successful plants are rewarded with having little competition.
SLOPE ASPECT
Slopes that face north cast more shadow to the earth below. North slopes also have more shade. Southern slopes are exposed to the most intense sunlight. This difference in sunlight intensity makes north slopes moister & cooler. Southern slopes are hotter & dryer. The plants growing on a sunny slope are different from those on a shady one.
INDICATOR SPECIES
An indicator species is any organism that characterizes the environment in which it lives. Many times these species are the Dominate or Climax species. Dominant species are the most common species on a region. Climax species are often the largest & most complex.
ENDEMIC PLANTS
Plants that are found nowhere else in the world except in their local area are known as Endemic. Often times endemic plants are highly specialized to live in a special niche in the environment. Many of these plants are threatened or endangered.
NATURALIZED PLANTS (WEEDS)
Naturalized plants are plants that are not native to a particular area but grow there as if they were native (sometimes even better). These plants often have no natural enemies in their new home & can aggressively outcompete native species. Non native species increase the potential for fire.
SUNSET CLIMATE ZONES
Sunset Magazine developed a climate zone system that provides a more realistic picture about a local climate than the standard USDA climate zones. Sunset zones factor in all climatic conditions. The zones are organized from coldest to warmest zone 1 being the coldest & zone 24 being the warmest.
