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Conservation status   [ Ecology ]

Dictionary of botanic terminology - index of names

     
  An estimation of the rarity of a species of flora and fauna. The smaller the population, the rarer the species is, and the more critical the conservation status  
     
The conservation status of a species is an indicator that tells us of the possibility of the species to continue to survive. The conservation status designates an estimate of extinction risk.
Determining which plants and animals are thriving and which are rare or declining is crucial for targeting conservation towards those species and habitats in greatest need.
Many factors are taken into account when assessing the conservation status of a species: not simply the number remaining, but the overall increase or decrease in the population over time, breeding success rates, known threats, and so on.

The best-known worldwide conservation status listings are the Red List of IUCN (International Union for the Conservation of Nature) and the appendixes  of CITES  (Convention on International Trade in Endangered Species) but many more specialised lists exist.
All these organizations conduct field studies and population surveys and gather information on animal and plant populations from local sources. By coordinating with many other groups, they determine how many individual animals or plants of a certain species there are in the world. This is usually an approximation, not an exact number, because it would be hard to be absolutely sure that every single individual was counted.
Once the number of the population has been determined, then that species is given a term to describe its status, such as "endangered” or "threatened,” although the different agencies may use different terms.

IUCN Red List
It identifies and documents those species most in need of conservation, according to internationally accepted criteria. The primary categories, with an indication of the qualifying criteria, are:
 
  Extinct No reasonable doubt that the last individual has died.
  Extinct in the wild Survives only in captivity
  Critically endangered Facing an extremely high risk of extinction in the wild..
  Endangered A species facing a very high risk of extinction that is likely to become extinct in the near future
  Threatened Facing a high but not imminent risk of extinction in the wild
  Near threatened likely to qualify as threatened in the near future
  Common: widespread and abundant.
  Unknown need more data to be able to evaluate, or still needs to be evaluated

CITES appendixes

  CITES Appendix I Species threatened with extinction that are or may be affected by trade.
  CITES Appendix II Species that are not necessarily now threatened with extinction, but may become so unless trade is strictly controlled.
  CITES Appendix III Species that a country feels needs protection, regulating, and controlling trade to prevent exploitation.

 

     

 


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Holdfast roots  [ Botany  ]

Dictionary of botanic terminology - index of names

 
     
  Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.  
     
Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans),  develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994
   

 

 

 

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