I don't know if there is a quantitative index of the sort you are looking for, but IUCN (see their webpage) has stuff in habitats as well as species. If you have a high proportion of rare and endemic species, I would go for "biodiversity hot spot".

I don't know if there is a quantitative index of the sort you are looking for, but IUCN (see their webpage) has stuff in habitats as well as species. If you have a high proportion of rare and endemic species, I would go for "biodiversity hot spot".

I don't think there is such concept to differentiate different "level" of Protected Areas. As at first to be considered as a PA, an area need to have high value in biodiversity/culture and often home of several endangered/rare species.

If a habitat/area is being threatened and is also home of endangered species then I believe it will be classified as "hot spot".

There is a difference between level of protection to manage protected areas based on value of biodiversity, threats and disturbance levels.

biodiversity hot spot   or 

Key biodiversity area

they both are utilized but not quantified for what I know

I do not know indices to compare protected areas based on the number of rare / protected species but considering the diversity in general. When areas show a certain complexity and therefore a high number of species will be considered "Hot spots”.

Therefore the presence of endangered species involves careful management and promotes the area at high rates of protection.

This is an interesting question; I think there is not a proposed terminology for such areas. Maybe a good term would be key protected area, as proposed by Giacoma

This is an interesting question. I am in favour of "Key Protected Area". Needs more thinking. 

This is kind of difficult question to be answered. Of course, you should look for IUCN protected areas data, then you should also think about the species rareness categories again from IUCN. From the other side, if the area is containing very rare or endangered species on global level then it is surely should go for higher ranking. And if it is on regional level then it should go for next level etc. Also different countries have different approaches to classify PAs according to species richness and rareness, and land- and seascape uniqueness.

The comments above cover your question. Here in Scandinavia we have used the term "Key biotope"  for a variety of biodiversity hot spots - not necessarily for protected areas, but also areas that should be carefully administered - and practically a kind of protected area under the land owners free responsibility.

At landscape levels the term "high conservation value areas/forests" are also used; mainly for Russian taiga forests.

How about a 'critical protect area'?

I would call it a Keystone Ecosystem.

I would call it wildlife sanctuary

"Protected area" is a legal designation of the land, whether local or national.  It can be national park, forest reserve, wildlife refuge, whatever.  It may or may not contain species of conservation interest.

Priority Conservation Areas for Endangered Species 

Sanctuary.

Priority Conservation Area for Rare and/or Endangered Species

Hello everyone, thank you for your help.

At the end I've used the term: 'ENDANGERED SPECIES HOTSPOT';

It could be considered as a sanctuary of regional biodiversity.

Roberto I would like to propose a slight adaptation: Threatened Species Hotspot. This I say since, the term "endangered" is associated for many years now with one of the categories of threat status (IUCN, US blue lists etc) and Threatened encompasses all "that are threatened" (i.e. Critical, Endangered and Vulnerable). I like the idea of hotspot.  Good luck with this!

Thank you Stamatis...I perfectly agree, threatened is more appropriate also because it can include IUCN L.C and VU categories. I'm assessing MPAs so hotspot I believe is also appropriate

roberto 

Biologically intense area

"Hotspot" is already a defined term http://www.nature.com/nature/journal/v403/n6772/full/403853a0.html so I think some caution needs to be applied before using it in your context.  And, as this paper by Possingham and Wilson points out, there are various metrics and some confusion about how to define hotspots:

d.yimg.com/kq/groups/17178742/1615406559/name/Cr%2525C3%2525ADtica%252Ba%252Bhotspots.pdf

So I think: hotspot is a good candidate, so long as it meets at least one of the published definitions. However, recall that the definitions are usually applied to regional-scale biodiversity, rather than to protected areas within those regions. So if your protected area is already in a mapped biodiversity hotspot, then calling it a hotspot is redundant.

If you are looking for quantitative measures for comparing existing protected areas, then there are a number of approaches available, like this one: http://www.sciencedirect.com/science/article/pii/S0006320704001454 or C-Plan (based on MARXAN) (which in South Africa uses the terminology Critical Biodiversity Area and Ecosystem Support Area for various categories of land cover).  There is also the Biodiversity Intactness Index proposed by Bob Scholes and R. Biggs http://www.nature.com/nature/journal/v434/n7029/full/nature03289.html

Finally, there are quantitative methods used to delineate the regional hotspots themselves; once again, I'm sure that the techniques could be scaled down to comparing protected areas.

So, in summary, "hotspot" is your most likely candidate, but evaluate it cautiously so as not to create yet more confusion with the term. If the reserve falls outside of one of the global hotpsots, but is regionally important relative to its surrounding biodiversity, you may want to look at a term like "local hotspot" or some other defining adjective.

EDIT: If the Possingham & Wilson link doesn't work for you, search for Possingham HP and Wilson KA. 2005. Turning up the heat on hotpsots. Nature 436: 919-920

Here's another useful paper on the definition of hotspots

http://planet.botany.uwc.ac.za/NISL/Biodiversity/Attachments/Reid1998.pdf

Biodiversity hotspot or ecologically rich can be used. Sometimes the number of endangered or threatened species is not always indicative of highly diverse areas. Think of islands for example. 

I agree with Alan, the term 'biodiversity hotspot' is an already defined term (see Mittermeier et al 2011).

You may want to check Birdlife International's website to see if the site is a Key Biodiversity Area (the guidelines for defining such an area have been recently updated), an Important Bird Area (IBA) or Endemic Bird Area (EBA). Other spatial classifications for areas of importance for biodiversity include: Important Plant Area (IPA) and Area of Zero Extinction (AZE).

I beleive AZE may fit your original post the best - as it will by definition incorporate rare and endangered species.

More info on AZE here: http://www.biodiversitya-z.org/content/alliance-for-zero-extinction-sites-aze

Area of Zero Extinction (AZE) thanks, hadn't heard of it before! Saw website now I understand, but hey, its a really childlike phrase...little evolutionarily incongruous...to say "zero extinction". Ok.  

To Edward: thank you, however the Marine Protected Areas we are working on do not fullfill the three AZE criterias...we will, however, get some usefull info from their view.

Roberto