Important Arable Plant Areas

Important Plant Areas (IPA)

A key focus for plant conservation is the Important Plant Areas (IPA) programme. It is designed to identify a network of the key botanical sites across Europe. The concept has now been widely adopted in Europe, and is increasingly finding favour more widely across the globe as a significant mechanism for identifying exceptional botanical sites to allow conservation action to be prioritised.

This IPA mechanism is also fundamental to the delivery of Target 5 of the Global Strategy for Plant Conservation, which calls for the protection of 50 per cent of the most import areas for plant diversity assured by 2010.

The definition of an Important Plant Area (IPA) is a natural or semi-natural site exhibiting exceptional botanical richness and/or supporting an outstanding assemblage or rare, threatened and/or endemic plant species and/or vegetation of high botanical value.

There are three basic principles for IPA identification:

Criteria A: The site holds significant populations of one or more species that are of global or European conservation concern.
Criteria B: The site has an exceptionally rich flora in a European context in relation to its biogeographic zone.
Criteria C: The site is an outstanding example of a habitat type of global or European conservation and botanical importance.

Important Arable Plant Areas (IAPA)

There have been improvements in the quality and extent of knowledge of the status of species on arable land, however they remain a difficult group of plants to survey and keep account off. This is largely due to the sites mainly being on private land presenting access problems. Arable plant population are also effected greatly by the cultivation timing and cropping system that is adopted at a site leading to fluctuations in variety of species from year to year. Climatic conditions will also impact.

There are have been a number of studies that have looked to identify the richest areas for arable plants across Britain, which have been useful in identifying general areas where conservation management would have the greatest impact. However the analyses is still insufficient to really target action at a farm or even field level. Therefore the need for a clear methodology that can be used to identify key sites is urgently required. This will work to ensure that rare species and species-rich assemblages are conserved in there natural setting.

The method for assessing arable sites is based on the presence of threatened species and/or exceptional assemblages of arable species derived from the wider Important Plant Areas model. The criteria present thresholds that should allow interested groups to instantly assess the value of a site – be it of county, national or European importance.

There are three different criteria in which a IAPA can be identified, based on the presence of;

(a) particular threatened species
(b) exceptional plant assemblages
(c) priority habitats of particular importance to botanical science (inappropriate to use at present due to arable plant communities being to poorly studied)

Site Status

Whilst the European IPA process selects sites of international importance, the IAPA methodology highlights arable sites in the UK of three levels of importance:

Sites of European importance: sites that are identified as being of European importance on account of their arable vascular plant interest alone, and which should be considered for inclusion within the UK’s IPA contribution to the European network of IPA’s.

Sites of UK importance: additional sites of national importance of their arable plant interests.

Sites of county importance: a shadow listing of sites that are of high regional importance which, may with further detailed recording, prove to be of national importance.

Criteria categories

Criteria A – threatened species – allows for the selection to sites based solely on the occurrence of threatened arable species listed in recognised national, European or global red lists. At the present time no British arable plant species are recognised as threatened at a European level, so no arable sites here currently qualify at the European level under criteria A.

Criteria B – outstanding assemblages – utilises the same methodology for identifying sites of country, UK and European importance, a scoring system that tallies the weighted individual score of each of the species present according to their rarity and decline across Britain.

The basic listing of arable species has been drawn from PLANTATT: Attributes of British and Irish Plants, which provides the most comprehensive listing of species characteristic of arable land currently available. There have been a few additions to the list of species considered to occur occasionally as characteristics members of the arable flora.

Individual species scores – ranging between 1 (common) to 9 (rarest and most threatened) – have been assigned to arable plants based on:

(i) their current occurrence within 10-km squares; and/or
(ii) their recent decline; and/or
(iii) their current species threat status

The scoring categories are as follows
9 – Threatened – Critically Endangered
8 – Threatened – Endangered
7 – Threatened – Vulnerable
6 – New Threatened
5 – Additional Nationally Scarce: 16 to 50 10-km squares; or 51 – 100 10-km squares, change index less than –1.0
4 – Additional Nationally Scarce: 51 to 100 10-km squares, change index greater than –1.0
3 – Species of local concern; 101 to 500 10-km squares
2 – Species of local concern; 501 to 1000 10-km squares
1 – Species of local concern: 1001 to 1500 10-km squares, change index less than 0.0

This outstanding assemblage assessment method is based on the cumulative total of the weighted scores of species present at each site, allowing the comparison of the relative nature conservation value of different sites. Provisional threshold scores have been proposed for sites of county, national and European importance, which in tern recognises variation in species abundance on different soil types.

	Chalk and limestone derived soils (excluding clays)	Clays	Sands and freely draining acidic soils
European importance	90+	70+	70+
National importance	45 – 89	30 - 69	35 – 69
County importance	30 – 44	20 - 29	20 – 34

Example:

A site with Shepherds Needle (9), Corn Marigold (7), Prickly Poppy (7) and clay soil

The site would be an IAPA of National importance under Criteria A as Shepherds Needle is Critically Endangered and Corn Marigold and Prickly poppy are both Vulnerable.

With an accumulative score of 23 on clay the site would be classified as county importance under Criteria B

For full details on the IAPA process and species listing download the full report "Important Arable Plant Areas - Identifying priority sites for arable plant conservation in the United Kingdom