PHYSIS. A world catalogue and classification of habitat types. OBJECTIVE introduce diagnosable communities, in parallel with species, into conservation applications. Introducing habitats in conservation applications allows:
A world catalogue and classification of habitat types
introduce diagnosable communities,in parallel with species, into conservation applications
Integrator properties of communities:
the South American continent can be adequately covered by a total of about 10 000 habitat type units, a much lower number than that of species
there is a better correlation between the local distribution of habitat types and that of species groups than between the respective distribution patterns of various species groups.
Description of protected areas
Definition of conservation policies
Selection and evaluation of protected areas
Lists of habitat types present, like species lists, help characterising conservation areas
Lists of priority habitat types can be incorporated in conservation legislation, in particular in appendices or resolutions parallel to those that cover species. Designation of protected areas included in legally-based networks and conservation or management rules can be related to those lists.
Protected area networks can be designed to insure complete coverage of habitat types identified in a geographical space, in parallel with that of target species.
With habitat types, as well as species, part of the motivation for designation of protected areas, management guidelines can be established to meet the requirements of ecological processes and of the “silent” biodiversity in addition to those of target, key and umbrella species.
Definition of habitat
Definition of elementary units
World integrating system
Upper levels of classification
In common usage, a habitat is "the natural home of an animal or plant" (Collins). Integrating these definitions over all species, for each of which the habitat is the sum of the abiotic environment and of all other species present, a habitat can be defined as "a topographical expanse homogeneous in its physical and biotic components at the scale of the phenomenon studied" (Blondel, 1979, 1995). Thus, a habitat is a three-dimensional spatial entity that comprises at least one interface between air, water and ground spaces, it includes both the physical environment and the communities of plants and animals that occupy it.
The definition of habitats depends on the scale at which it is considered. The level of resolution that has been used in the PHYSIS typology is that of the ecological requirements of small vertebrates, large invertebrates and vascular plants. A few units, clearly labelled, have been introduced to permit rendition by the use of single codes or combined codes of the ecological requirements of larger organisms or of the most mobile ones among the smaller ones.
A unit in the PHYSIS typology is a habitat type, thus a characterisation of a collection of spatial entities equivalent as habitats, sufficiently alike in abiotic conditions, physiognomy, composition of plant and animal communities, to play similar roles in nature conservation. Two habitat types are distinguished if the communities they support are sufficiently distinct to confer to them a different significance in the preservation of sensitive species. For plant communities, phytosociological criteria are often available to assess degree of divergence and its relevance to sensitive species. For animal communities, data are often lacking for the groups most in need of habitat conservation rather than species-specific programmes. Physiognomy, plant dominance, ecological conditions and biogeographical parameters, including geographical separation, are used to assess distinctness.
In practice, within the PHYSIS system, elementary units are chosen so as to correspond to clearly recognisable entities. Their definition insures compatibility with local habitat or vegetation schemes while their hierarchical positioning preserves a potential for cross-boundary and intercontinental comparisons.
All habitat classifications use similarities in physiognomy, abiotic conditions, plant community composition, plant dominance, plant community succession and, sometimes, animal community composition to combine elementary units into collective entities of successively higher rank. Contrary to classical species taxonomy, habitat classification cannot claim to include a "natural" system of ordering based on the best available perception of phylogenesis. Thus, the priority given to the various criteria and the ensuing classifications are necessarily a matter of choice. The PHYSIS habitat classification uses1. large-feature physiognomy2. plant-community composition3. factors underpinning animal-community composition..
The integrating system rests on the matrix-use of two existing sets of upper category describers, the biotic realms of the IUCN bio-genetic reserve system, and a list of upper units of habitats of global application. Upper units of habitat within any realm are then designated by combination of a realm digit in the third rank to the left of the decimal point with a biotope class number of two digits in the second and first ranks. Lower divisions, characterised by digits to the right of the decimal point, are specific to each realm and not necessarily homologous between realms. There is, however, no reason not to preserve the lower unit hierarchy as far down as possible for types of habitat with more evident cosmopolitan homologies, such as marine habitats.
The southeastern Asian continent south of the northern borders of Pakistan, India, Nepal, Bhutan, Sikkhim, Burma, Thailand, Laos and Vietnam. The southeastern Asian archipelagoes and seas, southeast to New Guinea, the Bismarck archipelago and Bougainville. The Laccadives, the Maldives and Chagos, the Andaman and Nicobar Islands.
For practical reasons, the limits of realms are chosen so as to avoid placing political entities in two realms. In particular, the southeastern limits respect the political borders of Papua New Guinea. They are more usually placed along Wallace's Line, at the southeastern edge of the Asian continental plate, or, sometimes, as by Udvardy, along the northeastern edge of the Australian continental plate. Neither arrangement is entirely satisfactory. In addition, New Guinea, placed in an Oceanian Realm by Udvardy, is climatically, ecologically and, in part, at least, floristically more closely related to southeast Asia, faunistically, to Australia.
1 Coastal and halophytic communities
11 Ocean and seas, marine communities
12 Sea inlets and coastal features
13 Estuaries and tidal rivers
14 Mud flats and sand flats
15 Salt marshes, salt steppes, salt scrubs
16 Coastal sand dunes and sand beaches
17 Shingle beaches
18 Sea-cliffs and rocky shores
19 Islets, rock stacks, reefs, banks, shoals
1A Coastal agrosystems
21 Coastal lagoons
22 Standing fresh water
23 Standing brackish and salt water
24 Running water
31 Temperate heath and scrub
32 Sclerophyllous scrub
34 Steppes and dry calcareous grasslands
35 Dry siliceous grasslands
36 Alpine and subalpine grasslands
37 Humid grasslands and tall herb communities
38 Mesophile grasslands
3A Tropical grasslands
3B Tropical shrublands
3C Tropical alpine communities
41 Temperate broad-leaved deciduous forests
42 Temperate coniferous forests
43 Temperate mixed forests
44 Temperate riverine and swamp forests
45 Temperate broad-leaved evergreen forests
46 Evergreen rain forests
47 Semi-evergreen rain forests
48 Monsoon forests
49 Tropical montane forests
4A Tropical swamp forests
4B Dry tropical woodland
4C Mangrove forests
51 Raised bogs
52 Blanket bogs
53 Water-fringe vegetation
54 Fens, transition mires and springs
62 Inland cliffs and exposed rocks
63 Eternal snow and ice
64 Inland sand-dunes
66 Volcanic features
71 Polar deserts
72 Continental deserts and semi-deserts
73 Subtropical deserts and semi-deserts
74 Cool coastal deserts
81 Improved grasslands
83 Orchards, groves and tree plantations
84 Tree lines, hedges, rural mosaics
85 Urban parks and large gardens
86 Towns, villages, industrial sites
87 Fallow land, waste places
88 Mines and underground passages
89 Industrial lagoons and reservoirs, canals
93 Wooded steppe
94 Wooded tundra
95 Treeline ecotones
97 Wooded deserts and semi-deserts
Temperate forests dominated by broad-leaved sclerophyllous or lauriphyllous evergreen trees, or by palms. They are characteristic of the mediterranean and warm-temperate humid zones, with a few representatives in transition areas to tropical forest and subtropical desert zones. In the Indo-Malayan realm, they are limited to Himalayan evergreen oak forests and to lauriphyllous warm temperate forests of Sino-Japanese affinities distributed from northern Myanmar to northern Vietnam.