Print
Category: BSG WEBSITE INFORMATION
Hits: 1191

BIOGEOGRAPHY & STANDARD TERMS & REFERENCES USED BY BSG 

 

Birding Site Guide

TAXONOMY & NOMENCLATURE 

These both follow Clements 5th and 6th edition (2000-8) Birds of the World: A Checklist. For this reason scientific names are not generally given in the site account write-ups (but are always given in lists as these will probably be used in the field where the English names may differ from the field guide, or other reference source English name). If any scientific name needs to be looked up, I recommend using either Clements book, or Avibase website (see Selected Links). 

As with all ‘official’ lists there are inevitably areas of controversy, and Clements is no exception. Some of the English names seem to English birders absurd, because the characters for which the bird was named in Europe often differ to the characteristics of birds elsewhere in the world where the name has been applied. Redstart was such an example. Jaeger instead of skua seems to incite some venom from British sea-watchers, yet they seemingly do not realise that Jaeger was a Victorian word which while falling out of use where it originated, in Britain, was still faithfully retained in the New World, it is not a trendy American word! Clements list was chosen for BSG mainly because it was widely accepted, regularly updated, and closely followed the taxonomy and nomenclature of the monumental Handbook of the Birds of the World (Lynx Edicions), and so will remain a major reference for a long time to come. Of course other lists now claim to be more accurate, due to DNA sequencing, and this work threatens to upturn many cherished views about the relationships of the families of birds. This DNA work however still has a long way to go before establishing a new stable order, and so for the time being is not widely followed. 

THREATENED STATUS 

Globally threatened species have the following terms and abbreviations applied to them. These are the terms used by BirdLife International and others, including BSG. For full explanations of criteria for each threat level, consult BirdLife International’s Endemic Bird Areas of the World or their website (see Selected Links). 

NT means Near Threatened, not yet threatened but likely to be upgraded 

VU means Vulnerable 

EN means Endangered 

CR means Critical 

DD means Data Deficient 

BIOME ENDEMICS & NEAR ENDEMICS SPECIES LISTS (BENES) 

BENES lists are the only list available which cover all restricted range species, all endemics and all threatened and near-threatened species for the whole area of a biome. EBA lists only cover the area of the biome that restricted range species occur in, they do not cover a whole biome if the restricted range species do not occur throughout. This is the biggest and most important difference between EBA lists (with or without other threatened species noted) and BENES lists. There are other differences. 

EBA (Endemic Bird Areas lists, BirdLife International) are areas where 2 or more restricted range species overlap, and this may only be in part of a biome. This is because EBAs do not cover restricted range species if only one species occurs in the area. They do not cover threatened or near threatened species unless they also have restricted ranges (to be fair BirdLife list these in the text of their books and website). They do not cover biome endemics either, unless they are restricted range. Biomes are usually much larger than the 50,000km2 of the restricted range species limit. BENES lists are designed to cover all of the above for the whole biome. 

Admittedly biomes can be big, and in large biomes it is possible to eliminate many species from a possible list just on range alone. But if visiting several sites in a large biome (say the Atlantic forest) then it is far easier to start with a complete list for the biome to be visited than trying to construct a list from field guides and trip reports. Besides field guides are often out of date, especially the maps, global status is usually not given or is out of date and names and taxonomy change, along with new species being added. Every species on every BENES lists was checked for range on the most up-to-date range maps on the internet (WWF Wildfinder and NatureServe: InfoNatura) all status’s were checked with BirdLife International and all names and taxonomy made to follow Clements (and so HBW). Yes, I suffered making these BENES lists, the Amazonian Lowlands list took about 15 days work alone. Rather than leave all that work collecting dust, I decided to make it available for everyone for free on my website, I hope you find it useful. 

The areas selected for BENES lists are fairly arbitrary, a biome can theoretically be any size from a single small habitat to half a continent, so long as it can easily be recognised as a distinct region of inter-linked habitats. Extreme examples are the Dwarf Palm Cerrado of Paraguay, which occurs in only one small reserve (Mbaracayu) and nowhere else on earth, to on the other extreme, Amazonia. For definitions of a biome (and related terms) see About Biogeography. 

ABOUT BIOGEOGRAPHY 

REGIONS DEFINITIONS AS USED BY BSG 

Although it is very attractive to the human mind to divide the earth’s surface up into its larger component pieces, according to limits of such things as large land masses and seas and give these areas ‘continent’ names, it is far from satisfactory for defining the geographical limits of the earths biota. Although many animal and plant groups do have their limits of occurrence quite closely tied with the limits of the these 'continents', a very great number do not. Biogeography carves the world up a bit differently, instead of using just larger areas of land-mass and seas to divide the world, biogeography also uses the affinities of the biota of each region and groups these regions accordingly. Mexico is part of the North American continent, but its biota has very little in common with the USA and Canada but much in common with the continent of South America. For this reason biogeographers place Mexico in the Neotropical Province and not with the Nearctic Province of the USA and Canada. 

The biogeographical regions of the world are known as Regions (or Provinces), but their is no firm agreement on either their boundaries, their names or even how many there are. BSG roughly uses the following as shown on the map: Afrotropic, Antarctic, Australisia, Oriental, Nearctic, Neotropic, Eastern Palaearctic and Western Palaearctic. Biogeographical Realms are divided up in ever increasingly larger scale as follows Realm, biome, ecoregion. Each has a unique name and number classification. biomap.gif

























Just as birders argue over which list to use so biogeographers argue over demarcation lines. I am not a biogeographer, but I wanted my Regions to reflect the distribution of biological organisms by family relationship, and the Regions chosen are therefore given below. 

The Afrotropic consists of Africa east of the Fernando de Noronha, Trinidade, and South Sandwich Islands; south of Spanish Sahara, Algeria, Libya, Egypt, Saudi Arabia, and the United Arab Emirates; east of the Maldive Islands and Chagos Archipelago; and north of Antarctica. 

The Antarctic is the Antarctic continent and all areas within the Antarctic circle. 

Australasia is all lands in the southwestern Pacific region east of Talaud, Sulawesi, Sanana, Damar and Sermata Islands (Weber's Line, as employed by Neboiss, 1986), south of Mindanao, Iwo Jima, Marcus, Johnston, and Hawaii Islands, west of Easter Island, and north of Antarctica. 

Note: Oceania is sometimes considered distinct from Australasia and sometimes not. Though combined the islands have a lot of land (principal island being New Zealand) there is no continent as with other biogeographical regions, so is it valid? I don't know but I have separated it for now. Oceania would include New Zealand and New Caledonia in the West as far North as but not including the Carolina Islands of Micronesia. It would include all islands as far North as this to the East, so all the islands of the Pacific except Hawaii as far East as and including Pitcairn Island. 

The Nearctic consists of all lands east of Russian Siberia, Komandorsk Island, and Wake Island; north of Palmyra, Socorro, and St. Benedicto Islands, the Mexican states of Jalisco, Michoacan, Guerrero, Morelos, Puebla, and Veracruz, Anguila Isles and the Greater and Lesser Antilles; and west of The Azores and Iceland. 

The Neotropic consists of lands east of Pitcairn and Ducie Islands; south of the Mexican states of Sinaloa, Durango, Zacatecas, San Luis Potosi, and Tamaulipas, Andros, Great Inagua, and the Bahama and Caicos Islands; west of Cape Verde, Ascension, and Tristan de Cunha Islands; and north of South Orkney, Elephant, and South Shetland Islands. 

The Indo-Malayan consists of all lands east of Heard, Kerguelen, St. Paul, Amsterdam, Rodriguez, and Seychelles Islands and Iran; south of the Commonwealth of Independent States, the eastern Palearctic Chinese Provinces of Xinjiang and Qinghai (Schmid, 1966), Gansu, Shaanxi, Henan, and Shandung, and the island of Okinawa; west of Guam, Palau, Halmahera, Obi, Buru, Teun, and Barbar Islands and Australia; and north of Antarctica. 

The Palearctic consists of all lands east of the Russian Ural mountains and the Caspian Sea; north of Iran, Afghanistan, oriental China and Taiwan; and west of Midway Island, the Aleutian Islands, Saint Lawrence Island, and Alaska. The Western Palearctic consists of lands east of Greenland and Bermuda Island; west of Russian Siberia, Kazakstan, the Caspian Sea, Turkmen, Afghanistan, and Pakistan; and north of Cape Verde Islands, Mauritania, Mali, Niger, Chad, Sudan, Ethiopia, Yemen, The Democratic Republic of Yemen, and Oman. 

Polar regions, that is the Arctic zone and Antarctic lie at the higher latitudes and are defined by the areas where the sun can be seen for a full 24 hours in summer and not seen for 24 hours in winter. The Arctic being largely water has no land mass solely situated within this region and therefore any land within the Arctic Circle can safely be included in other Realms. 

Lets look at an example to illustrate the above points, say the Atlantic forest biome of se Brazil. This is the Brazilian Forest Realm (in the Neotropical Province) and this biome can be subdivided into several smaller biomes and many habitats. To just site 3 biomes of the Atlantic forest, there is the Atlantic forest lowlands, Atlantic forest mountains and Alto Parana Forest. These can be further defined into many ecoregions, for instance the Atlantic forest lowlands is not just a uniform forest but contains different types of forest, it may contain areas of scrub and in depressions marshes and wetlands. The Atlantic forest mountains is also composed of many habitats, these include the Araucaria pine forests, Chusquea bamboo, humid montane forest, elfin forest and paramo. All these ecoregions will have specific unique names and numbers, to find information on all the ecoregions of the world and their species look at World Wildlife Fund-Wildfinder (see Selected Links). 

There are however problems with biogeographical Realms or Provinces. A good example is Argentina, in the Neotropics. This country does not lie in a tropical region, that is between the Tropic of Cancer (in the northern hemisphere) and the Tropic of Capricorn in the southern hemisphere. Although its affinities are with the Neotropics, they are also very different, but one might argue, Argentina does not logically belong in any other Province. However it may, more accurately be placed with New Zealand, because of its shared families of plants. Many biogeographers place New Zealand in the Antarctic Realm and not in the Australian Province as might be imagined, to understand this requires the knowledge that Antarctica was not always a frozen desert but once a fertile land bridge between New Zealand and South America, whereas Australia had long since been isolated. The situation is further confused because the Australian Province is often included as part of the Oceania Province. 

The factors that play the greatest influence then in determining a regions habitats are latitude, and elevation (taken from mean sea level), climate, geology and biota. 

It may seem longitude plays a small part in this, except in relation to how far a region is located inland or out at sea. Latitude however plays an immense role, determining whether a region is seasonally hot and cold and to what degree of extremes. Altitude affects much the same as latitude, but can influence even small areas. 

MEASUREMENTS 

All measurements are metric. Coordinates are from the latest maps, or in cases of personal experience coordinates are taken from GPS (unfortunately I am on my third Garmin Foretrex 201 in 3 years!). Every coordinate on BSG is individually checked or cross-referenced for accuracy (a small minority cannot be checked), as unfortunately errors, even large ones, seemingly abound even in modern bird publications, particularly for the southern hemisphere. Generally only the arc and minutes coordinates are given to a roughly central position, with seconds used only for specific places such as entry points and buildings. At the equator each arc of longitude is 110km apart, the same as the distance between latitude lines, but the arc of longitude obviously diminishes at higher latitudes. 

Coordinates may be given British fashion, longitude then latitude or New World fashion latitude first then longitude, but either way should have a compass prefix to avoid confusion. Since the numbers are always followed by the compass point it really makes little difference. Historically, since the British Navy was the first body in the world to accurately measure longitude (using probably the world’s most accurate mechanical clocks ever made) thus establishing Greenwich as zero meridian, Britain naturally quoted longitude first, much to the chagrin of the French Parisians who had claimed the zero meridian before Greenwich. The new America nation in a show of independence, did most things opposite to the British, including driving on the other side of the road! 

Altitude measurements are in metres above mean sea level. All altitude readings (as far as possible) on BSG are checked as errors are frequent in publications. The following general terms are used to define various altitude zones in the tropics, with all zones being lower at higher latitudes. 

Altitudinal biome zones (in m with equivalents (in tropics) in other literature in brackets) are: 

0-750 lowland (tropical) 

750-1,250 foothill (subtropical, lower montane, cloud forest) 

1,250-1,750 lower montane (temperate, premontane, cloud forest) 

1,750-3,000 montane (upper montane) 

2,800-3,400 elfin forest 

3,400-5,000 paramo or puna grassland (depending on climate and geology) 

5,000+ usually barren 

It seems these terms (just as terms used for habitat descriptions) are as variable as the dimensions of the bills on Darwin’s Finches, but after much consideration the above as given, are I feel workable definitions. On this website the terms tropical, subtropical and temperate etc should only be used to refer to an area’s latitude and not its elevation, as seems to be the confusing and recent use in many publications. BSG therefore follows BirdLife International in this respect. 

The various zones are defined by species composition but there is overlap, and the overlap range varies with local conditions. The further away from the equator generally the lower the ranges drop. The further inland the area, generally the more extreme are the temperature ranges. Dry areas gain and lose heat faster than humid areas. All habitats in the lowest zones that lie between the Tropic of Cancer in the northern hemisphere and the Tropic of Capricorn in the antipodeans should be imagined as being prefixed ‘tropical’. Subtropical habitats lie at higher latitudes than the tropics but still have biotical similar affinities. Subtropical latitude, low altitude areas though having seasonal variations in temperate are almost totally frost free, temperate latitude, low altitude areas on the other hand experience frequent and often severe sub-zero temperatures. 

REFERENCES 

For a list of reference used consult Selected Links on BSG.

www.birdingsiteguide.com