GEOG 235. Biogeography

ZOOGEOGRAPHIC PROVINCES

Zoogeographic provinces are regions of distinctive fauna. They are based on the taxonomic or phylogenetic relationships of animals and not the adaptations of animals to specific environments. One way of looking at this is to think of the fauna of each province as constituting the gene pool available to the forces of natural selection to adapt animal life to the variety of habitats present in the particular region. The gene pool (i.e, the taxa represented) is different in each province.

As for any region in geography, a province maintains a level of homogeniety within its borders and clearly differs from adjacent areas. The boundaries between zoogeographic provinces are drawn according to the distribution of vertebrate taxa (in particular, families). Sclater, who is commonly acknowledged as the developer of this system of drawing regions according to fauna, based his regions on the taxonomic relationships of birds; but the same regional limits work well enough for fishes, amphibians, reptiles, and mammals. The exact locations of boundaries are problematic. For example, the boundary between the Oriental and Australian provinces has been redrawn several times; the most famous rendition is known as Wallace's Line, which falls between Borneo and Sulawesi and between the tiny islands of Bali and Lompoc. The latter pair of islands are separated by a mere 20 miles, but for the most part they are inhabited by different families of mammals and even birds.

Look at the map of zoogeographic provinces. With what physical features of the earth do the borders coincide?

(When the world is subdivided into regions according to the distribution of plant taxa, the resulting regions, known as Floristic Kingdoms, do not coincide with zoogeographic regions. What factors could account for the differences in the distribution patterns of vertebrates and (flowering) plants?)

Synopsis of Zoogeographic Regions as they pertain to mammals

PALEARCTIC ZOOGEOGRAPHIC PROVINCE

• 28 families total; 2 are endemic (the mole rats, and another rodent group, the seleviniids).
• 22 families shared with the Ethiopian
  19 families shared with the Oriental
  Many in common with the Nearctic (to the degree that the same genera and in some cases the very same species are found in both regions)

• 24 families total; 4 are endemic (pronghorn, mountain beaver, pocket gophers, pocket mice)
• Most are widely distributed, especially in the Palearctic
  4 families shared with the Neotropical, but each is represented in Nearctic by only one species (armadillo, opossum, porcupine, peccary)

• 32 families total; 16 are endemic (10 are caviomorph rodents; 3 are in the nearly endemic order Edentata—sloths, anteaters, and armadillos; 1 is a marsupial; and 2 are monkeys)
• 4 families shared with the Nearctic (each represented in the Nearctic by only one sepcies)
  1 shared with the Palearctic (Camelidae), and
  1 shared with the Oriental (Tapiridae)

• 38 families; 12 endemic (including giraffes, hippopotamus; aardvark, elephant shrews, otter shrews, hyraxes, golden moles, and several rodents)
• 22 families shared with the Palearctic
  8 shared with the Oriental ( in many cases the same genera are found in both regions)

• 30 families; 4 endemic families (2 primates—flying lemurs; tree shrews; hairy hedgehogs; spiny dormice)
  • 1 endemic order (spiny dormice)
• 19 families shared with the Palearctic
  8 shared with the Ethiopian (e.g., elephants, rhinoceroses, great apes)
  1 shared with the Neotropical (Tapiridae)

• 9 families; 8 are endemic (6 are marsupials, 2 are monotremes—a subclass of mammals)
• the one non-endemic family is shared with the Palearctic (the only placental mammal, a mouse)