Fisheries in the Southern Border Zone of Takamanda - Impact ...
Fisheries in the Southern Border Zone of Takamanda - Impact ...
Fisheries in the Southern Border Zone of Takamanda - Impact ...
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Odonate assessment<br />
species extant <strong>in</strong> <strong>the</strong> subfamily - two species <strong>in</strong> <strong>the</strong><br />
Cameroon and Nigeria border region and one species <strong>in</strong><br />
<strong>the</strong> Guyana Highlands). The larvae are adapted to cl<strong>in</strong>g<br />
to <strong>the</strong> undersides <strong>of</strong> boulders <strong>in</strong> cold torrential streams.<br />
The species P. stahli occurs both north (<strong>in</strong>clud<strong>in</strong>g<br />
<strong>Takamanda</strong>) and south <strong>of</strong> <strong>the</strong> Cross River, and it is<br />
essentially <strong>the</strong> <strong>in</strong>dicator species <strong>of</strong> submontane streams<br />
flow<strong>in</strong>g through undisturbed forest. There is ano<strong>the</strong>r<br />
species, P. gamblesi, which is only known from Obudu,<br />
Nigeria (only one specimen has ever been found) and this<br />
could be expected <strong>in</strong> higher altitude forests <strong>in</strong><br />
<strong>Takamanda</strong>. Its larva awaits discovery and its<br />
relationships will be fasc<strong>in</strong>at<strong>in</strong>g to discern.<br />
Nubiolestes diotima is <strong>the</strong> only African species <strong>of</strong> a<br />
small family, <strong>the</strong> Perilestidae, which is o<strong>the</strong>rwise<br />
neotropical. The discovery <strong>of</strong> its larva at Kupe and <strong>the</strong><br />
observation <strong>of</strong> synapomorphisms has added strength to<br />
its placement <strong>in</strong> <strong>the</strong> family (Vick 1998). It has been found<br />
at <strong>Takamanda</strong>. It occurs <strong>in</strong> backwaters <strong>of</strong> submontane<br />
streams which flow through dense forest.<br />
Genera with aff<strong>in</strong>ities with <strong>the</strong> Madagascar fauna are<br />
<strong>in</strong> <strong>the</strong> Megapodagrionidae: Nesolestes and Neurolestes.<br />
Neurolestes is represented by one species, tr<strong>in</strong>ervis,<br />
which appears to be relatively common <strong>in</strong> <strong>Takamanda</strong><br />
(and less so to <strong>the</strong> south); Nesolestes is known from<br />
across <strong>the</strong> border <strong>in</strong> Obudu, Nigeria, and at Mount Oku<br />
<strong>in</strong> Northwest Prov<strong>in</strong>ce, and could be expected <strong>in</strong><br />
<strong>Takamanda</strong>, perhaps occurr<strong>in</strong>g with Pentaphlebia<br />
gamblesi at higher elevations than Pentaphlebia stahli<br />
and Neurolestes tr<strong>in</strong>ervis.<br />
O<strong>the</strong>r biogeographical puzzles occur <strong>in</strong> <strong>the</strong> area such<br />
as Stenocnemis a platycnemidid not closely related to any<br />
o<strong>the</strong>r taxon (Vick 1998) and Tragogomphus (three<br />
species endemic to Cameroon and Nigeria).<br />
4.4 African demoiselles: <strong>the</strong> Calopterygidae<br />
The Southwest Prov<strong>in</strong>ce is a hotspot for calopterygid<br />
diversity. Three genera are present, and <strong>in</strong> <strong>the</strong> Prov<strong>in</strong>ce<br />
alone <strong>the</strong>re are 12 species (<strong>in</strong>clud<strong>in</strong>g two ‘forms’ which<br />
appear to be specifically dist<strong>in</strong>ct) present <strong>in</strong> <strong>the</strong> genera<br />
Umma, Phaon, and Sapho. In contrast, sampl<strong>in</strong>g to date<br />
<strong>in</strong> Ghana has revealed four species, while Uganda and<br />
Kenya share two; even Congo (DRC) only has five<br />
(O’Neill and Paulson 2001, Clausnitzer 2001). Most taxa<br />
are ra<strong>in</strong>forest-stream specialists. There appears to be a<br />
difference between <strong>the</strong> fauna <strong>of</strong> <strong>Takamanda</strong>, north <strong>of</strong> <strong>the</strong><br />
Cross River, and that <strong>of</strong> <strong>the</strong> area to <strong>the</strong> south. Widespread<br />
taxa (i.e. occurr<strong>in</strong>g north and south <strong>of</strong> <strong>the</strong> Cross River)<br />
are Umma mesostigma (see below) and Sapho<br />
orichalcea (mostly <strong>in</strong> submontane ra<strong>in</strong>forest). Phaon<br />
iridipennis is a common African taxon which occurs <strong>in</strong><br />
disturbed habitat <strong>in</strong> <strong>the</strong> region. A much more localised<br />
taxon, Phaon camerunense occurs from Gu<strong>in</strong>ea to<br />
Cameroon and it appears to be conf<strong>in</strong>ed to lowland<br />
ra<strong>in</strong>forest. Both species <strong>of</strong> Phaon have been found <strong>in</strong><br />
<strong>Takamanda</strong> and <strong>the</strong> areas to <strong>the</strong> south.<br />
In <strong>the</strong> genus Sapho, we have two taxa present to <strong>the</strong><br />
south (possibly a third pend<strong>in</strong>g verification), but to date<br />
<strong>in</strong> <strong>the</strong> <strong>Takamanda</strong> region we have only found <strong>the</strong><br />
predom<strong>in</strong>antly submontane, or cool-stream lowland<br />
species, Sapho orichalcea.<br />
In <strong>the</strong> genus Umma we have recorded eight taxa for<br />
<strong>the</strong> SW Prov<strong>in</strong>ce. Umma mesostigma is <strong>the</strong> most<br />
widespread species,occurr<strong>in</strong>g <strong>in</strong> <strong>Takamanda</strong>, and south<br />
<strong>of</strong> <strong>the</strong> Cross River, <strong>in</strong> both submontane and lowland<br />
habitats, usually <strong>in</strong> forests, but not necessarily<br />
undisturbed. Ano<strong>the</strong>r species Umma longistigma occurs<br />
<strong>in</strong> two forms which may be separate species: one form<br />
occurs to <strong>the</strong> south <strong>of</strong> <strong>the</strong> Cross River from <strong>the</strong> Bakossi<br />
mounta<strong>in</strong>s southwards, while ano<strong>the</strong>r form with<br />
narrower <strong>in</strong>ferior appendages occurs <strong>in</strong> <strong>Takamanda</strong>,<br />
Korup, and <strong>in</strong> adjacent parts <strong>of</strong> Nigeria. An endemic<br />
species Umma mesumbei occurs <strong>in</strong> submontane streams<br />
at Kupe and <strong>the</strong> Bakossi Mountians (Vick 1996). This<br />
species has not been recorded with<strong>in</strong> <strong>Takamanda</strong>.<br />
However, current surveys have rediscovered Umma<br />
purpurea, described from Mamfe <strong>in</strong> 1961. The species<br />
appears to be absent to <strong>the</strong> south, but curiously it is<br />
locally common on Bioko (Brooks and Jackson 2001).<br />
Umma puella is ano<strong>the</strong>r taxon which has only rarely been<br />
encountered s<strong>in</strong>ce its discovery <strong>in</strong> 1917. The species was<br />
found near Mount Cameroon <strong>in</strong> 1979 and at several sites<br />
<strong>in</strong> <strong>Takamanda</strong> <strong>in</strong> <strong>the</strong> current study. This is an <strong>in</strong>terest<strong>in</strong>g<br />
77<br />
SI/MAB Series #8, 2003