ANALYSIS
By Emmanuel O. Akindele
As human populations grow, pure freshwater systems are becoming rare around the world. Urbanisation and infrastructure development have had an impact on the natural environment in African countries, as elsewhere. Many species have become extinct.
In Nigeria, various environmental pressures have jeopardised
freshwater biodiversity in recent years. Undisturbed freshwater systems have
become scarce, as human activity has destroyed many rivers, lakes and streams.
Cutting down trees, using water for domestic and industrial
purposes, farming on river banks, dumping garbage and washing are some of the
activities that contribute to reducing freshwater biodiversity.
Studies have found that the animals in Nigeria's freshwater
ecosystems are mostly species that indicate low or moderate water quality. In
the waters studied, there are fewer species that indicate excellent water
quality. Larvae of non-biting midges, soldier flies and hover flies are
examples of species that indicate poor water quality. But biological indicators
of excellent water quality, such as mayflies, stoneflies and caddisflies, are
frequently underrepresented.
My research group recently conducted an ecological study of
the freshwater systems of three waterfalls in Nigeria's remote regions. They
are all far from human settlement and are situated in Nigeria's different
vegetation and geographical zones. Our findings revealed that the streams had
exceptional biological water quality, which is unusual in Nigeria.
It's important to protect these places because pristine
freshwater ecosystems are becoming rarer globally.
Freshwater systems in Nigeria
Three insect orders are frequently employed as indicators of
high-quality freshwater habitats.
Ephemeroptera (commonly known as mayflies), Plecoptera
(stoneflies), and Trichoptera (caddisflies) make up the indicator. In most
cases globally, pristine freshwater systems have no fewer than 10 species of
the three insect groups. The three insect groups are used as the benchmark for
identifying top-quality sites. Such sites should support a wide range of
species of the three insect orders. The higher the indicator value, the richer
a freshwater system is in terms of biological diversity.
At Arinta Waterfalls in Ekiti State, southwest Nigeria, we
discovered 19 species indicating excellent water quality. At Ekor Waterfalls in
Cross River State, southern Nigeria we found 13. We discovered 29 indicator
species at Oowu Waterfalls in Kwara State, north-central Nigeria. These records
exceeded the benchmark for freshwater systems with excellent ecological
integrity. In Nigeria it's rare to exceed this benchmark.
Our findings also revealed that the three sites had very
high conservation value. An index value of not less than 20 is the standard. At
all three locations, the index was greater than 20. The conservation index has
been applied in Britain and Ireland for identifying freshwater systems of
conservation importance. Its application has been recommended for international
use. This study is the first application of the index in tropical Africa.
Freshwater environments with high conservation value have
great promise for both terrestrial and freshwater biological diversity. They
also bode well for human survival. Many insects require clean water to survive
as larvae before maturing into adults and moving to forested areas near water.
They become part of the food chain in these forests, passing their chemical
energy to other animals. The larval insects are also essential food for fishes.
When present in significant numbers, the indicator group is
a clear signal of natural freshwater with preserved riparian forests - little
altered by human activity. Such freshwater systems imply a high level of
naturalness and make an excellent ecotourism destination.
Potential for ecotourism
Apart from their biodiversity value, the three locations we
studied have the potential to become ecotourism destinations in Nigeria. At
present, ecotourists under-appreciate the sites, and ecologists under-report
them. Only the Arinta Waterfalls site is under the close supervision of Ekiti
State Tourism Board. The Abia village community in Cross River State is
responsible for managing the Ekor Waterfalls site. Though the Kwara State
Government recognises the Oowu Waterfalls as an ecotourism site, poor management
and a poor road network leading to the site indicate that it is neglected.
Among the three, Oowu Waterfalls is remarkable for being the
steepest and one of the highest waterfalls in West Africa.
The absence of well-organised management at the locations
foreshadows a serious threat to these exceptional freshwater systems. There are
already symptoms of uncontrolled human activity such as deforestation and
tourist garbage dumping, albeit on a small scale.
Concerned governments should devise ways to protect and
conserve these excellent streams. The goal is to identify freshwater habitats
of high ecological integrity for conservation before they are spoilt by human
activities. Protecting biodiversity will also meet other human needs like
tourism, agriculture and mining.
The authorities need plant and animal ecologists to take an
inventory of the sites' terrestrial and aquatic biodiversity. This baseline
data is critical to draw up conservation plans, monitor naturalness and protect
sites during future infrastructure developments.
Emmanuel O. Akindele, Senior Lecturer, Obafemi Awolowo
University
This article is republished from The Conversation Africa
under a Creative Commons license. Read the original article