~ 966 ~
Journal of Entomology and Zoology Studies 2018; 6(5): 966-971
E-ISSN: 2320-7078
P-ISSN: 2349-6800
JEZS 2018; 6(5): 966-971
© 2018 JEZS
Received: 16-07-2018
Accepted: 17-08-2018
Tanko D
Department of Biological
Sciences, Federal University
Lokoja, Kogi State Nigeria
Shitta KB
Department of Biological
Sciences, Federal University
Lokoja, Kogi State, Nigeria
Correspondence
Tanko D
Department of Biological
Sciences, Federal University
Lokoja, Kogi State Nigeria
Community structure and composition of
terrestrial macro-invertebrates in relation to bird
and flora abundance at inselberg ’s ecosystem in
Zaria, Nigeria
Tanko D and Shitta KB
Abstract
Species composition and abundance of terrestrial macro-invertebrates associated with Dumbi inselberg
and its surrounding woodland was studied for 24 months. Inselbergs’s ecosystems if not tampered with,
could play important role in biodiversity preservation. The value of diversity of an ecosystem is viewed
in terms of numbers of species interacting among themselves and the abiotic environment. Primary and
secondary instruments were used for data collection. Primary data was done through field visits using
pitfall traps, sweep net and direct search techniques for collection of the invertebrates. The secondary
instrument was data adapted from existing data on vegetation and avifauna of the site. A total of 78
species of invertebrates belonging 43 families were collected. The woodland surrounding the inselberg
had more species diversity (75) compared to the inselberg. Families Formicidae, Pieridae, gryllidae and
pentatonidae had the highest number of species of 5 each. Zonocerus variegatus with 204 individuals had
the highest population. Shannon-Wiener diversity and equitability indices of woodland macro-
invertebrates were higher than those of the inselberg. Highly significant negative correlation was
observed between the macro-invertebrates abundance and the bird’s abundance on the woodland.
However, this relationship was not significant in the inselberg’s plot. The tree density of the woodland
correlated positively with the invertebrates. Similarity index (60%) showed the woodland and the
inselberg’s invertebrates to be similar. The higher density and diversity of invertebrates at the woodland
may be due to high density of vegetation in the woodland than the inselberg. Significant negative
correlation between birds and invertebrates is expected because a greater number of bird species
encountered at the site were insectivorous. It is recommended that a complete inselberg ecosystem should
be set aside for in-situ conservation of their biodiversity.
Keywords: Inselberg, Macro-invertebrates, abundance, woodland, avifauna
Introduction
Inselbergs in an arid environment if not tampered with, could play an important role in
preserving biodiversity and forming refuges for species no longer able to grow in the
surrounding plains
[1, 2]
where some species have become extirpated. The loss of species from
the plains could either be due to human impacts such as overgrazing and subsequent
degradation, or changes in key environmental factors such as climate. Inselbergs could
therefore serve as species pools which, under favourable conditions, allow species to re-
colonise the surrounding plains and thus contribute to the restoration of degraded lands.
The value of diversity of an ecosystem is viewed in terms of numbers of species interacting
among themselves and with the physical environment. Tropical ecosystems are under much
pressure globally. Such pressure on the forest and the woodland is likely to escalate to the
inselbergs which in recent times are considered “forgotten granites habitat”. Terrestrial macro-
invertebrates serves as good ecological indicators
[3]
. The class insecta (the most predominant
invertebrates) are usually considered as the most surrogate representatives of environmental
quality changes, especially Lepidoptera
[4]
. They perform essential ecosystem services in the
pollination of plants
[5]
, recycling of soil nutrients and degradation of organic matter. Macro-
invertebrates also serve as food to birds and other predators such as reptiles and some
mammals (e.g. foxes). Higher density of birds was observed by Tanko et al.
[2]
at locations
with thickets and dense vegetation than areas with sparse vegetation at the study site. They
attributed this to high leaf litter from the vegetation which harbours invertebrates that are food
to the birds.