EffectGarshong et al.:of EffectHabitat of infrastructural Change development through on small mammal Infrastructural diversity 1 Development on Small Mammal Diversity and Abundance on the Legon Campus of the University of Ghana R. A. Garshong*, D. K. Attuquayefio and F. Gbogbo Department of Animal Biology and Conservation Science, University of Ghana, P. O. Box LG67, Legon-Accra, Ghana *Corresponding author; E-mail: [email protected] Abstract The study investigated the effect of real estate development on small mammal diversity and abundance in order to inform town planners during their decision-making process. Small mammals were used because they are relatively easy to survey and serve as bio-indicators that provide knowledge on the state of health of the habitat in which they inhabit. The University of Ghana Campus, Legon (UGCL) was divided into two sites: built-up area and the botanical garden, which is less developed. The small mammals were live-trapped using Sherman traps in May 2009 for seven nights by means of transect in the two study sites, using a mixture of peanut butter and corn meal as the preferred bait. The 350 trap-nights yielded 68 captures of five species of small mammals. They were (i) Pygmy mouse (Mus musculoides), (ii) Unstriped grass rat (Arvicanthis niloticus), (iii) Tullberg’s soft-furred rat (Praomys tullbergi), (iv) African giant shrew (Crocidura olivieri) and (v) White-bellied hedgehog (Atelerix albiventris). Small mammal diversity and abundance were similar between the two sites. This may be due to the comparatively large size and the presence of green areas in the built-up area. The preference of C. olivieri for human-interfered habitats may be used to monitor further habitat modification through real estate development in UGCL. Introduction Assessments (EIAs) are carried out before The most important and undoubtedly the the implementation of major developmental number one modern-day cause of species projects such as large-scale mining. However, diversity decline are habitat alteration and the periodic monitoring of the impact of these destruction (Linzey, 2001). Habitat alteration projects on the environment after their and destruction have largely been attributed implementation is often not given the to neglect and unsustainable human activities necessary attention. Also in many cases, the such as estate development (Wuver & conduction of EIAs is not focused on real Attuquayefio, 2006), increased mining estate developmental projects, but rather activities (McCullough et al., 2007), those that are deemed more environmentally agriculture (Jeffrey, 1977; Marini et al., 2009, destructive, like large-scale mining. Ribeiro et al., 2009), logging (Wells et al., Ghana has six public universities, all of 2007), urbanization and increasing human which are witnessing increasing student population (Bakarr et al., 2001; Pauchard et populations in recent times. The University al., 2006). of Ghana, the oldest and largest among them, To forestall serious consequences relating has seen an over 100% increase in student to habitat destruction, Environmental Impact population in the past 10 years to a current West African Journal of Applied Ecology, vol. 21(2), 2013: 1–9. 2 West African Journal of Applied Ecology, vol. 21(2), 2013 student population of 29,754 because diversity is small mammals (Class: enrolment over the years has always Mammalia; Orders – (i) Chiroptera – bats, exceeded the output (Fig. 1). These (ii) Rodentia – rodents, (iii) Soricomorpha – increments prompted a corresponding shrews and (iv) Erinaceomorpha – increase in student housing facilities, hedgehogs). Small mammal communities are administrative offices, and lecture theatres relatively easy to survey, and because they to cater for accommodation and office space serve as food sources for many other needs of the growing university community. organisms such as owls, changes in their The increase in infrastructure has resulted in diversity and populations can easily be used the clearance of large tracts of lands at the to deduce trends in other faunal communities. expense of many terrestrial fauna. It is, Most studies on the impact of land-use therefore, important that faunal species on small mammals are, however, carried out abundance and diversity in isolated patches in protected areas (Attuquayefio & Ryan, of vegetation enclosed within real estates be 2006), agroforests (Fitzgibbon, 1997) or compared with relatively undisturbed habitats farmlands (Barnett et al., 2000). Thus, of similar ecological status to help detect the available data interlinking real estate trends in faunal change. development and small mammal communi- One group of organisms that provide ties, necessary in town planning decision- insight to environmental health and faunal making, is largely limited. No. of students Year Fig. 1. Trends in student enrolment and number graduating (output) over a 13-year period Garshong et al.: Effect of infrastructural development on small mammal diversity 3 The University of Ghana Campus, Legon of Accra as “an island in a sea of (UGCL) has a built-up area in which the urbanization” in which Madina and increasing infrastructural development has Kwabenya had been swallowed up. been centred contrary to the nearby The Legon Campus has an area of about botanical garden. Though the University of 13 km2, with a climate characterized by a Ghana is equally surrounded by settlement pronounced gradient of mean annual rainfall in a large spatial scale and can best be ranging from 733 mm to 1,118 mm and an described as an island in the sea of altitude of between 91 m and 122 m (Decher urbanization, the botanical garden has seen & Bahian, 1999). The vegetation is generally minimal infrastructural development and coastal scrub and thicket but with an could serve as important refugia for many anthropic landscape (farm regrowth, football species of animals. The state of health of pitches, built-up areas, etc.). the environment is determined by the kind The built-up area of Legon Campus has of species living in it and the absence of hostels and halls of residence, lecture certain key species that would have theatres, departmental blocks, staff otherwise been expected to exist within the bungalows, lawns and major roads, with low habitat. The paper compares the diversity growing grassland. Avenue trees such as and abundance of the small mammals of Khaya senegalensis, Erythrophleum sp. and Millettia thonningii line the major UGCL to that of the adjoining botanical roads. On the contrary, the university garden in order to determine the effect of botanical garden, with little infrastructural infrastructural development on the diversity development, covers an area of about 0.25 and abundance of small mammals. km2 and supports scientific research. It also has facilities for picnics. The vegetation Materials and methods consists of a mosaic of forest type vegetation, Study area patch of the original thicket vegetation, The Legon Campus of University of Ghana woodland (mainly neem trees, Azadirachta 0 0 (5 36’ N, 0 10’ W) is located in Accra, indica) and grassland composed mainly of which has an estimated population of Heteropogon contortus, Sporobolus 3,963,264 in 2011. Originating from rural- pyramidalis, elephant grass (Pennistum urban drift, increasing developmental purpureum) and ‘Acheampong’ weed activities and rapid expansion of the city of (Chromolaena odorata). Accra has resulted in the destruction of many faunal habitats within the Accra Site selection Plains. According to Grimes (2006), the The vegetation type in the built-up area suburbs of Accra began to spread was basically similar, comprising of grassland northwards in the 1970s and the northern with few interspersed trees at certain ward limit was about 5 km south of Legon. locations, hence, the study sites in the built- Also, about 1 km north and northeast of up area were randomly selected. The Legon in the 1970s was the village of Madina botanical garden, however, had four distinct and Kwabenya. Grimes (2006), however, vegetation types: thicket, forest, grassland and described Legon in the face of the expansion woodland. Transect lines were, therefore, 4 West African Journal of Applied Ecology, vol. 21(2), 2013 established to cut across the different throughout the study period. Trap stations vegetation types taking their relative sizes into were relocated each day. consideration (Fig. 2). The captured small mammals were sedated using chloroform then identified, Live-trapping of small mammals sexed (using the ano-genital distance, which Small mammals were captured using is longer in males), weighed and examined Sherman collapsible traps (23 cm × 9 cm × for reproductive condition (abdominal or 7.5 cm) for seven consecutive days in May scrotal testes in males and enlarged nipples, 2009. Twenty-five traps were separately perforate vaginas and pregnancy in females). used for the study in the built-up area and Lactating females had bare areas around the botanical garden, giving a total of 175 trap- nights per area. The traps were baited with a mammae, indicating suckling from the young. mixture of peanut butter and corn meal and Pregnancy was determined by weight and placed at 10-m intervals along transect lines. feeling of foetus with fingers. Reproductive Traps were set, rebaited and replaced at males exhibited prominent scrotal testes. sunset around 16:00 h GMT and inspected Field handling techniques followed Davies around 06:00 h GMT the next morning & Howell (2004). Fig. 2. Distribution of