ISBN: 2141 – 1778 jfewr ©2016 - jfewr Publications E-mail:[email protected] 80 FRUGIVOROUS BIRD SPECIES DIVERSITY IN RELATION TO THE DIVERSITY OF FRUIT TREE SPECIES IN RESERVED AND DESIGNATED GREEN AREAS IN THE FEDERAL CAPITAL TERRITORY, NIGERIA 1Ihuma, J.O; Tella, I. O2; Madakan, S. P.3 and Akpan, M2 1Department of Biological Sciences, Bingham University, P.M.B. 005, Karu, Nasarawa State, Nigeria Email:[email protected] 2Federal University of Technology, Yola, Nigeria, Department of Forestry and Wildlife Management. 3University of Maiduguri, Borno, Nigeria, Department of Biological Sciences ABSTRACT The diversity of frugivorous bird species in relation to tree species diversity was investigated in Designated and Reserved Green Areas of Abuja, Nigeria. The study estimated, investigated and examined trees species and avian frugivore in terms of their diversity. Point-Centered Quarter Method (PCQM) was used for vegetation analysis while random walk and focal observation was used for bird frugivore identification and enumeration. data was collected from six locations coinciding with the local administrative areas within the Federal Capital Territory. These were, the Abuja Municipal Area Council (AMAC), Abaji, Bwari, Gwagwalada, Kuje and Kwali. AMAC is designated as urban while the remaining five sites are designated as sub-urban. The highest number of fruit tree species was encountered in AMAC (30), followed by Abaji (29) while 27, 25, 19 and 11 fruit tree species were encountered in Kwali, Bwari Gwagwalada and Kuje respectively. The similarity or otherwise dissimilarity in fruit tree species composition between each pair of the enumerated sites showed Gwagwalada and Kuje as the most similar, and the similarity or otherwise dissimilarity in frugivorous bird species composition between each pair of the enumerated showed higher species similarity between the AMAC and each of the other sites, and between each pair of the sites than that of the fruit trees in the respective sites. Highest number of frugivore bird species was encountered in Kwali (41), followed by Bwari (39) and AMAC (38) while 35, 34 and 21 species were encountered in Gwagwalada, Kuje and Abaji respectively. The alpha (within-site) diversity of frugivore bird species at different sites using Simpson and Shannon-Wiener diversity indices showed that Gwagwalada is the most diverse of all the sites, followed by Kuje and Kwali respectively. The diversity indices of frugivores and fruit-trees were correlated, a weak relationship was observed (r= - 0.2323 and r = - 0.1626), and Null hypothesis was accepted. Also, ANOVA was carried out to test for significance between the sites and the tree physical structure parameters. The result showed no significant difference between the sites (Fcal=0.236603 and F Crit =2.901295), and the null hypotheses was accepted. Again, there was significant differences between the tree physical structure parameters (Fcal=20.58803 and F Crit =3.287382), the null hypothesis was rejected. It was therefore concluded that these reserved areas need more protection to enhance both the beta and alpha diversities in order to support more interactions. Keywords: Frugivores, Fruit trees, Diversity, Interaction, Green Areas, Urban ecosystems. INTRODUCTION ecosystem functioning. Ecosystems with Biodiversity is significant for a wide range of greater diversity are regarded as more complex reasons including the intrinsic value that it has and are expected to be more stable i.e. more to humanity. For ecologist, the primary concern resistant or resilient to disturbance. Thus, with biodiversity is in its relationship with higher biodiversity is expected to bestow JOURNAL OF RESEARCH IN FORESTRY, WILDLIFE AND ENVIRONMENT VOLUME 8, No 1 MARCH, 2016 FRUGIVOROUS BIRD SPECIES DIVERSITY IN RELATION TO THE DIVERSITY OF FRUIT TREE SPECIES IN RESERVED AND DESIGNATED GREEN AREAS IN THE FEDERAL CAPITAL TERRITORY, NIGERIA 81 greater stability to an ecosystem (Rooney et al., structure and composition) tend to support most 2006). The complexity-stability hypothesis was bird species, because diverse habitat structure first put forward by MacArthur (1955) and offer a variety of ecological niches occupied by Elton (1958). Although some studies (e.g. May, different bird species at different time. 1972) have cast doubt on this hypothesis, many Frugivorous bird species play a significant role others appear to support it (e.g. McCann 2000; in seed dispersal thus creating plant-frugivore Ives and Carpenter, 2007). interactions that constitute an important step in Biodiversity is viewed from several the reproductive cycles of many plants (Harper, perspectives including genetic diversity, species 1977) and the sustenance of natural forest diversity, functional diversity and habitat regeneration within the urban environment. diversity. Each of these types provides some Changes in bird species composition and form of heterogeneity to the system and, in this abundance have been associated with changes way, affects both the structure and function of in habitat heterogeneity ( Shankar Raman, ecosystems. One way in which biodiversity can 2001). influence ecosystem function is through the As in the natural environment, increase in spatial heterogeneity (Chesson and biodiversity is also important in urban Rosenzweig, 1991). Spatial heterogeneity is ecosystems. Urban ecosystems have been bestowed on the ecosystem system through the described as nodes of interaction between diversity of habitats it contains as well as its humans and nature (Pickett et al., 2001), and species composition. For example, a higher tree have dynamics similar to those of natural species composition can affect diversity of ecosystems. They are, however, faced with other species since trees can serve not only as a challenges that are peculiar to them. These source of resources such as food and shelter but include altered drainage as a result of increased also influence abiotic conditions and create impervious surfaces and other anthropogenic microhabitats. Bird species diversity, in perturbations. Consequently, ecological factors particular, is expected to be influenced by tree that enhance resilience and stability are species diversity since birds rely a great deal on particularly important in urban ecosystems. trees as resources in one way or the other (e.g. Since enhanced diversity is associated with nesting, roosting and feeding). According to higher ecosystem stability, this has become an Wiens and Rotenberry (1981), areas of higher important area of interest for urban ecologists habitat diversity (more complex in physical and conservation biologists. JOURNAL OF RESEARCH IN FORESTRY, WILDLIFE AND ENVIRONMENT VOLUME 8, No 1 MARCH, 2016 Ihuma et al 82 The Federal Capital Territory of Nigeria the North of the territory. This enormous area is a planned area in central Nigeria designed to was considered essential in order to allow room be the administrative capital of Nigeria. It not just for the capital city but also for a city includes a number of Designated Green Areas region that will provide most of the needs of the (DGAs), some of which are regarded as city, including parks, gardens, reserved green Reserved Green Areas (RGAs). DGAs are areas, water, forestry, industrial, agricultural, portions of land within the FCT where defense, air transport and other needs infrastructural developments are prohibited, but (Danmole, 2004). accessed by people and hold intact the Data Collection representative samples of the actual fauna and The study area was divided into two strata flora before the urbanization. RGAs designated representing urban and sub-urban locations. areas with total restrictions to both human The urban stratum comprised of the AMAC activities and infrastructural development. area while Abaji, Bwari, Gwagwalada, Kuje Designated areas are crucial for the and Kwali were regarded as sub-urban. AMAC, maintenance of biodiversity within FCT. It is the urban stratum, is highest density therefore important to collect ecological commercial, residential and government offices information necessary for their management. area of the FCT while the suburban areas are This study is intended to provide some satellite settlements surrounding AMAC and information on the relationship between tree separated from it by an expanse of sparsely species diversity and bird species diversity inhabited mosaic of natural vegetation and within the FCT as part of that process. farmland. The suburban sites are separated MATERIALS AND METHOD from each other by at least a distance of less Description of the Study Area than 3k and are linked to one another by natural This study was conducted within the Federal corridors. Within the AMAC are natural and Capital Territory (FCT), Abuja, Nigeria. artificial corridors linking metapopulations. According to NAPEP (2003), Abuja is on a Identification and Enumeration of Fruit 8,000 square-kilometer land area. The FCT is Trees located between latitude 80 251 and 90 251 north Vegetation sampling was conducted by of the equator and longitude 60 451 and 70 451 P.C.Q.M (Kevin, 2007; Machange, 1985). east of Greenwich Meridian and is bounded by P.C.Q.M was carried out by measurement of Niger to the West, and North West, Nasarawa distances from randomly chosen points to the to the East, Kogi to the South and Kaduna to JOURNAL OF RESEARCH IN FORESTRY, WILDLIFE AND ENVIRONMENT VOLUME 8, No 1 MARCH, 2016 FRUGIVOROUS BIRD SPECIES DIVERSITY IN RELATION TO THE DIVERSITY OF FRUIT TREE SPECIES IN RESERVED AND DESIGNATED