Masolele MM. the Impact of Forest Invasion in the Glades on Birds in Arusha Copyright© Masolele MM
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Journal of Ecology & Natural Resources ISSN: 2578-4994 The Impact of Forest Invasion in the Glades on Birds in Arusha National Park 1 2 3 Masolele MM *, Kahana LW and Sylvina TJ Research Article 1Serengeti Biodiversity Programme, Tanzania Volume 1 Issue 2 2College of African Wildlife Management Mweka, Tanzania Received Date: August 01, 2017 Published Date: August 21, 2017 3Independent, College of African Wildlife Management Mweka, Tanzania DOI: 10.23880/jenr-16000108 *Corresponding author: Majaliwa M Masolele, Bachelor Degree in Wildlife Management-College of African Wildlife Management, P.O.BOX 661, Arusha, Tanzania, Tel: +255743227297/+255683211137; E-mail: [email protected] Abstract This study was aimed at determining how growth of forest into man-made and natural glades affects bird species diversity, richness and evenness, and feeding guild composition in Arusha National Park, Tanzania. The fixed belt transect plot was used to survey bird species during the wet season. Fifty-eight bird species among 29 Families from 11 Orders were recorded. Passeriformes was the dominant Order for both glade types. The Shannon-Wiener Diversity Index was highest for man-made glades, as compared to that of natural glades (H’=3.677 and H’= 3.1, respectively). Student’s t-test analysis of the means of bird diversity in forest transects and corresponding forest-invaded glade transects showed that there was no significant difference in bird species diversity between the two glade types (t = -3.4208, p = 0.07186). Man- made glades had a higher species richness than natural glades (Margalef’s Richness Index R1=8.93 and R1=6.219, respectively) and this variation was statistically significant (Chi-square: χ2 = 4.5696, P = 0.033). Also, species evenness was higher in man-made glades than in natural glades (Pielou J=0.8069 and J=0.7627, respectively). The Sorensen Similarity Index analysis showed that bird species communities were similar (CC= 0.53), with insectivores being most dominant feeding guild for both glade types. Since the variety of bird species for forest-invaded man-made glades was richer and more even than for the natural glades, we conclude that re-clearing of forest invasion for man-made glades should proceed in order to generate these different unique microhabitats that are vital to the conservation of a wide variety of bird species. This is in contrast to not re-clearing forest invasion into man-made glades, where diverse microhabitats would not be generated or available to support increased bird species richness and evenness. Hence, maintenance of these unique microhabitats will promote less decline of bird diversity in Arusha National Park. The Impact of Forest Invasion in the Glades on Birds in Arusha National Park J Ecol & Nat Resour 2 Journal of Ecology & Natural Resources Introduction influential cause. Tropical forests are chiefly endowed with a diversity of plant and insect species; and hence, Background influences high avian diversity in the equatorial regions [10,2]. Other major factors that influence avian diversity Global patterns of biodiversity change over both space includes competition, predation, mutualism, disturbance, and time and thus, require integrated ecological and natural enemies, physical barriers, climatic events and evolutionary perspectives at temporal and broad spatial most recently, expanding and pervasive human impacts scales to determine how observational changes for given [10]. time-space coordinates [1,2,3,4]. There is an unequal distribution of biodiversity on the earth’s surface, and Habitat loss and transformations, and climate change understanding the factors that control geographical being enormous problems for birds [12,13]. Certain variations is one of the challenges of ecology [5]. sensitive bird species are negatively affected by the Ecological processes, including temporal and spatial eradication of indigenous vegetation, forests, shrub land, differences in the characteristics of a given ecosystem or grassland to make way for agriculture, commercial may contribute to the spatial distribution of species [5]. exotic plantations, or development activities, such as Currently, there is a huge interest in conserving biological human settlement and industrial uses [12]. Draining of diversity due to the sharp increase of species extinction, wetland areas has caused great loss of water birds such as as the result of habitat loss, fragmentation, degradation cranes, geese and ducks. Pollution of air, water, and land and transformation and climate change [6,7]. A diversity inevitably affects bird life [14]. Human disturbance at of bird species inhabits a huge variety of habitats on nesting sites is not tolerated by most species and this different land masses and in fresh and salt water bodies often leads to birds deserting their nests with subsequent around the world, including areas at extreme latitudes loss of eggs or chicks [12]. and land elevations. Some of the smallest nations have many bird fauna [8]. Inadequate community conservation education has led to haphazard farmering practices that has resulted in Birds are important components of the world’s eradication of birds of prey, cranes, and bustards due to ecosystems and one of the most conspicuous groups of pesticide and herbicide poisoning of carcasses and grains, diverse fauna. Although their distribution ranges from and bird shooting and trapping [12]. Habitat oceans to frozen polar zones, steaming rain forest, barren modifications have the potential to cause changes in the deserts, land, freshwater bodies, and from the lowest structure and composition of bird communities [11,13]. deserts to the highest mountains, birds are certainly more Insects form the most important part of the diet of many abundant in some places than others [9,10]. bird species. Also, feeding on snails, beetles or moth Understanding the factors responsible for the uneven larvae that contain insecticide will adversely affect birds distribution of bird species richness is a major challenge to a greater or lesser degree. Depending on the dose and in ecology [11]. Patterns of bird species diversity are how many affected meals are eaten, insecticides can have determined by fundamental biogeographic factors, with a severely debilitating effect on the birds, and even cause tropical countries supporting the highest number of death [12]. species (species richness) especially in South America and Africa. A total of over 10,000 different species of birds Forest is defined as the large area of land or ecosystem worldwide is recognized by Birdlife International, with covered chiefly with large trees and undergrowth [15]. the highest numbers occupying mainland regions, and the Within forested regions are glades, which are “open, rest on the islands [10]. The information about the rocky, barren areas with shallow soils that support distributions of birds are well-known compared to the unique communities of drought-adapted forbs, warm- other taxa, and they are also determined by these season grasses, and a specialized fauna” [16]. Glades can fundamental biogeographical factors. This makes birds a either be natural or man-made. Natural glades that occur useful starting point of mapping broad-scale patterns of in some areas are due to local climatic conditions, species diversity, richness, evenness and endemism [8,10] drainage, and volcanic eruption [16]. Man-made glades There is much to argue about as to which factors have occur due to human activities, such as clearing of forest been vital in driving global patterns of biological diversity. for the purposes of attracting grazers [17]. In most cases, The variations of conditions experienced in evolutionary glades have a slanted terrain because they usually occur time have resulted in the existence of big geographic in the middle of sloped areas with forest cover both above differences in bird species diversity [8]. Variety (and and below. Infrequently, a glade will cover the top of a area) of the diverse habitats present is the most ridge where the terrain is virtually level [18]. Masolele MM. The Impact of Forest Invasion in the Glades on Birds in Arusha Copyright© Masolele MM. National Park. J Ecol & Nat Resources 2017, 1(2): 000108. 3 Journal of Ecology & Natural Resources Many parts of the world, including Africa, are facing the the study aimed to provide management problem of woody plant intrusion [19]. Woody plant recommendations about the conservation and invasion has resulted in the increase of cover of shrubs maintenance of man-made and natural glades based on and trees in some areas, such as glades, plains, savannas the study findings. and grasslands [20]. Forest invasion in a glade is referred to as woody plant encroachment into a grassland island Objectives found in a forest [15]. Woody plants invade the grassland through a process known as bush encroachment. The Overall Objective continuous growth of woody plants is considered a challenge in glades because woody plants alter glade To determine how growth of forest into man-made and structure [18]. Several studies have suggested factors that natural glades affects bird species diversity, richness and contribute to the increase of woody plant encroachment, evenness, and feeding guild composition. including grazing intensity by wild herbivores, frequent fire, precipitation, climate change, increase in Specific Objectives atmospheric carbon dioxide concentration and soil There were two specific objectives: resources [20,16,21]. Forest invasion into the glades affects