DOI: 10.5061/dryad.zcrjdfnd5
title: Bird habitat preferences are related to habitat type and disturbance in the Owabi Wildlife Sanctuary, Ashanti Region (Ghana)

description: Context: Globally, an estimated 1.3% of the bird population has
 gone extinct over the last millennia largely due to loss of habitat
 preferences. Aims: This short-term study investigated
 disturbance-related drivers as predictors of bird habitat selection and
 assemblages in the Owabi Ramsar wetland. Methods: The study was
 carried out over a five-month period (May to September 2019), in four
 habitat types (farmlands, Built-up, forest reserve, and open water area).
 Data was collected in 84 plots across four habitats, using a point-count
 cantered technique. The Gambin model, nMDS, Chao-1, and Hill numbers
 models were used to evaluate bird distribution, habitat preferences, and
 diversity, while the CCA ordination technique was performed to examine the
 influence of drivers on bird assemblages. Key results: In all
 1,260 individual birds, belonging to 81 species were identified. The
 Majority of the birds preferred the farmlands and built-up habitats in
 spite of the severe disturbance (e.g., crop farming, sand winning, and
 fire), accounting for 55.39% variability in their community structure. The
 open water was the least preferred habitat and was dominated by the
 White-faced whistling duck. Despite the drop in species similarity with
 increasing disturbance from the open water to the built-up, fewer than
 five species were widely distributed in all the four habitats (e.g.,
 Bronze-mannikins and White-throated bee eater), indicating their broad
 range habitat preferences and ability to adapt to varied conditions. The
 forest reserve tended to be the most diverse, reflecting the spatial
 distribution of birds mediated by nesting microhabitats, varied food
 availability, less predation, and low disturbance.
 Conclusions: The study adds to previous work on the impact of
 increasing disturbance on the Owabi Ramsar wetland ecosystem. This study
 particularly highlights the role of disturbance-related drivers and
 habitat type in bird habitat preference and the need to intensify
 conservation activities within the catchment of the Owabi Wildlife
 Sanctuary. Implications: Giving the increasing level of
 disturbance, there is the likelihood that the forest and water-dependent
 bird population will decline sooner if managers of the wildlife sanctuary
 fail to halt dumped solid waste in the open water, logging and expansion
 of croplands into the forest reserve.
description: Study area and
 sites Owabi Wildlife
 Sanctuary was established in 1971 and is located approximately 23 km
 northwest of Kumasi in the Ashanti Region of Ghana (Oduro and Aduse-Poku
 2005). The study area is located in the Owabi Wildlife Sanctuary
 (6<sup>0</sup> 47’ 3.32”- 6<sup>0</sup> 41’ 52.31”
 N and 1<sup>0</sup> 44’ 0.81”- 1<sup>0</sup> 37’
 53.04” W) in the Atwima, Kwabre District, Ashanti Region – Ghana
 (Figure1). It is one of the smallest (13 km square where the study will be
 conducted) conservation areas in the Upper Guinea Rainforest of Ghana. It
 is also the only inland Ramsar site protected under the Ramsar Convention
 (Oduro and Aduse-Poku 2005). It was designated a Ramsar site in 1988 and
 managed by the Forestry Commission of Ghana (Garshong <i>et
 al.</i> 2013). The wetland, which is approx. 22 ft deep and covering
 an area of 2.03 ha, with seven streams draining into it (Nartey
 <i>et al.</i> 2019) is surrounded by a forest and a Wildlife
 Sanctuary. The wetland is one of the major supplies of potable water to
 the Kumasi Metropolitan Area (Nunoo <i>et al.</i> 2012). The
 Wildlife Sanctuary is rich with indigenous water birds and various species
 of wintering and staging birds during migration and supports about 199
 vascular plants species (Garshong <i>et al.</i> 2013). The
 climate is semi- humid, with an average annual rainfall of 1,488 mm.
 Rainfall pattern if bimodal, with the main wet season between March and
 June and a minor wet season in September – October. The average annual
 temperature ranges between 24–34°C. Soil type is typical forest ochrosol.
 The surroundings of Owabi wetland and the wildlife sanctuary are subjected
 to a variety of human uses, including crop farming, sand winning,
 livestock grazing, logging, and fishing. Site/plot selection and bird
 sampling procedure across the four
 habitats Four habitats (Farmlands, Built-up, Forest reserve and Open water area) were selected on a current remote sensing image (e.g., TM Landsat 4 image using the stratified random approach. A field reconnaissance survey was then carried out to validate the locations selected for the bird survey. This was followed by another stratified random selection of the survey plots by overlaying 100 grid cells of 25 x 25 m on the TM Landsat 4 image, to cover all the four selected LULC habitats. We employed the fixed radius point count technique of 25 x 25 m dimensions (250 m<sup>2</sup>) (Hutto <i>et al.</i> 1986; Bibby <i>et al.</i> 1992; Sunderland 2006) and at least 150 m apart, to count birds in each of the four sites (i.e., built-up area = 25, forest reserve = 25, agricultural land = 25 and open water area = 9 P.C.C plots); bringing the total to 84 survey plots. Bird count was carried out twice a day; in the early morning hours (6:30 - 9:30 G.M.T.) when they are out feeding and late afternoons (16:30 - 18:30 G.M.T.) when they were most active at low ambient temperature. We slowly walked through each survey plot to visually identify birds at close range or used a pair of Bushnell Falcon binoculars (of 10 x 50 mm dimensions) for birds at distant locations up to 20 m from the centre of the survey plot. In using the pair of binoculars, we looked out for morphological features such as like colour and structure of the beak, colour of a tail feather, colour of feathers around the neck, colour of the head feathers and the presence of comb-like feathers. Birds that were not visually spotted, were identified by their vocalization, with the aid of a highly trained person (<i>Mr. Ossom - Ornithologist</i>) for recognizing of bird species. We avoid counting fly over birds because we assumed that their habitat preference did not strongly relate to the land use types found within the study area. During windy days, bird count was avoided, as sighting birds might be difficult. Bird nest was not counted, since it was practically impossible to establish the species and number of birds co-habitating a nest. Bird count was done on a weekly basis (12 weeks in total), between August and November 2019. All birds were identified <i>in situ</i> with the aid of Birds of Ghana keys (Borrow and Demey 2010; Birds of Ghana Galleries, 2010, http://www.pbase.com/) Assessment of disturbance-related drivers Eight disturbance-related drivers such as erosion, farming, fire, logging, grazing, bare ground, sand winning, and solid waste were first identified on a ground truth assessment and subsequently categorized by adopting Salafsky <i>et al</i>. (2003) and Battisti <i>et al</i>. (2009). This assessment was done to evaluate their effect on bird assemblages across the four habitats. These disturbance-related drivers were assessed weekly for their magnitude (i.e., scope + severity), and in the same plots where birds were sampled. The scope and severity of identified drivers were scored from 1 - 4, with 1 representing low scope and magnitude and 4 represent high scope and magnitude. The scope was assessed according to the percentage of the study plot affected by a given driver within the preceding five years (2014 -2019) (Battisti <i>et al</i>. 2009). To verify whether the identified activities had indeed persisted for at least the preceding five years, one-on-one field interviews were held with managers and users of the wetland (35 persons in all). The scores for scope were assigned as follows: 4: found throughout (50%) the sample plots at the sites; 3: in 15–50% of the plots; 2: found in 5–15% of the plots and 1: found in &lt; 5% of the plots (after Battisti <i>et al</i>. 2009). For ‘‘severity’’ we referred to the degree or intensity to which a driver has physically damaged each plot per site in all four sites. A score of 4 was assigned if the driver led to a severe loss of ground cover and eroded surface; 3 = if the impact induced severe damage; 2 = if the impact led to moderate damage; 1 = if impact induced little or no damage. The magnitude was computed as the sum of the average scope and severity of an activity per plot and ranked (Salafsky <i>et al.</i> 2003).