Avian Diversity and its Associated Threats in Gharo Creek, District Thatta, Sindh, Pakistan

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INTRODUCTION
B irds are vertebrate animals having feathers on their body, bipedal, endothermic, and oviparous that inhabit water bodies, agricultural fields, urbanized areas, rural areas, and mountainous territories on various altitudes (Govender, 2021;Umar et al., 2018). Birds belong to class aves with various sizes and morphology, that are distributed worldwide but some bird species are endemic to particular regions of the world and habitats (Roberts, 1991). They range in body size from 2 (inches) that is hummingbird (Mellisuga helenae) to the 118 (inches) ostrich (Struthio camelus). Aves is the major group or class of birds which comprises the subdivision Palaeognathae (group of flightless birds), the tiramisu (birds with weak flight), and the Neognathae (flight birds) (Platt et al., 2021). They are pollution-sensitive indicators. Birds devour large numbers of harmful insects, as well as their larvae and eggs, hence serve as biological control agents keeping insect pests populations in check thus being good friends of farmers (Steven et al., 2021). They are social, they communicate using visual signals and through calls and songs and participate in social behaviors including cooperative breeding, hunting, floating, and mobbing of predators. Many species are of economic importance, mostly a source of food acquired through hunting or farming. Some species particularly songbirds and parrots are popular as pets (Roberts, 1991). As bird's richness and diversity are O n l i n e

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the most prevalent lives, which lead beauty to the existing life on the earth. Apart from this, their essentially beautiful plumage, melodious songs, always have fascinated mankind (Roberts, 1991). It is not too fanciful a metaphor to consider Pakistan as lying at the crosswords of Asia's major Palearctic bird migration routes. Apart from resident birds, there are an influx of winter visitors from northern breeding grounds, or summer breeding visitors both from the northern mountainous regions and from the Indus plains to warmer southern latitudes. The explanation for the phenomenon appears to lie more in Pakistan's strategic geographic location rather than in the natural endowment of transport facilities (Roberts, 1991). Similarly, the north of the country is bounded by a continuous palisade of some of the highest mountain ranges in the world, stretching from the Pamirs and Hindukush in Afghanistan, eastward to the Himalayas which continue across the northern frontier of India (Roberts, 1991). The heterogeneous uniqueness of the natural environment is one of the important factors that have increased avian diversity (D'Amen et al., 2017). The current study was aimed to know the avifauna and associated threats.

Study areas
The current study was conducted in Gharo Creek, district Thatta, Sindh during the study period April 2020 to March 2021. It is situated about 65 km from Karachi Pakistan (Fig. 1). Based on scientific purpose the study area was divided into three main habitat types.

Survey design
During the whole study period data were collected in the morning (7:00 am-11:00 am) throughout favorable environmental conditions by using two authentic and recognized methods i.e. (1) Line transect method (2) Point count method. For this purpose four-line transects and fourpoint counts were placed. For line transect, a straight line of about 1000 (m) in length and with 50 (m) radius on both sides of the line which is data collecting and observation range, while birds spotted outside this range were ignored. Each transect was traveled within 30 minutes covering the distance between two transects (about 1000m). Similarly, for point count, a circle of 50 (m) radius was placed. Inside this range, observations and data were recorded. At each point, observations were recorded for 10 min. The distance between the two points was about 1000 m. Survey and data were collected while following the rules and laws used by (Bibby et al., 2000;Khan and Gabol, 2021;Sadam et al., 2021Sadam et al., , 2022.

Identification of birds
Most birds were identified by direct observations in the field. However when facing some problems using equipment like binoculars (70 X 40mm) for observation and Digital cameras to take photographs to identify bird species (Umar et al., 2018). The two field guides were used for the identification of avian species: (1) Birds of Pakistan (Umar et al., 2018) and (2) Waterbirds of Asia (Bibi and Ali, 2013).

Statistical analysis
Collected data were arranged in an MS Excel sheet to analyze. One-way ANOVA and Shannon Diversity Index were applied each for comparison and diversity of bird species (Mahboob, 2009;Khan et al., 2022;Shuaib et al., 2021).

Bird diversity and deviation
In all selected habitats bird diversity and distribution were varied to some extent. Bird species were recorded in all habitats however, one of the three habitats had more diversity of bird species while the other two had less density. The most diverse habitat was Gharo Creek which had about 51% of bird species followed by scrubland about 27% and Bhambore fort terrestrial land about 21%. The most abundant order was Charadriiformes which had about 41 species (36.60%) followed by Passeriformes 30 species (26.78%). The remaining 13 orders ranged from 1-8 birds species, percentages ranging from 0.89-7.14 ( Table II). The most diverse and abundant bird species were Indian black-winged stilt (375), great egret (180), western reef egret (75), house sparrow (72), and Indian pond heron (65) (Table III). Similarly, based on seasonal status most abundant species were winter visitors (57), summer visitors (2), and vagrants (1) (Table IV).

Threats
The main threats faced by the birds were habitat destruction in the form of vegetation cutting and pollution, construction, and destruction which greatly disturbed the bird species. Illegal hunting and killing were rampant for various purposes like meat, plumage, and hunting purposes. Human interruption and disturbance in the form of grazing, wood collection, and general visiting to bird habitats play a key role in bird decline. Furthermore, drought and scarcity of feeding and foraging materials greatly affect birds. Waterbirds are largely affected by liquid effluents from boats and domestic wastewater.

DISCUSSION
The current research was conducted on the avian fauna of Gharo creek, district Thatta, Sindh, Pakistan O n l i n e

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Avian Diversity and its Threats in Gharo Creek 7 during the period April 2020 to March 2021. All the possible habitats, distribution, diversity of avian fauna, and threats explored. The highest number of species were recorded from order Charadriiformes followed by order Passeriformes. The birds near the bank of Creek were about 700 in number. In some habitats, single species were abundant while some species were in very low frequency because of their low density. Our result is similar to that of Ghalib et al. (2008). Umar et al. (2018) reported 670 bird species in Pakistan. Khan and Gabol (2021) reported 133 bird species in Balochistan. They also worked in the main jungle of Western Brazil where all the possible habitats were greatly affected by human interruptions and illegal activities greatly affects avian fauna. Our studied habitats have low agricultural lands, rapid urbanizations, and constructions. Secondly, the illegal hunting and fishing by locals greatly disturb the feeding and foraging activity of both local and migratory birds. Habitat degradation, hunting, disturbance, and drought-affected the avifauna of the area. Similarly, liquid effluents from boats, savage and other wastes are directly dumped in the water (Gharo Creek) and in surrounding which badly affect avifauna. Ghalib et al. (2008) reported that the overall numbers of water birds have fallen during recent years due to the degradation of wetlands, lack of management, disturbance, and environmental pollution including the effect of pesticides. Similarly, Ghalib et al. (2008) also reported the major threats to the shorebirds were habitat degradation, land reclamation, hunting, disturbance, and droughts.
In Gharo Creek deforestation of mangroves greatly affects avifauna. Mangroves prevent soil erosion, reduces the effects of flooding, etc. They also provide perching, foraging, and nesting sites to the avifauna especially the migratory birds belong to the orders Ciconiiformes, Charadriiformes, etc. Younas et al. (2017) reported that constructions of roads and factories decline the various flora as a source of habitat, feeding, and foraging activities for avian fauna. Similarly, Muzzafar (2000) reported that floral vegetation provides all the basic resources to various residential birds.
In the study area, dense forests and grasslands are present which provide nesting sites in trees as well on land. Except for mountainous habitats all the basic habitats were present which provide an aesthetic environment to avian fauna. Altaf et al. (2013) reported that bird species mostly depend on attractive habitats which fulfill all their basic life requirements. In the same way, Sadam et al. (2021) also reported the habitat and possible requirements of common birds of district Mardan. Sulieman et al. (2016) reported that urbanization and cutting of forests decline the attraction and habitats of common birds.
We were recorded more birds species in Gharo Creek (which consists of a water body) 51% followed by scrubland 27% and Bhambore fort 21%. Similarly, Luo et al. (2019) recorded most species 41% in habitat near a water body, and 14% species in habitats of scrubland.  also recorded more species in agricultural areas near urban areas. He also reported bird's species are more diverse and abundant in dense forests. Begum et al. (2016) reported 133 birds' species near the coastal and allied area of Balochistan.

CONCLUSION
The major threats to the avian fauna of gharo creek are habitat degradation, loss of habitat due to land reclamation, hunting, water pollution, and other anthropogenic activities.