Ecological Assortment of Snakes in Southern Punjab, Pakistan

Zahid Farooq1, Sufi Muhammad Akram2, Muhammad Saleem Khan3,* and Muhammad Wajid4

1Deputy Director Research, Punjab Wildlife Research Institute, Gatwala, Faisalabad,

2Department of Zoology, Government College, Satiana Road, Faisalabad, Pakistan

3Department of Zoology, Government College University, Faisalabad, Pakistan

4Department of Biological Sciences, University of Okara, Pakistan

ABSTRACT

Snakes captured, dead or alive, from different habitats of the southern Punjab, Pakistan, were identified based on external morphological features. Total 521 specimens collected/captured belonged to 5 families, 16 genera and 25 species. Indian cobra (Naja naja) (8.83%; N = 46), Glossy-bellied racer (Coluber ventromaculatus) (7.87%; N = 41) and Common krait (Bungarus caeruleus) (7.49%; N = 39) were higher in prevalence. Northern wolf snake (Lycodon striatus striatus), Sind long-nose sand snake (Lytorhynchus paradoxus) and Afghan awl-head snake (L. ridgewayi) (0.38%; N = 2) were the least abundant. Snakes were more frequent in croplands and least frequent in barren areas.

Article Information

Received 27 July 2016

Revised 23 March 2017

Accepted 28 July 2017

Available online 18 January 2018

Authors’ Contribution

ZH designed and performed the experiment. SMA and MW participated in identification of snakes. MSK collected, complied and analyzed the data and worte the manuscript.

Key words

Snakes, Indian cobra, Glossy-bellied racer, Wolfsnake, Sind long nose sand snake, Owl-head snake.

DOI: http://dx.doi.org/10.17582/journal.pjz/2018.50.1.sc9

* Corresponding author: samiikhan@yahoo.com

0030-9923/2018/0001-0397 $ 9.00/0

Copyright 2018 Zoological Society of Pakistan

Snakes are valuable for humanity. Snakes play an important role in the conservation and formation of soil (Shine, 1995; Farooq et al., 2007) by controlling agricultural pests thus increasing productivity of agricultural fields.

Diversity of snakes is not fully explored in Pakistan. Pakistan has world’s three of the eight bio-geographic realms (Indo-Malayan, Palearctic and Africo-tropical Realms), four of the world’s ten ‘biomes’ (desert, temperate grassland, tropical seasonal forest and mountain Biomes) and three of the world’s four ‘domains’ (polar/montane, humid temperate and dry Domains) (Roberts, 2005). Biodiversity, at all levels, is continuously under threat in Pakistan due to unwise management of community structure, and the development of higher yielding varieties of agricultural crops to feed the rapidly increasing human population (Chaudhry et al., 1999). The use of chemicals and sprays has increased manifold during recent years causing serious threat to soil fauna. Combination of all these factors affects the habitat quality significantly (Akram and Qureshi, 1995; Farooq et al., 2007).

Snake fauna record in Pakistan has not been updated for some decades, on the basis of ecology, taxonomy and their distribution (Farooq et al., 2007). The present study was conducted to describe the ecological assortment of snakes of southern Punjab, Pakistan. Such local studies are important for compiling a more comprehensive faunal picture of the country.

Materials and Methods

The southern Punjab (28.20o-31.02’ N, 69.25o-73.12’ E; area 105,504 km2) is administratively divided into three civil divisions viz., Bahawalpur, Multan and DG Khan. Based on topography, parent soil material and vegetation structure, the land of southern Punjab can be divided into croplands, natural forests, irrigated forest plantations, riverine forest/areas and desert areas.

The mean annual rainfall varies from 100 mm in the west to 250 mm in the east, chiefly falling during summer monsoon (July- September). Duration and frequency of rainfall are very inconsistent (Salma et al., 2012). The mean summer temperature ranges between 38-40 °C (may shoot up to 54.6 °C) while mean winter temperature lies between 14- 16 °C (Khattak and Ali, 2015).

Snakes were collected dead or alive (captured with snake stick and anesthetized/ killed with chloroform) from different localities with the help of local farmers and villagers. The dead specimens were preserved in 10% formalin, identified to species level using available keys (Minton, 1962; Mertens, 1971; Khan and Mirza, 1977; Khan, 1983; Khan and Baig, 1988; Akram and Qureshi, 1995; Farooq et al., 2007). Each specimen was sexed and broad habitat of collection place was noted.

Collected data were analyzed statistically following Steel and Torrie (1960).

Results and discussion

We collected 521 snake specimens, falling in 5 families, 16 genera and 25 species (Table I). Maximum relative abundance was recorded for family Colubridae

Table I.- Relative abundance, sex ratio, diversity, evenness, dominance and richness of snake species in southern Punjab.

(63.53%: N = 331), and minimum for family Boidae (6.53%: N = 34). Indian cobra Naja naja naja (8.83%, N = 46; family Elapidae), Gray’s rat snake Coluber ventromaculatus (7.87%, N = 41; family Colubridae), Common krait Bungarus caeruleus (7.49%, N = 39; family Elapidae) and Checkered keel- back Xenochrophis piscator piscator (7.29%, N = 38; family Colubridae) were the most abundant and diversified species, whereas Northern wolf snake Lycodon striatus striatus, Sindh long-nose sand snake Lytorhynchus paradoxus and Afghan awl-head snake L. ridgewayi (0.38%; N = 2, family Colubridae) were the least abundant. Variations in abundance could be ascribed to nature of habitat (Pauwels et al., 2008), structure of canopy (important for natural refuges) and type of vegetation (Amr, 2008). Earlier similar findings have been recorded by Khan and Baig (1988), Akram and Qureshi (1995) and Farooq et al. (2007) for various regions of Pakistan.

The highest diversity was recorded for family Elapidae (0.2958) and minimum for family Boidae (0.1781). Diversity was the highest for Indian cobra (0.2143) and lowest for Northern wolf snake, Sindh longnose sand snake and Afghan awl-head snake (0.0214). Evenness was the maximum for family Elapidae (0.1533) and the least for family Colubridae (0.1144). At species level, it was the maximum for Indian cobra (0.1289) and lowest for Northern wolf snake, Sindh longnose sand snake and Afghan awl-head snake (0.0709). Dominance was the highest for family Colubridae (0.8856) and the lowest for family Elapidae (0.8467) whereas, at species level it was the maximum for Russell’s boa or Rough-scaled sand boa Gangylophis conicous (0.9379) and the lowest for Glossy-bellied racer (0.8760). Richness was the maximum for

Table II.- Relative distribution of different snake species in different habitats and administrative divisions.

family Boidae (7.0895) and minimum for family Colubridae (4.3088). Sand snake Psammophis condanarus, Northern wolf snake, Sindh long-nose sand snake and Afghan awl-head snake exhibited the same higher richness values (36.0674); while Glossy-bellied racer (6.7321) held minimum richness (Table I). Similar findings of richness values were reported by Khan and Baig (1988), Akram and Qureshi (1995), Farooq et al. (2007), Pauwels et al. (2008) and Amr and Disi (2011).

Habitat comprises of desert area with small plantation, shallow water bodies, lose soil, croplands, bare soil with small vegetation, barren area with thick plantations (non-cultivated area), and housing settlements near croplands area.

Maximum snake population was recorded in croplands (25%), followed by deserts with low vegetation (25%), bare soil with sparse short vegetation (23%) (Table II).

High cropping density, deserts with sparse short vegetation (Akram and Qureshi, 1995; Farooq et al., 2007) and bare soil with sparse short vegetation (Amr and Disi, 2011) provide perfect natural camouflaging habitat for a snake. Floor and dense canopy is a suitable habitat for snakes. In contrast, lowest population was recorded from shallow water bodies, loose soil, house gardens/ lawns (4%) and barren areas with plantation (2%). In such areas, human interference was higher, not preferred by snakes (Amr, 2008; Al-Quran, 2009; Amr and Disi, 2011). Moderate population was present in human settlements near crops (13%); snakes from crops of nearby fields visit human settlements for food and if proper refuge is available the snakes start living there (El Din, 2006).

Population abundance was compared between three administrative divisions to evaluate the role of topography and farm habitat for future conservation of snakes (Table II). Dera Ghazi Khan and Bahawalpur Divisions held equal abundance (37-38%). These tracts include bare soil with short vegetation, desert with small vegetation, lose soil; all providing suitable habitat and camouflage for snakes (Akram and Qureshi, 1995; Farooq et al., 2007; Amr and Disi, 2011). Multan Division held lower snake abundance (25%), attributable to higher human interference and higher use of pesticides (Al-Quran, 2009; Amr and Disi, 2011).

During the present study, it was concluded that intensive deforestation, expansion of agriculture and increased urbanization were major causes of snake population decline (Stuart et al., 2000). Along with these issues, use of snakes as food in some human communities was another threat to their abundance (Zhou and Jiang 2005) but this issue is not faced in Pakistan. Herpetological research needs to be strengthened to recommend/adopt measures for the conservation of snake fauna. Alteration/ destruction of habitat should be reduced up to ETL (economic threshold level) especially around the newly settled colonies to save snakes from decline.

Acknowledgment

The authors are grateful to the Punjab Wildlife & Parks Department for providing the facility, space and time to complete this study. The authors are also grateful to the Department of Biological Sciences, University of Okara, Okara, Pakistan for providing laboratory facilities.

Statement of conflicts of interest

Authors declare that they have no conflict of interest.

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