Biodiversity of Earthworms with Special Reference to Tehsil Wazirabad, District Gujranwala, Punjab, Pakistan

Earthworms are crucial soil invertebrates that are involved in the circulation of nutrients, humus formation, decomposition of organic matter and generation of soil texture. They play an important role as bioindicator of soil contamination. Objective: To investigate the biodiversity of earthworms in different habitats (Grassy lawns, croplands, marshy areas, ponds, edges of river and canals) of Tehsil Wazirabad, Punjab, Pakistan. Methods : A total number of four hundred and �fty (450) samples of earthworms were collected from above mentioned sites for a period of six months (March 2015 to August 2015), by hand sorting technique. Morphological details of all earthworm specimens collected from the designated areas were recorded and species were identi�ed by using the systematic key. Results: During present investigation, six species; Pheretima posthuma, P. lignicola, P. morrisi, Microscolex dubis, Aporrectodea longa and Notoscolex sacutarius belonging to 4 genera and 2 families (Megascolecidae, Lumbricidae) were recorded. The distribution patterns of various earthworm species in the designated habitats shows that Pheretima posthuma is the most abundant species distributed in all sites; whereas, P. lignicola was least populated in the selected habitats. According to ecological grouping of reported earthworm species; Endogeic (50%) was the most dominant group followed by Epigeic (33%) and Anecic (17%). Conclusions: This study provided the base line data and much needed information about biodiversity of earthworms in Tehsil Wazirabad. This knowledge can be very useful in improving the soil conditions and agriculture gross production in investigated area.

Volume 5, Issue 1 (Jan-Mar 2024) ISSN (P): 2790-4377, (E):  Earthworms are the crucial constituent of animal biomass in soil ecosystems [1,2].They can be regarded as keystone species considering their contribution as ecosystem engineers, as they perform key role in managing soil richness, water in ltration, improving plant development through biogeochemical cycling and adjusting the greenhouse gas discharge [3][4][5][6].Through burrowing, throwing and mixing of soil with detritus (bioturbation) they alter the physicochemical properties of the upper layer of soil [7,8].Earthworms secrete variety of enzymes that change the chemical properties of different kinds of organic wastes [9].They are not only utilized in the making of medicines but also an important source of food for moles, birds, snakes and woodcocks [10,11].They are involved in transferring of waste energy from lower trophic levels to higher ones [12].Their in uence on any ecosystem is usually described by their soil tunneling activities and litter feeding [13].Ecosystems without earthworms exhibit slower degradation rate and thick layers of organic matter as compared to those ecosystems which are adapted to earthworms [14,15].Management of different earthworm populations is emerging as an important aspect for Copyright © 2024.Markhor, Published by Crosslinks International Publishers sustaining fertility and productivity of agro-ecosystems [16,17].The regional distribution pattern of earthworms (species dispersal and biodiversity) is greatly in uenced by several abiotic and biotic factors such as land management history, temperature, pH, human pressure, soil properties, humidity and organic matter inputs [18,19].Earthworms are generally categorized into three basic ecological and functional groups based on their burrowing behavior, feeding habits and reproductive strategies [14].(i) Epigeic species of earthworms inhabit and live on surface litter, (ii) Anecic species create deep vertical tunnels (2 meters) in mineral soil but feed on soil surface litter, (iii) Endogeic species construct horizontal burrows and feed mainly in the subsoil and rhizosphere [8].Considering their role in the stabilization of soil ecosystem, substantial attention is required for the exploration of population dynamics, distribution, biodiversity and community structure of earthworms.The present study was aimed to explore the diversity of earthworms and to identify various species collected from different habitats (croplands, grassy lawns, marshy areas, river banks, ponds and canal banks) of Tehsil Wazirabad, District Gujranwala.This is the rst survey in tehsil Wazirabad and this information will help us in improving the soil conditions and agriculture production in this area.

M E T H O D S
The present study was conducted in Tehsil Wazirabad.It is one of the four Tehsils of District Gujranwala in Punjab Province of Pakistan.It is situated at 32°26' North and 74°07' East on the banks of the river Chenab about 100 kilometers north of Lahore on the Grand Trunk Road [20].It is 45 kilometers away from Sialkot, 30 kilometers from the District Gujranwala and nearly twelve (12) kilometers from Gujrat.The climate of the Tehsil Wazirabad is hot semi-arid and uctuates throughout the year.The temperature of this area ranges between 44°C in summer to 7°C in winter.The highest precipitation is recorded from July to August during monsoon, whereas; the average rainfall is 25 millimeters per annum.In total seven sites of Tehsil Wazirabad were selected namely, Bella, Sohdra, Lawairi wala, Patoki, Talwara and Hari wala.The earthworm samples were collected from different habitats in these areas such as grassy lawns, croplands, marshy areas, ponds, edges of river and canals.These selected sites were visited many times for the sampling of earthworms.In total 450 earthworm samples were obtained from nominated sampling sites by simple hand sorting and digging method [21].One square foot (ft2) hole was dug with spade and scraper in each designated site and earthworms were taken.Specimen and habitat details were noted carefully.Then the collected earthworm samples were placed in jars.After collection, all specimens were brought in the research lab of Institute of Zoology, University of the Punjab, Lahore, Pakistan.After washing and cleansing with tap water earthworms were placed in 10% ethyl alcohol (10-15 minutes) for dehydration.For hardening and killing they were kept in formalin solution (10%) for 24 hours.Finally, samples were preserved in 5% formalin solution for detailed morpho-anatomical identi cation.Before preservation width and length of earthworms were calibrated and their color was noted.For the detailed examination of earthworms dissecting microscope and magnifying glass were used.Then preserved samples of earthworms were identi ed with the help of taxonomic keys and published literature [22][23][24][25].For identi cation, morphological characters such as shape of clitellum, color, shape of prostomium, position of spermatheca, number and position of genital papillae, position of dorsal pore, position of male pore, position of female pore were noted.Biodiversity of earthworms at all sites was assessed by Shannon-Weaver diversity index and Simpson index [26,27].All statistical analyses were performed by utilizing Microsoft Excel 2019 and SPSS version 21.0.

R E S U L T S
In the current study, we collected 450 earthworm samples from variety of areas of Tehsil Wazirabad, District Gujranwala, Punjab, Pakistan.We identi ed six (6) species of earthworms associated to four (4) genera and two (2) families (Table 1).

Species Genus
Identi cation (up to species level) was made possible by considering their morphological characters as listed in Table 2 with the help of above-mentioned identi cation keys and published literature Table 2: Taxonomic Characters of Identi ed Species of earthworms Pheretima posthuma (n=164) was observed as most prevalent earthworm species in all selected sites of Tehsil Wazirabad, whereas, Pheretima lignicola (n=17) was noted as least abundant species (Figure 1).Among the various visited habitats from 6 selected areas (Bella, Sohdra, Lawairi wala, Patoki, Talwara and Hari wala), maximum diversity of earthworms was recorded in grassy lawns (5 species), whereas, minimum diversity was observed at canal banks (2 species).Pheretima posthuma and Pheretima morrisi were discovered in all habitats (Table 3).The identi ed earthworm species were categorized into 3 ecological groups.Out of six (6) identi ed species, two (2) species were Epigeic (33%), three (3) species were endogeic (50%), whereas, only one species (17%) belonged to Anecic (Table 4).Present study provided the base line data and much needed information about biodiversity of earthworms in Tehsil Wazirabad.This knowledge can be very useful in improving the soil conditions and agriculture gross production in investigated area.Among the six identi ed species Pheretima posthuma was noted as the most abundant species present in all kinds of habitats.Grassy lawns and home gardens proved to be very productive areas for the earthworms.Further investigations are required to explore the biodiversity of earthworms in different areas of Pakistan.

Figure 1 :
Figure 1: Relative abundance of earthworm species collected from Tehsil Wazirabad

Pheretima ( 3
was observed as the most diverse genus while, other 3 genera were recorded with one species each (Figure2).

Table 1 :
List of earthworm species identi ed from Tehsil Wazirabad, Pakistan

Table 3 :
Species diversity of earthworms in various habitats.