Seasonal dynamics of soil microbial biomass in fragmented patches of subtropical humid forest of Jaintia hills in Meghalaya, Northeast India

Ngakhainii Trune Pao, Krishna Upadhaya


Aim of the study: The aim of the study was to assess the seasonal dynamics of microbial biomass and its contribution to soil system along a fragment size gradient in subtropical humid forest of Meghalaya.  

Area of study: The study was conducted in forest fragments located at Jarain and adjoining areas in Jaintia Hills of Meghalaya, northeast India.

Material and Methods: Forest fragments of sizes ranging from 3.8 to 105 ha were selected for the study and grouped into Small (< 5 ha), Medium (> 5 and < 15 ha), Large (>15 and < 50 ha) and Very Large (105 ha) classes. Three experimental plots each of 20 x 20 m were established at the forest edge and at 50 m distance assigned as ‘interior’ microsite in each of the fragments for sampling of soil. Soil samples (0-10 cm depth) from each of the experimental plots were collected in replicates on seasonal interval and microbial biomass was estimated by the fumigation extraction method.

Important findings: Microbial biomass- C, -N and -P varied significantly (p< 0.05) between the fragment sizes, microsites and seasons. The microbial biomass was higher in the interior as compared to the edge. It was also high during the winter season. Overall, soil microbial biomass -C, -N and -P ranged from 260 to 969; 25 to 95 and 8 to 67 µg g-1 respectively. The contribution of microbial biomass -C, -N and -P to soil organic carbon, total Kjeldahl nitrogen and phosphorus ranged from 1.48 to 1.81 %, 2.54 to 4.54 % and 3.41 to 5.22 % respectively. Fragmentation alters the microenvironmental conditions and soil properties that in turn affect the microbial biomass. 

Highlights: This interaction of plant, soil and microbial community would gradually degrade in the fragments due to change in vegetation composition and structure, microclimatic conditions and soil physical and chemical properties. Our results suggests that microbial mediated ecosystem processes such as nutrient cycling are more susceptible to variation at the edge which may become unstable and unpredictable in forest fragments exposed to various human disturbances.

Keywords: fragment size, microbial biomass, microenvironment, subtropical forest.

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Allen SE, Grimshaw HM, Parkinson JA, Quarmby C, 1974. Chemical Analysis of Ecological Materials. London: Blackwell Scientific Publication.

Anderson JM, Ingram JSI, 1993. Tropical Soil Biology and Fertility. A Handbook of Methods. U.K.: CAB International, Wallingford.

Arunachalam K, Arunachalam A, Melkania NP, 1999. Influence of soil properties on microbial populations, activity and biomass in humid subtropical mountainous ecosystems of India. Biol Fert Soils 30(3): 217-223.

Barbhuiya AR, Arunachalam A, Pandey HN, Arunachalam K, Khan ML, Nath PC, 2004. Dynamics of soil microbial biomass C, N and P in disturbed and undisturbed stands of a tropical wet-evergreen forest. Europ J Soil Biol 40: 113-121.

Barbhuiya AR, Arunachalam A, Pandey HN, Khan ML, Arunachalam K, 2008. Effects of disturbance of fine roots and soil microbial biomass C, N and P in a tropical rainforest ecosystem of Northeast India. Curr Sci 94(5): 572-574.

Bierregaard Jr RO, Lovejoy TE, Kapos V, Santos AA dos, Hutchings RW, 1992. The biological dynamics of tropical rainforest fragments. BioScience 42: 859 - 866.

Brookes PC, Powlson DS, Jenkinson DS, 1982. Measurement of microbial phosphorus in the soil microbial biomass. Soil Biol Biochem 14: 319-329.

Brookes PC, Landman A, Pruden G, Jenkinson DS, 1985. Chloroform fumigation and the release of soil nitrogen: a rapid direct extraction method to measure microbial biomass nitrogen in soil. Soil Biol Biochem 17: 837-847.

Brothers TS, Spingarn A, 1992. Forest fragmentation and alien plant invasion of Central Indiana old-growth forests. Conserv Biol 6: 91-100.

Brume R, Khanna PK, 2009. Functioning and Management of European Beech Ecosystems. Springer.

Burton J, Chen C, Xu Z, Ghadiri H, 2010. Soil microbial biomass, activity and community composition in adjacent native and plantation forests of subtropical Australia. J Soil Sediments 10: 1267 - 1277.

Camargo JLC, Kapos V, 1995. Complex edge effects on soil moisture and microclimate in central Amazonian forest. J Trop Ecol 11:205–211.

Central Ground Water Board, 2013. Ground Water Information Booklet Jaintia Hills District, Meghalaya. Ministry of Water Resources, Government of India. Technical Report Series 49/2011-2012.

Champion HG, Seth SK, 1968. A Revised Survey of Forest Types of India, New Delhi, Government of India Press.

Chen F, Peng X, Zhao P, Yuan J, Zhong C, Cheng Y, Cui C, Zhang S, 2013. Soil microbial biomass, basal respiration and enzyme activity of main forest types in the Qinling mountain. PLOS ONE 8(6): 1 - 12.

Chen J, Saunders SC, Crow TR, Naiman RJ, Brosofske KD, Mroz GD, Brookshire LB, Franklin JF, 1999. Microclimate in forest ecosystem and landscape ecology. BioScience 49(4): 288 - 297.

Chen T, Chiu C, Tian G, 2005. Seasonal dynamics of soil microbial biomass in coastal sand dune forest. Paedobiologia 49: 645-653.

Das AK, Boral L, Tripathi RS, Pandey HN, 1997. Nitrogen mineralization and microbial biomass-N in a subtropical humid forest of Meghalaya, India. Soil Biol Biochem 29(9/10): 1609-1612.

Devi NB, Yadava PS, 2006. Seasonal dynamics in soil microbial biomass C, N and P in a mixed-oak forest ecosystem of Manipur, North-east India. Applied Soil Ecol 31: 220-227.

Diaz-Raviña M, Acea MJ, Carballas T, 1993. Seasonal fluctuations in microbial populations and available nutrients in forests soil. Biol Fertil Soil 16: 205-210.

Diaz-Raviña M, Acea MJ, Carballas T, 1995. Seasonal change in microbial biomass and nutrient flush in forests soils. Biol Fertil Soil 19: 220-226.

Flores-Renteria D, Yuste JC, Rincon A, Brearley FQ, Garcia-Gil JC, Vallardes F, 2015. Habitat fragmentation can modulate drought effects on the plant-soil-microbial system in Mediterranean holm oak (Quercus ilex) forests. Microb Ecol 69(4): 798 - 812.

Haddad NM, Brudvig LA, Clobert J, Davies KF, Gonzalez A, Holt RD, Lovejoy TE, Sexton JO, Austin MP, Collins CD et al., 2015. Habitat fragmentation and its lasting impact on earth's ecosystem. Science Advances 1(2):e1500052.

Ibanez I, Watz DSW, Pelteir D, Wolf SM, Barrie TC, 2014. Assessing the integrated effects of landscape fragmentation on plants and plant communities: the challenge of multiprocess-multiresponse dynamics. J Ecol 102: 882-895.

Jose S, Gillespie AR, George SJ, Kumar M, 1996. Vegetation responses along edge-to-interior gradients in a high altitude tropical forest in peninsular India. For Ecol Manag 87: 51-72.

Kamei J, 2007. Studies on interrelationship between tree diversity and N and P Dynamics in a humid Subtropical forest ecosystem of Meghalaya. PhD Thesis, Shillong, North-Eastern Hill University.

Laurance WF, Fearnside PM, Laurance SGW, Delamonica P, Lovejoy TE, Rankinde Merona JM, Chambers JQ, Gascon C, 1999. Relationship between soils and Amazon forest biomass: a landscape-scale study. For Ecol Manag 118: 127 - 138.

Laurance WF, Andrade AS, Magrach A, Camago JLC, Campbell M, Fearnside PM, Edwards W, Valsko JJ, Lovejoy TES, Laurance SG, 2014. Apparent environmental synergism drives the dynamics of Amazonian forest fragments. Ecology 95: 3018 - 3026.

Laurance WF, Ferreeira LV, Rankin-de Merona JM, Laurance SG, 1998. Rainforest fragmentation and the dynamics of Amazonian tree communities. Ecology 79: 2032 - 2040.[2032:RFFATD]2.0.CO;2

Laurance WF, Laurance SGW, Ferreeira LV, Rankin-de Merona JM, Gascon C, Lovejoy TE, 1997. Biomass collapse in Amazonian forest fragments. Science 278: 1117 - 1118.

Laurance WF, Delamonica P, Laurance SGW, Vasconcelos HL, Lovejoy TE, 2000. Rainforest fragmentation kills big trees. Nature 404: 836.

Lázaro-Nogal A, Matesanz S, Gimeno TE, Escudero A, Valladares F, 2012. Fragmentation modulates the strong impact of habitat quality and plant cover on fertility and microbial activity of semiarid gypsum soils. Plant Soil 358: 213-223.

Maithani K, Tripathi RS, Arunachalam A, Pandey HN, 1996. Seasonal dynamics of microbial biomass C, N and P during regrowth of a disturbed subtropical humid forest in north-east India. Applied Soil Ecol 4(1): 31-37.

Moreno ML, Bernaschini ML, Prez-Harguindeguy N, Vallardes G, 2014. Area and edge effects on leaf-litter decomposition in a fragmented subtropical dry forest. Acta Oecologia 60: 26-29.

Pao NT, Upadhaya K, 2017. Effect of fragmentation and anthropogenic disturbances on floristic composition and structure of subtropical broad leaved humid forest in Meghalaya, northeast India. Applied Ecol Environm Res 15(4):385-407.

Pao NT, Upadhaya K, Mir AH, 2016. Phenological behaviour of tree species in subtropical broadleaved humid forests of Jaintia Hills in Meghalaya, northeast India. Int Res J Biolog Sci 5(7): 10-15.

Ruitta T, Slade EM, Bebber DP, Taylor ME, Malhi Y, Riordan P, Macdonald DW, Morecroft MD, 2012. Experimental evidence for the interacting effects of forest edge, moisture and soil moisture on leaf decomposition. Soil Biol Biochem 49: 124 - 131.

Schloter M, Dilly O, Munch JC, 2003. Indicators for evaluating soil quality. Agric, Ecosyst Environ 98: 255-262.

Singh JS, Kashyap AK, 2006. Dynamics of viable nitrifier community, N-mineralization and nitrification in seasonally dry tropical forests and savanna. Microbial Res 161:169-179.

Singh JS, Raghubanshi AS, Singh RS, 1989. Microbial biomass acts as a source of plant nutrients in dry tropical forest and savanna. Nature 338(6215): 499-500.

Singh JS, Singh DP, Kashyap AK, 2010. Microbial biomass C, N and P in dry tropical forest soils. Pedosphere 20(6): 780-788.

Sizer NC, Tanner EVJ, Ferraz IDK, 2000. Edge effects on litterfall mass and nutrient concentration in forest fragments in central Amazonia. J Trop Ecol 16(8): 853 - 863.

Theng BKG, Tata KR, Sollins P, 1989. Constituents of organic matter in temperate and tropical soils. In: Dynamics of Soil Organic Matter in Tropical Ecosystems eds. Coleman DC, Oades JM, Uehera G. pp.5-32. Honolula, University of Hawaii Press.

Toledo-Aceves T, Garcia-Oliva F, 2008. Effect of forest pasture edge on C, N and P associated with Caesalpinia eriostachys a dominant tree species in a tropical deciduous in Mexico. Ecolog Restor 23: 271-280.

Upadhaya K, Pandey HN, Tripathi RS, 2006. Effect of anthropogenic disturbances on soil microbial biomass carbon in sacred groves of Jaintia hills in Meghalaya. Indian J Soil Conserv 34 (3): 221-225.

Vance ED, Brookes PC, Jenkinson DS, 1987. An extraction method for measuring soil microbial biomass. Soil Biol Biochem 19: 703-707.

Wang X, Wang X, Zhang W, Shao Y, Zou X, Liu T, Zhou L, Wan S, Rao X, Li Z et. al., 2016. Invariant community structure of soil bacteria in subtropical coniferous and broadleaved forests. Scientific Reports, 1-11. doi: 10.1038/ srep19071.

Xing S, Chen C, Zhou B, 2010. Soil soluble organic nitrogen and active microbial characteristics under adjacent coniferous and broadleaf plantation forests. J Soils Sediments 10:748-757.

Yeong KL, Reynolds G, Hill JK, 2016. Leaf litter decomposition in degraded and fragmented tropical rain forests of Borneo. Biotropica 48(4): 443-452.

Zhu H, Xu ZF, Wang H, Li BG, 2004. Tropical rain forest fragmentation and its ecological and species diversity changes in southern Yunnan. Biodiv Conserv 13: 1355 - 1372.

DOI: 10.5424/fs/2019281-13972