바로가기메뉴

본문 바로가기 주메뉴 바로가기

logo

Prosopis juliflora invasion and environmental factors on density of soil seed bank in Afar Region, Northeast Ethiopia

Journal of Ecology and Environment / Journal of Ecology and Environment, (P)2287-8327; (E)2288-1220
2019, v.43 no.4, pp.400-420
https://doi.org/10.1186/s41610-019-0133-4
Wakshum Shiferaw (Arba Minch University)
Tamrat Bekel (Addis Ababa University)
Sebsebe Demissew (Addis Ababa University)
Ermias Aynekulu (The World Agroforestry Centre (ICRAF))
  • Downloaded
  • Viewed

Abstract

The aims of the study were to analyze (1) the effects of Prosopis juliflora (Prosopis) on the spatial distribution and soil seed banks (SSB) diversity and density, (2) the effects of environmental factors on SSB diversity and density (number of seeds in the soil per unit area), and (3) the effects of animal fecal droppings on SSB diversity, density, and dispersal. Aboveground vegetation data were collected from different Prosopis-infested habitats from quadrats (20 × 20 m) in Prosopis thickets, Prosopis + native species stand, non-invaded woodlands, and open grazing lands. In each Prosopis-infested habitats, soil samples were collected from the litter layer and three successive soil layer, i.e., 0–3 cm, 3–6 cm, and 6–9 cm. Seeds from soil samples and animal fecal matter were separated in the green house using the seedling emergence technique. Invasion of Prosopis had significant effects on the soil seed bank diversity. Results revealed that the mean value of the Shannon diversity of non-invaded woodlands was being higher by 19.2%, 18.5%, and 11.0% than Prosopis thickets; Prosopis + native species stand and open grazing lands, respectively. The seed diversity and richness, recovered from 6–9-cm-deep layer were the highest. On the other hand, the density of Prosopis seeds was the highest in the litter layer. About 156 of seeds/kg (92.9%) of seeds were germinated from cattle fecal matter. However, in a small proportion of seedlings, 12 of seeds/kg (7.1%) were germinated from shot fecal matter. Thus, as the seeds in the soil were low in the study areas, in situ and ex situ conservation of original plants and reseeding of persistent grass species such as Cynodon dactylon, Cenchrus ciliaris, Chrysopogon plumulosus, and Brachiaria ramosa are recommended.

keywords
Afar, Density, Pastoralists, Prosopis juliflora, Rangeland, Soil seed bank

Reference

1.

Abebe Y (2012). Ecological and economic dimensions of the paradoxical invasive species—Prosopis juliflora and policy challenges in Ethiopia, J Econ Sustainable Dev ISSN 2222-1700, 3(8), ISSN 2222-2855, www.iiste.org.

2.

Abella SR, Chiquoine LP, Vanier CH (2013). Characterizing SBs and relationships to plant communities. Plant Ecology, 214 (5), Available at: https://www.jstor.org/stable/23500356.

3.

Arevalo-Sandi A, Bobrowiec PED, Rodriguez Chuma VJU, Norris D. Diversity of terrestrial mammal seed dispersers along a low land Amazon forest regrowth gradient. PLoS ONE. 2018;13(3):e0193752. https://doi.org/10.1371/journal.pone.0193752.

4.

Argaw M, Teketay D, Olsson M (1999) Soil seed flora, germination and regeneration pattern of woody species in an Acacia woodland of the Rift Valley in Ethiopia. J Arid Environ 43: 411–435 Available online at http://www.idealibrary.com

5.

Ayanu Y, Anke J, Detlef M. Ecosystem engineer unleashed: Prosopis juliflora threatening ecosystem services? Regional Environ Change. 2015;15:155–67. https://doi.org/10.1007/s10113-014-0616-x.

6.

Bekele T. Plant population dynamics of Dodonaea angustifolia and Olea europaea spp. cuspidata in dry Afromontane Forests of Ethiopia, (Ph.D. Thesis). Acta Universitatis Upsaliensis, Uppsala, 2000;559.

7.

Berhanu A, Tesfaye G. The Prosopis juliflora dilemma, impact on dryland biodiversity and some controlling methods. J Dry Lands. 2006;1(2):158–64.

8.

Bilal MA (2015). A review of endozoochorous seed dispersal by herbivores and its potential effects on seed germination. MSc Thesis, Norwegian University of Life Sciences, As, Norway https://brage.bibsys.no/xmlui/bitstream/handle/11250/2384014/

9.

Biswas SR, Malik AU. Disturbance effects on species diversity and functional diversity in riparian and upland plant communities. Ecology. 2010;91(1):28–35.

10.

Bruun HH, Poschlod P (2006). Why are small seeds dispersed through animal guts: large numbers or seed size per se? Oikos 113: 402-411.Publishing, Ltd.

11.

Bueno A, Baruch Z. Soil seed bank and the effect of needle litter layer on seedling emergence in a tropical pine plantation. Rev. Biol. Trop. (Int. J. Trop. Biol). 2011;59(3):1071–9. https://doi.org/10.15517/rbt.v0i0.3379.

12.

Central Statistical Agency (CSA) (2013). Population projection of Ethiopia for all regions at district Level, Addis Ababa, Ethiopia.

13.

Chaideftou E, Thanos CA, Bergmeier E, Kallimanis A, Dimopoulos P. Seed bank composition and aboveground vegetation in response to grazing in sub-Mediterranean oak forests (NW Greece). Plant Ecology. 2009;201:255–65. https://doi.org/10.1007/s11258-008-9548-1.

14.

Chapman JI, McEwan RW. The role of environmental filtering in structuring Appalachian Tree Communities: topographic influences on functional diversity are mediated through soil characteristics. Forests. 2018;9(19):1–16. https://doi.org/10.3390/f9010019.

15.

Cheng ER, Jefferies RL, Carleton TJ. The relationship between vegetation and soil seed banks in an arctic coastal marsh. J Ecol. 2001;89:367–84.

16.

Cox RD, Allen EB. The composition of soil seed banks in southern California coastal sage scrub and adjacent exotic grassland. Plant Ecol. 2007;198:37–46. https://doi.org/10.1007/s11258-007-9383-9.

17.

Cox RD, Allen EB. The composition of soil seed banks in southern California coastal sage scrub and adjacent exotic grassland. Plant Ecol, 2008:198:37–46, https://doi.org/10.1007/s11258-007-9383-9.

18.

da Luz GR, Mota GD, Spadeto C, Tolentino GS, Fernandes GW, Nunes YRF. Regenerative potential of the soil seed bank along an elevation gradient of rupestrian grassland in southeastern Brazil. Botany. 2017;96:281–98. https://doi.org/10.1139/cjb-2017-0162.

19.

Dalle G, Brigitte LM, Johannes I. Encroachment of woody plants and its impact on pastoral livestock production in the Borana lowlands, southern Oromia, Ethiopia, East African Wild Life Society. Afr J Ecol. 2006;44:237–46.

20.

Dalling JW, Swaine MD, Garwood NC. Effect of soil depth on seedling emergence in tropical soil seed-bank investigations. Functional Ecol. 1995;9:119–21 http://www.jstor.org.

21.

Dessalegn KT (2010). Assessment of rangeland degradation, its effect on soil seed bank flora and implications on carbon sequestration. A case study of Allaidege rangeland, Afar Region, Ethiopia, MSc Thesis, Haramaya University, pp22-139.

22.

Dreber N. How best to quantify soil seed banks in arid rangelands of the Nama Karoo? Environ Monit Assess. 2011;173:813–824. https://doi.org/10.1007/s10661-010-1425-4.

23.

Duncan RP, Diez JM, Sullivan JJ, Wangen S, Miller AL. Safe sites, seed supply, and the recruitment function in plant populations. Ecology. 2009;90:2129–38.

24.

Eager EA, Haridas CV, Pilson D, Rebarber R, Tenhumberg B. Disturbance frequency and vertical distribution of seeds affect long-term population dynamics: a mechanistic seed bank model. Am Naturalist. 2013;182(2). https://doi.org/10.1086/670987.

25.

Egawa C, Tsuyuzaki S. The effects of litter accumulation through succession on seed bank formatiom for small- and large-seeded species. Journal of Vegetation Sciences. 2013;24:1062-1073. https://doi.org/10.1111/jvs.12037.

26.

El-Keblawy A (2012). Impacts of Native and Exotic Prosopis Species on Native Plants in Aridlands of the UAE, International Conference on Ecology, Agriculture and Chemical Engineering (ICEACS’2012), Phuket, Thailand.

27.

El-Keblawy A, Al-Rawai A. Impacts of the invasive exotic Prosopis juliflora (Sw.) D. C. on the native flora and soils of the UAE. Plant Ecology. 2007;190:23–35. https://doi.org/10.1007/s11258-006-9188-2.

28.

Espinosa CI, Luzuriaga AL, Cruz MD, Montero M, Escudero A. Co-occurring grazing and climate stressors have different effects on the total seed bank when compared to the persistent seed bank. J Vegetation Sci. 2013;24:1098–107.

29.

FAO (2006). Invasion of Prosopis juliflora in India, In Problems posed by the introduction of Prosopis species in selected countries, Italy Rome, p13.

30.

Fengqin J, Tashpolat T, Nan W, Changyan T, Yuanming Z. Characteristics of soil seed banks at different geomorphic positions within the longitudinal dunes of the Gurbantunggut Desert, China. J Arid Land. 2017;9(3):355–67. https://doi.org/10.1007/s40333-017-0055-x.

31.

Friis I, Demissew S, Breugel PV. Atlas of potential vegetation of Ethiopia. Royal Danish Acad Sci Lett Biol Skrifter. 2010;58:1–315.

32.

Gairola S, Sharma CM, Ghildiyal SK, Suyal S. Regeneration dynamics of dominant tree species along an altitudinal gradient in moist temperate valley slopes of the Garhwal Himalaya. Journal of Forestry Research. 2012;23(1):53–63. https://doi.org/10.1007/s11676-012-0233-9.

33.

Gautam MK, Kumar RM, Kumar AT. Patterns of diversity and regeneration in unmanaged moist deciduous forests in response to disturbance in Shiwalik Himalayas, India. J Asia-Pacific Biodivers. 2016;9:144–51.

34.

Getachew S, Demissew S, Woldemariam T. Allelopathic effects of the invasive Prosopis juliflora (Sw.) DC on Selected Native Plant Species in Middle Awash, Southern Afar Rift of Ethiopia. Manag Biol Invasions. 2012;3(2):105–14. https://doi.org/10.3391/mbi.2012.3.2.05.

35.

Gioria M, Pysek P. The legacy of plant invasions: changes in the soil seed bank of invaded plant communities. Bioscience. 2016;66(1):40–53. https://doi.org/10.1093/biosci/biv165.

36.

Gonzalez SL, Ghermandi L. Comparison of methods to estimate soil seed banks: the role of seed size and mass. Commun Ecol. 2012;13(2):238–42.

37.

Gul B, Ansari R, Flowers TJ, Khan AM. Germination strategies of halophyte seeds under salinity, Environmental and Experimental Botany; 2012. http://dx.DOI.org/10.1016/j.envexpbot.2012.11.006.

38.

Haji J, Mohammed A. The economic impact of Prosopis juliflora on agropastoral households of Dire Dawa Administration, Ethiopia. Afr J Agric Res. 2013;8(9): 768–79. https://doi.org/10.5897/AJAR12.014.

39.

Hadera G. A study on the ecology and management of the Dessa forest in the northeastern escarpment of Ethiopia. Unpublished MSc Thesis Addis Ababa University, 2000.

40.

Hopfensperger N. A review of similarity between seed bank and standing vegetation across ecosystems. Oikos. 2007;116:1438–48. https://doi.org/10.1111/j.2007.0030-1299.15818.x.

41.

IBM Corporation (1986, 2016). IBM SPSS Statistics 24 Core System User’s Guide, USA printing.

42.

Ilukor J, Rettberg S, Treydte A and Birner R (2016). To eradicate or not to eradicate? Recommendations on Prosopis juliflora management in Afar, Ethiopia, from an interdisciplinary perspective, Policy and Practice 6:14 https://doi.org/10.1186/s13570-016-0061-1

43.

Kaur R, Gonzales WL, Llambi LD, Soriano PJ, Callaway RM, Rout ME, Gallaher TJ, Inderjit. Community Impacts of Prosopis juliflora Invasion: Biogeographic and Congeneric Comparisons. PLoS ONE. 2012;7(9):e44966. https://doi.org/10.1371/journal.pone.0044966.

44.

Kebede AT. Sustaining the Allideghi Grassland of Ethiopia: Influence of Pastoralism and Vegetation Change, All Graduate Theses and Dissertations, Paper 309; 2009. http://digitalcommons.usu.edu/etd/309.

45.

Kellerman MJS, Van Rooyen M. Seasonal variation in soil seed bank size andspecies composition of selected habitat types in Maputaland, South Africa. Bothalia. 2007;37(2):249–258.

46.

Kent M, Coker P. Vegetation descriPJTion and analysis: A practical approach, England; 1992:97.

47.

Koch MA, Scheriau C, Schupfner M, Bernhardt KG. Long term monitoring of the restoration and development of limestone grasslands in northwestern Germany: vegetation screening and soil seed bank analysis. Flora. 2011;206:52–65.

48.

Kumar S, Mathur M. Impact of invasion by P. juliflora on plant communities in arid grazing lands, Tropical Ecology. 2014;55(1):33–46.

49.

Li CD, Xiao B, Wang Q, Zheng R, Wu J (2017). Responses of SB and vegetation to the increasing intensity of human disturbance in a semi-arid region of Northern China. Sustainability, 9: 1837, https://doi.org/10.3390/su9101837.

50.

Li Q, Fang H, Cai Q. Persistent soil seed banks along altitudinal gradients in the Qilian Mountains in China and their significance for conservation management. Af J Agric Res. 2011;6(10):2329–40. https://doi.org/10.5897/AJAR10.1099.

51.

Limenih M, Teketay D. Changes in soil seed bank composition and density following deforestation and subsequent cultivation of tropical dry Afromontane forest in Ethiopia. Journal of Tropical Ecology. 2006;47:1–12.

52.

Lopez-Toledo L, Martínez-Ramos M. The soil seed bank in abandoned tropical pastures: the source of regeneration or invasion? Revista Mexicana de Biodiversidad. 2011;82:663–78.

53.

Mack MC, D’Antonio CM. The effects of exotic grasses on litter decomposition in a Hawaiian Woodland: the importance of indirect effects. Ecosystems. 2003;6: 723–38. https://doi.org/10.1007/s10021-003-0119-y.

54.

Madawala HMSP, Ekanayake SK, Perera GAD. Diversity, composition, and richness of soil seed banks in different forest communities at Dotalugala Man and Biosphere Reserve, Sri Lanka. Ceylon J Sci. 2016;45(1):43–55. https://doi.org/10.4038/cjs.v45i1.7363.

55.

Magurran AE. Ecological diversity and its measurement. Cambridge: Cambridge University Press; 1988.

56.

Mahdhi M, Tounekti T, Khemira H. The invasive character of Prosopis juliflora facilitated by its allelopathy and wide mutualistic interaction with soil microorganisms. J Biol Sci. 2018;18:115–23.

57.

Maranon T. Soil seed bank and community dynamics in an annual-dominated Mediterranean salt-marsh. J Vegetation Sci. 1998;9:371–8.

58.

Marcelo S, Mario G, Avi P, Jaime K. Effects of grazing on soil seed bank dynamics: an approach with functional groups. J Vegetation Sci. 2003;14:375–86.

59.

Miranda RQ, Oliveira MTP, Correia RM, Almeida-Cortez JS, Pompelli MF. Germination of Prosopis juliflora (Sw) DC seeds after scarification treatments. Plant Species Biol. 2011;26:186–92.

60.

Moles AT, Hodson DW, Webb CJ. Seed size and shape and persistence in the soil in the New Zealand flora. Oikos. 2000;89:541–5.

61.

Mouissie AM, Lengkeek W, Van Diggelen R. Estimating adhesive seed-dispersal distances: field experiments and correlated random walks. Functional Ecol. 2005;19:478–86. https://doi.org/10.1111/j.1365-2435.2005.00992.x.

62.

Muller-Dombis D, Ellenberg H. Aims and methods of vegetation ecology. New York: John Wiley and Sons; 1974.

63.

Muturi GM, Poorter L, Mohren GMJ, Kigomo BN. Ecological impact of Prosopis species invasion in Turkwel riverine forest, Kenya. J Arid Environ. 2013;92:89–97.

64.

Mworia JK, Kinyamario JI, Omari JK, Wambua JK. Patterns of seed dispersal and establishment of the invader Prosopis juliflora in the upper floodplain of Tana River, Kenya. Af J Range Forage Sci. 2011;28(1):35–41.

65.

Olano JM, Caballero I, Escudero A (2012). Soil seed bank recovery occurs more rapidly than expected in semi-arid Mediterranean gypsum vegetation. Annals of Botany 109: 299–307Doi:https://doi.org/10.1093/aob/mcr260, available online at www.aob.oxfordjournals.org

66.

Pasiecznik, NM, Felker P, Harris PJC, Harsh LN, Cruz G, Tewari JC, Cadoret K, Maldonado LJ (2001). The Prosopis juliflora - Prosopis pallida complex: a monograph, HDRA, Coventry, UK. pp172, ISBN: 0 905343 301.

67.

Peco B, Traba J, Levassor C, Sanchez AM, Azcarate FM. (2003). Seed size, shape, and persistence in dry Mediterranean grass and scrublands. Seed Sci Res. 2003;13:87–95. https://doi.org/10.1079/SSR2002127.

68.

Perera GA. Diversity and dynamics of the soil seed bank in tropical semideciduous forests of Srilanka, Tropical Ecology. 2005;46:65–78.

69.

Qian J, Liu Z, Hatier JHB, Liu B. The vertical distribution of soil seed bank and its restoration implications in an active dune of Northeastern Inner Mongolia, China. Land Degradation Deve. 2016;27:305–15. https://doi.org/10.1002/ldr.2428.

70.

Reubens B, Heyn M, Gebrehiwot K, Hermy M, Muys B. Persistent soil seed banks for natural rehabilitation of dry tropical forests in Northern Ethiopia. Tropicultura. 2007;25(4):204–14.

71.

Robert DC, Edith BA. Composition of soil seed banks in southern California coastal sage scrub and adjacent exotic grassland. Plant Ecol. 2008;198:37–46. https://doi.org/10.1007/s11258-007-9383-9.

72.

Rotich TI. Progressive effects of Prosopis juliflora (S.W.) (DC) on grazing natural pasture and browse plants in Baringo County, Kenya. Kenya: Unpublished MSc Thesis, University of Nairobi; 2016.

73.

Saatkamp A, Pochlod P Lawrence, Venable D. (2014). The functional role of soil seed bank in natural communities. CABI. Seeds: The Ecology of Regeneration in Plant Communities, 3rd Edition (ed. Gallagher, R.S.).

74.

Salazar A (2010). “Seed dynamics and seedling establishment of woody species in the tropical savannas of Central Brazil (Cerrado)”. Open Access Dissertations pp. 371. https://scholarlyrepository.miami.edu/oa_dissertations/371

75.

Sanou L, Zida D, Savadogo P, Thiombiano A (2018). Comparison of aboveground vegetation and soil seed bank composition at sites of different grazing intensity around a savanna woodland watering point in West Africa. Journal of Plant Research https://doi.org/10.1007/s10265-018-1048-3

76.

SAS (2002). SAS/STAT user’s guide, version 9.0, Cary, NC: SAS Institute.

77.

Savadogo P, Sanou L, Dayambam SD, Bognounou F, Thiombiano A. Relationships between soil seed banks and aboveground vegetation along a disturbance gradient in the W National Park trans-boundary biosphere reserve, West Africa. J Plant Ecol. 2016;10(2):349–63. https://doi.org/10.1093/jpe/rtw025.

78.

Shaheen H, Mashwani ZUR, Dar MEUI. Spatial patterns and diversity of alpine vegetation across Langer– Shandur Valley, Hindukush Himalayas. Curr. Sci. 2015;108(8):1534–9.

79.

Shannon CE, Weaver W. The mathematical theory of communication. Urbana: University of Illinois Press; 1949.

80.

Shiferaw H, Teketay D, Nemomissa S. Some biological characteristics that foster the invasion of Prosopis juliflora (Sw.) DC in Middle Awash Rift Valley Area, North-Eastern Ethiopia. J Arid Environ. 2004;58:135–54 www.elsevier.com.

81.

Shiferaw W, Demissew S, Bekele T. Invasive alien plant species in Ethiopia: ecological impacts on biodiversity a review paper. Int J Mol Biol. 2018a;3(4): 171–8. https://doi.org/10.15406/ijmboa.2018.03.00072.

82.

Shiferaw W, Demissew S, Bekele T. “Ecology of soil seed banks: implications for conservation and restoration of natural vegetation”: a review. Int J Biodiversity Conservation. 2018b;10(10):380–93.

83.

Sileshi D, Abraha B (2014). Assessment of soil seed bank composition of woody species in Hgumbirda National Forest Priority Area, Northeastern Ethiopia, Momona Ethiopian Journal of Science (MEJS), 6(1), pp25-44,2014 Mekelle University, ISSN:2220-184X.

84.

Singh G, Rathod TR, Mutha S, Upadhyaya S, Bala N. Impact of Different Tree Species Canopy on Diversity and Productivity of Understory Vegetation in Indian Desert. Tropical Ecology. 2008;49(1):13–23.

85.

Song G, Li X, Hui R (2017) Effect of biological soil crusts on seed germination and growth of an exotic and two native plant species in an arid ecosystem. PLoS ONE, 12(10). Available at: https://doi.org/10.1371/journal.pone.0185839

86.

Sorensen T. A method of establishing groups of equal amplitude in plant sociology based on similarity of species content. Kongelige Danske Videnskabernes Selskab. Biologiske Skrifter. 1948;4:1–34.

87.

Tekle K, Backus I, Skuglund J, Woldu Z. Vegetation on hill slopes of Wello, Ethiopia: degradation and regeneration. Nord Journal of Botany. 1997;17(5): 483–493.

88.

Tesfaye G, Teketay D, Assefa Y, Fetena M. The impact of fire on the soil seed bank regeneration of Harena forest, southeast Ethiopia. Mountain Res Dev. 2004;24:354–61.

89.

The R Core Team (2018). R: a language and environment for statistical computing. In: R Foundation for Statistical Computing (1999-2002), Version 3. 5.1 (2018-07-02).

90.

Tiebel K, Huth F, Wagner S. Soil seed banks of pioneer tree species in European temperate forests: a review. iForest 11: 48-5. 2018. https://doi.org/10.3832/ifor2400-011.

91.

Tsegaye D, Moe RS, Vedeldc P, Aynekulu E. Land-use/cover dynamics in Northern Afar rangelands, Ethiopia. Agriculture, Ecosystems and Environment, 2010; 139:174–180. https://doi.org/10.1016/j.agee.2010.07.017.

92.

Valko O, Torok P, Tothmeresz B, Matus G. Restoration potential in seed banks of acidic fen and dry-mesophilic meadows: can restoration be based on local seed banks? Restoration Ecol. 2011;19:9–15.

93.

Valko O, Tothmeresz B, Kelemen A, Simon E, Miglecz T, Lukacsc BA, Torok P. Environmental factors driving seed bank diversity in alkali grasslands. Agric Ecosystems Environ. 2014;182:80–7 https://doi.org/10.1016/j.agee.2013.06.012.

94.

Wakie T, Paul HE, Jarnevich SC, Laituri M. Mapping current and potential distribution of non-native Prosopis juliflora in the Afar Region of Ethiopia. Plos One. 2014;9(11):e112854 www.plosone.org.

95.

Woldu Z, Feoli E, Nigatu L. Partitioning an Elevation Gradient of Vegetation from Southeastern Ethiopia by Probabilistic Methods. Vegetation. 1989;81:189–198.

96.

Woldu Z, Backeus I. The Shrubland Vegetation in Western Shewa, Ethiopia and Its Possible Recovery. Journal of Vegetation Science. 1991;2:173–180.

97.

Wootton JT. Effects of disturbance on species diversity: a multi-trophic perspective. American Naturalist. 1998;152(6):803–25.

98.

Yirdaw E, Starr M, Negash M, Yimer F. Influence of topographic aspect on floristic diversity, structure and treeline of afromontane cloud forests in the Bale Mountains, Ethiopia. J. For. Res. 2015;26(4):919–931. https://doi.org/10.1007/s11676-015-0155-4.

99.

Zhang C, Dong Q, Chu H, Shi J, Li S, Wang Y, Yang X. Grassland community composition response to grazing intensity under different grazing regimes. Rangeland Ecology & Management; 2017. https://doi.org/10.1016/j.rama.2017.09.007.

100.

Zobel M, Kalamees R, Püssa K, Roosaluste E, Moora M. Soil seed bank and vegetation in mixed coniferous forest stands with different disturbance regimes. Forest Ecol Manag. 2007;250:71–6.

Journal of Ecology and Environment