Abstract
Plant communities are structured by both competition and facilitation. The interplay between the two interactions can vary depending on environmental factors, nature of stress, and plant traits. However, whether positive or negative interactions dominate in regions of high biotic and abiotic stress remains unclear. We studied herbaceous plant communities associated with a dwarf shrub Caragana versicolor in semi-arid, high altitude Trans-Himalayan rangelands of Spiti, India. We surveyed 120 pairs of plots (within and outside shrub canopies) across four watersheds differing in altitude, aspect, and dominant herbivores. Herbaceous communities within shrub canopies had 25% higher species richness, but similar abundance when compared to communities outside the canopy, with the shrub edge having higher diversity than the centre of the canopy. Grasses and erect forbs showed positive associations with the shrub, while prostrate plants occurred at much lower abundance within the canopy. Rare species showed stronger positive associations with Caragana than abundant species. Experimental removal of herbaceous vegetation from within shrub canopies led to 42% increase in flowering in Caragana, indicating a cost to the host shrubs. Our study indicates a robust pattern of a dwarf shrub facilitating local community diversity across this alpine landscape, increasing diversity at the plot level, facilitating rare species, and yet incurring a cost to hosts from the presence of herbaceous plants. Given these large influences of this shrub on the vegetation of these high altitude rangelands, we suggest that the shrub microhabitat be explicitly considered in any analyses of ecosystem health in such rangelands.
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References
Armas C, Pugnaire FI (2005) Plant interactions govern population dynamics in a semi-arid plant community. J Ecol 93:978–989
Armas C, Ordiales R, Pugnaire FI (2004) Measuring plant interactions: a new comparative index. Ecology 85:2682–2686
Badano EI, Cavieres LA (2006) Impacts of ecosystem engineers on community attributes: effects of cushion plants at different elevations of the Chilean Andes. Divers Distrib 12:388–396
Badano EI, Jones CG, Cavieres LA, Wright JP (2006) Assessing impacts of ecosystem engineers on community organization: a general approach illustrated by effects of a high-Andean cushion plant. Oikos 115(2):369–385
Bagchi S, Ritchie ME (2010) Herbivore effects on above- and belowground plant production and soil nitrogen availability in the Trans-Himalayan shrub-steppes. Oecologia 164:1075–1082
Bagchi S, Ritchie ME (2011) Herbivory and plant tolerance: experimental tests of alternative hypotheses involving non-substitutable resources. Oikos 120:119–127
Bertness MD, Callaway R (1994) Positive interactions in communities. TREE 9:191–193
Brooker RW, Maestre FT, Callaway RM, Lortie CL, Cavieres LA, Kunstler G, Liancourt P, Tielbörger K, Travis JM, Anthelme F et al (2008) Facilitation in plant communities: the past, the present, and the future. J Ecol 96:18–34
Callaway RM (2007) Positive interactions and interdependence in plant communities. Springer, Dordrecht
Callaway RM, Brooker RW, Choler P, Kikvidze Z, Lortie CJ, Michalet R, Paolini L, Pugnaire FI, Newingham B, Aschehoug ET et al (2002) Positive interactions among alpine plants increase with stress. Nature 417:844–848
Cavieres LA, Badano EI (2009) Do facilitative interactions increase species richness at the entire community level? J Ecol 97:1181–1191
Cavieres LA, Brooker RW, Butterfield BJ, Cook BJ, Kikvidze Z, Lortie CJ, Michalet R, Pugnaire FI, Schöb C, Xiao S et al (2014) Facilitative plant interactions and climate simultaneously drive alpine plant diversity. Ecol Lett 17:193–202
Facelli JM, Temby AM (2002) Multiple effects of shrubs on annual plant communities in arid lands of South Australia. Aust Ecol 27:422–432
Filazzola A, Lortie CJ (2014) A systematic review and conceptual framework for the mechanistic pathways of nurse plants. Glob Ecol Biogeogr 23:1335–1345
García MC, Bader MY, Cavieres LA (2016) Facilitation consequences for reproduction of the benefactor cushion plant Laretia acaulis along an elevational gradient: costs or benefits? Oikos 125:434–442
Giladi I, Segoli M, Ungar ED (2013) Shrubs and herbaceous seed flow in a semi-arid landscape: dual functioning of shrubs as trap and barrier. J Ecol 101:97–106
Gotelli NJ (2000) Null model analysis of species co-occurrence patterns. Ecology 81(9):2606–2621
Gotelli NJ, Colwell RK (2001) Quantifying biodiversity: procedures and pitfalls in the measurement and comparison of species richness. Ecol Lett 4:379–391
Grabherr G (1980) Variability and ecology of the alpine dwarf shrub community Loiseleurio-Cetrarietum. Vegetatio 41:111–120
Gross K (2008) Positive interactions among competitors can produce species-rich communities. Ecol Lett 11:929–936. doi:10.1111/j.1461-0248.2008.01204.x
Holzapfel C, Mahall BE (1999) Bidirectional facilitation and interference between shrubs and annuals in the Mojave desert. Ecology 80:1747–1761
Hudson BD (1994) Soil organic matter and available water capacity. J Soil Water Conserv 49:189–194
Huston M (1979) A general hypothesis of species diversity. Am Nat 113:81–101
Kondo J, Hirobe M, Yamada Y, Undarmaa J, Sakamoto K, Yoshikawa K (2010) Effects of Caragana microphylla patch and its canopy size on “islands of fertility” in a Mongolian grassland ecosystem. Landsc Ecol Eng. doi:10.1007/s11355-010-0133-0
Koyama A, Sasaki T, Jamsran U, Okuro T (2015) Shrub cover regulates population dynamics of herbaceous plants at individual shrub scale on the Mongolian steppe. J Veg Sci 26(3):441–451
Kumar A, Adhikari BS, Rawat GS (2016) Caragana versicolor Benth. (Fabaceae), a keystone species of high conservation concern in the Hindu Kush Himalayan region. Curr Sci 111(6):985–987
Li P-X, Krüsi BO, Li S-L, Cai X-H, Yu F-H (2011) Facilitation associated with three contrasting shrub species in heavily grazed pastures on the eastern Tibetan Plateau. Commun Ecol 12:1–8
Maestre FT, Callaway RM, Valladares F, Lortie CJ (2009) Refining the stress-gradient hypothesis for competition and facilitation in plant communities. J Ecol 97:199–205
McIntire EJ, Fajardo A (2014) Facilitation as a ubiquitous driver of biodiversity. New Phytol 201(2):403–416
Michalet R, Brooker RW, Cavieres LA, Kikvidze Z, Lortie CJ, Pugnaire FI, Valiente-Banuet A, Callaway RM (2006) Do biotic interactions shape both sides of the humped-back model of species richness in plant communities? Ecol Lett 9:767–773
Michalet R, Xiao S, Touzard B, Smith DS, Cavieres LA, Callaway RM, Whitham TG (2011) Phenotypic variation in nurse traits and community feedbacks define an alpine community. Ecol Lett 14:433–443
Mishra C (2001) High altitude survival: conflicts between pastoralism and wildlife in the Trans-Himalaya. Dissertation. Wageningen University
Mishra C, Van Wieren SE, Ketner P, Heitkönig I, Prins HH (2004) Competition between domestic livestock and wild bharal Pseudois nayaur in the Indian Trans-Himalaya. J Appl Ecol 41:344–354
Oksanen J, Blanchet FG, Friendly M, Kindt R, Legendre P, McGlinn D, Minchin PR, O’Hara RB, Simpson GL, Solymos P, Stevens MHH, Szoecs E, Wagner H (2016) Vegan: community ecology package. R package version 2.4-0. https://CRAN.R-project.org/package=vegan
Osem Y, Perevolotsky A, Kigel J (2007) Interactive effects of grazing and shrubs on the annual plant community in semi-arid Mediterranean shrublands. J Veg Sci 18:869–878
Pescador DS, Chacón-Labella J, de la Cruz M, Escudero A (2014) Maintaining distances with the engineer: patterns of coexistence in plant communities beyond the patch-bare dichotomy. New Phytol 204:140–148. doi:10.1111/nph.12899
Polunin O, Stainton A (1984) Flowers of the himalaya. Oxford, Delhi
Pugnaire FI, Armas C, Maestre FT (2011) Positive plant interactions in the Iberian Southeast: mechanisms, environmental gradients, and ecosystem function. J Arid Environ 75(12):1310–1320
R Core Team (2015) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/
Rebollo S, Milchunas DG, Noy-Meir I, Chapman PL (2002) The role of a spiny plant refuge in structuring grazed shortgrass steppe plant communities. Oikos 98:53–64
Schöb C, Armas C, Pugnaire FI (2013) Direct and indirect interactions co-determine species composition in nurse plant systems. Oikos 122:1371–1379. doi:10.1111/j.1600-0706.2013.00390.x
Schöb C, Prieto I, Armas C, Pugnaire FI (2014a) Consequences of facilitation: one plant’s benefit is another plant’s cost. Funct Ecol 28:500–508
Schöb C, Michalet R, Cavieres LA, Pugnaire FI, Brooker RW, Butterfield BJ, Cook BJ, Kikvidze Z, Lortie CJ, Xiao S, Al Hayek P, Anthelme F, Cranston BH, García M-C, le Bagousse-Pinguet Y, Reid A, le Roux PC, Lingua E, Nyakatya MJ, Touzard B, Zhao L, Callaway RM (2014b) A global analysis of bidirectional interactions in alpine plant communities shows facilitators experiencing strong reciprocal fitness costs. New Phytol 202:95–105
Segoli M, Ungar ED, Giladi I, Arnon A, Shachak M (2012) Untangling the positive and negative effects of shrubs on herbaceous vegetation in drylands. Landsc Ecol 27:899–910
Sherman R, Mullen R, Haomin L, Zhendong F, Yi W (2008) Spatial patterns of plant diversity and communities in Alpine ecosystems of the Hengduan Mountains, northwest Yunnan, China. J Plant Ecol 1:117–136
Smit C, Vandenberghe C, Ouden J, Müller-Schärer H (2007) Nurse plants, tree saplings and grazing pressure: changes in facilitation along a biotic environmental gradient. Oecologia 152:265–273
Soliveres S, Maestre FT (2014) Plant–plant interactions, environmental gradients and plant diversity: a global synthesis of community-level studies. Perspect Plant Ecol Evol Syst 16:154–163
Soliveres S, Eldridge DJ, Maestre FT, Bowker MA, Tighe M, Escudero A (2011) Microhabitat amelioration and reduced competition among understorey plants as drivers of facilitation across environmental gradients: towards a unifying framework. Perspect Plant Ecol Evol Syst 13(4):247–258
Soliveres S, Maestre FT, Berdugo M, Allan E (2015) A missing link between facilitation and plant species coexistence: nurses benefit generally rare species more than common ones. J Ecol 103:1183–1189
Wickham H (2009) ggplot2: elegant graphics for data analysis. Springer, New York
Wright JP, Jones CG (2004) Predicting effects of ecosystem engineers on patch-scale species richness from primary productivity. Ecology 85:2071–2081
Yoshihara Y, Sasaki T, Okuro T, Undarmaa J, Takeuchi K (2010) Cross-spatial-scale patterns in the facilitative effect of shrubs and potential for restoration of desert steppe. Ecol Eng 36:1719–1724
Acknowledgements
We thank Himachal Pradesh Forest Department for permits and their support. Fieldwork was carried out by SBI and Tenzin Sharaf, with assistance from Tandup Chhering, Rinchen Tobge, and many others in Kibber. We thank Dr. Jayashree Ratnam for inputs in the analysis and planning. We are grateful for helpful critiques from the editor and two anonymous reviewers. SBI was supported through the Kishore Vaigyanik Protsahan Yojana fellowship from the Department of Science and Technology, Government of India at IISER, Pune and NCBS Bangalore. SB acknowledges support from DST-SERB, DBT-IISc, and MoEFCC. MS acknowledges support from NCBS.
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Communicated by Bradley J. Butterfield.
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Iyengar, S.B., Bagchi, S., Barua, D. et al. A dominant dwarf shrub increases diversity of herbaceous plant communities in a Trans-Himalayan rangeland. Plant Ecol 218, 843–854 (2017). https://doi.org/10.1007/s11258-017-0734-x
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DOI: https://doi.org/10.1007/s11258-017-0734-x