Research Articles |
|
|
|
|
Species-specific traits determine shrub-annual interactions during a growing season |
GeFei ZHANG, WenZhi ZHAO* |
Linze Inland River Basin Research Station, Key Laboratory of Ecohydrology of Inland River Basin, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China |
|
|
Abstract Stress gradient hypothesis predicted that facilitative interactions usually increase in intensity and are importance with abiotic stress. By contrast, facilitation may be lost in time, when it involves the growth of benefactors or beneficiaries. Less is known about which response pattern is more common in arid desert. We present an empirical study to explore shrub-annual interactions at the community and individual level along the course of a single growing season in a desert steppe in northwest China. Here the severity of drought stress may increase in time due to uneven precipitation during plant growing season. We assessed growth responses of annuals in understory where two dominant shrubs were removed. Annuals responses showed a switch from weakly positive to more strongly positive beneath Calligonum mongolicum, whereas from positive to negative beneath Nitraria sphaerocarpa during the growing season. Additionally, annual species with contrasting functional traits showed distinct growth responses to canopies removal. There was evidence of an increase in soil moisture below the canopy of shrubs, but a decrease in potential evaporation rate and photosynthetically active radiation, which can partly explain these species-specific responses. We conclude that the balance between competitive and facilitative effects in shrub-annual interactions is not only governed by the severity of stress but also determined by plant traits, such as canopy structure of shrubs and functional traits of their understory annuals.
|
Received: 16 May 2014
Published: 05 February 2015
|
Fund: This work was financial supported by the National Basic Re-search Program of China (2013CB429903) and the National Natural Science Foundation of China (41301603). |
Corresponding Authors:
|
|
|
Armas C, Ordiales R, Pugnaire F I. 2004. Measuring plant interactions: a new comparative index. Ecology, 85(10): 2682–2686.Armas C, Pugnaire F I. 2005. Plant interactions govern population dynamics in a semi-arid plant community. Journal of Ecology, 93(5): 978–989.Armas C, Pugnaire F I. 2009. Ontogenetic shifts in interactions of two dominant shrub species in a semi-arid coastal sand dune system. Journal of Vegetation Science, 20(3): 535–546.Armas C, Kim J, Bleby T, et al. 2012. The effect of hydraulic lift on organic matter decomposition, soil nitrogen cycling, and nitrogen acquisition by a grass species. Oecologia, 168(1): 11–22.Bertness M, Ewanchuk P. 2002. Latitudinal and climate-driven variation in the strength and nature of biological interactions in New England salt marshes. Oecologia, 132(3): 392–401.Brooker R W, Kikvidze Z, Pugnaire F I, et al. 2005. The importance of importance. Oikos, 109(1): 63–70.Brooker R W, Maestre F T, Callaway R M, et al. 2008. Facilitation in plant communities: the past, the present, and the future. Journal of Ecology, 96(1): 18–34.Bruno J F, Stachowicz J J, Bertness M D. 2003. Inclusion of facilitation into ecological theory. Trends in Ecology and Evolution, 18(3): 119–125.Bulleri F, Xiao S, Maggi E, et al. 2014. Intensity and temporal variability as components of stress gradients: implications for the balance between competition and facilitation. Oikos, 123(1): 47–55.Callaway R, Brooker R W, Choler P, et al. 2002. Positive interactions among alpine plants increase with stress. Nature, 417(6891): 844–848.Callaway R, Kikodze D, Chiboshvili M, et al. 2005. Unpalatable plants protect neighbors from grazing and increase plant community diversity. Ecology, 86(7): 1856–1862.Callaway R. 2007. Positive Interactions and Interdependence in Plant Communities. Netherlands: Springer, 179–254.Cavieres L, Badano E, Sierra-Almeida A, et al. 2006. Positive interactions between alpine plant species and the nurse cushion plant Laretia acaulis do not increase with elevation in the Andes of central Chile. New Phytologist, 169(1): 59–69.Choler P, Michalet R, Callaway R. 2001. Facilitation and competition on gradients in alpine plant communities. Ecology, 82(12): 3295–3308.Chu C J, Weiner J, Maestre F T, et al. 2009. Positive interactions can increase size inequality in plant populations. Journal of Ecology, 97(6): 1401–1407.Dohn J, Dembélé F, Karembé M, et al. 2013. Tree effects on grass growth in savannas: competition, facilitation and the stress-gradient hypothesis. Journal of Ecology, 101(1): 202–209.Good M K, Clarke P J, Price J N, et al. 2014. Seasonality and facilitation drive tree establishment in a semi-arid floodplain savanna. Oecologia, 175(1): 261–271.Gómez-Aparicio L, Zamora R, Gómez J M, et al. 2004. Applying plant facilitation to forest restoration: A meta-analysis of the use of shrubs as nurse plants. Ecological Applications, 14(4): 1128–1138.Hautier Y, Niklaus P A, Hector A. 2009. Competition for light causes plant biodiversity loss after eutrophication. Science, 324(5927): 636–638.He Q, Cui B S, An Y. 2011. The importance of facilitation in the zonation of shrubs along a coastal salinity gradient. Journal of Vegetation Science, 22(5): 828–836.He Q, Cui B S, Bertness M D, et al. 2012. Testing the importance of plant strategies on facilitation using congeners in a coastal community. Ecology, 93(9): 2023–2029.He Q, Bertness M D. 2014. Extreme stresses, niches and positive species interactions along stress gradients. Ecology, 95(6):1437–1443.Holmgren M, Gómez-Aparicio L, Quero J, et al. 2012. Non-linear effects of drought under shade: reconciling physiological and ecological models in plant communities. Oecologia, 169(2): 293–305.Holzapfel C, Mahall B E. 1999. Bidirectional facilitation and interference between shrubs and annuals in the Mojave Desert. Ecology, 80(5): 1747–1761.Kidron G J, Gutschick V P. 2013. Soil moisture correlates with shrub-grass association in the Chihuahuan Desert. Catena, 107: 71–79.Kikvidze Z, KhetsurianiL, Kikodze D, et al. 2006. Seasonal shifts in competition and facilitation in subalpine plant communities of the central Caucasus. Journal of Vegetation Science, 17(1): 77–82.Kikvidze Z, Callaway R M. 2009. Ecological facilitation may drive major evolutionary transitions. BioScience, 59(5): 399–404.Kikvidze Z, Suzuki M, Brooker R. 2011. Importance versus intensity of ecological effects: why context matters. Trends in Ecology and Evolution, 26(8): 383–388.Koyama A, Tsuyuzaki S. 2013. Facilitation by tussock-forming species on seedling establishment collapses in an extreme drought year in a post-mined Sphagnum peatland. Journal of Vegetation Science, 24(3): 473–483.Li J, Zhao C Y, Song Y J, et al. 2010. Spatial patterns of desert annuals in relation to shrub effects on soil moisture. Journal of Vegetation Science, 21(2): 221–232.Ludwig F, Dawson T E, Prins H H T, et al. 2004. Below-ground competition between trees and grasses may overwhelm the facilitative effects of hydraulic lift. Ecology Letters, 7(8): 623–631.Maestre F T, Bautista S, Cortina J. 2003. Positive, negative, and net effects in grass-shrub interactions in Mediterranean semiarid grasslands. Ecology, 84(12): 3186–3197.Maestre F T, Cortina J. 2004. Do positive interactions increase with abiotic stress? A test from a semi-arid steppe. Proceedings of the Royal Society of London. Series B: Biological Sciences, 271(Suppl. 5): S331–S333.Maestre F T, Escolar C, Martínez I, et al. 2008. Are soil lichen communities structured by biotic interactions? A null model analysis. Journal of Vegetation Science, 19(2): 261–266.Maestre F T, Callaway R M, Valladares F, et al. 2009. Refining the stress-gradient hypothesis for competition and facilitation in plant communities. Journal of Ecology, 97(2): 199–205.Mauchamp A, Janeau J L. 1993. Water funnelling by the crown of Flourensia cernua, a Chihuahuan Desert shrub. Journal of Arid Environments, 25(3): 299–306.Michalet R. 2006. Is facilitation in arid environments the result of direct or complex interactions? New Phytologist, 169(1): 3–6.Miriti M N. 2006. Ontogenetic shift from facilitation to competition in a desert shrub. Journal of Ecology, 94(5): 973–979.Moro M J, Pugnaire F I, Haase P, et al. 1997. Effect of the canopy of Retama sphaerocarpa on its understorey in a semiarid environment. Functional Ecology, 11(4): 425–431.Pennings S C, Grant M B, Bertness M D. 2005. Plant zonation in low-latitude salt marshes: disentangling the roles of flooding, salinity and competition. Journal of Ecology, 93(1): 159–167.Poulos J M, Rayburn A P, Schupp E W. 2014. Simultaneous, independent, and additive effects of shrub facilitation and understory competition on the survival of a native forb (Penstemon palmeri). Plant Ecology, 215(4): 517–426.Reisman-Berman O. 2007. Age-related change in canopy traits shifts conspecific facilitation to interference in a semi-arid shrubland. Ecography, 30(4): 459–470.Roux P, McGeoch M. 2010. Interaction intensity and importance along two stress gradients: adding shape to the stress-gradient hypothesis. Oecologia, 162(3): 733–745.Schramm J, Ehrenfeld J. 2010. Leaf litter and understory canopy shade limit the establishment, growth and reproduction of Microstegium vimineum. Biological Invasions, 12(9): 3195–3204.Shiponeni N N, Carrick P J, Allsopp N, et al. 2014. Effects of root competition and soils on seedling establishment at the ecotone between an arid grassland and succulent shrubland in South Africa. Journal of Vegetation Science, 25(2): 402–410.Soliveres S, DeSoto L, Maestre F T, et al. 2010. Spatio-temporal heterogeneity in abiotic factors modulate multiple ontogenetic shifts between competition and facilitation. Perspectives in Plant Ecology and Evolution Systematics, 12(3): 227–234.Sthultz C M, Gehring C A, Whitham T G. 2007. Shifts from competition to facilitation between a foundation tree and a pioneer shrub across spatial and temporal scales in a semiarid woodland. New Phytologist, 173(1): 135–145.Valladares F, Niinemets Ü. 2008. Shade tolerance, a key plant feature of complex nature and consequences. Annual Review of Ecology, Evolution, and Systematics, 39(1): 237–257.Veblen K E. 2008. Season- and herbivore-dependent competition and facilitation in a semiarid savanna. Ecology, 89(6): 1532–1540.Weedon J T, Facelli J M. 2008. Desert shrubs have negative or neutral effects on annuals at two levels of water availability in arid lands of South Australia. Journal of Ecology, 96(6): 1230–1237.Zhao W Z, Hu G L, Zhang Z H, et al. 2008. Shielding effect of oasis-protection systems composed of various forms of wind break on sand fixation in an arid region: A case study in the Hexi Corridor, northwest China. Ecological Engineering, 33(2): 119–125.Zhao W Z, Liu B. 2010. The response of sap flow in shrubs to rainfall pulses in the desert region of China. Agricultural and Forest Meteorology, 150(9): 1297–1306. |
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
|
Shared |
|
|
|
|
|
Discussed |
|
|
|
|