Abstract
The presence, diversity and abundance of non-native plant species in natural vegetation are common condition indicators used to determine conservation status, with consequences for management strategies and investment. The rationale behind non-native species metrics as condition indicators is the assumption that non-natives have negative consequences on native biodiversity and habitat condition. The case against non-native species is not so clear-cut, with some studies reporting neutral or even facilitative interactions, often depending on spatial scale. Observational and experimental evaluations of the impact of particular non-native species on biodiversity provide a vital evidence-base for general conservation management strategies. Unintentionally though, many studies that quantify the impacts of non-native species have resulted in a publication bias in which species with known impacts are selected for investigation far more often than benign species. Here we argue that meta-analyses of the impacts of individual non-native species on natives, no matter how meticulous or objective, should not be generalized beyond the set of ‘training’ species. The likelihood of such extrapolation is increased when meta-analyses are reported with little qualification as to the skewed sampling towards problematic species, and because alternative findings such as non-native assemblages having positive interactions with native biodiversity, are under-reported. To illustrate, we discuss two meta-analyses that make general conclusions from impact studies skewed towards ‘transformers’, the most extreme invaders. We warn that if generic non-native species management strategies were to be based on these conclusions, they could not only fail to meet objectives but in some instances harm native biodiversity.
Similar content being viewed by others
References
Atwater DZ, Bauer CM, Callaway RM (2011) Indirect positive effects ameliorate strong negative effects of Euphorbia esula on a native plant. Plant Ecol 212:1655–1662
Badgery WB, Kemp DR, Michalk DL, King WM (2005) Competition for nitrogen between Australian native grasses and the introduced weed Nassella trichotoma. Ann Bot 96:799–809
Davis MA, Chew MK, Hobbs RJ, Lugo AE, Ewel JJ et al (2011) Don’t judge species on their origins. Nature 474:153–154
Fridley JD, Stachowicz JJ, Naeem S, Sax DF, Seabloom EW et al (2007) The invasion paradox: reconciling pattern and process in species invasions. Ecology 88:3–17
Gaertner M, Den Breeyen A, Hui C, Richardson DM (2009) Impacts of alien plant invasions on species richness in Mediterranean-type ecosystems: a meta-analysis. Prog Phys Geogr 33:319–338
Gibbons P, Freudenberger D (2006) An overview of methods used to assess vegetation condition at the scale of the site. Ecol Manag Restor 7(s1):S10–S17
Kuebbing E, Nuñez MA (2016) Invasive non-native plants have a greater effect on neighbouring natives than other non-natives. Nat Plants 2:16134
Lambrinos JG (2000) The impact of the invasive alien grass Cortaderia jubata (Lemoine) Stapf on an endangered mediterranean-type shrubland in California. Divers Distrib 6:217–231
Malmstrom CM, Stoner CJ, Brandenburg S, Newton LA (2006) Virus infection and grazing exert counteracting influences on survivorship of native bunchgrass seedlings competing with invasive exotics. J Ecol 94:264–275
Marcantonio M, Rocchini D, Ottaviani G (2014) Impact of alien species on dune systems: a multifaceted approach. Biodivers Conserv 23:2645–2668
Martín-Forés I, Castro I, Acosta-Gallo B, del Pozo A, Sánchez-Jardón L et al (2016) Alien plant species coexist over time with native ones in Chilean Mediterranean grasslands. J Plan Ecol 9:682–691
Martín-Forés I, Guerin GR, Lowe AJ (2017) Weed abundance is positively correlated with native plant diversity in grasslands of southern Australia. PLoS ONE 12:e0178681
Oswalt CM, Oswalt SN, Clatterbuck WK (2007) Effects of Microstegium vimineum (Trin.) A. Camus on native woody species density and diversity in a productive mixed-hardwood forest in Tennessee. For Ecol Manag 242:727–732
Pattison Z, Minderman J, Boon PJ, Willby N (2017) Twenty years of change in riverside vegetation: what role have invasive alien plants played? Appl Veg Sci 20:422–434
Powell KI, Chase JM, Knight TM (2011) A synthesis of plant invasion effects on biodiversity across spatial scales. Am J Bot 98:539–548
Richardson DM, Pyšek P, Rejmánek M, Barbour MG, Panetta FD et al (2000) Naturalization and invasion of alien plants: concepts and definitions. Divers Distrib 6:93–107
Rodríguez LF (2006) Can invasive species facilitate native species? Evidence of how, when, and why these impacts occur. Biol Invasions 8:927–939
Rodríguez-Echeverría S, Afonso C, Correia M, Lorenzo P, Roiloa SR (2013) The effect of soil legacy on competition and invasion by Acacia dealbata Link. Plant Ecol 214:1139–1146
Sax DF (2002) Native and naturalized plant diversity are positively correlated in scrub communities of California and Chile. Divers Distrib 8:193–210
Schlaepfer MA, Sax DF, Olden JD (2011) The potential conservation value of non-native species. Conserv Biol 25:428–437
Turner J (2012) National recovery plan for the iron-grass natural temperate grassland of South Australia ecological community 2012. Department of Environment and Natural Resources, Port Lincoln
Turner PJ, Scott JK, Spafford H (2008) The ecological barriers to the recovery of bridal creeper (Asparagus asparagoides (L.) Druce) infested sites: impacts on vegetation and the potential increase in other exotic species. Austral Ecol 33:713–722
Vilà M, Espinar JL, Hejda M, Hulme PE, Jarošík V et al (2011) Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems. Ecol Lett 14:702–708
Ward-Fear G, Brown GP, Pearson DJ, Shine R (2017) An invasive tree facilitates the persistence of native rodents on an over-grazed floodplain in tropical Australia. Austral Ecol 42:385–393
Witkowski ETF (1991) Effects of invasive alien acacias on nutrient cycling in the coastal lowlands of the Cape fynbos. J Appl Ecol 28:1–15
Zavaleta ES, Hobbs RJ, Mooney HA (2001) Viewing invasive species removal in a whole-ecosystem context. Trends Ecol Evol 16:454–459
Acknowledgements
We thank the Terrestrial Ecosystem Research Network supported by the Australian Government through the National Collaborative Research Infrastructure Strategy.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by David Hawksworth.
This article belongs to the Topical Collection: Invasive species.
Rights and permissions
About this article
Cite this article
Guerin, G.R., Martín-Forés, I., Sparrow, B. et al. The biodiversity impacts of non-native species should not be extrapolated from biased single-species studies. Biodivers Conserv 27, 785–790 (2018). https://doi.org/10.1007/s10531-017-1439-0
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10531-017-1439-0