Tree conifers invasion in steppe areas and Austrocedus chilensis forests in NW Patagonia
Keywords:
invasions, ponderosa pine, Douglas fir, lodgepole pine, cypress forests, PatagoniaAbstract
Commercial forestry is carried out with a reduced set of species, with known silvicultural and industrial managements. Thus, these species are frequently planted far away from their natural habitats and introduced in new environments, creating a risk for starting invasion processes in natural or seminatural systems adjacent to the plantations. In NW Patagonia, commercial forestry with exotic species is recent (< 50 years), and presently only 70000 hectares have been planted of an area estimated to have 2 million hectares suitable for tree planting. The rate of afforestation is increasing in the last decade. The most commonly planted species is Pinus ponderosa Doug (Laws) (ponderosa pine) (80% of planted surface area), followed by Pseudotsuga menziesii (Mirb) Franco (Douglas fir) and Pinus contorta Dougl. (lodgepole pine). In contiguous areas to plantations, seedling recruitment of these species has been already observed irrespectively if they were covered or not by natural vegetation. This work analyses, at a regional scale, the presence and rate of recruitment of seedlings of these introduced species in two natural ecosystems: steppe areas and woodlands dominated by a native conifer Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri (“ciprés de la cordillera”). Our aim was to determine whether these exotic species have initiated an invasion process. Thirty-four plantations that had reached reproductive stage were selected in an area extending from the center of Neuquén Province (39o48’S) to the North of Chubut Province (42o10’S). Natural regeneration, density (no individuals/ ha), distance to plantation, age, height and presence of cones were registered in adjacent areas of seminatural communities. Any symptoms of disturbances (past and current) and vegetation cover (percentage and dominant species) were recorded. In the steppe, lodgepole pine had greater regeneration than ponderosa pine, considering both expansion distance (> 300m vs. 50m) and density (420 vs. 100 indiv/ha). Also, lodgepole seedling recruitment occurred in more sites (63% vs. 36%) and in plantations with younger trees (12 years vs. 18 years). Overall, recruitment of the introduced conifers was greater at steppe sites in which cattle rearing had been reported in the past, typically with a low vegetation cover or where burned. In the native woodland sites, Douglas fir displayed a better capacity to propagate than ponderosa pine. Both species began to produce seedlings at the same age (17-18 years). Nevertheless, distances of recruitment were greater for Douglas fir (140 versus 70 m), as were densities (1500 vs. 250 individuals/ha) and percent sites with recruitment (100% vs. 67%). Open areas and disturbed places (paths, trails or clearings) displayed greater recruitment capacity than undisturbed areas. Indeed, recruitment was absent in sites highly covered and in sites with abundant understorey vegetation. In both studied systems, areas located downwind presented greater recruitment. Results of expansion distance to determine whether these exotic species have initiated an invasion process were compared with distance of advance proposed by Richardson to define invasions. Our results indicate that an incipient invasion of lodgepole pine in steppe and Douglas fir in woodlands dominated by the native conifer is occurring. Lodgepole pine produced seedlings at the earliest age (12 years). Ponderosa pine does not seem to behave like an invader to the studied communities. The information obtained from this study allowed us to identify factors that could facilitate or limit the process of expansion of these species related to propagule pressure, seed predation and disturbances. We propose recommendations on how to follow it and assure that preventive tactics are adopted to reduce the risk for the occurrence of a biological invasion.
References
BEVER, JD. 1994. Feedback between plants and their soil communities in an old field community. Ecology, 75:1965-1977.
BEVER, JD. 2003. Soil community feedback and the coexistence of competitors: conceptual frameworks and empirical tests. New Phytologist, 157:465-473.
BUSTOS, C. 2002. Características del clima en el Sudo-este del departamento Collón-Cura (Neuquén) INTA Bariloche, Comunicación Técnica no 24. Area de recursos naturales Agrometereología.
CACCIA, FD & CL BALLARÉ. 1998. Effects of tree cover, understory vegetation, and litter on regeneration of Douglas-fir (Pseudotsuga menziesii) in southwestern Argentina. Canadian Journal of Forest Research, 28(5):683-692.
CALLAWAY, RM; B MAHALL; C WICKS; J PANKEY & CA ZABINSKI. 2003. Soil fungi and the effects of an invasive forb on grasses: neighbor identity matters. Ecology, 84:129-135.
CHAUCHARD, LM; GA LOGUERCIO & J SENS HOURCADE. 1988. Inventario Forestal. Plantaciones. Area Península Huemul. Parque Nacional Nahuel Huapi. Informe Técnico.
DANIEL, TW; JA HELMS & FS BACKER. 1982. Principios de Silvicultura. Ed. McGraw-HILL. México.
DAVIS, AD; DJP GRIME & K THOMPSON. 2000. Fluctuating resources in plant communities: a general theory of invasibility. Journal of Ecology, 88:528-534.
ELTON, CS. 1958. The Ecology of Invasions by Animals and Plants. Methuen. London, UK.
Ewel, JJ; DJ O’Dowd; J Bergelson; CC Daehler; CM D ́Antonio et al. 1999. Deliberate Introductions of Species: Research Needs – Benefits can be reaped, but risks are high. BioScience, 49(8):619-630.
HARPER, JL. 1977. Population Biology of Plants. Academic Press. London, UK.
HERMAN, RK & DP LAVENDER. 1990. Pseudotsuga menziesii (Mirb.) Franco. Douglas-Fir in: Silvics of North America. Volume 1. Conifers. Agriculture Handbook 654 USDA.
HEYWOOD, VH. 1989. Patterns, extents and modes of invasions by terrestrial plants. Pp. 31-60 in: JA Drake; HA Mooney; F di Castri; RH Groves; FJ Kruger; M Rejmanek & M Williamson (eds.). Biological invasions: a global perspective. John Wiley. Chichester, UK.
HOBBS, RJ & HA MOONEY. 1986. Community changes following shrub invasion of grassland. Oecología, 70:508-513.
HODKINSON DJ; AP ASKEW; K THOMPSON; JG HODGSON; JP BAKKER ET AL. 1998. Ecological correlates of seed size in the British flora. Funct. Ecol. 12:762-766.
JANZEN, DH. 1969. Seed eaters versus seed size, number, toxicity and dispersal. Evolution, 23:1-27.
KOHM, KA & JF FRANKLIN. 1997. Creating a Forestry for the 21st Century. The Science of Ecosystem Management. Island Press. Washington, USA.
LANNER, RM. 1998. Seed dispersal in Pinus. Pp. 281- 295 in: DM Richardson (Ed.). Ecology and Biogeography of Pinus. Cambridge University Press. Cambridge, UK.
LEDGARD, N. 2001. The spread of lodgepole pine (Pinus contorta, Dougl.) in New Zealand. Forest Ecol. and Manag., 141:43-57.
LONSDALE, WM. 1999. Global patterns of plant invasions and the concept of invasibility. Ecology, 80:1522-1536.
MACARTHUR, RH. 1972. Geographical ecology. Harper & Row. New York, USA.
MACK, RN; D SIMBERLOFF; WM LONSDALE; H EVANS; M CLOUT ET AL. 2000. Biotic invasions: causes, epidemiology, global consequences, and control. Ecological Applications, 10(3):689-710.
MATTHEWS, JW & K CLAY. 2001. Influence of fungal endophyte infection on plant/soil feedback and community interactions. Ecology, 82:500-509.
MAY, RM. 1973. Stability and Complexity in Model Ecosystems. Princeton University Press. Princeton, N.J. USA.
MOODY, ME & RN MACK. 1988. Controlling the spread of plant invasions: The importance of nascent foci. J. of Appl. Ecolog., 25:1009-1021.
PACKER, A & K CLAY. 2000. Soil pathogens and spatial patterns of seedling mortality in a temperate tree. Nature, 404:278-281.
PARUELO, JM; A BELTRÁN; E JOBBÁGY; OE SALA & R GOLLUSCIO. 1998. The climate of Patagonia: general patterns and controls on biotic processes. Ecol. Aust., 8:85-101.
REJMÁNEK, M & D RICHARDSON. 1996. What attributes make some plant species more invasive? Ecology, 77(6):1655-1661.
REJMÁNEK, M. 2000. Invasive plants, approaches and predictions. Austral ecology, 5:497-506.
RICHARDSON, DM & W BOND. 1991. Determinants of plant distribution: Evidence from pine invasions. The American Naturalist, 137(5):639-668.
RICHARDSON DM. 1999. Commercial forestry and agroforestry as sources of invasive alien trees and shrubs. 16. Pp. 237-257 in: OT Sandlund; PJ Schei & A Viken. (eds.). Invasive species and Biodiversity Management. Kluwer Academic Publishers.
RICHARDSON, DM & SI HIGGINS. 1998. Pines as invaders in the southern hemisphere. Pp. 450- 473 in: DM Richardson (ed.). Ecology and Biogeography of Pinus. Cambridge University Press. Cambridge, UK.
RICHARDSON, DM; P PYSEK; M REJMÁNEK; MG BARBOUR; FD PANETTA ET AL. 2000. Naturalization and invasion of alien plants: concepts and definitions. Diversity & Distributions, 6:93-107.
SARUKHÁN J & JL HARPER. 1973. Studies on plant demography: Ranunculus repens L., R. bulbosus L. and R.acris. I. Population flux and survivorship. J. Ecol., 61:675-716.
SCHLICHTER TM & P LACLAU. 1998. Ecotono estepa-bosque y plantaciones forestales en la Patagonia norte. Ecol. Aust., 8:285-296.
SCHMIDT WC & RR ALEXANDER. 1985. Strategies for managing lodgepole pine. In: Baumgartner et al. (eds.) Lodgepole pine: The Species and its Management. Proceedings of the Symposium, Vancouver, Canada. Available from Washington State University. Pullman, WA, USA.
SECRETARÍA DE AGRICULTURA, GANADERÍA, PESCA Y ALIMENTACIÓN. 1999. Argentina, oportunidades de Inversión en Bosques Cultivados. SAGPyA. 208 págs.
SIMBERLOFF, D; MA RELVA & M NUÑEZ. 2002. Gringos en el bosque: Introduced tree invasion in a native Nothofagus/Austrocedrus forest. Biological Invasions, 4:35-53.
THOMPSON, K; SR BAND & JG HODGSON. 1993. Seed size and shape predict persistence in soil. Funct. Ecol., 7:236-241.
THOMPSON, K; JP BAKKER & RM BEKKER. 1998. Ecological correlates of seed persistence in the soil in the north-west European flora. J. Ecol., 86:163-170.
THOMPSON, K; RM BEKKER & JP BAKKER. 1997. The Soil Seed Banks of Northwest Europe: Methodology, Density and Longevity. Cambridge University Press. Cambridge, UK.
TILMAN, D; J KNOPS; D WEDIN; P REICH; M RITCHIE ET AL. 1997. The influence of functional diversity and composition on ecosystem processes. Science, 277:1300-1302.
VENABLE DL & JS BROWN. 1988. The selective interactions of dispersal, dormancy and seed size as adaptations for reducing risk in variable environments. Am. Nat., 131:360-384.
VITOUSEK, PM; LR WALKER; LD WHITEAKER; D MUELLER-DOMBOIS & PA MATSON. 1987. Biological invasion by Mirica faya alters ecosystem development in Hawaii. Science, 238:802-804.
WALKER, S; JB WILSON & WG LEE. 2005. Does fluctuating resource availability increase invasibility? Evidence from field experiments in New Zealand short tussock grassland. Biological Invasions, 7:195-211.
WILLIAMSON, M. 1996. Biological invasions. Chapman & Hall. London, UK.
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