Abstract
Sexes of dioecious species may have dimorphic responses to environmental variation due to differences in resource requirements and reproductive costs. We analyzed the effect of aridity/relative shrub cover, and vicinity to shrub patches on morpho-chemical traits of sexes of the dioecious perennial grass Poa ligularis in patchy arid ecosystems in northern-central Patagonia. We hypothesized that sexes of P. ligularis have dimorphic responses in morpho-chemical traits in relation to the environmental variation induced by aridity/relative shrub cover and vicinity to shrub patches. We selected seven sites across a gradient of increasing aridity and relative shrub cover. We randomly collected 5–10 P. ligularis plants per site registering the sex (female or male) and location with respect to shrub patches (shrub patch or inter-patch). For each plant, we assessed morpho-chemical traits (height of the vegetative tillers, length/dry weight/area of blades, specific blade area, nitrogen and soluble phenol concentration in blades). Sexes showed dimorphic responses in height of vegetative tillers, blade length, and blade area with respect to vicinity to shrub patches; and in variation of soluble phenolics in blades in relation to aridity/relative shrub cover. Responses in both sexes were opposite to those expected by aridity, highlighting the role of favorable environments induced by shrub canopies on dimorphic responses of sexes of P. ligularis. Resource-rich microsites associated with shrub canopies promoted increased plant performance of females with high reproductive costs while resource-poor open areas, favorable for pollen dispersal, induced improved chemical defenses of males. These results are consistent with the resource availability hypothesis.
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Adler PB, Milchunas DG, Lahuenroth WK, Sala OE, Burke IC (2004) Functional traits of graminoids in semi-arid steppes: a test of grazing histories. J Appl Ecol 41:653–663
Agren J, Danell K, Elmqvist T, Ericson L, Hjälten J (1999) Sexual dimorphism and biotic interactions. In: Geber MA, Dawson TE, Delph LF (eds) Gender and sexual dimorphism in flowering plants. Springer, Berlin, pp 217–246
Aguiar MR, Sala OE (1999) Patch structure, dynamics and implications for the functioning of arid ecosystems. Trends Ecol Evol 14:273–277
Ares JO, Beeskow AM, Bertiller MB, Rostagno CM, Irisarri M, Anchorena J, Defossé G, Merino C (1990) Structural and dynamic characteristics of overgrazed lands of northern Patagonia, Argentina. In: Breymeyer A (ed) Managed grasslands. Elsevier Science, The Netherlands, pp 149–175
Baldi R, Pelliza-Sbriller A, Elston D, Albon S (2004) High potential for competition between guanacos and sheep in Patagonia. J Wildlife Manag 68:924–938
Bertiller MB, Ares JO (2008) Sheep spatial grazing strategies at the arid Patagonian Monte, Argentina. Rang Ecol Manag 61:38–47
Bertiller MB, Ares JO, Graff P, Baldi R (2000) Sex-related spatial patterns of Poa ligularis in relation to shrub patch occurrence in northen Patagonia. J Veg Sci 11:9–14
Bertiller MB, Sain CL, Bisigato AJ, Coronato FR, Ares JO, Graff P (2002) Spatial sex segregation in the dioecious grass Poa ligularis in northern Patagonia: the role of environmental patchiness. Biodivers Conserv 11:69–84
Bertiller MB, Mazzarino MJ, Carrera AL, Diehl P, Satti P, Gobbi M, Sain CL (2006) Leaf strategies and soil N across a regional humidity gradient in Patagonia. Oecologia 148:612–624
Bierzychudek P, Eckhart V (1988) Spatial segregation of the sexes of dioecious plants. Am Nat 132:34–43
Bisigato AJ, Bertiller MB (1997) Grazing effects on patchy dryland vegetation in northern Patagonia. J Arid Environ 36:639–653
Burke IC, Lauenroth WK, Riggle R, Brannen P, Medigan B, Beard S (1999) Spatial variability of soil properties in the shortgrass steppe: the relative importance of topography, grazing, microsite, and plant species in controlling spatial patterns. Ecosystems 2:422–438
Busso CA, Bonvissuto GL, Torres YA (2012) Seedling recruitment and survival off two desert grasses in the Monte of Argentina. Land Degrad Dev 23:116–129
Carrera AL, Bertiller MB (2010) Relationship among plant litter, fine roots, and soil organic C and N across an aridity gradient in northern Patagonia, Argentina. Ecoscience 17:276–286
Cipollini ML, Whigham DF (1994) Sexual dimorphism cost of reproduction in the dioecious shrub Lindera benzoin (Lauraceae). Am J Bot 81:65–75
Coley PD, Bryant JP, Chapin SF III (1985) Resource availability and plant anti-herbivore defense. Science 230:895–899
Cornelissen JHC, Lavorel S, Garnier E, Diaz S, Buchmann N, Gurvich DE, Reich PB, ter Steege H, Morgan HD, van der Heijden MGA, Pausas JG, Poorter H (2003) A handbook of protocols for standardised and easy measurement of plant functional traits worldwide. Aust J Bot 51:335–380
Correa MN (1978) Flora patagónica, parte I. Colección Científica, Instituto Nacional de Tecnología Agropecuaria (INTA), Buenos Aires (in Spanish)
Dawson TE, Ehleringer JR (1993) Gender-specific physiology, carbon isotope discrimination and habitat distribution in boxelder, Acer negundo. Ecology 74:798–815
Dawson TE, Geber MA (1999) Sexual dimorphism in physiology and morphology. In: Geber MA, Dawson TE, Delph LF (eds) Gender and sexual dimorphism in flowering plants. Springer, Heidelberg, pp 175–215
Delph LF (1999) Sexual dimorphism in life history. In: Geber MA, Dawson TE, Delph LF (eds) Gender and sexual dimorphism in flowering plants. Springer, Heidelberg, pp 149–173
Eppley SM (2005) Spatial segregation of the sexes and nutrient effects reproductive success in a dioecious grass. Oecologia 146:549–554
Eppley SM, Stanton ML, Grosberg RK (1998) Intrapopulation sex ratio variation in the salt grass Distichlis spicata. Am Nat 152:659–670
Erickson HE, Soto P, Johnson DW, Roath B, Hunsaker C (2005) Effects of vegetation patches on soil nutrient pools and fluxes within a mixed-conifer forest. Forest Sci 51:211–220
Freeman DC, Harper KT, Ostler WK (1980) Ecology of plant dioecy in the intermountain region of western North America and California. Oecologia 44:410–417
Gehring JL, Linhart YB (1993) Sexual dimorphism a response to low resources in the dioecious plant Silene latifolia (Caryophylleaceae). Int J Plant Sci 154:152–162
Golodets C, Sternberg M, Kigel J (2009) A community-level test of the leaf-height-seed ecology strategy scheme in relation to grazing conditions. J Veg Sci 20:392–402
Graff P, Rositano F, Aguiar MR (2013) Changes in sex ratios of a dioecious grass with grazing intensity: the interplay between gender traits, neighbour interactions and spatial patterns. J Ecol 101:1146–1157
Gutterman Y (2000) Environmental factors and survival strategies of annual plant species in the Negev Desert, Israel. Plant Spec Biol 15:113–125
Le Houérou H (1990) Bioclimatologie comparative des Zones Aridess.l. de 1’Afrique et 1’Amerique Latine. Terra Arida 7:26–55 (in French)
León RJC, Bran D, Collantes M, Paruelo JM, Soriano A (1998) Grandes unidades de vegetación de la Patagonia extra andina. Ecol Aust 8:125–144 (in Spanish with English abstract)
Mazzarino MJ, Bertiller MB, Schlichter T, Gobbi M (1998) Nutrient cycling in Patagonian ecosystem. Ecol Aust 8:167–181
Milchunas DG, Noy-Meir I (2002) Grazing refuges, external avoidance of herbivory and plant diversity. Oikos 99:113–130
Moreno L, Bertiller MB (2012) Variation of morphological and chemical traits of perennial grasses in arid ecosystems. Are these patterns influenced by the relative abundance of shrubs? Acta Oecol 41:39–45
Moreno L, Bertiller MB (2015) Phenotypic plasticity of morpho-chemical traits of perennial grasses from contrasting environments in arid Patagonia. J Arid Environ 116:96–102
Moreno L, Bertiller MB, Carrera AL (2010) Changes in traits of shrub canopies across an aridity gradient in northern Patagonia, Argentina. Basic Appl Ecol 11:693–701
Mueller-Dombois D, Ellenberg H (1974) Aims and methods of vegetation ecology. Wiley, New York
Norusis MJ (1997) SPSS advanced statistics 7.5. SPSS, Chicago
Obeso JR (2002) The costs of reproduction in plants. New Phytol 155:321–348
Obeso JR, Alvarez-santullano M, Retuerto R (1998) Sex ratios, size distributions, and sexual dimorphism in the dioecious tree Ilex aquifolium (aquifoliaceae). Am J Bot 85:1602–1608
Oesterheld M, Oyarzábal M (2004) Grass-to-grass protection from grazing in a semi-arid steppe. Facilitation, competition, and mass effect. Oikos 107:576–582
Pazos GE, Bisigato AJ, Bertiller MB (2007) Abundance and spatial patterning coexisting perennial grasses in grazed shrublands of the Patagonian Monte. J Arid Environ 70:316–328
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
Retuerto R, Fernandezlema B, Rodriguezroiloa S, Obeso JR (2000) Gender, light and water effects in carbon isotope discrimination, and growth rates in the dioecious tree Ilex aquifolium. Funct Ecol 14:529–537
Rotundo JL, Cipriotti PA, Gundel PE (2006) Morphological and growth responses to water stress of two subpopulations of Bromus pictus from soil with contrasting water availability. Rev Chil Hist Nat 79:65–74
Schlesinger WH, Reynolds JF, Cunningham GL, Huenneke LF, Jarrell WM, Virginia RA, Whitford WG (1990) Biological feedbacks in global desertification. Science 247:1043–1048
Shea MM, Dixon PM, Sharitz RR (1993) Size Differences Sex Ratio, and spatial distribution of male and female water tupelo, Nyssa aquatica (Nyssaceae). Am J Bot 80:26–30
Soriano A (1950) La vegetación del Chubut. Revista Argentina de Agronomía 1:30–66 (in Spanish)
Soriano A, Sala OE, Perelman SB (1994) Patch structure and dynamics in a Patagonian arid steppe. Vegetatio 111:127–135
Tongway D, Ludwig JA (2005) Heterogeneity in arid and semiarid lands. In: Lovett GM, Jones CG, Turner MG, Weathers KC (eds) Ecosystem function in heterogeneous landscapes. Springer, New York, pp 189–205
UNESCO (1979) Carte de la répartition mondiale des régions arides. 1/25.000.000. Notice explicative. UNESCO, Paris (in French)
Valladares F, Sanchez-Gomez D, Zavala MA (2006) Quantitative estimation of phenotypic plasticity: bridging the gap between the evolutionary concept and its ecological applications. J Ecol 94:1103–1116
Waterman PG, Mole S (1994) Extraction and chemical quantification. In: Waterman PG, Mole S (eds) Methods in ecology, analysis of phenolics plant metabolites. Blackwell Scientific Publications, Oxford, pp 66–103
Zaady DR, Groffman PM, Shachak M (1996) Litter as regulator of N and C dynamics in macrophytic patches in Negev desert soils. Soil Biol Biochem 28:39–46
Acknowledgments
This research was supported by Projects PICT 1349-1368 of the National Agency for Scientific and Technological Promotion (ANPCyT) and PIP-112-200801-01664-CONICET. Laura Moreno was supported by a CONICET research fellowship. This research complies with the current laws of Argentina.
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Moreno, L., Bertiller, M.B. Variation of morphological and chemical traits in sexes of the dioecious perennial grass Poa ligularis in relation to shrub cover and aridity in Patagonian ecosystems. Popul Ecol 58, 189–197 (2016). https://doi.org/10.1007/s10144-015-0530-1
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DOI: https://doi.org/10.1007/s10144-015-0530-1