Abstract
The arborescent legume, honey mesquite (Prosopis glandulosa), appears to play a central role in patch dynamics of southern Texas savannas by modifying soils and microclimate and by facilitating the ingress, establishment and/or growth of shrubs in its understorey. As an indirect test for the occurrence and persistence of facilitation in mature shrub clusters (patches), we examined the gas exchange, water relations and production of associated shrubs growing in patches where a Prosopis overstorey was present and in patches where Prosopis had succumbed to natural mortality. Surface (0–10 cm) soils associated with shrub patches were enriched in total [N] and [C] compared to soils of neighboring herbaceous zones. However, there were no detectable differences in soil [N] or [C] in patches with and without Prosopis. Foliar [N] and biomass of various shrub species were also statistically comparable for patches with and without Prosopis. These results are in accordance with other studies that indicate the nutrient legacy associated with Prosopis occupation of a patch may persist for decades after its demise. In comparison to plants growing in the absence of Prosopis, leaf water potentials (predawn and midday), and net photosynthesis and water vapor conductance (morning and midday) of outer-canopy sunlit leaves over an annual growth cycle were comparable for two common evergreen shrubs, Zanthoxylum fagara and Berberis trifoliolata, growing in patches with a live Prosopis. These findings indicate that the presence of Prosopis was not enhancing the growth or activity of mature understorey shrubs; facilitation may, therefore, be important only during early stages of cluster development. In addition, we found no indication that the loss of Prosopis has initiated a downward phase in a cyclic succession of patch initiation, growth and death. Rather, the understorey shrubs appear to be able to maintain growth and productivity in the absence of a Prosopis overstorey, and may, therefore, represent persistent components of woody patches on these savanna landscapes.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Aguiar MR, Sala OE (1994) Competition, facilitation, seed distribution and the origin of patches in a Patagonian steppe. Oikos 70: 26–34
Aguiar MR, Soriano A, Sala OE (1992) Competition and facilitation in the recruitment of seedlings in Patagonian steppe. Funct Ecol 6: 66–70
Archer S (1989) Have southern Texas savannas been converted to woodlands in recent history? Am Nat 134: 545–561
Archer S (1995) Tree-grass dynamics in a Prosopis-thornscrub savanra parkland: reconstructing the past and predicting the future. Ecoscience 2: 83–99
Archer S, Scifres C, Bassham CR, Maggio R (1988) Autogenic succession in a subtropical savanna: conversion of grassland to thorn woodland. Ecol Monogr 58: 111–127
Belsky AJ (1994) Influences of trees on savanna productivity: tests of shade, nutrients, and tree-grass competition. Ecology 75:922–932
Belsky AJ, Amundson RG, Duxbury JM, Riha SJ, Ali AR, Mwonga SM (1989) The effects of trees on their physical, chemical and biological environment in a semi-arid savanna in Kenya. J Appl Ecol 26: 1005–1024
Belsky AJ, Canham CD (1994) Forest gaps and isolated savanna trees: an application of patch dynamics in two ecosystems. Bioscience 44: 77–84
Caldwell MM, Richards JH, Beyschlag W (1991) Hydraulic lift: ecologioal implications of water efflux from roots. In: Atkinson D (ed) Plant root growth: an ecological perspective. Blackwell, Oxford, pp 423–436
Callaway RM (1992) Effect of shrubs on recruitment of Quercus douglasii and Quercus lobata in California. Ecology 73: 2118–2128
Carter MG (1964) Effects of drouth on mesquite J Range Manage 17: 275–276
Correll DS Johnston MC (1979) Manual of the vascular plants of Texas. University of Texas Press, Richardson
Fernández-A RJ, Sala OE, Golluscio RA (1991) Woody and herbaceous aboveground production of a Patagonian steppe. J Range Manage 44: 434–437
Field C, Mooney HA (1983) Leaf age and seasonal effects on light, water, and nitrogen use efficiency in a California shrub. Oecologia 56: 348–355
Flinn RC, Scifres CJ, Archer S (1992) Variations in basal sprouting in five co-occurring shrubs: implications for stand dynamics. J Veg Sci 3: 125–128
Fowler N (1988) Grasslands nurse trees and coexistence. In: Amos BB, Gehlbach FR (eds) Edwards Plateau vegetation: plant ecological studies in Central Texas. Baylor University Press, Waco, pp 91–100
Franco AC, Nobel PS (1988) Interactions between seedlings of Agave deserii and the nurse plant Hilaria rigida. Ecology 69: 1731–1740
Franco AC, Nobel PS (1990) Influences of root distribution and growth on predicted water uptake and interspecific competition. Oecologia 82: 151–157
Franco-Pizaña J, Fulbright TE, Gardiner DT (1995) Spatial relations between shrubs and Prosopis glandulosa canopies. J Veg Sci 6: 73–78
Hacker RB (1984) Vegetation dynamics in a grazed mulga shrubland community. I. The mid-storey shrubs. Aust J Bot 32: 239–249
Johnson HB, Mayeux Jr HS (1990) Prosopis glandulosa and the nitrogen balance of rangelands: extent and occurrence of nodulation. Oecologia 84: 176–185
Kellman M (1979) Soil enrichment by neotropical savanna trees. J Ecol 67: 565–577
Klemmedson JO, Tiedemann AR (1986) Long-term effects of mesquite removal on soil characteristics: II. Nutrient availability. Soil Sci Soc Am J 50: 476–480
Lonard RI, Judd FW (1985) Effects of a severe freeze on native woody plants in the Lower Rio Grande Valley, Texas. Southwest Nat 30: 397–403
Loomis LE (1989) Plant-soil relationships in grassland-to-woodland succession. PhD Dissertation, Texas A&M University, College Station
McAuliffe JR (1984) Sahuaro-nurse tree associations in the Sonoran Desert: competitive effects of sahuaros. Oecologia 64: 319–321
McLendon T (1991) Preliminary description of the vegetation of south Texas exclusive of coastal saline zones. Tex J Sci 43: 13–32
McPherson GR, Wright HA, Wester DB (1988) Patterns of shrub invasion in semiarid Texas grasslands. Am Midl Nat 120: 391–397
Midwood AJ, Boutton TW, Watts SE, Archer S (1993) Natural abundance of 2H and 18O in soil moisture, rainfall and plants in a subtropical thorn woodland ecosystem: implications for plant water use. In: International symposium on applications of isotope techniques in studying past and current environmental changes in the hydrosphere and atmosphere. International Atomic Energy Agency, Vienna, pp 419–431
Mooney HA, Simpson BB, Solbrig OT (1977) Phenology, morphology, physiology. In: Simpson BB (ed) Mesquite. Its biology in two desert scrub ecosystems. Dowden Hutchinson and Ross, Stroudsburg, pp 26–43
Nelson DW, Somers LE (1980) Total-nitrogen analysis of soil and plant tissues. J Assoc Anal Chem 63: 770–780
Nilsen ET, Rundel PW, Sharifi MR (1981) Summer water relations of the desert phreatophyte Prosopis glandulosa in the Sonoran Desert of southern California. Oecologia 50: 271–276
Pella E, Colombo B (1973) Study of carbon, hydrogen and nitrogen determination by combustion-gas chromatography. Mikrochim Acta 1973: 697–719
Rykiel EJ Jr, Cook TL (1986) Hardwood-redcedar clusters in the post oak savanna of Texas. Southwest Nat 31: 73–78
Sala OE, Golluscio RA, Lauernroth WK, Soriano A (1989) Resource partitioning between shrubs and grasses in the Patagonian steppe. Oecologia 81: 501–505
Scanlan JC (1988) Spatial and temporal vegetation patterns in a subtropical Prosopis savanna woodland, Texas. PhD Dissertation, Texas A&M University, College Station
Scanlan JC, Archer S (1991) Simulated dynamics of succession in a North American subtropical Prosopis savanna. J Veg Sci 2: 625–634
Smith TM, Goodman PS (1987) Successional dynamics in an Acacia nilotica-Euclea divinorum savannah in southern Africa. J Ecol 75: 603–610
Soriano A, Sala OE, Perelman SB (1994) Patch structure and dynamics in a Patagonian arid steppe. Vegetatio 111: 127–135
Stuart-Hill GC, Tainton NN, Barnard HJ (1987) The influence of an Acacia karoo tree on grass production in its vicinity. J Grass Soc S Afr 4: 83–88
Tiedemann AR, Klemmedson JO (1986) Long-term effects of mesquite removal on soil characteristics: I. Nutrients and bulk density. Soil Sci Soc Am Proc 50: 472–475
Tupas GL, Sajise PE (1977) The role of savanna trees in plant succession. I. Ecological conditions associated with tree clumps. Philipp J Biol 6: 229–244
Vetaas OR (1992) Micro-site effects of trees and shrubs in dry savannas. J Veg Sci 3: 337–344
Virginia RA, Jarrell WM (1983) Soil properties in a mesquitedominated Sonoran Desert ecosystem. Soil Sci Soc Am J 47: 138–144
Virginia RA, Baird LM, La Favre JS, Jarrell WM, Bryan BA, Shearer G (1984) Nitrogen fixation efficiency, natural 15N abundance and morphology of mesquite (Prosopis glandulosa) root nodules. Plant Soil 79: 273–284
Watt AS (1947) Pattern and process in the plant community. J Ecol 35: 1–22
Watts SE (1993) Rooting patterns of co-occurring woody plants on contrasting soils in a subtropical savanna. MS Thesis, Texas A&M University, College Station
Whittaker RH, Gilbert LE, Connell JH (1979) Analysis of two-phase pattern in a mesquite grassland, Texas. J Ecol 67: 935–952
Yeaton RI (1978) A cyclic relationship between Larrea tridentata and Opuntia leptocaulis in the northern Chihuahuan Desert. J Ecol 66: 651–656
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Barnes, P.W., Archer, S. Influence of an overstorey tree (Prosopis glandulosa) on associated shrubs in a savanna parkland: implications for patch dynamics. Oecologia 105, 493–500 (1996). https://doi.org/10.1007/BF00330012
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00330012