Abstract
Sampling design and three sample treatments prior the application of the seedling emergence method were tested in order to find the best method for seed bank quantification in arid Nama Karoo rangelands. I analyzed species composition and seed densities by contrasting undercanopy and open-matrix samples from two soil depths and by comparing the effects of cold-, heat-, and no stratification on germination rates of species in a greenhouse setting. The soil seed bank showed minimal similarity to the standing vegetation, with only 20 plant species germinated. Spatial distribution of seeds was highly heterogeneous. Nearly 90% of germinated seeds were located in 0- to 4-cm compared to >4- to 8-cm soil depth. Undercanopy seed banks contained significantly more species and seeds than open-matrix seed banks. Neither the number nor the diversity of seeds germinated differed significantly among the three treatments. Cold stratification tended to detect more species and seeds only at >4- to 8-cm soil depth. The results highlight the importance of spatial heterogeneity in the accurate evaluation of soil seed banks in the arid Nama Karoo and the importance of considering seasonal variability in the availability of readily germinable seeds. Data also suggest that sample pretreatment in germination trials may give little return for cost and effort, which emphasizes that it is more important to choose the sampling design most likely to give a representative number of seed bank species. Further studies are needed to analyze seed bank dynamics and species-specific germination requirements to promote recruitment of plant taxa underrepresented in the seed bank.
Similar content being viewed by others
References
Baskin, C. C., & Baskin, J. M. (2001). Seeds. Ecology, biogeography, and evolution of dormancy and germination. San Diego: Academic Press.
Bigwood, D. W., & Inouye, D. W. (1988). Spatial pattern analysis of seed banks: An improved method and optimized sampling. Ecology, 69, 497–507.
Caballero, I., Olano, J. M., Escudero, A., & Loidi, J. (2008). Seed bank spatial structure in semi-arid environments: Beyond the patch-bare area dichotomy. Plant Ecology, 195, 215–223.
Cabral, H., Zuur, A. F., Ieno, E. N., & Smith, G. M. (2007). Analysing presence and absence data for flatfish distribution in the Tagus estuary, Portugal. In A. F. Zuur, E. N. Ieno, & G. M. Smith (Eds.), Analysing ecological data (pp. 389–402). New York: Springer.
Colwell, R. K. (2005). EstimateS: Statistical estimation of species richness and shared species from samples, version 7.5. User’s Guide and application. http://purl.oclc.org/estimates. Accessed 4 August 2009.
Dengler, J. (2009). Which function describes the species–area relationship best? A review and empirical evaluation. Journal of Biogeography, 36, 728–744.
Fenner, M., & Thompson, K. (2005). The ecology of seeds. Cambridge: University Press.
Flores, J., & Jurado, E. (2003). Are nurse-protégé interactions more common among plants from arid environments? Journal of Vegetation Science, 14, 911–916.
Funes, G., Basconcelo, S., Díaz, S., & Cabido, M. (2003). Seed bank dynamics in tall-tussock grasslands along an altitudinal gradient. Journal of Vegetation Science, 14, 253–258.
Germishuizen, G., & Meyer, N. L. (2003). Strelitzia 14, Plants of Southern Africa: An annotated checklist. Pretoria: National Botanical Institute.
Gross, K. L. (1990). A comparison of methods for estimating seed numbers in the soil. Journal of Ecology, 78, 1079–1093.
Guo, Q., Rundel, P. W., & Goodall, D. W. (1999). Structure of desert seed banks: Comparisons across four North American desert sites. Journal of Arid Environments, 42, 1–14.
Gutterman, Y. (2000). Environmental factors and survival strategies of annual plant species in the Negev Desert, Israel. Plant Species Biology, 15, 113–125.
Hoffmann, A., & Zeller, U. (2005). Influence of variations in land use intensity on species diversity and abundance of small mammals in the Nama Karoo, Namibia. Belgian Journal of Zoology, 135, 91–96.
Hopfensperger, K. N. (2007). A review of similarity between seed bank and standing vegetation across ecosystems. Oikos, 116, 1438–1448.
Hulme, P. E. (1998). Post-dispersal seed predation: Consequences for plant demography and evolution. Perspectives in Plant Ecology, Evolution and Systematics, 1, 32–46.
Jones, F. E., & Esler, K. J. (2004). Relationship between soil-stored seed banks and degradation in eastern Nama Karoo rangelands (South Africa). Biodiversity and Conservation, 13, 2027–2053.
Jürgens, N. (1998). Biodiversity monitoring transect analysis. In W. Barthlott & M. Gutmann (Eds.), Biodiversitätsforschung in Deutschland. Potentiale und Perspektiven. Bad Neuenahr-Ahrweiler.
Kassahun, A., Snyman, H. A., & Smit, G. N. (2009). Soil seed bank evaluation along a degradation gradient in arid rangelands of the Somali region, eastern Ethiopia. Agriculture, Ecosystems and Environment, 129, 428–436.
Kemp, P. R. (1989). Seed banks and vegetation processes in deserts. In M. A. Leck, V. T. Parker, & R. L. Simpson (Eds.), Ecology of soil seed banks (pp. 257–281). San Diego: Academic Press.
Kinloch, J. E., & Friedel, M. H. (2005). Soil seed reserves in arid grazing lands of central Australia. Part 1: Seed bank and vegetation dynamics. Journal of Arid Environments, 60, 133–161.
Kinucan, R. J., & Smeins, F. E. (1992). Soil seed bank of a semiarid Texas Grassland under three long-term (36-years) grazing regimes. The American Midland Naturalist, 128, 11–21.
Klintenberg, P., & Seely, M. (2004). Land degradation monitoring in Namibia: A first approximation. Environmental Monitoring and Assessment, 99, 5–21.
Kos, M., & Poschlod, P. (2007). Seeds use temperature cues to ensure germination under nurse-plant shade in xeric Kalahari savannah. Annals of Botany, 99, 667–675.
Li, F. R. (2008). Presence of shrubs influences the spatial pattern of soil seed banks in desert herbaceous vegetation. Journal of Vegetation Science, 19, 537–548.
López, R. P. (2003). Soil seed banks in the semi-arid Prepuna of Bolivia. Plant Ecology, 168, 85–92.
Major, J., & Pyott, W. T. (1966). Buried, viable seeds in two California bunchgrass sites and their bearing on the definition of a flora. Vegetatio, 13, 253–282.
Mendelsohn, J., Jarvis, A., Roberts, C., & Robertson, T. (2002). Atlas of Namibia. A portrait of the land and its people. Cape Town: David Philip Publishers.
Msangi, J. P. (2004). Drought hazard and desertification management in the drylands of Southern Africa. Environmental Monitoring and Assessment, 99, 75–87.
Nathan, R., & Muller-Landau, H. C. (2000). Spatial patterns of seed dispersal, their determinants and consequences for recruitment. Trends in Ecology & Evolution, 15, 278–285.
Navie, S. C., Cowley, R. A., & Rogers, R. W. (1996). The relationship between distance from water and the soil seed bank in a grazed semi-arid subtropical rangeland. Australian Journal of Botany, 44, 421–431.
Nelson, J. F., & Chew, R. M. (1977). Factors affecting seed reserves in the soil of a Mojave Desert ecosystem, Rock Valley, Nye County, Nevada. The American Midland Naturalist, 97, 300–320.
Noronha, A., Andersson, L., & Milberg, P. (1997). Rate of change in dormancy level and light requirement in weed seeds during stratification. Annals of Botany, 80, 795–801.
Page, M. J., Baxter, G. S., & Lisle, A. T. (2006). Evaluating the adequacy of sampling germinable soil seed banks in semi-arid systems. Journal of Arid Environments, 64, 323–341.
Price, M. V., & Joyner, J. W. (1997). What resources are available to desert granivores: Seed rain or soil seed bank? Ecology, 78, 764–773.
Quinn, G. P., & Keough, M. J. (2002). Experimental design and data analysis for biologists. Cambridge: Cambridge University Press.
Reichman, O. J. (1979). Desert granivore foraging and its impact on seed densities and distributions. Ecology, 60, 1085–1092.
Reichman, O. J. (1984). Spatial and temporal variation of seed distributions in Sonoran Desert soils. Journal of Biogeography, 11, 1–11.
Roberts, H. A. (1981). Seed banks in soils. In T. H. Coaker (Ed.), Advances in applied biology (Vol. 6, pp. 1–55). London: Academic Press.
Snyman, H. A. (2004). Soil seed bank evaluation and seedling establishment along a degradation gradient in a semi-arid rangeland. African Journal of Range and Forage Science, 21, 37–47.
Solomon, T. B., Snyman, H. A., & Smit, G. N. (2006). Soil seed bank characteristics in relation to land use systems and distance from water in a semi-arid rangeland of southern Ethiopia. South African Journal of Botany, 72, 263–271.
SPSS Inc. (2007). SPSS for Windows, Version 15.0.1. Chicago, SPSS Inc.
StatSoft Inc. (2007). STATISTICA for Windows. Version 8.0. http://www.statsoft.com/.
Thompson, K., & Grime, J. P. (1979). Seasonal variation in the seed banks of herbaceous species in ten contrasting habitats. Journal of Ecology, 67, 893–921.
Thompson, K., Bakker, J. P., & Bekker, R. M. (1997). The soil seed banks of North West Europe: Methodology, density and longevity. Cambridge: Cambridge University Press.
Veenendaal, E. M., & Ernst, W. H. O. (1991). Dormancy patterns in accessions of caryopses from savanna grass species in South Eastern Botswana. Acta Botanica Neerlandica, 40, 297–309.
Venable, D. L., & Brown, J. S. (1988). The selective interactions of dispersal, dormancy, and seed size as adaptations for reducing risk in variable environments. The American Naturalist, 131, 360–384.
Vleeshouwers, L. M., Bouwmeester, H. J., & Karssen, C. M. (1995). Redefining seed dormancy: An attempt to integrate physiology and ecology. Journal of Ecology, 83, 1031–1037.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Dreber, N. How best to quantify soil seed banks in arid rangelands of the Nama Karoo?. Environ Monit Assess 173, 813–824 (2011). https://doi.org/10.1007/s10661-010-1425-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10661-010-1425-4