Abstract
Background and aims – North Saharan Acacia woodland is a fragile ecosystem altered by desertification and human activities. Little research has been conducted on the ecology of North Saharan Acacia woodland species. Seed size is a key trait to determine germination success, survival rate and establishment of Acacia woodland species under desert constraints.
Methods – We analysed seed-size relationships in 42 selected woody plants in four different types of Acacia woodland vegetation which correspond to 26 plant species. We examined the correlation among seed size, fruit size, plant height, leaf size and flowering time and we tested seed size and fruit size variation among growth forms, dispersal modes and mechanisms to prevent dispersal.
Key results – Close relationships were found between seed size and fruit size (r = 0. 77**), between fruit size and plant height (r = 0.51**) and between seed size and flowering duration (r = -0.46*) and a weak positive relationship was found between fruit and leaf size. Species with restricted spatial dispersal tended to have smaller seeds and fruits compared to those with well-developed spatial dispersal. Species which disperse and germinate throughout the year tended to have large diaspores, whereas species with seasonal germination tended to have small diaspores. The relationship between seed size and growth form/plant height was strong for gravity-dispersed (barochorous) species secondarily dispersed by vertebrates (Ziziphus lotus), seeds with secondary wind-assisted dispersal (Zilla spinosa subsp. macroptera) and for restricted-dispersal species (Tetraena gaetula). Precocious, short-flowering species that spread dispersal and germination over time (Acacia tortilis subsp. raddiana) tended to have large seeds. Early- and long-flowering herbaceous species tended to have small seeds (Brocchia cinerea).
Conclusion – Close relationships are found between seed size and fruit size, between fruit size and plant height and between seed size and flowering duration in Moroccan Acacia woodland species.
References
AEFCS (1996) Plan Directeur des aires Protégées du Maroc vols 1–5. Administration Génerale Eaux et Forêts/BCEOM-SECA. [Master plan of the protected areas in Morocco vols 1–5. General Management of Forests and Water/BCEOM-SECA].
Angiosperm Phylogeny Group (2016) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society 181: 1–20. https://doi.org/10.1111/boj.12385
Baker H.G. (1972) Seed weight in relation to environmental conditions in California. Ecology 53: 997–1010. https://doi.org/10.2307/1935413
Bolmgren K., Eriksson O., Linder H.P. (2003) Contrasting flowering phenology and species richness in abiotically and biotically pollinated angiosperms. Evolution 57: 2001–2011. https://doi.org/10.1111/j.0014-3820.2003.tb00380.x
Bolmgren K., Cowan P.D. (2008) Time-size tradeoffs: a phylogenetic comparative study of flowering time, plant height and seed mass in a north-temperate flora. Oikos 117: 424–429. https://doi.org/10.1111/j.2007.0030-1299.16142.x
Bowers J.E., Dimmitt M.A. (1994) Flowering phenology of six woody plants in the northern Sonoran Desert. Bulletin of the Torrey Botanical Club 121: 215–229. https://doi.org/10.2307/2997177
Braun-Blanquet J. (1952) Phytosociologie appliquée. Communications de la Station Internationale de Géobotanique Méditerranéenne et Alpine, Montpellier, no. 116: 156–161. Montpellier, Station Internationale de Géobotanique Méditerranéenne et Alpine.
Cloudsley-Thompson J.L. (1984) Sahara Desert. Oxford, Pergamon Press.
Cornelissen J.H.C. (1999) A triangular relationship between leaf size and seed size among woody species: allometry, ontogeny, ecology and taxonomy. Oecologia 118: 248–255. https://doi.org/10.1007/s004420050725
Cornelissen J.H.C., Lavorel S., Garnier E., Díaz S., Buchmann N., Gurvich D.E., ter Steege H., Morgan H.D., van der Heijden M.G.A., Pausas J.G., Poorter H. (2003) A handbook of protocols for standardized and easy measurement of plant functional traits worldwide. Australian Journal of Botany 51: 335–380. https://doi.org/10.1071/BT02124
Corner E.J.H. (1949) The durian theory or the origin of the modern tree. Annals of Botany 13: 367–414. https://doi.org/10.1093/oxfordjournals.aob.a083225
Ellner S., Shmida A. (1981) Why are adaptations for long-range seed dispersal rare in desert plants? Oecologia 51: 133–144. https://doi.org/10.1007/BF00344663
Euro+Med (2006–2018) Euro+Med PlantBase – The information resource for Euro-Mediterranean plant diversity. Available from http://ww2.bgbm.org/EuroPlusMed/ [accessed 24 Jan. 2018].
Gutterman Y. (2001) Regeneration of plants in arid ecosystems resulting from patch disturbance. Geobotany 27. Dordrecht, Kluwer Academic Publishers. https://doi.org/10.1007/978-94-015-9630-5
Jurado E., Westoby M., Nelson D. (1991) Diaspore weight, dispersal, growth from and perenniality of Central Australian plants. Journal of Ecology 79: 811–830. https://doi.org/10.2307/2260669
Jurado E., Estrada E., Moles A. (2001) Characterizing plant attributes with particular emphasis on seeds in Tamaulipan thornscrub in semi-arid Mexico. Journal of Arid Environments 48: 309–321. https://doi.org/10.1006/jare.2000.0762
Le Houérou H.N. (1997) Climate, flora and fauna changes in the Sahara over the past 500 million years. Journal of Arid Environments 37: 619–647. https://doi.org/10.1006/jare.1997.0315
Leishman M.R., Westoby M., Jurado E. (1995) Correlates of seed size variation: a comparison among five temperate floras. Journal of Ecology 83: 517–529. https://doi.org/10.2307/2261604
Leishman M.R., Wright I.J., Moles A.T., Westoby M. (2000) The evolutionary ecology of seed size. In: Fenner M. (ed.) Seeds: the ecology of regeneration in plant communities: 31–57. Wallingford, UK, CABI. https://doi.org/10.1079/9780851994321.0031
Linting M., Meulman J.J., Groenen P.J., van der Koojj A.J. (2007) Nonlinear principal components analysis: introduction and application. Psychological Methods 12: 336–358.
Mazer S.J. (1989) Ecological, taxonomic, and life history correlates of seed mass among Indiana dune angiosperms. Ecological Monographs 59: 153–175. https://doi.org/10.2307/2937284
Mazer S.J. (1990) Seed mass of Indiana dune genera and families: taxonomic and ecological correlates. Evolutionary Ecology 4: 326–357. https://doi.org/10.1007/BF02270931
McIntosh M.E. (2002) Flowering phenology and reproductive output in two sister species of Ferocactus (Cactaceae). Plant Ecology 159: 1–13. https://doi.org/10.1023/A:1015589002987
Moles A.T., Ackerly D.D., Webb C.O., Tweddle J.C., Dickie J.B., Westoby M. (2005) A brief history of seed size. Science 307: 576–580. https://doi.org/10.1126/science.1104863
Navarro T., Alados C.L., Cabezudo B. (2006) Changes in plant functional types in response to goat and sheep grazing in two semi-arid shrublands of SE Spain. Journal of Arid Environments 64: 298–322. https://doi.org/10.1016/j.jaridenv.2005.05.005
Navarro T., Pascual V., Alados C.L., Cabezudo B. (2009a) Growth form, dispersal strategies and taxonomic spectrum in a semi-arid shrubland in SE Spain. Journal of Arid Environments 73: 103–112. https://doi.org/10.1016/j.jaridenv.2008.09.009
Navarro T., El Oualidi J., Taleb M.S., Pascual V., Cabezudo B. (2009b) Dispersal traits and dispersal patterns in an oro-Mediterranean thorn cushion plant formation of eastern High Atlas, Morocco. Flora 204: 658–672. https://doi.org/10.1016/j.flora.2008.08.005
Noy-Meir I. (1973) Desert ecosystems: environment and producers. Annual Review of Ecology and Systematics 4: 25–51. https://doi.org/10.1146/annurev.es.04.110173.000325
Orshan G. (1982) Monocharacter growth form types as a tool in an analytic-synthetic study of growth forms in Mediterranean type ecosystems. A proposal for an inter-regional program. Ecologia Mediterranea 8: 159–171.
Pérez-Harguindeguy N., Díaz S., Garnier E., Lavorel S., Poorter H., Jaureguiberry P., Bret-Harte M.S., Cornwell W.K., Craine J.M., Gurvich D.E., Urcelay C., Veneklaas E.J., Reich P.B., Poorter L., Wright I.J., Ray P., Enrico L., Pausas J.G., de Vos A.C., Buchmann N., Funes G., Quétier F., Hodgson J.G., Thompson K., Morgan H.D., ter Steege H., van der Heijden M.G.A., Sack L., Blonder B., Poschlod P., Vaieretti M.V., Conti G., Staver A.C., Aquino S., Cornelissen J.H.C. (2013) New handbook for standardised measurement of plant functional traits worldwide. Australian Journal of Botany 61: 167–234. https://doi.org/10.1071/BT12225
Primack R.B. (1987) Relationships among flowers, fruits and seeds. Annual Review of Ecology and Systematics 18: 409–430. https://doi.org/10.1146/annurev.es.18.110187.002205
Quézel P. (1965) La végétation du Sahara, du Tchad à la Mauritanie. Stuttgart, Fisher Verlag.
Quézel P., Barbero M., Benabid A., Rivas-Martínez S. (1994) Le passage de la végétation méditerranéenne à la végétation saharienne sur le revers méridional du Haut Atlas oriental (Maroc). Phytocoenologia 22: 537–582. https://dx.doi.org/10.1127/phyto/22/1994/537
Roux F., Touzet P., Cuguen J., Le Corre V. (2006) How to be early flowering: an evolutionary perspective. Trends in Plant Science 11: 375–381. https://doi.org/10.1016/j.tplants.2006.06.006
Silberbauer-Gottsberger I. (1984) Fruit dispersal and trypanocarpy in Brazilian cerrado grasses. Plant Systematics and Evolution 147: 1–27. https://doi.org/10.1007/BF00984577
SPSS Inc. (2006) SPSS for Windows, Version 15.0. Chicago, SPSS Inc.
van Rheede van Oudtshoorn K., van Rooyen M.W. (1999) Dispersal biology of desert plants. New York, Springer. https://doi.org/10.1007/978-3-662-03561-0
van Rooyen M.W., Theron G.K., Grobbelaar N. (1990) Life form and dispersal spectra of the Namaqualand, South Africa. Journal of Arid Environments 19: 133–145.
Weiher E., van der Werf A., Thompson K., Roderick M., Garnier E., Eriksson O. (1999) Challenging Theophrastus: a common core list of plant traits for functional ecology. Journal of Vegetation Science 10: 609–620. https://doi.org/10.2307/3237076
Westoby M., Jurado E., Leishman M. (1992) Comparative evolutionary ecology of seed size. Trends in Ecology & Evolution 7: 368–372. https://doi.org/10.1016/0169-5347(92)90006-W
Westoby M. (1998) A leaf-height-seed (LHS) plant ecology strategy scheme. Plant and Soil 199: 213–227. https://doi.org/10.1023/A:1004327224729
Westoby M., Falster D.S., Moles A.T., Vesk P.A., Wright I.J. (2002) Plant ecological strategies: some leading dimension of variation between species. Annual Review of Ecology and Systematics 33: 125–159. https://doi.org/10.1146/annurev.ecolsys.33.010802.150452
White F. (1983) The vegetation of Africa: a descriptive memoir to accompany the UNESCO/AETFAT/UNSO vegetation map of Africa. Paris, UNESCO.
Willson M.F. (1993) Dispersal mode, seed shadows, and colonization patterns. Vegetatio 108: 261–280.
Wright I.J., Ackerly D.D., Bongers F., Harms K.E., Ibarra-Manriquez G., Martinez-Ramos M., Mazer S.J., Muller-Landau H., Paz H., Pitman N.C.A., Poorter L., Silman M.R., Vriesendorp C.F., Webb C.O., Westoby M., Wright S.J. (2007) Relationships among ecologically important dimensions of plant trait variation in seven Neotropical forests. Annals of Botany 99: 1003–1015. https://doi.org/10.1093/aob/mcl066
Wulff R.D. (1986) Seed size variation in Desmodium paniculatum. III. Effects on reproductive yield and competitive ability. Journal of Ecology 74: 115–121. https://doi.org/10.2307/2260352
WWF & IUCN (1994) Centres of plant diversity. A guide and strategy for their conservation. Volume 1. Europe, Africa, South West Asia and the Middle East. Cambridge, U.K., IUCN Publications Unit.
Yassin M., Mandouri T., Aafi A., Taleb M.S., Bellaka M., Maghnoug M., Hanane S., Ramandé A., Hammoudou M., Bellayachi K. (2002) Rapport scientifique de l’Observatoire ROSELT/OSS de l’Oued Mird (Province de Zagoura, Maroc). Rabat, Haut-Commissariat aux Eaux et Forêts et à la Lutte Contre la Désertification, Division de Recherche et Expérimentations Forestières.
Yassin M., Mandouri T., Oudadda A., El Ouardi M., Taleb M.S., Aafi A., Bellaka M., Maghnoug M., Hanane S., Ramdane A., Benidir M., Hammoudou M., Bellayachi K. (2005) Deuxième rapport de surveillance de l’Observatoire ROSELT/OSS de l’Oued Mird (Province de Zagoura, Maroc). Rabat, Haut-Commissariat aux Eaux et Forêts et à la Lutte Contre la Désertification, Division de Recherche et Expérimentations Forestières.
When submitting to the journal, you have read and agree to our copyright and open access policy.