Projectdetails

Titel	:	Contagious seed dispersal and shared natural enemies: factors promoting tropical tree diversity?
Hoofdaanvrager	:	Dr. ir. P.A. Jansen
Verbonden aan	:	Rijksuniversiteit Groningen Faculteit Wiskunde en Natuurwetenschappen Centrum voor Ecologische en Evolutionaire Studies
Uitvoerder(s)	:	Dr. ir. P.A. Jansen
Plaats van uitvoering	:	geen informatie beschikbaar
Looptijd	:	05/15/2007 tot 06/14/2011
Strategisch doel	:	Talent
Budget	:	Eur 140,608.00 voor personele kosten
Subsidie-instrument	:	Vernieuwingsimpuls Veni

Samenvatting

Tropical forests are astonishingly rich in tree species. How so many species manage to coexist is an unresolved question in ecology. Seed dispersal and density-dependent mortality are central processes in the major current theories explaining tropical tree diversity. However, theorists usually model dispersal using smooth, leptokurtic functions. This may be inadequate, because most tropical forest tree species are dispersed by frugivorous animals, which tend to provide ?contagious dispersal?: seeds are deposited very patchily and locally, independent of dispersal distance, into multi-species aggregations.

Contagiousness of dispersal probably strongly affects seed survival and seedling establishment. Not only is seed survival dependent on the density of conspecific seeds, survival may also be affected indirectly, positively or negatively, by the presence of heterospecific seeds through the action of shared natural enemies (?apparent competition?). If contagious dispersal and apparent competition are commonplace, dispersal and predation may promote tree species coexistence more than is currently thought.

I propose to study the occurrence and consequences of contagious dispersal and apparent competition in the tropical moist forest of Barro Colorado Island (BCI), Panama. Aims are to (1) determine to what degree seed dispersal is spatially contagious, (2) investigate the consequences of contagious dispersal for patterns of seed survival and seedling establishment, and (3) evaluate whether contagious dispersal and apparent competition can promote tree species coexistence.

I will analyze five unique databases that exist for BCI, including a 19-year record of seed rain into 200 fruit traps, a 5-year record of seedling recruitment in 600 adjacent quadrats, and seedling recruitment in 20,000 quadrats throughout 50 ha of extensively mapped forest. I will do field experiments on seed attractiveness to rodents (the main generalist seed predators), context-dependent seed predation, and seedling establishment. Finally, I will model dispersal and predation to explore how contagiousness and apparent competition affect species diversity.

Producten

Artikelen

• D. Galvez, Dr. ir. P.A. Jansen (2007). Bruchid beetle infestation and the value of Attalea butyracea endocarps for Neotropical rodents. Journal of Tropical Ecology. pp. 381-384. ISSN 0266-4674.
• P.M. Forget, Dr. ir. P.A. Jansen (2007). Hunting increases dispersal limitation in the tree Carapa procera, a non-timber forest product. Conservation Biology. pp. 106-113. ISSN 0888-8892.
• V. Acácio, M. Holmgren, O. Schrotter, Dr. ir. P.A. Jansen (2007). Multiple recruitment limitation causes arrested succession in Mediterranean cork oak systems. Ecosystems. pp. 1220-1230. ISSN 1432-9840.
• P.L.B. Kunne, P.J. Van der Meer, A.M.H. Brunsting, L.A. Dibor, Dr. ir. P.A. Jansen (2008). Evidence for scatter-hoarding in a tropical peat swamp forest in Sarawak, Malaysia. Journal of Tropical Forest Science. pp. 340-343. ISSN 0128-1283.
• S.J. Wright, H. Olff, C.X. Garzon-Lopez, S.A. Bohlman, H.C. Muller-Landau, Dr. ir. P.A. Jansen (2008). Large-scale spatial variation in palm fruit abundance across a tropical moist forest estimated from high-resolution aerial photographs. Ecography. pp. 33-42. ISSN 1600-0587.
• F. Bongers, R. Dudley, S. Wunder, D. Sheil, Dr. ir. P.A. Jansen (2008). Hope for Bohemian ecologists?. Comments on "?A possible role of social activity to explain differences in publication output among ecologists?"? by Tomás Grim, Oikos 2008. Web Ecology. pp. 103-105. ISSN 1399-1183.
• P.J. Van der Meer, F. Bongers, Dr. ir. P.A. Jansen (2008). Is farther seed dispersal better?. Spatial patterns of offspring mortality in three rainforest tree species with different dispersal abilities. Ecography. pp. 43-52. ISSN 1600-0587.
• F.J.J.M. Bongers, P.J. Van der Meer, Dr. ir. P.A. Jansen (2008). Spatial contagiousness of canopy disturbance in tropical rainforest. an individual-tree based test. Ecology. pp. 3490-3503. ISSN 0012-9658 .
• R.W. Kays, B. Kranstauber, D. Gálvez, Dr. ir. P.A. Jansen (2009). Scatter hoarding by the Central American agouti. a test of optimal cache spacing theory. Animal Behaviour. pp. 1327-1333. ISSN 0003-3472.
• N. Diaz, C Smit, Dr. ir. P.A. Jansen (2009). Establishment limitation of holm oak (Quercus ilex subsp. ballota (Desf.) Samp.) in a Mediterranean savanna - forest ecosystem. Annals of Forest Science. pp. 511p1-7. ISSN 1286-4560.
• T.D. Lambert, E. Aliaga-Rossel, M. Wikelski, R.W. Kays, Dr. ir. P.A. Jansen (2009). Nocturnal activity by the primarily diurnal Central American agouti (Dasyprocta punctata) in relation to environmental conditions, resource abundance and predation risk. Journal of Tropical Ecology. pp. 211-215. ISSN 0266-4674.
• H.C. Muller-Landau, S.J. Wright, Dr. ir. P.A. Jansen (2010). Bushmeat hunting, tropical biodiversity and carbon. An indirect link. Science. pp. 30-30. ISSN 0036-8075.
• S.J. Wright, P.J. Verkerk, K. Elschot, Dr. ir. P.A. Jansen (2010). Seed predation and defleshing in the agouti-dispersed palm Astrocaryum standleyanum. Journal of Tropical Ecology. pp. 473-480
• D. Caillaud, C.X. Garzon-Lopez, P.D. Walsh, S.V. Scarpino, A.J.S. Winkelhagen, S.A. Bohlman, M.C. Crofoot, Dr. ir. P.A. Jansen (2010). Modeling the Spatial Distribution and Fruiting Pattern of a Key Tree Species in a Neotropical Forest. Methodology and Potential Applications. PLoS ONE. pp. e15002-10pp. ISSN 1932-6203.
• R.W. Kays, B. Kranstauber, C. Carbone, J.M. Rowcliffe, Dr. ir. P.A. Jansen (2011). Quantifying the sensitivity of camera traps. an adapted distance sampling approach.. Methods in Ecology and Evolution. pp. x-x. ISSN 2041-210X.

Bijdragen aan boeken

• P.M. Forget, D.A. Westcott, J.E. Lambert, S.J. Mazer, S. Kitamura, A.J. Dennis, Dr. ir. P.A. Jansen, D.A. Westcott, A.J. Dennis, E.W. Schupp, R.J. Green (2007). Seed allometry and disperser assemblages in tropical rain forests: a comparison of four floras on different continents. in: Seed dispersal. Wallingford: . pp. 5-36. ISBN 9781845931650.