totes Crosses between members of commonly separated communities, therefore, can get give progeny regarding suboptimal fitness due to outbreeding despair (Bateson, 1978; Price and you can Waser, 1979). Really proof outbreeding depression when you look at the plant life derives out-of crosses ranging from communities (e.g., Ritland and you may Ganders, 1987; Sobrevila, 1988; Fischer and you may Matthies, 1997). But not, evidence of outbreeding depression contained in this populations could have been said getting an excellent pair kinds (Waser and you can Price, 1983, 1989, 1991, 1993, 1994; Schemske and you can Pautler, 1984; Waser et al., 1987; McCall, Mitchell-Olds, and you can Waller, 1988). Ultimate consequences regarding outbreeding despair ought to include support out of reproductive isolation from the distance and you will enhanced hereditary differentiation more than particular spatial measure, possibly leading to speciation. Within the exotic woods, patterns for the development away from high forest types assortment generally invoke genetic divergence regarding communities over some spatial size (e.grams., Fedorov, 1966; Ashton, 1969). Little is famous, not, of the spatial scale out-of genetic divergence in the warm forest species.
Whenever you are trends for the outbreeding anxiety have been noted to have lots out of bush types (citations over), there are no penned accounts out of outbreeding depression in any tree forest (Coles and Fowler, 1976; Park and you may Fowler, 1982, 1984; Crome and you may Irvine, 1986; Hardner, Potts, and you may Gore, 1998). This research assesses the importance and you can estimate spatial measure from outbreeding depression (while the a good proxy to have genetic divergence) in 2 tropical tree kinds by way of exercise evaluations regarding much time-range crosses having crosses more small and you can moderate distances.
Each from a couple of tropical tree species, the second questions had been handled: (1) Why does cross-fertility will vary having outcrossing point? (2) What is the possibility inbreeding depression into the close-neighbor crosses? (3) What’s the possibility of outbreeding depression more better ranges contained in this and you can anywhere between forest reserves? and (4) How do brand new strengths out-of inbreeding and you may outbreeding effects are very different one of very early existence records degrees, in addition to seed products set, seed germination, additionally the survivorship and development of seedlings?
Investigation web site and varieties
It really works try carried out in the bedroom of one’s choses à savoir quand on sort avec une personne de son âge aseasonal Sinharaja Business Society Site, a keen 8800-ha, UNESCO Kid and the Biosphere Set-aside, located in the southwestern wet region away from Sri Lanka (Fig. 1). Brand new woods away from southwestern Sri Lanka is really disconnected once the a consequence of clearing getting coffee-and rubberized plantations one to happened when you look at the Uk colonial months (>100 year before)pared to a lot of warm precipitation forests, the flowers from Sinharaja is fairly kinds-poor (?230 types of woody plant life), but characterized by highest endemism (Gunatilleke and Gunatilleke, 1980). The analysis kinds (Syzygium rubicundum and Shorea cordifolia) was in fact selected so you’re able to represent two of the major cover-dominant, economically very important genera of your island’s rain forests. Both types is pollinated mainly of the bees (Apis spp.) and develop single-seeded good fresh fruit. Both variety differ in mode out-of seed products dispersal (bird- otherwise bat-dispersal versus. wind- or gyration-dispersal) and they are likely to exhibit additional populace genetic formations in the absolute stands (Loveless and Hamrick, 1984; Hamrick, Murawski, and you can Nason, 1993). The fresh new communities directed for it study, but not, occurred in 25+-yr-old logged forest at the Sinharaja Put aside. Grownups of each kinds is highly clumped about signed forest in accordance with the withdrawals within the unlogged really stands. This contrast implies that the people formations of those variety provides become altered about highest-light, post-signing ecosystem, in which regeneration most likely led to this new place out-of categories of sibs or otherwise relevant some body. The study populations, therefore, offered a great possible opportunity to evaluate the possibility biparental inbreeding despair within the tree trees.
Material And methods
Syzygium rubicundum (Myrtaceae), hence generally plants a year, try a prominent canopy types of mid-hill elements close by Sinharaja. Mature thickness is highly adjustable in unlogged and you may logged forest in this Sinharaja Reserve (Stacy, Harischandran, and Gunatilleke, in push). Herbs associated with the variety was smaller than average brush-instance, together with drupes are mainly bird-distributed.
