+
+
+
+
+
+
+ Therecent growth of large functional trait data
+ bases has been fuelled by standardized protocols forthe
+ measurement of individual functional traits and intensive
+ efforts to compile trait data(Cornelissen etal. 2003; Chave etal. 2009). Nonetheless, there remains no consensusfor
+ the most appropriate sampling design so that traits can be
+ scaled from the individuals on whom measurements are
+ made to the community or ecosystem levels at which infer-
+ ences are drawn (Swenson etal. 2006,2007,Reich,Wright
+ & Lusk 2007;Kraft,Valencia & Ackerly 2008).
+
+
+
+
+
+
+
+
+
+ However, the fast pace of
+ development of plant trait meta-analyses also suggests that
+ trait acquisition in the field is a factor limiting the growth of
+ plant trait data bases.
+
+
+
+
+
+
+
+
+
+ We measured
+ traits for every individual tree in nine 1-ha plots in tropical
+ lowland rainforest (N = 4709). Each plant was sampled for
+ 10 functional traits related to wood and leaf morphology and
+ ecophysiology. Here, we contrast the trait means and variances
+ obtained with a full sampling strategy with those of
+ other sampling designs used in the recent literature, which we
+ obtain by simulation. We assess the differences in community-
+ level estimates of functional trait means and variances
+ among design types and sampling intensities. We then contrast
+ the relative costs of these designs and discuss the appropriateness
+ of different sampling designs and intensities for
+ different questions and systems.
+
+
+
+
+
+
+
+
+
+
+
+
+ With regard to estimating mean trait values, strategies
+ alternative to BRIDGE were consistently cost-effective. On
+ the other hand, strategies alternative to BRIDGE clearly
+ failed to accurately estimate the variance of trait values. This
+ indicates that in situations where accurate estimation of plotlevel
+ variance is desired, complete censuses are essential.
+
+
+
+
+
+
+
+
+ Isso significa que estudos de característica de história de vida compensam? Ver nos m&m.
+
+
+
+
+
+
+
+
+
+ We suggest that, in these studies,
+ the investment in complete sampling may be worthwhile
+ for at least some traits.
+
+
+
+
+
+
+
+
+ Falar que isso corrobora nossa sugestão de utilizar poucas medidas, mas que elas sejam confiáveis.
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Here, we develop a new approach that links functional attributes
+ of tree species with studies of forest recovery and regional
+ land-use transitions (Chazdon et al. 2007). Grouping species according
+ to their functional attributes or demographic rates provides
+ insight into both applied and theoretical questions, such as selecting
+ species for reforestation programs, assessing ecosystem services, and
+ understanding community assembly processes in tropical forests
+ (Diaz et al. 2007, Kraft et al. 2008).
+
+
+
+
+
+
+
+
+
+ Since we have data on leaf
+ and wood functional traits for only a subset of the species in our
+ study sites, we based our functional type classification on information
+ for a large number of tree species obtained through vegetation
+ monitoring studies.
+
+
+
+
+
+
+
+
+
+
+ Our approach avoided preconceived notions of successional
+ behavior or shade tolerance of tree species by developing an objective
+ and independent classification of functional types based on vegetation
+ monitoring data from permanent sample plots in mature and
+ secondary forests of northeastern Costa Rica (Finegan et al. 1999,
+ Chazdon et al. 2007).We apply an independent, prior classification
+ of 293 tree species from our study region into five functional types, based on two species attributes: canopy strata and diameter growth
+ rates for individuals Z10 cm dbh (Finegan et al. 1999, Salgado-
+ Negret 2007).
+
+
+
+
+
+
+
+
+
+ Our results demonstrate strong linkages between functional
+ types defined by adult height and growth rates of large trees and
+ colonization groups based on the timing of seedling, sapling, and
+ tree recruitment in secondary forests.
+
+
+
+
+
+
+
+
+
+ These results allow us to move beyond earlier conceptual
+ frameworks of tropical forest secondary succession developed
+ by Finegan (1996) and Chazdon (2008) based on subjective groupings,
+ such as pioneers and shade-tolerant species (Swaine &
+ Whitmore 1988).
+
+
+
+
+
+
+
+
+
+ Reproductive traits, such as dispersal mode, pollination mode,
+ and sexual system, were ultimately not useful in delimiting tree
+ functional types for the tree species examined here (Salgado-Negret
+ 2007). Thus, although reproductive traits do vary quantitatively in
+ abundance between secondary and mature forests in our landscape
+ (Chazdon et al. 2003), they do not seem to be important drivers of
+ successional dynamics of trees Z10 cm dbh. For seedlings, however,
+ dispersal mode and seed size are likely to play an important
+ role in community dynamics during succession (Dalling&Hubbell
+ 2002).
+
+
+
+
+
+
+
+
+
+ Our classification of colonization groups defies the traditional
+ dichotomy between ‘late successional’ shade-tolerant and ‘early successional’
+ pioneer species. Many tree species, classified here as
+ regenerating pioneers on the basis of their population structure in
+ secondary forests, are common in both young secondary forest and
+ mature forests in this region (Guariguata et al. 1997), and many are
+ important timber species (Vilchez et al. 2008). These generalists are
+ by far the most abundant species of seedlings and saplings, conferring
+ a high degree of resilience in the wet tropical forests of NE
+ Costa Rica (Norden et al. 2009, Letcher & Chazdon 2009). The
+ high abundance of regenerating pioneers in seedling and sapling
+ size classes clearly shows that species with shade-tolerant seedlings
+ can also recruit as trees early in succession. For these species, early
+ tree colonization enhances seedling and sapling recruitment during
+ the first 20–30 yr of succession, due to local seed rain. Species
+ abundance and size distribution depend strongly on chance colonization
+ events early in succession (Chazdon 2008). Other studies
+ have shown that mature forest species are able to colonize early in
+ succession (Finegan 1996, van Breugel et al. 2007, Franklin & Rey
+ 2007, Ochoa-Gaona et al. 2007), emphasizing the importance of
+ initial floristic composition in the determination of successional
+ pathways and rates of forest regrowth. On the other hand, significant
+ numbers of species in our sites (40% overall and the majority
+ of rare species) colonized only after canopy closure, and these species
+ may not occur as mature individuals until decades after agricultural
+ abandonment.
+
+
+
+
+
+
+
+
+
+ Classifying functional types
+ based on functional traits with low plasticity, such as wood density
+ and seed size, could potentially serve as robust proxies for demographic
+ variables (Poorter et al. 2008, Zhang et al. 2008).
+
+
+
+
+
+
+
+
+
+ CONDIT, R., S. P. HUBBELL, AND R. B. FOSTER. 1996. Assessing the response of
+ plant functional types in tropical forests to climatic change. J. Veg. Sci.
+ 7: 405–416.
+ DALLING, J. S., AND S. P. HUBBELL. 2002. Seed size, growth rate and gap microsite
+ conditions as determinants of recruitment success for pioneer species.
+ J. Ecol. 90: 557–568.
+ FINEGAN, B. 1996. Pattern and process in neotropical secondary forests: The first
+ 100 years of succession. Trends Ecol. Evol. 11: 119–124.
+ POORTER, L., S. J. WRIGHT, H. PAZ, D. D. ACKERLY, R. CONDIT, G.
+ IBARRA-MANRI´QUEZ, K. E. HARMS, J. C. LICONA, M.MARTI´NEZ-RAMOS,
+ S. J. MAZER, H. C. MULLER-LANDAU, M. PEN˜ A-CLAROS, C. O. WEBB,
+ AND I. J. WRIGHT. 2008. Are functional traits good predictors of demographic
+ rates? Evidence from five Neotropical forests. Ecology 89:
+ 1908–1920.
+ ZHANG, Z. D., R. G. ZANG, AND Y. D. QI. 2008. Spatiotemporal patterns and
+ dynamics of species richness and abundance of woody plant functional
+ groups in a tropical forest landscape of Hainan Island, South China.
+ J. Integr. Plant Biol. 50: 547–558.
+
+
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+
+