The ecology of tropical forest tree seedlings (Man and the Biosphere Series)

The ecology of tropical forest tree seedlings (Man and the Biosphere Series)

BOOK REVIEWS __. _.__ ~~_._~ Tropical forest: the quest for generality ~_~__ aim-t? and arwnd it chimges Given that the withln certain environr...

224KB Sizes 0 Downloads 70 Views





~~_._~ Tropical forest: the quest for generality


aim-t? and arwnd it chimges

Given that the withln certain environr.lental limits. I think largely passive and Sochaatw process 01 that our ecology would improve by asking questions about certain species d ISPersd leads to seedlings establishing III a --.._-_‘L, s’*es and not looking for presentlywide ranqc 01 subcanovv light cawhtions. it 1.dt certam is not w&sing that &ear; concluding that percewed tooad generalities that we know tree species arevely plastic In their light rewill have weak predictive power. The basic The Ecology of spunses, largely simtlar (certainly most are grawtb and reproduction Tropical Forest Tree Seedlings unkhelytu beniche differentiated). and prob are sha. zd everywhere, but rarely are the (Man and the ably corrvergent in their characteristics over conditions and the histories. Biosphere Series) evolutionary time. I we the same problem with the second edited bx Mi>. Slrarnr Patterns al seedling mor:ality withinand book. Urianselul. askwhether differences in ~tweens~iesareena~oustyvariableand species diversity in tropical ecosystems lead are J poor pred!ctlve guide to canopy cumto changes in ecosystem processes such as vositinn. Survival tot he sapling stage is cergrowth, nutrient cycling and water use: or tainly a precondition. but much else can deput more speclllcally, whether loss in birr Biodiversity and Ecosystem”h;pEc!csgron’tonaturity.~rly diversity afferls fox;: !unr:ionin%The idea Processes in Tropical Forests grotih IS morelikelyto besize-classdensi!yis that tree species can be placed intu ecoindepndnlt. butlaterSrnwthmoredensity physiological and structural groups so that edrred by C.H Orions. R Dine und J H Ctrshmon dependent. and nl course what is measured diversity within and between these groups currently (a-1Uyr typicaily) Is not a strong can be studied. This is not aa easy taskand Springer-Vertag, 1996. guldeto theconditionsof recruitment 01 the / this vohnneshows but the beginnings. There D~tl9R.W hbk (xi + 229 pages) (perhaps 50-2Wyr ago) since conISBN 3 540 592iS X are manygrrups butthese are non-exclusive dllions most likely will have changed and and are artdnged again along continua. For These voIun~es lrit w unsett!ed and not historical events staved a marked and vuncexamvle tree svecies able to cove with WY 1 much enlightened. The lack of current i tuatinr! role. There is also the arow%& re- lowdhusuhork soils mav al& be tolerant progress. I co&d. lies in an unsuccesslul aliz& that light requIreme& aad reofdrought.Not toounexpectedly, the conclusearch for generalities in community ecalof spec~cs lie on cnntinua, and the sin% Ior the moment are that there are few aw.trovical in this case. without the newsprevious classifications ol convenience are reliable and consistem pantropical trends ary and correct thwre!ical lramework Since giving way to a new appreciation of growlh wilh changing species richness and that at neither volume shows an appreciation of andsurvivalof juvenile trees. the level 01 broad groupings (such as shade slc&aSicity and sampling stattistics, unlorPerhaps we have come to expect too tolerant understorey trees) there is much ttmately they take us little further. redlmdnnrv. ~ much lromsyntheticoverviews. Manyof!he The bookedited bySwine demonstrates. chapters lack definite conclusions. FurtherThe &mulatlan of ecological ivloras doesmuch of thecurrent :iteratore in the thoseautharswith s%~peciflcstudies mation at the taxonomic level is not making field of tropical seedling ecology, that there rarely had a clearly-dehned pnenomeno~~ to our understanding (our ability to predlci are lew II any generalizatiurls emerging. The isvestigate or problem to answer. They saw change) any clearer. In the past decade we morestudies done. the more lragmentary is that their Ior& had several species and then havecome to realize that every forest site is our understanding. Take, for example, light tried to eluetdate in which ways their seedunique in the details of its species cnmposiwithin the forest. The varying irradiance m hogs differed to explain complementation tinn, and that reeking generallzaHons at tcw ceived by any one seedling (or part oi it) broad a scale lsnot sensible (or particularly and coexistence. Surely, we have moved on changesthroughthe day. changes as it grows lrom such an approach: we should be more useful). Environmental stochasticity. his(if it does) and changes as the vegetation aware 01 the Rolex of history and chance. tory, regional inlluence and chance factors

more direct


/ ’ phnt processes of




! 1sponses i I 1 / j more. i ~ ! /

3 70


i 1%: Elw”lrr srwnre Ltd Au rig,w *r$cJ*rd dlF,?247,91,fSI~O(L

1 .

in lmost far-

whose brain tsatmos, threetimestargerihan its pr4ecrasora and current compebtors, one who makes cumplcr toots. and wctt be

Ns. Patterns of sume lorm dre ,more lhkely to en)< rL$?when wc Blled the tdsonomy-bused nleasures (I! ‘iversity and “m”e 1” ,untt,una,

lure the hrst Hum .soprens ;Ip,marcd. made fires and lduncbed tnghly rcpresentatlona, art. And as disruss~d ,n swera, chapters.

inRlyreaiized to bcfhc”“errstLny Cdilses

ofsprcies compwitlon


gruups-or gradIents. Large-scatcgcogaphlCalcOrrelateSol primdry”rsec”nda~l”rPst dwersity with the constltwnt prncesscs are realty no subst,tutp lnr I”Lllld r~ptlcaftxt cumpwsons between paired utes in whach one is aiiected (e g. by ioggm!: ur ~meas~on) and thentherancontroi.l‘t~rsestudiesstitt remain very iew and WE need more loggedvw.wprimary ,orcst rescwch. Many basic itteas nre ,I”, Juffalen!!y enpiured One IS that ma species-poor forest the loss 01 P random set of n species would be exuected to he of treater effect than I” a spe&s-rich forest b&use in the former the

Sd5 “1 P”ccstrat


ant, SO”,? 0, ,hr,r

“NA. humans represent a unique cm,xr~.d

lossismorelikety to heaiargecomporwnt uf a iunction. group. It IS not too tntcrcstin~ to know how many species are lost but ratbe, what are their relative abundances In relation to the total dis,rib~tion A large mayority 01 ubiquitously rare species are unlikely to be important: It is the common (snmetime3 dorni~~unt) s,aec,es that determme the ecosystem. We must. therrinrr, considrr which particular species are lost and what special signiiicslce this has ior the site. and then conztruct hypaotheses. based on known ecopbysioiogy mechanisms and processes. about what effects these absences rmsht haveon the forest over !,me.

Everything you wanted to know about human cognitive evolution, but were afraid to ask Handbook of Human Symbolic Evolution



ary throry *r,d phylogcnebc reconstrucbon arc united with those emerging frum ethoiosy and c”~nd,ve science. One of the problems Nith HHSF,IS ,hd, it we burn from a ronference h4d 16 years ago.Thccditorsatate that thevntumestarfrd withafwd

some tup~cs ilntt conceptLit


will necrssardy be left “U, Given what we know about ,he I~~PIIPctual achwements 01 modern humans and the unequivocally infermr achwements of thecurren!setofttvingnonhumanprimates. how did we get irom there to here? Or mure

simply. how do you build B modern human usins the intuitions of classic evolutionary theotyasopposed to. let’ssay. themt”ibons of creation scicncc and thew bag of ~mirawlous mutatmn9 One of the truly spertvcutar da& sets for such rcconstructiw acrnunts COCKS frow tile iossd record. and here. the hammid branch of the wotutionaly hush II dense. In ,tw twst part of HHSE. weare treated to a qoantitatwe synthesis of hnw hL~m~mrt anatomy-iromheadtotoe-~aschanged over the tast 5%findthon years Th?rhansrs are dramabc. with some features [email protected] highly cnntinunw and m~r~mrmrlt sb~fts over time. and others exhibiting murphw logical stasis followed by a step-like fump in structure. Thus. we iind a restructuring of the feet and pelvis. a shit, in the pnsition of the cranium r&we to the spinal cord. and I a whoooine increase in brain volume Of course.ihc;e changes didn’t happen overnight. and what 1s so fascmatmg shout the fossil record is the indication that a great deal of the anatomic.d action relevant to our by A. Lock and CR. Peters minds-and thus our [email protected] for symbolic Clarendon Press. Oxiard, ,996. represen!a:ion -occurred within the past S195 hbk (xxix / 906 pages) two or so mdlion yea?3 fSBN 0 19 8.521517 Fur a tan* tm,e. the early hamlnidr were chimp-like:r;iat~velya~na!!
Forcommun~tyrcnlo~,rspeciaily in the tropics. we need a much better understand. ingofstoehastic processes (e.g. recruitment and murfatity) before we can bet$n ,u make any general and meaningful statements.

men,. Hen,, then. !hc insights from wot~t~on-


but then gew

as new topicsappearetiontirr~cene.hntl its they ack”[email protected] so”,e areas of re.earcb wre la, m”re diffndt to cover because the rmp~ricat data base -was growing at an expn nentiat rate fex. new fossils. moiecutar evidence).Tiay e&o Gate that tile biggest omission was the failure to address c~ttwe as a suttc of symbols. think there are mnr~ im-


pOrtant missions. Let me mention two. First. althoughone 01 the chapters pruwdes asynthwsofworkon brainfatcratization. thereis II” accompanyn,g chapter Indicatmg the behavtornlmanliestatians oisuchasymmetrfes in nor.humans and hwmms. there is a tot of empirical action m this area. Furthermore. there is no clearly articulated argunwnt for

my asymmetries I” tne




why human cognibve luncbon appears so muchmoreasymmet~icthan~notherspecier -both closely and diitan,!y related Second. many Interesting dlsc”;3mns “f c”g”ltl”e evotutionover the past fiveorso tbavr emu& from the marriaqe of evoiutmnarv bioi& and cogmtive so&e - the held df evalut~onarypsychuio~y.Thefocus has been to specify the kinds of domain-specific systems of knowledge that are bkely to be uniouetv human due to the cnarticutar cwfubon&ybressures encount&ed in our hominid past. ‘Though there IF controversy rcgarding the anatamyofmind (e.g. how many modules and why these specific ones) and huw it was constructed durmg homimd idstori and in the developing child. the enterhas ted lo novel pred~ ions and emoiricat findine bcticvc it wilt continw to hu so. and p&haps the next handbook will incorporate some of the [email protected] and thee rebcal iruits. In summary. highly r~