Recent history plays an important role in the physiology, behavior, an
d ecology of individuals, and in the dynamics of populations and assem
blages of species. In this paper, we examine the impact of history on
the species composition of intertidal reef corals, by comparing simula
tion models that incorporate four different levels of knowledge about
the recent past (over a time scale of 1-27 yr). The models are Markov
or semi-Markov transition probability matrix models, based on rates of
colonization, persistence, and species replacement measured from a lo
ng-term study spanning three decades at Heron Island, Great Barrier Re
ef. Rates of colonization (transitions from free space) varied 20-fold
for different species groups, while mortality (transitions to free sp
ace) ranged fivefold, reflecting a wide range of life histories among
the coral assemblage. Virtually all species groups could undergo recip
rocal transitions (e.g., from A to B, and B to A) in a single time int
erval, indicating the lack of a single competitive dominant that was c
apable of outcompeting all or most other species. Transition probabili
ties changed markedly as a function of history. For most species group
s, the probability of persisting (i.e., ''transitions'' from A to A) i
ncreased with time. Thus, a colony that had occupied space for some ti
me was generally more likely to continue to do so than a new arrival.
This result is consistent with an escape in size for older colonies fr
om mortality agents such as competition and predation. However, three
species groups showed the opposite pattern. Algae, Pocilloporid corals
, and fragile tabular Acroporn showed marked increases in transitions
to free space after 3-5 yr, reflecting a more ephemeral suite of life
history traits. Similarly, free space that had recently been generated
had a higher rate of colonization than substratum that had been unocc
upied for some time. These results falsify a major assumption of stand
ard first-order models, i.e., that transition probabilities are consta
nt, and that history is irrelevant. Although the changes in transition
probabilities as a function of history were often striking, the four
different models we employed show only minor variation in community co
mposition in both transitory and climax (equilibrium) phases. Thus, wh
ile recent history was important in determining transition probabiliti
es, it had little effect on community dynamics and structure in this s
ystem. This discrepancy is due to the rapid turnover of corals and alg
ae on shallow reef crests, where only a small proportion of colonies s
urvive long enough to display effects of history. All models agreed th
at the length of time required for this system to reach an equilibrium
community structure is far longer than the observed interval between
recurrent disturbances from tropical cyclones.