*Ecological Archives*
E084-018-A1

**Emilio M. Bruna.
2003. Are plant populations in fragmented habitats recruitment limited?
Tests with an Amazonian herb. ***Ecology* 84:932–947.

Appendix A. Calculation of per-individual
fecundity (*F*_{i}) for transition matrices.

Per-individual fecundity (*F*_{i})
was calculated as:
, where *p*_{i} = the probability of flowering by plants in each
stage class in each location, *s* = the number of seeds per fruit, *f*_{i
}= the number of fruits produced per flowering plant, and *g*
= probability of seed germination and seedling establishment. Median fruit
set in annual surveys was not significantly different in 1-ha fragments, 10-ha
fragments, or continuous forest for either of the two survey years (Bruna and
Kress 2002), and there is no evidence that seed set varies systematically with
habitat type or plant size. I therefore set *f*_{i} = 4 (the
median value from 348 fruiting plants recorded during the 1998 and 1999 flowering
seasons) and *s* = 2 (mean seeds per fruit = 1.9 ± 0.02 SE,
median = 2, *n* = 873 fruits) for all calculations of *F*_{i}.
However, annual surveys did reveal substantial variation among plots in the
number of flowering plants (total *n* = 466) and the proportion of plants
in each stage class flowering (Bruna and Kress 2002) , therefore calculations
of *F*_{i} for each demographic plot used the specific values of
*p*_{i} observed in that location (Bruna 2001). Values of
*g* were experimentally derived. Here I briefly describe these experiments.
Detailed descriptions have been published elsewhere (Bruna 1999, 2002).

I planted *H. acuminata *seeds
along five 100-m transects in areas immediately adjacent to the ten demographic
plots established in 1998. Seeds were planted in three experimental treatments
designed to give increasing levels of protection to seeds: directly on the ground
(mimicking natural dispersal and exposure to agents of seedling mortality),
in an open plastic cup (preventing removal of seeds but allowing the accumulation
of leaf litter and soil), and in a cup but covered with a fine mesh (to prevent
all seed predation as well as leaf litter accumulation). I surveyed these
seeds for one year, recording the proportion of seeds germinating and establishing
as seedlings. These experiments were repeated twice: once for the 1998–1999
transition year (*n* = 1668 seeds) and once for the 1999–2000 transition
year (*n* = 1320 seeds). Since I was interested in projecting
under natural conditions of seed germination and seedling establishment, I used
the estimates of germination from the experimental treatment mimicking natural
conditions in all calculations of *F*_{i} (referred to as the “ground”
treatment in Bruna 1999 and Bruna 2001). No direct estimates of seed germination
existed for the three continuous forest sites established in 1999 (CF 4-6),
I therefore used the averages of results from the three other continuous forest
sites.

Literature Cited

Bruna, E. M. 1999. Seed germination
in rainforest fragments. Nature **402**:139.

Bruna, E. M. 2001. Effect of habitat
fragmentation on the reproduction and population dynamics of an Amazonian understory
herb (*Heliconia acuminata*, Heliconiaceae). Thesis. University of California,
Davis, California, USA.

Bruna, E. M. 2002. Effects of forest
fragmentation on *Heliconia acuminata *seedling recruitment in central
Amazonia. Oecologia **132**:235–243.

Bruna, E. M., and W. J. Kress. 2002.
Habitat fragmentation and the demographic structure of an Amazonian understory
herb (*Heliconia acuminata*). Conservation Biology, *in press*.

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