Carrion-Tacuri et al. • PREDATION OF LANTANA CAMARA SEEDS 
339 
during the dry season in the dry lowlands ot Santa 
Cruz Island, and (2) investigate seed dispersal. 
Seed predation, and seedling colonization pattern. 
METHODS 
Study Site .—The Galapagos Islands are 
-960 km west of Ecuador in the Pacific Ocean. 
The vegetation of Galapagos is strongly zoned by 
altitude and aspect with the Dry Zone being most 
extensive, occupying the majority of the lowlands 
•if the archipelago (McMullen 1999. Trueman and 
d’Ozouville 2010). Tw'o distinct seasons can be 
distinguished during the year in the Galapagos 
Trueman and d’Ozouville 2010). The warm 
season (Jan to Jun) is caused by warm ocean 
currents sweeping southward from Central Amer¬ 
ica. Mean daily maximum temperature is 29 C 
and mean daily temperature is between 25 and 
26 C (Ziegler 1995). During this season, the skies 
are normally clear, hut heavy showers are frequent; 
this season is the wettest in the Dry Zone of the 
islands. The cool season (Jul to Dec) is caused by 
(he Humboldt Current, resulting in cooler air 
temperatures (18-26 C) with skies usually over¬ 
cast. A mist layer, known locally as 'gartia', 
frequently occurs at higher elevations, but little 
precipitation occurs in lowlands (Ziegler 1995); 
this season is the driest in the lowlands (Trueman 
and d'Ozouville 2010). 
Our study was conducted in the dry' lowlands 
at 26 m above sea level on Santa Cruz Island 
tOO 19' \\. 00 44'S) near Puerto Ayora. The vege¬ 
tation at the study site was dominated by the native 
tree Bursera graven lens (Burseraceae) (51% rela¬ 
tive cover) and the endemic Galapagos lanlana 
Montana peduncularis) (46% relative cover). The 
relative cover of L. camara was 37% (relative cover 
^as measured by contact every 50 cm along live 
linear transects, each of 30 m). 
Study Species. — L. eanuira is a pantropical 
'pecies inhabiting a wide variety of habitats 
around the world (Sharma et al. 2005). It usually 
colonizes open sunny areas such as degraded 
lands, grasslands, crop edges, abandoned crop 
Helds, and coastal areas or forest edges. It also 
colonizes forests alter disturbances including fire 
Dr logging (Parsons and Cuthbertson 2001). Fruits 
01 L camara are two-secded drupes, 4-8 mm in 
diameter, green and hard when immature, turning 
to shiny purple/black when ripe < Auld and Medd 
1^87, Parsons and Cuthbertson 2001). 
Sampling .—Our study was conducted during 
August and September 2009, when L. camara was 
finishing fruiting and fruit pulp was dry. Bird 
activity was observed from sunrise to midday, as 
preliminary sampling confirmed that most forag¬ 
ing activity was concentrated in this period. We 
conducted 24 hrs of observations on five different 
mornings recording bird species and foraging 
behavior at five individual shrubs of L camara. 
Information on foraging behavior tor each bird 
included: number of infructescences visited, fruits 
consumed per foraging bout, and bird behavior 
after feeding. Birds were identified following 
Swash and Still (2000). 
Fruit productivity ol L. camara in our study site 
was measured for 10 tagged adult plants. The total 
number of infructescences per plant and the total 
number of fruits per infructescence (10 infructes- 
cenccs/plant) were recorded. The area occupied 
by each plant was recorded to calculate fruit 
production/nr. 
Ten other adult plants of the same population 
were lagged to record fruit removal. Twenty 
infructescences of these plants were carefully 
bagged with fine mesh nylon for I month to 
measure fruit fall without external intervention. 
Fruit traps consisting of plastic containers 28 cm 
in diameter and 8 cm deep covered with 1-cm 
metallic wire mesh were placed under the marked 
plants to collect fallen fruits. The mesh prevented 
further predation once the fruit entered the 
container. Ten additional plots (10 X 10 cm) 
were marked on the ground surface near the 
tagged L. camara plants and 25 L. camara fruits 
were placed in each. These were followed during 
I month to measure predation ot fruits on the 
ground. 
Colonization patterns ot L. camara seedlings 
were studied by recording their presence under 10 
adult plants. The percentage of soil covered by 
rocks was also recorded under each adult Lanlana 
plant to investigate the ellect ot substrate at 
colonized sites, especially the effect of rocky 
habitats in seedling establishment. 
Statistical Analysis .—Analyses were conducted 
using SPSS Release 18.0 (SPSS Inc.. Chicago, IL, 
USA). Deviations were calculated as the standard 
error of the mean (SEM). Outlier values were 
identified and discarded following the formula 
(mean ± 2 SD’s). Pearson correlation coefficient 
was used to assess correlation between the 
behavior of birds after feeding on L camara and 
the number of eaten fruits, and between the 
number of seedlings and the percentage of soil 
covered by rock. 
