ArticlePDF Available

Abstract and Figures

While fig trees (Ficus: Moraceae) are acknowledged as keystone resources for frugivore communities in tropical forests, their detailed use by frugivores is often poorly understood. In this study, we found over 400 fig trees of 12 species in Amurum Forest Reserve, Nigeria. We analyse bird visits to 12 individual trees of eight Ficus species, observed over a two-year period (2007–9), during which we recorded 3234 visits by 48 bird species. Different fig trees received between 23 and 826 visits during our observations; the diurnal pattern of visits was similar for all fig species, with clear morning (8h00–9h30, larger) and late afternoon (16h00, lesser) peaks, with a lull in visits around mid-day. Mean visit duration varied between 2.9 ± 1.8 min. and 20.5 ± 19.2 min. (mean ± SD) at different fig species. Birds ate between 1.7 ± 1.1 and 5.2 ± 4.4 figs per visit at different fig species. Our study provides preliminary information on Ficus–bird associations and confirms that figs are important resources for frugivorous birds in Amurum Forest Reserve. We suggest that at least four Ficus species provide disproportionately important resources for frugivorous birds: F. lutea, F. ingens, F. thonningii and F. abutilifolia.
Content may be subject to copyright.
2015 1
A preliminary study of bird use of fig Ficus species in
Amurum Forest Reserve, Nigeria
by Barnabas H. DARU1, Kowiyou YESSOUFOU2, Clive NUTTMAN3 & Jacinta ABALAKA4
1Department of Plant Science, University of Pretoria,
Private Bag X20, Hatfield 0028, South Africa. <darunabas@gmail.com>
2Department of Environmental Sciences, University of South Africa, South Africa
3Tropical Biology Association, Department of Zoology, University of Cambridge,
Downing Street, Cambridge CB2 3EJ, U.K.
4A.P. Leventis Ornithological Research Institute, Laminga, P.O. Box 13404 Jos, Nigeria
Received 17 January 2013; revised 14 December 2014.
Summary
While fig trees (Ficus: Moraceae) are acknowledged as keystone resources for
frugivore communities in tropical forests, their detailed use by frugivores is
often poorly understood. In this study, we found over 400 fig trees of 12
species in Amurum Forest Reserve, Nigeria. We analyse bird visits to 12
individual trees of eight Ficus species, observed over a two-year period
(2007–9), during which we recorded 3234 visits by 48 bird species. Different
fig trees received between 23 and 826 visits during our observations; the
diurnal pattern of visits was similar for all fig species, with clear morning
(8h00–9h30, larger) and late afternoon (16h00, lesser) peaks, with a lull in
visits around mid-day. Mean visit duration varied between 2.9 ± 1.8 min. and
20.5 ± 19.2 min. (mean ± SD) at different fig species. Birds ate between 1.7 ±
1.1 and 5.2 ± 4.4 figs per visit at different fig species. Our study provides
preliminary information on Ficus–bird associations and confirms that figs are
important resources for frugivorous birds in Amurum Forest Reserve. We
suggest that at least four Ficus species provide disproportionately important
resources for frugivorous birds: F. lutea, F. ingens, F. thonningii and F.
abutilifolia.
Résumé
Étude préliminaire de la consommation par les oiseaux de figues Ficus
spp. dans la Réserve de la Forêt d’Amurum, Nigeria. Bien que les figuiers
(Ficus: Moraceae) soient reconnus comme étant des ressources-clé pour les
communautés de frugivores dans les forêts tropicales, leur consommation par
les frugivores n’est souvent pas connue avec précision. Dans cette étude, nous
2 B.H. Daru et al. Malimbus 37
avons trouvé plus de 400 figuiers dans la Réserve de la Forêt d’Amurum,
Nigeria. Nous analysons les visites par les oiseaux de 12 arbres appartenant à
huit espèces de Ficus, observées sur une période de deux ans (2007–9), durant
laquelle nous avons noté 3234 visites par 48 espèces d’oiseaux. Les différents
figuiers ont reçu entre 23 et 826 visites pendant nos observations; le scénario
diurne des visites était le même pour toutes les espèces de figuiers, avec des
pics évidents pour le matin (8h00-9h30, le plus important) et la fin d’après-
midi (16h00, moins important), avec une pause dans les visites autour de la
mi-journée. La durée moyenne des visites aux différentes espèces de figuiers
variait entre 2,9 ± 1,8 min. (moyenne ± sdv). Les oiseaux consommaient entre
1,7 ± 1,1 et 5,2 ± 4,4 figues par visite aux différentes espèces de figuiers.
Notre étude fournit de premières informations sur les associations Ficus
oiseaux et confirme que les figues sont des ressources importantes pour les
oiseaux frugivores dans la Réserve de la Forêt d’Amurum. Nous suggérons
qu’au moins quatre espèces de Ficus fournissent des ressources très
importantes pour les oiseaux frugivores: F. lutea, F. ingens, F. thonningii et
F. abutilifolia.
Introduction
Fig trees (Ficus: Moraceae) provide reliable dietary resources for frugivores including
birds in tropical forests (Walker 2007), and birds play important ecological roles
dispersing fig seeds (Peh & Chong 2003), thus contributing to the maintenance of
species diversity (Snow 1981, Wenny & Levey 1998, Holbrook & Smith 2000). Several
criteria have been used to define keystone plant species for frugivores including
phenology (e.g. fructification during periods of general fruit scarcity: White 1994),
reliability of fruit production (Leighton & Leighton 1983, Terborgh 1986), abundance
of fruit produced (Bond 1993, Peres 2000), and most commonly, population size of
frugivores that use specific resources (Peres 2000). Fig trees are well known as a key
component of fruit resources in tropical forests (Lambert & Marshall 1991, Shanahan
et al. 2001, Bleher et al. 2003). Over 10% of the world’s birds and 6% of mammals
consume figs, making Ficus the most widely consumed plant genus (Shanahan et al.
2001). Despite the long interest in mutually beneficial fig-frugivore interactions (e.g.
Wheelwright 1985), most fig-frugivore studies have been restricted to the Neotropics
and southeast Asia, commonly with limited sample size (number of fig species
monitored) and observation period (1–2 weeks) (e.g. Shanahan et al. 2001, Ragusa-
Netto 2002, Bleher et al. 2003, Peh & Chong 2003, Tello 2003). In Africa south of the
Sahara, c. 112 Ficus species are recognised, with southern Africa being the centre of
diversity (Berg & Wiebes 1992); but detailed information on fig-frugivore
interactions is scarce. Long-term research might identify keystone Ficus and frugivore
species to be prioritised in conservation efforts (Bleher et al. 2003).
2015 Bird use of figs 3
We report here a two-year study on birds visits to Ficus species in Amurum
Forest, Nigeria. Amurum holds 278 bird species, 31% of the total recorded in Nigeria,
underpinning its status as an “Important Bird Area” and one of Nigeria’s key avian
biodiversity hotspots (Ezealor 2001) and, therefore, a suitable area to explore fig-bird
interactions. We evaluated visit patterns of birds on eight fig species. Our main
objective was to identify key frugivores visiting Ficus species and potentially guide
future conservation programmes in Nigeria. We expected that visitors to a putatively
critical food resource would mainly visit for foraging. Thus, we assessed the
importance of the various fig species by recording all visits by birds, the time spent by
visitors on each tree and the number of figs eaten; we also noted temporal feeding
patterns and visitor behaviour on the tree.
Methods
The study was conducted in Amurum Forest Reserve at c. 1300 m altitude on the Jos
Plateau in north-central Nigeria (9°52ʹ30ʺN, 8°58ʹ30ʺE). The reserve, which covers c.
300 ha, is a typical savanna woodland dominated by grasses, with scattered rocky
outcrops, and strips of riparian forest along streams (Vickery & Jones 2002). In the
grassland savanna, common trees and shrubs include Dichrostachys cinerea,
Jasminum dichotomum, Combretum fragrans and Piliostigma thoningii. The rocky
outcrops are characterised by Parkia biglobosa, Acacia ataxacantha and several Ficus
species, whereas the most frequent woody plant species in the forest patches are
Boscia angustifolia, Harungana madagascariensis, Syzygium guineense and Ochna
schweinfurthiana (Gofwen 2009). Temperatures in the region are 8–15°C during the
coldest months (November–February) and rise to 30–38°C during the warm and dry
months (March–April). Mean annual rainfall is 1411 mm, falling mainly between
April and October (Payne 1998).
Of the 278 bird species known from Amurum Forest Reserve, at least 58 are, to
varying extents, fruit feeders. We here follow Snow (1971) in using “fruit” to mean
fleshy fruit. Based on Brown et al. (1982), Fry & Keith (2004) and Fry et al. (1988,
2000), we classified these 58 species into three main categories: obligate frugivores
(18 species) that feed primarily on fruit, partial frugivores (28 species) which have,
beside fruits, other major food items (e.g. invertebrates), and opportunistic fruit-eaters
(12 species) that occasionally eat fruit; in this study we recorded 48 of these 58
species (Table 1). Nomenclature of birds follows Borrow & Demey (2001).
We determined Ficus density and diversity in 25 plots of 200 × 200 m (Fig. 1),
selected across the reserve using computer-generated random numbers. In each plot,
Ficus trees were photographed and identified to species level (where possible), the
number of trees of each species was counted, and their geographical coordinates taken,
allowing us to map their spatial distribution. Keay (1989) and the Fig Web
(<www.figweb.org>) were used for species identification.
4 B.H. Daru et al. Malimbus 37
Figure 1. Map of Amurum Forest Reserve showing Ficus species richness. The
Reserve is the diamond-shaped area. Depth of shading reflects interpolated
values of fig species richness from high (dark) to low (light) derived from species
richness in the 25 plots using Ordinary Kriging with a 12-cell neighbourhood.
The 25 plots are indicated and locations of the 12 Ficus trees observed for bird
frugivory are shown. Inset: the reserve’s position in Plateau State and Nigeria.
Over a two-year period March 2007 to June 2009, we observed bird–fig
interactions at 12 individual trees of eight fig species (four trees of F. lutea, two of F.
sycomorus, and one each of F. abutilifolia, F. thonningii, F. ingens, F. ovata, F.
platyphylla and an unidentified Ficus species) when they were found fruiting during
this period (Fig. 2). Each focal tree was found in fruit once during the study period
and observations commenced when the tree was first noted to be fruiting. Hence, we
could not be certain of the overall length (in days) of fruiting period, nor did we
estimate the number of figs produced by each tree during a fruiting event. For all
birds visiting a tree, we recorded the following: species identity and number, time
spent in the tree (including eating, perching and moving within the tree), number of
figs eaten and handling behaviour. Independence of observations was not assured as
birds were not marked:individual birds repeatedly revisiting the same tree would
have been classed as different observations. We acknowledge that this may have
caused pseudo-replication, but judging from observations of different individuals
visiting concurrently, and considering the extended study period, we believe the data
2015 Bird use of figs 5
Figure 2. Chronology of observation of bird-fig interactions in Amurum Forest
Reserve, Nigeria. The perpendicular lines mark first and last observation day for
each tree, and their length is arbitrary to enable legibility. N days in brackets are
total observation days on each tree.
on fruit-feeding behaviour to be reliably indicative of true patterns. Visitation was
recorded by scan-sampling from a concealed position using binoculars and telescope.
Observations consisted of 12 h sessions (6h00–18h00), lasting from the time of
ripening of figs on an individual tree through to consumption of the last figs on it,
following the method of Tello (2003). We collected quantitative data on visit time
(seconds spent on a tree) and fig consumption (number eaten per visit), and also
recorded the temporal patterns of visits and the behaviour of visiting birds.
A preliminary analysis showed that foraging activity of frugivores occurred
mainly between 6h00-11h00 and 13h00-18h00, with lower activity in the afternoon.
We therefore explored the differences between morning (6h00–11h00) and afternoon
(13h00–18h00) in the number of figs eaten, time spent on each tree, and number of
visits to each tree, using the non-parametric two-sample Kolmogorov-Smirnov test.
We also investigated intra-specific differences among individual trees of Ficus lutea
by analysis of variance (ANOVA), contrasting mean time spent per visit, mean
number of figs eaten per visit and number of visits by different bird species, between
individual trees (n = 135, 229, 302, 308 for the four trees; sample sizes are the subsets
of visits where fig consumption was observed) using Tukey’s honest significant
difference (HSD). To assess whether these three variables were correlated, we
calculated the correlation coefficient and determined its significance using Pearson’s
product-moment method. Prior to this correlation test, variables were log10-
transformed to meet the assumptions of normality and homogeneity of variance.
6 B.H. Daru et al. Malimbus 37
Finally, we explored the temporal dynamics of tree usage by frugivores. All analyses
were carried out using R (<http://www.R-project.org> consulted 2013). All mean
values are reported as mean ± 1 standard deviation.
Results
Fig population
We recorded 412 fig trees of 12 species in the 25 sampled plots with more species
recorded in the central parts of the reserve (Fig. 1). Ficus lutea (122 trees), F.
thonningii (96), F. abutilifolia (78), F. ovata (39), F. sycomorus (19) were the most
abundant species, with F. platyphylla, F. ingens and the unidentified species
represented by one tree found each; the four other Ficus species found, at which we
did not make frugivory observations, were F. sur (17 trees), F. umbellata (17), F.
glumosa (13), F. polita (1). The overall density of the combined Ficus population in
the reserve was 1.35 trees/ha.
Visitation to Ficus spp.
We observed 3234 individual bird visits, representing 48 bird species visiting the 12
Ficus trees monitored (Table 1). Ficus lutea received the most bird species (38
species cumulatively for four individuals, which received 11, 17, 28 and 26 species
each: mean species per tree = 20.5), followed by F. abutilifolia (19 species), F.
thonningii and F. sp. (17 species each), F. ingens (15 species), F. ovata (14 species),
F. sycomorus (18 species cumulatively for two individuals, which received 7 and 16
species each: mean species per tree = 11.5) and F. platyphylla (5 species).
More than half of the total number of bird visits (1665) were observed on the four
trees of F. lutea, followed by F. abutilifolia, F. ingens, F. sp. and F. sycomorus, the
three remaining species each receiving < 5% of visits (Table 2).
Behaviour
The majority of bird visitors (> 55%) swallowed figs whole. We also observed birds
perching and occasionally pecking out parts of the figs (29% of visits). The least
frequent behaviour (5% of visits) consisted of birds (three species only, described as
opportunistic frugivores and marked with asterisks in Table 1) eating insects rather
than figs.
Several bird species visited multiple fig species (Table 1). Among the obligate
frugivores, the Common Bulbul and the Yellow-fronted Tinkerbird were recorded on
all eight Ficus species, and the Speckled Mousebird was recorded on seven of them.
Opportunistic and partial frugivores were recorded in up to six species (Table 1).
The longest mean visit times were observed on Ficus ingens, followed by F. ovata
and F. sycomorus (Table 2).
Table 1. The total number of visits by each bird species to the eight Ficus species studied in Amurum Forest Reserve, Nigeria:
Fa, Fi, Fl, Fo, Fp, Fsp, Fsy, Ft correspond to F. abutilifolia, F. ingens, F. lutea, F. ovata, F. platyphylla, F. sp., F. sycomorus and
F. thonningii respectively. The birds’ frugivory category (see Methods) also indicates species that visited but ate only insects
in the trees (marked *) and species that visited but did not eat figs or insects (i.e. perched without appearing to feed, marked †).
Frugivory Visits to Ficus species
category Fa Fi Fl Fo Fp Fsp Fsy Ft
Scopidae
Scopus umbretta Hamerkop opportunistic 0 0 1 0 0 0 0 0
Falconidae
Falco biarmicus Lanner Falcon opportunistic 0 0 1 0 0 0 0 0
Columbidae
Streptopelia hypopyrrha Adamawa Turtle Dove opportunistic 0 0 2 0 0 0 0 0
S. senegalensis Laughing Dove opportunistic 0 0 1 0 0 0 0 0
S. vinacea Vinaceous Dove opportunistic 0 0 1 4 0 0 0 0
Turtur abyssinicus Black-billed Wood Dove opportunistic 0 0 3 0 0 0 0 0
Treron waalia Bruce’s Green Pigeon obligate 1 0 244 0 0 0 0 0
Musophagidae
Musophaga violacea Violet Turaco obligate 41 0 96 0 0 2 0 0
Crinifer piscator Western Grey Plantain-eater obligate 32 0 95 2 0 0 17 1
Cuculidae
Centropus senegalensis Senegal Coucal opportunistic 0 0 0 0 0 0 1 0
Coliidae
Colius striatus Speckled Mousebird obligate 113 189 326 73 0 55 80 5
Meropidae
Merops bulocki Red-throated Bee-eater opportunistic* 0 0 2 0 0 0 0 0
Bucerotidae
Tockus erythrorhynchus Red-billed Hornbill partial 0 0 10 0 0 0 0 1
T. nasutus African Grey Hornbill obligate 4 1 157 0 0 19 9 1
2015 Bird use of figs 7
Frugivory Visits to Ficus species
category Fa Fi Fl Fo Fp Fsp Fsy Ft
Lybiidae
Pogoniulus chrysoconus Yellow-fronted Tinkerbird opportunistic 4 1 3 1 2 1 2 1
Lybius dubius Bearded Barbet obligate 8 4 179 0 0 1 33 23
L. vielloti Vieillot’s Barbet partial 0 0 57 0 0 10 0 7
Picidae
Dendropicos fuscescens Cardinal Woodpecker opportunistic 0 0 4 1 0 2 1 0
Mesopicos goertae Grey Woodpecker opportunistic 0 0 1 0 0 0 0 0
Pycnonotidae
Pycnonotus barbatus Common Bulbul obligate 51 46 62 11 10 48 52 16
Chlorocichla flavicollis Yellow-throated Leaflove obligate 1 4 49 0 0 0 0 4
Turdidae
Turdus pelios African Thrush opportunistic 45 4 41 13 0 12 20 0
Muscicapidae
Myrmecocichla cinnamomeiventris Mocking Chat opportunistic 11 1 6 0 0 23 0 0
Melaenormis edolioides Northern Black Flycatcher opportunistic 0 1 1 0 0 0 0 0
Sylviidae
Eremomela pusilla Senegal Eremomela opportunistic 17 5 4 0 0 1 1 0
Sylvietta brachyura Northern Crombec opportunistic 1 0 0 0 1 0 0 1
Phylloscopus trochilus Willow Warbler opportunistic 0 1 7 0 0 0 0 0
Sylvia borin Garden Warbler opportunistic 6 0 0 0 0 11 0 0
S. communis Common Whitethroat opportunistic 1 25 18 2 0 1 13 0
Cisticolidae
Camaroptera brachyura Grey-backed Camaroptera opportunistic 0 0 5 0 0 0 0 0
Prinia subflava Tawny-flanked Prinia opportunistic 0 9 0 2 0 0 8 3
Platysteiridae
Batis senegalensis Senegal Batis opportunistic 0 0 0 0 0 0 0 2
8 B.H. Daru et al. Malimbus 37
Monarchidae
Elminia longicauda Blue Flycatcher opportunistic* 0 0 1 0 0 0 0 0
Terpsiphone viridis Paradise Flycatcher opportunistic* 0 0 0 0 0 0 0 3
Timaliidae
Turdoides plebejus Brown Babbler opportunistic 0 0 13 0 0 0 1 0
Remizidae
Anthoscopus parvulus Yellow Penduline Tit opportunistic 0 0 0 0 0 0 0 1
Nectariniidae
Chalcomitra senegalensis Scarlet-chested Sunbird opportunistic 4 1 27 3 0 0 15 0
Nectarinia venusta Variable Sunbird opportunistic 0 0 1 1 0 0 0 0
Zosteropidae
Zosterops senegalensis Yellow White-eye partial 0 4 12 2 0 6 22 4
Sturnidae
Onychognathus morio Neumann’s Starling obligate 15 0 1 0 0 0 0 0
Lamprotornis purpureus Purple Glossy Starling obligate 0 0 183 0 1 40 61 0
Cinnyricinclus leucogaster Violet-backed Starling obligate 0 0 25 0 0 0 0 0
Passeridae
Passer griseus Grey-headed Sparrow opportunistic 0 0 0 0 0 0 0 1
Ploceidae
Ploceus heuglini Heuglin’s Masked Weaver opportunistic 0 0 1 0 0 0 0 0
P. cucullatus Village Weaver opportunistic 9 0 0 4 0 0 87 0
Estrildidae
Estrilda caerulescens Lavender Waxbill opportunistic† 31 0 24 1 9 3 1 0
Lagonosticta sanguinodorsalis Rock Firefinch opportunistic† 0 0 1 0 0 1 0 0
L. senegala Red-billed Firefinch opportunistic† 0 0 0 0 0 0 0 1
Total visits 395 296 1665 120 23 236 424 75
Number of species visiting 19 15 38 14 5 17 18 17
2015 Bird use of figs 9
10 B.H. Daru et al. Malimbus 37
Table 2. Summary of Ficus species visited by birds during the study period. Fig
sizes (mm) are reported as mean syconium length (first value) and width (second
value). Habitat types: SW = savanna woodland; GF = gallery forest; RO = rocky
outcrop.
Ficus species Fig size Habitat Total visits Time spent n figs eaten
in mm (n) types per tree per visit (min.) per visit
abutilifolia 22.9 x 12.1 (44) SW 395 9.1 ± 10.9 3.9 ± 5.2
ingens 5.0 x 4.5 (30) SW 296 20.5 ± 19.2 4.8 ± 3.9
lutea 23.1 x 21.7 (80) GF, SW 416.25* 12.2 ± 26.0 3.6 ± 5.5
ovata 27.5 x 28.8 (15) RO 120 15.5 ± 31.7 2.3 ± 1.7
platyphylla 14.0 x 13.1 (16) RO 23 2.9 ± 1.8 1.7 ± 1.1
sp. indet. 20.1 x 18.2 (30) RO 236 6.3 ± 5.6 3.9 ± 5.5
sycomorus 38.5 x 36.1 (23) RO, SW 212* 15.2 ± 17.0 2.9 ± 2.4
thonningii 8.3 x 6.5 (40) RO 75 7.4 ± 5.8 5.2 ± 4.4
*Means of the visit numbers to the four F. lutea (826, 229, 302, 308 visits) and two F.
sycomorus (29, 395 visits) trees observed: sample sizes for behavioural measures are
the “total visits” column, except for F. lutea (n = 1665) and F. sycomorus (n = 424).
We found no strong correlation between mean number of figs consumed per visit
and fig size (maximum dimension) (r = –0.48, P = 0.23, n = 8), although the two
species with the smallest figs, F. ingens and F. thonningii, had the greatest mean
number of figs eaten per visit (Table 2). There was also no significant correlation
between the number of bird species that visited a tree and fig size, nor between total
number of visits to a tree and fig size.
There was a general similarity in the daily pattern of use of the eight fig tree
species by birds (Fig. 3), with most feeding activity occurring from 6h30 to 10h00 and
the morning peak falling roughly between 8h00 and 9h30 (a little later in F.
platyphylla). No visitors were seen on trees between noon and 13h00. There was a
lesser period of activity from around 14h00 to 18h00, with its peak around 16h00
(Fig. 3).
The mean time spent per visit on each tree was similar among the four individuals
of Ficus lutea (Tukey HSD test: P > 0.05; Fig. 4), but the numbers of visits by birds
of different species and mean figs eaten per visit differed significantly between the
four trees, in four and five of the six pairwise combinations, respectively (Tukey HSD
tests, both P < 0.05; Fig. 4).
There was a strong correlation between mean length of visit and mean number of
figs eaten per visit at each fig species (r = 0.57, P < 0.001, n = 8) and significant but
weaker positive relationships between number of visits and mean number of figs eaten
per visit (r = 0.17, P < 0.001, n = 8) and between number of visits and mean duration
of the visit (r = 0.12, P < 0.001, n = 8).
2015 Bird use of figs 11
Figure 3. Daily feeding patterns on eight Ficus species, as the frequency of bird
visits for every hour of the day. Grey bars signify overlap between black and white.
Figure 4. Intra-specific differences in visitation pattern between individuals of
Ficus lutea. The box ends mark the first and third quartiles, the median is
indicated by the horizontal line, the range by the vertical dashed line, and
outliers (points > 1.5 x the interquartile range) by circles. Data points on central
graph are numbers of visitors of different bird species, whereas all species are
grouped for visit times (left) and number of figs eaten (right).
12 B.H. Daru et al. Malimbus 37
Discussion
Differential attractiveness of Ficus species has previously been reported for African
frugivores: for example, Bruce’s Green Pigeon was said to favour Ficus platyphylla
(Morel et al. 1986), although in the present study it was not noted on F. platyphylla but
fed almost exclusively on F. lutea. Plant species that attract a diverse community of
frugivores may similarly be important for frugivore survival (Peres 2000). The relation-
ships observed in our study between birds and fig trees may reflect bird preferences for
certain Ficus species. For example, F. lutea was the most visited fig species (per tree), in
terms of both number of bird species and number of visits. The longest visit durations
were on F. ingens, F. ovata, F. sycomorus and F. lutea, and the most fruits eaten per
visit on F. thonningii, F. ingens, F. abutilifolia and F. sp., respectively. Of the three
most abundant fig species in Amurum, F. lutea, F. abutilifolia and F. thonningii, the
former two received the most visits per tree, whereas F thonningii received relatively
few visits although its small fruits had the highest removal rate (mean figs removed per
mean visit time) of all species (Table 2). The somewhat scarce F. ingens received many
long visits but showed relatively low levels of fruit removal than more common species.
Hence, the drivers of consumption are likely to be factors other than tree density.
Factors driving the usage of a particular fig species might include tree density,
fruiting phenology, fig colour, fig nutritive value and fig size (Korine & Kalko 2000,
Githiru et al. 2002, Herrera 2002, Bleher et al. 2003, Lord 2004). There was great
variation in fig size between the eight Ficus species (Table 2; cf. Berg & Wiebes
1992), which could account for some of the variation in fig species attractiveness. But
although species with small fruits are presumably accessible to a larger range of bird
species, we found no significant relationships between fig size and visit frequency or
number of bird species visiting.
For F. lutea, there were significant differences between the four trees in number
of visitors and mean number of figs eaten per visit, although the numerical difference
in the latter was slight. These intra-species differences indicate that the conclusions on
interspecific differences below, based on only a single tree for most species, must be
treated as preliminary.
There was a general similarity in temporal feeding patterns on all fig species, with
heavy activity in the morning, except that activity on F. platyphylla occurred slightly
later in the morning (but not in the afternoon) compared to other fig species. One
possible reason could be that frugivores prefer the other species and later move onto
F. platyphylla when the fruits that ripened overnight on the other species are depleted.
Supporting this, F. platyphylla had a low number of birds visiting, and the lowest rate
of fruit removal. As such, F. platyphylla may represent a “backup resource” relative
to more preferred species. Choice tests could examine this possibility. The overall
pattern of greatest visitation before 10h00 conforms to a common pattern of avian
foraging and Breitwisch’s (1983) finding at a Ficus in Cameroon.
2015 Bird use of figs 13
Visitation in the morning was nearly three times higher to F. thonningii than to all
other tree species, with a peak slightly later than all other trees except F. platyphylla;
in the evening, the latter part of the afternoon peak in visitation to F. thonningii
occurred when bird activities started declining on other fig trees (Fig. 3). F. thonningii
appears to be an important food resource in Amurum; it is found at high density, and
although visit times are relatively short, the heavy morning usage pattern and high
fruit removal rates (with no figs dropped) suggest it is a preferred food for frugivorous
birds. Bleher et al. (2003) found that F. thonningii provided the most reliable
resources for birds in Oribi Gorge Nature Reserve in South Africa.
Our Ficus trees were utilized by some opportunistic frugivores which foraged for
insects but were not seen to consume figs (Red-throated Bee-eater, Blue Flycatcher,
Paradise Flycatcher). Additionally, a number of birds used focal trees for perching but
not feeding at all, e.g. Hamerkop, Lanner Falcon, Lavender Waxbill, Red-billed
Firefinch, and the Nigerian endemic Rock Firefinch.
Overall, our data on Ficus–bird associations show that figs are important
resources for frugivorous birds in Amurum Forest Reserve. Ficus lutea, F. ingens, F.
thonningii and F. abutilifolia in particular appear to be the most important fig
resources for birds, though we remain cautious in this conclusion because our sample
size was limited. The site harbours a high density of fig trees of a variety of species
that are used by a large and diverse assemblage of visitors. Longer-term research
should focus on the reproductive phenology as well as temporal and spatial
availability of figs. This will help identify critical resources and potential keystone
species that will inform conservation planning. Reforestation programs should not
only consider species rarity and vulnerability but also give priority to plant species
that are especially useful in sustaining bird diversity and ultimately ecosystem
stability.
Acknowledgments
We are grateful to the A.P. Leventis Ornithological Research Institute, Jos, for study
permission and overall support. Thanks to Simon van Noort for assistance with tree
identification and Arin Izang, Useh Damburam and Mary Maisaini for fieldwork. This
work was supported by Rufford Small Grant (U.K.) reference 32.12.07. We thank two
reviewers for their comments on earlier drafts.
References
BERG, C.C. & WIEBES, J.T. (1992) African Fig Trees and Fig Wasps. Koninklijke
Nederlandse Akademie van Wetenschappen, Amsterdam.
14 B.H. Daru et al. Malimbus 37
BLEHER, B., POTGIETER, C.J., JOHNSON, D.N. & BÖHNING-GAESE, K. (2003) The
importance of figs for frugivores in a South African coastal forest. J. trop. Ecol.
19: 375–386.
BOND, W.J. (1993) Keystone species. Pp. 237–253 in SCHULZE, E.D. & MOONEY,
H.A. (eds) Biodiversity and Ecosystem Function. Springer, Berlin.
BORROW, N. & DEMEY, R. (2001) Birds of Western Africa. Christopher Helm, London.
BREITWISCH, R. (1983) Frugivores at a fruiting Ficus vine in a southern Cameroon
tropical wet forest. Biotropica 15: 125–128.
BROWN, L.H., URBAN, E.K. & NEWMAN, K. (eds) (1982) The Birds of Africa, vol 1.
Academic Press, London.
EZEALOR, A.U. (2001) Nigeria. Pp. 673–692 in FISHPOOL, L.D.C. & EVANS, M.I. (eds)
Important Bird Areas in Africa and Associated Islands: Priority Sites for
Conservation, Pisces, Newbury.
FRY, C.H. & KEITH, S. (eds) (2004) The Birds of Africa, vol. 7. Christopher Helm,
London.
FRY, C.H., KEITH, S. & URBAN, E.K. (eds) (1988) The Birds of Africa, vol. 3.
Academic Press, London.
FRY, C.H., KEITH, S. & URBAN, E.K. (eds) (2000) The Birds of Africa, vol. 6.
Academic Press, London.
GITHIRU, M., LENS, L., BENNUN, L.A. & OGOL, C.P.K.O. (2002) Effects of site and
fruit size on the composition of avian frugivore assemblages in a fragmented
Afrotropical forest. Oikos 96: 320–330.
GOFWEN, S.N. (2009) Phytodiversity of Three Habitat Types in Amurum Forest
Reserve, Laminga, Jos East LGA, Plateau State. M.Sc. Dissertation, Abubakar
Tafawa Balewa University, Bauchi.
HERRERA, C.M. (2002) Seed dispersal by vertebrates. Pp. 185–208 in HERRERA, C.M.
& PELLMYR, O. (eds) Plant–Animal Interactions — an Evolutionary Approach.
Blackwell, Oxford.
HOLBROOK, K.M. & SMITH, T.B. (2000) Seed dispersal and movement patterns in two
species of Ceratogymna hornbills in a West African tropical lowland forest.
Oecologia 125: 249–257.
KEAY, R.W.J. (1989) Trees of Nigeria. Clarendon, Oxford.
KORINE, C. & KALKO, E.K.V. (2000) Fruit characteristics and factors affecting fruit
removal in a Panamanian community of strangler figs. Oecologia 123: 560–568.
LAMBERT, F.R. & MARSHALL, A.G. (1991) Keystone characteristics of bird-dispersed
Ficus in a Malaysian lowland rainforest. J. Ecol. 79: 793–809.
LEIGHTON, M. & LEIGHTON, D.R. (1983) Vertebrates responses to fruiting seasonality
within a Bornean rainforest. Pp 181–196 in SUTTON, S.L., WHITMORE, T.C. &
CHADWICK, A.C. (eds) Tropical Rain Forest: Ecology and Management.
Blackwell, Oxford..
LORD, J.M. (2004) Frugivore gape size and the evolution of fruit size and shape in
southern hemisphere floras. Austral Ecol. 29: 430–436.
2015 Bird use of figs 15
MOREL, G.J., MOREL, M.-Y. & FRY, C.H. (1986) Columbidae, pigeons and doves. Pp.
442–497 in URBAN, E.K., FRY, C.H. & KEITH, S.(eds) The Birds of Africa, vol. 2.
Academic Press, London.
PAYNE, R.B. (1998) A new species of firefinch Lagonosticta from northern Nigeria
and its association with the Jos Plateau Indigobird Vidua maryae. Ibis 140: 368–381.
PEH, K.S.H. & CHONG, F.L. (2003) Seed dispersal agents of two Ficus species in a
disturbed tropical forest. Ornithol. Sci. 2: 119–125.
PERES, C.A. (2000) Identifying keystone plant resources in the tropical forests: the
case of gums from Parkia pods. J. trop. Ecol. 16: 287–317.
RAGUSA-NETTO, J. (2002) Fruiting phenology and consumption by birds in Ficus
calyptroceras (Miq.) Miq. (Moraceae). Brazilian J. Biol. 62: 339–346.
SHANAHAN, M., SO, S., COMPTON, S.G. & CORLETT, R. (2001) Fig-eating by vertebrate
frugivores: a global review. Biol. Rev. 76: 529–572.
SNOW, D.W. (1971) Evolutionary aspects of fruit-eating in birds. Ibis 113: 194–202.
SNOW, D.W. (1981) Tropical frugivorous birds and their food plants: a world survey.
Biotropica 13: 1–14.
TELLO, J.G. (2003) Frugivores at a fruiting Ficus in southeastern Peru. J. trop. Ecol.
19: 717–721.
TERBORGH, J. (1986) Keystone plant resources in the tropical forests. Pp. 330–344 in
SOULE, M.E. (ed.) Conservation Biology II. Sinauer, Sunderland MA.
VICKERY, J. & JONES, P.J. (2002) A new ornithological institute in Nigeria. Bull. Afr.
Bird Club 9: 61–62.
WALKER, J.S. (2007) Dietary specialization and fruit availability among frugivorous
birds on Sulawesi. Ibis 149: 345–356.
WENNY, D.G. & LEVEY, D.J. (1998) Directed seed dispersal by bellbirds in a tropical
cloud forest. Proc. Natl. Acad. Sci. U.S.A. 95: 6204–6207.
WHEELWRIGHT, N.T. (1985) Competition for dispersers, and the timing of flowering
and fruiting in a guild of tropical trees. Oikos 44: 465–477.
WHITE, L.J.T. (1994) Patterns of fruit-fall phenology in the Lopé Reserve, Gabon. J.
trop. Ecol. 10: 289–312.
... fruit attract a diverse community of frugivores and provide a reliable diet for frugivore survival (Shananhan et al., 2001;Ronsted et al., 2007;Foster, 2014). The capacity to produce large nutritional fruits all year round, especially in the scarcity of other fruit resources, makes Ficus the most widely consumed plant genus (Shanahan et al., 2001;Bleher et al., 2003;Lomascolo et al., 2010;Daru et al., 2015). Examining fig-frugivore interactions across land-use changes can better understand the long-term effects of anthropogenic impacts on the interactions (Bascompte and Jordano, 2007). ...
... Numerous species of birds and mammals have been recorded visiting Ficus spp. in Africa's different landscapes (Table 1, Supplementary Table S8, Fig. 3). These range from West Africa (Daru et al., 2015) to southern Africa (Basabose, 2002;Bleher et al., 2003;Hart et al., 2013;Bonaccorso et al., 2014;Chibesa and Downs 2017), Central Africa (Kagoro-Rugunda and Hashimoto, 2015), and Eastern Africa (McGrew et al., 1988;Tweheyo and Obua, 2001;Tweheyo and Lye, 2003;Seltzer et al., 2013;Bortolamiol et al., 2014). Most Ficus-frugivore interactions recorded in this review were mostly in forest ecosystems (especially protected areas, National Parks and nature reserves, Supplementary Table S2). ...
... Birds species such as hornbills (Tockus and Bycanistes spp.), turacos (Tauraco and Corythaeola spp.), pigeons (Treron spp.), parrots (Poicephalus spp.), lovebirds (Agapornis spp.), barbets (Tricholaema and Trachyphonus spp.), mousebirds (Colius and Urocolius spp.), orioles (Oriolus spp.), starlings (Cinnyricinclus spp.), bulbuls (Pycnonotus spp.), greenbuls (Andropadus and Phyllastrepus spp.) and thrushes (Turdus spp.), in southern Africa (Bleher et al., 2003;Kemp, 2005;Hart and Downs, 2013;Chibesa and Downs, 2017), East Africa (Kirika et al., 2008) and West Africa (Daru et al., 2015) have been recorded feeding on Ficus spp. fruit (Table 1, Fig. 3, Supplementary Fig. S2, Supplementary Table S8). ...
... We conducted this study in and around the Amurum Forest Reserve (09°53′ N, 08°59′ E; Figure 1), Laminga Jos-East, Plateau State, Nigeria. This Reserve is located within the Guinea savannah ecological zone at an altitude of about 1300 m a.s.l, with a mean annual rainfall of about 1411 mm (Daru et al., 2015;Yilangai et al., 2015). The Reserve is an Important Bird and Biodiversity Area (IBA) with over 350 species of birds including the regional endemics Jos-plateau Indigobird Vidua maryea and Rock Firefinch Lagonosticta sanguinodorsalis (Agaldo, 2019). ...
... The Reserve is an Important Bird and Biodiversity Area (IBA) with over 350 species of birds including the regional endemics Jos-plateau Indigobird Vidua maryea and Rock Firefinch Lagonosticta sanguinodorsalis (Agaldo, 2019). It also serves as a stopover and wintering site for many migrant bird species (Daru et al., 2015). Some economically important trees such as the Pakia biglobosa, Lophira lanceolate, Cannarium spp, Vitex doniana and Khaya senegalensis are also found within and around the reserve (Ezealor, 2002). ...
Article
Full-text available
Conservation decisions for bird diversity in the Afrotropics are often based on ecological studies utilizing diurnal bird species likely owing to difficulties associated with sampling nocturnal birds. It is therefore important to compare the sampling effectiveness of some of the available techniques that can be used in nocturnal bird surveys to guide future long‐term survey efforts. Thus, we compared the sampling effectiveness of point count, acoustic recorder and camera trap for estimating nocturnal bird species richness and also across habitat types. We surveyed 20 points that were spaced at least 500 m apart in November and December 2021 in the Amurum Forest Reserve and its surroundings in Jos‐Nigeria. At each point, we used two camera traps, one at the ground and the other at 2.0 m. We also used one acoustic recorder as well as a 15‐min point count during each survey at each point. We encountered 11 nocturnal bird species, primarily nightjars but also owls. While we did not encounter any species with the camera traps, all 11 species were recorded using the acoustic recorder. All species except for Ketupa lacteaus were recorded in point count. Eight species were recorded in the gallery, seven in rocky and nine in savannah. Species richness and estimation using the acoustic recorder and point count were similar across habitat types. We conclude that either point count or acoustic recorders are useful for nocturnal bird surveys in Afrotropical environments. However, the choice of methods should be based on the research questions as some questions may be better answered by a specific method or even a combination of both.
... Higher plants are a major diet for frugivores especially the avian species in a typical ecosystem (Walker 2007;Jordano 2014;Daru et al., 2015). Such fruit producing trees are therefore seen as an important resource which is sometimes marked and defended by avian species that utilize them. ...
... These birds according to morel et al. were more attracted to Ficus platypylla. Daru et al. (2015) in their study on birds use of Ficus species in Amurum forest Reserve Nigeria reported that frugivorous species such as Bruce's green pigeon fed almost extensively on Ficus lutea. It has been reported that plant species that attract a different community of frugivorous avian species may as well be important for the survival of the birds (Peres, 2000). ...
Article
The flora community which attract a different frugivores may be important to the survival of such frugivores. Relationship between avian biodiversity and fruit producing plants may reflect avian fruit choice or preference. This research was done on avian frugivores fruit choice within the forest cover of Federal College of Forestry, Jos in order to study the species and their activity on fruit-producing plants in the site and to compare encounter rate and diversity of avian frugivores across habitats. Bird species were estimated and 212 individual fruit-eating avian species were counted on 28 species of fruit producing plants during this survey. Mean number of fruiteating birds did not differ significantly in the habitats (F63 = 0.1245, Adjusted R2 = -0.02769, P = 0.8832). The abundance of birds in relation to plant species showed a very high significant difference (2 = 339.55, df = 27, P < 0.001). Shannon weiner diversity of birds calculated showed that the diversity in relation to habitat types showed no significant difference (2= 0.045285, df = 2, P = 0.9776). This habitat should therefore be seen as an important habitat for birds and other wildlife.
... Several factors could be drivers of the visits to and use of fleshy fruited plants in an urban mosaic landscape. These include predator absence, human presence (safety of the frugivores or noise), fruiting phenology, and prolific fruit crops (Korine et al., 2000;Herrera, 2002;Bleher et al., 2003;Daru et al., 2015), although these drivers were not tested in our study. Our results showed the role of fruiting trees such as native Ficus species in maintaining frugivorous faunal communities. ...
... These feeding behaviour differences in our study may lead to differences in their seed dispersal potential, and these findings can guide conservation and management programmes in the urban mosaic landscape. Based on our findings and others (Shanahan et al., 2001;Bleher et al., 2003;Eshiamwata et al., 2006;Kuaraksa et al., 212;Kuaraksa and Elliott, 2013;Daru et al., 2015;Mackay et al., 2018), we recommend native Ficus species trees as species for restoration and reforestation programmes. They are highly recommended for conservation programmes in anthropogenically transformed landscapes. ...
Article
Globally with the human population increase, urban expansion has increased, impacting biodiversity and ecosystem functions. Visitation of fruiting trees by vertebrate frugivores can influence the persistence of fleshy fruited trees and so further maintain frugivore communities in transformed landscapes. Figs (Ficus spp.) have been recognised as keystone plant resources that support diverse frugivorous vertebrate communities. Our main objective was to identify the frugivorous vertebrates visiting fruiting Ficus trees in an urban mosaic landscape of Durban, Ethekwini Municipality, KwaZulu-Natal, South Africa, using camera traps focused on focal fig trees. We quantified the diurnal and nocturnal frugivore visitation rates and levels of interactions. We analysed frugivore visits to 12 individual trees of five Ficus species between 2019 and 2020. During 3888 h, we recorded a total of 4,071 videos from camera traps with 10,016 visits and levels of interactions of three main vertebrate taxa (8958 fruit bat visits, 808 bird visits and 250 monkey visits). These were in five Ficus species (F. burkei, F. lutea, F. natalensis, F. sur and F. sycomorus). Of the bird species visiting, we identified a total of 34 species, but some species were unidentified. We recorded a total of 8958 visits by Wahlberg's epauletted fruit bats Epomophorus wahlbergi, and 250 visits by vervet monkeys Chlorocebus pygerythrus. The latter tended to stay for prolonged periods in the trees feeding. Our data showed the importance of fruiting fig trees for vertebrate frugivores in the urban mosaic landscape. This highlights the conservation implications of figs as keystone resources in the urban mosaic landscape. Our findings support the planting and conservation of native Ficus tree species in transformed urban mosaic landscapes for the persistence of forest species biodiversity.
... These trees inhabit tropical to subtropical zones (Lomáscolo et al. 2010). The Ficus genus includes five major species of dicotyledon plants that are always present in Indo-Australasian and neotropical tropical forests and lowland tropical rainforests (Daru et al. 2015). Ficus spp. is an important food source for frugivorous birds in the tropics, as their fruits provide a source of food after the fruiting seasons of other species end (Bleher et al. 2003). ...
... During 30 days of observation of the three Ficus species, 1,811 birds belonging to 21 families and 43 species were recorded ( Daru et al. (2015) identified 48 bird species, with 12-48 species visiting each tree species. Meanwhile, in the Tengger Mountains of East Java, (Kurnianto et al. 2017) reported 46 bird species visiting one Ficus tree species. ...
Article
Full-text available
Hendrayana Y, Sudiana E, Adhya I, Ismail AY. 2022. Bird diversity in three Ficus species in the Kuningan Lowland Forest, West Java, Indonesia. Biodiversitas 23: 2255-2261. Frugivorous birds are an important group in tropical forests, as they promote a wide diversity of plant species and animal communities via tree seed dispersal. The presence of these avifauna depends on food, such as fruits provided by Ficus spp. This study examined the diversity of birds in three species of fruiting Ficus trees located in a secondary, natural lowland forest in Mount Tilu, Kuningan, West Java, Indonesia. Bird numbers in Ficus benjamina L., Ficus sinuata Thunb., and Ficus kurzii King were determined using the concentration count method. The data were analyzed using the Shannon-Wiener diversity index (H′), evenness index (E), and dominance index (Simpson's D). The results showed diversity index values of H´ = 2.255, E = 0.353, and D = 0.8342 for F. benjamina; H′ = 2.305, E = 0.5014, and D = 0.8376 for F. sinuata; and H′ = 2.305, E = 0.5014, and D = 0.8694 for F. kurzii. The bird species with the highest number of individuals was Pycnonotus simplex Lesson, 1839 (378 individuals, 20.8%), followed by Megalaima australis (Horsfield, 1821) (320, 17.7%), Pericrocotus flammeus (J.R.Forster, 1781) (203, 11.2%), Dicaeum trigonostigma (Scopoli, 1786) (116, 6.4%) and Pycnonotus melanicterus (Gmelin, 1789) (109, 6,01%). By (Horsfield, 1821) knowing the important role of ficus trees as a source of food for various species of birds, this information becomes important and can be used by forest managers to support biodiversity conservation, especially bird conservation.
... Though fruit produces discontinuously, most of the birds prefer as a major diet. Ficus fruit is an important food resource for frugivorous birds (Daru et al. 2015). As the Ficus species provide food resources, these plants also involved for the conservation of avian species, as different ficus speciesis in one zone produce fruits in asynchronous season (Mahanta et al. 2016). ...
Article
Full-text available
The trees like Banyan, Peepal, Pitta carica, etc produce fig fruit. This fruit consists several minerals and also consist several antioxidents. In Ayurveda, the uses of fig fruit described. It improves vitality in man and also stimulates oogenesis in females. Fig fruit is a favourite diet for several frugivorous birds. Though fruit produces discontinuously, most of the birds prefer as a major diet. In this paper, the observational research aimed to explore the influence of fig fruit on frugivorous birds reproductive success.
... Although many researches have been carried out in Amurum Forest Reserve, very little information exist on the aquatic and wet land vegetation of the area. Some of the reports related to vegetation in Amurum Forest Reserve includes: [11] on species diversity and abundance of Fig Wasps in Ficus umbellata and Ficus exasperata, [1] on the important of Figs in conservation efforts, [2] on earthworms, soil nutrients and plant diversity, [4] on factors determining the abundance of Lantana camara, [10] on the phyto-diversity of three habitat types in Amurum Forest, [12]on the use of fig Ficus species by birds and [14] on assessment of Ficus diversity. Nevertheless, Amurum Forest Reserves also harbors many types of aquatic plants and semi aquatics (hygrophytes) that are distributed in the rivers that supports the riparian forest. ...
Article
Full-text available
A preliminary study on the hygrophytic composition in the Amurum Forest Reserve, Laminga Jos was undertaken in September to December 2015 using seven (7) different sampling sites. A total number of 57 species belonging to 38 families were recorded as the hygrophytes from the river flowing through Amurum Forest. The division Angiosperms occurred most with 35 species (25 families), followed by Pteridophyta with 19 species (11 families) while Bryophyta had 3 species (3 families). The Hygrophytes occurred in considerable number in all the sampling sites. This report serves as a foot print to the knowledge of hygrophytes' diversity of Amurum Forest Reserve and also serves as a contribution of biodiversity of the region and country at large.
Article
Full-text available
Ficus spp. belongs to the Moraceae family and is primarily found in tropical lowland rainforests. They exhibit various growth types including hemi-epiphytes, climbers, shrubs, and trees. The Ficus genus plays a vital role as a keystone species as it significantly impacts its microhabitat and serves as the primary food supply for frugivores throughout the year. Arunachal Pradesh, a state in Northeast India, located in the Eastern Himalayas, comprises a diverse range of forests, including deciduous, evergreen, pine, temperate, alpine, and grassland enriched with a variety of flora and fauna. The current study was conducted in Pakke Wildlife Sanctuary, Arunachal Pradesh, to determine the Ficus diversity and associated frugivores. The survey was done using 20m X 20m quadrats (41 nos.), which were randomly placed within the sanctuary. Ficus-dependent frugivore diversity was examined in their fruiting season using either focal or scan animal sampling techniques by direct sighting. A total of 21 Ficus species comprising 482 individuals were recorded, with the highest distribution in the Tipi Range and the lowest in the Pakke Kessang Range. Four habits of Ficus species, large trees, small trees, shrubs and climbers, were documented. There are five sub-genera of Ficus that have been recorded. Ficus semicordata is the most abundant species, while F. religiosa is the least abundant. The frequency percentage of F. benghalensis (46.34%) is the highest, and F. religiosa (2.44%) is the least, while the density of F. auriculata (146.34 ha-1) is the highest, and F. religiosa (2.44 ha-1) has the lowest. The highest level of similarity among Ficus species is observed between the Tipi and Seijosa Range. The figs of Pakke Wildlife Sanctuary are associated with 54 frugivore species out of them 43 avian and 11 mammalian species.
Thesis
Frugivory in tropical forests is a major ecological process, as most tree species rely on frugivores for their dispersion, and numerous animal species used fruits as their principal sources of food. However, frugivory networks between plants and animals in Afrotropical forests are poorly described, and the mechanisms shaping them remain largely unexplored. This PhD thesis addresses a structural approach of the frugivory network, a plant-community approach and a methodological approach using local ecological knowledge and cameras.The first chapter describes the frugivory network of Afrotropical forests, based on a compilation of frugivory interactions from the literature that comprised >10,000 links, between 807 tree and 285 frugivore species. We analysed the network structure with a recent method for ecology, the latent block model that groups species with similar interaction patterns and estimates interaction probabilities among them. Larger frugivores were the main dispersers of most trees and larger and/or low wood density trees were the primary fruit sources of most frugivores. Our findings show the vulnerability of this frugivory network and the fragile integrity of Afrotropical forest composition, as large frugivores are largely threatened by defaunation and large trees by logging.The second chapter focused on the trait variations of tree communities within the Congo Basin forest in relation to frugivory interactions. Our findings showed differences in frugivory traits offered among the floristic type, with Atlantic forests offering larger fruits, while Northern forests presented a greater abundance of smaller fruits with smaller seeds. Moreover, we found that while chimpanzees and calaos interact with the fruits that are more abundant, elephants always consume the largest fruits and seeds offered by the community, while smaller birds consume the smallest fruits and seeds.The third chapter focused on local ecological knowledge on tree-frugivore interactions. We used a common set of trees and frugivores species, to compare information gathered by local people, academic knowledge. Local people had substantial knowledge on tree-frugivore relationships, with 39% of unique interactions. LEK also changed our understanding of the frugivory network, by assigning on average smaller frugivores to tree species and smaller seeded plants to frugivore species.In the chapter four, we used camera traps to monitor tree-frugivore information of the terrestrial frugivore forest community of the Moukalaba-Doudou National Park. We comparison of the records with the LEK and academic dataset, and showed that camera record added more than 30% of new interactions Most of these interactions concerned smaller frugivore like rodents, but also large mammals like elephants and gorillas. These results show the necessity to continue the investigation on tree-frugivore interactions but also to integrate other complementary sources to appreciate the complexity of mutualistic networks.This PhD work gave insight on the different mechanisms governing tree-frugivore interactions, regarding the importance of overlap in distribution areas and match between biological traits. We also highlighted biases concerning the dataset with most studies on emblematic species and certain areas, and concerning the different methods with cameras focus on ground frugivores, and LEK restricted by academic knowledge. These results allowed us to give recommendations to counteract these biases, and increase our knowledge on frugivory interactions. One of the recommendations was to diversify the methods to sample interactions, by collaborating with local people in diverse areas of the Afrotropical forests, or by using arboreal cameras to record smaller frugivores.
Article
Full-text available
Frugivory in tropical forests is a major ecological process as most tree species rely on frugivores to disperse their seeds. However, the underlying mechanisms driving frugivore–plant networks remain understudied. Here, we evaluate the data available on the Afrotropical frugivory network to identify structural properties, as well as assess knowledge gaps. We assembled a database of frugivory interactions from the literature with > 10 000 links, between 807 tree and 285 frugivore species. We analysed the network structure using a block model that groups species with similar interaction patterns and estimates interaction probabilities among them. We investigated the species traits related to this grouping structure. This frugivory network was simplified into 14 tree and 14 frugivore blocks. The block structure depended on the sampling effort among species: Large mammals were better‐studied, while smaller frugivores were the least studied. Species traits related to frugivory were strong predictors of the species composition of blocks and interactions among them. Fruits from larger trees were consumed by most frugivores, and large frugivores had higher probabilities to consume larger fruits. To conclude, this large‐scale frugivory network was mainly structured by species traits involved in frugivory, and as expected by the distribution areas of species, while still being limited by sampling incompleteness.
Article
Full-text available
For many tropical forests a tendency for fruit production to fluctuate seasonally has been established, with pronounced peaks of abundance and periods of fruit scarcity during which a few important resources maintain frugivore communities. However, there is a lack of studies in subtropical forests on community phenology and on the identification of important resources. In this study, community-wide fruit availability and its use by the local frugivore community was investigated in the subtropical coastal dry forest of Oribi Gorge Nature Reserve, South Africa over 13 mo from July 1997 to July 1998. Along 19.5 km of phenology trails, 940 individuals of 96 plant species bearing fleshy fruits were monitored twice per month and fruit-eating animals observed. Although some fruit was available all year round richness of both fruiting species and fruit abundance showed a seasonal pattern with peaks at the end of August to beginning of October (i.e. before the rainy season) and March to May (i.e. after the rainy season). Periods of fruit scarcity were found in July and August (i.e. during the long dry season) and in November and December (i.e. during the rainy season). Fruits of 23 plant species were observed being eaten by 18 species of bird and two of monkey. Highest animal numbers were attracted by Ficusthonningii, a species that fruited asynchronously during most of the year and during periods of fruit scarcity, and provided high overall fruit biomass. The importance of this species as a potential keystone resource for the frugivore community is discussed.
Article
Full-text available
Keystone plants that produce seasonally critical trophic resources comprise one of the main classes of keystone species, yet no studies have attempted to examine the ecological attributes that might help us recognize them and evaluate their importance in species-rich plant assemblages. In this paper the concept of keystone plant resources is reviewed using potential candidates pro- posed in the literature for neotropical forest sites. A poorly known example of a potential keystone resource—the gums produced by mature pods of two emergent tree species (Parkia nitida and P. pendula, Leguminosae: Mimosoideae)—is described for primates and other arboreal vertebrates in Amazonian forests. In particular, the fruiting phenology, tree density, patterns of vertebrate consump- tion, and nutritional quality of Parkia gums in Amazonian terra firme forests are considered. Putative neotropical keystone resources are then divided into four intersecting ecological attributes defining their community-wide importance to vertebrate frugivores: (1) temporal redundancy, (2) degree of consumer specificity, (3) reliability, and (4) abundance. From a vertebrate perspective, keystone plants are here defined as those producing reliable, low-redundancy resources that are consumed by a large proportion of the bird and mammal assemblage with which they coexist. Plant populations proposed to date as keystone species range widely across two of these four variables, which may disqualify most putative taxa (including Parkia spp.) from a more formal definition of keystone resources. Other importance attributes, the context-dependent role, the taxonomic refinement, and removal effects of the keystone plant resource concept as applied to tropical forests are also discussed.
Article
A survey is presented of the plant families and genera recorded in the diet of frugivorous birds in the four main tropical forest regions (tropical America, Africa, southeast Asia, Australasia), a distinction being drawn between fruits eaten by specialized frugivores and those eaten by unspecialized, opportunist frugivores. The characteristics of fruits eaten by the two classes of frugivores are discussed, and available data on their size, composition, and nutritive content are tabulated. Fruits eaten by specialized frugivores are generally large, and have relatively large seeds and high nutritive quality. Of the plant families which have coevolved with frugivorous birds to produce fruits of this kind, three (Lauraceae, Burseraceae, and Palmae) are of outstanding importance. By comparison with the American tropics and Australasia, the forest flora of Africa is poor in plants of these families, and the number of specialized frugivores is also small. The possibility that there was formerly a richer assemblage of specialized frugivores in Africa, now extinct, is briefly discussed.
Article
A fruiting Ficus sp. vine in a southern Cameroon tropical wet forest was monitored for 57.75 hours over a 9-day period in early February 1979 Avian frugivores observed eating figs included one fruit pigeon, four hornbill, and three greenbul species. Two species each of monkeys and squirrels also ate figs. Greenbuls were present at 59 percent of the censuses, fruit pigeons at 12 percent, and hornbills at 11 percent. Mean foraging group sizes for greenbuls, fruit pigeons, and hornbills were 1.7, 2.3, and 2.0, respectively. Greenbuls ate an estimated 17,332 fruits over an 8 day period, fruit pigeons 4769, hornbills 2534, and Greater White-nosed Monkeys 811.
Article
At Kuala Lompat, the guild of 29 species of bird-dispersed Ficus exhibited asynchronous fruiting phenology, with no recurrent annual pattern. Fig crops were available in all 36 months of the study, but whilst medium-sized and small-sized figs were always available, crops of large-fruited (mean fig diameter of >20 mm) bird-dispersed Ficus were scarce, with only c16 fruiting events yr-1 km-2 of forest. Seven Ficus species exhibited fruiting patterns which suggested some seasonality, with significantly more fruitings than expected in the period February-April. This period is before the usual major annual community peak in fruiting, at a time when other fruit resources are relatively scarce. Ficus forms a uniquely important group with the subset of plants with bird-eaten fruit because of their numerical abundance, intra-crown synchrony of fruit ripening, relatively short intervals between fruiting, large crop sizes and intra-population fruiting asynchrony. These characteristics, combined with their availability at times when other fruits are scarce, makes Ficus a most important keystone plant resource. For frugivores to be dependent on figs in South-east Asia they need to be wide-ranging. Frugivorous birds with small home ranges may have to rely on keystone plants other than Ficus during some periods of fruit scarcity. -from Authors
Chapter
Species are conserved because they are rare, endemic, large, attractive, or of economic importance. In this paper, I suggest that some species should also be conserved because they have a disproportionate effect on the persistence of all other species — they are “keystone” species.
Article
Patterns of fruit production were monitored over a 1-year period, from June 1990–May 1991, by counting the numbers of freshly fallen ripe and unripe fruits on five 5-km line transects located within 35 km of one another, in lowland tropical rainforest in the Lopé Reserve, central Gabon. A total of 195 species of fruit were found, representing at least 45 taxonomic families. The majority of fruits came from trees. Fruits were assigned to one of six categories which reflected their dispersal syndrome: succulent, arillate, dehiscent, fleshy pods, wind-dispersed, others. About three-quarters of all species had fruits characteristic of those dispersed by animals. There was a marked seasonal pattern to fruit production, with both the diversity and number of ripe fruits available peaking in January, and lowest immediately before and during the major dry season. The only climatic variable that showed a significant statistical correlation with fruit production was insolation. Candidates for the role of keystone fruit species were identified from species which fruited during the major dry season, and patterns of fruit production compared with other areas.