Results and discussion
Overall floral diversity
A total of 758 taxa were recorded for the four sites surveyed, of which there were 641
taxa of vascular plants (Appendix 1) and 117 taxa
of non-vascular plants or
bryophytes (Appendix 2). The vascular plants comprised 139 families, 390 genera
and 594 species. 101 taxa could not be determined to species level. The dominant
families were Rubiaceae (58 species), Orchidaceae (43 species) and Euphorbiaceae
(28 species) whilst the most species-rich genera were Psychotria (16 species) in the
Rubiaceae family, Ficus (12 species) in the Moraceae family and Syzygium (11
species) in the Myrtaceae family. In total, there were 539 angiosperms (435 dicots
and 104 monocots), 92 ferns and fern allies and ten gymnosperm taxa. Altogether
539 native species were recorded during the survey, of which 224 are endemic to Fiji.
A total of 94 introduced species or exotics were recorded, of which eight were
recognized invasive species.
The preliminary checklist of the bryophytes comprised 68 mosses and 49 liverworts
identified to the family and genus level. The largest families of mosses were
Calymperaceae (14 species), Dicranaceae (12 species) and Hypnaceae (7 species). The
largest liverwort families were Lejeuneaceae (24 species) and Lepidoziaceae (6
species). A notable find was the rare moss, Bescherelli cryphaeiodes, in the cloud forest
of Mt Delaikoro, previously known only from Mt Voma in Namosi, Viti Levu.
New flora records
There were 207 taxa listed as new records of the areas surveyed. These comprised 90
species of vascular plants whose documented distributions did not include the four
sites surveyed, as well as the 68 species of moss and 49 species of liverworts
collected. Bryophyte work is in its infancy in Fiji, hence the high number of new
records yielded by this initial collection (Konrat pers. comm.).
There were a total of ten taxa considered important due to their rarity, botanical
significance and current distribution. Many of these appear on the IUCN Red List
and are protected under the Convention on International Trade in Endangered
Species of Wild Flora and Fauna (CITES) and Fiji’s Endangered and Protected
Species (EPS) Act.
Agathis macrophylla (Lindl.) Mast.—was recorded in most of the study area at
400–500 m. This indigenous tree podocarp found in the lowland and upland
areas surveyed is currently listed as endangered on the IUCN Red list (Farjon,
2013). It is locally known as dakua makadre and is under threat from logging.
Balaka macrocarpa Burret—an endemic palm in the family Arecaceae, sighted in
the vicinity of Mt. Sorolevu and Savusa area between 200–500 m. It is classified
on the IUCN Red List as critically endangered (Fuller, 1998) and is protected
under the EPS. It is locally referred to as niuniu and is a relatively uncommon
Astronidium inflatum (A.C.Sm.) A. C. Sm—an endemic trees species in the
Melastomaceae family. It is classified as critically endangered on the IUCN Red
List (World Conservation Monitoring Centre, 1998a) and is protected under the
Fiji Endangered and Protected Species (EPS) Act. .
Cynometra falcata A. Gray—an endemic species in the Leguminosae family.
Saplings were observed mostly in the understory of the lowland rainforest on
Mt. Sorolevu. It is classified as being critically endangered on the IUCN Red List
(World Conservation Monitoring Centre, 1998b). Logging activities pose a major
threat to its occurrence.
Spiraeanthemum graeffei Seem.—an endemic tree species in the Cunnoniaceae
family. It is listed as an endangered species on the IUCN Red List (World
Conservation Monitoring Centre, 1998c) and is protected under the EPS. Its
biggest threat is from logging.
Storckiella vitiensis Seem.—an endemic species in the Leguminosae family. It is
categorised as a vulnerable species on the IUCN Red list (World Conservation
Monitoring Centre, 1998d) and is protected under the Fiji EPS Act. Major threats
are unsustainable logging activities.
Weinmannia exigua A.C.Sm.—an endemic tree species in the Cunnoniaceae
family. It is listed as critically endangered on the IUCN Red List (World
Conservation Monitoring Centre, 1998e) and has protection under the EPS.
Logging activities pose a major threat to its occurrence.
Seem.—an endemic tree species in the Cunnoniaceae family.
It is listed as a vulnerable species on the IUCN Red list (World Conservation
Monitoring Centre, 1998f) and is protected under the Fiji EPS Act. Logging
activities pose a major threat to its occurrence.
(H.Wendl.) H.Wendl.ex Hook.f.—very few trees were
observed along the river embankments in the lower Waivuvu River catchment.
The palm is endemic to Fiji and is locally common on south east Viti Levu and
Vanua Levu. The palm is locally referred to as soga. Unfortunately the palm is
highly threatened both for the use of the palm heart for food and leaves for
thatching in the tourism industry. Its habitat (swamp) is targeted for land
reclamation both for agricultural development and human habitation.
(Mull.Hal.) M. Fleisch.—an uncommon moss collected on
tree branches near the road in the cloud forest of Mt. Delaikoro at about 1110 m.
The only other known collection has been from Mt. Voma (Namosi Province,
Viti Levu) at 700 m in 2007-2008.
Of the nine principal vegetation types recorded for Fiji, five were encountered in the
study area: lowland rainforest, upland rainforest, cloud forest, dry forest and
talasiga grassland. The dry forest referred to here is a mesic forest. Representative
areas of lowland and cloud forest vegetation types were quantitatively assessed,
whilst the other vegetation types were qualitatively described.
The detailed results of the quantitative assessment of plots in these different
vegetation types are given in Appendix 3. In total, 50 plots along seven transects
were analysed, 36 in lowland forest and fourteen in cloud forest. Within each of
these vegetation types the plots were distributed over a variety of forest habitats
based on the most prominent physical features i.e. ridge flat
, slope or riparian flat.
Lowland rainforest in Fiji is typically found on the windward side of the large
islands, from sea level to 650 m, with an annual rainfall of over 2000 mm. In the
proposed Greater Delaikoro Area the lowland rainforest is found at elevations of 300
m and above, including the upper catchments of the Labasa, Tabia, Qawa, Dreketi,
Koroalau, Nasekau and Qaloyago rivers. Overall, the forest in this principal
vegetation type is best described as primary forest. The majority of the tree species
recorded from the lowland forest plots were either endemic or indigenous. A few
were species associated with human habitation, and some of these were also
observed outside the plots. Stocking of good quality timber tree species was high
and so was the size of merchantable tree species.
Two different lowland forest types were observed and quantified using seventeen
plots in three transects:
Ridge-top forest type
The nine plots used to assess this forest type contained an average of nineteen trees
(range: 14–24) and an average of thirteen species (range: 10–16) per plot. The most
common species was Myristica
(kaudamu), which was present in 50% of the
plots assessed. The largest trees measured were Degeneria vitiensis
(vavaloa) with a
dbh of 82 cm, followed by Myristica
spp. with a dbh of 81 cm and Endospermum
(kauvula) with a dbh of 80 cm. The average tree dbh was 19 cm (range
5–82 cm). Overall, the dominant species for this forest type was Syzygium
38% relative dominance which together with Myristica
spp. makes up two thirds
(66%) of the total tree biomass in the plots.
Slope forest type
A total of 26 plots along four transects were assessed in lowland slope forest at
Navakuro, Nukubolu and Savusa. At Navakuro the most common tree species
recorded were Macaranga
spp. (gadoa), Cyathea
spp. (balabala) and Gironniera
(sisisi). The largest trees were Alphitonia
spp. (doi), Dysoxylum richii
(tarawau kei rakaka)
and Endospermum macrophyllum
with average dbh of 11 cm
(range: 5–55 cm). These more common trees are usually associated with secondary
forest and the larger trees are fast growing trees.
At Nukubolu and Savusa, the 21 plots assessed had an average of nineteen trees
(range: 7–29) per plot, and an average of eleven species (range: 5–17). Syzygium
(yasiyasi) and Gironniera celtidifolia
occurred in more than 30% of the plots assessed,
and were the most common species. The average dbh was 15 cm (range: 5–73 cm).
The largest trees documented in the plots were Calophyllum vitiense
dbh of 73 cm, followed by Retrophyllum vitiense
with a dbh of 68 cm
and Heritiera ornithocephala
(rogi or rosarosa) with a dbh of 65cm and Myristica spp.
with 62 cm. There was no single dominant species as the tree sizes were evenly
distributed amongst all species, but the combined biomass (as reflected in the dbh)
gave a relative dominance of 54%.
In the Greater Delaikoro Area, cloud forest is restricted to mountain tops and ridges
above 850 m and is almost always shrouded in clouds. Precipitation is high and
temperatures are lower than the lowland areas. Trees in the cloud forest tend to be
stunted and heavily covered with bryophytes. Cloud forest vegetation was assessed
in eleven plots at Mt. Delaikoro and four plots at Mt Sorolevu.
An average of 22 trees per plot (range: 13–39) with an average number of thirteeen
species per plot (range: 10–17) was recorded for the area. The most common species
spp. and Cyathea
spp. occurring in thirteen of the fifteen plots
assessed. The average dbh was 7 cm (range 5–22 cm) and the average bole height
was 3 m (range: 1–6 m). The largest tree, with a dbh of 22 cm, was Elaeocarpus
(kabi). Other large trees included Syzygium
spp., Agathis macrophylla
spp. (bo), Litsea
(lidi) and Saurauia rubicunda
overall dominant species was Syzygium
with a relative dominance of 49%.
Other species observed outside the plots that are typical of cloud forest vegetation
spp. (vuga), Polyscias corticata
(danidani), P. joskei
, Physokentia thurstonii
(niuniu), Clinostigma exorrhizum
Three other principal vegetation types, the upland forest, the dry forest and the
talasiga vegetation types were not quantitatively assessed due to time and logistical
constraints. A summary of observations made of these vegetation types is given
Segments of upland forest were observed along the dirt road to the top of Mt.
Delaikoro and along the track (unused logging road) to Mt. Sorolevu from Navakuro
village at elevations around 700m. At Delaikoro some of this forest type has been
planted with mahogany. Some of the more common tree species observed in these
upland forests included Physokentia thurstonii
spp. (sole), Elaeocarpus
spp., Agathis macrophylla, Dacrydium nidulum
(yaka), Retrophyllum vitiense
and Dacrycarpus imbricatus
Most of the native dry forest vegetation type on the leeward side of the Greater
Delaikoro Area has been almost completely destroyed by a combination of grazing,
agriculture activities and fire. Remnants of this forest type may be observed north-
east of Mt. Delaikoro on the upper tributaries of the Labasa and Wailevu rivers.
The grassland is restricted to the slopes and ridge tops and is mostly made up of
(mission grass), Sporobolus
spp. (wire grass), Dicranopteris
spp., (qato or bracken ferns), Pteridium esculentum, Miscanthus floridulus
reed), Dodonaea viscosa
(usi), Casuarina equisetifolia
(nokonoko) and many other
smaller weedy plants. The general lack of tree cover is characteristic of such a
landscape. The grassland is regularly set on fire to allow for
regrowth of grass for
use as fodder for cattle and horses. Most of the lower elevation vegetation
encountered en route to Mt. Delaikoro is made up of this vegetation type and a
typical plant associated with this on Vanua Levu is Cycas seemannii
Woody shrubland habitat type
This vegetation was observed growing between the grassland and the forest edge
and is also referred to as savannah grassland. The area was dominated by secondary
pioneer plant species like Commersonia bartramia
(sama), Parasponia andersonii
(vakaceredavui), Trema orientalis
, Dillenia biflora
(nuqanuqa) and larger patches of Schizostachyyum glaucifolium
(bitu wai) and Miscanthus floridulus
. Also present here are exotic species like Albizia
(raintree, vaivai), Spathodea campanulata
(African tulip), Aleurites moluccana
(lauci), Merremia peltata
and Piper aduncum
(onalulu). This habitat is where active
agricultural activities are occurring both at the subsistence level and on a semi-
commercial scale. Gardens or plantations of Piper methysticum
(yaqona), Musa nana
(banana) and Colocasia esculenta
(taro) are common and so are patches of abandoned
(fallow) gardens. Such activity expands the grassland habitat types into forested
areas and as noticed from the survey will continue to do so especially with
increasing pressure from subsistence farming and a growing population.
River bank/riparian habitat type
The vegetation along the creeks and river systems adjacent to the grassland was
dominated by introduced and native fruit trees. Also found here were important
trees species that have cultural uses, such as Inocarpus fagifer
(ivi, chestnut), Pometia
(dawa), several species of Citrus
spp., Artocarpus altilis
(uto, breadfruit), Cocos
(niu), Codiaeum variegatum
(sacasaca), Syzygium malaccense
(tavola). Other culturally important trees include Aleurites
, Bischofia javanica
(koka), Cananga odorata
(makosoi), Cordyline fruticosa
(qai) and Euodia hortensis
Intact riparian systems were observed further upstream along creeks and streams.
Here large indigenous tree species such as Sterculia vitiensis (waciwaci), Neonauclea
fosteri (vacea), Citronella vitiensis (nuqa) and Calophyllum cf. neo-ebudicum (damanu
dilo) were observed to be the dominant trees forming, in most cases, a closed canopy
over the streams. Bryophytes on rock surfaces and over lower branches of trees were
plentiful, and ground cover species of terrestrial ferns, Selaginella spp. and
herbaceous urticales were common.
The key findings obtained demonstrate that the surveyed areas on Vanua Levu have
high botanical prospects for both future work and research. With the unexpected
high number of floristic datasets, new range extensions, scientifically important
plants but more importantly the high list of indeterminants attained, a follow up or
continued work with longer period in the centres and surrounding vicinities of the
areas must be considered and adopted before making any conclusive statements.
The new range extension of 207 species shows the lack of detailed floristic work on
Vanua Levu especially in botanical hot spots such as the Greater Delaikoro Area.
High altitude (> 600 m) forest systems to the south-east of Mt. Sorolevu and Waisali
should be revisited and more time spent botanizing because some species known
only from their type localities were not assessed during this trip due to time
constraints and adverse weather conditions.
Seasonality was also indicated as an important factor to consider for future surveys,
to ensure that flowering and fruiting collections can aid in the full identification of
specimens to the lowest possible taxonomic level.
The first recorded entomological surveys conducted on Vanua Levu were in 1938 by
E. C. Zimmerman from the Bishop Museum, Hawaii. In 2005 and 2006, the National
Science Foundation (NSF) funded the Fiji Arthropod Survey which included the
island of Vanua Levu (Evenhuis and Bickel, 2005). In 2006 and 2008, Van Gossum
and colleagues also visited the island of Vanua Levu focusing on the species
diversity of the Fijian Zygoptera (Van Gossum et al., 2006; Van Gossum et al., 2008)
In 2009, the Darwin Initiative funded a project titled Insect Inventories in Fiji, focusing
on entomological surveys and included selected sites within Vanua Levu.
In September 2013, a baseline survey was carried out with the primary aim of
determining the general diversity of insects within the areas of Delaikoro, Sorolevu
and Waisali forest. The survey targeted a diversity of habitats (slopes, flats, ridges
and riparian areas) and vegetation types (lowland and upland systems within
primary, secondary and native forests). A variety of collection techniques (light
traps, leaf litter sampling, active and opportunistic surveys) were employed. The
general diversity of insects and those species of higher conservation value (i.e. focal
species) were sampled as an indicator of the status or health of the forest within the
Greater Delaikoro Area.
Site selection and habitat considerations
A number of key habitat types were surveyed (Figure 4) to maximise the chance of
encountering individuals of focal species as well as to adequately sample the
diversity of insects. The location of each survey site is provided in Appendix 5.
Lowland forest areas: targeted specifically to find Fiji’s rare endemic
butterflies Papilio schmeltzi and Hypolimnas inopinata.
Upland forest areas: leaf litter sampling and light traps on slopes mainly
targeted the general diversity of insects within this specific habitat. Active
and opportunistic searches for the endemic phasmids (stick insects or
mimimata) were also conducted.
Ridges: leaf litter sampling and light traps on ridges targeted the general
diversity of insects found within this specific habitat. A high diversity of
insects (and in particular the focal order Coleoptera and the macromoths) is
indicative of intact forest systems.
Riparian surveys in all vegetation types: These surveys specifically targeted
butterflies (namely Fiji’s rare endemic butterfly, H. inopinata) and damselflies
(namely those of the endemic genus Nesobasis). These often fly out to open
areas on a fine day in search for sunlight and food, and usually aggregate
along the streams in forested areas. Their presence, abundance and richness
are excellent indicators of forest and stream systems in good health.
Nocturnal surveys were conducted
using ultra violet (UV) light traps at the
four sites (Figure 3). These were set up
and left to run for 12 hour periods from
6pm-6am (roughly dusk till dawn).