Download Botanical Inventory of the Lowland Savannas of Belize

Darwin Initiative Project 17-022
Conservation of the Lowland Savannas of Belize
Botanical Inventory of the Lowland
Savannas of Belize
Final Fieldwork Report
Final Fieldwork Report
CONTENTS
1. Introduction….……………………………3
1.1. Background
..……………………...3
1.2 Darwin Project 17-022 .............................3
2. Summary of Activities
........................4
2.1. Field Season 1 ....................................4
2.2. Field Season 2 ....................................6
2.3. Field Season 3 ....................................8
Appendices (in separate document (159 pages):
Appendix 1: Survey site location maps ……………………………………………....1
Appendix 2: Descriptions of survey sites 1-79 ……………………………………….3
Zoë Goodwin (Royal Botanic Garden Edinburgh)
German Lopez (Environmental Research Institute, University of Belize)
The work for this report was sponsored by the Darwin Initiative,
Project 17-022
1. Introduction
1.1. Background
The savannas of Belize occupy almost 10% of the land area, furnishing distinctive
landscapes and a variety of resources. They represent the most northerly example of
tropical lowland savannas in the Americas. These lowland savannas are undervalued
and threatened, yet savannas and associated wetlands provide an extremely important
habitat for plants and wildlife that deserve better recognition and conservation-minded
management.
Despite its national importance for biodiversity as an ecosystem containing many
endemic plants, the savanna remains neglected in comparison with forests in terms of
both botanical and biogeographical research. A key problem is the current inability to
develop a national conservation strategy for this ecosystem. There is still no
comprehensive checklist of savanna species. Information on species distribution is
incomplete, with little yet known about patterns or frequency of endemism. Many
savanna areas, particularly in the south remain unexplored botanically. Thus, there is
no basis for making informed conservation decisions about this biome. And a limited
national capacity for taxonomy was identified in 2005 as a major constraint restricting
Belize from meeting its target under the CBD (vi/9: Global Strategy for Plant
Conservation). Efforts to characterise the biogeography of savannas nationally have
so far been limited. Only the approximate extent of savannas was delimited in the
first Ecosystems Map of Belize of 2001.
Gap analysis in 2005 revealed that, compared to other ecosystems, savannas are
under-represented in the National Protected Areas System. This now needs to be
urgently addressed because savannas are experiencing an increasing variety and
severity of threats. Since it occurs on relatively level ground in close proximity to the
coast and is easily accessible, there is pressure to clear savanna for settlement and for
infrastructure. Despite poor potential for farming, savannas are being converted for
large and small scale agriculture, altering the drainage, nutrient cycling and fire
regimes and resulting in habitat degradation. Since 2005, the Belize Forest
Department (FD) has been seeking to harvest pine and palmetto palms in a sustainable
manner that aspires to protect biodiversity hotspots. FD presently lacks the taxonomic
or geographic information needed to ensure that harvesting does not target areas of
high conservation value within savanna areas. These pressures now make it a priority
to develop a national conservation strategy for savannas.
1.2. Darwin Project 17-022
Darwin Project 17-022, ‘Conservation of the Lowland Savannas of Belize’ main
purpose is to increase available data and enhance the capacity of local institutions to
undertake taxonomic research and mapping, required to identify priority areas for
conservation within lowland savannas of Belize. In response to this urgent need for
information about the biodiversity of the lowland savannas, this project seeks to
strengthen local capacity in taxonomy and vegetation survey.
2. Summary of Activities
2.1. Field Season 1
17 sites were visited during the reconnaissance and nine sites were fully surveyed,
detailed below.
Reconnaissance confirmed that the diverse herbaceous flora is often ephemeral either
because the plants themselves are short lived annuals or because perennial plants such
as grasses and sedges can only be identified during a brief flowering period. Thus it
became clear that multiple site visits during different seasons would be required to
capture the true diversity of a given site.
The geology and soils associated with savannas seemed to vary across the country.
The northern savanna patches, are confined to bands of riverine alluvial and coastal
deposits of sands and gravels overlying the limestone bedrock. Thus in this region
there are areas where broadleaf forest (either as forest thickets or gallery forests)
appears to encroach upon a savanna patch, however the savanna ecosystem seems
unable to extend beyond the alluvial
deposits
onto
the
surrounding
limestone soils. In contrast, the entire
southern coastal plain appears to be
composed of orange-red sands washed
off the Maya Mountain Massiff to the
west. There the mosaic of broadleaf
forest and savanna habitats appears to
be much more fluid. With savanna
encroaching on forest (Meerman pers.
obs.) in some areas and forest
encroaching on savanna in others (Site
16). Presumably fire frequency here
has an important role in influencing the
extent of savanna without the
restriction
of
soils.
Figure 1 Cipura campanulata (Iridaceae) only
flowers at certain times of the year, remaining
dormant underground as a bulb the rest of the
year.
Over 400 vascular plant species were recorded at the sites surveyed, approximately
200 observations and 200 voucher specimens, with an average of 45 species recorded
at each site. A rapid botanical survey of each site was conducted to create a species
list (with DAFOR rankings for each species) and a description of the vegetation
structure and composition. As discussed previously, woody vegetation was relatively
low and cosmopolitan, with most of the diversity in difficult to identify groups such
as grasses (Poaceae) and sedges (Cyperaceae) and small herbs such as Polygala. The
latter groups are often either absent, residing as bulbs underground or hard to spot and
then incredibly difficult to identify sterile. Thus it was proposed that survey sites
should be visited repeatedly to identify the herbaceous flora throughout its seasonal
variations. It was also observed that different types of savanna habitat contained
overlapping flora but of different composition (presumably reflecting local drainage
and fire frequencies).
Figure 2 Eduardo Barrientos (UB) helps survey inundated savanna in Belize District.
For field season 2 the following improvements to the field methodology will be
implemented. A list of all species currently know to be found in the savanna is to be
taken into the field, with room to note in the field at which site each species has been
observed and the abundance of that species (DAFOR). Hard to identify groups such as
Poaceae, Cyperaceae, Asteraceae and Myrtaceae need to continue to be collected to
confirm identity. Ideally every survey site would be visited throughout the year (every
two weeks or so) this is impossible with in the scope of this project, however it is
hoped that many sites can be visited once in the dry season and once in the wet
season.
2.2. Field Season 2
30 new survey sites were visited and five survey sites from field season 1 were
revisited, detailed below. The dry weather in April and May allowed access by vehicle
to several areas of remote savanna, noticeably Deep River Forest Reserve (DRFR)
and Paynes Creek National Park (PCNP) in the Toledo and savanna west of Crooked
Tree Wildlife Sanctuary (CTWS) in Orange Walk. However the early start of the wet
season (16th of May instead of the normal end of May/beginning of June) restricted
access to sites in the Belize and Orange Walk districts later in May and significantly
increased the populations of mosquitos in Corozal district. However all work was
completed as planned successfully with the collection of 453 plant specimens and 595
observation records, an average of 27 records per site.
The first part of the field season focused on the savannas in the Southern districts of
Toledo and Stann Creek. Due to the timing of this field season, late dry season, it was
sometimes problematic in finding suitable survey sites as most areas of savanna in
Stann Creek and Toledo had been burnt recently (within the last two months) or that
were still burning. However for by the dry ground which allowed access to areas of
savanna too remote and wet for most of the year.
In Stann Creek and Toledo sites 2 (Silk
Grass), 3 (South of Independence) and
4 (Swasey-Bladen Forest Reserve)
were revisited. Dense pine woodland
was visited near Kanantik resort,
DRFR and in PCNP, some of these
sites such as those in PCNP had been
burnt recently (2.5 months previously)
with
most
vegetation
showing
significant vegetative regrowth but
little flowering or fruiting; where as
the pine woodland sites in DRFR had a
thick broadleaved understory that had
evidentally not been burnt for a
number of years. More open savanna
grasslands were visited in DRFR,
PCNP, south of Independence and in
Swasey-Bladen
Forest
Reserve
(SBFR), these were mostly recently
burnt (2.5 months previously) however
the recent burns resulted in an
abundance
of
flowering
grasses.
Figure 2. Caterpillar that perfectly mimics a
green snake found on Mandevilla subsagittata
(Apocynaceae) in Deep River Forest Reserve.
After conducting surveys in Toledo and Stann Creek districts work focused on a range
of savanna habitats along the Manatee Highway in Stann Creek and Belize districts
including species rich Oak thicket and wet Cladium jamaicense marshland. In the
northern districts of Belize and Orange Walk a range of open grassland savanna and
Oak thicket savannas were surveyed including savannas west of CTWS which are
characterised by large open areas of white sand and mats of Cladonia lichens. Finally
a series of surveys were conducted throughout a range of marshland, lagoon and
coastal saline savanna habitats in northern Corozal district, close to the village of
Sarteneja.
Figure 3. View north from fire tower of dry season pine savanna in Swasey-Bladen Forest Reserve,
small fire can be seen to centre left of distance.
2.3. Field Season 3
36 new survey sites were visited during October – December 2010. Northern and
central savannas (San Felipe and near Burrell Boom) were visited in late October.
Surveys throughout November and December focused on the savannas in southern
Stann Creek and Toledo. Field work was completed successfully with the collection
of 160 plant specimens and 1485 observation records.
Early on in the field work
season it became obvious
that
the
family
Eriocaulaceae of which
there are six species
endemic to the savannas of
Belize (five only found in
the lowland savannas, one
confined to the Mountain
Pine Ridge, MPR) were
coming into season. This
family had not been
observed in the first two
field seasons. In late
October plants started to
appear
with
immature
Figure 3. Severe erosion in the southern San Felipe savannas
from a vehicle track passing over white sand.
inflorescences, and most
plants seemed to be
flowering by late November through to January. Fertile herbarium specimens are
particularly important to the identification of Eriocaulaceae because the taxonomy of
the group simply to genus level relies on minute floral characters. This means that
field identification of many Eriocaulaceae to genus is nearly impossible. The endemic
species of Eriocaulaceae in Belize are in two genera which are particularly hard to
differentiate (Syngonanthus and Paepalanthus) and are poorly collected; all six
species are known only from three or less specimens each. Thus it was apparent that
herbarium specimens needed to be collected of all Eriocaulaceae observed during the
field work.
The first field trip in late October
involved a day visiting savannas
around the village of Burrell Boom
in Belize district. This area is the
only recorded location of a number
of
endemic
species
of
Eriocaulaceae. Although recent
weather had been dry the ground
was still sufficiently damp that
specimens of Eriocaulaceae could
be collected during the surveying.
Immediately following this 3 days
were spent hiking into the southern
San Felipe savannas (in the Rio
Bravo
Conservation
and
Figure 4. All Pines in Stann Creek; historically a
major focus of botanical collecting.
Management Area) from San Felipe village. Unknown plants and Eriocaulaceae
spotted along the hike in were collected. 5 sites in the north end of the Booth River
marshes and along the length of the San Felipe savanna system were surveyed.
In early November three days were spent surveying twelve sites throughout southern
Deep River Forest Reserve in Toledo, close to the community of Savannah in south
Stann Creek and along the All Pines road in Stann Creek. Again Eriocaulaceae were
observed to be starting to appear in areas of open, damp sand.
In mid November two sites were surveyed at an isolated savanna ridge near the
Mennonite community of Spanish Lookout (Cayo district). This area of savanna is
heavily disturbed by commercial gravel extraction, dumping, logging and probably an
artificially high burn frequency. However in the small patch of surviving savanna a
range of habitats including oak woodland and Eleocharis marshland were observed.
In late November two sites in the
isolated savanna patches near the
village of More Tomorrow in eastern
Cayo were surveyed. These savannas
consisted of extensive pine woodland
savanna with a high herb layer and
palmetto thickets.
A two day survey of twelve sites was
conducted in southern Stann Creek to
the east of the Southern Highway
along the access road to Kanantik and
west of George town. A wide range
of habitats was encountered including
open grassland, dense pine woodland,
Eleocharis marshland, dense oak
woodland and open shrubland.
The last area surveyed was the
isolated savanna at Savannah Bank in
Cayo district. This savanna patch is
located on a ridge of sand and gravel
adjacent to a river flowing directly
from Mountain Pine Ridge (MPR) a Figure 5. Camping in the savanna
few miles upstream. This savanna
had a mix of dense pine woodland savanna and open oak pine savanna grassland and
appeared to be greatly disturbed by human activity. This savanna also uniquely for
other lowland savannas surveyed contained two species of Oak; the common species
of lowland savannas, Quercus oleoides and an additional species Quercus purulhana
which is common in MPR. Both species were equally common in this savanna.