Aims of the Expedition
To assess the conservation status of the entire reserve by mapping and comparing areas completely protected from grazing, heavily grazed areas and an area of intermediate regeneration with particular interest in estimating the total population size of blue-throated macaws, what proportion are using the reserve and how they are utilising it.
Our focus is to assess the impact on biodiversity of reduced grazing pressure/habitat protection. We will conduct comparative surveys of key species and assess differences in overall diversity between RBA north, south & east. The work will allow us to provide Armonia with information on species & community responses to protection and give insight into how expansion of the reserve could affect biodiversity.
Monitoring schemes implemented in previous years for key species will also be continued. Our work will be conducted alongside local Birdlife international partner Association Armonia utilizing local scientists and students to assist us with implementing field methodologies and conducting data collection.
Blue-throated Macaw Survey
This project aims to estimate the size of the population of the critically endangered blue-throated macaw currently using the reserve and compare abundances in RBA north, south and east and differences in habitat use (i.e. for foraging/roost) between the areas. Armonia will be running simultaneous population counts in the rest of the species range so the expedition will contribute significantly to the first ever global population survey of the blue-throated macaw. Stationary point count censuses will be conducted twice a week at 14 points across the reserve. Systematic searches of the reserves forests will also be conducted in order to assess habitat use patterns between RBA north, south & east. Sites found to be used by the species as foraging or roost aggregation sites will be recorded via GPS and mapped.
The abundance, density & distribution of three globally threatened passerines (cock-tailed tyrant, sharp-tailed tyrant & black-masked finch) across the RBA’s grasslands will be monitored. The data will be used to compare species responses to grazing pressure and habitat protection. In total 60 individual line transects of 1.3km shall be carried out across the entire reserve. Along transects the time, species, sex and perpendicular distance of each individual bird encountered will be noted and GPS locations recorded. This will allow distance sampling to estimate species abundances and population densities and will also allow species distributions to be mapped. Comparison of relative densities for each species between grazed land, regenerating land, and protected land will allow estimation of population recovery rates in the absence of heavy grazing.
Nightjar surveys will be carried out in order to assess differences in species diversity and relative abundance of the night birds of the reserve with respect to grazing pressure and habitat protection. Timed night searches will be carried out to locate nightjars by their eye shine. The time, species and perpendicular distance from the transect will be recorded and GPS locations taken for each bird. Birds will also be identified by their call.
In order to establish abundance estimates for key mammal species throughout the reserves camera trapping and line transects will be carried out. Abundance of key species as well as overall diversity between the RBA north, south and east will be compared in order to assess species/community response rates to grazing pressure and habitat protection.
The distribution and abundance of the two species of caiman in the reserve, the black caiman and yacare caiman will be studied in order to determine what effect illegal hunting might have had to the local populations. Caiman will be located by their eye shine and the distance between the eyes will be used to estimate the size of an individual. Any ‘incidental’ data will be noted down and used as well.
Fire Ecology Survey
Transects will begin in the centre of the forest islands and following a bearing, move out through the cerrado into the savannah. Multiple transects will be conducted in each of the 3 survey zones: ungrazed, regenerating and grazed land. Vegetation present within the quadrat will be assessed in regards to its fuel load and relative abundance recorded by a qualified expedition ecologist – Dr. Matt Davies – a grassland specialist used on prior expeditions. Height measurements of the grasses will also be taken to allow structural comparison between survey zones. Results will be used to show the effects of grazing type on savannah plant structure.We aim to establish the response of the savannah plant community to the reduction in grazing/trampling which has resulted from habitat protection with an aim to allow prescribed fired to be applied more safely. This will be achieved via comparative diversity inventories between areas of different degrees of grazing. A qualified Bolivian botanist will assist in species identification using reference collections in Santa Cruz.