Post on 15-Apr-2016
description
Monthly Achievement Report
Jalova, June 2015
Increasing the species inventory for the Jalova region of the Tortuguro National park -‐ six new
species recorded in the last three months. Summary
GVI's Jalova research base is located in the southern end of Tortuguero National Park, this is a protected area of secondary forest that prior to 1950 was composed of small farms and plantations. One of the projects that GVI is taking part in is creating a species inventory for the local area where all vertebrate species identified are recorded. As of the 30 of June 2015 there have been 442 different species sighted in the study area, 6 of which were added to the list in the last three months.
Objective
The GVI Jalova base works closely with the governmental Ministry of Environment & Energy (MINAE) for Costa Rica, who inform us about what scientific information is to be collected from within the park, thus determining the projects we undertake. One of the long running projects that we have here is the Incidental Project that has been running since 2010, the main purpose of this project is to create a list (inventory) of species that have been found within the area. This project gives vital information to MINAE which can assist them with management decisions and can also guide them in deciding what further information they may require and possible future projects. The incidental project is fairly simple in that it records all vertebrate species sighted and identified each day. This data is used to compose the species inventory which includes every vertebrate species sighted and identified in the area. This list is being constantly updated and at the end of every quarter (3 months) the number of new species, names and IUCN status are reported to GVI.
Report
When the incidental project first started at Jalova, new species were added fairly rapidly to the growing species inventory; however, over time, as more and more of the commonly found species were added to the inventory, the numbers of new species added each month declined (this was to be expected). The rate at which species are added to the inventory is shown in the graph titled "species accumulation curve" (below) showing the total number of species in the inventory at the beginning of each month. As would be expected, the graph shows an increasing number of species and you can see how at the beginning of the project many species were added each month. After the initial few months the graph starts to level off with smaller numbers of species added each succeeding month. Currently, five years after the beginning of the project, news species are being consistently added to the inventory which can either be because they have always been present (but avoided notice or sightings may not have been good enough to identify them with 100% certainty) or they have moved into the area recently. This last quarter which ran from April to June 2015, we added six new species to the inventory which is similar to
the number of new species added in previous quarters. The new species added to the inventory and recorded in the GVI June 2015 end of quarter stats report included four species of birds; Chestnut-‐headed Oropendola (Psarocolius wagleri), Grey Chested Dove (Leptotila cassini), Crested Eagle (Morphnus guianensis) and the Grey Crowned Yellowthroat (Geothlypis poliocephala); one species of reptile, the Tropical Seep Snake, which is also known as the Costa Rica water snake (Hydromorphus concolor); and one new species of mammal, the Black Myotis bat (Myotis nigricans).
Five of these species are unexceptional in that they are registered in the IUCN red list as `least concern` and have either stable or increasing populations. For a species to be listed as `least concern` it needs to be below the thresholds that would determine it as vulnerable in three different criteria: extent of occurrence (range where it is found) over 20000 km2 with no range decline or severe fragmentation; population trend are stable or decline at a rate less than 30% over ten years or 3 generations; and population size of at least 10 000 adults.
The chestnut-‐headed oropendola, grey chested dove, grey crowned yellowthroat, tropical seep snake and the black myotis bat all have large ranges and most are found in countries throughout Central and upper South America. All of these species have stable populations and a large numbers of individuals therefore are classes as `least concern`. The above species are all expected to be found within the Tortuguero National Park area, as they are lowland dwellers and prefer tropical wet forest and regenerating forest or plantations.
The crested eagle, however, is listed as `near threatened`. An exciting species to have sighted in the area, the crested eagle is sparsely distributed throughout Central and northern South America and there are thought to be only 1,000 to 10,000 individuals remaining in the wild. The population is declining in number, which has lead to its `near threatened` status. These eagles prefer lowland tropical and subtropical forests meaning that Tortuguero National Park is potentially a suitable habitat. One of the dangers facing the crested eagle is hunting/loss of prey species due to human activity; as a result, the crested eagle may be able to thrive in the Tortuguero National Park where hunting is prohibited. So far, we have only had one confirmed sighting of the crested eagle in the national park, and it will be very interesting to see if any further sightings occur.
Megan Brett.
0 100 200 300 400 500
1-‐Jan-‐10
1-‐Ap
r-‐10
1-‐Jul-‐1
0
1-‐Oct-‐10
1-‐Jan-‐11
1-‐Ap
r-‐11
1-‐Jul-‐1
1
1-‐Oct-‐11
1-‐Jan-‐12
1-‐Ap
r-‐12
1-‐Jul-‐1
2
1-‐Oct-‐12
1-‐Jan-‐13
1-‐Ap
r-‐13
1-‐Jul-‐1
3
1-‐Oct-‐13
1-‐Jan-‐14
1-‐Ap
r-‐14
1-‐Jul-‐1
4
1-‐Oct-‐14
1-‐Jan-‐15
1-‐Ap
r-‐15
1-‐Jul-‐1
5
Total spe
cies
Species accumula=on curve