ORCID Profile
0000-0002-2573-1622
Current Organisations
James Cook University
,
University of Florida
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Publisher: MDPI AG
Date: 05-11-2021
DOI: 10.3390/D13110564
Abstract: The Blue-throated Macaw (Ara glaucogularis) is a Critically Endangered species endemic to the Llanos de Moxos ecosystem of Beni, Bolivia. To aid conservation of the northwestern population that utilizes the Barba Azul Nature Reserve during the non-breeding season, we set out to learn the sites where these birds breed using satellite telemetry. We describe preliminary tests conducted on captive birds (at Loro Parque Foundation, Tenerife, Spain) that resulted in choosing Geotrak Parrot Collars, a metal, battery-operated unit that provides data through the Argos satellite system. In September 2019, we tagged three birds in Barba Azul with Geotrak collars, and received migration data for two birds, until battery depletion in November and December 2019. Our two migrant birds were tracked leaving Barba Azul on the same date (27 September), but departed in ergent directions (approximately 90 degrees in separation). They settled in two sites approximately 50–100 km from Barba Azul. Some details of the work are restricted out of conservation concern as the species still faces poaching pressures. Knowing their likely breeding grounds, reserve managers conducted site visits to where the birds were tracked, resulting in the discovery of breeding birds, although no birds still carrying a transmitter were seen then. A single in idual still carrying its collar was spotted 13 August 2021 at Barba Azul. The work suggests that the Blue-throated Macaws of Barba Azul use breeding sites that are scattered across the Llanos de Moxos region, although within the recognized boundaries of the northwestern subpopulation. We conclude that the use of satellite collars is a feasible option for research with the species and could provide further conservation insights.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Wiley
Date: 11-01-2019
DOI: 10.1111/GEB.12875
Publisher: Public Library of Science (PLoS)
Date: 30-06-2010
Publisher: Public Library of Science (PLoS)
Date: 08-04-2021
DOI: 10.1371/JOURNAL.PONE.0250022
Abstract: Populations of migratory waterbirds are facing dramatic declines worldwide due to illegal hunting, habitat loss and climate change. Conservation strategies to reverse these trends are imperative, especially in tropical developing countries, which almost invariably allocate insufficient levels of investment for environmental protection. Here, we compared the effectiveness of sustainable-use Protected Areas (PAs) and Community-based Conservation (CBC) arrangements for the conservation of migratory waterbirds that breed on seasonal riverine sandy beaches in Brazilian Amazonia. We modeled local population responses of four migratory waterbird species on 155 beaches along a ~1,600 km section of a major tributary of the Amazon, as a function of community enforcement, official protection status, human pressure and landscape features. We show that 21 community-protected beaches within the study area host more than 80% of all s led birds. Black Skimmers showed the most dramatic response, with breeding numbers 135-fold larger in CBC arrangements compared to beaches with no official protection status. The same pattern was observed for nesting Large-Billed and Yellow-Billed Terns. For the Near Threatened Orinoco Goose, PA status was the strongest predictor of local population size. These dramatic results demonstrate the value of protected refugia, achieved through the concerted action of participating local communities, to support breeding populations of key waterbird species. This highly-effective and low-cost conservation model can potentially be replicated in other regions of the developing world experiencing increasingly intensive exploitation of riverine natural resources.
Publisher: Wiley
Date: 30-08-2017
DOI: 10.1111/BTP.12488
Publisher: Public Library of Science (PLoS)
Date: 13-01-2016
Publisher: Cambridge University Press (CUP)
Date: 11-1997
DOI: 10.1017/S0266467400011020
Abstract: Inability to age tropical trees has imposed major limitations on the basic and applied science of tropical forests. Here advantage was taken of even-aged stands present in successional chronosequences found on Amazonian Whitewater river meanders to simplify the assumptions needed to estimate tree ages from growth measurements. Growth increments of eight common early successional species were measured in 21 0.5-ha plots evenly distributed over chronosequences from the earliest post-pioneer stage to mature Ficus-Cedrela stands representing approximately the mid-point of primary succession. Increment measurements, based on 4 or 5 y of growth, were arrayed in scatter diagrams against the midpoints of the growth intervals. A loess regression of the points, weighted for the higher mortality of slow-growing in iduals, was then conducted to generate a ‘best estimate lifetime growth trajectory’ (BELGT) of a ‘typical’ in idual surviving to maturity. The BELGT curves were integrated to generate a set of derived curves describing the time required by a ‘typical’ surviving in idual to attain any given size up to the maximum for the species. Predictions of the ages of particular stands were derived from these latter curves and found to agree within 3 to 20% of ages independently estimated from the rate of point bar accretion.
Publisher: Public Library of Science (PLoS)
Date: 04-10-2012
Publisher: Wiley
Date: 16-11-2016
DOI: 10.1111/ECOG.01643
Abstract: Africa has been called the ‘odd man out’ because the hectare‐scale tree ersity of African equatorial forests is lower than that of forests in other parts of the tropics. Low ersity has been attributed to the smaller area of the African forest and a history of drought, fire and contraction. Several facts shed doubt on this interpretation. The current area of the central African forest is roughly 2 million km 2 . Even during periods of Pleistocene contraction, numerous moist refugia remained, including 6 posited for Gabon, a country the size of the U. S. state of Colorado. The gamma‐ ersity of Gabon is high, implying higher alpha ersities. Finally, tree ersities on small islands in the Solomons and Fiji archipelagos are twice those prevalent in Gabonese forests, suggesting that historical contractions may not have been sufficient to reduce ersity to its current level. To place the African situation in perspective, we compared tree stands in Gabon and the Peruvian Amazon. Peruvian forests contained a mean of 618 trees ≥ 10 cm dbh per ha vs 377 for Gabon, or 64% more. Peruvian forests contained relatively more small trees (≥ 10, cm dbh) and many fewer large trees (≥ 20 cm dbh) than Gabonese forests. These structural differences were consistent across 10 Gabonese and 10 Peruvian sites and transcended local gradients in climate and geology, suggesting that they are intrinsic to the two continents. Tree species ersity in Perú is concentrated in the small tree class (≥ 10, cm dbh), whereas it is highest in the larger tree classes in Gabon. Alpha ersity is apparently lower relative to gamma ersity in Africa than it is in Amazonian Perú , implying higher beta ersity. The densities of small plants ( m tall) are similar in Gabonese and Peruvian forests the observed structural differences develop later at the sapling and small tree stages. Explaining the low hectare‐scale ersity of African forests thus reduces to understanding why the density and ersity of small trees is so anomalously low.
Publisher: Springer Science and Business Media LLC
Date: 18-10-2017
Publisher: Wiley
Date: 06-2011
Publisher: Wiley
Date: 25-10-2016
DOI: 10.1111/ECOG.01641
Abstract: The forests of central Africa are distinct from counterpart forests in Amazonia by having fewer trees ≥ 10 cm dbh ha −1 , especially small trees 20 cm dbh, and in having sapling cohorts with less ersity than canopy trees. We tested four hypotheses to investigate whether herbivory, in particular, browsing by forest elephants, could be a factor in these differences. We found that the density of small saplings and ersity of large saplings were inversely associated with local density of elephants. We then tested the hypothesis that steep slopes might serve as refugia from elephant foraging, but found that elephants routinely forage on slopes with an inclination of less than ca 30 deg. Nevertheless, the ersity of small trees (≥ 10 cm, 20 cm dbh) was higher on slopes than on paired level‐ground sites. The incidence of break scars on saplings ≥ 2 cm dbh and 6 cm dbh was greater (107/100 stems) on level ground than on slopes (77/100 stems), although high variability precluded statistical significance. After correcting for background breakage not caused by elephants, an estimated 71% of breaks on level ground and 43% of breaks on slopes were attributable to elephants. Liana loads borne by trees at different sites were highly variable and unrelated to slope. Apparently, disturbances are more critical to liana development than herbivory. Elephants, along with other large mammals such as gorillas, duikers, red river hogs and rodents, appear to act as powerful filters on the tree recruitment process in African forests that still retain intact megafaunal communities.
Publisher: Springer Science and Business Media LLC
Date: 08-11-2021
No related grants have been discovered for Lisa Davenport.