Population genetics of the endangered Wattled Curassow (Crax globulosa,Cracidae, Aves) of the Colombian–Peruvian Amazon using DNA microsatellites and ND2 mitochondrial sequences

The Wattled Curassow (Crax globulosa, Cracidae, Aves) is a large bird living in the Western Amazon basin and a critically endangered species in the Colombian and in the Peruvian Amazon. We carried out the first population genetics analysis of this species employing six nuclear microsatellite markers and sequences of the mtND2 gene. The main results are as follows. (1) The levels of gene diversity were high for the overall population as well as for each of the three islands for both microsatellites and mtDNA. (2) A small amount of genetic differentiation among populations was found with both types of markers (F_ST = 0.027 for microsatellites and N_ST = 0.17 for mitochondrial sequences). (3) Using microsatellites, the Geneclass 2.0 software detected a low correct assignment of individuals to their respective populations. The Structure software only detected one gene pool for the entire area studied. These results are relevant for conservation efforts of this critically endangered species.     

Wattled Curassows in Bolivia: abundance,habitat use,and conservation status

ABSTRACT The Wattled Curassow (Crax globulosa) is a globally threatened species restricted to humid várzea forest (seasonally flooded forest along white‐water rivers) in low‐lying regions of Amazonia. The Wattled Curassow were thought to have been extirpated from the Beni area of Bolivia, but were rediscovered near the Río Negro River in 2001. Our objectives were to determine the size of this population, examine habitat use, and based on our results, assess the conservation status of the Wattled Curassow. During July and August 2006, we used distance sampling to estimate the population density in our study area. We estimated the density of Wattled Curassows at 3.4 (95% CI: 1.4–8.1) individuals/km² and all were observed within 300 m of the river. Based on the availability of suitable habitat (18 km² of riparian várzea habitat within 300 m of the river), we estimated that the breeding population of Wattled Curassows in our study area consisted of 61 individuals. The specialized habitat requirements of the Wattled Curassow has important conservation implications because previous population estimates were based on the availability of várzea forest rather than the availability of water edge habitat within várzea forest. As a result, the current global population estimate (2500–9999) is higher than our estimate (500–2500) that takes the specialized habitat requirements of the Wattled Curassow into account. Given this low estimated population, along with the severely fragmented state of the few remaining populations and their dependence on a specialized and vulnerable habitat, we recommend that the status of the Wattled Curassow be upgraded from Vulnerable to Endangered.     

Predicted population trends for Cozumel Curassows (Crax rubra griscomi): empirical evidence and predictive models in the face of climate change

ABSTRACT We assessed the current conservation status and population trends of Cozumel Curassows (Crax rubra griscomi), a critically endangered and endemic cracid of Cozumel Island, Mexico. Distance sampling was used to estimate the population size in 2005 and compare it with a previous estimate in 1995. Population viability analysis (PVA) was used to model population trends, considering ecological and environmental conditions prevailing in 1995 and 2005. Additional PVA models were constructed using different hypothetical scenarios to assess the effects of particular factors and management strategies on population trends. We estimated a population size of 372 ± 155 curassows in the island's tropical semideciduous forest, before two hurricanes hit Cozumel Island in 2005. PVA modeling predicted a steep decline in population size in the ensuing decades as a result of an increased frequency and intensity of hurricanes related to global climate change, and an observed female bias in the sex ratio likely caused by a higher mortality rate for adult males. We recommend urgent management actions for the long‐term conservation of Cozumel Curassows, including a ban on hunting, eradication of the feral fauna, particularly dogs, and implementation of a captive‐breeding program to supplement the wild population.     

Habitat use and ecology of Wattled Curassows on islands in the lower Caquetá River,Colombia

ABSTRACT Despite being endangered, little is known about the natural history and habitat use of Wattled Curassows (Crax globulosa). From September 2008 to March 2009, we examined habitat associations of this species on three islands in the lower Caquetá River, Colombia. Observations of curassows were made during line‐transect walks, and habitat variables were measured at points where curassows were and were not observed along those transects to assess potential habitat preferences. A total of 182 sightings yielded encounter rates ranging from 0.1 to 0.89 observations/km across transects. Curassows were more likely to be observed close to the river and to lakes on the islands. Additionally, the importance of the river increased as the distance to internal water sources increased. Other habitat characteristics, including tree density, tree diameter, understory density, and canopy cover, did not differ between areas where Wattled Curassows were and were not observed. Flock size ranged from 1 to 9 individuals; most solitary individuals were males and flocks (>2 individuals) generally consisted of more females than males. The association of Wattled Curassows with water sources during the low‐water season may have conservation implications because it could increase their vulnerability to anthropogenic activities such as agricultural activities, fishing, and hunting. As a result, conservation of these curassows on islands in the lower Caquetá River will likely depend on local support.