Why is the Red Uakari Population Declining in the Peruvian Amazon? A study on the Peruvian uakari ecology in the larger Amazonian conservation context Quyen Nguyen Image Source: Arkive.org Abstract: The bald uakari (Cacajao calvus) is a type of New World monkey found in flooded or wooded forests in Amazonian Brazil and Peru whose population is being threatened by various adverse human activities in Peru’s rainforests. This paper explores a few of what those detrimental human activities are and examines the role of local communities in protecting bald uakaris and preserving the larger Amazonian biodiversity. Introduction/Background: The Amazonian Ecosystem Amazonia, especially the western portions at the foothills of the Andes, “stands out as the largest and richest of the wilderness areas” (MacQuarrie 2001: 18), which means good and bad news. The good news is that Amazonia still as the lungs of the earth with at least “40,000 plants, of which 30,000 are endemic” (MacQuarrie 2001: 18), and it is home to at least “1,120 birds (141 endemic), 356 mammals (210 endemic), 338 reptiles (at least 66 endemic), and 410 amphibians (326 endemic)” (MacQuarrie 2001: 19) which concentrate particularly in the western edges of the massive forest. Unfortunately, this incredibly biodiverse area has become one of the last remaining major tropical wilderness areas due to human activity. By transforming Amazonian habitats from forests to cow pastures, grasslands to croplands and swamps into cities (MacQuarrie 2001: 825), humans are threatening the Amazon to the verge of extinction. In the tropical rainforests, it is estimated that “a minimum of 3 to 4 animal or plant species are being lost each and every day, which means that at least 1,000 to 1,500 species of plants & animals are being 1 permanently removed from our planet each year” (MacQuarrie 2001: 326). This destructive rate means that many of these endangered species are speedily dying out before we even have the chance to find and study them, not to mention protect them. Nguyen, Quyen. Amazonian biodiversity: white-lipped peccaries. 2013. Tambopata Research Center, Peru. Nguyen, Quyen. Amazonian biodiversity: Red & Blue Macaws. 2013. Tambopata Research Center, Peru. 2 Nguyen, Quyen. Amazonian biodiversity: Jaguar. 2013. Tambopata River, Peru. Nguyen, Quyen. Amazonian biodiversity: Giant Otters. 2013. Tambopata River, Peru. 3 Peruvian Uakari The bald-headed uakari has a signature bright crimson bald face and “a short and bushy tail which is less than half to only one third of the head and body length of the animal” according to various studies done from 1981 to 2007 (Gron 2008). According to Hershkovitz (1987) and Barnett (2005), the presence of blood vessels near the surface of the skin results in a reddish appearance of the face and head in red-faced uakaris. (Gron 2008) The pelage of the Peruvian uakaris is reddish-orange but other uakaris’ color may vary widely from “reddish to orange and buffy to whitish or pale yellow” (Gron 2008). Taxonomy & Distribution The scientific name of the red or bald-headed uakaris in Peru is Cacajao calvus ucayalii, a reddish-orange New World monkey found only in Peru. The genus Cacajao has quite limited distribution in Amazonian western forests, and Cacajao calvus, the bald- headed uakari, is found in “regions of whitewater rivers, south of the Amazon, in Brazil and Peru” (Kinzey 1997: 208-209). Besides the C. c. ucayalii, there are three other Cacajao subspecies found in limited areas in Brazil and Colombia e.g. the C. c. calvus (white pelage) is confined between the Rios Japura and Solimoes in Brazil. C. calvus ucayalii, the subspecies we are examining, is only found in northeastern Peru, confined to the south by the Sheshea River, to the north and west by the Amazon River and Ucayali River respectively, and in the east by the Yavari River. (Gron 2008) 4 IUCN (International Union for Conservation of Nature) 2008. Range of the Cacajao calvus ucayalli in northeastern Peru. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1 <http://maps.iucnredlist.org/map.html?id=3416> Habitat & Ecology Generally uakaris are commonly found in or close to flooded or riparian forests. As opposed to Cacajao melanocephalus (whose face is black with plenty of dark, blackish hair) which is found in habitats associated with "black-water rivers,” Cacajao calvus is found in varzea forests, which is a type of Amazonian flooded forest “drained by white-water rivers where flooding occurs up to six months of the year, depositing new sediments and renewing the soil.” (Gron 2008) However there has been debate about whether bald uakaris’ habitat is fixed since they can be found in several types of habitat, including both flooded and unflooded várzea, swamp forest, white sand soil forests, floodplains and terra firme forest near várzea (Gron 2008). This switching in terms of habitat is a result of seasonal migration in the dry season when uakaris are said to move from previously flooded areas to terra firme. (Kinzey 1997: 210) They often stay within flooded areas to 5 enjoy periods of fruit abundance and move to “terra firme or other habitat types when more fruit is available outside of flooded forest” (Gron 2008). According to Leonard & Bennett (1996), Aquino (1988) and Boubli (2002), uakaris have been found in association with “other primates including spider monkeys (Ateles sp.), wooly monkeys (Lagothrix sp.), sakis (Chiropotes sp.& Pithecia sp.), capuchins (Cebus sp.), and squirrel monkeys (Saimiri sp.)” (Gron 2008). Such associations might provide predator protection (from harpy eagles, for example) and foraging benefits (Gron 2008). Food competition occurs among uakaris and other species with a dietary overlap such as “macaws (Ara sp.), squirrels and sympatric primates such as squirrel monkeys and capuchins” (Gron 2008). However the level of potential competition, according to Barnett (2005), Barnett et al. (2005) and Barnett (2008), requires additional quantitative assessment and is predicted to be quite low (Gron 2008). Diet C. calvus’ diet consists predominantly of seeds of unripe fruits (67%) followed by other parts of fruit (10%), flowers (6%), nectar, insects (5%) and unidentified foods (4%) (Gron 2008). “Aquino & Encarnación (1999) noted C. c. ucayaliieating 53 plant species from 20 families, of which 46% were consumed for their seeds. Of these, 67% had thick heavy husks and were consumed in the immature state” (Gron 2008). In the dry season, Peruvian red uakaris also move to unflooded forest to feed on palm fruit (Gron 2008). Conservation Status and Hypotheses: According to the IUCN Red List of Threatened Species (2008), the bald uakaris, Cacajao Calvus, are categorized as Vulnerable. Here is a history of the IUCN’s assessment of the C. calvus over the years (Veiga et al. 2008): 6 2003 – Near Threatened (IUCN 2003) 2003 – Near Threatened 2000 – Vulnerable 1996 – Vulnerable (Baillie and Groombridge 1996) 1996 – Vulnerable 1994 – Endangered (Groombridge 1994) 1990 – Vulnerable (IUCN 1990) 1988 – Vulnerable (IUCN Conservation Monitoring Centre 1988) 1986 – Vulnerable (IUCN Conservation Monitoring Centre 1986) 1982 – Vulnerable (Thornback and Jenkins 1982) Compared to the assessment in 1994 which put bald uakaris into the pool of endangered animals (only two steps away from completely extinction), the 2008 status of ‘vulnerable’ is somewhat more hopeful, indicating that conservation work had been done to rectify the dangerous drop in uakaris’ population in 1994. However, if we look at the 2003 assessment, uakaris’ have shifted closer to the extinction side of the spectrum by moving from Near Threatened in 2003 to Vulnerable in 2008. The IUCN’s justification for this change is that “there is reason to believe the species has declined by at least 30% over the past 30 years (three generations) due primarily to hunting and habitat loss” (Veiga et al. 2008). This paper explores those reasons that contribute to the uakari population decline for the past three decades with two main hypotheses: 1. Hunters preying on uakaris for bush meat are causing their population to decline. 2. Loggers who destroy uakaris’ arboreal habitat are depriving them of their home and food source. Hunting and logging are two main causes of Amazonia’s biodiversity and my hypotheses propose that they are the dominant actors causing uakaris’ population to decrease over the years. Biological factors such as the uakaris’ low reproductive rate (Barton 2006: 4) or their high rate of malaria infection (Gron 2008) might contribute to their slow recovery but 7 the external, human-induced effects are the more detrimental forces against uakaris’ population growth. After all, it is humans who have caused current extinction rates to skyrocket from 100 to 1000 times the normal extinction rate in the past, making the past two hundred years an “extinction spasm” (MacQuarrie 326) as catastrophic as the mass- extinction of all dinosaurs 65 million years ago. While the Mesozoic period came to a close due to an impact of a meteor collision, homo sapiens have managed to speed up our own destructive process entirely through man-made exploitative activities (MacQuarrie 326). Findings: HUNTING Uakaris are susceptible to hunting due to its primary range close to rivers (varzea forests). Aquino (1988) has suggested that uakari populations “close to the Ucayali and Amazon Rivers have been greatly reduced and in some areas exterminated, caused by hunting and habitat disturbance” (Veiga et al. 2008). Due to their riparian habitat, uakaris are prone to hunters, either preferentially hunted or taken when other primates are unavailable (Barnett and Brandon-Jones 1997). Hunted for Meat Sightings in 2003 of C. c. ucayalii on the Quebradas Tangarana and Tahuaillo in Peru show that the local C. c. ucayalii populations were frequently hunted. “On the Quebrada Blanco, we met a local hunter carrying a dead female that he had shot an hour’s walk from our camp,” Ward and Chism (2003) report.