Breeding seasonality in the lowland paca (Cuniculus paca) in Amazonia: interactions with rainfall, fruiting, and sustainable hunting

Abstract

The resilience of a given species to hunting is conditioned by the effect of potential threats upon the more sensitive periods in its life history, such as when animals are breeding. We investigated the environmental drivers of breeding seasonality in the lowland paca (Cuniculus paca), and the potential impact of hunting on the species. As part of a participative study with hunters in 2 Amazonian sites, we obtained reproductive organs of pacas as well as information on the hunters’ daily wild meat extraction. Using data on rainfall, river water level, and fruiting phenology from the 2 study sites, we applied generalized additive models for location, scale, and shape (GAMLSS) to examine the effect of climatic and environmental factors on paca reproduction. Forest fruiting was directly linked to higher pregnancy rates in pacas, and when lactation and weaning of offspring mostly occurred. Hunting was highly seasonal in all studied years and positively correlated with higher levels of river water. The coincidence between hunting patterns and paca reproductive cycles during the wet season resulted in more pregnant females being harvested. In addition to the known slow reproductive rate of pacas, the disproportionate offtake of pregnant females may affect the long-term sustainability of hunting of this species. Reducing hunting during the flooded season may not be feasible because the lowland paca provides most of the wild meat consumed by thousands of rural Amazonians during this period. However, options to offset the negative effects of killing of pregnant females could include the zoning of hunting areas or encouraging hunters to target primarily males. Our results indicate that strategies for the sustainable harvest of pacas and other heavily hunted Amazonian mammals should consider the interaction between the species’ reproductive cycles and hunting by local people in order to enhance conservation and management efforts. A resiliência de uma espécie à caça é condicionada pela sua capacidade reprodutiva intrínseca e pelo efeito de potenciais ameaças durante os períodos mais sensíveis de sua história de vida, como o período reprodutivo. Neste trabalho, nós investigamos os fatores ambientais que determinam a sazonalidade reprodutiva da paca (Cuniculus paca) e o potencial impacto da caça sobre a espécie. Em um estudo participativo de 15 anos em duas áreas da Amazônia, obtivemos órgãos reprodutivos de pacas doados voluntariamente por caçadores, bem como informações sobre seus padrões diários de caça. Usando informações sobre precipitação, nível d’água dos rios e fenologia de frutificação, nós aplicamos modelos aditivos generalizados (GAMLSS) para examinar o efeito de fatores climáticos e ambientais na reprodução da paca. A precipitação esteve positivamente ligada a uma maior frutificação, que por sua vez foi correlacionada com maiores taxas de prenhes da paca e com os períodos de lactação e desmame da prole. A caça de paca foi altamente cíclica ao longo dos anos e positivamente associada aos níveis d’água mais elevados. A convergência entre os padrões de caça e os ciclos reprodutivos de paca resulta na extração de um grande número de fêmeas grávidas. Juntamente com a lenta taxa de reprodução da espécie, a captura desproporcional de fêmeas grávidas pode afetar a sustentabilidade do uso da paca. Reduzir a caça durante os períodos de inundação pode não ser viável, pois a paca é a espécie responsável por fornecer grande parte da carne silvestre consumida por milhares de moradores rurais da Amazônia neste período. No entanto, ações para compensar os efeitos negativos da extração de pacas grávidas poderiam incluir o zoneamento de áreas de caça ou o incentivo aos caçadores em abater preferencialmente machos. Nossos resultados indicam que estratégias para a extração sustentável da paca e outras espécies cinegéticas amazônicas devem considerar a interação entre a reprodução e a caça pela população local, a fim de melhorar as ações de conservação e manejo no bioma.

Temporal patterns of visitation of birds and mammals at mineral licks in the Peruvian Amazon

“…Model results for the red brocket deer, collared peccary, and agouti also showed seasonal visitation, even though these species are known to breed year‐round (El Bizri et al., 2018; Mayor et al., 2011). Several other studies have described increased visitation at mineral licks before reproduction for other species, including Amazonian bats (Bravo et al., 2008; Voigt et al., 2008), white‐tailed deer (Atwood & Weeks, 2002, 2003), and African elephants (Holdø et al., 2002).…”

Urban wild meat consumption and trade in central Amazonia

“…Both species are declining in central Amazonia (Parry & Peres 2015). Other highly cited species, such as lowland paca, are also affected by hunting in Amazonia (e.g., Valsecchi et al 2014;El Bizri et al 2018), but are listed as least concern by IUCN.…”

Age at sexual maturity, first parturition and reproductive senescence in wild lowland pacas (Cuniculus paca): Implications for harvest sustainability

“…Hence, even when there is consideration of the findings in the present study that pacas sexually mature earlier than what was previously reported, pacas still reproduce less efficiently than expected when calculations were based on data from previous studies. In addition, pacas produce one offspring per gestation and in Amazonia there is an unexpected seasonal pattern of reproduction that converges with periods when there is greater hunting intensity and consequently the harvesting of a large number of pregnant females for human consumption (Oliveira et al, 2007;Mayor et al, 2013Mayor et al, , 2017Valsecchi et al, 2014;El Bizri et al, 2018). When results of the present and previous studies are considered, there needs to be a critical review of previous population sustainability assessments for the species, and calculations of sustainable yields for future in situ management actions (ie., establishment of hunting quotas) should be more conservative.…”

“…Additionally, the paca is a uniparous species with rare cases of twin gestations (Pérez and Hernández, 1979;Merrit, 1989;Oliveira et al, 2003Oliveira et al, , 2007. In the Amazon, the lowland paca in its natural habitat has 1.37-1.48 annual parturitions that are seasonally distributed depending on the amounts of fruitification and river water, with a long estimated farrowing interval of 247-266 days (Mayor et al, 2013;El Bizri et al, 2018).…”