Long-term, climate-driven phenological shift in a tropical large carnivore

Abstract

Understanding the degree to which animals are shifting their phenology to track optimal conditions as the climate changes is essential to predicting ecological responses to global change. Species at low latitudes or high trophic levels are theoretically expected to exhibit weaker phenological responses than other species, but limited research on tropical systems or on top predators impedes insight into the contexts in which these predictions are upheld. Moreover, a lack of phenological studies on top predators limits understanding of how climate change impacts propagate through entire ecosystems. Using a 30-y dataset on endangered African wild dogs ( Lycaon pictus ), we examined changes in reproductive phenology and temperatures during birthing and denning over time, as well as potential fitness consequences of these changes. We hypothesized that their phenology would shift to track a stable thermal range over time. Data from 60 packs and 141 unique pack-years revealed that wild dogs have delayed parturition by 7 days per decade on average in response to long-term warming. This shift has led to temperatures on birthing dates remaining relatively stable but, contrary to expectation, has led to increased temperatures during denning periods. Increased denning temperatures were associated with reduced reproductive success, suggesting that a continued phenological shift in the species may become maladaptive. Such results indicate that climate-driven shifts could be more widespread in upper trophic levels than previously appreciated, and they extend theoretical understanding of the species traits and environmental contexts in which large phenological shifts can be expected to occur as the climate changes.

Physiological tipping points in the relationship between foraging success and lifetime fitness of a long‐lived mammal

“…Tracking individuals over time to determine whether predation or starvation drives mortality can provide valuable insight into selective pressures shaping behavioural strategies over evolutionary time, as most (87%) of the variation in lifetime reproductive success was due to differences in lifespan. Our integrated framework (Figure 4) for investigating links between reproductive output, lifespan and behavioural strategies could be adapted to other taxa through long‐term monitoring programs (Schradin & Hayes, 2017), which are disproportionately valuable given their cost (Abrahms et al, 2022; Hughes et al, 2017).…”

Assessing the breeding phenology of a threatened frog species using eDNA and automatic acoustic monitoring

“…Among the widely documented consequences of global warming are phenological shifts–changes in timing of seasonal activities such as migration ( Van Buskirk, Mulvihill & Leberman, 2009 ), flowering ( CaraDonna, Iler & Inouye, 2014 ), chorusing in frogs ( Klaus & Lougheed, 2013 ), and spawning in fish ( Lynch et al, 2016 ). Consequences of phenological shifts can be at the population level, such as phenological isolation from other populations and concomitantly loss of genetic connectivity ( Heard, Riskin & Flight, 2012 ), but also at the individual scale ( Stillman, 2019 ; Abrahms et al, 2022 ). For example, such shifts can influence reproductive success by creating a temporal mismatch between offspring and access to their preferred prey ( Visser, te Marvelde & Lof, 2012 ; Reed, Jenouvrier & Visser, 2013 ), reducing successful development and fitness of individuals.…”

Climate change is predicted to cause population collapse in a cooperative breeder

“…Using such data, researchers have been able to estimate rates of recruitment (Abrahms et al, 2022; Woodroffe et al, 2017), survival (Rabaiotti et al, 2021; Woodroffe, 2011a; Woodroffe et al, 2007) and dispersal (Behr et al, 2020; Woodroffe, O'Neill, & Rabaiotti, 2020; Woodroffe, Rabaiotti, et al, 2020). Studies have shown that African wild dog vital rates are impacted by high ambient temperatures across a number of populations, with lower adult survival (Rabaiotti et al, 2021) and recruitment (Abrahms et al, 2022; Woodroffe et al, 2017) at higher temperatures. The time between one litter and the next (the inter‐birth interval) is also longer at higher ambient temperatures at a site with aseasonal breeding (Woodroffe et al, 2017).…”