Favoring recruitment as a conservation strategy to improve the resilience of long‐lived reptile populations: Insights from a population viability analysis

Rodrigues, Chloé Warret; Angin, Baptiste; Besnard, Aurélien

doi:10.1002/ece3.8021

Cited by 13 publications

(10 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, there are fewer adult breeders on the landscape producing fewer fledglings and these young birds have a low probability of becoming a territorial breeder creating a negative spiral of ever dwindling numbers of Spotted Owls. Even when adult survival in long-lived species remains high and stable, a population cannot persist if breeders that senesce or die are not replaced (Sergio et al 2021, Warret Rodriguez et al 2021). Therefore, the rearing conditions and resulting energetic tradeoffs that reduce survival and recruitment in pre-breeding individuals are important for population dynamics.…”

Section: Discussionmentioning

confidence: 99%

Juvenile Northern Spotted Owls with higher mass and intermediate levels of corticosterone have greater long-term survival

Mikkelsen

Lesmeister

O’Reilly

et al. 2023

Ornithological Applications

View full text Add to dashboard Cite

Early life experiences have carry-over effects that manifest in later life stages. Challenging rearing environments result in more energy invested in immediate survival and less energy on growth and maturation, which can decrease survival in both the short and long-term. One way to measure differences in energy allocation to growth between individuals is through physiological indices, such as concentrations of the metabolic hormone corticosterone, and body condition. Corticosterone increases in response to challenges to homeostasis and mobilizes stored fat and muscle to meet energetic demands. Maintaining elevated corticosterone can result in poor body condition and decreased survival. Juvenile or pre-breeding age classes are typically a substantial portion of the total population and serve key functions in population dynamics in many long-lived species. Thus, understanding how the rearing environment may influence demographics across life-history stages is crucial to understanding larger population dynamics. Yet, demographic models and conservation planning often lack vital rate estimates for early life stages because, prior to breeding, animals cannot be effectively sampled (i.e., they are unobservable). We used corticosterone concentrations in feathers and body mass of fledged juvenile Northern Spotted Owls (Strix occidentalis caurina) as indicators of potential energetic limitations early in life and used a multi-state modeling framework to quantify the effect of these indicators on apparent annual survival prior to claiming a territory (pre-territorial birds) and the probability of recruiting into the territorial population. Apparent annual survival for pre-territorial birds was higher for birds with greater mass, earlier banding dates, and intermediate levels of corticosterone. Birds with greater mass at banding were also more likely to recruit into the territorial population. Our results demonstrate the importance of early development and traditionally excluded life-history stages on long-term demographics. Although early life stages are difficult to observe, monitoring and conservation efforts may be improved by increasing studies on pre-territorial animals, control of Barred Owls, and conservation of forest structures important for Spotted Owls. This may contribute to increased juvenile survival and recruitment.

show abstract

Section: Discussionmentioning

confidence: 99%

Juvenile Northern Spotted Owls with higher mass and intermediate levels of corticosterone have greater long-term survival

Mikkelsen

Lesmeister

O’Reilly

et al. 2023

Ornithological Applications

View full text Add to dashboard Cite

show abstract

“…Indeed, juveniles are more vulnerable than adults as their foraging skills (including their ability to dive, to capture prey and to find productive feeding grounds) are not yet fully developed, and their experience to escape predators is minimal [43]. Moreover, juvenile survival can have a critical impact on the population dynamics, especially in long-lived species [44] as it is increasingly evidenced on various taxa (see [35,[45][46][47]). Emperor penguins start breeding earliest at age 4-5 years, lay only one egg per pair and year, and only have an annual chance of 55% to bring a chick to fledging [32].…”

Section: Discussionmentioning

confidence: 99%

“…However, reproduction can also significantly drive population dynamics and species with high adult survival can still have a declining population owing to an insufficient recruitment rate (i.e. juvenile survival to adulthood), see [35,[45][46][47]. Therefore, for successful conservation, we need to consider the habitat range of all age classes.…”

Section: Discussionmentioning

confidence: 99%

“…Long-lived seabirds, emperor penguins reach sexual maturity between 4 and 8 years [ 33 , 34 ]. However, little is known about the first years at sea of the species, even though the survival of this age class referred as ‘juvenile’ is crucial for the viability of the global population [ 33 , 35 ]. To date, a total of only 48 juvenile emperor penguins have been tracked.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Juvenile emperor penguin range calls for extended conservation measures in the Southern Ocean

et al. 2022

View full text Add to dashboard Cite

To protect the unique and rich biodiversity of the Southern Ocean, conservation measures such as marine protected areas (MPAs) have been implemented. Currently, the establishment of several additional protection zones is being considered based on the known habitat distributions of key species of the ecosystems including emperor penguins and other marine top predators. However, the distribution of such species at sea is often insufficiently sampled. Specifically, current distribution models focus on the habitat range of adult animals and neglect that immatures and juveniles can inhabit different areas. By tracking eight juvenile emperor penguins in the Weddell Sea over 1 year and performing a meta-analysis including previously known data from other colonies, we show that conservation efforts in the Southern Ocean are insufficient for protecting this highly mobile species, and particularly its juveniles. We find that juveniles spend approximately 90% of their time outside the boundaries of proposed and existing MPAs, and that their distribution extends beyond (greater than 1500 km) the species' extent of occurrence as defined by the International Union for Conservation of Nature. Our data exemplify that strategic conservation plans for the emperor penguin and other long-lived ecologically important species should consider the dynamic habitat range of all age classes.

show abstract

“…Nest sites.-Successful nesting and recruitment are essential for population size maintenance and long-term survival (Bock et al 2016;Warret Rodrigues et al 2021). Although this study was not specifically aimed at identifying communal nest sites, we did survey for and record sites with hatchling emerging holes, four of which were encountered.…”

Section: )mentioning

confidence: 99%

Population estimate, natural history and conservation of the melanisticIguana Iguanapopulation on Saba, Caribbean Netherlands

Burg

Madden²,

Debrot

2022

Preprint

View full text Add to dashboard Cite

Intraspecific diversity is among the most important biological variables, although still poorly understood for most species. Iguana iguana is a Neotropical lizard known from Central and South America, including from numerous Caribbean islands. Despite the presence of native melanistic I. iguana populations in the Lesser Antilles, these have received surprisingly little research attention. Here we assessed population size, distribution, degree of melanism, and additional morphological and natural history characteristics for the melanistic iguanas of Saba, Caribbean Netherlands based on a one-month fieldwork visit. Using Distance sampling from a 38-transect dataset we estimate the population size at 8233 ±2205 iguanas. Iguanas mainly occurred on the southern and eastern sides of the island, between 180-390 m (max altitude 530 m), with highest densities both in residential and certain natural areas. Historically, iguanas were relatively more common at higher altitudes, probably due to more extensive forest clearing for agricultural reasons. No relationship was found between the degree of melanism and elevation, and few animals were completely melanistic. Furthermore, we found that body-ratio data collection through photographs is biased and requires physical measuring instead. Although the population size appears larger than previously surmised, the limited nesting sites and extremely low presence of juvenile and hatchling iguanas (2.4%), is similarly worrying as the situation for I. delicatissima on neighboring St. Eustatius. The island's feral cat and large goat population are suspected to impact nest site quality, nest success, and hatchling survival. These aspects require urgent future research to guide necessary conservation management.

show abstract

Favoring recruitment as a conservation strategy to improve the resilience of long‐lived reptile populations: Insights from a population viability analysis

Abstract: This is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 13 publications

References 67 publications

Juvenile Northern Spotted Owls with higher mass and intermediate levels of corticosterone have greater long-term survival

Juvenile Northern Spotted Owls with higher mass and intermediate levels of corticosterone have greater long-term survival

Juvenile emperor penguin range calls for extended conservation measures in the Southern Ocean

Population estimate, natural history and conservation of the melanisticIguana Iguanapopulation on Saba, Caribbean Netherlands

Contact Info

Product

Resources

About