Factors influencing heterogeneity in female reproductive success in a Critically Endangered population of bottlenose dolphins

Knowledge of factors affecting the survival of individuals and their reproductive success is essential for threatened species management, but studies assessing these factors are lacking for many threatened rock-wallaby species. In this study we investigated the factors influencing the breeding performance of females and the survival of pouch young in a wild colony of the threatened brush-tailed rock-wallaby. Individuals were trapped between October 2000 and April 2004. More than 50% of the females in the colony were breeding below their full potential and giving birth to only one offspring per year. Most females within the colony bred in synchrony, with a substantial birth peak evident during autumn. Pouch young born in autumn left the pouch during spring and were weaned during summer and autumn when forage was most abundant. Pouch young born during the autumn birth peak or in winter had a substantially higher probability of surviving through to pouch emergence than those born during spring or summer. This study provides demographic parameters that may be used in population models and for comparison with other populations, particularly those that are small and declining. To optimise reproductive success in reintroduction programs, females in good condition and with small pouch young should be released at the end of the wettest season.

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Food-provisioning negatively affects calf survival and female reproductive success in bottlenose dolphins

Scientific Reports ◽

10.1038/s41598-019-45395-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

V. Senigaglia ◽

F. Christiansen ◽

K. R. Sprogis ◽

J. Symons ◽

L. Bejder

Keyword(s):

Reproductive Success ◽

Bayes Factor ◽

Linear Models ◽

Southern Oscillation ◽

Bottlenose Dolphins ◽

Food Provisioning ◽

Female Reproductive Success ◽

Climatic Fluctuations ◽

Calf Survival

AbstractFood-provisioning of wildlife can facilitate reliable up-close encounters desirable by tourists and, consequently, tour operators. Food-provisioning can alter the natural behavior of an animal, encouraging adverse behavior (e.g. begging for food handouts), and affect the reproductive success and the viability of a population. Studies linking food-provisioning to reproductive success are limited due to the lack of long-term datasets available, especially for long-lived species such as marine mammals. In Bunbury, Western Australia, a state-licensed food-provisioning program offers fish handouts to a limited number of free-ranging bottlenose dolphins (Tursiops aduncus). Coupled with long-term historical data, this small (<200 individuals), resident dolphin population has been extensively studied for over ten years, offering an opportunity to examine the effect of food-provisioning on the reproductive success of females (ntotal = 63;nprovisioned females = 8). Female reproductive success was estimated as the number of weaned calves produced per reproductive years and calf survival at year one and three years old was investigated. The mean reproductive success of provisioned and non-provisioned females was compared using Bayes factor. We also used generalized linear models (GLMs) to examine female reproductive success in relation to the occurrence of food-provisioning, begging behavior and location (within the study area). Furthermore, we examined the influence of these variables and birth order and climatic fluctuations (e.g. El Niño Southern Oscillation) on calf survival. Bayes factor analyses (Bayes factor = 6.12) and results from the best fitting GLMs showed that female reproductive success and calf survival were negatively influenced by food-provisioning. The negative effects of food-provisioning, although only affecting a small proportion of the adult females’ population (13.2%), are of concern, especially given previous work showing that this population is declining.

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Significance of wounding to female reproductive success in Hawaiian monk seals (Monachus schauinslandi) at Laysan Island

Canadian Journal of Zoology ◽

10.1139/z93-067 ◽

1993 ◽

Vol 71 (3) ◽

pp. 469-474 ◽

Cited By ~ 28

Author(s):

Lisa M. Hiruki ◽

Ian Stirling ◽

William G. Gilmartin ◽

Thea C. Johanos ◽

Brenda L. Becker

Keyword(s):

Reproductive Success ◽

Adult Male ◽

Reproductive Rate ◽

Lactation Period ◽

Female Reproductive Success ◽

Monachus Schauinslandi ◽

Lower Survival Rate ◽

Adult Females ◽

Pup Survival ◽

Monk Seals

We studied reproductive rate, length of lactation period, pup survival, and mortality of injured and uninjured female Hawaiian monk seals (Monachus schauinslandi) on Laysan Island, northwestern Hawaiian Islands, in 1983 – 1989. The severity and timing of nonfatal injuries were influential in determining their effect on female reproductive success. There was a tendency towards a shorter mean lactation period and lower survival rate of pups for females with major injuries than for uninjured females. Females with minor injuries were similar to uninjured females in terms of reproductive rate, length of lactation, and pup survival. For females injured shortly before the birth of their pup or during lactation, pup survival was lower than for uninjured females, whereas for females injured during the year prior to pupping, measures of reproductive success were not significantly different from those for uninjured females. Immature (aged 4 – 8 years) females entering the reproductive population were injured by adult male seals significantly more often than females aged 0 – 3 years, but at a similar rate to adult females. The major effect of injuries on female reproductive success is an increase in female mortality: 87.5 % of the adult females (n = 16) that died on Laysan Island in 1983 – 1989 sustained injuries from adult male seals.

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Female reproductive success in a species with an age-inversed hierarchy

Integrative Zoology ◽

10.1111/1749-4877.12201 ◽

2016 ◽

Vol 11 (6) ◽

pp. 433-446 ◽

Cited By ~ 1

Author(s):

Dorien DE VRIES ◽

Andreas KOENIG ◽

Carola BORRIES

Keyword(s):

Reproductive Success ◽

Female Reproductive Success

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Settlement patterns, foraging behavior, and reproductive success of ospreys along a heterogeneous riverine corridor

Canadian Journal of Zoology ◽

10.1139/z06-190 ◽

2007 ◽

Vol 85 (1) ◽

pp. 56-62 ◽

Cited By ~ 5

Author(s):

Peter J. Harmata ◽

Marco Restani ◽

Alan R. Harmata

Keyword(s):

Reproductive Success ◽

Foraging Behavior ◽

Settlement Patterns ◽

Missouri River ◽

Nest Density ◽

River Section ◽

Pandion Haliaetus ◽

Factors Influencing ◽

Spatial Use ◽

Gill Netting

In 1998 and 1999, we determined the spatial distribution, foraging behavior, and reproductive success of ospreys ( Pandion haliaetus (L., 1758)) nesting along the upper Missouri River, Montana. We combined our data with that collected in the same area in 1981–1982 and 1990–1991 to investigate factors influencing settlement patterns. The study area was composed of four distinct habitats, three reservoirs and one free-flowing river section. Although number of occupied nests on each habitat increased from 1981–1982 to 1998–1999, the greatest percentage increases in nest density occurred on habitats previously hypothesized to contain the least prey. Osprey reproductive success was positively related to foraging rates, which differed across habitats, being highest on reservoirs and lowest on the free-flowing river. However, reproductive success was adequate for replacement on each habitat. Most fish consumed by ospreys on each habitat were suckers (Catostomidae), followed by salmonids and cyprinids. Fish density, determined from gill netting, was highest on the largest and shallowest reservoir. Over two decades, ospreys shifted their relative spatial use of the upper Missouri River such that reservoirs were occupied first and the free-flowing river section was occupied last. The degree to which presence of conspecifics, distribution of nest trees and prey, and dispersal affected settlement patterns probably varied by spatial scale.

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Breeding biology of the Critically Endangered Tahiti MonarchPomarea nigra, a bird with a low productivity

Bird Conservation International ◽

10.1017/s095927091700048x ◽

2017 ◽

Vol 28 (4) ◽

pp. 606-619 ◽

Cited By ~ 1

Author(s):

CAROLINE BLANVILLAIN ◽

THOMAS GHESTEMME ◽

TEHANI WITHERS ◽

MARK O’BRIEN

Keyword(s):

Reproductive Success ◽

French Polynesia ◽

Egg Laying ◽

Breeding Biology ◽

Critically Endangered ◽

Tropical Island ◽

Island Endemics ◽

Nest Activity ◽

Considerable Length ◽

One Year

SummaryWe studied the breeding biology of Tahiti MonarchPomarea nigra, a ‘Critically Endangered’ forest bird endemic to Tahiti (French Polynesia). Nest activity was monitored from 1998 to 2002, and again from 2008 to 2015. During these 12 years, only 2–13 breeding pairs per year produced hatchlings. Egg-laying occurred all year, but usually increased between August and January, peaking around November. Of the 200 nests monitored, 33 (16%) were abandoned shortly after construction, 71 had an egg laid immediately after the nest were completed (34 %) and 96 nests (46 %) had a pre-incubation phase of 18.9 ± 1.9 days (3–62 days;n= 47 nests), during which the birds visited the nest on an irregular basis. Half (49 of 96) of these nests were abandoned before an egg was laid, with incubation subsequently commencing at the remaining nests (n= 47). Although both sexes incubated for an average of 13.6 ± 0.3 days (range 13–15), the female usually spent more time incubating than the male. Only one young per nest was ever observed. The average nestling phase was 15.5 ± 0.7 days (range 13 to 20 days). Parents continue to feed the young after fledging for 74 ± 4.7 days (range 42–174). As with many tropical island endemics, the Tahiti Monarch has low reproductive productivity as indicated by the fact that: 1) only 56% of pairs attempt to lay an egg in any one year, 2) most pairs attempt only one brood per year and 3) the considerable length of the nesting and fledging phases. Because of its low productivity, maximising the reproductive success of the Tahiti Monarch is essential to secure its recovery.

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Riverine characteristics and adult demography influence female lake sturgeon (Acipenser fulvescens) spawning behavior, reproductive success, and ovarian quality

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2018-0141 ◽

2019 ◽

Vol 76 (7) ◽

pp. 1147-1160 ◽

Cited By ~ 4

Author(s):

Kari J. Dammerman ◽

Molly A.H. Webb ◽

Kim T. Scribner

Keyword(s):

Reproductive Success ◽

Behavioral Plasticity ◽

Lake Sturgeon ◽

Operational Sex Ratio ◽

Plasma Testosterone ◽

Acipenser Fulvescens ◽

Reproductive Costs ◽

Arrival Date ◽

Factors Influencing ◽

Yearly Means

Abiotic conditions and demographic factors can influence the timing of spawning. Behavioral plasticity allows females to select spawning conditions that are conducive to offspring development; however, reproductive costs associated with delaying spawning are not well understood. In this study, factors influencing timing of female spawning, residence time (RT), and reproductive success (RS) during two seasons were determined, and plasma testosterone concentrations were used to quantify atretic rates in a wild, lake sturgeon (Acipenser fulvescens) population. For the 123 females monitored, RT ranged from 1 to 23 days and was influenced by arrival date, temperature, discharge, and male number, with the latter having the largest influence. RS varied due to arrival date, temperature, discharge, male number, male length, and operational sex ratio. Two females had testosterone levels indicative of atresia and RS estimates lower than yearly means; however, most females had normal ovaries, suggesting little reproductive costs of plasticity in spawning ground residency time. Results demonstrate the multitude of factors influencing female reproductive behavior and RS, highlighting the importance of abiotic and demographic conditions to recruitment in wild populations.

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