Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals

1999 ◽  
Keyword(s):  
Population Structure ◽  
Null Hypothesis ◽  
Small Population ◽  
Qualitative Result ◽  
Killer Whales ◽  
Demographic Stochasticity ◽  
Marine Animals ◽  
Unusual Event ◽  
Environmental Causes ◽  
External Causes

<em>Abstract.</em> —A suite of stage- and age-classified models are constructed to determine whether an apparently unusual event is the result of external, environmental causes in a small population. These models are used as a baseline, or null hypothesis, that such an event may result from population structure and demographic stochasticity. An observed multiyear reproductive delay in a pod of killer whales <em>Orcinus orca </em> is used as an example of this process. All models, regardless of their complexity, give the same qualitative result: the observed reproductive delay could not be explained by pod composition and demographic stochasticity; external causes have to be sought to explain this phenomenon.

Using opportunistic photo-identifications to detect a population decline of killer whales (Orcinus orca) in British and Irish waters

2013 ◽  
Vol 94 (6) ◽  
pp. 1327-1333 ◽  
Author(s):  
Suzanne Beck ◽  
Andrew D. Foote ◽  
Sandra Kötter ◽  
Olivia Harries ◽  
Laura Mandleberg ◽  
...  
Keyword(s):  
Killer Whale ◽  
Population Decline ◽  
Small Population ◽  
High Ratio ◽  
Older Individuals ◽  
Adult Males ◽  
Killer Whales ◽  
Demographic Stochasticity ◽  
Photo Identification ◽  
Bayesian Formulation

An assemblage of killer whales that has been sighted in waters off the west coast of the British Isles and Ireland has previously been shown to be isolated from other North Atlantic killer whale communities based on association patterns. By applying a Bayesian formulation of the Jolly–Seber mark-recapture model to the photo-identification data compiled from opportunistic photographic encounters with this population of killer whales, we show that such sparse and opportunistically-collected data can still be valuable in estimating population dynamics of small, wide-ranging groups. Good quality photo-identification data was collected from 32 encounters over 19 years. Despite a cumulative total of 77 identifications from these encounters, just ten individuals were identified and the remaining 67 identifications were re-sights of these ten animals. There was no detected recruitment through births during the study and, as a result, the population appears to be in a slight decline. The demography of the population was highly skewed towards older individuals and had an unusually high ratio of adult males, and we suggest that demographic stochasticity due to a small population size may be further impacting the population growth rate. We recommend that this population be managed as a separate conservation unit from neighbouring killer whale populations.

scholarly journals The abundance of false killer whale, Pseudorca crassidens (Artiodactyla: Delphinidae) in coastal waters of Golfo Dulce and Osa Peninsula, Costa Rica

2020 ◽  
Vol 68 (2) ◽  
Author(s):  
Erika Sánchez Robledo ◽  
Lenin Enrique Oviedo Correa ◽  
David Herra-Miranda ◽  
Juan Diego Pacheco-Polanco ◽  
Sierra Goodman ◽  
...  
Keyword(s):  
Costa Rica ◽  
Population Size ◽  
Killer Whale ◽  
Small Population ◽  
Killer Whales ◽  
Apparent Survival ◽  
Osa Peninsula ◽  
Small Population Size ◽  
False Killer Whale ◽  
Pseudorca Crassidens

Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social species that live in groups with individuals of mixed ages and sex classes. False killer whales have been documented since the late 1990s in Southwestern Costa Rica. Objective: To estimate the abundance of false killer whales in Osa Peninsula waters. Methods: Cetacean surveys off the Osa Peninsula Waters (OPW), Costa Rica, yielded opportunistic encounters with false killer whales in Drake Bay and Caño Island (2001-2015) and observations during formal surveys in Golfo Dulce (2005-2015). Photo-identification data was analyzed using capture-mark-recapture models in the study area, through an open population (POPAN) framework, considering the effect of time on the parameters apparent survival and capture probability, producing an abundance estimate for a superpopulation in the entire study area. Results: False killer whale abundance in OPW is characterized by a small population size of no more than 100 individuals, complemented by a very low probability of encounter and a contrasting high apparent survival. Conclusions: This population estimate should be taken as conservative, however, the small population size of less than 100 individuals should be considered vulnerable, in contrast to the increasing anthropogenic impacts in the coastal seascape. We argue the potential occurrence of population units along the coastal seascape of the Pacific littoral and oceanic island-associated units at Isla del Coco.

scholarly journals Quantitative study of activated sludge population structure

2021 ◽  
Vol 2130 (1) ◽  
pp. 012026
Author(s):  
R Babko ◽  
V Pliashechnyk ◽  
T Kuzmina ◽  
J Zaburko ◽  
Y Danko ◽  
...  
Keyword(s):  
Population Structure ◽  
Activated Sludge ◽  
Quantitative Study ◽  
High Reliability ◽  
Small Population ◽  
Glass Slide ◽  
Population Densities ◽  
Treatment Control ◽  
Free Swimming ◽  
Short Time

Abstract A quantitative study of the population structure of activated sludge is an important component of biological wastewater treatment control. However, in the studying of live samples of the activated sludge, some complications arise, in particular, associated with the relatively short time of the subsample suitability. A subsample is the part of the sample that is placed on a glass slide and in which organisms are counted. The issue of optimization of counts of organisms with large amplitude of population density is considered. The results of counting ciliated protozoa in activated sludge were described. The samples were counted in 45 sub-samples of 25 µl each. An average of 10 counts was required to achieve high reliability in determining population densities with more than or equal to 1 specimen per 25 µl in sub-samples. For small population densities (less one specimen per 25 µl) of free-swimming, crawling, and sessile ciliates, 30 counts are necessary. When the density of colonial protozoan populations is established, the number of counts should be increased to 40, especially when colonies with significant differences in the number of zooids are found.

scholarly journals Species-area relationships emerge from multiple coexistence mechanisms

2021 ◽  
Author(s):  
David Garcia-Callejas ◽  
Ignasi Bartomeus ◽  
Oscar Godoy
Keyword(s):  
Species Richness ◽  
Spatial Heterogeneity ◽  
Species Interactions ◽  
Spatial Scales ◽  
Single Species ◽  
Small Population ◽  
Collective Effects ◽  
Demographic Stochasticity ◽  
Species Dominance ◽  
Species Area

The increase of species richness with area is a universal phenomenon on Earth. However, this observation contrasts with our poor understanding of how these species-area relationships (SARs) emerge from the collective effects of area, spatial heterogeneity, and local interactions. By combining a structuralist approach with five years of empirical observations in a highly-diverse grassland, we show that,contrary to expectations, spatial heterogeneity plays a little role in the accumulation of species richness with area in our system. Instead, as we increase the sampled area more species combinations are realized, and they coexist mainly due to direct pairwise interactions rather than by changes in single-species dominance or by indirect interactions. We also identify a small set of transient species with small population sizes that are consistently found across spatial scales. These findings empirically support the importance of the architecture of species interactions together with demographic stochasticity for driving SARs.

scholarly journals Is pertussis actually reemerging? Insights from an individual-based model

2001 ◽  
Vol 17 (3) ◽  
pp. 491-500 ◽  
Author(s):  
Cláudia Torres Codeço ◽  
Paula Mendes Luz
Keyword(s):  
Population Structure ◽  
Whooping Cough ◽  
Acute Infection ◽  
Small Population ◽  
Individual Risk ◽  
Natural Immunity ◽  
Individual Based Model ◽  
Adults And Children ◽  
Wide Scale ◽  
Age Structured

In this paper, we introduce a spatially explicit, individual-based model developed to simulate the dynamics of pertussis in a small population. With this simulation approach, complex epidemic systems can be built using information on parasite population structure (strain diversity, virulence diversity, etc.), human population structure (individual risk, age structure, interaction matrices, immune response, etc.), as well as mechanisms of evolution and learning. We parameterized our model to describe pertussis in an age-structured community. Pertussis or whooping cough is an acute infection of the respiratory tract caused by Bordetella pertussis. Despite wide-scale vaccination in many countries, this disease is reemerging throughout the world in both adults and children. Emergence has been explained by many factors: wane of vaccine and natural immunity, increase of asymptomatic carriers, and/or natural selection of non-vaccine strains. Here, we model these hypotheses and analyze their potential impact on the observed increase of pertussis notification.

scholarly journals Nuclear and Mitochondrial Patterns of Population Structure in North Pacific False Killer Whales (Pseudorca crassidens)

2014 ◽  
Vol 105 (5) ◽  
pp. 611-626 ◽  
Author(s):  
K. K. Martien ◽  
S. J. Chivers ◽  
R. W. Baird ◽  
F. I. Archer ◽  
A. M. Gorgone ◽  
...  
Keyword(s):  
Population Structure ◽  
North Pacific ◽  
Killer Whales ◽  
Pseudorca Crassidens

scholarly journals DNA fingerprinting and analysis of population structure in the chestnut blight fungus, Cryphonectria parasitica.

Genetics ◽  
1992 ◽  
Vol 131 (2) ◽  
pp. 297-306 ◽  
Author(s):  
M G Milgroom ◽  
S E Lipari ◽  
W A Powell
Keyword(s):  
Population Structure ◽  
Null Hypothesis ◽  
Random Mating ◽  
Population Sample ◽  
Cryphonectria Parasitica ◽  
The Other ◽  
Chestnut Blight ◽  
Dna Fingerprints ◽  
Restriction Fragments ◽  
Chestnut Blight Fungus

Abstract We analyzed DNA fingerprints in the chestnut blight fungus, Cryphonectria parasitica, for stability, inheritance, linkage and variability in a natural population. DNA fingerprints resulting from hybridization with a dispersed moderately repetitive DNA sequence of C. parasitica in plasmid pMS5.1 hybridized to 6-17 restriction fragments per individual isolate. In a laboratory cross and from progeny from a single perithecium collected from a field population, the presence/absence of 11 fragments in the laboratory cross and 12 fragments in the field progeny set segregated in 1:1 ratios. Two fragments in each progeny set cosegregated; no other linkage was detected among the segregating fragments. Mutations, identified by missing bands, were detected for only one fragment in which 4 of 43 progeny lacked a band present in both parents; no novel fragments were detected in any progeny. All other fragments appeared to be stably inherited. Hybridization patterns did not change during vegetative growth or sporulation. However, fingerprint patterns of single conidial isolates of strains EP155 and EP67 were found to be heterogenous due to mutations that occurred during culturing in the laboratory since these strains were first isolated in 1976-1977. In a population sample of 39 C. parasitica isolates, we found 33 different fingerprint patterns with pMS5.1. Most isolates differed from all other isolates by the presence or absence of several fragments. Six fingerprint patterns each occurred twice. Isolates with identical fingerprints occurred in cankers on the same chestnut stems three times; isolates within the other three pairs were isolated from cankers more than 5 m apart. The null hypothesis of random mating in this population could not be rejected if the six putative clones were removed from the analysis. Thus, a rough estimate of the clonal fraction of this population is 6 in 39 isolates (15.4%).

scholarly journals Estimating the density of small population of leopard Panthera pardus using multi-session photographic□sampling data

2020 ◽  
Author(s):  
Mohammad S. Farhadinia ◽  
Pouyan Behnoud ◽  
Kaveh Hobeali ◽  
Seyed Jalal Mousavi ◽  
Fatemeh Hosseini-Zavarei ◽  
...  
Keyword(s):  
Population Density ◽  
Arid Regions ◽  
Animal Movement ◽  
Small Population ◽  
Conservation Priorities ◽  
Large Carnivores ◽  
Panthera Pardus ◽  
Demographic Stochasticity ◽  
Density Estimates ◽  
Capture Recapture

AbstractWest Asian drylands host a number of threatened large carnivores, including the leopard (Panthera pardus) which is limited to spatially scattered landscapes with generally low primary productivity. While conservation efforts have focused on these areas for several decades, reliable population density estimates are missing. Spatially-explicit capture-recapture (SECR) methodology, incorporating animal movement in density estimates, is widely used to monitor populations of large carnivores. We employed multi-session SECR modeling to estimate the density of a small population of leopard (Panthera pardus) in a mountainous stretch surrounded by deserts in central Iran. During 6724 camera trap nights, we detected eight and five independent leopards in 2012 and 2016 sessions, respectively. The top performing model demonstrated density estimates of 1.6 (95% CI = 0.9-2.9) and 1.0 (95% CI = 0.6-1.6) independent leopards/100 km2 in 2012 and 2016, respectively. Both sex and season had substantial effects on spatial scale (σ), with larger movements for males and during winter. Currently available estimates in arid regions represent some of the lowest densities across the leopard global range. These small populations are vulnerable to demographic stochasticity. Monitoring temporal changes in population density and composition can inform conservation priorities.

scholarly journals Strain population structure varies widely across bacterial species and predicts strain colonization in unrelated individuals

2020 ◽  
Author(s):  
Jeremiah J. Faith ◽  
Alice Chen-Liaw ◽  
Varun Aggarwala ◽  
Nadeem O. Kaakoush ◽  
Thomas J. Borody ◽  
...  
Keyword(s):  
Population Structure ◽  
Gut Microbiota ◽  
Population Size ◽  
Bacterial Species ◽  
Fecal Microbiota ◽  
Small Population ◽  
Bacterial Strains ◽  
Bacterial Genomes ◽  
Population Sizes ◽  
Microbial Strain

SummaryThe population structure of strains within a bacterial species is poorly defined, despite the functional importance of strain variation in the human gut microbiota on health. Here we analyzed >1000 sequenced bacterial strains from the fecal microbiota of 47 individuals from two countries and combined them with >150,000 bacterial genomes from NCBI to quantify the strain population size of different bacterial species, as well as the frequency of finding the same strain colonized in unrelated individuals who had no opportunities for direct microbial strain transmission. Strain population sizes ranged from tens to over one-hundred thousand per species. Prevalent strains in common gut microbiota species with small population sizes were the most likely to be harbored in two or more unrelated individuals. The finite strain population size of certain species creates the opportunity to comprehensively sequence the entirety of these species’ prevalent strains and associate their presence in different individuals with health outcomes.

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