ESTIMATION OF COCCINELLID NUMBERS AND MOVEMENT IN THE FIELD

AbstractChanges in the numbers of adults of Coccinella californica Mannerheim and C. trifasciata Mulsant in small plots of alfalfa and oats were monitored over the summers of 1974 and 1975 by mark–recapture methods. Aphid population dynamics in the plots were studied concurrently. In the second summer, movements of the beetles were also monitored by means of individual marking and sticky net traps. Approximately 1000 beetles of each species were marked in the first summer; in the second, roughly 5000 and 3000 respectively. The capture–recapture method was tested with a caged population, and was found to be feasible for estimation of the coccinellid numbers. Catch per unit effort, using visual sampling that was not dependent on marking, provided an acceptable index of numbers which could give population estimates when calibrated against mark–recapture estimates.The number of beetles trapped on the sticky nets was primarily a function of numbers in the plots and temperature, with the two species having different relationships between temperature and flight. But for C. californica, the numbers trapped were also a function of aphid density in the plots; the data suggested that for C. trifasciata the same is probably true, but the range of densities of pea aphids was too narrow to show it. In both seasons, C. trifasciata was predominant in the alfalfa and C. californica in the oats. Plot to plot movements by overwintered beetles reflected the same apparent preference. Changes in the numbers of coccinellids in the experimental plots, and their reproductive success, are discussed in the light of these findings.

Download Full-text

An open spatial capture–recapture model for estimating density, movement, and population dynamics from line‐transect surveys

Ecology and Evolution ◽

10.1002/ece3.7566 ◽

2021 ◽

Author(s):

Timothy A. Gowan ◽

Nathan J. Crum ◽

Jason J. Roberts

Keyword(s):

Population Dynamics ◽

Line Transect ◽

Capture Recapture

Download Full-text

Predicting harvest of non-native signal crayfish in lakes — a role for changing climate?

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2015-0241 ◽

2016 ◽

Vol 73 (5) ◽

pp. 785-792 ◽

Cited By ~ 3

Author(s):

Patrik Bohman ◽

Lennart Edsman ◽

Alfred Sandström ◽

Per Nyström ◽

Marika Stenberg ◽

...

Keyword(s):

Population Dynamics ◽

Water Temperature ◽

Temperature Data ◽

Adult Survival ◽

Winter Mortality ◽

Freshwater Crayfish ◽

Catch Per Unit Effort ◽

Signal Crayfish ◽

Cool Water ◽

Air Temperatures

The signal crayfish (Pacifastacus leniusculus) was introduced to Sweden in 1960, and it has a high commercial and recreational value, but it may also have negative effects on native ecosystems. To better predict how climate warming will affect population dynamics of this cool-water crayfish, we explored the role of temperature and density dependence as explanatory factors of the subsequent years’ catch rates of commercially sized signal crayfish in four Swedish lakes. We found air temperatures to be good proxies for water temperatures in all lakes, except during winter. We could only obtain water temperature data for Lake Vättern, and winter temperature data were therefore only included in the analysis of catch-per-unit-effort patterns in this lake. Our results indicate that increasing mean air temperatures will potentially affect the population dynamics of cool-water freshwater crayfish species such as the signal crayfish. Based on data from four lakes, it seems that the population dynamics of signal crayfish are lake-specific and could be affected by either recruitment during the juvenile stage, the survival and growth of adults, or both. Increased fluctuations in water temperature during winter may potentially influence adult survival. To better predict the effects of global warming on the dynamics of cool-water crayfish populations, we suggest that future studies should investigate recruitment in crayfish along temperature gradients and the influence of variations in water temperature on winter mortality.

Download Full-text

Absolute Population Estimates Using Capture–Recapture Experiments

Southwood's Ecological Methods ◽

10.1093/oso/9780198862277.003.0003 ◽

2021 ◽

pp. 63-112

Author(s):

Peter A. Henderson

Keyword(s):

Robust Design ◽

Linear Method ◽

Stochastic Method ◽

Population Estimates ◽

Protein Marking ◽

Capture Recapture ◽

Estimate Population Size ◽

Log Linear ◽

Absolute Population ◽

Natural Marks

The main methods used to estimate population size using capture–recapture for both closed and open populations are described, including the Peterson–Lincoln estimator, the Schabel census, Bailey’s triple catch, the Jolly–Seber stochastic method, and Cormack’s log-linear method. The robust design approach is described. R code listings for commonly used packages are presented. The assumptions common to capture–recapture methods are reviewed, and tests for assumptions such as equal catchability described. The use of programs to select model assumptions are described. The main methods for marking different animal groups are described, together with the use of natural marks and parasites and DNA. Marking methods include paint marks, dyes, tagging, protein marking, DNA, natural marks, tattooing, and mutilation. Methods for handling and release are described.

Download Full-text

Conservation, Ecology, and Management of Catfish: The Second International Symposium

Conservation, Ecology, and Management of Catfish: The Second International Symposium ◽

10.47886/9781934874257.ch12 ◽

2011 ◽

Keyword(s):

Population Dynamics ◽

Channel Catfish ◽

Mississippi River ◽

Upper Mississippi River ◽

Catch Per Unit Effort ◽

Blue Catfish ◽

Resource Monitoring ◽

Flathead Catfish ◽

Unit Effort ◽

Catch Rates

Abstract.—Using Long Term Resource Monitoring Program data collected from impounded (Pool 26) and unimpounded (Open River) reaches of the upper Mississippi River, we investigated population dynamics of flathead catfish Pylodictis olivaris, channel catfish Ictalurus punctatus, and blue catfish I. furcatus from random sites located in side channel border (SCB) and main channel border (MCB) habitats. Objectives were to (1) compare trends (1993–2007) of three catfishes collected in Pool 26 and Open River reaches of the upper Mississippi River, and (2) provide needed information to managers on population dynamics through time using a binary gear approach of active (i.e., daytime electrofishing) and passive gears (hoopnetting). Active gears resulted in a higher catch per unit effort (CPUE) of all catfishes in each habitat–reach combination as compared to passive gears. Passive gears resulted in negligible catches of blue catfish and flathead catfishes (e.g., mean of <1 fish/net night). Catch per unit effort using active gear resulted in a greater number of channel catfish captured in Pool 26 compared to the Open River, with Open River SCB habitat having the lowest CPUE in most years. Blue catfish in the Open River had a higher CPUE using active gear as compared to Pool 26, with the Open River MCB having the greatest CPUE. Flathead catfish had a higher CPUE in MCB habitat compared to SCB habitat, with the Open River MCB having the highest CPUE in most years. However, declining trends in flathead catfish appears to be occurring in Open River habitats while trends in flathead catfish appear to be slightly increasing in Pool 26. The most common length-classes captured were substock and stock-sized fish regardless of habitat, species, or reach. Trends for channel catfish were easily determined due to high catch rates; however, more monitoring and enhanced sampling is needed to accurately assess flathead catfish and blue catfish trends and to accurately determine demographics for all three species.

Download Full-text

Sex‐specific population dynamics of ocelots in Belize using open population spatial capture–recapture

Ecosphere ◽

10.1002/ecs2.2792 ◽

2019 ◽

Vol 10 (7) ◽

Cited By ~ 3

Author(s):

Christopher B. Satter ◽

Ben C. Augustine ◽

Bart J. Harmsen ◽

Rebecca J. Foster ◽

Marcella J. Kelly

Keyword(s):

Population Dynamics ◽

Specific Population ◽

Open Population ◽

Capture Recapture

Download Full-text

Breeding transients in capture–recapture modeling and their consequences for local population dynamics

Scientific Reports ◽

10.1038/s41598-020-72778-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Daniel Oro ◽

Daniel F. Doak

Keyword(s):

Growth Rate ◽

Population Dynamics ◽

Population Growth ◽

Population Growth Rate ◽

Local Population ◽

Environmental Stochasticity ◽

Adult Survival ◽

Local Survival ◽

First Reproduction ◽

Capture Recapture

Abstract Standard procedures for capture–mark–recapture modelling (CMR) for the study of animal demography include running goodness-of-fit tests on a general starting model. A frequent reason for poor model fit is heterogeneity in local survival among individuals captured for the first time and those already captured or seen on previous occasions. This deviation is technically termed a transience effect. In specific cases, simple, uni-state CMR modeling showing transients may allow researchers to assess the role of these transients on population dynamics. Transient individuals nearly always have a lower local survival probability, which may appear for a number of reasons. In most cases, transients arise due to permanent dispersal, higher mortality, or a combination of both. In the case of higher mortality, transients may be symptomatic of a cost of first reproduction. A few studies working at large spatial scales actually show that transients more often correspond to survival costs of first reproduction rather than to permanent dispersal, bolstering the interpretation of transience as a measure of costs of reproduction, since initial detections are often associated with first breeding attempts. Regardless of their cause, the loss of transients from a local population should lower population growth rate. We review almost 1000 papers using CMR modeling and find that almost 40% of studies fitting the searching criteria (N = 115) detected transients. Nevertheless, few researchers have considered the ecological or evolutionary meaning of the transient phenomenon. Only three studies from the reviewed papers considered transients to be a cost of first reproduction. We also analyze a long-term individual monitoring dataset (1988–2012) on a long-lived bird to quantify transients, and we use a life table response experiment (LTRE) to measure the consequences of transients at a population level. As expected, population growth rate decreased when the environment became harsher while the proportion of transients increased. LTRE analysis showed that population growth can be substantially affected by changes in traits that are variable under environmental stochasticity and deterministic perturbations, such as recruitment, fecundity of experienced individuals, and transient probabilities. This occurred even though sensitivities and elasticities of these parameters were much lower than those for adult survival. The proportion of transients also increased with the strength of density-dependence. These results have implications for ecological and evolutionary studies and may stimulate other researchers to explore the ecological processes behind the occurrence of transients in capture–recapture studies. In population models, the inclusion of a specific state for transients may help to make more reliable predictions for endangered and harvested species.

Download Full-text

Marked Cards in the Pack: Using Playing Cards to Teach the Importance of Sample Size & Testing Assumptions in Capture–Recapture Estimations of Population Size

The American Biology Teacher ◽

10.1525/abt.2020.82.6.396 ◽

2020 ◽

Vol 82 (6) ◽

pp. 396-401

Author(s):

Michael Calver ◽

Timothy Blake

Keyword(s):

Secondary School ◽

Sample Size ◽

Population Size ◽

Confidence Intervals ◽

Population Ecology ◽

Simple Approach ◽

Population Estimates ◽

Index Method ◽

Capture Recapture ◽

Approach To Teaching

Estimating population size is essential for many applications in population ecology, so capture–recapture techniques to do this are often taught in secondary school classrooms and introductory university units. However, few classroom simulations of capture–recapture consider the sensitivity of results to sampling intensity, the important concept that the population size calculated is an estimate with error attached, or the consequences of violating assumptions underpinning particular capture–recapture models. We describe a simple approach to teaching the Lincoln index method of capture–recapture using packs of playing cards. Students can trial different sampling intensities, calculate 95% confidence intervals for population estimates, and explore the consequences of violating specific assumptions.

Download Full-text

Estimating brush-tailed rock-wallaby population size using individual animal recognition

Australian Mammalogy ◽

10.1071/am11005 ◽

2011 ◽

Vol 33 (2) ◽

pp. 228

Author(s):

Karl Vernes ◽

Stuart Green ◽

Piers Thomas

Keyword(s):

Population Size ◽

National Park ◽

New South ◽

Morphological Characters ◽

Population Estimates ◽

Individual Animal ◽

Mark Recapture ◽

South Wales ◽

North Eastern ◽

Estimate Population Size

We undertook surveys of brush-tailed rock-wallabies (Petrogale penicillata) at four colonies in Oxley Wild Rivers National Park, north-eastern New South Wales, with the aim of developing a technique based upon individual animal recognition that could be used to obtain robust population estimates for rock-wallaby colonies. We identified individuals on the basis of distinct morphological characters in each colony using visual observations, and used the data within a ‘mark–recapture’ (or sight–resight) framework to estimate population size. More than 37 h of observations were made over 10 sampling days between 18 May and 9 June 2010. We could identify 91.7% of all rock-wallabies that were independently sighted (143 of 156 sightings of 35 animals). A small percentage of animals could not be identified during a visit because they were seen only fleetingly, were in dense cover, or were partly obscured by rock. The number of new animals sighted and photographed declined sharply at the midpoint of the survey, and there was a corresponding increase in resighting of known individuals. Population estimates using the mark–recapture methodology were nearly identical to estimates of total animals seen, suggesting that this method was successful in obtaining a complete census of rock-wallabies in each colony.

Download Full-text

Population Estimates from Orbital Data of Medium Spatial Resolution: Applications for a Brazilian Municipality

Sustainability ◽

10.3390/su12093565 ◽

2020 ◽

Vol 12 (9) ◽

pp. 3565

Author(s):

Járvis Campos ◽

José Irineu Rangel Rigotti ◽

Emerson Augusto Baptista ◽

Antônio Miguel Vieira Monteiro ◽

Ilka Afonso Reis

Keyword(s):

Population Dynamics ◽

Environmental Planning ◽

External Validation ◽

Population Estimates ◽

Internal Validation ◽

Small Areas ◽

Explanatory Variables ◽

Spectral Bands ◽

Landsat 7 ◽

Orbital Data

In recent decades, there has been an increase in the search for more detailed information on population dynamics, given the growing demand for more sustainable economic, social, and environmental planning. The dissemination of Geographic Information Systems (GIS) has contributed to the development of methodologies for the field of population estimates for small areas. To support more sustainable policies, this study aims to evaluate the capacity and contribution of the orbital images (Landsat ETM+) for the production of post-census population estimates for the municipality of Contagem, Minas Gerais, Brazil. Firstly, models were built using the average of the reflectance of the spectral bands of the Landsat 7 ETM+ for each special intra-municipal unit, called the census sector, as explanatory variables for the population density. Secondly, this study constructed models that use the reflectance and the distributed population at the level of the pixels of the images. All models were tested through internal validation procedures, external validation, and comparative analyses with post-census estimates. Internal validation presented excellent results (below 7%), while in external validation, the method at the level of the pixels presented consistent results, below 1% relative error. These results provide useful clues and can help policymakers in the development of more sustainable and effective public policies, insofar as population estimates are extremely important for the planning of any society.

Download Full-text