Improving management strategies for the red fox by using projection matrix analysis

2001 ◽  
Vol 28 (4) ◽  
pp. 333 ◽  
Author(s):  
S. R. McLeod ◽  
G. R. Saunders
Keyword(s):  
Red Fox ◽  
Management Strategies ◽  
Fertility Control ◽  
Projection Matrix ◽  
Matrix Analysis ◽  
Elasticity Analysis ◽  
Age Classes ◽  
Finite Rate ◽  
Relative Contribution ◽  
Rate Of Increase

The absolute and relative contribution to the finite rate of increase of specific age classes was examined using projection matrix sensitivity and elasticity analysis for a number of red fox (Vulpes vulpes) populations. The fox populations that were examined included urban foxes from England, rural foxes from North America and rural foxes from Australia. The youngest age classes made the greatest contribution to the finite rate of increase for all populations studied. A pest management strategy that reduces survivorship and fertility of juvenile and young adult foxes (Age Classes 1 and 2) will be the most effective strategy for reducing a population’s finite rate of increase. The results indicate that fertility control may be as effective as lethal methods for controlling some fox populations.

Biotic interactions and the population dynamics of the long-lived columnar cactus Neobuxbaumia tetetzo in the Tehuacán Valley, Mexico

1999 ◽  
Vol 77 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Héctor Godínez-Alvarez ◽  
Alfonso Valiente-Banuet ◽  
Leopoldo Valiente Banuet
Keyword(s):  
Population Dynamics ◽  
Matrix Models ◽  
Biotic Interactions ◽  
Positive Interactions ◽  
Elasticity Analysis ◽  
Finite Rate ◽  
Tehuacán Valley ◽  
Columnar Cactus ◽  
Tehuacan Valley ◽  
Rate Of Increase

The giant columnar cactus Neobuxbaumia tetetzo (Coulter) Backeberg is the dominant species of a vegetation type locally called "tetechera" that occupies ca. 400 km2 in the Tehuacán Valley. As a way to analyse the role of biotic interactions on the population dynamics of this species, we conducted an elasticity analysis, using matrix models elaborated from field data, to determine the finite rate of increase and the critical stages of the life cycle that were related to the biotic interactions occurring during these stages. Although the estimated finite rate of increase did not differ from unity there were significant differences between the actual and predicted size distributions. Elasticity analysis showed that survivorship was the most important life-history parameter to the finite rate of increase. Because survivorship depends on the presence of nurse plants, our results emphasise the importance of positive interactions on the population dynamics of long-lived columnar cacti.Key words: biotic interactions, Cactaceae, deserts, matrix models, population dynamics.

scholarly journals Simulating the next steps in badger control for bovine tuberculosis in England

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248426
Author(s):  
Graham C. Smith ◽  
Richard Budgey
Keyword(s):  
Simulation Model ◽  
Carrying Capacity ◽  
Bovine Tuberculosis ◽  
Management Strategies ◽  
Fertility Control ◽  
Host Population ◽  
Dramatic Reduction ◽  
Control Option ◽  
Badger Vaccination ◽  
The Uk

Industry-led culling of badgers has occurred in England to reduce the incidence of bovine tuberculosis in cattle for a number of years. Badger vaccination is also possible, and a move away from culling was “highly desirable” in a recent report to the UK government. Here we used an established simulation model to examine badger control option in a post-cull environment in England. These options included no control, various intermittent culling, badger vaccination and use of a vaccine combined with fertility control. The initial simulated cull led to a dramatic reduction in the number of infected badgers present, which increased slowly if there was no further badger management. All three approaches led to a further reduction in the number of infected badgers, with little to choose between the strategies. We do note that of the management strategies only vaccination on its own leads to a recovery of the badger population, but also an increase in the number of badgers that need to be vaccinated. We conclude that vaccination post-cull, appears to be particularly effective, compared to vaccination when the host population is at carrying capacity.

scholarly journals Genome-wide markers reveal differentiation between and within the cryptic sister species, sunset and vermilion rockfish

2021 ◽  
Author(s):  
Gary C. Longo ◽  
John Harms ◽  
John R. Hyde ◽  
Matthew T. Craig ◽  
Ana Ramón-Laca ◽  
...  
Keyword(s):  
Management Strategies ◽  
Cost Effective ◽  
Sister Species ◽  
Nucleotide Polymorphisms ◽  
Relative Contribution ◽  
Genetic Groups ◽  
Cost Effective Method ◽  
Species Population ◽  
Single Complex ◽  
Species Specific

AbstractThe vermilion rockfish complex, which consists of the cryptic sister species vermilion and sunset rockfish, is one of the most valuable recreational fisheries on the U.S. West Coast. These species are currently managed as a single complex, and because of uncertainty surrounding the relative contribution of each species within existing data sources, the stock status of each species is not fully known. A reliable and cost-effective method is needed to disentangle these species that will allow for the development of abundance indices, life history profiles, and catch histories that may potentially support species-specific stock assessments. Using restriction-site associated DNA sequence (RADseq) markers we generated 10,003 polymorphic loci to characterize the vermilion rockfish complex. PCA and Bayesian clustering approaches based on these loci clearly distinguished between sunset and vermilion rockfishes and identified hybrid individuals. These loci included 203 highly differentiated (FST ≥ 0.99) single nucleotide polymorphisms, which we consider candidates in the planned development of a diagnostic assay capable of distinguishing between these cryptic species. In addition to clearly delineating to species, subsets of the interspecific markers allowed for insight into intraspecific differentiation in both species. Population genetic analyses for sunset rockfish identified two weakly divergent genetic groups with similar levels of genetic diversity. Vermilion rockfish, however, were characterized by three distinct genetic groups with much stronger signals of differentiation and significantly different genetic diversities. Collectively, these data will contribute to well-informed, species-specific management strategies to protect this valuable species complex.

scholarly journals Using osteological measurements to estimate body length in Amazonian manatees

2021 ◽  
Vol 51 (2) ◽  
pp. 156-161
Author(s):  
Gisele de Castro Maciel VALDEVINO ◽  
Vera Maria Ferreira DA SILVA ◽  
Rodrigo de Souza AMARAL
Keyword(s):  
Body Length ◽  
Management Strategies ◽  
Age Groups ◽  
The Body ◽  
Simple Linear Regression ◽  
Age Classes ◽  
Linear Measurements ◽  
Behavioral Studies ◽  
Condylobasal Length

ABSTRACT Body length is an important parameter in morphological, ecological and behavioral studies of a species and contributes to the understanding of the body condition of individuals. This parameter is essential for conservation and management strategies by informing studies evaluating growth rates, physical maturity and classification of individuals into age groups, promoting better accuracy for the biological parameters of the species. The aim of this study was to identify predictors of body length for Amazonian manatees (Trichechus inunguis) using metric characters of osteological materials. Eleven linear measurements of skull, jaw, scapulae and humeri were collected from 41 Amazonian manatee skeletons of different age classes (calf, juvenile and adult). Data were analyzed by simple linear regression. The condylobasal length was the best predictor of body length for the species (R = 0.943), however, all bones evaluated showed at least one measurement with the capacity to predict body size (R2 > 0.9). Results of this study are useful for inferring body length of Amazonian manatees using bones deposited in museums and biological collections, expanding the informative potential of these materials.

Biology, Management, and Protection of North American Sturgeon

2002 ◽  
Keyword(s):  
Population Growth ◽  
Life Histories ◽  
Habitat Restoration ◽  
Negative Impact ◽  
Elasticity Analysis ◽  
Age Classes ◽  
Adult Age ◽  
Significant Negative Impact ◽  
Young Of The Year ◽  
Restoration Strategies

Abstract.— We use elasticity analyses for three sturgeon species, the shortnose sturgeon <em>Acipenser brevirostrum</em>, Atlantic sturgeon <em>A. oxyrinchus</em>, and white sturgeon <em>A. transmontanus</em>, to calculate the potential to increase population growth rate, λ, by improving survival and fecundity. Elasticity analysis is a means of assessing changes to λ resulting from conservation initiatives. The elasticity of λ to survival has a characteristic profile that includes a plateau of high elasticity values across the young of the year and the juvenile ages. However, survival elasticity falls at maturity and declines rapidly with increasing adult age. Changes to fecundity have relatively little impact; the total of the fecundity elasticities over all ages is equal to the single young-of-the-year survival elasticity. Even though the young-of-the-year survival elasticity is equal to that of any other juvenile age, the overall opportunity for affecting λ; is strongest in the young-of-the-year age-class because of its exceptional potential for increase to survival. The juvenile and adult stages have roughly equal total survival elasticities. These findings are particularly relevant in understanding the contributions of hatcheries, harvest regulations and habitat restoration as strategies for sturgeon conservation. Hatcheries are focused on the young of the year, the demographically most sensitive component of sturgeon life histories, and thus have the potential to make significant increases to λ if the genetic, evolutionary and ecological impacts of hatcheries can be controlled. Harvest, even at low levels, can have a significant negative impact on λ when it affects multiple age classes. Managers can use elasticity analysis to calculate the total impact of harvest and to mathematically evaluate the trade-off in exploiting young versus older individuals. Habitat restoration strategies, usually assessed in terms of survivals of the age classes impacted, would also benefit from using elasticity analysis to interpret their contributions to l. If restoration efforts target the survival of age classes with high elasticities, significant population growth may be achieved.

BIONOMICS OF BLATTISOCIUS KEEGANI (FOX) (ACARINA: ASCIDAE), A PREDATOR ON EGGS OF PESTS OF STORED GRAINS

1967 ◽  
Vol 45 (6) ◽  
pp. 1093-1099 ◽  
Author(s):  
Philip S. Barker
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Female Offspring ◽  
Finite Rate ◽  
Rate Of Increase ◽  
Stored Grains ◽  
History Of ◽  
Cryptolestes Turcicus

The life history of Blattisocius keegani (Fox) was studied at 60, 72, and 80 °F, and at relative humidities (r.h.) of 70 to 75% and 95 to 100%. A life cycle of 6 to 7 days was found at 80 °F. Oviposition was studied at 80 °F and 70 to 75% r.h.; the finite rate of increase (λ) was 3.33 female offspring per female per week. Approximately three Cryptolestes turcicus (Grouvelle) eggs were required to rear one B. keegani to adulthood at 80 °F and 70 to 75% r.h. Female B. keegani that consumed one C. turcicus egg per day were able to oviposit. The hosts investigated included eggs of six species of beetles, and two species of mites that infest stored grains.

The response of a predator, Hypoaspis aculeifer (Canestrini) (Acarina:Laelapidae), to two species of prey

1969 ◽  
Vol 47 (3) ◽  
pp. 343-345 ◽  
Author(s):  
Philip S. Barker
Keyword(s):  
Prey Species ◽  
Tyrophagus Putrescentiae ◽  
Finite Rate ◽  
Hypoaspis Aculeifer ◽  
Rate Of Increase

The effect of two prey species, Tyrophagus putrescentiae (Schrank) and Glycyphagus domesticus (de Geer), on the oviposition of the predator Hypoaspis aculeifer (Canestrini) was studied. The H. aculeifer females fed on T. putrescentiae laid more eggs and lived longer than those fed on G. domesticus. Predators fed on G. domesticus laid more eggs per day and had a shorter mean generation than predators fed on T. putrescentiae. The greatest finite rate of increase of H. aculeifer was obtained when G. domesticus was the prey.

scholarly journals Could current fertility control methods be effective for landscape-scale management of populations of wild horses (Equus caballus) in Australia?

2018 ◽  
Vol 45 (3) ◽  
pp. 195 ◽  
Author(s):  
Rebecca J. Hobbs ◽  
Lyn A. Hinds
Keyword(s):  
Population Growth ◽  
Population Size ◽  
National Parks ◽  
Fertility Control ◽  
Management Approach ◽  
Attractive Alternative ◽  
Control Methods ◽  
Animal Populations ◽  
Rate Of Increase

Context Fertility control is seen as an attractive alternative to lethal methods for control of population size and genetic diversity in managed animal populations. Immunocontraceptive vaccines have emerged as the most promising agents for inducing long-term infertility in individual animals. However, after over 20 years of scientific testing of immunocontraceptive vaccines in the horse, the scientific consensus is that their application as a sole management approach for reducing population size is not an effective strategy. Aims The purpose of this review is to evaluate currently available non-lethal fertility-control methods that have been tested for their contraceptive efficacy in Equidae, and to assess their suitability for effective management of wild (feral) horses in an Australian setting. Key results (1) Fertility-control agents, particularly injectable immunocontraceptive vaccines based on porcine zona pellucida (PZP) or gonadotrophin-releasing hormone (GnRH), can induce multi-year infertility (up to 3 years) in the horse. Some formulations require annual or biennial booster treatments. Remote dart delivery (on foot) to horses is possible, although the efficacy of this approach when applied to large numbers of animals is yet to be determined. (2) The proportion of females that must be treated with a fertility-control agent, as well as the frequency of treatment required to achieve defined management outcomes (i.e. halting population growth in the short term and reducing population size in the long term) is likely to be >50% per annum. In national parks, treatment of a large number of wild horses over such a broad area would be challenging and impractical. (3) Fertility control for wild horses could be beneficial, but only if employed in conjunction with other broad-scale population-control practices to achieve population reduction and to minimise environmental impacts. Conclusions In Australia, most populations of wild horses are large, dispersed over varied and difficult-to-access terrain, are timid to approach and open to immigration and introductions. These factors make accessing and effectively managing animals logistically difficult. If application of fertility control could be achieved in more than 50% of the females, it could be used to slow the rate of increase in a population to zero (2–5 years), but it will take more than 10–20 years before population size will begin to decline without further intervention. Thus, use of fertility control as the sole technique for halting population growth is not feasible in Australia.

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