Conserving declining species using incomplete demographic information: what help can we expect from the use of matrix population models?

2006 ◽  
Vol 56 (4) ◽  
pp. 519-533 ◽  
Author(s):  
Lia Hemerik ◽  
Chris Klok

AbstractDue to human activity, many species have strongly declined in number and are currently threatened with extinction. Management directed at conservation of these species can benefit from the use of simple population models such as matrix models. However, for many species, data on survival and reproduction are scarce. Therefore, we set up a general framework based on a matrix model with three parameters: reproduction, juvenile (=first year survival) and adult survival in which incomplete data can be analysed. This framework is applicable to species that can mature after their first year of life. The point in a calendar year at which the population size is determined, i.e. the census time, is varied. We discuss the differences and the similarities between matrices modelling the same population at different census times. The population growth rate and the elasticity of the survival and reproduction parameters have been determined analytically. From these we made, as a visual diagnostic tool (general framework), plots of the growth rate and the elasticity pattern and their dependence on actual values of the reproduction parameter and the juvenile and adult survival. To illustrate the use of this framework we plot and discuss literature data on survival and/or reproduction of a few bird species with a juvenile stage of one year in the light of our modelling results.

2009 ◽  
Vol 59 (1) ◽  
pp. 127-144 ◽  
Author(s):  
Lia Hemerik ◽  
Chris Klok ◽  
Maja Roodbergen

AbstractMany populations of wader species have shown a strong decline in number in Western-Europe in recent years. The use of simple population models such as matrix models can contribute to conserve these populations by identifying the most profitable management measures. Parameterization of such models is often hampered by the availability of demographic data (survival and reproduction). In particular, data on survival in the pre-adult (immature) stage of wader species that remain in wintering areas outside Europe are notoriously difficult to obtain, and are therefore virtually absent in the literature. To diagnose population decline in the wader species; Black-tailed Godwit, Curlew, Lapwing, Oystercatcher, and Redshank, we extended an existing modelling framework in which incomplete demographic data can be analysed, developed for species with a pre-adult stage of one year. The framework is based on a Leslie matrix model with three parameters: yearly reproduction (number of fledglings per pair), yearly pre-adult (immature) and yearly adult (mature) survival. The yearly population growth rate of these populations and the relative sensitivity of this rate to changes in survival and reproduction parameters (the elasticity) were calculated numerically and, if possible, analytically. The results showed a decrease in dependence on reproduction and an increase in pre-adult survival of the population growth rate with an increase in the duration of the pre-adult stage. In general, adult survival had the highest elasticity, but elasticity of pre-adult survival increased with time to first reproduction, a result not reported earlier. Model results showed that adult survival and reproduction estimates reported for populations of Redshank and Curlew were too low to maintain viable populations. Based on the elasticity patterns and the scope for increase in actual demographic parameters we inferred that conservation of the Redshank and both Curlew populations should focus on reproduction. For one Oystercatcher and the Black-tailed Godwit populations we suggested a focus on both reproduction and pre-adult survival. For the second Oystercatcher population pre-adult survival seemed the most promising target for conservation. And for the Lapwing populations all demographic parameters should be considered.


2010 ◽  
Vol 13 (9) ◽  
pp. 1182-1197 ◽  
Author(s):  
Yvonne M. Buckley ◽  
Satu Ramula ◽  
Simon P. Blomberg ◽  
Jean H. Burns ◽  
Elizabeth E. Crone ◽  
...  

2019 ◽  
Vol 97 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Michael E. Wheeler ◽  
Jeb A. Barzen ◽  
Shawn M. Crimmins ◽  
Timothy R. Van Deelen

Population growth rate in long-lived bird species is often most sensitive to changes in adult survival. Sandhill Cranes (Antigone canadensis (Linnaeus, 1758)) have long life spans, small broods, and delayed first reproduction. Only territorial adult Sandhill Cranes participate in breeding, and territory acquisition reflects the interplay between the availability of suitable territories and the variation in mortality of adult birds occupying those territories. We estimated vital rates of a population at equilibrium using long-term resightings data (2000–2014; n = 451 marked individuals) in a multistate mark–resight model and used a stage-structured projection matrix to assess how strongly territorial adult survival affects population growth rate. Elasticity analysis indicated territorial birds surviving and retaining territories had a 2.58 times greater impact on population growth compared with the next most important transition rate (survival of nonterritorial adults remaining nonterritorial). Knowing how changes in vital rates of various stage classes will differentially impact population growth rate allows for targeted management actions including encouraging growth in recovering populations, assessing opportunity for recreational harvest, or maintaining populations at a desired level. This study also highlights the value of collecting demographic data for all population segments, from which one can derive reproductive output or growth rate.


2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.


2013 ◽  
Vol 82 (6) ◽  
pp. 1117-1119 ◽  
Author(s):  
Salvador Herrando-Pérez

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 432 ◽  
Author(s):  
Melody A. Keena ◽  
Paul M. Moore ◽  
Gregg Bradford

Anoplophora chinensis (Forster) is an invasive species that can damage many tree species in orchard, urban, and forested habitats. Adult survival, reproduction, and egg hatch of A. chinensis from Italy and China are evaluated at eight constant temperatures (5, 10, 15, 20, 25, 30, 35, and 40 °C) under laboratory conditions. The estimated Tmax for longevity was 42 and 33 °C for females and 42 and 39 °C for males from China and Italy, respectively. The estimated Tmax, Tmin, and optimum temperature for fecundity were 35, 9, and 29 °C, respectively. Females laid eggs at 15–30 °C and eggs hatched at 15–35 °C. Days to first oviposition increased exponentially from 13 days at 30 °C to >300 days near 10 °C. The estimated Tmin for egg hatch was 13 °C, the Tmax at 38 °C, and the optimum 29 °C. Percentage hatch was estimated to be highest at 26 °C and have a Tmax of 31 °C and Tmin of 10 °C. These results indicate that summer temperatures over a wide range of latitudes should support beetle survival and reproduction, but at temperatures ≥35 °C, oviposition ceases, and adult survivorship declines. In addition, females may survive into the fall, but lay fewer eggs that may not hatch. These responses of A. chinensis to temperature can be used for developing phenological models to predict the timing of stages for management or eradication efforts.


1986 ◽  
Vol 34 (3) ◽  
pp. 351 ◽  
Author(s):  
A Lill

Estimated expenditures on brood-care by unassisted female superb lyrebirds, obtained through time-energy budgeting, were compared with published values for other bird species. With the exception of nestbuilding, estimated daily expenditures were relatively low, due mainly to the small brood size and low level of parental attentiveness. It is suggested that the traits which reduce daily brood-care expenditures, particularly the small brood size and extremely slow growth rate, may have evolved as adaptations which enabled deserted females operating close to maximal capacity to cope with single-parenting. Male parental involvement could probably increase the growth rate of the young, but not brood size; moreover, egg- laying was sufficiently asynchronous to afford multiple mating opportunities to parentally emancipated males. However, the slow growth rate of the young results in relatively large overall brood-care expenditures for females. Investments by males of up to 50% of daylight hours and 45% of BMR on singing at the height of the mating season were comparable with those of partially emancipated, polygynous males of other species. They probably reflect the high level of competition to control good display areas and to advertise status and quality to widely spaced females.


Author(s):  
Generoso Abes

Consultants and more senior co-resident physicians at the Philippine General Hospital (PGH) would call him “Caloy.” Hardly would I hear anybody (including our ENT department secretary) address him as Dr. Reyes. This was not because he was not a respected faculty member. Rather, he was everybody’s friend and he probably preferred to be addressed by his nickname. Dr. Carlos P. Reyes was a tall, friendly guy, easily recognizable while walking through the short PGH corridor stretching from the old ENT Ward (Ward 3) to the old ENT operating room (OR) called Floor 15, later designated as the PGH Nursing Office. He would almost always be holding either an expensive photography camera, electronic gadget, ENT OR instrument, or car magazines – suggesting his varied interests aside from having good knowledge of Otolaryngology, particularly Otology. He would usually stop and chat with an acquaintance about his new medical or non-medical interests. I first met Dr. Caloy when I was the first year resident assigned to the Otology section. He would call me “Ging” while presenting the ear patients at the outpatient department (OPD) Ear Clinic, only to learn later that he would address all unfamiliar persons by that name. He was kind, helpful and very understanding. Equipped with ample information in Otology he gathered from postgraduate studies abroad, he would selflessly share these with the residents in order to sharpen our diagnostic acumen. He would instruct us to rely on concise yet complete clinical examination, involving audiologic evaluation tools and meager radiologic information in considering differential diagnoses. He was quite willing to assist us in our learning processes, particularly on how to distinguish middle ear from inner ear disorders, and cochlear versus retrocochlear diseases. Since we did not have any audiologist at that time, he admonished us to carry out the needed audiometric evaluations on our ear patients ourselves in order to learn both the techniques of the procedures and their limitations. Hence, after the OPD clinic we would not only perform routine pure tone and speech audiometric tests but also special examinations like the Bekesy test, short increment sensitivity index (SISI) test, alternate binaural loudness balance (ABLB) test and the test for tone decay. We would then discuss the test results during our next ear clinic and we would listen and be amazed at how Dr. Caloy would integrate the information and arrive at the complex diagnosis. Dr. Caloy was our mentor at the time when refinements in tympanoplasty and mastoidectomy aroused the excitement and imagination of budding otologists worldwide. Whereas canal down mastoidectomy was the usual norm to safely remove common mastoid pathology like cholesteatoma, Dr. Caloy introduced the concept of intact canal wall mastoidectomy that avoids or mitigates recurrent postoperative cleaning of the mastoid bone. The period was also the dawn of neuro-otology when Dr. William House popularized the transmastoid approach for acoustic neuroma and the endolymphatic mastoid shunt as treatment for Meniere’s disease. In order to teach us the anatomical and surgical principles of performing these procedures, Dr. Caloy set up the first temporal bone dissection laboratory in the country at the mezzanine above the ENT conference room. He would offer the course to all ENT residents-in-training and consultants nationwide. He practically revolutionized the method of otologic surgery by requiring ENT surgeons to practice doing ear surgery in the temporal bone dissection lab prior to performing ear surgeries in the operating room. In addition, he advocated the use of the operating microscope and dental drills in place of the old bone gouges, chisels and bone ronguers. His ideas were later adopted by other ENT training institutions as we see today. The requirement that every ENT resident must undergo temporal bone dissection in the course of his training obviously stemmed from the efforts of Dr. Caloy. Many senior ENT consultants who are still with us today were former students of Dr. Caloy in his temporal bone lab Unfortunately, before finishing my residency training, Dr Caloy expeditiously left the PGH ENT department for unknown reasons. He then set up his private clinic in Quezon City and later joined the ENT department of University of Santo Tomas. Reflecting on the significant yet probably unknown achievements of Dr. Caloy toward the advancement of otology and neuro-otology in our country, I realize how blessed I was to be one of his students during that brief period when he was still with us at UP-PGH. With our profound gratitude Sir, we will always remember you.


Sign in / Sign up

Export Citation Format

Share Document