Artykuły w czasopismach: „Population decline”

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Wright, Kevin, Lee Berger, Donald K. Nichols, Rick Speare, Michael J. Sredl, Alan Pessier i Bob Johnson. "Amphibian Population Decline". Journal of Herpetological Medicine and Surgery 11, nr 2 (styczeń 2001): 14–27. http://dx.doi.org/10.5818/1529-9651.11.2.14.

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Collen, Ben, Louise McRae, Stefanie Deinet, Adriana De Palma, Tharsila Carranza, Natalie Cooper, Jonathan Loh i Jonathan E. M. Baillie. "Predicting how populations decline to extinction". Philosophical Transactions of the Royal Society B: Biological Sciences 366, nr 1577 (12.09.2011): 2577–86. http://dx.doi.org/10.1098/rstb.2011.0015.

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Global species extinction typically represents the endpoint in a long sequence of population declines and local extinctions. In comparative studies of extinction risk of contemporary mammalian species, there appear to be some universal traits that may predispose taxa to an elevated risk of extinction. In local population-level studies, there are limited insights into the process of population decline and extinction. Moreover, there is still little appreciation of how local processes scale up to global patterns. Advancing the understanding of factors which predispose populations to rapid declines will benefit proactive conservation and may allow us to target at-risk populations as well as at-risk species. Here, we take mammalian population trend data from the largest repository of population abundance trends, and combine it with the PanTHERIA database on mammal traits to answer the question: what factors can be used to predict decline in mammalian abundance? We find in general that environmental variables are better determinants of cross-species population-level decline than intrinsic biological traits. For effective conservation, we must not only describe which species are at risk and why, but also prescribe ways to counteract this.

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Vignieri, Sacha. "Hunting and population decline". Science 363, nr 6432 (14.03.2019): 1188.4–1189. http://dx.doi.org/10.1126/science.363.6432.1188-d.

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Djurdjev, Branislav. "Challenges of population decline". Zbornik Matice srpske za drustvene nauke, nr 121 (2006): 11–17. http://dx.doi.org/10.2298/zmsdn0621011d.

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The paper points out advantages and limitations of contemporary age-structural transition. Age-structural transition may create favorable conditions for fulfillment of millennium development goals, However, it cannot create sustainable demographic development and remove danger of extinction of some nations. The only remedy is family planning program and huge financial resources that will support it for a long period of time.

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AMBROSINI, ROBERTO, DIEGO RUBOLINI, PAOLA TROVÒ, GIOVANNI LIBERINI, MARCO BANDINI, ANDREA ROMANO, BEATRICE SICURELLA, CHIARA SCANDOLARA, MARIA ROMANO i NICOLA SAINO. "Maintenance of livestock farming may buffer population decline of the Barn Swallow Hirundo rustica". Bird Conservation International 22, nr 4 (19.07.2012): 411–28. http://dx.doi.org/10.1017/s0959270912000056.

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SummaryPopulations of farmland and long-distance migratory birds have suffered steep, often dramatic, declines in the last few decades. The Barn Swallow Hirundo rustica is a small migratory farmland bird that breeds synanthropically in farms, particularly where livestock is reared. Populations of this species have suffered marked declines in different parts of its European breeding range. Here, we first report a dramatic decline of 8.4% per year of the number of breeding pairs and the extinction of 19.6% of the colonies in three agricultural areas in Northern Italy, which differ in general ecological conditions. This decline was estimated on a very large sample of 190 randomly chosen farms where breeding pairs were censused both in 2001 and 2010, and occurred at different rates in the three study areas. Barn Swallows declined most (9.3% per year) in an intensively cultivated area where colonies are widespread, and least (1.3% per year) in a hilly area with a comparatively small density of colonies. Variation in livestock farming significantly influenced population dynamics. Specifically, cessation of livestock farming at a given farm between the two census years resulted in a significantly steeper decline in the number of breeding pairs compared to farms where livestock farming was maintained. Our findings highlight the fact that European populations of Barn Swallows breeding in intensively cultivated agro-ecosystems may become significantly depleted in the next decades, and indicate that maintenance of livestock farming may contribute to buffering the population decline of this species.

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Koons, David N., i Jay J. Rotella. "Have Lesser Scaup, Aythya affinis, Reproductive Rates Declined in Parkland Manitoba?" Canadian Field-Naturalist 117, nr 4 (1.10.2003): 582. http://dx.doi.org/10.22621/cfn.v117i4.827.

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Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline.

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Lamb, Robert J., i Patricia A. MacKay. "Seasonal dynamics of a population of the aphid Uroleucon rudbeckiae (Hemiptera: Aphididae): implications for population regulation". Canadian Entomologist 149, nr 3 (29.12.2016): 300–314. http://dx.doi.org/10.4039/tce.2016.58.

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AbstractMany aphid species (Hemiptera: Aphididae) that feed on herbaceous crops exhibit a rise and then sudden decline in abundance. Data from a nine-year study of Uroleucon rudbeckiae (Fitch) on Rudbeckia laciniata Linnaeus (Asteraceae) are used to investigate this pattern of seasonal abundance in a non-agricultural aphid. Aphids on a population of tagged and numbered flower stems were counted weekly. Abundance (mean aphids per stem) was partitioned into prevalence (proportion of stems colonised) and mean intensity (aphids per colonised stem), and also considered as the sum of the aphids in individual colonies. Abundance rose in mid-summer to late summer and then declined, peaking between the end of July and mid-September, earlier in years when the peak was higher. Prevalence showed a more uniform and consistent peak than mean intensity. Most of the 949 colonies were small and short-lived, but a small proportion were long-lived and reached 1000 aphids. Large colonies declined more slowly than moderately-sized colonies. Severe weather, shortening day-length, decline in host quality, density-dependent effects on rate of increase, and emigration failed to explain the population decline. An early rise and later decline in immigration, in conjunction with increasing predation through the summer, were consistent with the decline.

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Reading, C. J., L. M. Luiselli, G. C. Akani, X. Bonnet, G. Amori, J. M. Ballouard, E. Filippi, G. Naulleau, D. Pearson i L. Rugiero. "Are snake populations in widespread decline?" Biology Letters 6, nr 6 (9.06.2010): 777–80. http://dx.doi.org/10.1098/rsbl.2010.0373.

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Long-term studies have revealed population declines in fishes, amphibians, reptiles, birds and mammals. In birds, and particularly amphibians, these declines are a global phenomenon whose causes are often unclear. Among reptiles, snakes are top predators and therefore a decline in their numbers may have serious consequences for the functioning of many ecosystems. Our results show that, of 17 snake populations (eight species) from the UK, France, Italy, Nigeria and Australia, 11 have declined sharply over the same relatively short period of time with five remaining stable and one showing signs of a marginal increase. Although the causes of these declines are currently unknown, we suspect that they are multi-faceted (such as habitat quality deterioration, prey availability), and with a common cause, e.g. global climate change, at their root.

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Hutchings, Jeffrey A., i Julia K. Baum. "Measuring marine fish biodiversity: temporal changes in abundance, life history and demography". Philosophical Transactions of the Royal Society B: Biological Sciences 360, nr 1454 (28.02.2005): 315–38. http://dx.doi.org/10.1098/rstb.2004.1586.

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Patterns in marine fish biodiversity can be assessed by quantifying temporal variation in rate of population change, abundance, life history and demography concomitant with long-term reductions in abundance. Based on data for 177 populations (62 species) from four north-temperate oceanic regions (Northeast Atlantic and Pacific, Northwest Atlantic, North mid-Atlantic), 81% of the populations in decline prior to 1992 experienced reductions in their rate of loss thereafter; species whose rate of population decline accelerated after 1992 were predominantly top predators such as Atlantic cod ( Gadus morhua ), sole ( Solea solea ) and pelagic sharks. Combining population data across regions and species, marine fish have declined 35% since 1978 and are currently less than 70% of recorded maxima; demersal species are generally at historic lows, pelagic species are generally stable or increasing in abundance. Declines by demersal species have been associated with substantive increases in pelagic species, a pattern consistent with the hypothesis that increases in the latter may be attributable to reduced predation mortality. There is a need to determine the consequences to population growth effected by the reductions in age (21%) and size (13%) at maturity and in mean age (5%) and size (18%) of spawners, concomitant with population decline. We conclude that reductions in the rate of population decline, in the absence of targets for population increase, will be insufficient to effect a recovery of marine fish biodiversity, and that great care must be exercised when interpreting multi-species patterns in abundance. Of fundamental importance is the need to explain the geographical, species-specific and habitat biases that pervade patterns of marine fish recovery and biodiversity.

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Armstrong, W. A., M. S. Teitelbaum i Jay M. Winter. "The Fear of Population Decline." Economic History Review 39, nr 4 (listopad 1986): 669. http://dx.doi.org/10.2307/2596505.

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Pohlman, Edward, Michael S. Teitelbaum i Jay M. Winter. "The Fear of Population Decline." Contemporary Sociology 16, nr 3 (maj 1987): 362. http://dx.doi.org/10.2307/2070306.

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Graham, David, i Michael H. Ralphs. "Population Decline of White Locoweed". Rangelands 34, nr 5 (październik 2012): 12–14. http://dx.doi.org/10.2111/rangelands-d-12-00023.1.

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Ahmad, Shahid, i Ghulam Nabi. "Pakistan’s markhor population in decline". Science 375, nr 6577 (14.01.2022): 153. http://dx.doi.org/10.1126/science.abn0745.

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Lynch, Katherine A., Michael S. Teitelbaum i Jay M. Winter. "The Fear of Population Decline". American Historical Review 92, nr 2 (kwiecień 1987): 382. http://dx.doi.org/10.2307/1866631.

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Grebenik, E. "The Fear of Population Decline". Population Studies 41, nr 2 (1.07.1987): 338–39. http://dx.doi.org/10.1080/0032472031000142936.

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Campos-Silva, João Vitor. "Giant fish bucks population decline". Nature 574, nr 7776 (1.10.2019): 36. http://dx.doi.org/10.1038/d41586-019-02926-5.

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Chu, C. Y. Cyrus. "Biodiversity decline and population externalities". Journal of Population Economics 21, nr 1 (21.10.2006): 173–81. http://dx.doi.org/10.1007/s00148-006-0103-x.

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Zinsmeister, Karl, Michael S. Teitelbaum i Jay M. Winter. "The Fear of Population Decline." Population and Development Review 12, nr 3 (wrzesień 1986): 589. http://dx.doi.org/10.2307/1973228.

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McDonald, John F. "Minority groups in the metropolitan Chicago housing market: 1970–2015". Urban Studies 55, nr 11 (31.10.2017): 2431–50. http://dx.doi.org/10.1177/0042098017732513.

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This paper examines the housing market of metropolitan Chicago from 1970 to 2015, with particular attention on the three largest minority groups – African Americans, Hispanics and Asians. The Hispanic and Asian populations of the metropolitan area have grown rapidly, while the African-American population has actually declined since 2000. Metro Chicago has a much larger Hispanic population than is typical for major northern metro areas in the USA. Suburban growth coupled with population decline in the central city has produced large minority populations in the suburbs along with sharp declines in the traditional African-American areas of the central city. African-American areas of concentrated poverty remain. Sizable mostly white population growth has occurred in and near the downtown area as most of the nearby public housing has been demolished.

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Arnott, S. E., S. S. E. Azan i A. J. Ross. "Calcium decline reduces population growth rates of zooplankton in field mesocosms". Canadian Journal of Zoology 95, nr 5 (maj 2017): 323–33. http://dx.doi.org/10.1139/cjz-2016-0105.

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Regional calcium (Ca) decline, a legacy of acid deposition and logging, is a potential threat to aquatic organisms. Lake surveys and laboratory studies indicate that Ca-rich daphniids are likely most susceptible, allowing for competitive release of other taxa with low Ca demand. Indeed, dramatic shifts in zooplankton community structure have been documented in lakes where Ca has declined, amid multiple other stressors. Given the perceived threat of this large-scale stressor, manipulative studies are needed to evaluate causal relationships between Ca decline and zooplankton community structure. We analysed per capita growth rates of zooplankton from three independent mesocosm experiments where we manipulated aqueous Ca concentrations to reflect current and future Ca concentrations. In two experiments where Ca concentration was reduced to 0.6 or 0.9 mg/L, we observed reduced growth rates for several taxa, including daphniids, bosminids, and copepods. No effect of Ca was detected in the experiment where Ca concentrations ranged from 1.2 to 2.5 mg/L, a gradient representing 68% of lakes in south-central Ontario. These results suggest that future Ca decline in soft-water Canadian Shield lakes may be accompanied by shifts in community structure and overall declines in zooplankton production.

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Wayne, A. F., M. A. Maxwell, C. G. Ward, C. V. Vellios, B. G. Ward, G. L. Liddelow, I. Wilson, J. C. Wayne i M. R. Williams. "Importance of getting the numbers right: quantifying the rapid and substantial decline of an abundant marsupial, Bettongia penicillata". Wildlife Research 40, nr 3 (2013): 169. http://dx.doi.org/10.1071/wr12115.

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Context A reliable measure of population size is fundamental to ecology and conservation but is often difficult to obtain. The woylie, Bettongia penicillata, provides an example where ‘getting the numbers right’ has important implications in verifying and quantifying the recent unexpected, rapid and substantial declines across much of its range. Initial estimates prompted a conservation-status upgrade for the species to Endangered by the Australian Government. The present paper constitutes the foundational paper addressing the first steps of a decline diagnosis framework intended to identify the causes of the recent declines. Aims To verify whether the declines in woylie trap-capture rates are representative of population change; better quantify the size of the largest woylie populations; and review what is understood about the ecology of the woylie and identify key knowledge gaps that may be relevant to identifying the causes of the recent declines. Methods Monitoring data from live-cage trapping (transects and grids), sandpads, woylie diggings and nest-density surveys and spotlighting were collated. Population measures derived from trapping data included capture rates, number of individuals, abundance estimates based on capture–mark–recapture modelling and density using spatially explicit capture–recapture models (SECR). Key results The declines in woylie trap-capture rates were verified as real population declines and corresponded closely with other measures of abundance derived from the same trapping data as well as with independent measures. A 95% decline occurred in the largest extant woylie populations (in the Upper Warren region, Western Australia) between 2002 and 2008. At a species level, woylies declined ~90% (1999–2006), from a peak of ~200 000 individuals in 1999. Conclusions An accurate formal conservation status is an important factor in promoting the conservation of a species. It is recommended that the woylie be considered for Critically Endangered status under the Australian EPBC Act. Implications Adequate and effective monitoring of species is critical to detecting and quantifying population changes in a timely manner. Having an accurate measure of population size can have a significant impact on the effectiveness of conservation and management efforts.

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Grujić, Nikola, i Milan Radivojević. "Population decline of Globodera rostochiensis in Western Serbia". Nematology 19, nr 2 (2017): 185–95. http://dx.doi.org/10.1163/15685411-00003039.

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Annual decline rates of potato cyst nematode (PCN) populations have been extensively studied. They vary considerably due to many factors, including potato cultivar, initial PCN density and climatic factors. Information is needed on PCN decline in potato fields in the specific conditions of Western Serbia, which is the centre for most of the local potato production, especially seed potato. We investigated the decline of Globodera rostochiensis over 1 or 2 years under the influence of PCN-resistant potato cv. Agria in the field and microplots. Decline was compared with fallow in Ponikve, near the original record of G. rostochiensis. Population decline in the field after cv. Agria was approximately 80%. In two parts of the field where potato cv. Agria was cropped once or twice with fallow before and after, the viable PCN population declined over 9 years to about 1% of initial values. In a third part of the field, left fallow for 9 years, 15% of the initial population was still viable, after an annual decline rate of 9.4%. The influence of volunteer potatoes on maintaining PCN populations was also examined. In the microplots, with a higher density of volunteers compared to the field, PCN decline under resistant potato cv. Agria was 70%. At crop harvest a new generation was recorded, suggesting its possible formation on susceptible volunteer potato. The full cysts represented 1% of all cysts examined and 13% of total second-stage juveniles found in the samples. The information will be useful for improvement of management procedures.

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Severud, William J., Sergey S. Berg, Connor A. Ernst, Glenn D. DelGiudice, Seth A. Moore, Steve K. Windels, Ron A. Moen, Edmund J. Isaac i Tiffany M. Wolf. "Statistical population reconstruction of moose (Alces alces) in northeastern Minnesota using integrated population models". PLOS ONE 17, nr 9 (27.09.2022): e0270615. http://dx.doi.org/10.1371/journal.pone.0270615.

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Given recent and abrupt declines in the abundance of moose (Alces alces) throughout parts of Minnesota and elsewhere in North America, accurately estimating statewide population trends and demographic parameters is a high priority for their continued management and conservation. Statistical population reconstruction using integrated population models provides a flexible framework for combining information from multiple studies to produce robust estimates of population abundance, recruitment, and survival. We used this framework to combine aerial survey data and survival data from telemetry studies to recreate trends and demographics of moose in northeastern Minnesota, USA, from 2005 to 2020. Statistical population reconstruction confirmed the sharp decline in abundance from an estimated 7,841 (90% CI = 6,702–8,933) in 2009 to 3,386 (90% CI = 2,681–4,243) animals in 2013, but also indicated that abundance has remained relatively stable since then, except for a slight decline to 3,163 (90% CI = 2,403–3,718) in 2020. Subsequent stochastic projection of the population from 2021 to 2030 suggests that this modest decline will continue for the next 10 years. Both annual adult survival and per-capita recruitment (number of calves that survived to 1 year per adult female alive during the previous year) decreased substantially in years 2005 and 2019, from 0.902 (SE = 0.043) to 0.689 (SE = 0.061) and from 0.386 (SE = 0.030) to 0.303 (SE = 0.051), respectively. Sensitivity analysis revealed that moose abundance was more sensitive to fluctuations in adult survival than recruitment; thus, we conclude that the steep decline in 2013 was driven primarily by decreasing adult survival. Our analysis demonstrates the potential utility of using statistical population reconstruction to monitor moose population trends and to identify population declines more quickly. Future studies should focus on providing better estimates of per-capita recruitment, using pregnancy rates and calf survival, which can then be incorporated into reconstruction models to help improve estimates of population change through time.

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Harrington, Graham N., i Stephen A. Murphy. "The distribution and conservation status of Carpentarian grasswrens (Amytornis dorotheae), with reference to prevailing fire patterns". Pacific Conservation Biology 21, nr 4 (2015): 291. http://dx.doi.org/10.1071/pc15021.

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The Carpentarian grasswren (Amytornis dorotheae) is a small, shy passerine patchily distributed through Triodia systems in the central and southern parts of Australia’s tropical savannas. Population decline has been reported in the Northern Territory, presumably due to mismanaged fire. The species is considered Endangered in the Northern Territory and Near Threatened in Queensland, but it is not listed Federally. Here, we present the results of over 3000 surveys conducted between 2008 and 2013. We show that Carpentarian grasswrens are divided into four populations, although the northernmost one (Borroloola) now appears to be extinct. The Area of Occupancy for the southernmost population appears to have declined by 28%, while only small numbers of isolated birds now occur at the two intervening populations. Our data suggest that the four populations appear to be at different stages on an extinction pathway, from population decline, to fragmentation and isolation, to extinction, and this seems to be related to worsening fire patterns as one moves northwards. We suggest that the Carpentarian grasswren be listed as Vulnerable at the State and Federal level, and that urgent investment in long-term regional fire management using prescribed burning is required to reverse the declines in the extant populations. For the presumed extinct Borroloola population, restoration will probably need to involve translocation coupled with effective fire management.

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Cappa, Veronica, Monica Pierangela Cerioli, Alessandra Scaburri, Marco Tironi, Marco Farioli, Claudia Nassuato i Silvia Bellini. "Analysis of Bee Population Decline in Lombardy during the Period 2014–2016 and Identification of High-Risk Areas". Pathogens 10, nr 8 (9.08.2021): 1004. http://dx.doi.org/10.3390/pathogens10081004.

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The first events of bee decline in Italy were reported during 1999. Since then, population decline has frequently been reported in Lombardy. In this study, the association between bee decline and the type of land surrounding the apiary was evaluated. A risk map was developed to identify areas with the highest risk of decline. Apiaries in Lombardy were selected from the national beekeeping database (BDA). The study period was from 2014 to 2016. Apiaries were deemed “declined” if they reported at least one event of decline or tested positive for plant protection products; apiaries were “not declined” if they did not report any events of bee decline during the study period. Out of 14,188 apiaries extracted from the BDA, 80 were considered declined. The probability of an apiary being declined increases by 10% in orchards and by 2% in arable land for each additional km2 of land occupied by these crops. The study showed an association between bee decline and the type of territory surrounding the apiaries, and the areas at the greatest risk of decline in Lombardy were identified. This information can be used by Veterinary Services as a predictive parameter for planning prevention and control activities.

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HAARTSEN, TIALDA, i VIKTOR VENHORST. "PLANNING FOR DECLINE: ANTICIPATING ON POPULATION DECLINE IN THE NETHERLANDS". Tijdschrift voor economische en sociale geografie 101, nr 2 (kwiecień 2010): 218–27. http://dx.doi.org/10.1111/j.1467-9663.2010.00597.x.

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Laundré, J. W., L. Hernández i S. G. Clark. "Impact of puma predation on the decline and recovery of a mule deer population in southeastern Idaho". Canadian Journal of Zoology 84, nr 11 (listopad 2006): 1555–65. http://dx.doi.org/10.1139/z06-150.

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We modeled the impact of puma ( Puma concolor (L., 1771)) predation on the decline and recovery of mule deer ( Odocoileus hemionus (Rafinesque, 1817)) in southern Idaho based on estimates of puma numbers, predation rates of pumas, and reproductive variables of deer. Deer populations peaked in 1992–1993, then declined more than 55% and remained low for the next 11 years. Puma numbers peaked 4–6 years after deer populations peaked but then declined to original levels. Estimated puma predation on the deer population before and after the decline was 2.2%–3.3% and 3.1%–5.8%, respectively. At high puma densities (>3 pumas/100 km2), predation by pumas delayed deer recovery by 2–3 years. Percent winter mortality of fawns (r2 = 0.62, P < 0.001) and adult female deer (r2 = 0.68, P < 0.001) correlated positively with December–January snowfall. Incorporation of winter snowfall amounts in the model produced a pattern of deer population change matching estimated changes based on field survey data. We conclude that pumas probably were a minor factor in the decline of the deer population in our area and did not suppress deer recovery. We propose that winter snowfall was the primary ultimate and proximate factor in the deer decline and suppression of their recovery.

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Beaumont, Mark A. "Estimation of Population Growth or Decline in Genetically Monitored Populations". Genetics 164, nr 3 (1.07.2003): 1139–60. http://dx.doi.org/10.1093/genetics/164.3.1139.

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AbstractThis article introduces a new general method for genealogical inference that samples independent genealogical histories using importance sampling (IS) and then samples other parameters with Markov chain Monte Carlo (MCMC). It is then possible to more easily utilize the advantages of importance sampling in a fully Bayesian framework. The method is applied to the problem of estimating recent changes in effective population size from temporally spaced gene frequency data. The method gives the posterior distribution of effective population size at the time of the oldest sample and at the time of the most recent sample, assuming a model of exponential growth or decline during the interval. The effect of changes in number of alleles, number of loci, and sample size on the accuracy of the method is described using test simulations, and it is concluded that these have an approximately equivalent effect. The method is used on three example data sets and problems in interpreting the posterior densities are highlighted and discussed.

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Wilson, Barbara A., Mandy Lock i Mark J. Garkaklis. "Long-term fluctuations in distribution and populations of a threatened rodent (Pseudomys novaehollandiae) in coastal woodlands of the Otway Ranges, Victoria: a regional decline or extinction?" Australian Mammalogy 40, nr 2 (2018): 281. http://dx.doi.org/10.1071/am17036.

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Since European settlement Australian native rodents have experienced dramatic extinctions and declines. We investigated long-term population and distribution changes during 1981–2003, and known or potential causal factors of decline in the vulnerable New Holland mouse (Pseudomys novaehollandiae). We found that populations (n = 8) were extant for 1–6 years and were predominantly small, localised and extinction prone. High-density populations occurred after above-average rainfall but declined precipitously during drought. Wildfire resulted in the extirpation of some populations, while others survived in unburnt refugia. We propose that post-fire vegetation (3–7 years) contemporaneous with above-average rainfall delivered productive habitat resulting in both a population irruption, and recovery after wildfire. Population declines occurred in drought periods. Recent trapping at 42 sites (2013–17) failed to record any New Holland mice. The species has not been recorded since 2003. Recovery is unlikely without intensive management, focussed on remnant or reintroduced populations, including protection from habitat fragmentation and inappropriate fire regimes. Prevention of extinction of the species throughout its southern range will require similar management strategies.

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Uzqueda, Adriana, Scott Burnett, Lorenzo V. Bertola i Conrad J. Hoskin. "Quantifying range decline and remaining populations of the large marsupial carnivore of Australia’s tropical rainforest". Journal of Mammalogy 101, nr 4 (17.08.2020): 1021–34. http://dx.doi.org/10.1093/jmammal/gyaa077.

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Abstract Large predators are particularly susceptible to population declines due to large area requirements, low population density, and conflict with humans. Their low density and secretive habits also make it difficult to know the spatial extent, size, and connectivity of populations; declines hence can go unnoticed. Here, we quantified decline in a large marsupial carnivore, the spotted-tailed quoll (Dasyurus maculatus gracilis), endemic to the Wet Tropics rainforest of northeast Australia. We compiled a large database of occurrence records and used species distributional modeling to estimate the distribution in four time periods (Pre-1956, 1956–1975, 1976–1995, 1996–2016) using climate layers and three human-use variables. The most supported variables in the distribution models were climatic, with highly suitable quoll habitat having relatively high precipitation, low temperatures, and a narrow annual range in temperature. Land-use type and road density also influenced quoll distribution in some time periods. The modeling revealed a significant decline in the distribution of D. m. gracilis over the last century, with contraction away from peripheral areas and from large areas of the Atherton Tablelands in the center of the distribution. Tests of the change in patch availability for populations of 20, 50, and 100 individuals revealed a substantial (17–32%) decline in available habitat for all population sizes, with a particular decline (31–40%) in core habitat (i.e., excluding edges). Six remaining populations were defined. Extrapolating capture–recapture density estimates derived from two populations in 2017 suggests these populations are small and range from about 10 to 160 individuals. Our total population estimate sums to 424 individuals, but we outline why this estimate is positively skewed and that the actual population size may be < 300 individuals. Continued decline and apparent absence in areas of highly suitable habitat suggests some threats are not being captured in our models. From our results, we provide management and research recommendations for this enigmatic predator.

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31

Hone, Jim, the late Graeme Caughley i David Grice. "An experimental study of declining populations". Wildlife Research 32, nr 6 (2005): 481. http://dx.doi.org/10.1071/wr04092.

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Wildlife population declines have been attributed to predation, habitat change, and other agents of decline. An experimental study applied predation (at three levels) and habitat (at two levels) treatments over two years and measured the patterns of decline of populations of a medium-sized mammal (European rabbits). A model of population dynamics and effects of the treatments predicted negative effects of both treatments and an interaction of the treatments. All populations declined during the study including the experimental controls. During the first seven months (first phase of the study) the rate of decline, as estimated by the observed monthly instantaneous rate of increase (r), was more negative (P < 0.05) with increasing predation levels but there was no effect (P > 0.05) of habitat manipulation on r. There were no significant effects of treatments on rabbit abundance, or density, during the first phase of the study. During the second phase of the study, of 12 months’ duration, there were no significant (P > 0.05) effects of treatments on rabbit abundance, density, or r. There were no significant (P > 0.05) interactions of treatments on any response variable during either phase of the study. The interaction predicted by the theoretical model was not supported. Estimated abundance at the end of the study was not related (P > 0.05) to initial abundance (correlation = 0.023). The implications of the results are that such experimental studies can be used to evaluate theoretical models, though such studies may require a larger number of treatment replicates, and treatments at more extreme levels, to more clearly detect the effects of agents of population decline and their interactions.

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Gurven, Michael, Thomas S. Kraft, Sarah Alami, Juan Copajira Adrian, Edhitt Cortez Linares, Daniel Cummings, Daniel Eid Rodriguez i in. "Rapidly declining body temperature in a tropical human population". Science Advances 6, nr 44 (październik 2020): eabc6599. http://dx.doi.org/10.1126/sciadv.abc6599.

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Normal human body temperature (BT) has long been considered to be 37.0°C. Yet, BTs have declined over the past two centuries in the United States, coinciding with reductions in infection and increasing life expectancy. The generality of and reasons behind this phenomenon have not yet been well studied. Here, we show that Bolivian forager-farmers (n = 17,958 observations of 5481 adults age 15+ years) inhabiting a pathogen-rich environment exhibited higher BT when first examined in the early 21st century (~37.0°C). BT subsequently declined by ~0.05°C/year over 16 years of socioeconomic and epidemiological change to ~36.5°C by 2018. As predicted, infections and other lifestyle factors explain variation in BT, but these factors do not account for the temporal declines. Changes in physical activity, body composition, antibiotic usage, and thermal environment are potential causes of the temporal decline.

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Ildarkhanova, Chulpan, Alisa Ibragimova i Artur Abdulzyanov. "Dynamics of the natural movement of the population as a threat to the demographic security of Russia". Population 25, nr 3 (29.09.2022): 4–17. http://dx.doi.org/10.19181/population.2022.25.3.1.

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This article examines the retrospective dynamics of the natural movement of the population of the Russian Federation from the perspective of achieving demographic security of the country. The purpose of the work is to analyze the indicator of natural population growth/decline through economic demography and social demography to identify the impact of socio-economic conditions on demographic processes and the impact of demographic factors of changes in the natural movement of the population on socio-economic dynamics. To achieve this goal, Family and Demography Center of the Tatarstan Academy of Sciences, with the direct participation of the authors, conducted a monitoring study of demographic processes (natural population growth/ decline, fertility and mortality) for the period from 2000 to 2020 within the framework of the preparation of the Demographic Report-2021 "Retrospectives and prospects of reproduction of the population of the Republic of Tatarstan (2000-2020)", which made it possible to analyze the dynamics of these demographic processes. The Russian Federation is in a demographic crisis, which is characterized by depopulation, when mortality exceeds fertility, which is especially aggravated due to the spread of the COV1D-19. Changes in the natural movement of the population are largely determined by changes in the sex and age structure of the population: a decrease in the number of women of reproductive age, increased mortality of men of working age, aging of the population. 1n the course of work on the article, the results of the sociological study "Demographic Well-Being of Russia", conducted in 2020 with the participation of the authors of the article, as well as regression and correlation analysis were used to identify the relationship between variables. The results obtained indicate the relationship between natural population decline and economic processes. The negative consequences are connected with a reduction in the labor force, aging of the population, deterioration of public health, etc. The results of the study are of practical value for the development of an effective demographic policy of the Russia.

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Radkar, Anjali. "Indian Fertility Transition". Journal of Health Management 22, nr 3 (wrzesień 2020): 413–23. http://dx.doi.org/10.1177/0972063420937925.

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Fighting to curb the population growth, India’s reduction in fertility rate (58%) in 35 years is evident; total fertility rate (TFR) declined from 5.2 to 2.2 meaning three children less. According to the National Family Health Survey (NFHS-4), 2015–2016, TFR has dropped to 2.18 from 3.39 in 1992 (NFHS-1). Proximate determinants indicate that over a period, index of marriage and contraception contribute lesser towards fertility, and postpartum amenorrhoea shows marginal variation. When total fecundity remains constant, share of abortion does not remain one but contribute towards fertility reduction. Benefits of fertility decline include lowering population growth and its positive effects on overall development. As fertility declines, maternal mortality declines; maternal mortality ratio (MRR) declined by 67 per cent in past 13 years. Sharp decline in fertility gives rise to demographic dividend. India is passing through it. Fertility drop is not without consequences. Fertility decline makes pregnancies precious; giving rise to upswing to C-section deliveries and hysterectomy even for a minor cause or is it a response to cancer threat? Preference for sons is universal here. With fertility reduction, it surfaces with unruly consequences of missing girls. Drop in fertility has changed the shape of the population pyramid. Share of elderly is reaching 10 per cent, of which share of women and more so share of oldest women is more. In the absence of social security and low rates of workforce participation, women are getting more dependent on the required care, increasing their vulnerability. Fertility reduction has achieved with moderate level of development. Now the right response to effects of fertility decline is the biggest social challenge.

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Miyamoto, Taro. "Population Decline and Welfare-employment Regime:". Iryo To Shakai 27, nr 1 (2017): 99–109. http://dx.doi.org/10.4091/iken.27.99.

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Mainali, Kumar P. "Sharp Decline in Nepal's Rhino Population". Frontiers in Ecology and the Environment 3, nr 5 (czerwiec 2005): 239. http://dx.doi.org/10.2307/3868480.

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Azevedo-Ramos, Claudia. "Canadian Studies of Amphibian Population Decline". Ecology 79, nr 7 (październik 1998): 2573–74. http://dx.doi.org/10.1890/0012-9658(1998)079[2573:csoapd]2.0.co;2.

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Bosch, X. "Spain faces massive decline in population". BMJ 320, nr 7239 (1.04.2000): 891. http://dx.doi.org/10.1136/bmj.320.7239.891.

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Thiollay, Jean-Marc. "Raptor population decline in West Africa". Ostrich 78, nr 2 (czerwiec 2007): 405–13. http://dx.doi.org/10.2989/ostrich.2007.78.2.46.126.

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Juan-Jordá, M. J., I. Mosqueira, J. Freire i N. K. Dulvy. "Population declines of tuna and relatives depend on their speed of life". Proceedings of the Royal Society B: Biological Sciences 282, nr 1811 (22.07.2015): 20150322. http://dx.doi.org/10.1098/rspb.2015.0322.

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Larger-bodied species in a wide range of taxonomic groups including mammals, fishes and birds tend to decline more steeply and are at greater risk of extinction. Yet, the diversity in life histories is governed not only by body size, but also by time-related traits. A key question is whether this size-dependency of vulnerability also holds, not just locally, but globally across a wider range of environments. We test the relative importance of size- and time-related life-history traits and fishing mortality in determining population declines and current exploitation status in tunas and their relatives. We use high-quality datasets of half a century of population trajectories combined with population-level fishing mortalities and life-history traits. Time-related traits (e.g. growth rate), rather than size-related traits (e.g. maximum size), better explain the extent and rate of declines and current exploitation status across tuna assemblages, after controlling for fishing mortality. Consequently, there is strong geographical patterning in population declines, such that populations with slower life histories (found at higher cooler latitudes) have declined most and more steeply and have a higher probability of being overfished than populations with faster life histories (found at tropical latitudes). Hence, the strong, temperature-driven, latitudinal gradients in life-history traits may underlie the global patterning of population declines, fisheries collapses and local extinctions.

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Brown, David E., Andrew T. Smith, Jennifer K. Frey i Brittany R. Schweiger. "A Review of the Ongoing Decline of the White-Tailed Jackrabbit". Journal of Fish and Wildlife Management 11, nr 1 (25.11.2019): 341–52. http://dx.doi.org/10.3996/042019-jfwm-026.

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Abstract The distribution and abundance of the white-tailed jackrabbit Lepus townsendii have declined significantly since 1950, continuing a trend that began in some regions of its range in the late 1800s. We reviewed museum records and the literature to evaluate the status of the white-tailed jackrabbit in each state and province in its historical range and evaluated possible reasons for its decline. Our evaluation revealed its extirpation or decline throughout much of its range, but its legal or conservation status does generally not reflect this precarious status. We note its extirpation in Missouri, Kansas and Oklahoma, and potential extirpation in British Columbia, Oregon, Illinois, and Wisconsin. We classified the white-tailed jackrabbit to be broadly extirpated in Iowa, Minnesota, Washington, Nebraska and California, and declining with local extirpations in Wyoming, Nevada, Utah, Colorado, New Mexico, and South Dakota. We consider it to be a relict in Ontario, and possibly declining in Alberta, Saskatchewan, North Dakota, Idaho, and Montana. We consider only Manitoba to have a possibly stable population. Determining the reasons for the species' reduced distribution is difficult, as the decline appears to be due to multiple factors, none of which provide a universal explanation. We dismissed road kills, recreational hunting, disease and parasites, and competition with black-tailed jackrabbits Lepus californicus as causes of the widespread population declines and extirpations. We concluded that habitat alterations and climate change are overriding factors, and that past depredation measures and increased predator populations have likely contributed to the decline. These hypotheses require further testing. We recommend more research on the distribution, abundance, ecology, and population dynamics of white-tailed jackrabbits, and management that includes a frank appraisal of the species' status, the potential for grassland restoration, and programs to reintroduce populations into prairie preserves and restored grasslands.

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Clark, TW, JP Gibbs i PW Goldstraw. "Some demographics of the extirpation from the wild of eastern barred bandicoots (Perameles gunni) in 1988-91, near Hamilton, Victoria, Australia". Wildlife Research 22, nr 3 (1995): 289. http://dx.doi.org/10.1071/wr9950289.

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The threatened, free-ranging mainland poplation, of the eastern barred bandicoot in the Hamilton area of Victoria declined to near extinction in late 1992. Demographic changes associated with the decline were monitored from 1988 to 1992. About 200 different animals were captured in 1988,49 in 1989, 16 in 1990, 3 in 1991 and 3 in 1992; capture rates (number of bandicoots captured per trap-night) displayed a similar pattern: 0.5 in 1988,O.l in 1989,0.05 in 1990,0.05 in 1991 and 0.02 in 1992. Observed declines lay within the 5% confidence intervals predicted by a demographic model for a population subjected to a removal rate of 14 animals per three months (the number removed for captive breeding by managers). Removal of bandicoots to stock a captive population hastened the demise of the wild population by about seven years; however, even in the absence of removals of animals, extinction was impending within 5-10 years. Sex ratios were male-biased in all years except 1988; the bias may have resulted from stochastic events. Average litter sizes did not differ between the 1988 population and subsequent populations, except for the 1991 population, in which a predominance of non-reproductive females contributed to a strong decline in average litter size. These demographic trends illustrate how the synergy between stochastic and deterministic forces can rapidly drive a small population to extinction.

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Rowe, Sherrylynn, Jeffrey A. Hutchings, Dorte Bekkevold i Ana Rakitin. "Depensation, probability of fertilization, and the mating system of Atlantic cod (Gadus morhua L.)". ICES Journal of Marine Science 61, nr 7 (1.01.2004): 1144–50. http://dx.doi.org/10.1016/j.icesjms.2004.07.007.

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Abstract Atlantic cod (Gadus morhua L.) have been severely overexploited and are currently at historic population lows, having declined 90% in the North Sea and 99% off northeast Newfoundland in recent decades. Slow rates of recovery and continuing declines may be attributable to depensation, defined as a reduction in per capita growth rate concomitant with reduced population size. Several potential causes of depensation relate to low mating success and consequent reduced production of offspring. We explore the empirical basis of one of these in Atlantic cod using egg fertilization and male abundance data obtained from 21 experimental populations generated by three independent research programmes. We find support for the hypotheses that (a) fertilization rate declines with abundance and (b) variance in fertilization rate increases as population size declines. The former identifies one potential mechanism underlying depensation in Atlantic cod. The latter has negative genetic consequences for effective population size (Ne), resulting in a decline in the ratio of Ne to census population size (Ne/Nc) with declining abundance. Our results may have general implications for the conservation biology of broadcast-spawning marine fish, particularly those with mating systems similar to that of Atlantic cod.

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Dietzel, Andreas, Michael Bode, Sean R. Connolly i Terry P. Hughes. "Long-term shifts in the colony size structure of coral populations along the Great Barrier Reef". Proceedings of the Royal Society B: Biological Sciences 287, nr 1936 (14.10.2020): 20201432. http://dx.doi.org/10.1098/rspb.2020.1432.

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The age or size structure of a population has a marked influence on its demography and reproductive capacity. While declines in coral cover are well documented, concomitant shifts in the size-frequency distribution of coral colonies are rarely measured at large spatial scales. Here, we document major shifts in the colony size structure of coral populations along the 2300 km length of the Great Barrier Reef relative to historical baselines (1995/1996). Coral colony abundances on reef crests and slopes have declined sharply across all colony size classes and in all coral taxa compared to historical baselines. Declines were particularly pronounced in the northern and central regions of the Great Barrier Reef, following mass coral bleaching in 2016 and 2017. The relative abundances of large colonies remained relatively stable, but this apparent stability masks steep declines in absolute abundance. The potential for recovery of older fecund corals is uncertain given the increasing frequency and intensity of disturbance events. The systematic decline in smaller colonies across regions, habitats and taxa, suggests that a decline in recruitment has further eroded the recovery potential and resilience of coral populations.

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Hollings, Tracey, Hamish McCallum, Kaely Kreger, Nick Mooney i Menna Jones. "Relaxation of risk-sensitive behaviour of prey following disease-induced decline of an apex predator, the Tasmanian devil". Proceedings of the Royal Society B: Biological Sciences 282, nr 1810 (7.07.2015): 20150124. http://dx.doi.org/10.1098/rspb.2015.0124.

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Apex predators structure ecosystems through lethal and non-lethal interactions with prey, and their global decline is causing loss of ecological function. Behavioural changes of prey are some of the most rapid responses to predator decline and may act as an early indicator of cascading effects. The Tasmanian devil ( Sarcophilus harrisii ), an apex predator, is undergoing progressive and extensive population decline, of more than 90% in long-diseased areas, caused by a novel disease. Time since local disease outbreak correlates with devil population declines and thus predation risk. We used hair traps and giving-up densities (GUDs) in food patches to test whether a major prey species of devils, the arboreal common brushtail possum ( Trichosurus vulpecula ), is responsive to the changing risk of predation when they forage on the ground. Possums spend more time on the ground, discover food patches faster and forage more to a lower GUD with increasing years since disease outbreak and greater devil population decline. Loss of top–down effects of devils with respect to predation risk was evident at 90% devil population decline, with possum behaviour indistinguishable from a devil-free island. Alternative predators may help to maintain risk-sensitive anti-predator behaviours in possums while devil populations remain low.

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Hansen, Michael M., Einar E. Nielsen i Karen-Lise D. Mensberg. "Underwater but not out of sight: genetic monitoring of effective population size in the endangered North Sea houting (Coregonus oxyrhynchus)". Canadian Journal of Fisheries and Aquatic Sciences 63, nr 4 (1.04.2006): 780–87. http://dx.doi.org/10.1139/f05-260.

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We analysed 12 microsatellite DNA loci in temporal samples (1980, 1994, and 2002) from the only remaining indigenous population of the North Sea houting (Coregonus oxyrhynchus) in the Vidaa River, Denmark. Using a novel temporal method, we estimated effective population size (Ne) to be 577.4 (90% highest posterior density limits 297.23719.8). The same method was used to estimate Ne at the beginning and end of the sampled time interval, and the results were indicative of a relatively stable population. In contrast, tests for recent bottlenecks suggested population declines in the 1980 and 1994 samples, possibly reflecting declines prior to 1980 in the total North Sea houting population. To evaluate the usefulness of the two methods for routine genetic monitoring, we simulated population declines corresponding to reproduction by only 20 or 50 parents in 2002. For both simulated samples, the temporal method provided evidence for a population decline, whereas the test for bottlenecks did not suggest population decline. We conclude that the North Sea houting in the Vidaa River is not immediately threatened by inbreeding or loss of evolutionary potential, and the applied temporal method appears very useful for genetic monitoring of effective population size in endangered, isolated fish populations.

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Thogmartin, Wayne E., Ruscena Wiederholt, Karen Oberhauser, Ryan G. Drum, Jay E. Diffendorfer, Sonia Altizer, Orley R. Taylor i in. "Monarch butterfly population decline in North America: identifying the threatening processes". Royal Society Open Science 4, nr 9 (wrzesień 2017): 170760. http://dx.doi.org/10.1098/rsos.170760.

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The monarch butterfly ( Danaus plexippus ) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.

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Beaumont, Mark A. "Detecting Population Expansion and Decline Using Microsatellites". Genetics 153, nr 4 (1.12.1999): 2013–29. http://dx.doi.org/10.1093/genetics/153.4.2013.

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Abstract This article considers a demographic model where a population varies in size either linearly or exponentially. The genealogical history of microsatellite data sampled from this population can be described using coalescent theory. A method is presented whereby the posterior probability distribution of the genealogical and demographic parameters can be estimated using Markov chain Monte Carlo simulations. The likelihood surface for the demographic parameters is complicated and its general features are described. The method is then applied to published microsatellite data from two populations. Data from the northern hairy-nosed wombat show strong evidence of decline. Data from European humans show weak evidence of expansion.

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Kwon, Ja Kyung. "An Empirical Study for Implications to Respond the Crisis of Local Population Decline in South Korea". Crisis and Emergency Management: Theory and Praxis 12, nr 6 (30.06.2022): 13–22. http://dx.doi.org/10.14251/jscm.2022.6.13.

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In the non-Capital area of South Korea, it was found that the cause of the population decline was not solely due to the recent low birth rate. The severe population decline in the non-Capital area is due to the migration of the population to the Capital area. Therefore, this study looked at what regional development factors affect the local population increase. As a result of the regression analysis, the factors affecting population decline were the old housing rate, % of population in library service area, ratio of single-person households over 65, and water supply rate. As factors affecting population growth, green rate, number of residents in charge per 119 safety center, ratio of the school-age population within the elementary school service area, and urban park area per 1,000 people were derived. Based on the results of the empirical analysis, in order to respond to the crisis of local population decline, policies were proposed to remove the factors of population decrease and to activate the factors of population increase in non-Capital areas.

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Valenzuela-Sánchez, Andrés, Benedikt R. Schmidt, David E. Uribe-Rivera, Francisco Costas, Andrew A. Cunningham i Claudio Soto-Azat. "Cryptic disease-induced mortality may cause host extinction in an apparently stable host–parasite system". Proceedings of the Royal Society B: Biological Sciences 284, nr 1863 (27.09.2017): 20171176. http://dx.doi.org/10.1098/rspb.2017.1176.

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The decline of wildlife populations due to emerging infectious disease often shows a common pattern: the parasite invades a naive host population, producing epidemic disease and a population decline, sometimes with extirpation. Some susceptible host populations can survive the epidemic phase and persist with endemic parasitic infection. Understanding host–parasite dynamics leading to persistence of the system is imperative to adequately inform conservation practice. Here we combine field data, statistical and mathematical modelling to explore the dynamics of the apparently stable Rhinoderma darwinii – Batrachochytrium dendrobatidis (Bd) system. Our results indicate that Bd-induced population extirpation may occur even in the absence of epidemics and where parasite prevalence is relatively low. These empirical findings are consistent with previous theoretical predictions showing that highly pathogenic parasites are able to regulate host populations even at extremely low prevalence, highlighting that disease threats should be investigated as a cause of population declines even in the absence of an overt increase in mortality.

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