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.

Demographic analysis of a rare columnar cactus (Neobuxbaumia macrocephala) in the Tehuacan Valley, Mexico

2002 ◽  
Vol 103 (3) ◽  
pp. 349-359 ◽  
Author(s):  
Ligia Esparza-Olguı́n ◽  
Teresa Valverde ◽  
Elena Vilchis-Anaya
Keyword(s):  
Demographic Analysis ◽  
Tehuacán Valley ◽  
Columnar Cactus ◽  
Tehuacan Valley

Population dynamics of northern white-tailed deer during mild winters: evidence of regulation by food competition

2000 ◽  
Vol 78 (5) ◽  
pp. 764-776 ◽  
Author(s):  
André Dumont ◽  
Michel Crête ◽  
Jean-Pierre Ouellet ◽  
Jean Huot ◽  
Jean Lamoureux
Keyword(s):  
Population Dynamics ◽  
Survival Rates ◽  
Food Competition ◽  
Finite Rate ◽  
Mortality Pattern ◽  
Rate Of Increase ◽  
Wintering Area ◽  
Probability Of Death ◽  
Low Levels ◽  
Two Populations

We studied white-tailed deer (Odocoileus virginianus borealis) at the northeastern limit of their range after their density had decreased as a result of harsh winters aggravated by coyote predation. We compared two populations wintering in adjacent areas. In the Lac Témiscouata wintering area (LTWA), deer and browse density averaged 10 animals/km2 and 127 000 deciduous twigs/ha compared with 20 deer/km2 and 68 000 twigs/ha, respectively, at the Pohénégamook wintering area (PWA). For 75 radio-collared deer, the probability of death was highest during the short spring migration and remained elevated in winter, whereas fewer deaths occurred in summer and none during autumn migration. PWA deer had a higher mortality rate than did LTWA animals and died mostly in winter, from predation, starvation, and collision equally. Based on observed survival rates, we estimated that the finite rate of increase averaged [Formula: see text]1.25 and [Formula: see text]1.00 for LTWA and PWA populations, respectively. At PWA, we examined 129 carcasses to determine the mortality pattern of deer. Among adults, we did not detect significant differences related to sex. Starvation and predation affected more fawns and old deer than prime animals, whereas collision appeared to be nonselective. Most cases of starvation occurred after the beginning of March, when body reserves dropped to low levels. We conclude that competition for winter forage regulated PWA deer during the study.

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.

scholarly journals Demographic effects of interacting species: exploring stable coexistence under increased climatic variability in a semiarid shrub community

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana I. García-Cervigón ◽  
Pedro F. Quintana-Ascencio ◽  
Adrián Escudero ◽  
Merari E. Ferrer-Cervantes ◽  
Ana M. Sánchez ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Species Coexistence ◽  
Climatic Factors ◽  
Demographic Data ◽  
Climatic Variability ◽  
Biotic Interactions ◽  
Vital Rates ◽  
Climatic Fluctuations ◽  
Demographic Models ◽  
Shrub Community

AbstractPopulation persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.

scholarly journals New AMS Radiocarbon Ages from the Preceramic Levels of Coxcatlan Cave, Puebla, Mexico: A Pleistocene Occupation of the Tehuacan Valley?

2021 ◽  
pp. 1-15
Author(s):  
Andrew D. Somerville ◽  
Isabel Casar ◽  
Joaquín Arroyo-Cabrales
Keyword(s):  
Mass Spectrometry ◽  
Last Glacial Maximum ◽  
Food Production ◽  
Tehuacán Valley ◽  
Rock Shelter ◽  
Last Glacial ◽  
Tehuacan Valley ◽  
Peopling Of The Americas ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Archaeological studies at Coxcatlan Cave in the Tehuacan Valley of southern Puebla, Mexico, have been instrumental to the development of the chronology for the region and for our understanding of the origins of food production in the Americas. This article refines the Preceramic chronology of the Tehuacan Valley by presenting 14 new accelerated mass spectrometry (AMS) radiocarbon ages from faunal bone samples uncovered from early depositional levels of the rock shelter. Although bones associated with the El Riego (9893–7838 cal BP), Coxcatlan (7838–6375 cal BP), and Abejas (6375–4545 cal BP) phase zones of the cave yielded ages similar to those of the previously proposed chronology for the region, bones from the Ajuereado phase zones at the base of the cave yielded surprisingly old ages that range from 33,448 to 28,279 cal BP, a time prior to the Last Glacial Maximum. Because these early ages are many thousands of years older than current models estimate for the peopling of the Americas, they require reassessments of the artifacts and ecofacts excavated from these early zones.

scholarly journals The geographic scaling of biotic interactions

2013 ◽  
Author(s):  
Miguel B Araújo ◽  
Alejandro Rozenfeld
Keyword(s):  
Biotic Interactions ◽  
Species Distributions ◽  
Scale Dependence ◽  
Positive Interactions ◽  
Ample Evidence ◽  
Species Ranges ◽  
Central Tenet ◽  
Resource Interactions ◽  
Occurrence Patterns ◽  
Consumer Resource

A central tenet of ecology and biogeography is that the broad outlines of species ranges are determined by climate, whereas the effects of biotic interactions are manifested at local scales. While the first proposition is supported by ample evidence, the second is still a matter of controversy. To address this question, we develop a mathematical model that predicts the spatial overlap, i.e., co-occurrence, between pairs of species subject to all possible types of interactions. We then identify the scale in which predicted range overlaps are lost. We found that co-occurrence arising from positive interactions, such as mutualism (+/+) and commensalism (+/0), are manifested across scales of resolution. Negative interactions, such as competition (-/-) and amensalism (-/0), generate checkerboard-type co-occurrence patterns that are discernible at finer resolutions. Scale dependence in consumer-resource interactions (+/-) depends on the strength of positive dependencies between species. Our results challenge the widely held view that climate alone is sufficient to characterize species distributions at broad scales, but also demonstrate that the spatial signature of competition is unlikely to be discernible beyond local and regional scales.

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