Deletion of Rare Species Does Not Change the Conclusion That on Bahamian Islands Arthropods Have Greater Temporal Variability in Population Size Than Vertebrates

Oikos ◽  
1990 ◽  
Vol 58 (3) ◽  
pp. 385 ◽  
Author(s):  
Thomas W. Schoener
Keyword(s):  
Population Size ◽  
Rare Species ◽  
Temporal Variability

Conservation of Cape BArren Geese, Cereopsis novaehollandiae, in Tasmania

1981 ◽  
Vol 8 (1) ◽  
pp. 147 ◽  
Author(s):  
IH Eberhard ◽  
RJ Pearse
Keyword(s):  
Population Size ◽  
Rare Species ◽  
18Th Century ◽  
Population Monitoring ◽  
Management Program ◽  
Public Understanding ◽  
Public Concern ◽  
Improved Pasture ◽  
Local Farmers

'Cape Barren geese are restricted to the coastline of southern Australia; the Furneaux Group of islands, at the eastern end of Bass Strait, is one of two principal population centres. Population size has fluctuated since Europeans first settled in the Group at the end of the 18th century, as a result of variable predation on birds and eggs and of changes to habitat. Population monitoring began in 1957; numbers of geese appear to have at least doubled up to 1973. During this period large flocks of geese have grazed paddocks of improved pasture on Flinders I., the largest island of the Group, and this had led to outcry from local farmers. Because these geese are widely considered to be a rare species, shooting has prompted significant public concern. This paper describes the development and implementation of a management program to conserve Cape Barren geese in the Furneaux Group, while minimizing real hardships experienced by farmers and improving public understanding of the problem.

scholarly journals Comparing Genetic Diversity in Three Threatened Oaks

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 561
Author(s):  
Emma Suzuki Spence ◽  
Jeremie B. Fant ◽  
Oliver Gailing ◽  
M. Patrick Griffith ◽  
Kayri Havens ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Rare Species ◽  
Genetic Erosion ◽  
Geographic Range ◽  
Range Size ◽  
Ex Situ ◽  
Botanic Gardens ◽  
Geographic Range Size

Genetic diversity is a critical resource for species’ survival during times of environmental change. Conserving and sustainably managing genetic diversity requires understanding the distribution and amount of genetic diversity (in situ and ex situ) across multiple species. This paper focuses on three emblematic and IUCN Red List threatened oaks (Quercus, Fagaceae), a highly speciose tree genus that contains numerous rare species and poses challenges for ex situ conservation. We compare the genetic diversity of three rare oak species—Quercus georgiana, Q. oglethorpensis, and Q. boyntonii—to common oaks; investigate the correlation of range size, population size, and the abiotic environment with genetic diversity within and among populations in situ; and test how well genetic diversity preserved in botanic gardens correlates with geographic range size. Our main findings are: (1) these three rare species generally have lower genetic diversity than more abundant oaks; (2) in some cases, small population size and geographic range correlate with genetic diversity and differentiation; and (3) genetic diversity currently protected in botanic gardens is inadequately predicted by geographic range size and number of samples preserved, suggesting non-random sampling of populations for conservation collections. Our results highlight that most populations of these three rare oaks have managed to avoid severe genetic erosion, but their small size will likely necessitate genetic management going forward.

scholarly journals Avifauna of Saurashtra University Campus, Rajkot, Gujarat, India

2020 ◽  
Vol 12 (13) ◽  
pp. 16764-16774
Author(s):  
Varsha Trivedi ◽  
Sanjay Vaghela
Keyword(s):  
Species Richness ◽  
Population Density ◽  
Population Size ◽  
Rare Species ◽  
Bird Species ◽  
Species Density ◽  
Ecological Indices ◽  
University Campus ◽  
High Species Richness ◽  
Line Transects

We examined the avifauna of Saurashtra University Campus (SUC), Rajkot, Gujarat from July to December 2017.  The study area was divided into four sections: North (N), East (E), South (S) and West (W) and surveyed over 18 visits (four line transects/visit).  We recorded a total of 82 bird species from 67 genera, 40 families and 16 orders.  Of these 57 species were terrestrial and 25 aquatic.  By population size the most abundant birds were members of Columbidae (28%), Sturnidae (13%), and Charadridae (8%).  Seventy per cent of birds observed (n=7665) were classed as very common and 2% (n=261) as very rare.  Species density (S/N = 3.39) and population density (n/N = 196) were at their maximum in December.  Ecological indices on temporal base reveal high species richness and Simpson diversity (1/D =17.0 and 1-D= 0.942) in August and November and Shannon diversity was high (H’=3.275) in November during study period.  

scholarly journals Towards on the conservation of rare species Iris glaucescens (Iridaceae) in Novosibirsk oblast: ecoinformative multimodal analysis of the area

2020 ◽  
Vol 24 ◽  
pp. 00007
Author(s):  
Konstantin Baikov ◽  
Vladimir Doronkin
Keyword(s):  
Population Size ◽  
Rare Species ◽  
Environmental Variables ◽  
Vascular Plants ◽  
Maximum Entropy Method ◽  
Regional Model ◽  
Entropy Method ◽  
Novosibirsk Oblast ◽  
Multimodal Analysis ◽  
Local Populations

Multimodal ecoinformation analysis as an modern computative approach to geospatial investigation of biodiversity structure is performed on maximum entropy method for local populations of Iris glaucescens -rare species of vascular plants that is included in Red Book of Novosibirsk Oblast. The most informative environmental variables were ranged and examined in detail. According to obtained results, trio of the most important variables in the scale of 1/12 arc-degree (5.0 arc-minutes) global model, includes: 1) maximum average diurnal tempreature of surface air in the warmest period of an year (bio5) – 32.7%, annual mean temperature of surface air (bio1) – 11.2%, and maximum average diurnal tempreature of surface air in July (tmax7) – 9.0%. Three of the most important variables in the scale of 1/60 arc-degree (1.0 arc-minutes) regional model (Zone_18) are: maximum average diurnal tempreature of surface air in the warmest period of a year (bio5) -35.7%, maximum average diurnal tempreature of surface air in Juny (tmax6) – 23.1%, minimum average diurnal tempreature of surface air in October (tmin10) – 7,7%. Therefore, climatic variables that influense on the amount of heat in the warmest period of a year, may be taken into account as factors, limiting population size of I. glaucescens.

scholarly journals The inherent multidimensionality of temporal variability: how common and rare species shape stability patterns

2019 ◽  
Vol 22 (10) ◽  
pp. 1557-1567 ◽  
Author(s):  
Jean‐François Arnoldi ◽  
Michel Loreau ◽  
Bart Haegeman
Keyword(s):  
Rare Species ◽  
Temporal Variability ◽  
Shape Stability

scholarly journals The inherent multidimensionality of temporal variability: How common and rare species shape stability patterns

2018 ◽  
Author(s):  
Jean-François Arnoldi ◽  
Michel Loreau ◽  
Bart Haegeman
Keyword(s):  
Rare Species ◽  
Temporal Variability ◽  
Species Abundance ◽  
Common Species ◽  
Ecological Communities ◽  
Shape Stability ◽  
Abundance Pattern ◽  
Stochastic Perturbations ◽  
Environmental Perturbations ◽  
Stability Concepts

AbstractEmpirical knowledge of ecosystem stability and diversity-stability relationships is mostly based on the analysis of temporal variability of population and ecosystem properties. Variability, however, often depends on external factors that act as disturbances, making it difficult to compare its value across systems and relate it to other stability concepts. Here we show how variability, when viewed as a response to stochastic perturbations, can reveal inherent stability properties of ecological communities, with clear connections with other stability notions. This requires abandoning one-dimensional representations, in which a single variability measurement is taken as a proxy for how stable a system is, and instead consider the whole set of variability values associated to a given community, reflecting the whole set of perturbations that can generate variability. Against the vertiginous dimensionality of the perturbation set, we show that a generic variability-abundance pattern emerges from community assembly, which relates variability to the abundance of perturbed species. As a consequence, the response to stochastic immigration is governed by rare species while common species drive the response to environmental perturbations. In particular, the contrasting contributions of different species abundance classes can lead to opposite diversity-stability patterns, which can be understood from basic statistics of the abundance distribution. Our work shows that a multidimensional perspective on variability allows one to better appreciate the dynamical richness of ecological systems and the underlying meaning of their stability patterns.

scholarly journals Population extinctions driven by climate change, population size, and time since observation may make rare species databases inaccurate

2018 ◽  
Author(s):  
Thomas Kaye ◽  
Matt A Bahm ◽  
Andrea S Thorpe ◽  
Erin C Gray ◽  
Ian Pfingsten ◽  
...  
Keyword(s):  
Climate Change ◽  
Population Size ◽  
Rare Species ◽  
Biological Diversity ◽  
Extinction Risk ◽  
Climate Change Impacts ◽  
Small Population ◽  
Population Extinction ◽  
Population Sizes ◽  
Potential Signal

Loss of biological diversity through population extinctions is a global phenomenon that threatens many ecosystems. Managers often rely on databases of rare species locations to plan land use actions and conserve at-risk taxa, so it is crucial that the information they contain is accurate and dependable. However, climate change, small population sizes, and long gaps between surveys may be leading to undetected extinctions of many populations. We used repeated survey records for a rare but widespread orchid, Cypripedium fasciculatum (clustered lady's slipper), to model population extinction risk based on elevation, population size, and time between observations. Population size was negatively associated with extinction, while elevation and time between observations interacted such that low elevation populations were most vulnerable to extinction, but only over larger time spans. We interpret population losses at low elevations as a potential signal of climate change impacts. We used this model to estimate the probability of persistence of populations across California and Oregon, and found that 31%-56% of the 2415 populations reported in databases from this region are likely extinct. Managers should be aware that the number of populations of rare species in their databases is potentially an overestimate, and consider resurveying these populations to document their presence and condition, with priority given to older reports of small populations, especially those at low elevations or in other areas with high climate vulnerability.

scholarly journals Resilience, Invariability, and Ecological Stability across Levels of Organization

2016 ◽  
Author(s):  
Bart Haegeman ◽  
Jean-François Arnoldi ◽  
Shaopeng Wang ◽  
Claire de Mazancourt ◽  
José M. Montoya ◽  
...  
Keyword(s):  
Rare Species ◽  
Temporal Variability ◽  
Empirical Studies ◽  
Complete Loss ◽  
Theoretical Studies ◽  
Loss Of Stability ◽  
Stability Studies ◽  
Ecological Stability ◽  
Broad Concept ◽  
Variable Species

AbstractEcological stability is a bewildering broad concept. The most common stability measures are asymptotic resilience, widely used in theoretical studies, and measures based on temporal variability, commonly used in empirical studies. We construct measures of invariability, defined as the inverse of variability, that can be directly compared with asymptotic resilience. We show that asymptotic resilience behaves like the invariability of the most variable species, which is often a rare species close to its extinction boundary. Therefore, asymptotic resilience displays complete loss of stability with changes in community composition. In contrast, mean population invariability and ecosystem invariability are insensitive to rare species and quantify stability consistently whether details of species composition are considered or not. Invariability provides a consistent framework to predict diversity-stability relationships that agree with empirical data at population and ecosystem levels. Our findings can enhance the dialogue between theoretical and empirical stability studies.

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