Faculty Opinions recommendation of Ecological specialization and population size in a biodiversity hotspot: how rare species avoid extinction.

'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.

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Comparing Genetic Diversity in Three Threatened Oaks

Forests ◽

10.3390/f12050561 ◽

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.

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Avifauna of Saurashtra University Campus, Rajkot, Gujarat, India

Journal of Threatened Taxa ◽

10.11609/jott.5113.12.13.16764-16774 ◽

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.

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

BIO Web of Conferences ◽

10.1051/bioconf/20202400007 ◽

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.

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

10.1101/506006 ◽

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.

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

PLoS ONE ◽

10.1371/journal.pone.0210378 ◽

2019 ◽

Vol 14 (10) ◽

pp. e0210378 ◽

Cited By ~ 1

Author(s):

Thomas N. Kaye ◽

Matt A. Bahm ◽

Andrea S. Thorpe ◽

Erin C. Gray ◽

Ian Pfingsten ◽

...

Keyword(s):

Climate Change ◽

Population Size ◽

Rare Species

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

Oikos ◽

10.2307/3545230 ◽

1990 ◽

Vol 58 (3) ◽

pp. 385 ◽

Cited By ~ 2

Author(s):

Thomas W. Schoener

Keyword(s):

Population Size ◽

Rare Species ◽

Temporal Variability

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Modeling habitat suitability of the Red-backed Shrike (Lanius collurio) in the Irano-Anatolian biodiversity hotspot

Journal of Zoological Research ◽

10.30564/jzr.v3i2.2897 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Sayyad Sheykhi Ilanloo ◽

Sohrab Ashrafi ◽

Afshin Alizadeh Shabani

Keyword(s):

Population Size ◽

Habitat Suitability ◽

Anthropogenic Activities ◽

Important Variable ◽

Biodiversity Hotspot ◽

Mean Annual Temperature ◽

Suitable Habitat ◽

Suitable Model ◽

Western Palearctic ◽

Suitable Habitats

Identifying suitable habitats of species is essential knowledge to conserve them successfully. Human activities causes the reduction of population size and habitat suitability of many species. Red-backed Shrike is a widespread in western Palearctic. However, the population of this specie has declined in its geographical range due to the loss of suitable habitats. Therefore, it is necessary to identify its suitable habitats and factors affecting species habitat suitability and to protect its reduction population size. The aim of the present study was to identify the suitable habitat of the Red-backed Shrike and determine the most important predictors of its suitable habitat in Irano-Anatolian biodiversity hotspot. To achieve this goal, species presence points were first collected and seven environmental variables related to climate, topography and anthropogenic activities, were used to construct the species habitat suitable model. Models were built using five distribution modeling methods: Maxent, GAP, GLM, RF and GBM in sdm package. Then the models were Ensemble from 5 different models and the final model was constructed. The results of this study showed that the most suitable habitats of this species are in the western and northern parts of the area of study. The mean annual temperature with 41% contribution was the most important variable in constructing the habitat suitability model for this specie. In addition, climate variables with 75% contribution were identified as the most important habitat suitability factor for this specie. Also in relation to conservation of the Red-backed Shrike species in the Irano-Anatolian region, it can be stated that the extent of distribution and presence of this specie has been extended to the northern latitudes due to climate change. As a result, the temperature and climate factor should be given special attention in the management of bird habitats in this area.

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Інтегральна оцінка стану популяцій рідкісних видів рослин

Ukrainian Journal of Ecology ◽

10.15421/2017_37 ◽

2017 ◽

Vol 7 (2) ◽

pp. 201-209

Author(s):

G. Klimenko ◽

A. Kovalenko ◽

Yu. Lykholat ◽

N. Khromykh ◽

O. Didur ◽

...

Keyword(s):

Population Density ◽

Population Size ◽

Plant Species ◽

Rare Species ◽

Field Size ◽

Rare Plant ◽

Population Status ◽

Plant Populations ◽

Ontogenetic Structure ◽

Vital Structure

The decline in the global biodiversity and the increase in the number of threatened plant species are the extremely unfavorable trends over the past decades. These phenomena determined the need for the thorough and detailed study of the plant population resistance mechanisms, and the development of the methods to predict the risks of their extinction. In the recent years, simultaneous assessment of the ontogenetic and the vital structure of the populations has become the most recognized method of studying populations. This approach has provided a significant increase in the reliability assessment of the population status and led to improved predictions of their dynamics. However, there are a limited number of the papers containing the complex demographic analysis, including the field size of the population, the number of individuals in the population, the population density, as well as genetic, ontogenetic, and vital structure of the populations with their dynamics. The purpose of this work was to determine the current state and to predict the possible trends in the status of seven rare plant species’ populations located on the territory of the National Nature Park “Desnyansko-Starogutsky” (Sumy province, Ukraine). Rare plants Epipactis helleborine (L.) Crantz, Lilium martogon L., Listera ovata (L.) R. Br., Platanthera chlorantha (Cust.) Rchb., and Pulsatilla patens (L.) Mill. are the species listed in the Red Book of Ukraine. Plant species Circaea alpina L. and Pyrola chlorantha Sw. are designated as the rare species on the territory of Sumy region. Integral estimation of the population status has based on the determination of such parameters as population size, population density, the ontogenetic index, and the index of the population vitality. Correlation analysis revealed a high level of correlation (r = 0. 99) not between everyone, but between some of the population parameters only. In our study, the indices that characterize the ontogenetic structure of the populations were the most frequently correlated: renewal index, generative index, as well as indexes of the population age (Δ) and the effectiveness of the population (ω). The regression analysis revealed that the long-term monitoring of the rare plant populations will be an integral character in the case of accounting for such factors as the population size and density dynamics over the years, changes in the population vitality (Q), and the annual changes of the magnitude of ω, which integrates the ontogenetic structure of the populations. It has been established that the populations of L. martagon from the phytocenoses of Pinetum coryloso-maіanthemosum and Fraxinetum coryloso-convallariosum were stable enough together with the progressive development trend. The populations of the rare species C. alpina, L. martagon (habitat between Betuleta corylosa and Pineta corylosa-convallariosum), and P. patens were estimated as the sustainable. A clear tendency toward a decrease in the individuals’ number was found in rare species represented by only one population (L. ovata, P. chlorantha, and Pl. chlorantha), as well as in one of the several populations of the species C. alpina and E. helleborine. It was confirmed, that the dynamics of the rare plant populations is influenced not only by the internal population processes. The external ecological and coenotic factors, including the ones of a catastrophic nature, which are associated with the succession processes, as well as the level of wildlife conservation in the natural areas of Ukraine can be of decisive importance.

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