scholarly journals Habitat suitability – density relationship in an endangered woodland species: the case of the Blue Chaffinch (Fringilla polatzeki)

2017 ◽  
Author(s):  
Luis M. Carrascal ◽  
Angel C. Moreno ◽  
Alejandro Delgado ◽  
Víctor Suárez ◽  
Domingo Trujillo
Keyword(s):  
Population Size ◽  
Habitat Suitability ◽  
Management Practices ◽  
Habitat Preferences ◽  
Pine Forests ◽  
Tree Cover ◽  
Distribution Model ◽  
Gran Canaria ◽  
Western Palearctic ◽  
Local Abundance

Background. Understanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs. Methods. We studied the Gran Canaria blue chaffinch (Fringilla polatzeki), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994. Results. The variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July-September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195-430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic. Discussion. Habitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.

scholarly journals Habitat suitability – density relationship in an endangered woodland species: the case of the Blue Chaffinch (Fringilla polatzeki)

2017 ◽  
Author(s):  
Luis M. Carrascal ◽  
Angel C. Moreno ◽  
Alejandro Delgado ◽  
Víctor Suárez ◽  
Domingo Trujillo
Keyword(s):  
Population Size ◽  
Habitat Suitability ◽  
Management Practices ◽  
Habitat Preferences ◽  
Pine Forests ◽  
Tree Cover ◽  
Distribution Model ◽  
Gran Canaria ◽  
Western Palearctic ◽  
Local Abundance

Background. Understanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs. Methods. We studied the Gran Canaria blue chaffinch (Fringilla polatzeki), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994. Results. The variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July-September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195-430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic. Discussion. Habitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.

scholarly journals Habitat suitability—density relationship in an endangered woodland species: the case of the Blue Chaffinch (Fringilla polatzeki)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3771 ◽  
Author(s):  
Luis M. Carrascal ◽  
Ángel C. Moreno ◽  
Alejandro Delgado ◽  
Víctor Suárez ◽  
Domingo Trujillo
Keyword(s):  
Population Size ◽  
Habitat Suitability ◽  
Management Practices ◽  
Habitat Preferences ◽  
Pine Forests ◽  
Tree Cover ◽  
Distribution Model ◽  
Gran Canaria ◽  
Western Palearctic ◽  
Local Abundance

BackgroundUnderstanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs.MethodsWe studied the Gran Canaria blue chaffinch (Fringilla polatzeki), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994.ResultsThe variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July–September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195–430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic.DiscussionHabitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.

scholarly journals Stand Structure and Local Landscape Variables Are the Dominant Factors Explaining Shrub and Tree Diversity in Mediterranean Forests

2021 ◽  
Vol 13 (21) ◽  
pp. 11658
Author(s):  
Siba Ghadban ◽  
Aitor Ameztegui ◽  
Marcos Rodrigues ◽  
Cristina Chocarro ◽  
Fermín Alcasena ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Management Practices ◽  
Environmental Changes ◽  
Stand Structure ◽  
National Forest Inventory ◽  
Landscape Patterns ◽  
Pine Forests ◽  
Tree Cover ◽  
Mediterranean Forests ◽  
Large Trees

Plant diversity is a core value of forests and is rapidly becoming a primary management goal under the threat of global environmental changes. Changing conditions, including forestry interventions, or lack of them, may endanger its preservation. Abandonment of management in forests previously subjected to a multipurpose silviculture and secondary succession is hypothesized to have altered the biodiverse Mediterranean forests in recent years and affected plant diversity. We used data in national forest inventory plots and local landscape ecology metrics from forest cartography, combined with artificial neural networks, to predict richness and Shannon diversity indices for the tree and shrub layers of several Mediterranean forest types. We found that richness and diversity depend on forest structure and on local landscape patterns, and also, though to a lesser degree, on site conditions (mainly soil pH), but not on forest intervention. In order to benefit plant diversity in the forest landscapes analyzed, forest management practices need to promote diameter variety, the presence of large trees, tree cover, variation in the height of trees and shrubs, and a heterogeneous local landscape at the stand level. Aleppo pine forests and Scots pine forests showed more consistent results in their models than cork oak and black pine forests, both of which require further research.

scholarly journals Projected dynamics of breeding habitat suitability for a steppe-land bird warrant anticipatory conservation actions

2021 ◽  
Author(s):  
Andrea Simoncini ◽  
Samuele Ramellini ◽  
Alexis Martineau ◽  
Alessandro Massolo ◽  
Dimitri Giunchi
Keyword(s):  
Global Change ◽  
Habitat Suitability ◽  
Species Distribution Model ◽  
Species Conservation ◽  
Temporal Variations ◽  
Breeding Habitat ◽  
Distribution Model ◽  
Spatial Density ◽  
Critical Areas ◽  
Western Palearctic

Understanding spatial and temporal variations of habitat suitability is fundamental for species' conservation under global change. Steppic species are particularly sensitive to anthropogenic change and have undergone large declines in the last decades. We aimed to describe current and future breeding habitat suitability for the Eurasian stone-curlew Burhinus oedicnemus, a steppic species of conservation concern, and to identify critical areas for its conservation. We collected 1628 presence records covering the period 1992-2016. We developed a species distribution model using a dynamic Maxent algorithm and a set of pseudo-absences with a spatial density weighted on a fixed kernel density estimated on the presences, to mitigate the potential sampling bias. We projected this model under a set of carbon emission, socioeconomic and land-use/land-cover scenarios for the years 2030, 2050, 2070 and 2090. Finally, we described the cell-wise and mean change of breeding habitat suitability through consecutive time intervals and identified the areas critical for the species' conservation. All scenarios predicted a short-term northward shift of suitable areas, followed by a period of stability. We found no consistent trends in the mean change of breeding habitat suitability, and similar extents of suitable areas under current and future scenarios. Critical areas for the conservation of the species are mainly located in Northern Europe, Israel and parts of North Africa, the Iberian Peninsula and Italy. According to our results, the Eurasian stone-curlew has the potential to maintain viable populations in the Western Palearctic, but dispersal limitations might hinder the colonization of shifted suitable areas. Targeted conservation interventions in the critical areas are therefore recommended to secure the future of the species under global change.

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

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. 

scholarly journals Effect of Pheromone Blend Components, Sex Ratio, and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae)

2020 ◽  
Vol 20 (6) ◽  
Author(s):  
Abeysinghe Mudiyanselage Prabodha Sammani ◽  
Dissanayaka Mudiyanselage Saman Kumara Dissanayaka ◽  
Leanage Kanaka Wolly Wijayaratne ◽  
William Robert Morrison
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Management Practices ◽  
Mating Disruption ◽  
Current Knowledge ◽  
Mating Status ◽  
Cadra Cautella ◽  
Synthetic Chemicals ◽  
Population Sizes ◽  
Lepidoptera Pyralidae

Abstract The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.

Distribution and habitat preference of protected reindeer lichen species (Cladonia arbuscula, C. mitis and C. rangiferina) in the Balaton Uplands (Hungary)

2021 ◽  
Vol 53 (3) ◽  
pp. 271-282
Author(s):  
Mónika Sinigla ◽  
Erzsébet Szurdoki ◽  
László Lőkös ◽  
Dénes Bartha ◽  
István Galambos ◽  
...  
Keyword(s):  
Vascular Plants ◽  
Management Practices ◽  
Soil Depth ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Canopy Cover ◽  
Lichen Species ◽  
Oak Forests ◽  
Natural Habitats ◽  
Cladonia Rangiferina

AbstractThe maintenance of protected lichen species and their biodiversity in general depends on good management practices based on their distribution and habitat preferences. To date, 10 of the 17 protected lichen species of Hungary have been recorded in the Bakony Mts including the Balaton Uplands region. Habitat preferences of three protected Cladonia species (C. arbuscula, C. mitis and C. rangiferina) growing on underlying rocks of red sandstone, basalt, Pannonian sandstone and gravel were investigated by detailed sampling. We recorded aspect, underlying rock type, soil depth, pH and CaCO3 content, habitat type (as defined by the General National Habitat Classification System Á-NÉR), all species of lichen, bryophyte and vascular plants as well as percentage cover of exposed rock, total bryophytes, lichens, vascular plants and canopy, degree of disturbance and animal impacts. Sporadic populations of these species mostly exist at the top of hills and mountains in open acidofrequent oak forests, but they may occur in other habitats, such as closed acidofrequent oak forests, slope steppes on stony soils, siliceous open rocky grasslands, open sand steppes, wet and mesic pioneer scrub and dry Calluna heaths. Cladonia rangiferina was found to grow beneath higher canopy cover than either C. arbuscula or C. mitis in the Balaton Uplands. Furthermore, there were significant differences in canopy cover between occupied and unoccupied quadrats in the case of all three species. Cladonia rangiferina is a good indicator species of natural habitats in Hungary due to its restricted distribution and low ecological tolerance. These results may lead to the adoption of effective conservation methods (e.g. game exclusion, artificial dispersal) in the future.

scholarly journals A Bioclimate-Based Maximum Entropy Model for Comperiella calauanica Barrion, Almarinez and Amalin (Hymenoptera: Encyrtidae) in the Philippines

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 26
Author(s):  
Billy Joel M. Almarinez ◽  
Mary Jane A. Fadri ◽  
Richard Lasina ◽  
Mary Angelique A. Tavera ◽  
Thaddeus M. Carvajal ◽  
...  
Keyword(s):  
Maximum Entropy ◽  
Habitat Suitability ◽  
Species Distribution Model ◽  
Biological Control Agent ◽  
The Philippines ◽  
Distribution Model ◽  
Field Surveys ◽  
Probability Of Occurrence ◽  
Precipitation Seasonality ◽  
Bioclimatic Variables

Comperiella calauanica is a host-specific endoparasitoid and effective biological control agent of the diaspidid Aspidiotus rigidus, whose outbreak from 2010 to 2015 severely threatened the coconut industry in the Philippines. Using the maximum entropy (Maxent) algorithm, we developed a species distribution model (SDM) for C. calauanica based on 19 bioclimatic variables, using occurrence data obtained mostly from field surveys conducted in A. rigidus-infested areas in Luzon Island from 2014 to 2016. The calculated the area under the ROC curve (AUC) values for the model were very high (0.966, standard deviation = 0.005), indicating the model’s high predictive power. Precipitation seasonality was found to have the highest relative contribution to model development. Response curves produced by Maxent suggested the positive influence of mean temperature of the driest quarter, and negative influence of precipitation of the driest and coldest quarters on habitat suitability. Given that C. calauanica has been found to always occur with A. rigidus in Luzon Island due to high host-specificity, the SDM for the parasitoid may also be considered and used as a predictive model for its host. This was confirmed through field surveys conducted between late 2016 and early 2018, which found and confirmed the occurrence of A. rigidus in three areas predicted by the SDM to have moderate to high habitat suitability or probability of occurrence of C. calauanica: Zamboanga City in Mindanao; Isabela City in Basilan Island; and Tablas Island in Romblon. This validation in the field demonstrated the utility of the bioclimate-based SDM for C. calauanica in predicting habitat suitability or probability of occurrence of A. rigidus in the Philippines.

scholarly journals Riparian forestry management and adult stream insects

2004 ◽  
Vol 8 (3) ◽  
pp. 545-549 ◽  
Author(s):  
R. A. Briers ◽  
J. H. R. Gee
Keyword(s):  
Riparian Vegetation ◽  
Management Practices ◽  
Food Sources ◽  
Tree Cover ◽  
Strong Impact ◽  
Riparian Management ◽  
Stream Insects ◽  
Larval Stages ◽  
Forestry Management ◽  
Coniferous Plantation

Abstract. The impacts of coniferous plantation forestry on the biology of upland streams in the UK are firmly established. Whilst benthic communities have been well studied, very little research has considered the impacts of riparian forestry management on adult stream insects, yet the essentially terrestrial adult (reproductive) phase may be important in determining the abundance and distribution of larval stages. Riparian vegetation has a potentially strong impact on survival and success of adult stages through alteration of microclimate, habitat structure and potential food sources, in addition to effects carried over from larval stages. Here, current riparian management strategies are analysed in the light of available information on the ecology of adult stream insects. On the whole, management practices appear to favour adult stream insects, although an increase in tree cover in riparian areas could be beneficial, by providing more favourable microclimatic conditions for adults. This conclusion is drawn based on rather limited information, and the need for further research into the effects of riparian forestry management on adult stream insects is highlighted. Keywords: microclimate, plantation, life history, riparian vegetation

scholarly journals NOTES ON THE ECOLOGY OF THE COLOMBIAN LEAFTOED GECKO (PHYLLODACTYLUS TRANSVERSALIS), ENDEMIC TO MALPELO ISLAND

2016 ◽  
Vol 42 (2) ◽  
Author(s):  
Mateo López Victoria ◽  
Matthias Jurczyk ◽  
Volkmar Wolters
Keyword(s):  
Population Size ◽  
Breeding Season ◽  
Habitat Preference ◽  
Habitat Preferences ◽  
Original Description ◽  
Tropical Pacific ◽  
Reference Points ◽  
Eastern Tropical Pacific ◽  
Reptile Species ◽  
Malpelo Island

The Colombian leaf-toed gecko (Phyllodactylus transversalis) is the least known reptile species of Malpelo Island (Eastern Tropical Pacific). In the 37 years since its original description, no single study strictly dedicated to this species has been conducted. With the goal of providing information on the ecology and population size of this gecko, data collected during two visits to the island are presented. Behavior and reproduction were studied by following individuals during the night and by searching for hidden individuals and eggs during the day. Population’s density and habitat preferences were estimated by classifying the island’s surfaces into four types and counting geckos inside those habitats within band transects. General morphological measurements of geckos were performed as reference points for future comparisons. Phyllodactylus transversalis lays its eggs in narrow crevices of rocks, apparently communally. Reproduction seems to take place during most of the year, probably associated with the peak breeding season of seabirds. Although conspecifics shared shelters during the day, densities during the night suggest no apparent habitat preference for foraging. Population size of this species was estimated at approximately 114000 individuals.

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