scholarly journals Maxent modelling for habitat suitability of vulnerable tree Dalbergia latifolia in Nepal

Silva Fennica ◽  
2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Dipak Mahatara ◽  
Amul Acharya ◽  
Bishnu Dhakal ◽  
Dipesh Sharma ◽  
Sunita Ulak ◽  
...  

Roxb., commonly known as rosewood, is one of the highly valuable tropical timber species of Nepal. The tree species was widely distributed in the past, however, over-exploitation of natural habitat, deforestation, forest conversion for agriculture, illegal logging and the invasion of alien species resulted in the classification of this species as vulnerable by the IUCN (International Union for Conservation of Nature) category. So, the prediction of habitat suitability and potential distribution of the species is required to develop restoration mechanisms and conservation interventions. In this study, we modelled the suitable habitat of over the entire possible range of Nepal using a Maxent model. We compiled 23 environmental variables (19 bioclimatic, 3 topographic and a vegetative layer), however, only 12 least correlated variables along with 43 spatially representative presence locations were retained for model prediction. We used a receiver operating characteristic (ROC) curve to assess the model’s performance and a Jackknife procedure to evaluate the relative importance of predictor variables. The model was statistically significant with an area under the curve (AUC) value of 0.969. The internal Jackknife test indicated that elevation was the most important variable for the model prediction with 71.3% contribution followed by mean temperature of driest quarter (9.8%). The most (>0.6) suitable habitat for the was 235 484 hectares with large sections of area in two provinces whereas, the western most provinces were not suitable for as per Maxent model. The information presented here can provide a framework for nature conservation planning, monitoring and habitat management of this rare and endangered species.Dalbergia latifoliaD. latifoliaD. latifoliaD. latifolia

2020 ◽  
Author(s):  
Cao Zhen ◽  
Zhang Xiaoyan ◽  
Xue Xuanji ◽  
Zhang Lei ◽  
Zhan Guanqun ◽  
...  

Abstract Background: To understand the potential distribution and habitat suitability of H. japonica in China. And to provide guidance for the wild cultivation and standardized planting of H. japonica. Methods: The maximum entropy model (Maxent) and geographic information system (ArcGIS) were applied to predict the potential suitable habitat of H. japonica species, and the contribution of variables were evaluated by using the jackknife test. Results: The AUC value confirmed the accuracy of the model prediction based on 101 occurrence records. The potential distributions of H. japonica were mainly concentrated in Jilin, Liaoning, Shaanxi and other provinces (adaptability index>0.6). Jackknife experiment showed that the precipitation of driest month (35.6%), precipitation of wettest quarter (13.4%), the mean annual temperature (7.8%) and the subclass of soil (7.8%) were the most important factors affecting the potential distribution of H. japonica. Conclusion: The niche parameters of the most suitable growth area (adaptability index>0.8) for H. japonica were precipitation of driest month (5 mm), precipitation of wettest quarter (400-490 mm), the mean annual temperature (-2-4 °C) and the subclass of soil (Glossy Chernozem, Gleyic Lime, Haplic Gypsisols).


2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Cecilia A. Veggiani Aybar ◽  
Romina A. Díaz Gomez ◽  
María J. Dantur Juri ◽  
Mercedes S. Lizarralde de Grosso ◽  
Gustavo R. Spinelli

Abstract Culicoides insignis Lutz is incriminated as a vector of bluetongue virus (BTV) to ruminants in America. In South America, almost all countries have serological evidence of BTV infections, but only four outbreaks of the disease have been reported. Although clinical diseases have never been cited in Argentina, viral activity has been detected in cattle. In this study, we developed a potential distribution map of Culicoides insignis populations in northwestern Argentina using Maximum Entropy Modeling (Maxent). For the analyses, information regarding both data of specimen collections between 2003 and 2013, and climatic and environmental variables was used. Variables selection was based on the ecological relevance in relation to Culicoides spp. biology and distribution in the area. The best Maxent model according to the Jackknife test included 53 C. insignis presence records and precipitation of the warmest quarter, altitude, and precipitation of the wettest month. Accuracy was evaluated by the area under the curve (AUC = 0.97). These results provide an important analytical resource of high potential for both the development of suitable control strategies and the assessment of disease transmission risk in the region.


2021 ◽  
Vol 13 (20) ◽  
pp. 11253
Author(s):  
Zhen Cao ◽  
Lei Zhang ◽  
Xinxin Zhang ◽  
Zengjun Guo

Hylomecon japonica is considered a natural medicinal plant with anti-inflammatory, anticancer and antibacterial activity. The assessment of climate change impact on its habitat suitability is important for the wild cultivation and standardized planting of H. japonica. In this study, the maximum entropy model (Maxent) and geographic information system (ArcGIS) were applied to predict the current and future distribution of H. japonica species, and the contributions of variables were evaluated by using the jackknife test. The area under the receiver operating characteristic curve (AUC) value confirmed the accuracy of the model prediction based on 102 occurrence records. The predicted potential distributions of H. japonica were mainly concentrated in Jilin, Liaoning, Shaanxi, Chongqing, Henan, Heilongjiang and other provinces (adaptability index > 0.6). The jackknife experiment showed that the precipitation of driest month (40.5%), mean annual temperature (12.4%), the precipitation of wettest quarter (11.6%) and the subclass of soil (9.7%) were the most important factors affecting the potential distribution of H. japonica. In the future, only under the shared socioeconomic Pathway 245 (SSP 245) scenario model in 2061–2080, the suitable habitat area for H. japonica is expected to show a significant upward trend. The area under other scenarios may not increase or decrease significantly.


Author(s):  
Laura Green ◽  
Marie-Hélène Weech ◽  
Robyn Drinkwater ◽  
Jacek Wajer

The digitisation of herbarium collections has shown to provide a growing resource in conservation science. Mobilising the data on portals such as GBIF allows researchers to access key taxonomic, habitat and geographical data that would otherwise be unavailable unless institutions are physically visited. These data are used notably in conservation assessments, distribution studies and publication of new species (Canteiro et al. 2019). The herbarium specimens held in Royal Botanic Gardens Kew, Natural History Museum, London, and the Royal Botanic Garden Edinburgh are an unparalleled resource, estimated to hold representatives of around 85% of known plant species. By working collectively for the first time on a non-type material digitisation project, the three institutions collaborated to generate data for the subtribe Phaseolinae and rosewoods totalling 37,000 legume specimens. This pilot project was made possible through Department for Environment Food & Rural Affairs (DEFRA)-allocated, Official Development Assistance (ODA) funding. This aid money is distributed by the UK government in its “global efforts to defeat poverty, tackle instability and create prosperity in developing countries”. This project focused on two case-studies: Study i. Supporting development of dry beans as a sustainable and resilient crop. Beans from the subtribe Phaseolinae, including cowpeas, lablab and wild beans, are extremely tolerant of poor-quality soils and drought. As a consequence they are particularly suitable for the low-input agricultural production systems. An estimated 14.5 million hectares of land is used for planting of cowpea each year with around 80% of that in Development Assistance Committee countries in sub Saharan Africa. Study ii. Aiding conservation and sustainable use of rosewoods and padauk (Dalbergia L.f. and Pterocarpus Jacq.). Dalbergia is distributed throughout tropical Asia, Africa and the Americas with many species being regionally endemic. Species also vary in habit from shrubs and trees to robust lianas. Pterocarpus is also pantropically distributed in a wide variety of habitats. However, suitable habitat across the natural range of these genera is now limited for many species due to a range of threats, namely deforestation, forest conversion for agriculture/human development, and logging. The timber from many species of Dalbergia and Pterocarpus has long been prized for its high-quality wood used for construction, fine furniture, cabinet work, marquetry and inlay, ethnic carvings, pianos, guitars and other musical instruments. All Dalbergia and most of the timber species of Pterocarpus are now listed on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II and the Brazilian D. nigra is listed on Appendix I. There is a huge illegal trade in these genera and serial depletion across the globe is a real and substantial risk to their survival (Winfield et al. 2016). This project used novel high-throughput methodologies and acted as a pilot study for future collaborative mass digitisation efforts. Specimens were taken from the collections, barcoded and minimal data fields captured, before high resolution images were created and the specimens returned. A subset of these was further subjected to full or partial label transcription via the use of the Atlas of Living Australia's DigiVol crowdsourcing platform or via in-house data capture. The resulting datasets will be made available via GBIF and partner sites and will be used to perform gap analyses on the collections across the institutions. We will examine the benefits of combined institutional data for these groups, assess how many species are represented in total and the geographic coverage of these collections. Use of the data will be measured by the number of downloads from GBIF and observing in-house use cases. Two research projects have just begun within Kew, using the data gathered for Pterocarpus and Lablab Adans., georeferencing for which is already underway and will contribute to conservation assessments and other measurable outputs. A data paper is planned which will also assist with tracking future use of the data set and help demonstrate the impact of the digitisation.


2020 ◽  
Author(s):  
Dol Raj Luitel ◽  
Mohan Siwakoti ◽  
Mohan D. Joshi ◽  
Muniappan Rangaswami ◽  
Pramod K. Jha

Abstract Abstract Background: Finger millet is the fourth major crop in Nepal and is cultivated in a traditional integrated subsistence system. Timely rain and appropriate temperature predominately affects crop distribution and yield. Climate change is evident in Nepal and it is imperative to understand how it affects habitat suitability of finger millet. Main objective of this study was to map the current suitable habitat and predicting the potential changes in the future under different climate scenarios in Nepal. Habitat mapping is important for maximizing production and minimizing the loss of local landraces. Results: Maxent model was used in this study to quantify the current suitable habitat and changes in the future habitat suitability of finger millet, based on representative concentration pathways (RCP)(RCP 2.6, 4.5, 6.0 and 8.5) in two different time periods (2050 and 2070AD) using climatic predictive variables and species localities. The model shows that 39.7% (58512.71km2) area of Nepal is highly suitable for finger millet, with cultivation mostly between 96-2300m above sea level. Eastern and central parts of Nepal have more suitable areas than western parts. Our research clearly shows that the future climatic suitable area of finger millet would shrink by 4.3 to 8.9% in 2050 and 8.9-10.5% under different RCPs by 2070. Conclusion: Finger millet is mostly cultivated in mid-hill terraces. The substantial increase in temperature due to climate change may be one reason for decrease in habitat suitability of finger millet. This situation would further threat loss of local landraces of finger millet in the future. The findings can help in planning and policy framing for climate resilient smart agriculture practice. Key words: Climate change, finger millet, habitat suitability, Maxent model


2019 ◽  
Author(s):  
Dol Raj Luitel ◽  
Mohan Siwakoti ◽  
Mohan D. Joshi ◽  
Muniappan Rangaswami ◽  
Pramod K. Jha

Abstract Background: Finger millet is the fourth major crop in Nepal and is cultivated in a traditional integrated subsistence system. Timely rain and appropriate temperature predominately affects crop distribution and yield. Climate change is evident in Nepal and it is imperative to understand how it affects habitat suitability of finger millet. Mapping the current suitable habitat and predicting the potential changes in the future is important for maximizing production and minimizing the loss of local landraces. Results: Maxent model was used in this study to quantify the current suitable habitat and changes in the future habitat suitability of finger millet under different climate scenarios, based on representative concentration pathways (RCP)(RCP 2.6, 4.5, 6.0 and 8.5) in two different time periods (2050 and 2070AD) using climatic predictive variables and species localities. The model shows that 39.7% (58512.71km 2 ) area of Nepal is highly suitable for finger millet, with cultivation mostly between 96-2300m above sea level. Eastern and central parts of Nepal have more suitable areas than western parts. Our research clearly shows that the future climatic suitable area of finger millet would shrink by 4.3 to 8.9% in 2050 and 8.9-10.5%under different RCPs by 2070. Conclusion: Finger millet is mostly cultivated in mid-hill terraces. The substantial increase in temperature due to climate change may be one reason for decrease in habitat suitability of finger millet. This situation would further threat loss of local landraces of finger millet in the future. The findings can help in planning and policy framing for climate resilient smart agriculture practice. Key words : Climate change, finger millet, habitat suitability, Maxent model


2019 ◽  
Vol 12 ◽  
pp. 1-10
Author(s):  
GBENGA FESTUS AKOMOLAFE ◽  
ZAKARIA BIN RAHMAD

The vast colonisation of some wetlands by Cyclosorus afer in Lafia, Nigeria has been a serious concern to ecologists and indigenous dwellers. In this study, we used the Maximum Entropy (Maxent) modelling technique to predict the habitat suitability of this fern in Lafia, Nigeria. We obtained the presence data of this fern in three already invaded wetlands of size 500 x 500m2 each using multiple 200m transect. Bioclimatic and elevation variables which were obtained from different databases were imputed into the model as predictor variables of C. afer. After that, the Maxent model was run with 70% of the presence data as training and 30% as test data. Our model result revealed that the area under the curve for receiver operating characteristics of training is 0.847 while and test data is 0.970. The model’s sensitivity was observed to be 100%. The model was assessed based on a jackknife test of individual contributions of each predictor variable to the model. Therefore, the environmental predictors of the occurrence of C. afer in this study area include precipitation seasonality, Precipitation of driest quarter, precipitation of coldest quarter and elevation. This model could be described as accurate, and the occurrence of C. afer in Lafia, Nigeria, is influenced by limiting environmental factors


2020 ◽  
Vol 7 (3) ◽  
pp. 547-552
Author(s):  
Amber Srivastava ◽  

Selaginella adunca is a quite distinct and rare species of Selaginella found in Western Himalaya. This species is reported only from few populations occurring in India and Nepal. Since most of its reported habitats are under anthropogenic pressure, therefore for proper conservation of this species it is necessary to mark the suitable habitat for its conservation and reintroduction. The present study was aimed to find out the suitable habitat of this species through ecological niche modelling (ENM) technique using Maxent model. This will also help in relocating the species in other preferred habitat type and its reintroduction as well.


2016 ◽  
Vol 27 (1) ◽  
pp. 96-110 ◽  
Author(s):  
EMMA M. SASS ◽  
JENNIFER L. MORTENSEN ◽  
J. MICHAEL REED

SummaryHabitat suitability models can guide species conservation by identifying correlates of occurrence and predicting where species are likely to occur. We created habitat suitability models for the White-breasted Thrasher Ramphocinclus brachyurus, a narrowly distributed endangered songbird that occupies dry forest in Saint Lucia and Martinique. Eighty-five percent of the global population inhabits two ranges in Saint Lucia, both of which are largely unprotected and threatened by development. We developed three habitat suitability models using Maxent techniques and published occupancy datasets collected from the species’ two Saint Lucian ranges, and used abiotic, land cover, and predator distribution predictors. We built one model with occupancy data from both ranges, and two others with occupancy data specific to each range. The best full-range model included 11 predictors; high suitability was associated with close proximity to Saint Lucia fer-de-lance Bothrops caribbeaus range, moderately low precipitation, and areas near streams. Our assessment of suitable sites island-wide was more restricted than results from a recent model that considered older land cover data and omitted predator distributions. All sites identified in our full-range model as highly suitable were in or adjacent to the species’ current designated range. The model trained on southern range occurrences predicted zero suitable habitat in the northern range, where the population is much smaller. In contrast, the model trained on northern range occurrences identified areas of moderate suitability within the southern range and patches of moderately suitable habitat in the western part of the island, where no White-breasted Thrashers currently occur. We interpret these results as suggesting that White-breasted Thrashers currently occupy virtually all suitable habitat on the island, that birds in the northern range occupy marginal habitat, or that an important correlate of suitability is missing from the model. Our results suggest that habitat management should focus on currently occupied areas.


2017 ◽  
Vol 147 (2) ◽  
Author(s):  
Sayyed Saeed Hosseinian Yousefkhani ◽  
Mansour Aliabadian ◽  
Eskandar Rastegar-Pouyani ◽  
Jamshid Darvish

Species distribution modeling is an important tool that uses ecological data to aid in biological conservation. In the present study we used prediction methods, including maximum entropy (Maxent), to project the distribution of the Persian Spider gecko and the impact of climate change on its distribution in Iran. The results were consistent between models and indicated that two of the most important variables in determining distribution of Agamura persica are mean temperature of the wettest quarter and temperature seasonality. All of the models used in this study obtained high area-under-the-curve (AUC) values. Because of the nocturnal behavior of the species, these variables can directly affect species’ activity by determining the vegetation type in habitat. Suitable habitats of Agamura persica were in two locations in eastern Iran and a third location in the central plateau. Habitat suitability for this species was increased in the last glacial maximum (LGM), at which time most parts of the Iranian Plateau were suitable (even southwest Iran). However, the suitable habitat area is restricted to the central part of the plateau in the current period. Predictions from four scenarios indicate that future habitat suitability will be patchy and that the central part of the plateau will remain the most important part of the species distribution.


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