Ehsan Rahimi

Dr. Ehsan Rahimi

Andong National University, Andong, Gyeongbuk, Republic of Korea
orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 February 2025 in Environments
Verified
Journal Article
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Ehsan RahimiEhsan Rahimi
Ehsan Rahimi
Pinliang DongPinliang Dong
Pinliang Dong
CJChuleui Jung
Chuleui Jung
While numerous studies have investigated the NDVI-LST relationship at local or regional scales, existing global analyses are outdated and fail to incorporate recent environmental changes driven by climate change and human activity. This study aims to address this gap by conducting an extensive global analysis of NDVI-LST correlations from 2000 to 2024, utilizing multi-source satellite data to assess latitudinal and ecosystem-specific variability. The MODIS dataset, which provides global daily LST data at a 1 km resolution from 2000 to 2024, was used alongside MODIS-derived NDVI data, which offers global vegetation indices at a 1 km resolution and 16-day temporal intervals. A correlation analysis was performed by extracting NDVI and LST values for each raster cell. The analysis revealed significant negative correlations in regions such as the western United States, Brazil, southern Africa, and northern Australia, where increased temperatures suppress vegetation activity. A total of 38,281,647 pixels, or 20% of the global map, exhibited statistically significant correlations, with 80.4% showing negative correlations, indicating a reduction in vegetation activity as temperatures rise. The latitudinal distribution of significant correlations revealed two prominent peaks: one in the tropical and subtropical regions of the Southern Hemisphere and another in the temperate zones of the Northern Hemisphere. This study uncovers notable spatial and latitudinal patterns in the LST-NDVI relationship, with most regions exhibiting negative correlations, underscoring the cooling effects of vegetation. These findings emphasize the crucial role of vegetation in regulating surface temperatures, providing valuable insights into ecosystem health, and informing conservation strategies in response to climate change.

16 January 2022 in Agriculture & Food Security
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Journal Article
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Ehsan RahimiEhsan Rahimi
Ehsan Rahimi
SBShahindokht Barghjelveh
Shahindokht Barghjelveh
PDPinliang Dong
Pinliang Dong
Background: The world's growing population and growing need for food have increased attention to urban agriculture around the world. Most crops grown in urban environments need bees for pollination. However, little is known about bee populations in urban areas and little attention has been paid to the function of these pollinators in cities. Therefore, studying the ecology of pollinating bees in urban gardens and green roofs contributes greatly to urban agriculture. In this study, the results of 87 articles related to the presence of bees in gardens and urban farms were summarized in three general sections. The first part deals with issues, such as the diversity of bees in urban gardens, dominant species in these areas, their nesting type, origin, specialty, and sociality. The second part examines the attractiveness of host plants in urban gardens and farms and their origin for bees. The third section examines the effects of landscape and local variables effects on the presence of bees in urban farms and gardens.Results: Our data showed that urban environments, especially urban gardens, contain a high diversity of bees, which honeybees and bumblebees are the most dominant species in these environments. The results of the second part showed that native plants were more attractive to bees than non-native plants. In the third section, most studies have shown the negative role of urbanization on the presence of bees. On the other hand, many studies have shown that the presence of green spaces or other farms and gardens around the studied gardens have a positive effect on the presence of pollinators.Conclusion: Urban environments have a high diversity of plants and bees that provides a good opportunity to increase agricultural production in these environments. Planting native plants and creating artificial nests for solitary bees and bumblebees can help attract more bees to urban environments. Converting lawns into floral resources or carrying out agricultural activities around green spaces can also effectively help to increase agricultural production in the city.

11 February 2024 in Insects
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Journal Article
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Ehsan RahimiEhsan Rahimi
Ehsan Rahimi
CJChuleui Jung
Chuleui Jung
Bees represent vital natural assets contributing significantly to global food production and the maintenance of ecosystems. While studies on climate change effects impacting major pollinators like honeybees and bumblebees raise concerns about global diversity and crop productivity, comprehensive global-scale analyses remain limited. This study explores the repercussions of global warming on 1365 bees across seven families of bees worldwide. To compile a robust global bee occurrence dataset, we utilized the innovative ‘BeeBDC’ R package that amalgamated over 18.3 million bee occurrence records sourced from various repositories. Through species distribution models under the SSP585 scenario in the year 2070, we assessed how climate change influences the climate suitability of bees on a global scale, examining the impacts across continents. Our findings suggested that approximately 65% of bees are likely to witness a decrease in their distribution, with reductions averaging between 28% in Australia and 56% in Europe. Moreover, our analysis indicated that climate change’s impact on bees is projected to be more severe in Africa and Europe, while North America is expected to witness a higher number (336) of bees expanding their distribution. Climate change’s anticipated effects on bee distributions could potentially disrupt existing pollinator–plant networks, posing ecological challenges that emphasize the importance of pollinator diversity, synchrony between plants and bees, and the necessity for focused conservation efforts.

13 November 2021 in Journal of Ecology and Environment
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Journal Article
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Ehsan RahimiEhsan Rahimi
Ehsan Rahimi
SBShahindokht Barghjelveh
Shahindokht Barghjelveh
Pinliang DongPinliang Dong
Pinliang Dong
Background: Landscape metrics have been widely applied to quantifying the relationship between land surface temperature and urban spatial patterns and have received acceptable verification from landscape ecologists but some studies have shown their inaccurate results. The objective of the study is to compare landscape metrics and texture-based measures as alternative indices in measuring urban heterogeneity effects on LST at multiple scales. Results: The statistical results showed that the correlation between urban landscape heterogeneity and LST increased as the spatial extent (scale) of under-study landscapes increased. Overall, landscape metrics showed that the less fragmented, the more complex, larger, and the higher number of patches, the lower LST. The most significant relationship was seen between edge density (ED) and LST (r = − 0.47) at the sub-region scale. Texture measures showed a stronger relationship (R2 = 34.84% on average) with LST than landscape metrics (R2 = 15.33% on average) at all spatial scales, meaning that these measures had a greater ability to describe landscape heterogeneity than the landscape metrics. Conclusion: This study suggests alternative measures for overcoming landscape metrics shortcomings in estimating the effects of landscape heterogeneity on LST variations and gives land managers and urban planners new insights into urban design.

10 September 2021 in Journal of Ecology and Environment
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Journal Article
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Ehsan RahimiEhsan Rahimi
Ehsan Rahimi
SBShahindokht Barghjelveh
Shahindokht Barghjelveh
PDPinliang Dong
Pinliang Dong
Background: Recent declines in bee populations, along with increasing demand for pollination services in urban, agricultural, and natural environments, have led to strategies to attract wild bees to these areas. One of these strategies is installing artificial nests adjacent to urban gardens and agricultural farms. Bee hotels and nest boxes are among the artificial nests used by gardeners and farmers to attract pollinators. In this paper, we reviewed 50 studies that reported the efficiency of nest boxes and bee hotels in attracting bees. We considered the maximum occupation rate (percentage) as the main index to evaluate the efficiency of artificial nests. Results: The maximum occupation rate of bee hotels was higher in farms (averaged 44.1%) than in forests (averaged 30.3%) and urban (averaged 38.3%) environments. In the case of nest boxes, most studies reported efficiencies of less than 20%, with an occupation rate of 16% and 5.5% on average in forest and urban environments respectively. However, our meta-analysis results showed that there was no significant relationship between the occupation rate of the nests and their installation place. Regression analysis also showed that the structural features of bee hotels (length and diameter) and nest boxes (volume and entrance size) did not affect their efficiency in attracting bees. Conclusion: Our data showed that the strategy of installing artificial nests to attract pollinators is successful only concerning bee hotels, and the use of nest boxes has not been very successful.

21 January 2022 in Agriculture & Food Security
Verified
Journal Article
Open access
PDF file
Ehsan RahimiEhsan Rahimi
Ehsan Rahimi
SBShahindokht Barghjelveh
Shahindokht Barghjelveh
Pinliang DongPinliang Dong
Pinliang Dong
Background: The growing human population and the need for more food in the world have reduced forests and turned them into agricultural land. Many agricultural products are dependent on pollinating bees, so it is possible to increase crop production by increasing the population of bees in agricultural landscapes and preventing further deforestation. In agricultural landscapes, bees use forest patches as nesting habitats and, therefore, are highly dependent on these patches. Therefore, by creating new forest patches within agricultural fields, we can increase the pollination rate, and thus the crop production. In this regard, understanding the role of forest patches and their effects on bee populations is a key step in successfully implementing the patch creation strategy. To determine the effects of forest patches on bees and pollination services, we reviewed 93 articles examining the effects of forest patches on bees in agricultural landscapes. We divided these effects into three categories based on the sampling method: (1) distance-dependent, (2) amount, and (3) structural effects. Methods: We searched for published studies related to the effects of the forest patches on bees in agricultural landscapes using the ISI Web of Science. We conducted our search from May 1991 to May 2021 using the following search string keywords: forest fragment, forest patch, forest fragmentation, pollination, and bee. Results: Approximately, 79% of studies showed that by increasing the distance (up to 2 km) from forest patches, regardless of the type of species, the type of agricultural product around the patches, the size and number of patches, the bees’ diversity and abundance decrease. Approximately, 76% of the studies showed that the presence of forest cover within a radius of 2 km from the target sites has a positive effect on bee populations. Our data also show that larger forest patches maintain a larger population of bees than smaller ones. Conclusion: It was not clear what percentage of a landscape should be covered by forest or how much habitat was sufficient to maintain a viable population of bees. Therefore, we suggest future studies to find the thresholds of forest amounts below which the bee population is rapidly declining.