Tolerance of tropical seagrasses Zostera muelleri and Halophila ovalis to burial: Toward an understanding of threshold effects

2019 ◽  
Vol 218 ◽  
pp. 131-138 ◽  
Author(s):  
Claudia F. Benham ◽  
Sara G. Beavis ◽  
Emma L. Jackson
Keyword(s):  
Threshold Effects ◽  
Halophila Ovalis

Is More Invariably Better?: Threshold Effects of Firefighters' Social Support

2007 ◽  
Author(s):  
Monique M. Mendoza ◽  
Jennifer K. Shannon ◽  
Shiloh E. Jordan ◽  
Yuhong He ◽  
David Tager ◽  
...  
Keyword(s):  
Social Support ◽  
Threshold Effects

PEMETAAN SEBARAN PADANG LAMUN MENGGUNAKAN CITRA SATELIT LANDSAT 8 DI KEPULAUAN TANIMBAR KABUPATEN MALUKU TENGGARA BARAT PROVINSI MALUKU

2019 ◽  
Vol 3 ◽  
pp. 871
Author(s):  
Desita Anggraeni ◽  
M. Nurkholis Fauzi ◽  
Christian Novia Ngesti H.
Keyword(s):  
Landsat 8 ◽  
Surface Reflectance ◽  
Halophila Ovalis ◽  
Halodule Uninervis ◽  
Gap Data

Padang lamun merupakan habitat penting pesisir yang memiliki peran kunci dalam ekosistem pesisir. Kawasan ini merupakan area asuhan bagi ikan-ikan kecil, udang, persembunyian biota dari predatornya, pendaur zat hara, serta penyerap nutrien dari limpasan air laut yang dapat membantu menstabilkan sedimen dan kejernihan air. Kepulauan Tanimbar merupakan salah satu lokasi di Provinsi Maluku dengan potensi sebaran lamun yang cukup luas, namun informasi mengenai sebaran lamun di kawasan ini tidak terdata dengan baik. Teknologi penginderaan jauh merupakan salah satu alternatif untuk mengisi gap data di area yang luas dan sulit dijangkau, termasuk untuk memetakan sebaran lamun di Kepulauan Tanimbar. Penelitian ini bertujuan untuk menyediakan data dasar sebaran dan luas habitat lamun di pesisir Kepulauan Tanimbar. Metode yang digunakan adalah analisis citra penginderaan jauh Landsat 8, menerapkan penajaman citra untuk perairan dangkal menggunakan algoritma Lyzenga. Citra Landsat yang digunakan Landsat Surface Reflectance liputan path/row 106/65 dan 106/66 tahun perekaman 2017. Pengambilan data lapangan dilakukan pada tanggal 1-10 November 2017. Metode pengambilan data lamun dilakukan menggunakan metode seagrass watch . Hasil pengolahan citra menunjukkan lamun terdistribusi merata di seluruh pesisir Kepulauan Tanimbar dengan luas total 5.615,63 hektar dengan tutupan terpadat di sekitar Pulau Seira. Hasil survei lapangan menunjukkan tutupan lamun terpadat dijumpai di Formusan dengan tutupan lamun rata-rata 95%. Kondisi lamun paling baik berada di daerah Sabal, didukung kondisi air yang sangat jernih dengan substrat utama pasir. Berdasarkan hasil pengamatan lapangan, jenis lamun yang ditemukan antara lain: E n h alu s a c o r oid e s , T h ala s sia h e m p ric hii, C y m o d o c e a s e r r ula t a , C y m o d o c e a rotundata, Syringodi um isoetifolium, Halodule uninervis, Halophila ovalis, dan Halophila minor .

Kestabilan Habitat Lamun Ditinjau Dari Komposisi dan Kepadatan Jenis

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Paskalina Th. Lefaan
Keyword(s):  
Line Transect ◽  
Seagrass Habitat ◽  
Pioneer Species ◽  
Thalassia Hemprichii ◽  
Climax Species ◽  
Halophila Ovalis ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium ◽  
Cymodocea Serrulata ◽  
Stable Habitat

<em>Seagrasses habitats have both physical and ecological functions that support adjacent waters qualities and its dwelling organisms. There are varies of pressure on seagrass environmental, especially due to people activities that could decrease its function and habitat stabilities. The study aimed to determine about seagrass habitat stabilities from its species composition and/or densities. Line transect-plots and exploration methods were used in five locations of Manokwari coastal waters, that were, Andai, Rendani, Wosi, Briosi, and Tanjung Manggewa. There are five pioneer species (Cymodocea rotundata, Halodule pinifolia, H. uninervis, Syringodium isoetifolium, Halophila ovalis) and 3 climax species (Cymodocea serrulata, Enhalus acoroides, Thalassia hemprichii). The pioneer only found in Andai and Wosi, however both pioneer and climax encountered in three other locations. In Rendani and Tanjung Manggewa higher density of climax species (T. hemprichii) were 617.7 and 828.0 stands m-2, respectively, although in Briosi the higher pioneer (C. rotundata) of 570.7 stands m-2. These conditions showed that seagrass habitat in Rendani and Tanjung Manggewa are more stable compared to Briosi, as well as Andai and Wosi. It concluded that pioneer species found in newly formed habitat or disturbed, on the other hand, climax in more stable habitat.</em>

Evaluating Threshold Effects in Consumer Sentiment

2004 ◽  
Vol 70 (4) ◽  
pp. 942-952
Author(s):  
Brigitte Desroches ◽  
Marc‐André Gosselin
Keyword(s):  
Threshold Effects ◽  
Consumer Sentiment

scholarly journals Threshold Effects of Infectious Disease Outbreaks on Livestock Prices: Cases of African Swine Fever and Avian Influenza in South Korea

2021 ◽  
Vol 11 (11) ◽  
pp. 5114
Author(s):  
Hyung-Chul Rah ◽  
Hyeon-Woong Kim ◽  
Aziz Nasridinov ◽  
Wan-Sup Cho ◽  
Seo-Hwa Choi ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Infectious Diseases ◽  
Disease Outbreaks ◽  
African Swine Fever ◽  
Threshold Effect ◽  
Impact Response ◽  
Threshold Effects ◽  
Infectious Disease Outbreaks ◽  
Retail Prices ◽  
The Impact

In this paper we demonstrate the threshold effects of infectious diseases on livestock prices. Daily retail prices of pork and chicken were used as structured data; news and SNS mentions of African Swine Fever (ASF) and Avian Influenza (AI) were used as unstructured data. Models were tested for the threshold effects of disease-related news and SNS frequencies, specifically those related to ASF and AI, on the retail prices of pork and chicken, respectively. The effects were found to exist, and the values of ASF-related news on pork prices were estimated to be −9 and 8, indicating that the threshold autoregressive (TAR) model can be divided into three regimes. The coefficients of the ASF-related SNS frequencies on pork prices were 1.1666, 0.2663 and −0.1035 for regimes 1, 2 and 3, respectively, suggesting that pork prices increased by 1.1666 Korean won in regime 1 when ASF-related SNS frequencies increased. To promote pork consumption by SNS posts, the required SNS frequencies were estimated to have impacts as great as one standard deviation in the pork price. These values were 247.057, 1309.158 and 2817.266 for regimes 1, 2 and 3, respectively. The impact response periods for pork prices were estimated to last 48, 6, and 8 days for regimes 1, 2 and 3, respectively. When the prediction accuracies of the TAR and autoregressive (AR) models with regard to pork prices were compared for the root mean square error, the prediction accuracy of the TAR model was found to be slightly better than that of the AR. When the threshold effect of AI-related news on chicken prices was tested, a linear relationship appeared without a threshold effect. These findings suggest that when infectious diseases such as ASF occur for the first time, the impact on livestock prices is significant, as indicated by the threshold effect and the long impact response period. Our findings also suggest that the impact on livestock prices is not remarkable when infectious diseases occur multiple times, as in the case of AI. To date, this study is the first to suggest the use of SNS to promote meat consumption.

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