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Giovanni Forzieri Leonardo Guarnieri Enrique R. Vivoni Fabio Castelli Federico Preti 《Forest Ecology and Management》2009,258(11):2501-2510
A canopy height model (CHM) is a standard LiDAR-derived product for deriving relevant forest inventory information, including individual tree positions, crown boundaries and plant density. Several image-processing techniques for individual tree detection from LiDAR data have been extensively described in literature. Such methods show significant performance variability depending on the vegetation characteristics of the monitored forest. Moreover, over regions of high vegetation density, existing algorithms for individual tree detection do not perform well for overlapping crowns and multi-layered forests. This study presents a new time and cost-efficient procedure to automatically detect the best combination of the morphological analysis for reproducing the monitored forest by estimating tree positions, crown boundaries and plant density from LiDAR data. The method needs an initial calibration phase based on multi attribute decision making-simple additive weighting (MADM-SAW). The model is tested over three different vegetation patterns: two riparian ecosystems and a small watershed with sparse vegetation. The proposed approach allows exploring the dependences between CHM filtering and segmentation procedures and vegetation patterns. The MADM architecture is able to self calibrate, automatically finding the most accurate de-noising and segmentation processes over any forest type. The results show that the model performances are strongly related to the vegetation characteristics. Good results are achieved over areas with a ratio between the average plant spacing and the average crown diameter (TCI) greater than 0.59, and plant spacing larger than the remote sensing data spatial resolution. The proposed algorithm is thus shown a cost effective tool for forest monitoring using LiDAR data that is able to detect canopy parameters in complex broadleaves forests with high vegetation density and overlapping crowns and with consequent significant reduction of the field surveys, limiting them over only the calibration site. 相似文献
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María Menéndez-Gutiérrez Margarita Alonso Enrique Jiménez Gabriel Toval Pedro Mansilla Adela Abelleira Andrea Abelleira-Sanmartín Raquel Díaz 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(4):939-953
Pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD), was detected in Spain in 2008. This gives rise to serious concern, as the disease has caused severe environmental and economic losses in Portugal and in Asian countries. We studied interspecific variation in susceptibility to pine wilt disease and differences in constitutive chemical compounds in the xylem tissue of the seven pine species -P. canariensis, P. halepensis, P. pinaster, P. pinea, P. sylvestris, P. radiata and P. taeda. Two-year-old trees were inoculated with B. xylophilus. Water potential and nematode densities were measured for each species on specific dates; whereas, wilting symptoms were recorded weekly until the end of the assay. Chemical compounds in the xylem were determined prior to inoculation. Three different resistance groups can be established in terms of the pine species susceptibility to PWN: non- to slightly-susceptible (P. canariensis, P. halepensis, P. taeda and P. pinea), susceptible (P. pinaster and P. radiata), and highly-susceptible (P. sylvestris). Nematodes migrated downward to the roots in all seven species. Constitutive xylem nitrogen, total polyphenols, and marginally phosphorus were negatively correlated with mortality caused by PWN. The most susceptible species, Pinus sylvestris, presented high levels of constitutive lipid-soluble substances and low levels of manganese, pointing to a possible relation between these components and PWN susceptibility. The results suggest P. sylvestris, P. pinaster and P. radiata forests could be severely damaged by PWN in Spain and highlight how constitutive chemical compounds such as nitrogen might play a role in resistance mechanisms against PWN. 相似文献
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Leandro Soares Martins Mário Fonseca Paulino Luciana Navajas Rennó Edenio Detmann Daniel Mageste de Almeida Roman Maza Ortega Deilen Paff Sotelo Moreno Javier Enrique Garces Cárdenas 《Tropical animal health and production》2017,49(8):1669-1676
The objective of the present study was to evaluate the effect of different schemes of calves’ supplementation in a creep feeding system, on the behavior of Bos indicus calves and dams, and also the influence of the calves’ supplementation on dams’ performance. Forty-eight Nellore male calves (147 ± 7 kg body weight and 3 months of age) in the suckling phase and their dams (476 ± 9 kg and 6 years of age) were studied in a completely randomized design. The experiment was divided into two periods of 71 days. The treatments were 5- and 10-g supplement dry matter (DM)/kg BW day offered in periods 1 and 2, respectively (5S/10S); 10- and 5-g supplement DM/kg BW day offered in periods 1 and 2, respectively (10S/5S); 7.5-g supplement DM/kg BW day in both periods 1 and 2 (7.5S); and mineral mix ad libitum in both periods 1 and 2 (MM). No differences (P < 0.05) in body condition score (BCS), final body weight (FBW), and average daily gain (ADG) were found in dams’ performance. Calves from MM treatment spent more time (P < 0.05) grazing than the supplemented calves from 5S/10S and 10S/5S treatments, in the first period. No difference in suckling time was found between the treatments (P > 0.05) in the first evaluated period. Calves from 10S/5S treatment spent more time suckling and less time eating supplements (P < 0.05) than 5S/10S treatment animals, in the second evaluated period. Dams of MM treatment’s calves had more idle time and lower grazing time when compared with the mothers of calves from 5S/10S and 10S/5S treatments. It was concluded that different schedules of Nellore calves’ supplementation on pasture do not affect their mothers’ performance, and supplementation decreases the grazing time of calves in the suckling phase. 相似文献
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Aline Gomes da Silva Mário Fonseca Paulino Lincoln da Silva Amorim Luciana Navajas Rennó Edenio Detmann Felipe Henrique de Moura Marcos Rocha Manso Paulo Henrique Silva e Paiva Román Enrique Maza Ortega Luciano Prímola de Melo 《Tropical animal health and production》2017,49(4):707-715
The present study was conducted to evaluate the effects of high and low supplementation levels pre- and post-weaning on performance, endocrine, metabolic, and reproductive responses of Nellore heifers. Fifty Nellore heifers with 132?±?9.9 kg average body weight (BW) and 138?±?19 days of age were supplemented from 4 to 14 months. The heifers were distributed into five supplementation plans: HH—6 g/kg of BW of supplement pre- and post-weaning, HL—6 g/kg of BW of supplement pre-weaning and 3 g/kg post-weaning, LH—3 g/kg of BW pre-weaning and 6 g/kg of BW post-weaning, LL—3 g/kg of BW pre- and post-weaning, and CC—control, no supplementation. Interactions were not significant (P?>?0.10). The level of supplement fed pre-weaning did not affect any of the performance variables evaluated at the end of the experiment (P?>?0.10). There was a significant effect of supplementation and level of supplementation fed post-weaning on average daily gain (ADG) and final BW (P?<?0.05). Overall ADG was also affected only by supplementation and level of supplement fed post-weaning (P?<?0.05) with animals receiving 6 g/kg of BW post-weaning gaining more weight. Follicular diameter was greater in animals that received 6 g/kg of BW post-weaning (P?<?0.05). In summary, performance, endocrine, metabolic, and reproductive variables evaluated in the current study were improved by the level of supplement fed post-weaning. Heifers receiving supplementation of 6 g/kg of BW post-weaning had greater responses, independent of the level received during the pre-weaning phase. 相似文献
128.
Would behavioral thermoregulation enable pregnant viviparous tropical lizards to cope with a warmer world? 下载免费PDF全文
Saúl LÓPEZ‐ALCAIDE Miguel NAKAMURA Eric N. SMITH Enrique MARTÍNEZ‐MEYER 《Integrative zoology》2017,12(5):379-395
Sceloporus lizards depend on external heat to achieve their preferred temperature (Tsel) for performing physiological processes. Evidence both in the field and laboratory indicates that pregnant females of this Genus select body temperatures (Tb) lower than 34 °C as higher temperatures may be lethal to embryos. Therefore, thermoregulation is crucial for successful embryo development. Given the increase in global air temperature, it is expected that the first compensatory response of species that inhabit tropical climates will be behavioral thermoregulation. We tested whether viviparous Sceloporus formosus group lizards in the wild exhibited differences in thermoregulatory behavior to achieve the known Tsel for developing embryos regardless of local thermal conditions. We quantified field active body temperature, thermoregulatory behavior mechanisms (time of sighting, microhabitat used and basking time) and available microhabitat thermal conditions (i.e. operative temperature) for 10 lizard species during gestation, distributed along an altitudinal gradient. We applied both conventional and phylogenic analyses to explore whether Tb or behavioral thermoregulation could be regulated in response to different thermal conditions. These species showed no significant differences in field Tb during gestation regardless of local thermal conditions. In contrast, they exhibited significant differences in their behavioral thermoregulation associated with local environmental conditions. Based on these observations, the differences in thermoregulatory behavior identified are interpreted as compensatory adjustments to local thermal conditions. We conclude that these species may deal with higher temperatures predicted for the tropics by modulating their thermoregulatory behavior. 相似文献
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Towards the identification of ecological management units: A multidisciplinary approach for the effective management of bottlenose dolphins in the southern Iberian Peninsula 下载免费PDF全文
Joan Giménez Marie Louis Enrique Barón Francisco Ramírez Philippe Verborgh Pauline Gauffier Ruth Esteban Ethel Eljarrat Damià Barceló Manuela G. Forero Renaud de Stephanis 《水产资源保护:海洋与淡水生态系统》2018,28(1):205-215