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21.
Tradable biodiversity credit systems provide flexible means to resolve conflicts between development and conservation land-use
options for habitats occupied by threatened or endangered species. We describe an approach to incorporate the influence of
habitat fragmentation into the conservation value of tradable credits. Habitat fragmentation decreases gene flow, increases
rates of genetic drift and inbreeding, and increases probabilities of patch extinction. Importantly, tradable credit systems
will change the level of fragmentation over time for small and/or declining populations. We apply landscape equivalency analysis
(LEA), a generalizable, landscape-scale accounting system that assigns conservation value to habitat patches based on patch
contributions to abundance and genetic variance at landscape scales. By evaluating habitat trades using two models that vary
the relationship between dispersal behaviors and landscape patterns, we show that LEA provides a novel method for limiting
access to habitat at the landscape-scale, recognizing that the appropriate amount of migration needed to supplement patch
recruitment and to offset drift and inbreeding will vary as landscape pattern changes over time. We also found that decisions
based on probabilities of persistence alone would ignore changes in migration, genetic drift, and patch extinction that result
from habitat trades. The general principle of LEA is that habitat patches traded should make at least equivalent contributions
to rates of recruitment and migration estimated at a landscape scale. Traditional approaches for assessing the “take” and
“jeopardy” standards under the Endangered Species Act based on changes in abundance and probability of persistence may be
inadequate to prevent trades that increase fragmentation. 相似文献
22.
23.
Christiane von der Ohe Victoria Gauthier Lily Tamburic-Ilincic Anita Brule-Babel W. G. Dilantha Fernando Randy Clear Todd J. Ward Thomas Miedaner 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(3):407-417
Twenty four isolates of Fusarium graminearum, half of which were 3-acetyldeoxynivalenol (3-ADON) and half 15-acetyldeoxynivalenol (15-ADON) chemotypes, were tested for
their ability to produce deoxynivalenol and to cause Fusarium head blight (FHB) in spring wheat cultivars. The objectives
of this study were to determine (1) whether 3-ADON isolates differ in aggressiveness, as measured by the FHB index, and DON
production from 15-ADON isolates under field conditions, and (2) whether the performance of resistant host cultivars was stable
across isolates. Field tests of all isolates were conducted with three replicates at each of two locations in Canada and Germany
in 2008 with three host genotypes differing in FHB resistance level. The resistant host genotype showed resistance regardless
of the chemotype or location. The differences between mean FHB indices of 3-ADON and 15-ADON isolates were not significant
for any wheat genotype. In contrast, average DON production by the 3-ADON isolates (10.44 mg kg−1) was significantly (P < 0.05) higher than for the 15-ADON isolates (6.95 mg kg−1) at three of the four locations where moderately resistant lines were tested, and at both locations where susceptible lines
were evaluated. These results indicate that 3-ADON isolates could pose a greater risk to food safety. However, as the mean
aggressiveness and DON production of 3-ADON and 15-ADON chemotypes was similar on highly resistant lines, breeding and use
of highly resistant lines is still the most effective measure of reducing the risks associated with DON in wheat. 相似文献
24.
Cristina E. Almeida-Naranjo Patricio J. Espinoza-Montero Marcelo I. Muñoz-Rodríguez Cristina A. Villamar-Ayala 《Water, air, and soil pollution》2017,228(7):253
Hydraulic retention time (HRT) influence improving sludge flocculation with adding the polyelectrolytes (non-ionic, anionic, and cationic) was studied on an activated sludge (AS) system fed with synthetic domestic wastewater (SDW), dairy industry wastewater (DIW), and caramel industry wastewater (CIW). The sludge volumetric index, food/microorganism ratio (F/M), and mixed liquor volatile suspended solids at different HRTs (6, 8 and 10 h) were monitored on an experimental model. Results showed that both SDW and IW had the best sludge flocculation conditions at 8 h and 100 mL of non-ionic polyelectrolyte (0.2 mg L?1). In addition, this phenomenon reached the organic matter removal efficiencies of 95.9, 95.7, and 94.2% for SDW, DIW, and CIW, respectively. Therefore, optimum HRT increased the organic matter removal efficiencies by 10%, sludge concentration by 37% (22–55%), and F/M ratio by 70%. Moreover, the polyelectrolytes used in AS improved the sludge flocculation by 2.9 times. 相似文献
25.
Neutral models for testing landscape hypotheses 总被引:5,自引:0,他引:5
Neutral landscape models were originally developed to test the hypothesis that human-induced fragmentation produces patterns
distinctly different from those associated with random processes. Other uses for neutral models have become apparent, including
the development and testing of landscape metrics to characterize landscape pattern. Although metric development proved to
be significant, the focus on metrics obscured the need for iterative hypothesis testing fundamental to the advancement of
the discipline. We present here an example of an alternative neutral model and hypothesis designed to relate the process of
landscape change to observed landscape patterns. The methods and program, QRULE, are described and options for statistical
testing outlined. The results show that human fragmentation of landscapes results in a non-random association of land-cover
types that can be describe by simple statistical methods. Options for additional landscape studies are discussed and access
to QRULE described in the hope that these methods will be employed to advance our understanding of the processes that affect
the structure and function in human dominated landscapes. 相似文献
26.
Ferreira SR Araújo JV Braga FR Araujo JM Carvalho RO Silva AR Frassy LN Freitas LG 《Tropical animal health and production》2011,43(3):639-642
The ovicidal effect of the nematophagous fungus Pochonia chlamydosporia on eggs of Ascaris suum was tested under laboratory conditions. A. suum eggs were plated on 2% water–agar with seven fungal isolates (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4)
and control without fungus. After 5, 7, 10, 14, 15 and 21 days of incubation, approximately 100 eggs were removed from the
plates and classified according to the following parameters: type 1, biochemical and physiological effect without morphological
damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect
with morphological alteration of eggshell and embryo showing hyphal penetration and internal egg colonization. The isolates
effectively destroyed A. suum eggs and all types of effects were observed during the experiment. There was no variation in ovicidal capacity (type 3 effect)
among the isolates (p > 0.05) throughout the experiment. After 21 days, isolate 5 showed the highest percentages of type 3 effect (58.33%). The
results indicated that P. chlamydosporia (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) can destroy A. suum eggs and is, therefore, a potential biological control agent of nematodes. 相似文献
27.
Jemberu Dessie Solomon Melaku Firew Tegegne Kurt J. Peters 《Tropical animal health and production》2010,42(5):841-848
The experiment consisting of 7 days of digestibility and 90 days of feeding trial was conducted at Wogda (Ethiopia) to determine
the effect of supplementation of graded levels of concentrate mix (CM) on feed intake, digestibility, and body weight (BW)
change in hay-based feeding of Simada sheep. Twenty-yearling Simada sheep with a mean initial BW of 17.9 ± 0.81 kg (mean ±
SD) were used in randomized complete block design arranged into five blocks of four animals. The four dietary treatments that
consisted of hay alone (T1), hay +150 g dry matter (DM; T2, low), hay +250 g DM (T3, medium), and hay +350 g DM (T4, high)
CM were randomly assigned to each sheep within a block. The CM consisted of wheat bran (WB), noug seed (Guizotia abyssinica) meal and safflower (Carthamus tinctorius) seed meal at the ratio of (2:1:1), respectively. Supplementation with T2 and T3 increased (P < 0.001) total DM and organic matter intake than the control treatment. Overall, supplementation improved (P < 0.001) crude protein intake, digestibility, feed conversion efficiency, BW gain, and profitability compared to the control,
whereas sheep on the high than the low and medium level of supplementation performed better in these parameters among the
supplemented treatments. From the results of this study, T4 is recommended as the best level of supplementation since it resulted
in better nutrient utilization, animal performance, and profitability. 相似文献
28.
Tomoko Suzuki Shougo Nishimura Kazuhiro Yagi Ryousuke Nakamura Yoshihiro Takikawa Yoshinori Matsuda Koji Kakutani Teruo Nonomura 《Phytoparasitica》2018,46(1):31-43
The lengths of conidiophores in fungal colonies of the melon powdery mildew pathogen Podosphaera xanthii Pollacci KMP-6 N cultured under greenhouse (natural) conditions differed markedly from those cultured in a growth chamber. We hypothesized that light wavelength was responsible for the differences in conidiophore length. In this study, we examined the effects of light-emitting diode (LED) irradiation (purple, blue, green, orange, and red light) and white light on colony development and conidiophore formation in KMP-6 N using a stereomicroscope and a high-fidelity digital microscope. Colonies on leaves were flat under greenhouse conditions and under red LED light irradiation but were stacked under growth chamber conditions and under purple, blue, green, and orange LED light irradiation. In addition, KMP-6 N formed catenated conidia comprising six conidia per conidiophore under greenhouse conditions and red light but more than seven conidia per conidiophore under growth chamber conditions and purple, blue, green, and orange light. Furthermore, almost none of the conidia on top of the conidiophores grown under blue light were fully constricted. Therefore, these fungi could not scatter their conidia and spread infection. This is the first report of the effects of LED lights on conidiophore formation in the melon powdery mildew fungus P. xanthii. The results provide insight into the mechanisms underlying the responses of conidiophores to light of specific wavelengths and conidial scatter from conidiophores of melon powdery mildew fungi. 相似文献
29.
Shima Bagherabadi Doustmorad Zafari Yousef Moradi Amirabad Joyce H. C. Woudenberg 《Journal of General Plant Pathology》2017,83(6):398-401
Drimia maritima (squill) is a historically important medicinal plant. During the spring of 2016, small, yellow leaf spots, which became brown and finally necrotic, were observed on squill plants in Kohgiluyeh and Boyer-Ahmad Provinces in Iran. A fungus was consistently isolated from infected leaves and identified as Alternaria alternata based on morphological and phylogenetic analyses. Pathogenicity tests confirmed A. alternata to be the causal agent of the newly observed leaf spot disease. This is the first report of leaf spot on D. maritima caused by A. alternata in the world. 相似文献
30.
Ricardo Rocha Milou Groenenberg Paulo E. D. Bobrowiec Mar Cabeza Jorge M. Palmeirim Christoph F. J. Meyer 《Landscape Ecology》2017,32(1):31-45