scholarly journals Transmission of Phytophthora ramorum in Mixed-Evergreen Forest in California

2005 ◽  
Vol 95 (5) ◽  
pp. 587-596 ◽  
Author(s):  
Jennifer M. Davidson ◽  
Allison C. Wickland ◽  
Heather A. Patterson ◽  
Kristen R. Falk ◽  
David M. Rizzo
Keyword(s):  
Leaf Litter ◽  
Disease Transmission ◽  
Rainy Season ◽  
Forest Type ◽  
Phytophthora Ramorum ◽  
Green Leaf ◽  
Evergreen Forest ◽  
Infested Soil ◽  
Live Oak ◽  
Dispersal Distances

During 2001 to 2003, the transmission biology of Phytophthora ramorum, the causal agent of sudden oak death, was studied in mixedevergreen forest, a common forest type in northern, coastal California. Investigation of the sources of spore production focused on coast live oak (Quercus agrifolia) and bay laurel (Umbellularia californica), dominant hosts that comprised 39.7 and 46.2% of the individuals at the study site, respectively. All tests for inoculum production from the surface of infected coast live oak bark or exudates from cankers were negative. In contrast, sporangia and chlamydospores were produced on the surface of infected bay laurel leaves. Mean number of zoospores produced from infected bay laurel leaves under natural field conditions during rainstorms was 1,173.0 ± SE 301.48, and ranged as high as 5,200 spores/leaf. P. ramorum was recovered from rainwater, soil, litter, and streamwater during the mid- to late rainy season in all 3 years of the study. P. ramorum was not recovered from sporadic summer rains or soil and litter during the hot, dry summer months. Concentrations of inoculum in rainwater varied significantly from year to year and increased as the rainy season progressed for the two complete seasons that were studied. Potential dispersal distances were investigated for rainwater, soil, and streamwater. In rainwater, inoculum moved 5 and 10 m from the inoculum source. For soil, transmission of inoculum was demonstrated from infested soil to bay laurel green leaf litter, and from bay laurel green leaf litter to aerial leaves of bay laurel seedlings. One-third to one-half of the hikers tested at the study site during the rainy season also were carrying infested soil on their shoes. In streamwater, P. ramorum was recovered from an unforested site in pasture ≈ 1 km downstream of forest with inoculum sources. In total, these studies provide details on the production and spread of P. ramorum inoculum in mixed-evergreen forest to aid forecasting and managing disease transmission of this environmentally destructive pathogen.

scholarly journals Survival, Dispersal, and Potential Soil-Mediated Suppression of Phytophthora ramorum in a California Redwood-Tanoak Forest

2009 ◽  
Vol 99 (5) ◽  
pp. 608-619 ◽  
Author(s):  
E. J. Fichtner ◽  
S. C. Lynch ◽  
D. M. Rizzo
Keyword(s):  
Leaf Litter ◽  
Leaf Tissue ◽  
Soil Surface ◽  
Phytophthora Ramorum ◽  
Infested Soil ◽  
Splash Dispersal ◽  
Pathogen Suppression ◽  
Rain Events ◽  
Leaf Disks

Because the role of soil inoculum of Phytophthora ramorum in the sudden oak death disease cycle is not well understood, this work addresses survival, chlamydospore production, pathogen suppression, and splash dispersal of the pathogen in infested forest soils. Colonized rhododendron and bay laurel leaf disks were placed in mesh sachets before transfer to the field in January 2005 and 2006. Sachets were placed under tanoak, bay laurel, and redwood at three vertical locations: leaf litter surface, litter–soil interface, and below the soil surface. Sachets were retrieved after 4, 8, 20, and 49 weeks. Pathogen survival was higher in rhododendron leaf tissue than in bay tissue, with >80% survival observed in rhododendron tissue after 49 weeks in the field. Chlamydospore production was determined by clearing infected tissue in KOH. Moist redwood-associated soils suppressed chlamydospore production. Rain events splashed inoculum as high as 30 cm from the soil surface, inciting aerial infection of bay laurel and tanoak. Leaf litter may provide an incomplete barrier to splash dispersal. This 2-year study illustrates annual P. ramorum survival in soil and the suppressive nature of redwood-associated soils to chlamydospore production. Infested soil may serve as primary inoculum for foliar infections by splash dispersal during rain events.

scholarly journals Forest Type Influences Transmission of Phytophthora ramorum in California Oak Woodlands

2011 ◽  
Vol 101 (4) ◽  
pp. 492-501 ◽  
Author(s):  
Jennifer M. Davidson ◽  
Heather A. Patterson ◽  
Allison C. Wickland ◽  
Elizabeth J. Fichtner ◽  
David M. Rizzo
Keyword(s):  
Forest Type ◽  
Average Length ◽  
Phytophthora Ramorum ◽  
Disease Spread ◽  
Evergreen Forest ◽  
Inoculum Production ◽  
Umbellularia Californica ◽  
Foliar Pathogen ◽  
Foliar Pathogens ◽  
Redwood Forest

The transmission ecology of Phytophthora ramorum from bay laurel (Umbellularia californica) leaves was compared between mixed-evergreen and redwood forest types throughout winter and summer disease cycles in central, coastal California. In a preliminary multisite study, we found that abscission rates of infected leaves were higher at mixed-evergreen sites. In addition, final infection counts were slightly higher at mixed-evergreen sites or not significantly different than at redwood sites, in part due to competition from other foliar pathogens at redwood sites. In a subsequent, detailed study of paired sites where P. ramorum was the main foliar pathogen, summer survival of P. ramorum in bay laurel leaves was lower in mixed-evergreen forest due to lower recovery from infected attached leaves and higher abscission rates of infected leaves. Onset of inoculum production and new infections of bay laurel leaves occurred later in mixed-evergreen forest. Mean inoculum levels in rainwater and final infection counts on leaves were higher in redwood forest. Based on these two studies, lower summer survival of reservoir inoculum in bay laurel leaves in mixed-evergreen forest may result in delayed onset of both inoculum production and new infections, leading to slower disease progress in the early rainy season compared with redwood forest. Although final infection counts also will depend on other foliar pathogens and disease history, in sites where P. ramorum is the main foliar pathogen, these transmission patterns suggest higher rates of disease spread in redwood forests during rainy seasons of short or average length.

Phytophthora ramorum. [Distribution map].

2006 ◽  
Author(s):  
Keyword(s):  
South Carolina ◽  
Phytophthora Ramorum ◽  
Distribution Map ◽  
Quercus Agrifolia ◽  
Quercus Kelloggii ◽  
Live Oak ◽  
Lithocarpus Densiflorus ◽  
Black Oak ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Phytophthora ramorum Werres, de Cock & Man in't Veld. Oomycota: Pythiales. Hosts include California black oak (Quercus kelloggii), California live oak (Quercus agrifolia), Rhododendron, shreve oak (Quercus parvula var. shrevei), tanoak (Lithocarpus densiflorus) and Viburnum. Information is given on the geographical distribution in Europe (Belgium, Denmark, France, Germany, Ireland, Italy, Netherlands, Norway, Poland, Slovenia, Spain, Sweden, Switzerland, UK) and North America (Canada (British Columbia), USA (California, Florida, Georgia, Louisiana, Oregon, South Carolina, Tennessee, Virginia, Washington)).

scholarly journals Spatial and temporal distribution in two anuran communities in the Chapada do Araripe, Northeastern Brasil

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Cristiana Ferreira-Silva ◽  
Deivid Batista de Oliveira ◽  
Herivelto Faustino de Oliveira ◽  
Robson Waldemar Ávila
Keyword(s):  
Leaf Litter ◽  
Rainy Season ◽  
Temporal Distribution ◽  
Water Bodies ◽  
Northeastern Brazil ◽  
Microhabitat Use ◽  
Spatial And Temporal Distribution ◽  
Humid Forest ◽  
Temporal Occurrence ◽  
Chapada Do Araripe

In this study, we report the temporal occurrence and habitat and microhabitat use by anurans in two areas located in one highland marsh (brejo-de-altitude) in northeastern Brazil. Fieldwork was carried out between September 2011 and September 2012. The recorded anurans belong to 14 species distributed in five families: Hylidae (six), Leptodactylidae (five), Bufonidae, Odontophrynidae and Pipidae (one each). Vocalization activity was seasonal and concentrated in the wetter and warmer months, but correlated to rainfall only in the top in the Chapada do Araripe. Richness and abundance of calling anurans were lower in the humid forest of the slope than in Cerradão area in the top of the Chapada do Araripe. Scinax x-signatus vocalized during nine months, and along with Dendropsophus soaresi, Phyllomedusa nordestina and Physalaemus cuvieri presented the longest periods of vocalization with the highest number of species vocalizing in at the height of the rainy season. Males were recorded vocalizing in nine different microhabitats, Adenomera sp. uses leaf litter and P. cuvieri the edge of water bodies as calling site both two sampled areas. Differences in richness and abundance of anurans between the two habitats are probably due to physical characteristics, such as presence of lentic environments.

The decomposition of green leaf litter is less temperature sensitive than that of senescent leaf litter: An incubation study

Geoderma ◽  
2021 ◽  
Vol 381 ◽  
pp. 114691
Author(s):  
Renshan Li ◽  
Yanzhao Zhang ◽  
Dan Yu ◽  
Yu Wang ◽  
Xingxing Zhao ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Green Leaf ◽  
Temperature Sensitive ◽  
Senescent Leaf ◽  
Incubation Study

Nocturnal Mosquitoes of Pará State in the Brazilian Amazon: Species Composition, Habitat Segregation, and Seasonal Variation

2020 ◽  
Vol 57 (6) ◽  
pp. 1913-1919
Author(s):  
Walter Santos de Araújo ◽  
Thallyta Maria Vieira ◽  
Guilherme Antunes de Souza ◽  
Isaque Clementino Bezerra ◽  
Paulo Henrique Costa Corgosinho ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Disease Transmission ◽  
Rainy Season ◽  
Mosquito Species ◽  
Species Abundance ◽  
Abundant Species ◽  
Dry Season ◽  
Habitat Segregation ◽  
Vector Species ◽  
High Degree

Abstract Mosquitoes (Diptera: Culicidae) are one of the most important disease vector species in the world. Many species have a high degree of anthropophilia and are often found in human habitations. In the present study, we have inventoried the nocturnal mosquito assemblage in intra-, peri-, and extradomicile environments in four municipalities in Pará, Brazil. At each municipality, a residence was selected and the mosquitoes were sampled using the protected human attraction capture and Shannon trap methods in April (rainy season) and August 2018 (dry season). We have collected a total of 696 mosquito specimens belonging to 8 genera and 17 species. The most abundant species were Mansonia (Mansonoides) titillans (Walker) (366/696, 52.6%), Anopheles (Nyssorhynchus) albitarsis Lynch-Arribálzaga (97/696, 13.9%), and Culex (Culex) quinquefasciatus Say (93/696, 13.4%). Mosquito richness, abundance, and composition did not differ between intra-, peri-, and extradomicile environments suggesting limited habitat segregation among the different species. However, mosquito species richness and mosquito species abundance were significantly higher during the rainy season than during the dry season, suggesting increased mosquito activity during the rainy season. We detected several important vector species of human diseases including Aedes (Stegomyia) aegypti (Linnaeus), Anopheles (Nyssorhynchus) darlingi Root, Haemagogus (Conopostegus) leucocelaenus (Dyar and Shannon), Coquillettidia (Coquillettidia) venezuelensis (Theobald), and Culex (Culex) quinquefasciatus which are the main transmitters of dengue, malaria, yellow fever, mayaro, and oropouche fever, respectively. As inventories of disease-carrying mosquitoes in the region are very scarce, mainly in residential environments, our results suggest high potential for mosquito-borne disease transmission in Pará State.

Estimating seasonal abundance and habitat use of small carnivores in the Western Ghats using an occupancy approach

2014 ◽  
Vol 30 (5) ◽  
pp. 469-480 ◽  
Author(s):  
Riddhika Kalle ◽  
Tharmalingam Ramesh ◽  
Qamar Qureshi ◽  
Kalyanasundaram Sankar
Keyword(s):  
Habitat Use ◽  
Deciduous Forest ◽  
Forest Type ◽  
Camera Trap ◽  
Dry Season ◽  
Seasonal Abundance ◽  
Evergreen Forest ◽  
Wet Season ◽  
Palm Civet ◽  
Leopard Cat

Abstract:Rigorous population studies on many small carnivores are lacking in India. Presence-absence models with habitat covariates were applied to estimate seasonal occupancy and abundance of nine small-carnivore species from camera-trap data in Mudumalai Tiger Reserve (2010 and 2011). We deployed 25 camera-trap stations in the deciduous forest, 21 in the semi-evergreen forest and 26 in the dry thorn forest. In total, 7380 trap-nights yielded 448 photographs of small carnivores: jungle cat (n = 72), leopard cat (n = 6), rusty-spotted cat (n = 11), small Indian civet (n = 89), common palm civet (n = 37), brown palm civet (n = 20), stripe-necked mongoose (n = 66), ruddy mongoose (n = 96) and Indian grey mongoose (n = 51). In the dry season, rusty-spotted cat was the rarest carnivore with an average abundance (λmean) of 0.24 ± 0.26, while ruddy mongoose was the most abundant (λmean = 0.90 ± 0.40). In the wet season, leopard cat was the rarest species (λmean = 0.048 ± 0.041) while grey mongoose was the most abundant (λmean = 0.68 ± 0.35). Abundance of jungle cat, common palm civet, ruddy mongoose and grey mongoose increased in the dry thorn forest whereas in the dry season abundance of small Indian civet decreased in this forest type. Abundance of leopard cat and small Indian civet was not influenced by habitat in the wet season. Deciduous forest was positively associated with abundance of rusty-spotted cat. Deciduous and semi-evergreen forests had a positive effect on abundance of stripe-necked mongoose while the latter was a positive predictor of abundance and occupancy for brown palm civet. Improved modelling approaches can account for the spatio-temporal variation in habitat use of small carnivores occupying specialized niches in heterogeneous tropical forests of southern India.

Monthly Litterfall Dynamics in Three Different Forest Types in Jeju Island, South Korea

2018 ◽  
Author(s):  
Ji Young An ◽  
Si Ho Han ◽  
Woo Bin Youn ◽  
Sang Ick Lee ◽  
Afroja Rahman ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Leaf Litter ◽  
Dominant Species ◽  
Forest Type ◽  
Jeju Island ◽  
Forest Composition ◽  
Forest Types ◽  
Major Pathway ◽  
Litterfall Production ◽  
High Precipitation

In a forest ecosystem, the major pathway for carbon and nutrient cycling is through litterfall, which has been influenced by physical and biological factors. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated based on precipitation and forest composition: Chungsu (<i>Quercus glauca</i> as the dominant species; low precipitation), Seonheul<sub>b</sub> (<i>Q. glauca</i> as the dominant species; high precipitation), and Seonheul<sub>m</sub> (<i>Q. glauca</i> and <i>Pinus thunbergii</i> as the dominant species; high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials. The amount of leaf litter by species varied by stand, but leaf litter and total litterfall were very similar among stands, ranging from 362 g m<sup>-2</sup> to 375 g m<sup>-2</sup> for leaf litter and 524 g m<sup>-2</sup> to 580 g m<sup>-2</sup> for total litterfall. However, oak leaf litter was the highest in May, but needle litter was the highest in December. Forest type and climate factor had no influence on the amount of litterfall in the studied forests while the litterfall production by species showed considerable seasonal variation, resulting in varying effects on carbon and nutrient cycling in these forests.

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