scholarly journals Spatial and temporal partitioning and tree preference in California woodland ants

2019 ◽  
Author(s):  
Dylan MacArthur-Waltz ◽  
Rebecca Nelson ◽  
Gail Lee ◽  
Deborah M. Gordon
Keyword(s):  
Niche Overlap ◽  
Time Of Day ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Deciduous Trees ◽  
Ant Communities ◽  
Quercus Agrifolia ◽  
Temporal Partitioning ◽  
Ant Community ◽  
Exotic Trees

AbstractSpatial and temporal partitioning of habitat may facilitate diversity and have important impacts on ant communities. To investigate niche overlap in an ant community in a northern California oak woodland, we observed ant foraging on trees in 4 seasonal surveys, each lasting 2 weeks, in a 9.5-hectare plot over the course of a year. Foraging activity in all 5 observed ant species differed by season, time of day, and/or the genera of trees used. Of the 3 ant species most frequently observed, Camponotus semitestaceus was most active during spring and summer nights, Formica moki was most active during spring and summer days, and Prenolepis imparis was most active during both day and night of fall and winter. All ant species preferred native trees to exotic trees and preferred evergreen trees to deciduous trees. Our results suggest that native evergreen oaks such as Quercus agrifolia, currently threatened by sudden oak death (Phytophthora ramorum), may be important for supporting ant biodiversity.

scholarly journals Tree Preference and Temporal Activity Patterns for a Native Ant Community in an Urbanized California Woodland

2021 ◽  
Author(s):  
Dylan J. MacArthur-Waltz ◽  
Rebecca A. Nelson ◽  
Gail Lee ◽  
Deborah M. Gordon
Keyword(s):  
Activity Patterns ◽  
Active Species ◽  
Northern California ◽  
Ant Communities ◽  
Evergreen Species ◽  
Quercus Agrifolia ◽  
Temporal Partitioning ◽  
Ant Community ◽  
Urban Woodland ◽  
Ant Diversity

AbstractAnthropogenic disturbances, including land use change and exotic species, can alter the diversity and dynamics of ant communities. To examine foraging behavior in an urbanized habitat in northern California, we surveyed the presence of 9 ant species on 876 trees across 4 seasons during both day and night in a 9.5-hectare urbanized oak-exotic woodland. Ants were more likely to be observed on native, evergreen trees, suggesting that native evergreen species may help maintain ant diversity. Species showed clear patterns of temporal partitioning of foraging activity. Ant species varied in their use of native evergreen Quercus agrifolia trees across season and day/night axes. Of the 3 ant species most frequently observed, Camponotus semitestaceus was most active during spring and summer nights, Formica moki was most active during spring and summer days, and Prenolepis imparis was most active during both day and night during fall and winter. Liometopum occidentale was the second most active species during summer day and night, and winter day. Our findings demonstrate that an oak-exotic urban woodland in Northern California was able to maintain a native ant community, and strong temporal partitioning within that community.

scholarly journals Constitutive phenolic biomarkers identify naïve Quercus agrifolia resistant to Phytophthora ramorum, the causal agent of sudden oak death

2017 ◽  
Vol 37 (12) ◽  
pp. 1686-1696 ◽  
Author(s):  
Anna O Conrad ◽  
Brice A McPherson ◽  
David L Wood ◽  
Laurence V Madden ◽  
Pierluigi Bonello
Keyword(s):  
Seasonal Variation ◽  
Phenolic Compounds ◽  
Disease Management ◽  
Disease Susceptibility ◽  
Natural Populations ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Quercus Agrifolia ◽  
Forest Pathogen ◽  
Live Oak

Abstract Sudden oak death, caused by the invasive pathogen Phytophthora ramorum Werres, de Cock & Man in't Veld, can be deadly for Quercus agrifolia Neé (coast live oak, CLO). However, resistant trees have been observed in natural populations. The objective of this study was to examine if pre-attack (constitutive) levels of phenolic compounds can be used as biomarkers to identify trees likely to be resistant. Naïve trees were selected from a natural population and phloem was sampled for analysis of constitutive phenolics. Following P. ramorum inoculation, trees were phenotyped to determine disease susceptibility and constitutive phenolic biomarkers of resistance were identified. Seasonal variation in phloem phenolics was also assessed in a subset of non-inoculated trees. Four biomarkers, including myricitrin and three incompletely characterized flavonoids, together correctly classified 80% of trees. Biomarker levels were then used to predict survival of inoculated CLO and the proportion of resistant trees within a subset of non-inoculated trees from the same population. Levels of five phenolics were significantly affected by season, but with no pronounced variation in average levels among seasons. These results suggest that pre-infection levels of specific phenolic compounds (i.e., biomarkers) can identify trees naturally resistant to this invasive forest pathogen. Knowledge of resistant trees within natural populations may be useful for conserving and breeding resistant trees and for disease management.

scholarly journals A Summary of North American Hardwood Tree Diseases with Bleeding Canker Symptoms

2007 ◽  
Vol 33 (2) ◽  
pp. 122-131
Author(s):  
A.H. Nelson ◽  
G.W. Hudler
Keyword(s):  
North American ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Deciduous Trees ◽  
Tree Diseases ◽  
Hardwood Tree ◽  
Available Information

Although the presence of bleeding cankers on deciduous trees may raise fears of the presence of Phytophthora ramorum, the cause of sudden oak death, other pathogens also cause similar symptoms. This review of hardwood tree diseases with bleeding canker symptoms provides an overview of available information of these diseases, providing a diagnosis guide as well as a stimulus for continued research in these areas.

scholarly journals Phytophthora ramorum as the Cause of Extensive Mortality of Quercus spp. and Lithocarpus densiflorus in California

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 205-214 ◽  
Author(s):  
D. M. Rizzo ◽  
M. Garbelotto ◽  
J. M. Davidson ◽  
G. W. Slaughter ◽  
S. T. Koike
Keyword(s):  
The Netherlands ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Central Coast ◽  
Outer Bark ◽  
Canker Disease ◽  
Quercus Agrifolia ◽  
Lithocarpus Densiflorus ◽  
Quercus Spp ◽  
Diagnostic Symptoms

A new canker disease, commonly known as sudden oak death, of Lithocarpus densiflorus, Quercus agrifolia, Q. kelloggii, and Q. parvula var. shrevei in California is shown to be caused by Phytophthora ramorum. The pathogen is a recently described species that previously was known only from Germany and the Netherlands on Rhododendron spp. and a Viburnum sp. This disease has reached epidemic proportions in forests along approximately 300 km of the central coast of California. The most consistent and diagnostic symptoms on trees are cankers that develop before foliage symptoms become evident. Cankers have brown or black discolored outer bark and seep dark red sap. Cankers occur on the trunk at the root crown up to 20 m above the ground, but do not enlarge below the soil line into the roots. Individual cankers are delimited by thin black lines in the inner bark and can be over 2 m in length. In L. densiflorus saplings, P. ramorum was isolated from branches as small as 5 mm in diameter. L. densiflorus and Q. agrifolia were inoculated with P. ramorum in the field and greenhouse, and symptoms similar to those of naturally infected trees developed. The pathogen was reisolated from the inoculated plants, which confirmed pathogenicity.

Ant community structure along an extended rain forest–savanna gradient in tropical Australia

2008 ◽  
Vol 24 (4) ◽  
pp. 445-455 ◽  
Author(s):  
Laura T. van Ingen ◽  
Ricardo I. Campos ◽  
Alan N. Andersen
Keyword(s):  
Community Structure ◽  
Rain Forest ◽  
Habitat Type ◽  
Ant Communities ◽  
Savanna Woodland ◽  
Ant Community ◽  
Open Forest ◽  
Forest Regrowth ◽  
Tropical Australia ◽  
Ant Community Structure

AbstractIn mixed tropical landscapes, savanna and rain-forest vegetation often support contrasting biotas, and this is the case for ant communities in tropical Australia. Such a contrast is especially pronounced in monsoonal north-western Australia, where boundaries between rain forest and savanna are often extremely abrupt. However, in the humid tropics of north-eastern Queensland there is often an extended gradient between rain forest and savanna through eucalypt-dominated tall open forest. It is not known if ant community structure varies continuously along this gradient, or, if there is a major disjunction, where it occurs. We address this issue by sampling ants at ten sites distributed along a 6-km environmental gradient from rain forest to savanna, encompassing the crest and slopes of Mt. Lewis in North Queensland. Sampling was conducted using ground and baited arboreal pitfall traps, and yielded a total of 95 ant species. Mean trap species richness was identical in rain forest and rain-forest regrowth, somewhat higher in tall open forest, and twice as high again in savanna woodland. The great majority (78%) of the 58 species from savanna woodland were recorded only in this habitat type. MDS ordination of sites based on ant species composition showed a continuum from rain forest through rain-forest regrowth to tall open forest, and then a discontinuity between these habitat types and savanna woodland. These findings indicate that the contrast between rain forest and savanna ant communities in tropical Australia is an extreme manifestation of a broader forest-savanna disjunction.

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)).

Forest transformation resulting from an exotic pathogen: regeneration and tanoak mortality in coast redwood stands affected by sudden oak death

2011 ◽  
Vol 41 (4) ◽  
pp. 763-772 ◽  
Author(s):  
Benjamin S. Ramage ◽  
Kevin L. O’Hara ◽  
Alison B. Forrestel
Keyword(s):  
Canopy Cover ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Coast Redwood ◽  
Marin County ◽  
Wildlife Species ◽  
Management Interventions ◽  
Redwood Forests ◽  
Exotic Pathogen ◽  
Notholithocarpus Densiflorus

Sudden oak death is dramatically altering forests throughout coastal California, but little is known about the communities that are assembling in affected areas. This emerging disease, caused by the exotic pathogen Phytophthora ramorum (S. Werres, A.W.A.M. de Cock), has had especially severe effects on tanoak ( Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh), a broadleaf evergreen that is abundant in forests dominated by coast redwood ( Sequoia sempervirens (D.Don) Endl.). Tanoak, a valuable food source to numerous wildlife species, is unlikely to successfully regenerate in diseased areas, and thus, affected redwood forests are transitioning to a novel state. In this study, to predict which species might replace tanoak, we investigated regeneration patterns in heavily impacted stands in Marin County, California. Our main findings were as follows: (i) despite reductions in canopy cover, there is no evidence that any species other than tanoak has exhibited a regenerative response to tanoak mortality, (ii) the regeneration stratum was dominated by redwood and tanoak (other tree species were patchy and (or) scarce), and (iii) some severely affected areas lacked sufficient regeneration to fully re-occupy available growing space. Our results indicate that redwood is likely to initially re-occupy the majority of the ground relinquished by tanoak, but also provide evidence that longer-term trajectories are unresolved, and may be highly responsive to management interventions.

scholarly journals Disease on Nursery Stock as Affected by Environmental Factors and Seasonal Inoculum Levels of Phytophthora ramorum in Stream Water Used for Irrigation

Plant Disease ◽  
2008 ◽  
Vol 92 (11) ◽  
pp. 1566-1573 ◽  
Author(s):  
S. A. Tjosvold ◽  
D. L. Chambers ◽  
S. T. Koike ◽  
S. R. Mori
Keyword(s):  
Stream Water ◽  
Disease Incidence ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Nursery Stock ◽  
Stream Sampling ◽  
Flow Through ◽  
High Concentrations ◽  
Electronic Sensors ◽  
Native Host

A pear bait monitoring system was used to detect and quantify Phytophthora ramorum propagules in streams that flow through woodland areas with sudden oak death in Santa Cruz County, CA from 2001 to 2007. Stream propagules were detected most frequently or occurred in highest concentrations in winter and spring. The stream propagule concentration was characterized with statistical models using temperature and rainfall variables from 2004 to 2007. The highest concentrations of propagules occurred when stream sampling was preceded by about 2 months with low maximum daily temperatures and by 4 days with high rainfall. The occurrence of propagules in streams in the summer was mostly associated with infected leaves from the native host Umbellaria californica that prematurely abscised and fell into the water. When the stream water was used for irrigating rhododendron nursery stock from 2004 to 2007, disease occurred only three times in the two wettest springs (2005 and 2006) on plants sprinkler irrigated with stream water with relatively high concentrations of propagules. Disease incidence was described with a statistical model using the concentration of infective propagules as measured by pear baiting and consecutive hours of leaf wetness measured by electronic sensors at rhododendron height. The concentration of infective propagules was significantly reduced after water was pumped from the stream and applied through sprinklers.

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