Interactions of Factors Affecting Seedling Recruitment of Blue Oak (Quercus Douglasii) in California

Ecology ◽  
1989 ◽  
Vol 70 (2) ◽  
pp. 389-404 ◽  
Author(s):  
Mark I. Borchert ◽  
Frank W. Davis ◽  
Joel Michaelsen ◽  
Lyn Dee Oyler
Keyword(s):  
Seedling Recruitment ◽  
Quercus Douglasii ◽  
Factors Affecting ◽  
Blue Oak

scholarly journals Spatiotemporal Patterns and Mechanisms of Chinese Tallowtree (Triadica sebifera) Spread along Edge Habitat in a Coastal Landscape, Mississippi, USA

2018 ◽  
Vol 11 (3) ◽  
pp. 117-126 ◽  
Author(s):  
Zhaofei Fan ◽  
Shaoyang Yang ◽  
Xia Liu
Keyword(s):  
Seed Dispersal ◽  
Negative Binomial ◽  
Seedling Recruitment ◽  
Light Availability ◽  
Spatiotemporal Patterns ◽  
Tree Age ◽  
Triadica Sebifera ◽  
Factors Affecting ◽  
Edge Habitat ◽  
Dispersal Mechanism

AbstractChinese tallowtree [Triadica sebifera(L.) Small] has reached unprecedented prevalence in coastal landscapes in the Gulf of Mexico, especially along edge habitat with low competition and abundant resource (e.g., light) availability. This study investigated the spatiotemporal patterns and mechanisms ofT. sebiferaspread along roadways and fire lines.Triadica sebiferaindividuals and landscape and community features were surveyed in equally spaced, spatially mapped plots. AllT. sebiferaindividuals were felled to determine tree age and status (seed trees or non-seed bearing trees), andT. sebiferaseed and seedling (≤2 yr old) densities and community and landscape features (over- and understory conditions, distance to seed trees) were measured. A zero-inflated negative binomial model was used to evaluate factors affectingT. sebiferaseed dispersal and seedling recruitment contributing to the observed spatiotemporal patterns. Introduced into the Grand Bay National Wildlife Refuge around 30 yr ago,T. sebiferatrees distribute in clustered patterns along roadways and fire lines and exhibit an exponential growth in density. HighT. sebiferaseed and seedling densities mainly occurred in sites that are ≤250 m from seed trees or have sparse overstory and high understory grass/herb coverage. With respect to the avian seed dispersal mechanism, the spatiotemporal patterns ofT. sebiferaspread along roadways and fire lines could be simply characterized by using landscape and community features that influence avian behaviors, including distance to seed trees, overstory tree density, and ground grass/herb coverage.

scholarly journals Hotter Drought Escalates Tree Cover Declines in Blue Oak Woodlands of California

2021 ◽  
Vol 3 ◽  
Author(s):  
Francis K. Dwomoh ◽  
Jesslyn F. Brown ◽  
Heather J. Tollerud ◽  
Roger F. Auch
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Land Surface ◽  
Climatic Variability ◽  
Tree Cover ◽  
Quercus Douglasii ◽  
Oak Woodlands ◽  
Vegetation Communities ◽  
Blue Oak ◽  
Climate Risks

California has, in recent years, become a hotspot of interannual climatic variability, recording devastating climate-related disturbances with severe effects on tree resources. Understanding the patterns of tree cover change associated with these events is vital for developing strategies to sustain critical habitats of endemic and threatened vegetation communities. We assessed patterns of tree cover change, especially the effects of the 2012–2016 drought within the distribution range of blue oak (Quercus douglasii), an endemic tree species to California with a narrow geographic extent. We utilized multiple, annual land-cover and land-surface change products from the U.S. Geological Survey (USGS) Land Change Monitoring, Assessment and Projection (LCMAP) project along with climate and wildfire datasets to monitor changes in tree cover state and condition and examine their relationships with interannual climate variability between 1985 and 2016. Here, we refer to a change in tree cover class without a land-cover change to another class as “conditional change.” The unusual drought of 2012–2016, accompanied by anomalously high temperatures and vapor pressure deficit, was associated with exceptional spikes in the amount of both fire and non-fire induced tree cover loss and tree cover conditional change, especially in 2015 and 2016. Approximately 1,266 km2 of tree cover loss and 617 km2 of tree cover conditional change were recorded during that drought. Tree cover loss through medium to high severity fires was especially large in exceptionally dry and hot years. Our study demonstrates the usefulness of the LCMAP products for monitoring the effects of climatic extremes and disturbance events on both thematic and conditional land-cover change over a multi-decadal period. Our results signify that blue oak woodlands may be vulnerable to extreme climate events and changing wildfire regimes. Here, we present early evidence that frequent droughts associated with climate warming may continue to affect tree cover in this region, while drought interaction with wildfires and the resulting feedbacks may have substantial influence as well. Consequently, efforts to conserve the blue oak woodlands, and potentially other vegetation communities in the Western United States, may benefit from consideration of climate risks as well as the potential for climate-fire and vegetation feedbacks.

scholarly journals The Effects of Different Sizes of Tree Shelters on Blue Oak (Quercus douglasii) Growth

2001 ◽  
Vol 16 (4) ◽  
pp. 153-158 ◽  
Author(s):  
Douglas D. McCreary ◽  
Jerry Tecklin
Keyword(s):  
Field Performance ◽  
Height Growth ◽  
Average Height ◽  
Quercus Douglasii ◽  
Tree Shelters ◽  
Blue Oak ◽  
Promising Tool ◽  
Wide Range ◽  
Stock Types ◽  
Time Required

Abstract Tree shelters have been used effectively in many locations to establish a wide range of tree species including oaks. However, their efficacy in Mediterranean climates like the hardwood rangelands of California has not been thoroughly tested. This study evaluated the field performance of blue oak (Quercus douglasii)—a species that is reported to be regenerating poorly in many locations in the state—protected by several sizes of tree shelters and compared response of directly sown acorns to that of 4-month-old transplants. After five growing seasons, seedlings in all sizes of tree shelters are larger than their unprotected counterparts. Tree shelters have been especially effective in promoting rapid height growth. However, regardless of tree shelter size, when seedlings grew above the tops of the shelters, average height growth diminished and diameter growth increased. Differences among stock types were relatively small, although transplants tended to perform better than directly sown acorns. These results suggest that tree shelters can greatly reduce the time required by seedlings to grow to a size where they are less vulnerable to browsing. As such, they appear to be a promising tool in efforts to regenerate blue oak in California. West. J. Appl. For. 16(4):153-158.

Competition for soil water between annual plants and blue oak (Quercus douglasii) seedlings

Oecologia ◽  
1989 ◽  
Vol 79 (4) ◽  
pp. 533-541 ◽  
Author(s):  
D. R. Gordon ◽  
J. M. Menke ◽  
K. J. Rice
Keyword(s):  
Soil Water ◽  
Annual Plants ◽  
Quercus Douglasii ◽  
Blue Oak

scholarly journals Factors affecting germination and establishment success of an endemic cactus of the Chihuahuan Desert

2020 ◽  
Author(s):  
Eder Ortiz-Martínez ◽  
Jordan Golubov ◽  
María C. Mandujano ◽  
Gabriel Arroyo-Cosultchi
Keyword(s):  
Seed Germination ◽  
Seed Bank ◽  
Developmental Stages ◽  
Seedling Recruitment ◽  
Chihuahuan Desert ◽  
Exclusion Experiment ◽  
Factors Affecting ◽  
Nurse Plants ◽  
Predator Exclusion ◽  
Storage Times

AbstractSeed and seedling are the most critical stages of cacti life cycle. From the thousands of seeds produced in a reproductive season, only a small fraction gets to germinate, the rest gets lost due to predation or gets potentially buried in the seed bank. These early stages depend on facilitation by nurse plants for germination and seedling recruitment. In this paper, we aim to describe some aspects of the recruitment of Cephalocereus polylophus. We tested the viability of seeds with different storage times as an indicator of their potential to form a short-term seed bank. Through the analysis of seed germination and seedlings survival under the canopy of two nurse plant species and open areas, we aimed to assess the importance of facilitation for recruitment. A predator exclusion experiment was used to evaluate the intensity of herbivory on seeds and seedlings of different developmental stages. Seeds had germination rates above 90%, even after two years of storage. Seed germination was only registered under one of the two nurses. After two years, up to 19% of the seedlings planted under both nurse plants survived. Protection against herbivores increased survival chances from 30 to 52 % for all age-group seedlings. Considering that facilitation is a crucial interaction for C. polylophus, future conservation programs should include the protection of plant communities.

scholarly journals Quality and Yield of Forage as Affected by Chemical Removal of Blue Oak (Quercus douglasii)

1964 ◽  
Vol 17 (3) ◽  
pp. 142 ◽  
Author(s):  
Alfred H. Murphy ◽  
Beecher Crampton
Keyword(s):  
Quercus Douglasii ◽  
Blue Oak

Restoration demography and genetics of plants: when is a translocation successful?

2008 ◽  
Vol 56 (3) ◽  
pp. 187 ◽  
Author(s):  
Eric S. Menges
Keyword(s):  
Seedling Recruitment ◽  
Demographic Data ◽  
Ecological Factors ◽  
Basic Knowledge ◽  
Vital Rates ◽  
Evolutionary Potential ◽  
Ecological Processes ◽  
Factors Affecting ◽  
Data Collection And Analysis ◽  
Key Species

Restorations are complex, often involving restoring ecological processes, vegetation structure, and species’ populations. One component of restorations is translocation of key species. Translocations (introductions, reintroductions, augmentations) are often necessary to recover species diversity and install key species. In this review, I consider the ways translocations have been evaluated at various stages during the process of restoration. Vital rates (survival, growth, fecundity) of propagules (seeds, transplants) are commonly used to evaluate initial success. Transplants usually provide greater initial success than do sown seeds. Beyond initial rates, completion of the life cycle through flowering, fruiting, dispersal and subsequent seedling recruitment is a key benchmark. Modelling population viability of translocated populations is a logical next step and can bring in many powerful inferential tools. Of factors affecting the success of translocations, genetic issues are paramount, as restorationists need to consider inbreeding depression, reproductive viability, local adaptation, and evolutionary potential of translocated populations. The success of translocations is also clearly context-dependent, with herbivory, disturbance, competition and other ecological factors important. Future translocations need to make better use of comparisons with reference populations, a long-term perspective on success and an experimental framework that can provide both practical and basic knowledge. Demographic data collection and analysis in restorations has great potential to elucidate causes of translocation failure and improve the prognosis of future restorations.

Factors Affecting Seed Germination of Perennial Wall Rocket (Diplotaxis tenuifolia) in Southern Australia

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 481-485 ◽  
Author(s):  
Samuel G. L. Kleemann ◽  
Bhagirath S. Chauhan ◽  
Gurjeet S. Gill
Keyword(s):  
Osmotic Potential ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
South Australia ◽  
Soil Surface ◽  
Burial Depth ◽  
Optimal Conditions ◽  
Factors Affecting ◽  
Depth Of Burial ◽  
Osmotic Potentials

Germination response of perennial wall rocket to temperature, light, osmotic potential, and depth of burial emergence was evaluated under controlled environmental conditions. The effect of seed burial depth on seedling recruitment in the field was also investigated at Roseworthy, South Australia. Under optimal conditions (30 C, light/dark) germination of perennial wall rocket was rapid, with 90% of seeds germinating within 48 h of imbibition. Germination was reduced (20%) at lower, suboptimal temperatures (10 to 20 C) when seeds of perennial wall rocket were exposed to light. Germination declined with increasing osmotic potential and was completely inhibited at osmotic potentials of −1.5 MPa. Perennial wall rocket emergence was greatest from seeds placed on the soil surface, but some seedlings (< 10%) emerged from a depth of 0.5 to 2 cm. Under both field and growth-cabinet conditions, the greatest seedling emergence of perennial wall rocket occurred from seed present on the soil surface; however, the level of absolute recruitment from the seed bank was much lower (< 5%). Information gained from this study will further improve our understanding of the germination behavior of perennial wall rocket and contribute to developing sustainable strategies for its control.

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