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95 results for “Larrea”
Larrea Seedling Monitoring Study at the Sevilleta National Wildlife Refuge, New Mexico (1999-2018)
The germination rate of creosote (Larrea tridentata) on the Sevilleta appears to be very low. During the early years of the LTER project it was attempted to quantify such germination through the use of seedling plots which were monitored on a bi-annual basis (spring and fall). During the period from 1989 through 1992 there were no creosote seedling that germinated on the monitoring plots. In 1999 a rather sizeable population of small seedlings was observed in one quite localized area in the vicinity of Five Points. This rather large number of individuals in one very limited area raised several questions:1. When did this small community of individuals germinate- the supposition is that they had all germinated at the same time.2. What conditions existed in this particular location which allowed such prolific germination when there was no indication of virtually any other germination in this vicinty.3. The most immediate question was whether these seedlings would survive through the impending La Nina winter, spring and summer as many of the individuals did not appear to be very "healthy." To help answer these questions it was decided to begin a "small" monitoring project. All of the individuals in this small area that appeared to be of the same age were marked with posts, located with GPS, measured (height) and photographed. This initial survey included 78 individuals. The population was resurveyed in August, 2000 and it was discovered that: 1. Many individuals were missed in the initial survey; 2. Most of the individuals (72 of 78) had survived the intervening 9 months; and 3. The average individual growth during this period was 1.4 cm. It is planned that this population will continue to be monitored (probably on an annual basis) to track survival and growth rate of these individuals.
Density-dependent demography of creosote bush (Larrea tridentata) along grass-shrub ecotones.
The encroachment of woody plants into grasslands is a global phenomenon with implications for biodiversity and ecosystem function. Understanding and predicting the pace of expansion and the underlying processes that control it are key challenges in the study and management of woody encroachment. Theory from spatial population biology predicts that the occurrence and speed of population expansion should depend sensitively on the nature of conspecific density dependence. If fitness is maximized at the low-density encroachment edge then shrub expansion should be "pulled" forward. However, encroaching shrubs have been shown to exhibit positive feedbacks, whereby shrub establishment modifies the environment in ways that facilitate further shrub recruitment and survival. In this case there may be a fitness cost to shrubs at low density causing expansion to be "pushed" from behind the leading edge. We studied the spatial dynamics of creosotebush (Larrea tridentata), which has a history of encroachment into Chihuahuan Desert grasslands over the past century. We used demographic data from observational censuses and seedling transplant experiments to test the strength and direction of density dependence in shrub fitness along a gradient of shrub density at the grass-shrub ecotone. We also used seed-drop experiments and wind data to construct a mechanistic seed dispersal kernel, then connected demography and dispersal data within a spatial integral projection model (SIPM) to predict the dynamics of shrub expansion. The SIPM predicted that, contrary to expectations based on potential for positive feedbacks, the shrub encroachment wave is "pulled" by maximum fitness at the low-density front. However, the predicted pace of expansion was strikingly slow (ca. 8 cm/yr), and this prediction was supported by independent re-surveys of the ecotone showing little to no change in spatial extent of shrub cover over 12 years. Encroachment speed was acutely sensitive to seedling recruitment,
Hydraulic Constraints on Two Life History Stages of Larrea tridentata in a Chihuahuan Desert Creosote Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (2002-2003)
Maintaining high rates of water loss during times of high resource availability could allow establishing woody desert perennials to grow quickly by allowing them to take advantage of the fleeting but abundant monsoonal moisture typical of warm deserts like the Chihuahuan. However, a plant cannot endlessly increase water loss in order to grow faster --there are hydraulic constraints on rates of water loss. The hydraulic properties of each particular plant xylem and soil microsite, as well as the AR:AL absorbing root area to transpiring leaf area ratio) interact to set limits on rates of water loss. If transpiration rates become too high, cavitation may limit the ability of the xylem to supply water to the leaves. The main objective of this study was to test two hypotheses on a population of Larrea tridentata at the Sevilleta LTER in central New Mexico (1) do small plants grow faster and use water less conservatively than large, and (2) are there differences in the hydraulic constraints on small and large plants. Measurements were made every six weeks in the spring, summer and fall from April 2002 - August 2003. Field measurements of shoot growth, gas exchange and plant and soil water potentials were made to determine growth rates and water use. Measurements of leaf specific conductance determined the ability of the xylem to supply water to the leaves. Excavation findings were used to estimate (AR:AL). Xylem vulnerability curves and soil texture analysis were used to determine the hydraulic properties of the plant xylem and soil. A model determined where the limiting conductance occurred in the plant-soil continuum.
Larrea tridentata (Zygophyllaceae) - inflorescence - frontal view of flower
Image of Larrea tridentata (Zygophyllaceae) - inflorescence - frontal view of flower
Larrea tridentata (Zygophyllaceae) - inflorescence - whole - unspecified
Image of Larrea tridentata (Zygophyllaceae) - inflorescence - whole - unspecified
Larrea tridentata (Zygophyllaceae) - twig - orientation of petioles
Image of Larrea tridentata (Zygophyllaceae) - twig - orientation of petioles
Larrea tridentata (Zygophyllaceae) - bark - of a small tree or small branch
Image of Larrea tridentata (Zygophyllaceae) - bark - of a small tree or small branch
Larrea tridentata (Zygophyllaceae) - leaf - whole upper surface
Image of Larrea tridentata (Zygophyllaceae) - leaf - whole upper surface
Larrea tridentata (Zygophyllaceae) - whole tree (or vine) - general
Image of Larrea tridentata (Zygophyllaceae) - whole tree (or vine) - general
Larrea tridentata (Zygophyllaceae) - leaf - showing orientation on twig
Image of Larrea tridentata (Zygophyllaceae) - leaf - showing orientation on twig
Larrea tridentata (Zygophyllaceae) - leaf - showing orientation on twig
Image of Larrea tridentata (Zygophyllaceae) - leaf - showing orientation on twig
Larrea tridentata (Zygophyllaceae) - whole tree (or vine) - general
Image of Larrea tridentata (Zygophyllaceae) - whole tree (or vine) - general
Larrea tridentata (Zygophyllaceae) - whole tree (or vine) - general
Image of Larrea tridentata (Zygophyllaceae) - whole tree (or vine) - general
Larrea tridentata (Zygophyllaceae) - fruit - lateral or general close-up
Image of Larrea tridentata (Zygophyllaceae) - fruit - lateral or general close-up
Larrea tridentata (Zygophyllaceae) - fruit - as borne on the plant
Image of Larrea tridentata (Zygophyllaceae) - fruit - as borne on the plant
Figure 1–13. 1–8 in A new genus for Drepanocanthoides larreae (Horn, 1887) and description of a new congeneric Mexican species (Coleoptera: Scarabaeidae: Aphodiinae)
Figure 1–13. 1–8) Hornosus larreae (Horn, 1887) (Florence, Arizona, U.S.A.). 1) Epipharynx. 2–3) Outline of clypeus (male and female). 4) Male right foretibia (dorsal view). 5–6) Habitus (length ideogram and morphological details). 7–8) Aedeagus (dorsal and lateral views). 9–13) Hornosus turnbowi new species (Hwy 58, 8 km E jct 57, Nuevo León, Mexico). 9) Epipharynx. 10–11) Habitus (length ideogram and morphological details). 12–13) Aedeagus (dorsal and lateral views).
FIGURES 1– 4 in Hesperapis rhodocerata: Behavioral Biology, Egg, and Larval Instars, Including Behavioral and Larval Comparisons with H. larreae (Hymenoptera: Melittidae: Dasypodainae)
FIGURES 1– 4. Nests of Hesperapis rhodocerata. 1. Nesting site at 28 mi south of Animas, Hidalgo Co., NM, with most nest entrances among yellow-flowered Heterotheca toward right side of picture when first found in late summer 2010. 2. John S. Ascher excavating first nest in 2010, with Margaret A. Rozen looking on. 3. Female Hesperapis rhodocerata with pollen loads being transported on anterior surface of hind tibiae. 4. Closeup of basitarsus showing dorsal trough of hairs used for flinging sand. 5–9. Sequential stills from slow-motion video showing position of hind legs when flinging sand from nest entrance. For explanation, please read text. [Figs. 1–3 courtesy John S. Ascher]
FIGURES 13–16 in Hesperapis rhodocerata: Behavioral Biology, Egg, and Larval Instars, Including Behavioral and Larval Comparisons with H. larreae (Hymenoptera: Melittidae: Dasypodainae)
FIGURES 13–16. Macrophotographs of cells of Hesperapis larreae collected in 1990 and 1994, preserved in the AMNH, from extreme southern Yavapai Co., AZ, at 8 mi NW of Wickenburg, Maricopa Co. Note smooth inner surface of wall and fine-grained sand lining contrasting with coarse substrate. 13. Fresh cell. 14. Close-up of cell wall, showing fine texture and absence of protruding pebbles. 15. Cells from which postdefecating larvae removed after application of hardening material. 16. Fragment of cell wall from figure 15 showing brownish, smoothly flattened fecal pellets.
FIGURES 23–25 in Hesperapis rhodocerata: Behavioral Biology, Egg, and Larval Instars, Including Behavioral and Larval Comparisons with H. larreae (Hymenoptera: Melittidae: Dasypodainae)
FIGURES 23–25. Diagram of egg of Hesperapis rhodocerata lateral view, anterior end to left. FIGURES 24, 25. Diagrams of second instar of Hesperapis rhodocerata, spicules not shown. 24. Entire larva, lateral view. 25. Abdominal segments 4 and 5, ventral view showing paired tubercles.
FIGURES 26–30 in Hesperapis rhodocerata: Behavioral Biology, Egg, and Larval Instars, Including Behavioral and Larval Comparisons with H. larreae (Hymenoptera: Melittidae: Dasypodainae)
FIGURES 26–30. Diagrams of mature larvae of Hesperapis rhodocerata. 26. Entire postdefecating larva, lateral view. 27. Predefecating larva, lateral view. 28, 29. Head, frontal and lateral views, respectively. FIGURE 30. Diagram of mature larva of Hesperapis larreae, lateral view.
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Allen Brain Atlas
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DANDI Archive for NWB datasets
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International Brain Laboratory public data
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OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.