What Induces Central Australian Arid Zone Trees and Shrubs to Flower and Fruit?

1993 ◽  
Vol 41 (3) ◽  
pp. 307 ◽  
Author(s):  
MH Friedel ◽  
DJ Nelson ◽  
AD Sparrow ◽  
JE Kinloch ◽  
JR Maconochie
Keyword(s):  
Regression Models ◽  
Arid Zone ◽  
Late Summer ◽  
Maximum Temperature ◽  
Data Sets ◽  
Animal Populations ◽  
Time Periods ◽  
Trees And Shrubs ◽  
Term Data

We developed two sets of regression models for flowering and fruiting of arid zone trees and shrubs, based on (i) rainfall in the current and preceding seasons and (ii) soil moisture lagged over varying time periods combined with mean maximum temperature and daylength in the month prior to phenological observations. Using up to 4 years of flowering and fruiting records, we found that both approaches identified responses matching those reported in two other long-term data sets or in the literature, for some species but not for all. The second approach appeared to provide better correlations than the first but we were unable to predict flowering and fruiting effectively. Flowering and fruiting of central Australian trees and shrubs were least in late summer, creating potential limitations on animal populations dependent on them for food. With better predictive capabilities, there is some scope for managing the trees and shrubs for particular purposes. However, very long-term phenological records are needed to improve predictions.

Habitat change at a multi-species goose breeding area on Southampton Island, Nunavut, Canada, 1979–2010

2020 ◽  
Vol 6 (2) ◽  
pp. 95-113
Author(s):  
Kenneth F. Abraham ◽  
Christopher M. Sharp ◽  
Peter M. Kotanen
Keyword(s):  
Late Summer ◽  
Data Sets ◽  
Lesser Snow Geese ◽  
Rock Cover ◽  
East Bay ◽  
Spring Arrival ◽  
Puccinellia Phryganodes ◽  
Cackling Geese ◽  
Term Data

Foraging by hyperabundant Arctic-nesting geese has significant impacts on vegetation of Arctic and subarctic coastal lowlands, but long-term data sets documenting these changes are rare. We undertook intensive surveys of plant communities at East Bay and South Bay, Southampton Island, Nunavut, Canada, in July 2010. Lesser Snow Geese, Ross’s Geese, Cackling Geese, and Brant nest and rear young at these sites; the first three have experienced up to 10-fold increases since the 1970s. At East Bay, we found significant declines in graminoids over the 31-year span, as well as significant declines in lichen and willow cover, and significant increases in rock cover. Transect data indicated graminoids were present at only 15%–36% of points at East Bay, whereas at South Bay, graminoids were present at 28%–90% of points. Moss was more prominent in transects at South Bay than at East Bay (40%–85% vs. 19%–42%), but quadrat data indicated much more of the moss cover at South Bay apparently was dead than at East Bay. Puccinellia phryganodes (Trin.) Scribn. & Merr. exceeded 1% in only two transects. Our data demonstrate a striking decline of preferred forage species and increases in non-forage cover, consistent with the hypothesis that changes resulted from persistent long-term foraging by the four species of breeding geese between spring arrival and late summer departure.

Trophic Level Relationships in Pelagic Food Webs: Comparisons Derived from Long-Term Data Sets for Oneida Lake, New York (USA), and Lake St. George, Ontario (Canada)

1992 ◽  
Vol 49 (8) ◽  
pp. 1588-1596 ◽  
Author(s):  
Donald J. McQueen ◽  
Edward L. Mills ◽  
John L. Forney ◽  
Mark R. S. Johannes ◽  
John R. Post
Keyword(s):  
New York ◽  
Total Phosphorus ◽  
Trophic Level ◽  
Data Sets ◽  
Phytoplankton Abundance ◽  
Data Set ◽  
Oneida Lake ◽  
Pelagic Food Webs ◽  
Term Data

We used standardized methods to analyze a 14-yr data set from Oneida Lake and a 10-yr data set from Lake St. George. We estimated mean summer concentrations of several trophic level indicators including piscivores, planktivores, zooplankton, phytoplankton, and total phosphorus, and we then investigated the relationships between these variables. Both data sets yielded similar long-term and short-term trends. The long-term mean annual trends were that (1) the relationships between concentrations of planktivores and zooplankton (including daphnids) were always negative, (2) the relationships between concentrations of zooplankton and various measures of phytoplankton abundance were unpredictable and never statistically significant, and (3) the relationships between total phosphorus and various measures of phytoplankton abundance were always positive. Over short periods, the data from both lakes showed periodic, strong top-down relationships between concentrations of zooplankton (especially large Daphnia) and chlorophyll a, but these events were unpredictable and were seldom related to piscivore abundance.

scholarly journals Survivable hypothermia or torpor in a wild-living rat: rare insights broaden our understanding of endothermic physiology

2021 ◽  
Author(s):  
Julia Nowack ◽  
Christopher Turbill
Keyword(s):  
Body Temperature ◽  
Data Sets ◽  
Valuable Insight ◽  
Limited Capacity ◽  
Probability Of Survival ◽  
Reduced Body ◽  
Rattus Fuscipes ◽  
Evolutionary Pathways ◽  
Term Data

AbstractMaintaining a high and stable body temperature as observed in endothermic mammals and birds is energetically costly. Thus, it is not surprising that we discover more and more heterothermic species that can reduce their energetic needs during energetic bottlenecks through the use of torpor. However, not all heterothermic animals use torpor on a regular basis. Torpor may also be important to an individual’s probability of survival, and hence fitness, when used infrequently. We here report the observation of a single, ~ 5.5 h long hypothermic bout with a decrease in body temperature by 12 °C in the native Australian bush rat (Rattus fuscipes). Our data suggest that bush rats are able to rewarm from a body temperature of 24 °C, albeit with a rewarming rate lower than that expected on the basis of their body mass. Heterothermy, i.e. the ability to withstand and overcome periods of reduced body temperature, is assumed to be an evolutionarily ancestral (plesiomorphic) trait. We thus argue that such rare hypothermic events in species that otherwise appear to be strictly homeothermic could be heterothermic rudiments, i.e. a less derived form of torpor with limited capacity for rewarming. Importantly, observations of rare and extreme thermoregulatory responses by wild animals are more likely to be discovered with long-term data sets and may not only provide valuable insight about the physiological capability of a population, but can also help us to understand the constraints and evolutionary pathways of different phenologies.

Changes Over Time

2018 ◽  
pp. 283-305 ◽  
Author(s):  
Peter A. Gell ◽  
Marie-Elodie Perga ◽  
C. Max Finlayson
Keyword(s):  
Data Sets ◽  
Lake Ecosystems ◽  
Wetland Ecosystems ◽  
Sediment Layers ◽  
Time Frames ◽  
Changes Over Time ◽  
The Impact ◽  
Term Monitoring ◽  
Term Data

Freshwater systems are continuously shaped by cyclical and directional forces of change, whether they be natural or anthropogenic. Beyond gradual transitions disturbances can reset their internal dynamics generating an abrupt ecological shift. Long-term data sets of gradual or abrupt change can be accessed by exhuming the physical, chemical, and biological remains archived in the sediment layers within lakes and wetlands. Long-term monitoring programmes offer more detailed evidence, usually over shorter time frames. In combination these records attest to the response of wetlands to climate and the impact of industrialised people. Humans have modified lake ecosystems for millennia and the condition of many wetland ecosystems have changed such that they are now regarded as novel. Long-term records provide targets for wetland restoration and can identify the main drivers of degradation. Identification of the character of modern Ramsar wetlands may be enhanced by reference to records of past state.

scholarly journals An Updated Model Providing Long-Term Data Sets of Energetic Electron Precipitation, Including Zonal Dependence

2018 ◽  
Vol 123 (17) ◽  
pp. 9891-9915 ◽  
Author(s):  
M. van de Kamp ◽  
C. J. Rodger ◽  
A. Seppälä ◽  
M. A. Clilverd ◽  
P. T. Verronen
Keyword(s):  
Energetic Electron ◽  
Electron Precipitation ◽  
Data Sets ◽  
Term Data

Calibration Of Long Term Data Sets From Operational Satellites Using The Space Shuttle

1988 ◽  
Author(s):  
Ernest Hilsenrath ◽  
Donald Williams ◽  
John Frederick
Keyword(s):  
Space Shuttle ◽  
Data Sets ◽  
Term Data

Erratum to “Nutrient chemistry of the Ob' and Yenisey Rivers, Siberia: results from June 2000 expedition and evaluation of long-term data sets” [Mar. Chem. 75 (3) (2001) 219–227]

2001 ◽  
Vol 76 (1-2) ◽  
pp. 135 ◽  
Author(s):  
R.M Holmes ◽  
B.J Peterson ◽  
A.V Zhulidov ◽  
V.V Gordeev ◽  
P.N Makkaveev ◽  
...  
Keyword(s):  
Data Sets ◽  
Nutrient Chemistry ◽  
Term Data

PCR for Derivation of Parameter Dependencies, Thermo-Mechanical Norris-Landzberg Acceleration Factors, Goldmann Fatigue Constants for Leadfree Electronics

2009 ◽  
Author(s):  
Pradeep Lall ◽  
Aniket Shirgaokar ◽  
Dineshkumar Arunachalam ◽  
Jeff Suhling ◽  
Mark Strickland ◽  
...  
Keyword(s):  
Test Data ◽  
Thermal Cycle ◽  
Regression Models ◽  
Reliability Prediction ◽  
Maximum Temperature ◽  
Temperature Cycle ◽  
Data Sets ◽  
Accelerated Test ◽  
Bga Packages ◽  
Part Selection

Goldmann Constants and Norris-Landzberg acceleration factors for lead-free solders have been developed based on principal component regression models (PCR) for reliability prediction and part selection of area-array packaging architectures under thermo-mechanical loads. Models have been developed in conjunction with Stepwise Regression Methods for identification of the main effects. Package architectures studied include, BGA packages mounted on copper-core and no-core printed circuit assemblies in harsh environments. The models have been developed based on thermo-mechanical reliability data acquired on copper-core and no-core assemblies in four different thermal cycling conditions. Packages with Sn3Ag0.5Cu solder alloy interconnects have been examined. The models have been developed based on perturbation of accelerated test thermo-mechanical failure data. Data has been gathered on nine different thermal cycle conditions with SAC305 alloys. The thermal cycle conditions differ in temperature range, dwell times, maximum temperature and minimum temperature to enable development of constants needed for the life prediction and assessment of acceleration factors. Goldmann Constants and the Norris-Landzberg acceleration factors have been benchmarked against previously published values. In addition, model predictions have been validated against validation data-sets which have not been used for model development. Convergence of statistical models with experimental data has been demonstrated using a single factor design of experiment study for individual factors including temperature cycle magnitude, relative coefficient of thermal expansion, and diagonal length of the chip. The predicted and measured acceleration factors have also been computed and correlated. Good correlations have been achieved for parameters examined. Previously, the feasibility of using multiple linear regression models for reliability prediction has been demonstrated for flex-substrate BGA packages [Lall 2004, 2005], flip-chip packages [Lall 2005] and ceramic BGA packages [Lall 2007]. The presented methodology is valuable in the development of fatigue damage constants for the application specific accelerated test data-sets and provides a method to develop institutional learning based on prior accelerated test data.

Sign in / Sign up

Export Citation Format

Share Document