Long-term demography of the Northern Goshawk in a variable environment

2017 ◽  
Vol 197 (1) ◽  
pp. 1-40 ◽  
Author(s):  
Richard T. Reynolds ◽  
Jeffrey S. Lambert ◽  
Curtis H. Flather ◽  
Gary C. White ◽  
Benjamin J. Bird ◽  
...  
Keyword(s):  
Variable Environment ◽  
Northern Goshawk

scholarly journals Realistic Choice of Annual Matrices Contracts the Range of λS Estimates

Mathematics ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 2252
Author(s):  
Dmitrii O. Logofet ◽  
Leonid L. Golubyatnikov ◽  
Nina G. Ulanova
Keyword(s):  
Markov Chain ◽  
Local Population ◽  
Quantitative Measure ◽  
Weather Data ◽  
Variable Environment ◽  
Annual Population ◽  
Novel Method ◽  
Stochastic Growth Rate ◽  
Realistic Choice

In matrix population modeling the multi-year monitoring of a population structure results in a set of annual population projection matrices (PPMs), which gives rise to the stochastic growth rate λS, a quantitative measure of long-term population viability. This measure is usually found in the paradigm of population growth in a variable environment. The environment is represented by the set of PPMs, and λS ensues from a long sequence of PPMs chosen at random from the given set. because the known rules of random choice, such as the iid (independent and identically distributed) matrices, are generally artificial, the challenge is to find a more realistic rule. We achieve this with the a following a Markov chain that models, in a certain sense, the real variations in the environment. We develop a novel method to construct the ruling Markov chain from long-term weather data and to simulate, in a Monte Carlo mode, the long sequences of PPMs resulting in the estimates of λS. The stochastic nature of sequences causes the estimates to vary within some range, and we compare the range obtained by the “realistic choice” from 10 PPMs for a local population of a Red-Book species to those using the iid choice. As noted in the title of this paper, this realistic choice contracts the range of λS estimates, thus improving the estimation and confirming the Red-Book status of the species.

scholarly journals Managing for rainfall variability: effect of grazing strategy on cattle production in a dry tropical savanna

2009 ◽  
Vol 49 (2) ◽  
pp. 85 ◽  
Author(s):  
Peter O'Reagain ◽  
John Bushell ◽  
Chris Holloway ◽  
Angela Reid
Keyword(s):  
Southern Oscillation ◽  
Rainfall Variability ◽  
Cattle Production ◽  
Long Term Effects ◽  
Seasonal Forecasts ◽  
Wet Season ◽  
Variable Environment ◽  
Condition Score ◽  
Stocking Rates

Rainfall variability is a challenge to sustainable and profitable cattle production in northern Australia. Strategies recommended to manage for rainfall variability, like light or variable stocking, are not widely adopted. This is due partly to the perception that sustainability and profitability are incompatible. A large, long-term grazing trial was initiated in 1997 in north Queensland, Australia, to test the effect of different grazing strategies on cattle production. These strategies are: (i) constant light stocking (LSR) at long-term carrying capacity (LTCC); (ii) constant heavy stocking (HSR) at twice LTCC; (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC; (iv) variable stocking (VAR), with stocking rates adjusted in May based on available pasture; and (v) a Southern Oscillation Index (SOI) variable strategy, with stocking rates adjusted in November, based on available pasture and SOI seasonal forecasts. Animal performance varied markedly over the 10 years for which data is presented, due to pronounced differences in rainfall and pasture availability. Nonetheless, lighter stocking at or about LTCC consistently gave the best individual liveweight gain (LWG), condition score and skeletal growth; mean LWG per annum was thus highest in the LSR (113 kg), intermediate in the R/Spell (104 kg) and lowest in the HSR (86 kg). Mean LWG was 106 kg in the VAR and 103 kg in the SOI but, in all years, the relative performance of these strategies was dependent upon the stocking rate applied. After 2 years on the trial, steers from lightly stocked strategies were 60–100 kg heavier and received appreciable carcass price premiums at the meatworks compared to those under heavy stocking. In contrast, LWG per unit area was greatest at stocking rates of about twice LTCC; mean LWG/ha was thus greatest in the HSR (21 kg/ha), but this strategy required drought feeding in four of the 10 years and was unsustainable. Although LWG/ha was lower in the LSR (mean 14 kg/ha), or in strategies that reduced stocking rates in dry years like the VAR (mean 18 kg/ha) and SOI (mean 17 kg/ha), these strategies did not require drought feeding and appeared sustainable. The R/Spell strategy (mean 104 kg/ha) was compromised by an ill-timed fire, but also performed satisfactorily. The present results provide important evidence challenging the assumption that sustainable management in a variable environment is unprofitable. Further research is required to fully quantify the long-term effects of these strategies on land condition and profitability and to extrapolate the results to breeder performance at the property level.

scholarly journals Ups and Downs of the Italian Locust (Calliptamus italicus L.) Populations in the Siberian Steppes: On the Horns of Dilemmas

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 746
Author(s):  
Michael Sergeev
Keyword(s):  
West Siberia ◽  
Common Species ◽  
West Siberian Plain ◽  
Pest Species ◽  
Variable Environment ◽  
North East ◽  
The North ◽  
Important Pest ◽  
Ecological Association

The Italian locust is a common species and one of the most important pest in the steppes, semi-deserts, and deserts of Central and Southwestern Asia and also in the Mediterranean Region. The aim of this paper is to discuss some problems arising from studies of eco-geographical distribution and long-term dynamics of this species, especially in the southern part of West Siberia, and their consequences for management of pest species and rare forms. Peculiarities of the Italian locust populations’ distribution and long-term dynamics are discussed for the north-eastern part of the species range (south-eastern West Siberian Plain, North-East and, partly, East Kazakhstan). Notable differences between local populations are revealed. Some issues arising from results of insecticide experimental treatments (mainly effectiveness of barrier applications with different compounds in variable environment) and ecological association between the Italian locust and rare Orthoptera are also discussed. Some suggestions as to requirements for improved monitoring, supervision, control, and forecasting of the Italian locust populations’ distribution and dynamics are also provided.

Long-term farming systems research in the central High Plains

2012 ◽  
Vol 28 (2) ◽  
pp. 183-193 ◽  
Author(s):  
Rajan Ghimire ◽  
Jay B. Norton ◽  
Urszula Norton ◽  
John P. Ritten ◽  
Peter D. Stahl ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Climatic Variability ◽  
Farming Systems ◽  
Integration Scheme ◽  
High Plains ◽  
Variable Environment ◽  
Systems Research ◽  
Central High ◽  
Livestock Systems

AbstractIn recent decades, there has been growing interest among farming and scientific communities toward integrated crop–range–livestock farming because of evidence of increased crop production, soil health, environmental services and resilience to increased climatic variability. This paper reviews studies on existing cropping systems and integrated crop–range–livestock systems across the USA which are relevant in the context of summarizing opportunities and challenges associated with implementing long-term crop–range–livestock systems research in the highly variable environment of the central High Plains. With precipitation ranging from 305 to 484mm and uncertain irrigation water supply, this region is especially vulnerable to changing moisture and temperature patterns. The results of our review indicate that diverse crop rotations, reduced soil disturbance and integrated crop–livestock systems could increase economic returns and agroecosystem resilience. Integrating agricultural system components to acquire unique benefits from small- to medium-sized operations, however, is a challenging task. This is because assessment and identification of suitable farming systems, selection of the most efficient integration scheme, and pinpointing the best management practices are crucial for successful integration of components. Effective integration requires development of evaluation criteria that incorporate the efficiency of approaches under consideration and their interactions. Therefore, establishing the basis for more sustainable farming systems in the central High Plains relies on both long-term agricultural systems research and evaluation of short-term dynamics of individual components.

scholarly journals Local Weather Explains Annual Variation In Northern Goshawk Reproduction In the Northern Great Basin, USA

2021 ◽  
Author(s):  
Allyson B. Bangerter ◽  
Eliana R. Heiser ◽  
Jay D. Carlisle ◽  
Robert A. Miller
Keyword(s):  
Climate Change ◽  
Great Basin ◽  
Prey Availability ◽  
Northern Goshawk ◽  
South Central ◽  
Mean Temperature ◽  
Northern Utah ◽  
Using Data ◽  
Projected Changes

ABSTRACT Weather is thought to influence raptor reproduction through effects on prey availability, condition of adults, and survival of nests and young; however, there are few long-term studies of the effects of weather on raptor reproduction. We investigated the effects of weather on Northern Goshawk (Accipiter gentilis; henceforth goshawk) breeding rate, productivity, and fledging date in south-central Idaho and northern Utah, USA. Using data from 42 territories where we found evidence of breeding attempts in ≥1 yr from 2011–2019, we analyzed breeding rates using 315 territory–season combinations, analyzed productivity for 134 breeding attempts, and analyzed fledging date for 118 breeding attempts. We examined 35 predictor variables from four categories: precipitation, temperature, wind, and snowpack. Of the variables we evaluated, April precipitation, previous year's April–July precipitation, April–May mean temperature, and March–May mean temperature were related to measures of goshawk reproduction. Greater April–July precipitation in the previous year and lower April precipitation in the current year were associated with higher breeding rates. Years with warmer average April–May temperatures were associated with increased goshawk productivity. Years with greater April–July precipitation during the previous year and lower mean March–May temperatures were associated with later fledging dates. Based on these relationships, we considered projected changes in weather in the northern Great Basin over the next 50 yr as a result of climate change (without directly accounting for habitat changes caused by climate change), and predicted that climate change will: (a) have no significant effect on goshawk breeding rate, (b) have a positive effect on goshawk productivity, and (c) cause a shift toward earlier goshawk breeding. Our results indicate that weather is significantly related to goshawk reproduction in the northern Great Basin, and we suggest that the relationship between raptor breeding and weather be further investigated to enable higher resolution predictions of how changes in the climate may influence their populations, particularly changes that may not have been captured by our study.

scholarly journals Managing for rainfall variability: long-term profitability of different grazing strategies in a northern Australian tropical savanna

2011 ◽  
Vol 51 (3) ◽  
pp. 210 ◽  
Author(s):  
Peter O'Reagain ◽  
John Bushell ◽  
Bill Holmes
Keyword(s):  
Sustainable Management ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Seasonal Forecasts ◽  
Variable Environment ◽  
Poor Condition ◽  
Product Value ◽  
Grazing Strategies ◽  
Stocking Rates

Several grazing strategies are recommended to manage sustainably for rainfall variability in northern Australia, but there is little objective data on their profitability relative to less sustainable management systems such as heavy stocking. In 1997, a large cattle grazing trial was initiated in northern Queensland to quantify the relative performance of a range of grazing strategies in a variable climate. These strategies were (i) moderate stocking (MSR) stocked at the calculated long-term carrying capacity (LTCC), (ii) heavy stocking (HSR) at twice LTCC, (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC, (iv) variable stocking (VAR), with stocking rates adjusted in May based on available forage and (v) a southern oscillation index (SOI)-variable strategy, with stocking rates adjusted in November based on available forage and SOI-based seasonal forecasts. Rainfall varied over the 12-year trial period, with sequences of dry and wet years. Gross margins (GM) in the HSR were initially high but collapsed in drier years due to high costs and reduced product value. GMs only recovered in later years with a reduced stocking rate and increased rainfall. The VAR and SOI were also initially very profitable, but GMs plunged as rainfall declined due to reduced animal performance and the sale of poor-condition cattle. This sharp cut in stocking rates nevertheless allowed GMs to recover well in subsequent years. In the MSR, GMs remained relatively constant across most years due to low costs and a higher product value. The R/Spell also performed relatively well despite being compromised by an ill-timed fire, drought and the subsequent sale of poor-condition cattle. Net present value (NPV) after 12 years was highest in the VAR ($11 962/100 ha), followed by the MSR ($11 873/100 ha), the SOI ($11 167/100 ha) and the R/Spell ($10 665/100 ha). NPV was by far the lowest in the HSR ($6930/100 ha). Profitability also varied the most in the HSR, with a negative GM in 6 of the 12 years. Incorporating the costs of natural resource decline would further reinforce the case against heavy stocking. These results challenge the assumption that sustainable management in a variable environment is unprofitable.

A METHOD FOR LONG-TERM MULTIPLE-CHANNEL RECORDING OF OXYGEN CONSUMPTION IN AQUATIC ANIMALS

1993 ◽  
Vol 185 (1) ◽  
pp. 357-365
Author(s):  
T. Nordtug ◽  
A. J. Olsen
Keyword(s):  
Oxygen Consumption ◽  
Environmental Monitoring ◽  
Toxicity Testing ◽  
Variable Environment ◽  
Multiple Channel ◽  
Reasonable Cost ◽  
Routine Basis ◽  
Rate Of Oxygen Consumption ◽  
Maintenance Work

The objective of the present work has been to develop a method for measuring the rate of oxygen consumption on a routine basis during toxicity testing and environmental monitoring. This requires a method that is reliable over long periods and can be used with a minimum of maintenance work in a variable environment. The system should consist of a compact unit easily transported and available at a reasonable cost. Visual updated records of the oxygen consumption should be available at all times.

scholarly journals Multiple concurrent and convergent stages of genome reduction in bacterial symbionts across a stink bug family

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alejandro Otero-Bravo ◽  
Zakee L. Sabree
Keyword(s):  
Genome Reduction ◽  
Feeding Strategies ◽  
Stink Bug ◽  
Stink Bugs ◽  
Free Living ◽  
Variable Environment ◽  
Host Interactions ◽  
History Of ◽  
Living Bacterium

AbstractNutritional symbioses between bacteria and insects are prevalent and diverse, allowing insects to expand their feeding strategies and niches. A common consequence of long-term associations is a considerable reduction in symbiont genome size likely influenced by the radical shift in selective pressures as a result of the less variable environment within the host. While several of these cases can be found across distinct insect species, most examples provide a limited view of a single or few stages of the process of genome reduction. Stink bugs (Pentatomidae) contain inherited gamma-proteobacterial symbionts in a modified organ in their midgut and are an example of a long-term nutritional symbiosis, but multiple cases of new symbiont acquisition throughout the history of the family have been described. We sequenced the genomes of 11 symbionts of stink bugs with sizes that ranged from equal to those of their free-living relatives to less than 20%. Comparative genomics of these and previously sequenced symbionts revealed initial stages of genome reduction including an initial pseudogenization before genome reduction, followed by multiple stages of progressive degeneration of existing metabolic pathways likely to impact host interactions such as cell wall component biosynthesis. Amino acid biosynthesis pathways were retained in a similar manner as in other nutritional symbionts. Stink bug symbionts display convergent genome reduction events showing progressive changes from a free-living bacterium to a host-dependent symbiont. This system can therefore be used to study convergent genome evolution of symbiosis at a scale not previously available.

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