scholarly journals Measuring habitat quality for waterbirds: a review

2021 ◽  
Author(s):  
Rowan Mott ◽  
Thomas Prowse ◽  
Micha Jackson ◽  
Daniel Rogers ◽  
Jody O'Connor ◽  
...  
Keyword(s):  
Habitat Quality ◽  
Body Condition ◽  
Behavioural Change ◽  
High Mobility ◽  
Time Frame ◽  
Habitat Characteristics ◽  
Stochastic Variation ◽  
Measured Variable ◽  
Demographic Rates ◽  
Multiple Variables

Quantifying habitat quality is dependent on measuring a site’s relative contribution to population growth rate. This is challenging for studies of waterbirds, whose high mobility can decouple demographic rates from local habitat conditions and make sustained monitoring of individuals near-impossible. To overcome these challenges, biologists have used many direct and indirect proxies of waterbird habitat quality. However, consensus on what methods are most appropriate for a given scenario is lacking. We undertook a structured literature review of the methods used to quantify waterbird habitat quality, and provide a synthesis of the context-dependent strengths and limitations of those methods. Our structured search of the Web of Science database returned a sample of 398 studies, upon which our review was based. The reviewed studies assessed habitat quality by either measuring habitat attributes (e.g., food abundance, water quality, vegetation structure), or measuring attributes of the waterbirds themselves (e.g., demographic parameters, body condition, behaviour, distribution). Measuring habitat attributes, although they are only indirectly related to demographic rates, has the advantage of being unaffected by waterbird behavioural stochasticity. Conversely, waterbird-derived measures (e.g., body condition, peck rates) may be more directly related to demographic rates than habitat variables, but may be subject to greater stochastic variation (e.g., behavioural change due to presence of conspecifics). Therefore, caution is needed to ensure that the measured variable does influence waterbird demographic rates. This assumption was usually based on ecological theory rather than empirical evidence. Our review highlighted that there is no single best, universally applicable method to quantify waterbird habitat quality. Individual project specifics (e.g., time frame, spatial scale, funding) will influence the choice of variables measured. Where possible, practitioners should measure variables most directly related to demographic rates. Generally, measuring multiple variables yields a better chance of accurately capturing the relationship between habitat characteristics and demographic rates.

Influence of habitat composition on nestling body condition and breeding success in European Pied Flycatchers (Ficedula hypoleuca)

2019 ◽  
Vol 12 (2) ◽  
pp. 67-72 ◽  
Author(s):  
Michał Glądalski ◽  
Iwona Cyżewska ◽  
Mirosława Bańbura ◽  
Adam Kaliński ◽  
Marcin Markowski ◽  
...  
Keyword(s):  
Habitat Quality ◽  
Body Condition ◽  
Breeding Success ◽  
Deciduous Forest ◽  
Haemoglobin Concentration ◽  
Ficedula Hypoleuca ◽  
Habitat Characteristics ◽  
Nest Sites ◽  
Preferred Habitat ◽  
Crucial Component

The vegetation structure surrounding nest sites is a crucial component of habitat quality and may have large effects on avian breeding performance. Habitat quality reflects the extent to which the environmental characteristics of an area correspond to the preferred habitat characteristics of the species. The concentration of haemoglobin is considered a simple biochemical indicator of nestling body condition. We present results concerning the effects of variation in habitat characteristics on the concentration of haemoglobin in the blood of 14-day-old nestlings and breeding success of European Pied Flycatchers ( Ficedula hypoleuca) in a mature mixed deciduous forest in central Poland. The haemoglobin concentration of nestlings was higher when there were more native oaks and deciduous, native trees on the territory. Breeding success was reduced by the number of alien oak (the Red Oak, Quercus rubra) and other alien deciduous trees, but increased by the number of native oaks in the territory. This study was conducted on only one site so further research is needed to examine the broader applicability of our results. Our data support the idea that haemoglobin concentration may serve as a simple indicator of body condition in nestlings and is useful in field ecophysiology studies of European Pied Flycatchers.

scholarly journals Expected Effects of Correlated Habitat Variables on Habitat Quality and Bird Distribution

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 505-515 ◽  
Author(s):  
William B. Kristan
Keyword(s):  
Simple Model ◽  
Habitat Quality ◽  
Growth Rates ◽  
Complete Information ◽  
Habitat Choice ◽  
Ecological Trap ◽  
Demographic Rates ◽  
Multiple Variables ◽  
Population Demographic ◽  
Habitat Variables

Abstract Abstract. Habitats are composed of multiple variables, each of which may affect one or more population demographic rates. The patterns of correlation among habitat variables can introduce correlations among demographic rates, even if any single habitat variable affects only a single demographic rate and is independent of others. I present a simple model in which habitat is composed of two continuous habitat variables, one of which affects fecundity but not survival, and the other of which affects survival but not fecundity, such that correlations between survival and fecundity are due exclusively to correlations between the habitat variables. When individuals are able to select habitat with complete information about habitat quality, habitat selection always leads to higher growth rates at small population sizes. With complete information about habitat quality, patterns of distribution and population growth rates are strongly affected by the correlation between habitat variables. In contrast, when individuals have information about only fecundity or survival but not both, distributions become insensitive to correlations among habitat variables, which can lead to an ecological trap. This simple model demonstrates why explicitly distinguishing between habitat choices and the consequences of choices will be necessary if the complex interplay between habitat structure, habitat choice, and habitat quality is to be fully understood.

scholarly journals Variation among colonies in breeding success and population trajectories of wandering albatrosses Diomedea exulans at South Georgia

Polar Biology ◽  
2021 ◽  
Author(s):  
Carola Rackete ◽  
Sally Poncet ◽  
Stephanie D. Good ◽  
Richard A. Phillips ◽  
Ken Passfield ◽  
...  
Keyword(s):  
Body Condition ◽  
Breeding Success ◽  
Population Trends ◽  
Contributing Factors ◽  
South Georgia ◽  
Vortex Model ◽  
Demographic Rates ◽  
Diomedea Exulans ◽  
Adult Body ◽  
Provisioning Rate

AbstractThe wandering albatross, Diomedea exulans, is a globally threatened species breeding at a number of sites within the Southern Ocean. Across the South Georgia archipelago, there are differences in population trends even at closely located colonies. Between 1999 and 2018 the largest colony, at Bird Island, declined at 3.01% per annum, while in the Bay of Isles, the decline was 1.44% per annum. Using mean demographic rates from a 31-year study at Bird Island and an 11-year study of breeding success at Prion Island in the Bay of Isles in a VORTEX model, we show that differences in breeding success do not fully explain observed differences in population trends. Other potential contributing factors are differential use of foraging areas, with possible knock-on effects on adult body condition, provisioning rate and breeding success, or on bycatch rates of adults or immatures.

Seasonal Pattern of Androgen Secretion in the Male Platypus, Ornithorhynchus anatinus, in the Upper Barnard River, New South Wales.

1998 ◽  
Vol 20 (2) ◽  
pp. 215
Author(s):  
N.P. New ◽  
J.M. Jakubowski ◽  
G.M. Stone ◽  
R.C. Jones
Keyword(s):  
Body Condition ◽  
Peripheral Blood ◽  
New South ◽  
Seasonal Pattern ◽  
New South Wales ◽  
Time Frame ◽  
Volume Index ◽  
South Wales ◽  
Peripheral Blood Plasma ◽  
Androgen Secretion

The seasonal pattern of androgen secretion in free-ranging male platypuses was determined in samples of peripheral blood plasma and rectal contents collected between February and November 1996, from animals captured in the Upper Barnard River, New South Wales. Cortisol concentrations in peripheral blood were also measured and seasonal changes in body condition were assessed. Androgen concentrations in samples from the different sources all followed a distinctly seasonal pattern, being low from February to June, rising in July to reach the highest values in August before reducing to lower values by September. The high concentrations occurred within a relatively narrow time frame and appeared to be well synchronised among individuals. Within animal comparisons showed that androgen concentrations in excreta were highly correlated with values for blood. Cortisol concentrations were higher in July and August than other months. Males lost body condition during this period (as indicated by changes in the Tail Volume Index) and it is suggested that they were under increased stress at this time due to rivalry between males around the mating season.

scholarly journals HMGB-1 as a Novel Predictor of Disease Severity and Prognosis in Patients with Hemorrhagic Fever with Renal Syndrome

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Hong Du ◽  
Jing Li ◽  
Haitao Yu ◽  
Jianqi Lian ◽  
Ye Zhang ◽  
...  
Keyword(s):  
Disease Severity ◽  
Statistical Significance ◽  
White Blood Cells ◽  
High Mobility ◽  
Hemorrhagic Fever ◽  
Time Frame ◽  
Predictive Capacity ◽  
Predicting Outcome ◽  
Severity Of The Disease ◽  
Better Than

Objective. To examine the predictive capacity of the high mobility group box protein-1 (HMGB-1) for disease severity and prognosis of hemorrhagic fever with renal syndrome (HFRS).Methods. One hundred and five HFRS patients and 28 controls were studied. The concentrations of HMGB-1 in the blood were measured with a commercially available ELISA. The levels of white blood cells (WBC), platelets (PLT), hematocrit (HCT), albumin (ALB), blood urea nitrogen (BUN), serum creatinine (Scr), and uric acid (UA) were routinely tested in the same time frame.Results. The levels of HMGB-1 increased with the severity of the disease (P<0.001). HMGB-1 was positively correlated with WBC and BUN and negatively correlated with PLT, ALB, and UA (P<0.001). HMGB-1 showed statistical significance for predicting prognosis (AUC = 0.800,P<0.001). The sensitivity and specificity of HMGB-1, WBC, PLT, and ALB used in combination for predicting outcome were better than those of single analyses (AUC = 0.892,P<0.001).Conclusions. HMGB-1 can be considered a novel biomarker for severity and outcome in patients with HFRS. The use of HMGB-1, WBC, PLT, and ALB in combination to predict the outcome in patients with HFRS exhibited an acceptable level of diagnostic capability.

scholarly journals Thymomodulin in association with antifungal drugs in the therapy of cats with disseminated cutaneous sporotrichosis: a prospective study

2021 ◽  
Vol 51 (6) ◽  
Author(s):  
Gustavo Soares Forlani ◽  
Risciela Salardi Alves de Brito ◽  
Jéssica Paola Salame ◽  
Angelita Reis Gomes ◽  
Fábio Raphael Pascoti Bruhn ◽  
...  
Keyword(s):  
Survival Rate ◽  
Body Condition ◽  
Body Condition Score ◽  
Clinical Signs ◽  
Time Frame ◽  
Antifungal Drugs ◽  
Treatment Modalities ◽  
Condition Score ◽  
Group 2 ◽  
A Prospective Study

ABSTRACT: Feline sporotrichosis is a relevant mycose in veterinary medicine due to its severity and zoonotic potential and the fact that it can be difficult to treat. The immune status of the animal exerts influence on the prognosis of the disease and determines its clinical outcome. This study evaluated the efficacy of the immunomodulatory thymomodulin as an adjunct to antifungal therapy in cats with disseminated sporotrichosis; thymomodulin was used in association with itraconazole (ITL) and potassium iodide (KI) to treat this fungal disease in the feline patient. Thirty-one cats (n=31) diagnosed with disseminated cutaneous sporotrichosis were divided into two groups as follows: Group 1 (G1) (n=16), which included those animals that were treated with thymomodulin in association with ITL and KI, and Group 2 (G2) (n=15) which had pacientsthat received ITL and KI only. The response to different treatment modalities was assessed, considering the survival rate, time frame for the lesions to respond to therapy, and clinical improvement or deterioration according to a body condition score system. Animals from G1 had a survival rate of nearly 100% (93.6%) that was approximately twice higher than the survival rate of those animals from G2 (53%). Moreover, patients from G1 had a significantly better prognosis, improved body condition, and shorter time for remission of the extra cutaneous clinical signs (p<0.02). Our findings showed that the association of thymomodulin with ITL and KI improves the prognosis of cats with disseminated cutaneous sporotrichosis.

scholarly journals Measuring Habitat Quality: A Review

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 489-504 ◽  
Author(s):  
Matthew D. Johnson
Keyword(s):  
Habitat Selection ◽  
Habitat Quality ◽  
Body Condition ◽  
Ecological Factors ◽  
Demographic Variables ◽  
Natural Conditions ◽  
Field Methods ◽  
Advantages And Disadvantages ◽  
New Methods ◽  
Quality Measurements

Abstract Abstract. Understanding habitat quality for birds is crucial for ecologists and managers, but few papers have explored the advantages and disadvantages of different ways to measure it. In this review I clarify terminology and distinguish habitat quality from related terms, differentiate habitat quality at the levels of individual birds and populations, and describe different field methods for measuring habitat quality. As much as feasible, biologists concerned with habitat quality should emphasize demographic variables while recognizing that reproduction, survival, and abundance may not all be positively correlated. The distribution of birds can also reveal habitat quality (e.g., through patterns of habitat selection), but researchers should first investigate how closely their subjects follow ideal distributions because numerous ecological factors can lead birds to select poor and avoid rich habitats. Measures of body condition can provide convenient measures of habitat quality, but to be useful they must be a consequence, rather than a cause, of habitat selection. Habitat ecologists should use caution before relying on shortcuts from more labor-intensive demographic work. To increase the reliability of our habitat quality measurements, we should work to develop new methods to assess critical assumptions of nondemographic indicators, such as whether birds follow ideal distributions under natural conditions and whether spatial variation in body condition manifests in differential fitness.

scholarly journals Telomere length covaries with age across an elevational gradient in a Mediterranean lizard

2019 ◽  
Author(s):  
Pablo Burraco ◽  
Mar Comas ◽  
Senda Reguera ◽  
Francisco Javier Zamora-Camacho ◽  
Gregorio Moreno-Rueda
Keyword(s):  
Life History ◽  
Body Size ◽  
Telomere Length ◽  
Body Condition ◽  
Life History Traits ◽  
Elevational Gradient ◽  
Habitat Characteristics ◽  
Tail Autotomy ◽  
Non Linear

AbstractThe timing of organisms’ senescence is developmentally programmed but also shaped by the interaction between environmental inputs and life-history traits. In ectotherms, ageing dynamics are still poorly understood despite their particularities concerning thermoregulation, regeneration capacity, or growth trajectory. Here, we investigate the role of life-history traits such as age, sex, body size, body condition, and tail autotomy (i.e self-amputation) in shaping telomere length of six populations of the Algerian sand lizard (Psammodromus algirus) distributed across an elevational gradient from 300 to 2500 meters above the sea level. Additionally, we show in a review table the available information on reptiles’ telomere length. We found that telomeres elongated with lizards’ age. We also observed that body size and age class showed a positive relationship, suggesting that cell replication did not shorten lizards’ telomeres by itself. Elevation affected telomere length in a non-linear way, a pattern that mirrored the variation in age structure across elevation. Telomere length was unaffected by tail autotomy, and was sex-independent, but positively correlated with body condition. Our results show that telomeres elongate throughout the first four years of lizards’ lifetime, a process that stress the role of telomerase in maintaining ectothermic telomeres, and, likely, in extending lifespan in organisms with indeterminate growth. Regarding the non-linear impact that elevation had on telomere length of lizards, our results suggest that habitat (mainly temperature) and organisms’ condition might play a key role in regulation ageing rate. Our findings emphasize the relevance of understanding species’ life histories (e.g. age and body condition) and habitat characteristics for fully disentangling the causes and consequences of lifespan trajectory.

scholarly journals Climate Effects on Prey Vulnerability Modify Expectations of Predator Responses to Short- and Long-Term Climate Fluctuations

2021 ◽  
Vol 8 ◽  
Author(s):  
Aïssa Morin ◽  
Simon Chamaillé-Jammes ◽  
Marion Valeix
Keyword(s):  
Body Condition ◽  
Species Interactions ◽  
Species Traits ◽  
Habitat Characteristics ◽  
Prey Abundance ◽  
Predator Prey ◽  
Climate Fluctuations ◽  
Prey Vulnerability ◽  
Induced Changes

Climate changes affect the distribution and abundance of organisms, often via changes in species interactions. Most animals experience predation, and a number of models have investigated how climate fluctuations can influence predator–prey dynamics by affecting prey abundance through changes in resource availability. However, field studies have shown that prey vulnerability is a key feature determining the outcome of predator–prey interactions, which also varies with climatic conditions, via changes in prey body condition or in habitat characteristics (e.g. vegetation cover). In this theoretical work, we explore, with large mammals of African savannas in mind, how the interplay between climate-induced changes in prey abundance and climate-induced changes in prey vulnerability affects the immediate and long-term responses of predator populations. We account for prey body condition and habitat effects on prey vulnerability to predation. We show that predictions on how predator abundance responds to climate fluctuations differ depending on how climate influences prey vulnerability (habitat characteristics vs. prey body condition). We discuss how species traits influence the relative importance of the different sources of vulnerability. For example, our results suggest that populations of cursorial predators (such as spotted hyaenas) are expected to fare better than populations of ambush predators (such as African lions) in African ecosystems that will be characterised by an aridification. This study highlights the importance of understanding, and accounting for, the vulnerability factors associated to a given predator–prey pair, and improves our comprehension of predator–prey relationships in a changing climate.

Stability of optimal harvest regime under stochastic variation in prawn demographic rates and fishing strategies

2003 ◽  
Vol 54 (5) ◽  
pp. 635 ◽  
Author(s):  
Jason E. Tanner
Keyword(s):  
Stochastic Models ◽  
Natural Mortality ◽  
Population Parameters ◽  
Stochastic Variation ◽  
Juvenile Mortality ◽  
Demographic Rates ◽  
Fishing Strategies ◽  
Optimal Harvest ◽  
Random Variation

Although mathematical models are frequently used to assist in the management of fisheries, it is often assumed that a deterministic approximation to reality is sufficient to give reliable results. Many of the processes being modelled, however, can have a substantial stochastic component, and management often needs to be conservative to allow for this stochasticity. In the present investigation, it was found that adding stochasticity to the parameters of a model describing a prawn fishery had little effect on the optimal harvest regime. In both the deterministic and stochastic models the optimal harvest regime involved fishing a small proportion of the habitat very intensively. In particular, random variation in the fishing strategy had almost no effect on long-term harvest rates, although random variation in population parameters could increase the catch. Variation in natural mortality and fecundity influenced harvest rates under any particular fishing strategy more than variation in other parameters. It is likely that these results were obtained because density-dependent juvenile mortality damped out fluctuations in population size, and the targeting of age 2+ animals by the fishery meant that all animals had a chance to spawn before being exposed to harvesting.

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