scholarly journals Effects of supplementary feed for game birds on activity of brown rats Rattus norvegicus on arable farms

2020 ◽  
Author(s):  
Siti Md Saad ◽  
Roy Sanderson ◽  
Peter Robertson ◽  
Mark Lambert
Keyword(s):  
Linear Models ◽  
Camera Traps ◽  
Monitoring Methods ◽  
Mixed Effect ◽  
Factors Affecting ◽  
Game Bird ◽  
Game Birds ◽  
Bird Feeders ◽  
Brown Rat ◽  
Supplementary Feed

Abstract Brown rats are widespread in agroecosystems, but our understanding of factors affecting their activity is incomplete due to cryptic, nocturnal behaviours. Indirect monitoring methods include tracking plates and camera traps. Supplementary feeding of game birds may provide resources for rats away from farm buildings, allowing them to persist in winter when there is little other food available. Developing reliable methods to monitor such populations will facilitate landscape-scale studies of rat populations in farm environments and aid ecologically based approaches for controlling rats on farms. We compared camera traps and tracking plates to monitor brown rat activity near game bird feeders at a mixed farm in Northumberland, UK. Generalized linear models (GLM) were used to compare rat incidence estimated from camera traps and tracking plates. A strong positive relationship was found between the two methods, although tracking plate estimates were less reliable when rat activity was very low. Factors that affected populations of brown rats near game bird feeders were assessed via linear mixed-effect models (LMM) of monthly tracking plate data (October 2017 to September 2018). Populations were highest at the feeders (0 m) compared with further away (10 m, 20 m) and were also higher in periods of cold, wet weather and when more food was available from the feeders. Rodenticide application near feeders did not significantly affect activity, nor did land cover 100 m around each feeder. A highly significant relationship was detected with food supply, suggesting that the use of game bird feeders could potentially have major impacts on rat population dynamics.

scholarly journals Factors affecting canine fecal and parasitic contamination of public green spaces of Buenos Aires city, Argentina, and visitors’ perception of such contamination

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Diana Rubel ◽  
Sergio I Nemirovsky ◽  
Irene Gorosito ◽  
Andrea Servián ◽  
Graciela Garbossa
Keyword(s):  
Green Space ◽  
Linear Models ◽  
Buenos Aires ◽  
Environmental Control ◽  
Fecal Contamination ◽  
Control Measures ◽  
Green Spaces ◽  
Mixed Effect ◽  
Fecal Samples ◽  
Factors Affecting

Abstract Canine fecal contamination in public green areas is difficult to control. Our objectives were to assess: (i) the relationship between fecal contamination in public green spaces of Buenos Aires (Argentina) and the type of green space (boulevard/square/park), considering their area, presence/absence of control measures, and human population density in the surroundings (high or low); (ii) the perception of people of such contamination and (iii) the frequency of parasites in dog feces. In each green space (n = 26), feces were counted in thirty 25-m2 plots randomly located. The opinion survey consisted of asking people (358) what their perception of fecal contamination was, whether it bothered them and whether they thought it was hazardous to the dogs’ or people’ health. Canine fecal samples randomly collected (n = 112) were concentrated and examined microscopically. Mixed-effect generalized linear models were fitted to evaluate the effect of selected variables on fecal contamination. People’s perception of human and canine health risks were assessed by logistic regression. Canine fecal contamination was lower in squares with control measures and in parks with control measures located in densely populated areas, and higher in boulevards located in densely populated areas. The visitor’s perception was that feces were associated with dirtiness (77%) and odor (30.8%). Parasites were detected in 51.8% of fecal samples. Our results confirm that environmental control measures decrease canine fecal contamination of public green spaces, and that more than 65% of the people interviewed do not relate fecal contamination to risks to human/dog health.

scholarly journals Factors affecting presence and relative abundance of the Endangered volcano rabbit Romerolagus diazi, a habitat specialist

Oryx ◽  
2021 ◽  
pp. 1-10
Author(s):  
Felipe Osuna ◽  
Roger Guevara ◽  
Enrique Martínez-Meyer ◽  
Raúl Alcalá ◽  
Alejandro Espinosa de los Monteros
Keyword(s):  
Sierra Nevada ◽  
Relative Abundance ◽  
Linear Models ◽  
Cattle Grazing ◽  
Patch Occupancy ◽  
Factors Affecting ◽  
Rock Cover ◽  
Volcanic Fields ◽  
Mountain Grasslands ◽  
Insight Into

Abstract Habitat specialists are particularly vulnerable to extinction when habitat conditions are altered. Information on the habitat use of such species is thus important because it provides insight into factors that influence distribution and abundance, which is crucial for conservation. Here, we aimed to identify factors that influence the patterns of presence and abundance of the Endangered volcano rabbit Romerolagus diazi, a rare leporid with a patchy distribution. Through exhaustive sampling of its range in the Sierra Chichinautzin and Sierra Nevada volcanic fields, Mexico, and using generalized linear models, we found that the probability of patch occupancy was higher where bunchgrass cover exceeded 75%, rock cover exceeded 5%, no cattle grazing was observed and human settlements were at least 7 km away. Patches with greater relative abundance were those with similar characteristics, but located at elevations > 3,600 m, and with rock cover < 15%. Cattle grazing was identified as a major threat to local populations of the volcano rabbit, particularly in the Sierra Chichinautzin. Because of the significance of bunchgrasses for this species, the protection of the mountain grasslands is required in both volcanic fields.

Using complementary remote detection methods for retrofitted eco-passages: a case study for monitoring individual koalas in south-east Queensland

2016 ◽  
Vol 43 (5) ◽  
pp. 369 ◽  
Author(s):  
C. E. Dexter ◽  
R. G. Appleby ◽  
J. P. Edgar ◽  
J. Scott ◽  
D. N. Jones
Keyword(s):  
Road Construction ◽  
Primary Objective ◽  
Correlated Data ◽  
Camera Traps ◽  
Detection Methods ◽  
Urban Landscapes ◽  
Monitoring Methods ◽  
Monitoring Method ◽  
Phascolarctos Cinereus ◽  
The Individual

Context Vehicle-strike has been identified as a key threatening process for koala (Phascolarctos cinereus) survival and persistence in Australia. Roads and traffic act as barriers to koala movement and can impact dispersal and metapopulation dynamics. Given the high cost of wildlife mitigation structures such as purpose-built fauna-specific underpasses or overpasses (eco-passages), road construction and management agencies are constantly seeking cost-effective strategies that facilitate safe passage for fauna across roads. Here we report on an array of detection methods trialled to verify use of retrofitted road infrastructure (existing water culverts or bridge underpasses) by individual koalas in fragmented urban landscapes in south-east Queensland. Aims The study examined whether the retrofitting of existing road structures at six sites facilitated safe passage for koalas across roads. Our primary objective was to record utilisation of retrofitted infrastructure at the level of the individual. Methods We used a combination of existing monitoring methods such as GPS/VHF collars, camera traps, sand plots, and RFID tags, along with a newly developed animal-borne wireless identification (WID) tag and datalogging system, specifically designed for this project, to realise the study aims. Key results We were able to verify 130 crossings by koalas involving a retrofitted structure or a road surface over a 30-month period by using correlated data from complementary methods. We noted that crossings were generally uncommon and mostly undertaken by only a subset of our tagged individuals at each site (21% overall). Conclusions An important element of this study was that crossing events could be accurately determined at the level of the individual. This allowed for detailed assessment of eco-passage usage, rather than the more usual approach of simply recording species’ presence. Implications This study underscores the value of identifying the constraints of each individual monitoring method in relation to site conditions. It also highlights the benefits of contingency planning to limit data loss (i.e. using more than one method to collect data). We suggest an approach that uses complementary monitoring methods has significant advantages for researchers, particularly with reference to improving understanding of whether eco-passages are meeting their prescribed conservation goals.

scholarly journals The Impacts of Flowering Time and Tillering on Grain Yield of Sorghum Hybrids across Diverse Environments

2019 ◽  
Author(s):  
Xuemin Wang ◽  
Colleen Hunt ◽  
Alan Cruickshank ◽  
Emma Mace ◽  
Graeme Hammer ◽  
...  
Keyword(s):  
Grain Yield ◽  
Flowering Time ◽  
Genetic Background ◽  
Linear Models ◽  
Genetic Correlations ◽  
Environment Interaction ◽  
Canopy Development ◽  
Factors Affecting ◽  
Sorghum Production ◽  
Relationship Of

Sorghum in Australia is grown in water-limited environments of varying extent, generating substantial genotype &times; environment interaction (GEI). Much of the yield variation and GEI results from variations in flowering time and tillering through their effects on canopy development. The confounding effects of flowering and tillering complicate the interpretation of breeding trials. In this study, we evaluated the impacts of both flowering time (DTF) and tillering capacity (FTN) on yield of 1741 unique test hybrids derived from three common female testers in 21 yield testing trials (48 tester/trial combinations) across the major sorghum production regions in Australia in three seasons. Contributions of DTF and FTN to genetic variation in grain yield were significant in 14 and 12 tester/trial combinations, respectively. The proportion of genetic variance in grain yield explained by DTF and FTN ranged from 0.2% to 61.0% and from 1.4% to 56.9%, respectively, depending on trials and genetic background of female testers. The relationship of DTF or FTN with grain yield of hybrids was frequently positive, but varied across the genetic background of testers. Accounting for the effects of DTF and FTN using linear models did not substantially increase the between trial genetic correlations for grain yield. The results suggested that other factors affecting canopy development dynamics and grain yield might contribute GEI and/or the linear approach to account for DTF and FTN on grain yield did not capture the complex non-linear interactions.

scholarly journals The Analysis of Reproduction in Population of the Slovak Spotted Dairy Cows

2019 ◽  
Vol 67 (6) ◽  
pp. 1419-1426
Author(s):  
Jozef Bujko ◽  
Juraj Candrák ◽  
Peter Strapák ◽  
Július Žitný ◽  
Cyril Hrnčár ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Fixed Effects ◽  
Linear Models ◽  
Correlation Coefficients ◽  
Calving Interval ◽  
Factors Affecting ◽  
Actual Computation ◽  
Reproduction Traits ◽  
Days Open ◽  
Basic Statistical Analysis

The aim of study was to analyse the reproduction and factors affecting on reproduction traits of dairy cows in population of Slovak Spotted cattle from 2007 to 2016 the results for 37,274 dairy cows: days to first service (DFS), days open (DO), number of inseminations per conception (NIC), age of first calving (AFC) and calving interval (CI). The basic statistical analysis were analysed using the SAS version 9.3. For the actual computation a linear models with fixed effects was used: For the actual computation a linear models with fixed effects was used: yijklm = μ + HYSi + BTj+ Fk+ Bl +eijklm. The linear model represents coefficients determination R2 = 0.452117% (P < 0.001) for DFS, R2 = 0.377715% (P < 0.001) for DO, R2 = 0.348442% (P < 0.001) for NIC and R2 = 0.317128% (P < 0.001) for CI with all fixed effects. Correlation coefficients among DFS with DO, NIC, AFC and CI were r = 0.37275, r = -0.06881, r = 0.06493 and r = 0.08348. These coefficients were highly statistically significant (P < 0.001).

scholarly journals Invasive alien palm Pinanga coronata threatens native tree ferns in an oceanic island rainforest

2018 ◽  
Vol 66 (8) ◽  
pp. 647 ◽  
Author(s):  
Michael J. B. Dyer ◽  
Gunnar Keppel ◽  
Marika Tuiwawa ◽  
Sainivalati Vido ◽  
Hans Juergen Boehmer
Keyword(s):  
Linear Models ◽  
Management Strategies ◽  
Ornamental Plants ◽  
Native Plant ◽  
Ecological Processes ◽  
Mixed Effect ◽  
Mixed Effect Models ◽  
Tree Ferns ◽  
Native Tree ◽  
Negative Impacts

Invasive ornamental plants are a global problem that can have severe impacts on native biodiversity, especially on islands. To determine whether the invasive, ornamental ivory-cane palm Pinanga coronata could be displacing native biodiversity, we investigated its co-distribution with native tree ferns in a Fijian rainforest. We recorded the abundances of P. coronata and tree ferns and related these to environmental variables using linear models and generalised linear mixed-effect models (GLMMs). Distance to an introduction site was the most significant factor predicting the palm’s distribution and abundance, suggesting that its current distribution is limited by insufficient time for wider dispersal. P. coronata cover was strongly and negatively related with the abundance of native tree ferns and the palm may therefore be displacing native tree ferns. This relationship was strongest with tree fern seedlings and weakest with mature tree ferns, implying that the palm is preventing the establishment of native tree ferns. This study thus provides strong circumstantial evidence that P. coronata is progressively displacing native tree ferns by preventing seedling establishment and poses a severe threat to Fiji’s native biodiversity and ecological processes. Therefore, urgent management is required to control and prevent the further spread of P. coronata and its negative impacts on native plant biodiversity. Management should involve an initial feasibility study to determine the effectiveness of various management strategies, followed by targeted control and/or eradication campaigns and long-term monitoring. Ultimately, well implemented legislation to prevent the spread and introduction of P. coronata and other ornamental plants will be crucial to protect native biodiversity in Fiji and elsewhere.

scholarly journals Prerecruit survival and recruitment of northern Gulf of St Lawrence Atlantic cod

2008 ◽  
Vol 65 (6) ◽  
pp. 946-952 ◽  
Author(s):  
Daniel E. Duplisea ◽  
Dominique Robert
Keyword(s):  
Linear Models ◽  
Atlantic Cod ◽  
Information Criterion ◽  
Factors Affecting ◽  
Control Rules ◽  
Strategy Evaluation ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Long Time ◽  
Parsimonious Model

Abstract Duplisea, D. E., and Robert, D. 2008. Prerecruit survival and recruitment of northern Gulf of St Lawrence Atlantic cod. – ICES Journal of Marine Science, 65: 946–952. Recruitment (R) of exploited marine fish populations is usually modelled exclusively as a function of spawning-stock biomass (SSB). A problem arising when modelling over long time-series is that the nature of the R–SSB relationship is unlikely to be stationary. Changes are often interpreted as productivity regime shifts and are linked to alterations in prerecruit survival rate. We examine the role of environment and predation by fish and harp seals as factors affecting the R–SSB relationship in the northern Gulf of St Lawrence cod, by fitting linear models using combinations of covariates to explain cod prerecruit survival. The most parsimonious model (based on a Bayesian Information Criterion, BIC) included cod, mackerel, and temperature, whereas redfish and seals did not appear in any of the best-fit models. Recruitment models derived from this analysis could be used in operating models for management strategy evaluation simulations for northern Gulf cod, so one could develop harvest control rules that are robust to changes in recruitment productivity regimes.

scholarly journals Linear models for diallel crosses: a review with R functions

2020 ◽  
Author(s):  
Andrea Onofri ◽  
Niccolò Terzaroli ◽  
Luigi Russi
Keyword(s):  
Linear Model ◽  
Combining Ability ◽  
Linear Models ◽  
General Linear Model ◽  
Ordinary Least Squares ◽  
General Purpose ◽  
General Linear ◽  
Mixed Effect ◽  
Typical Process ◽  
R Functions

Abstract Key message A new R-software procedure for fixed/random Diallel models was developed. We eased the diallel schemes approach by considering them as specific cases with different parameterisations of a general linear model. Abstract Diallel experiments are based on a set of possible crosses between some homozygous (inbred) lines. For these experiments, six main diallel models are available in literature, to quantify genetic effects, such as general combining ability (GCA), specific combining ability (SCA), reciprocal (maternal) effects and heterosis. Those models tend to be presented as separate entities, to be fitted by using specialised software. In this manuscript, we reinforce the idea that diallel models should be better regarded as specific cases (different parameterisations) of a general linear model and might be fitted with general purpose software facilities, as used for all other types of linear models. We start from the estimation of fixed genetical effects within the R environment and try to bridge the gap between diallel models, linear models and ordinary least squares estimation (OLS). First, we review the main diallel models in literature. Second, we build a set of tools to enable geneticists, plant/animal breeders and students to fit diallel models by using the most widely known R functions for OLS fitting, i.e. the ‘lm()’ function and related methods. Here, we give three examples to show how diallel models can be built by using the typical process of GLMs and fitted, inspected and processed as all other types of linear models in R. Finally, we give a fourth example to show how our tools can be also used to fit random/mixed effect diallel models in the Bayesian framework.

Health-related quality of life (HRQoL) evaluation in the REGOMA trial: A randomized, phase II clinical trial analyzing regorafenib activity in relapsed glioblastoma patients.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 2045-2045
Author(s):  
Giuseppe Lombardi ◽  
Paola Del Bianco ◽  
Alba Ariela Brandes ◽  
Marica Eoli ◽  
Roberta Ruda ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Fixed Effects ◽  
Linear Models ◽  
Covariance Structure ◽  
Type I ◽  
Appetite Loss ◽  
Specific Domain ◽  
Mixed Effect ◽  
European Organization ◽  
Significant Difference

2045 Background: REGOMA trial showed that regorafenib (REG) significantly improved OS and PFS in relapsed glioblastoma (GBM) patients (pts) with respect to lomustine (LOM). REG showed a different toxicity profile compared to LOM. Here, we report final results of the HRQoL assessment, a secondary end point. Methods: HRQoL was measured using the European Organization for Research and Treatment of Cancer (EORTC) core questionnaire (QLQ-C30) and brain module (QLQ-BN20) administered before any MRI assessments, every 8 weeks (+/- 2 weeks) until disease progression. To evaluate treatment impact on HRQoL, questionnaires at progression were excluded. Mixed-effect linear models were fitted for each of the HRQOL domain to examine the change over progression-free time within and between arms. The models included the time of questionnaire assessment, the treatment group and their interaction, as fixed effects, and a compound symmetry covariance structure for the random effects. Differences of at least 10 points were classified as a clinically meaningful change. To correct for multiple comparisons and to avoid type I error, the level of significance was set at P = 0.01 (2-sided). Results: Of 119 randomized pts, 117 participated in the HRQoL evaluation, and 114 had a baseline assessment (n = 56 REG; n = 58 LOM). No statistically significant differences were observed in any generic or cancer specific domain during treatment in the REG and LOM arms, or between the two arms, except for the appetite loss scale which was significantly worse in PTS treated with REG (Global mean 14.7 (SD = 28.6) vs 7.6 (SD = 16.0); p = 0.0081). The proportion of pts with a clinically meaningful worsening for appetite loss was not statistically different between the two arms (9 out of 24 and 0 out of 13 in the REG and LOM arm, respectively; p = 0.0146). Conclusions: In the REGOMA trial, HRQoL did not change during REG treatment. Pts treated with REG and LOM reported no significant difference in HRQoL. Clinical trial information: NCT02926222. [Table: see text]

Factors affecting commercial trawl fleet landings in a multispecies fishery

2003 ◽  
Vol 83 (1) ◽  
pp. 205-215 ◽  
Author(s):  
M. Labropoulou ◽  
C.D. Maravelias ◽  
C. Papaconstantinou
Keyword(s):  
Total Variation ◽  
Generalized Linear Models ◽  
Linear Models ◽  
Factors Affecting ◽  
Abundance Indices ◽  
Vessel Capacity ◽  
Main Effects ◽  
Trawl Fisheries ◽  
Fishing Area ◽  
Modelling Approach

Retained catches of trawl fleet in Chalkis fishing port-market, Greece, were analysed using generalized linear models (GLMs) in an attempt to identify factors that influence the total landings of the groundfish fisheries. Main effects in the model included a factor for vessel tonnage that determined fishing power, as well as factors for month and fishing area. Covariates examined were all found to have a significant effect on the retained catches, with month and vessel capacity alone explaining 38% and 30% respectively of the total variation of the data. Significant interactions observed indicate that the fluctuations in retained catch differed by fishing area and month as well as by fishing area and vessel category. Within vessel categories, month and fishing area also had significant effects on the retained catches, with fishing area being more important than month for the smallest vessels. Results indicate that the modelling approach of retained catches from trawl fisheries is a promising method for obtaining representative abundance indices.

Sign in / Sign up

Export Citation Format

Share Document