A sequential multi-level framework to improve habitat suitability modelling

Landscape Ecology - Habitat suitability models (HSM) can improve our understanding of a species’ ecology and are valuable tools for informing landscape-scale decisions. We can increase HSM...     

Severe modifications in source-sink ratio influence the susceptibility of bananas to crown rot and its phenolics content

Banana susceptibility to crown rot is influenced by many biotic and abiotic preharvest factors, which include source-sink (So-Si) ratio modifications through trimming of leaves and fruit. Banana plant's resistance to biotic stress has been previously correlated to its phenolic content; it is hypothesized that the crown's phenolic content may influence the fruit's susceptibility. The aim of this work was to investigate the influence of severe So-Si ratio modifications, via the removal of leaves and fruit, and the involvement of phenolics in the fruit's susceptibility to crown rot. Fruit susceptibility was evaluated 13 days postinoculation (13 dpi) with Colletotrichum musae. Banana crowns obtained on the day of harvest before inoculation (dhbi) and 13 dpi were analysed for changes in phenolics using GC-MS, HPLC, and LC-MS devices. Severe So-Si ratio modifications had a significant effect (p <.001) on susceptibility, fruits of low So-Si ratio being most susceptible. It also significantly influenced (p < .001) some tree and fruit characteristics. The less susceptible (S−) crowns had higher amounts of phenolics compared to the more susceptible (S+) ones. Catecholamines were identified as the major phenolics in banana crown, notably dopamine compared to norepinephrine and normetanephrine. Hydroxycinnamic acids (ferulic acid and its derivatives) were significantly accumulated (p <.001) the dhbi in S− crowns compared to S+ crowns, but decreased 13 dpi. Phenolics have a possible role in the biochemical defence of banana crown and could be used by producers as a chemical criterion for estimation of the level of banana's susceptibility to crown rot.     

Utility of high-density plantings in bay scallop, Argopecten irradians irradians, restoration

Two different methods of establishing high-density spawner sanctuaries for bay scallop (Argopecten irradians irradians) restoration were evaluated over 2 years at a site in Northwest Harbor, East Hampton, New York, USA. Hatchery-reared scallops, which had been overwintered at nearby sites, were free-planted directly to the bottom in late March/early April at an initial target density of 94?C128 scallops/m². In addition, scallops were stocked in off-bottom culture units consisting of three vertically stacked 15-mm mesh ADPI^® bags at densities of 50, 100, or 200 scallops/bag (=117, 234, or 468 scallops/m²), respectively. Survival of scallops differed significantly by year, planting method, and scallop source. Survival of free-planted scallops was generally lower than caged scallops. Better survival of free-planted scallops in 2005 versus 2006 likely reflected the presence of luxuriant eelgrass beds in 2005, which were absent in 2006. Survival of scallops in ADPI bags was not appreciably related to stocking density. Shell growth was highest for free-planted scallops; in cages, growth was somewhat better at 50 versus 200 scallops/bag. Wet weights of epibionts were significantly higher in caged versus free-planted scallops. Reproductive condition of scallops stocked at 50/bag was usually higher than at 200/bag. Both free-planting and off-bottom systems yielded high densities of adult bay scallops at the time of spawning, which ensures a higher probability of successful fertilization of spawned eggs and thus a greater potential for success of restoration efforts.     

The ecological basis of freshwater pond management for biodiversity

1. Macrophyte and macroinvertebrate species richness, and the extent of aquatic vegetation, were surveyed in 51 newly created or renovated ponds in mid and west Wales, together with a range of environmental variables. These data are analysed in relation to management issues including pond size, rate of development, planting for oxygenation, stocking with fish and shading by riparian trees. 2. Richness of both plants and invertebrates increases with vegetated area, but the relationships are weak. Similarities among assemblages in ponds are low and not related to the proximity of the ponds. It is likely that two small ponds would together support more species than a single large pond. 3. New ponds are colonized rapidly by plants and invertebrates. There is no relationship between age and the number of species in ponds that were at least one year old, except for invertebrates in ponds that were isolated from other wetland. As expected, the extent of aquatic vegetation increases with age. 4. Minimum dissolved oxygen levels decrease with the cover of floating plants and with extent of vegetation in relation to pond size. 5. There is no evidence that stocking with fish (mainly salmonids at low densities) influences the total number of species of either macrophytes or macroinvertebrates. However, the number of anisopteran (Insecta: Odonata) species is lower in stocked ponds and the number of trichopteran (Insecta) species is higher. 6. Macrophyte species richness increases with the percentage of the margin shaded by trees to a peak between 22% (emergent species) and 30% (submerged and floating species), and then declines. The number of species of invertebrates with short-lived flying adults (Odonata, Ephemeroptera, Trichoptera) decreases with the extent of riparian trees. Other invertebrates are unaffected. 7. The relationship between the survey results and existing management recommendations is discussed, emphasizing the need for field experiments to provide empirical support. © 1997 John Wiley & Sons, Ltd.     

Eimeria stiedae causes most of the white-spotted liver lesions in wild European rabbits in Cambridgeshire,United Kingdom

In rabbits, a white-spotted liver can be indicative of one of several disease processes, frequently caused by parasites. To date, the prevalence of white-spotted liver in wild rabbits, Oryctolagus cuniculus, in the United Kingdom is undetermined. We evaluated the prevalence and main parasitic etiologies of this entity in a U.K. population of wild rabbits. Wild rabbits (n = 87) were shot in Cambridgeshire for population control, and cadavers were donated for research. Postmortem examination was undertaken, including gross and histologic hepatic examination. Macroscopic lesions consistent with white-spotted liver were found in 46 of 87 (53%) rabbits examined; most of these lesions were considered to be mild. For 28 of 46 (59%) rabbits with gross hepatic lesions, an etiologic agent was apparent histologically. Eimeria stiedae was detected in 21 of 87 (24%) rabbits, and Calodium hepaticum (syn. Capillaria hepatica) was detected in 7 of 87 (8%). In the subset of rabbits killed in the summer, there was a significant association between white-spotted liver and juvenile age class. There was also an association between white-spotted liver caused by E. stiedae and juvenile age class. When restricting analysis to rabbits with white-spotted liver caused by E. stiedae and submitted in the summer, both juvenile age class and female had significant effects. E. stiedae and C. hepaticum can be transmitted to pet lagomorphs via contaminated vegetation, and to humans in the case of the latter, which demonstrates the importance of monitoring the prevalence of these parasitic diseases in wild rabbits.     

Esophageal varices in dogs: A retrospective case series

BackgroundEsophageal varices (EV) are abnormally dilated veins in the esophagus caused by alterations of blood flow or pressure. Esophageal variceal hemorrhage is a major complication of hepatic disease in humans, but a lack of information exists regarding associated adverse events in dogs.ObjectiveTo describe the clinical manifestations and associated etiologies and outcomes of dogs with EV.AnimalsTwenty‐five client‐owned dogs with EV diagnosed via computed tomography (CT), endoscopy, or fluoroscopy.MethodsRetrospective case series. Cases were identified by review of the hospital imaging records database between 2010 and 2020. Signalment, clinical signs, and outcomes were documented. When present, additional collateral vasculature was also recorded. Cases were subcategorized into suspected etiology based upon the anatomic location or absence of an attributable underlying disease process, as well as the direction of blood flow.ResultsTwenty‐four of 25 cases were identified via CT, with a prevalence of 0.012% (24/1950 total studies). Presenting clinical signs were nonspecific, and more likely because of the underlying cause as opposed to complications secondary to EV themselves. Etiologic anatomic locations were similar in occurrence between the abdomen (N = 14) and thorax (N = 11). All cases with an abdominal etiologic location had presumed or confirmed portal hypertension and 9/11 cases with a thoracic etiologic location had pulmonary, caval, or systemic hypertension. No cases died or were euthanized as a direct result of EV or associated hemorrhage.Conclusions and Clinical ImportanceEsophageal varices are rarely reported in dogs and commonly identified concurrently with portal, pulmonary, and caval hypertension. Hemorrhage is not a common clinical manifestation of EV.     

Prospective study of dilated cardiomyopathy in dogs eating nontraditional or traditional diets and in dogs with subclinical cardiac abnormalities

BackgroundRecent studies have investigated dogs with presumed diet‐associated dilated cardiomyopathy (daDCM), but prospective studies of multiple breeds are needed.Hypothesis/ObjectivesTo evaluate baseline features and serial changes in echocardiography and cardiac biomarkers in dogs with DCM eating nontraditional diets (NTDs) or traditional diets (TDs), and in dogs with subclinical cardiac abnormalities (SCA) eating NTD.AnimalsSixty dogs with DCM (NTD, n = 51; TDs, n = 9) and 16 dogs with SCA eating NTDs.MethodsEchocardiography, electrocardiography, and measurement of taurine, cardiac troponin I, and N‐terminal pro‐B‐type natriuretic peptide were performed in dogs with DCM or SCA. Diets were changed for all dogs, taurine was supplemented in most, and echocardiography and cardiac biomarkers were reassessed (3, 6, and 9 months).ResultsAt enrollment, there were few differences between dogs with DCM eating NTDs or TDs; none had low plasma or whole blood taurine concentrations. Improvement in fractional shortening over time was significantly associated with previous consumption of a NTD, even after adjustment for other variables (P = .005). Median survival time for dogs with DCM was 611 days (range, 2‐940 days) for the NTD group and 161 days (range, 12‐669 days) for the TD group (P = .21). Sudden death was the most common cause of death in both diet groups. Dogs with SCA also had significant echocardiographic improvements over time.Conclusions and Clinical ImportanceDogs with DCM or SCA previously eating NTDs had small, yet significant improvements in echocardiographic parameters after diet changes.     

Creating community‐based indicators of gender equity: A methodology

It appears that an almost unquestioned development pathway for achieving gender equity and women's empowerment has taken centre stage in mainstream development. This pathway focuses on economic outcomes that are assumed to be achieved by increasing women's access to material things, including cash income, loans, physical assets, and to markets. Gender equity indicators, which measure progress towards these outcomes, cannot escape reinforcing them. We argue that far from being neutral, indicators are embedded in political and ideological agendas that serve as guides to the appropriate conduct of those whose performance or behaviour is being measured. Drawing on participatory feminist, diverse economies and strengths based approaches, we outline a research methodology for developing community‐based indicators that recognises women's and men's participation and relationships in all spheres of life, including the ‘non‐economic’. If indicators are grounded in local meanings and realities, we propose that community members can use them to identify aspirational goals for gender equity, and measure progress towards these goals.     

Using a species-centered approach to predict bird community responses to habitat fragmentation

Landscape Ecology - The relative importance of habitat fragmentation versus loss on species richness has been much debated. However, recent findings that fragmentation effects are relatively weak...