Superficial corneal squamous cell carcinoma occurring in dogs with chronic keratitis

Objective Canine corneal squamous cell carcinoma (SCC) is a rare tumor, with only eight cases previously published in the veterinary literature. The Comparative Ocular Pathology Lab of Wisconsin (COPLOW) has diagnosed 26 spontaneously occurring cases, 23 in the past 4 years. This retrospective study describes age and breed prevalence, concurrent therapy, biologic behavior, tumor size and character, and 6‐month survival rates after diagnosis. Results A search of the COPLOW database identified 26 corneal SCC cases diagnosed from 1978 to 2008. There is a strong breed predilection (77%) in brachycephalic breeds, particularly those prone to keratoconjunctivitis sicca. The mean age was 9.6 years (range 6–14.5 years). Follow‐up information >6 months was available for 15 of 26 cases. Recurrence occurred in the same eye in nine cases, seven of which were incompletely excised at the time of first keratectomy. No cases were known to have tumor growth in the contralateral eye and no cases of distant metastases are known. Where drug history is known, 16 of 21 dogs had a history of treatment with topical immunosuppressive therapy (cyclosporine or tacrolimus) at the time of diagnosis. Conclusion Chronic inflammatory conditions of the cornea and topical immunosuppressive therapy may be risk factors for developing primary corneal SCC in dogs. SCC should be considered in any differential diagnosis of corneal proliferative lesions. Superficial keratectomy with complete excision is recommended, and the metastatic potential appears to be low.     

Tetralogy of Fallot in a Young Ferret (Mustela putorius furo)

A 17-month-old albino, castrated male domestic ferret (Mustela putorius furo) was presented for evaluation of a heart murmur. The murmur was first auscultated when the ferret was 12 weeks of age, coinciding with its first known evaluation by a veterinarian. At the time of diagnosis, the ferret was reported to have mild exercise intolerance. The clinical findings on the ferret were within normal limits other than a right parasternal systolic murmur (grade 4/6) that radiated to the left parasternal region. The ferret was not receiving any medications. All 4 features of tetralogy of Fallot (TOF) were identified with echocardiography. Thoracic radiographs were suggestive of TOF with mild right-sided enlargement of the cardiac silhouette and small pulmonary vasculature. A serum biochemistry profile and complete blood count were within the reference ranges for domestic ferrets. At that time atenolol (3.25 mg, every 24 hours, orally) was prescribed to treat the clinical condition of the animal. At a 1-week follow-up examination, the patient's heart rate had decreased from 240-300 beats per minute to 180-260 beats per minute. The owner reported that the ferret was sleeping more frequently during the first week of therapy but had normal activity when awake. At a 5-month recheck examination, the patient was reported to be completely normal at home. This is the first case report of TOF in a ferret.     

Modeling occupancy dynamics of a rare species,Franklin’s ground squirrel,with limited data: are simple connectivity metrics adequate?

Conservation of populations in fragmented habitats is often based on spatially realistic metapopulation theory, which predicts negative relationships between patch extinction and area and patch colonization and isolation. Cost-distance metrics have been developed to integrate habitat quality into measures of connectivity, and thus may improve predictive power of the area-isolation paradigm. Few studies use empirical data to compare predictive performance of complex cost-distance metrics to simple metrics relying on Euclidean distances. We used 3 years of presence–absence data to examine relative influence of habitat quality, habitat area, and connectivity on occupancy and extinction rates for Poliocitellus franklinii (Franklin’s ground squirrel), a rare grassland species of conservation concern. We calculated connectivity using nearest-neighbor (NN) and incidence function model (IFM) metrics based on Euclidean and cost-distances. Habitat quality, area, and connectivity were all positive predictors for occupancy, but only isolation was a positive predictor of extinction. P. franklinii does not appear to be a tallgrass prairie obligate, but the species distribution is limited by isolation of suitable grassland habitat. A simple NN metric measuring Euclidean distance between a target area and nearest occupied source outperformed IFM (Euclidean and cost-distance) in predicting occupancy and extinction for P. franklinii. Although NN metrics are criticized for considering only the contribution of the source nearest to a target, this simplicity may be acceptable when measuring connectivity for rare species with few occupied habitat patches within dispersal distance.     

Forest type influences transmission of Phytophthora ramorum in California oak woodlands

The transmission ecology of Phytophthora ramorum from bay laurel (Umbellularia californica) leaves was compared between mixed-evergreen and redwood forest types throughout winter and summer disease cycles in central, coastal California. In a preliminary multisite study, we found that abscission rates of infected leaves were higher at mixed-evergreen sites. In addition, final infection counts were slightly higher at mixed-evergreen sites or not significantly different than at redwood sites, in part due to competition from other foliar pathogens at redwood sites. In a subsequent, detailed study of paired sites where P. ramorum was the main foliar pathogen, summer survival of P. ramorum in bay laurel leaves was lower in mixed-evergreen forest due to lower recovery from infected attached leaves and higher abscission rates of infected leaves. Onset of inoculum production and new infections of bay laurel leaves occurred later in mixed-evergreen forest. Mean inoculum levels in rainwater and final infection counts on leaves were higher in redwood forest. Based on these two studies, lower summer survival of reservoir inoculum in bay laurel leaves in mixed-evergreen forest may result in delayed onset of both inoculum production and new infections, leading to slower disease progress in the early rainy season compared with redwood forest. Although final infection counts also will depend on other foliar pathogens and disease history, in sites where P. ramorum is the main foliar pathogen, these transmission patterns suggest higher rates of disease spread in redwood forests during rainy seasons of short or average length.     

Food for thought: Risks of non-native species transfer to the Antarctic region with fresh produce

To understand fully the risk of biological invasions, it is necessary to quantify propagule pressure along all introduction pathways. In the Antarctic region, importation of fresh produce is a potentially high risk, but as yet unquantified pathway. To address this knowledge gap, >11,250 fruit and vegetables sent to nine research stations in Antarctica and the sub-Antarctic islands, were examined for associated soil, invertebrates and microbial decomposition. Fifty-one food types were sourced from c. 130 locations dispersed across all six of the Earth’s inhabited continents. On average, 12% of food items had soil on their surface, 28% showed microbial infection resulting in rot and more than 56 invertebrates were recorded, mainly from leafy produce. Approximately 30% of identified fungi sampled from infected foods were not recorded previously from within the Antarctic region, although this may reflect limited knowledge of Antarctic fungal diversity. The number of non-native flying invertebrates caught within the Rothera Research Station food storage area was linked closely with the level of fresh food resupply by ship and aircraft. We conclude by presenting practical biosecurity measures to reduce the risk of non-native species introductions to Antarctica associated with fresh foods.     

Size, species, and fire behavior predict tree and liana mortality from experimental burns in the Brazilian Amazon

Anthropogenic understory fires have affected large areas of tropical forest in recent decades, particularly during severe droughts. Yet, the mechanisms that control fire-induced mortality of tropical trees and lianas remain ambiguous due to the challenges associated with documenting mortality given variation in fire behavior and forest heterogeneity. In a seasonally dry Amazon forest, we conducted a burn experiment to quantify how increasing understory fires alter patterns of stem mortality. From 2004 to 2007, tree and liana mortality was measured in adjacent 50-ha plots that were intact (B0 - control), burned once (B1), and burned annually for 3 years (B3). After 3 years, cumulative tree and liana mortality (≥1 cm dbh) in the B1 (5.8% yr⁻¹) and B3 (7.0% yr⁻¹) plots significantly exceeded mortality in the control (3.2% yr⁻¹). However, these fire-induced mortality rates are substantially lower than those reported from more humid Amazonian forests. Small stems were highly vulnerable to fire-induced death, contrasting with drought-induced mortality (measured in other studies) that increases with tree size. For example, one low-intensity burn killed >50% of stems <10 cm within a year. Independent of stem size, species-specific mortality rates varied substantially from 0% to 17% yr⁻¹ in the control, 0% to 26% yr⁻¹ in B1, and 1% to 23% yr⁻¹ in B3, with several species displaying high variation in their vulnerability to fire-induced mortality. Protium guianense (Burseraceae) exhibited the highest fire-induced mortality rates in B1 and B3, which were 10- and 9-fold greater than the baseline rate. In contrast, Aspidosperma excelsum (Apocynaceae), appeared relatively unaffected by fire (0.3% to 1.0% mortality yr⁻¹ across plots), which may be explained by fenestration that protects the inner concave trunk portions from fire. For stems ≥10 cm, both char height (approximating fire intensity) and number of successive burns were significant predictors of fire-induced mortality, whereas only the number of consecutive annual burns was a strong predictor for stems <10 cm. Three years after the initial burn, 62 ± 26 Mg ha⁻¹ (s.e.) of live biomass, predominantly stems <30 cm, was transferred to the dead biomass pool, compared with 8 ± 3 Mg ha⁻¹ in the control. This biomass loss from fire represents ∼30% of this forest's aboveground live biomass (192 (±3) Mg ha⁻¹; >1 cm DBH). Although forest transition to savanna has been predicted based on future climate scenarios, our results indicate that wildfires from agricultural expansion pose a more immediate threat to the current carbon stocks in Amazonian forests.     

Effect of sea-level rise on piping plover (Charadrius melodus) breeding habitat

Climate change is raising sea levels, threatening many low-lying coastal areas and associated wildlife. We assessed the threat of sea-level rise (SLR) to the breeding habitat of the federally threatened piping plover on the barrier islands of Suffolk County, New York. We determined the extent of habitat change over the next 100 years under several SLR estimates, as well as the interactive effects of coastal development and storm surge. We found that if plover habitat cannot migrate, SLR is likely to reduce breeding areas. However, if habitat is able to migrate upslope and inland, breeding areas could actually increase with SLR. Unfortunately, this potential habitat gain is stymied by human development, which we found to reduce migrating habitat by 5–12%, depending on SLR estimates. We also found that the spatial configuration of developed areas mattered more than intensity of development in blocking the migration of potential habitat area. Our results raise concern over the likelihood of increased conflict between plover habitat protection and human recreation as habitat is likely to become a larger proportion of the barrier islands in the future. Finally, our results highlight risk from the synergism between SLR and coastal storms, as we estimate that a large hurricane could flood up to 95% of plover habitat. To assure the future of plover habitat on these barrier islands, management needs to promote natural overwash and habitat migration, while minimizing development adjacent to future breeding habitat.