From past patterns to future potential: using historical ecology to inform river restoration on an intermittent California river

Context

Effective river restoration requires understanding a system’s potential to support desired functions. This can be challenging to discern in the modern landscape, where natural complexity and heterogeneity are often heavily suppressed or modified. Historical analysis is therefore a valuable tool to provide the long-term perspective on riverine patterns, processes, and ecosystem change needed to set appropriate environmental management goals and strategies.

Objective

In this study, we reconstructed historical (early 1800s) riparian conditions, river corridor extent, and dry-season flow on the lower Santa Clara River in southern California, with the goal of using this enhanced understanding to inform restoration and management activities.

Method

Hundreds of cartographic, textual, and visual accounts were integrated into a GIS database of historical river characteristics.

Results

We found that the river was characterized by an extremely broad river corridor and a diverse mosaic of riparian communities that varied by reach, from extensive (>100 ha) willow-cottonwood forests to xeric scrublands. Reach-scale ecological heterogeneity was linked to local variations in dry-season water availability, which was in turn underpinned by regional geophysical controls on groundwater and surface flow.

Conclusions

Although human actions have greatly impacted the river’s extent, baseflow hydrology, and riparian habitats, many ecological attributes persist in more limited form, in large part facilitated by these fundamental hydrogeological controls. By drawing on a heretofore untapped dataset of spatially explicit and long-term environmental data, these findings improve our understanding of the river’s historical and current conditions and allow the derivation of reach-differentiated restoration and management opportunities that take advantage of local potential.

     

Cytologic identification of fungal arthritis in a Labrador Retriever with disseminated Talaromyces helicus infection

An 8‐year‐old, neutered male Labrador Retriever presented with acute forelimb lameness. Clinical signs progressed over one week. On physical examination, right cubital joint effusion and bilateral axillary lymphadenomegaly were noted, and severe internal lymphadenomegaly was observed ultrasonographically. Granulomatous lymphadenitis with intralesional fungi was noted cytologically, and the dog was ultimately diagnosed with disseminated Talaromyces helicus infection via PCR of a pure isolate. Extensive medical therapy was pursued, and months later, an arthrocentesis was performed due to continued lameness and severe cubital joint effusion. The synovial fluid contained increased numbers of neutrophils, macrophages, and multinucleated giant cells. Frequent fungal hyphae were found both intracellularly and extracellularly. These basophilic organisms were 2‐4 µm in width with internal eosinophilic granules, roughly parallel walls, and occasional to frequent septa. Round to oval yeast‐like forms with thin, clear halos were also occasionally identified. Due to the severity of clinical signs, the right thoracic limb was amputated. Histologic examination of the cubital joint revealed marked granulomatous synovitis, fasciitis, panniculitis, and osteomyelitis, all with intralesional fungi. Talaromyces helicus is a very rare cause of disease, reported only in one other dog. Granulomatous lymphadenitis appears to be a feature of this disease, but this report is the first to describe a significant synovial component.     

Livestock and livelihoods of smallholder cattle-owning households in Cambodia: the contribution of on-farm and off-farm activities to income and food security

The majority of smallholder farming households in Cambodia are rurally based and rely on agriculture to support their livelihoods. However, in recent years, growth in the agriculture sector has stagnated with farmers facing several challenges including declining prices for traditional crops and irregular rainfall patterns. This has led to a need for farmers to diversify income sources with livestock promoted as a more viable livelihood activity, particularly the raising of cattle and poultry. However, uncertain profitability of livestock activities is a common perception by smallholders, especially where animals have not been traditionally viewed as a primary income source. To address this, information is required which compares the income and expenses associated with livestock raising to other on-farm activities and off-farm sources. This study reports on a survey of livelihood survey of 17 male and 21 female representatives of 20 households owning cattle in Cambodia, comparing the associated income and expenses of the various livelihood activities in the 12-month period from January to December 2016. Combined total household income from both on-farm and off-farm sources ranged from USD875 to 17730 with an average of USD6779, representing 51% and 49% from on-farm and off-farm activities, respectively. Cattle raising was the most common source of on-farm income (85%), contributing USD1064 and representing 22% of total household income. General household expenses, such as food and transportation (including expenses associated with off-farm employment), represented the majority of total household expenses (79%). Gross profit calculations indicated higher values for pig raising (USD1841.79), cattle (USD950.80) and non-rice crops (USD884) whilst the highest gross margin value was recorded for cattle (89.33%) followed by vegetables (85.27%) and non-rice crops (83.08%). Whilst wet season and dry season rice returned a negative gross profit value of USD197.27 and USD90.60 on average per household, respectively, both were ranked as most important for household consumption, followed by poultry, providing the main source of energy (rice) and protein (chicken meat) and sustaining household food requirements. The study concludes that although smallholder cattle-owning households in Cambodia undertake a diverse range of on-farm activities, as cattle raising provides a superior income source due to higher returns and lower variable costs, it could be promoted as a preferred livelihood activity by agencies conducting rural extension activities. Although consideration of available labour and monetary funds to invest in cattle raising is required, it was observed that income from off-farm sources may prove beneficial in providing the additional monetary funds to support cattle-raising activities and assist in providing generally poor smallholder households with enhanced economic resilience.     

The North American Animal Disease Spread Model: a simulation model to assist decision making in evaluating animal disease incursions

The North American Animal Disease Spread Model is a stochastic, spatial, state-transition simulation model for the spread of highly contagious diseases of animals. It was developed with broad international support to assist policy development and decision making involving disease incursions. User-established parameters define model behavior in terms of disease progression; disease spread by animal-to-animal contact, contact with contaminated personnel or equipment, and airborne dissemination; and the implementation of control measures such as destruction and vaccination. Resources available to implement disease control strategies, as well as the direct costs associated with these strategies, are taken into consideration. The model records a wide variety of measures of the extent of simulated outbreaks and other characteristics. The graphical interface and output visualization features also make it a useful tool for training and preparedness exercises. This model is now being used to evaluate outbreak scenarios and potential control strategies for several economically important exotic animal diseases in the United States, Canada, and elsewhere. NAADSM is freely available via the Internet at http://www.naadsm.org.     

Evaluation of indirect blood pressure monitoring in awake and anesthetized red-tailed hawks (Buteo jamaicensis): effects of cuff size, cuff placement, and monitoring equipment

ObjectiveTo compare Doppler and oscillometric methods of indirect arterial blood pressure (IBP) with direct arterial measurements in anesthetized and awake red-tailed hawks.Study designProspective, randomized, blinded study.AnimalsSix, sex unknown, adult red-tailed hawks.MethodsBirds were anesthetized and IBP measurements were obtained by oscillometry (IBP-O) and Doppler (IBP-D) on the pectoral and pelvic limbs using three cuffs of different width based on limb circumference: cuff 1 (20–30% of circumference), cuff 2 (30–40%), and cuff 3 (40–50%). Direct arterial pressure measurements were obtained from the contralateral superficial ulnar artery. Indirect blood pressure measurements were compared to direct systolic arterial pressure (SAP) and mean arterial pressure (MAP) during normotension and induced states of hypotension and hypertension. Measurements were also obtained in awake, restrained birds. Three-way anova, linear regression and Bland–Altman analyses were used to evaluate the IBP-D data. Results are reported as mean bias (95% confidence intervals).ResultsThe IBP-O monitor reported errors during 54% of the measurements. Indirect blood pressure Doppler measurements were most accurate with cuff 3 and were comparable to MAP with a bias of 2 (?9, 13 mmHg). However, this cuff consistently underestimated SAP with a bias of 33 (19, 48 mmHg). Variability in the readings within and among birds was high. There was no significant difference between sites of cuff placement. Awake birds had SAP, MAP and diastolic arterial pressure that were 56, 43, and 38 mmHg higher than anesthetized birds.Conclusions and clinical relevanceIndirect blood pressure (oscillometric) measurements were unreliable in red-tailed hawks. Indirect blood pressure (Doppler) measurements were closer to MAP measurements than SAP measurements. There was slightly better agreement with the use of cuff 3 on either the pectoral or pelvic limbs. Awake, restrained birds have significantly higher arterial pressures than those under sevoflurane anesthesia.     

Effect of oral melatonin administration on sex hormone, prolactin, and thyroid hormone concentrations in adult dogs.

OBJECTIVE: To determine the effect of oral melatonin (MT) administration on serum concentrations of sex hormones, prolactin, and thyroxine in dogs. DESIGN: Prospective study. ANIMALS: 8 male and 8 female adult sexually intact dogs. PROCEDURE: 5 male and 5 female dogs were treated with MT (1.0 to 1.3 mg/kg [0.45 to 0.59 mg/lb] of body weight), PO, every 12 hours for 28 days; the other 6 dogs were used as controls. Blood samples were collected on days 0, 14, and 28, and serum concentrations of estradiol-17 beta, progesterone, testosterone, androstenedione, 17-hydroxyprogesterone (17-HP), dihydroepiandrostenedione sulfate (DHEAS), prolactin, and thyroxine were determined. On day 5, serum MT concentrations were measured before and periodically for up to 8 hours after MT administration in 4 treated dogs. RESULTS: Female dogs treated with MT had significant decreases in serum estradiol, testosterone, and DHEAS concentrations between days 0 and 28. Male dogs treated with MT had significant decreases in serum estradiol and 17-HP concentrations between days 0 and 28. Serum MT concentrations increased significantly after MT administration and remained high for at least 8 hours. Prolactin and thyroxine concentrations were unaffected by treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Melatonin is well absorbed following oral administration and may alter serum sex hormone concentrations.     

Ultrasonographic appearance and abdominal haemorrhage associated with a juvenile granulosa cell tumour in a foal

Granulosa cell tumours are commonly identified in mares, but have rarely been identified in equine neonates. This report describes a septic neonatal foal that presented with haemoabdomen secondary to a ruptured ovarian granulosa cell tumour. The ultrasonographic appearance, successful surgical removal and histopathological appearance of the tumour is described. Juvenile ovarian granulosa cell tumours differ histologically from adult granulosa cell tumours. Ultrasound is a useful way to identify haemoabdomen and abdominal masses in foals. Juvenile granulosa cell tumour should be considered as a differential for this combination in neonatal foals.     

Epidemiologic characterization of Colorado backyard bird flocks

Backyard gallinaceous bird flocks may play an important role in the spread of infectious diseases within poultry populations as well as the transmission of zoonotic diseases to humans. An epidemiologic characterization was conducted of Colorado backyard flocks to gather information on general flock characteristics, human movement of birds, human-bird interaction, biosecurity practices, and flock health. Our results suggest that backyard poultry flocks in Colorado are small-sized flocks (68.6% of flocks had < 50 birds); consist primarily of layer chickens (85.49% of flocks), show chickens (32.18% of flocks), and waterfowl (34.07% of flocks); and are primarily owned for food (meat or egg) production for the family (86.44%) or as pet or hobby birds (42.27%). The backyard flock environment may promote bird-to-bird transmission as well as bird-to-human transmission of infectious disease. Birds are primarily housed with free access to the outside (96.85%), and many are moved from the home premises (46.06% within 1 yr). Human contact with backyard flocks is high, biosecurity practices are minimal, and bird health is negatively impacted by increased movement events. Increased knowledge of backyard bird characteristics and associated management practices can provide guidelines for the development of measures to decrease disease transmission between bird populations, decrease disease transmission from birds to humans, and increase the overall health of backyard birds.