An increase in habitat complexity is thought to decrease visibility and the territory size of visually oriented animals. Hence, the addition of physical structure has been viewed as a useful ...restoration technique to increase the density of territorial species, particularly in stream fishes. However, a decrease in territory size may have a negative effect on the fitness of individual organisms. We attempted to quantify some of the positive and negative effects of increasing habitat structure on the behaviour and growth rate of wild young‐of‐the‐year (YOY) Atlantic salmon. Fish were exposed to one of two habitat treatments in mesh enclosures in Catamaran Brook, New Brunswick: a gravel substrate (low complexity) or a gravel substrate with boulders added (high complexity). Wild‐caught individuals were tagged, weighed and measured before being stocked at densities of 1·m⁻² for 7‐d trials. While fish from high‐complexity treatments benefited from lower rates of aggression, they also had lower foraging rates and smaller territories compared to those in low‐complexity treatments. Specific growth rate, however, did not differ significantly between treatments. While the addition of structure to a habitat may be beneficial at the population level in terms of an increase in population density, our results suggested that individual fish may pay some short‐term costs in these environments. Further research is needed to evaluate the longer term costs and benefits of adding structure to improve the habitat quality for stream salmonids.
The community adherence support group (CASG) was one of the first differentiated service delivery (DSD) models introduced in Mozambique. This study assessed the impact of this model on retention in ...care, loss to follow-up (LTFU), and viral suppression among antiretroviral therapy (ART)-treated adults in Mozambique. A retrospective cohort study included CASG-eligible adults enrolled between April 2012 and October 2017 at 123 health facilities in Zambézia Province. Propensity score matching (1:1 ratio) was used to allocate CASG members and those who never enrolled in a CASG. Logistic regressions were performed to estimate the impact of CASG membership on 6- and 12-month retention and viral load (VL) suppression. Cox proportional regression was used to model differences in LTFU. Data from 26,858 patients were included. The median age at CASG eligibility was 32 years and 75% were female, with 84% residing in rural areas. A total of 93% and 90% of CASG members were retained in care at 6 and 12 months, respectively, while 77% and 66% non-CASG members were retained during the same periods. The odds of being retained in care at 6 and 12 months were significantly higher among patients receiving ART through CASG support (adjusted odds ratio aOR = 4.19 95% confidence interval; CI: 3.79-4.63,
< .001, and aOR = 4.43 95% CI: 4.01-4.90,
< .001, respectively). Among 7,674 patients with available VL measurements, the odds of being virally suppressed were higher among CASG members (aOR = 1.14 95% CI: 1.02-1.28,
< .001). Non-CASG members had a significantly higher likelihood of being LTFU (adjusted hazard ratio = 3.45 95% CI: 3.20-3.73,
< .001). While Mozambique rapidly scales up multi-month drug dispensation as the preferred DSD model, this study emphasizes the continued importance of CASG as an efficacious DSD alternative, especially among patients residing in rural areas, where CASG acceptability is higher.
