Effectiveness of population-based recovery actions for threatened southern mountain caribou.

Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973-2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population-based recovery actions at increasing population growth. Reducing potential limiting factors on threatened caribou populations offered a rare opportunity to identify the causes of decline and assess methods of recovery. Southern mountain caribou abundance declined by 51% between 1991 and 2023, and 37% of subpopulations were functionally extirpated. Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation, and combinations of wolf reductions with maternal penning or supplemental feeding provided rapid growth but were applied to only four subpopulations. As of 2023, recovery actions have increased the abundance of southern mountain caribou by 52%, compared to a simulation with no interventions. When predation pressure was reduced, rapid population growth was observed, even under contemporary climate change and high levels of habitat loss. Unless predation is reduced, caribou subpopulations will continue to be extirpated well before habitat conservation and restoration can become effective.

A Pilot Study of Nutritional Supplementation in Soft Tissue Sarcoma Patients.

Background: Wound healing is particularly important for sarcoma patients who undergo neoadjuvant radiation therapy. Previous studies have demonstrated wound complications in this population approaching 35%. With this high rate of wound healing issues, identifying treatment modalities to minimize these complications is of paramount importance. Methods: All patients with high grade bone and soft tissue sarcoma received 15 days of twice daily amino acid supplementation starting in the immediate post-operative period. We documented the healing status of the surgical wound, the primary outcome, at all follow up appointments until six months after surgery. Non-healing wounds were defined as any wound requiring 1) a return visit to the OR for debridement, 2) IV antibiotics (ABX), and 3) unhealed wounds at 6 months post-operatively.1 For each patient, we collected biometrics with lean body mass analysis at preoperative appointment, and two and six weeks postoperatively. The proportion with non-healing wounds was compared with a historical patient cohort using the chi-square test. In a subgroup of participants with body composition measurements, we also compared changes in mean fat mass, lean mass, and psoas index from pre-operative baseline to 6 months post-operative using generalized linear models. Results: A total of 33 consecutive patients were supplemented with a branched chain amino acid (BCAA) formulation. The historical cohort included 146 participants from the previous 7 years (2010-2017). 26% of patients in the historical cohort experienced wound complications compared to 30% in the supplemented group. (p=0.72) When focusing specifically on lower extremity sarcomas treated with neoadjuvant radiation therapy, 46% of patients in the supplemented group experienced wound healing complications compared to 39% in the non-supplemented group (p=0.68). BCAA supplementation was found to be protective with regards to decreasing muscle wasting with no difference in psoas index measurements throughout the study period compared to a 20% muscle loss in the historical cohort (p=0.02). Conclusion: In our limited sample size, there was no difference in wound healing complications between sarcoma patients who received postoperative BCAA supplementation compared to a historical cohort who were not supplemented. Patients who did not receive supplementation had a significant decline in post-operative psoas index following operative sarcoma removal. Level of Evidence: III.