Demographic and population response of the threatened coral Acropora cervicornis (Scleractinia, Acroporidae) to fireworm corallivory

Introduction: The fireworm Hermodice carunculata is a widespread polychaete that can prey upon many coral species. However, few studies have examined the effect of fireworm predation on coral demographics during non-outbreak periods. Objective: To determine whether predation by H. carunculata compromised the growth, survival, and population performance of the threatened coral Acropora cervicornis. Methods: Nursery-reared coral fragments (n = 99) were fixed to the bottom of Punta Melones reef in the Island Municipality of Culebra, Puerto Rico. Predation activity and its demographic consequences on coral outplants were assessed from December 2020 to August 2022. Susceptibility to predation was compared between colonies collected directly from the reef and those originating from outside sources (e.g., coral nurseries). With the demographic data, simple size-based population matrix models were developed to 1) examine whether fireworm predation led to a significant decline in population growth rate (λ), 2) determine the demographic transition(s) that contribute the most to λ, and 3) determining the demographic transition(s) that accounted for differences in λ when comparing scenarios that considered either only predated colonies or both predated and non-predated outplants. Results: Predation increased over time, being more frequently observed in the area with the highest topographic relief and on colonies foreign to the study site. Outplants that were partially consumed grew significantly slower than non-predated colonies; however, predation did not threaten their survival. The likelihood of being attacked by the fireworm increased with branching complexity. The estimated λ for a scenario considering only predated colonies was 0.99, whereas, for a scenario where both predated and non-predated colonies were considered, λ was 0.91. Population growth, under the two scenarios, was mainly influenced by the probability of a large colony surviving and remaining at the largest size. Conclusions: Although predation can negatively impact coral growth, the relatively high survival rate of predated colonies compensates for the adverse effect. Since survival is the demographic transition that contributes most to population growth, it could be concluded that under a non-outbreak scenario, fireworm predation may not be the primary cause of A. cervicornis population decline.

Introducción: El gusano de fuego Hermodice carunculata es un poliqueto común que puede depredar muchas especies de coral. Sin embargo, pocos estudios han examinado el efecto de la depredación del gusano de fuego en la demografía de los corales durante periodos sin brotes poblacionales. Objetivo: Este estudio tuvo como objetivo determinar si la depredación por H. carunculata compromete el crecimiento, la supervivencia y el desempeño poblacional del coral amenazado Acropora cervicornis. Métodos: Fragmentos de coral criados en vivero (n = 99) se fijaron al fondo del arrecife Punta Melones en la Isla Municipio de Culebra, Puerto Rico. La actividad de depredación y sus consecuencias demográficas en los trasplantes de coral se evaluaron desde diciembre de 2020 hasta agosto de 2022. Se comparó la susceptibilidad a la depredación entre las colonias recolectadas directamente del arrecife y las que se originaron en fuentes externas (p. ej., viveros de coral). Con los datos demográficos, se desarrollaron modelos matriciales simples de población basados en el tamaño para 1) examinar si la depredación del gusano de fuego causa una disminución significativa en la tasa de crecimiento de la población (λ), 2) determinar las transiciones demográficas que más contribuyen a λ, y 3) determinar la(s) transición(es) demográfica(s) que explican las diferencias en λ al comparar escenarios que consideraron solo colonias depredadas o la combinación de colonias depredadas y no depredadas. Resultados: La depredación aumentó con el tiempo, observándose con mayor frecuencia en la zona de mayor relieve topográfico y en colonias ajenas al sitio de estudio. Los trasplantes consumidos parcialmente crecieron significativamente más lento que las colonias no depredadas; sin embargo, la depredación no amenazó su supervivencia. La probabilidad de ser atacado por el gusano de fuego aumentó con la complejidad morfológica de la colonia. El λ estimado para un escenario que consideraba solo las colonias depredadas fue de 0.99, mientras que, para un escenario en el que se consideraron tanto las colonias depredadas como las no depredadas, λ fue de 0.91. El crecimiento de la población, en ambos escenarios, estuvo influenciado principalmente por la probabilidad de que una colonia grande sobreviviera y permaneciera en el tamaño más grande. Conclusiones: Aunque la depredación puede tener un impacto negativo en el crecimiento de los corales, una tasa de supervivencia relativamente alta de las colonias depredadas compensa los efectos adversos. Dado que la supervivencia es la transición demográfica que más contribuye al crecimiento de la población, se podría concluir que, en un escenario sin brotes, la depredación por gusanos de fuego no debe ser la causa principal de la disminución de la población de A. cervicornis.

Study on the Influence of Medical Insurance Differentiation Reimbursement Policy on Patients' Flow / 中国卫生经济

Objective:The elasticity and correlation analysis were applied to analyze the influence of medical insurance differentiation reimbursement policy to guide the flow of patients,as well as the implementation of the policy of hierarchical medical system to find the problem,and then make policy recommendations for hierarchical diagnosis and health care.Methods:Yanqing District(Beijing),Mishan and Hulin(Heilongjiang) and Longxi County(Gansu) were selected as four research sites to collect each site's New Rural Cooperative Medical System(NCMS) annual data for quantitative analysis.The sample areas' NCMS annual data (from 2013 to 2015)were collected for correlation analysis and elasticity calculation by SPSS 23.0.Results:(1) Each site patients' elasticity of income and medical service price was low,the elasticity of outpatient volume-hospital service price was high.(2) Patients' behavior of choosing medical institutions to seek medical advice had low correlation with their income level and medical service prices,which had formed stable medical habits.Conclusion:Medicare differentiated reimbursement policy had a certain effect on guiding the flow of patients,but the effect was not obvious in the county.The main obstacles to implement basic initial diagnosis were the weak capacity of grassroots medical institutions and policy support was not in place.It was suggested that the health insurance differentiation reimbursement policy should be combined with the disease restriction policy,strengthen the grassroots capacity building,establish and improve the supporting policy.