Many nonprofit emergency service organizations rely heavily on volunteers. With the recent decline in volunteer numbers and the associated economic cost, it is important for nonprofit organizations to develop strategies aimed at improving volunteer retention. To this end, we applied job demands-resources theory to examine how volunteer demands and resources explain volunteers' well-being (i.e., exhaustion and engagement) and consequently, retention and mental health (i.e., depressive symptoms). Specifically, we hypothesized that: (1) exhaustion mediates the positive relationship between demands and depressive symptoms, and the negative relationship between demands and retention; (2) engagement mediates the positive relationship between resources and retention; (3) resources buffer the positive relationship between demands and exhaustion; and (4) demands boost the positive relationship between resources and engagement. Volunteer firefighters (N = 126) were asked to complete a self-report questionnaire twice over a 1-year period. Results showed that increases in engagement mediated the positive relationship between resources and retention over time. Contrary to expectations, volunteer resources boosted the positive relationship between volunteer demands and increases in exhaustion. Namely, demands related positively with exhaustion particularly when resources were high (instead of low). Collectively, the study results have important theoretical implications since they suggest that demands do not always have long-term, unfavorable consequences for volunteer firefighters. In contrast, resources enhance volunteer engagement and consequently, promote retention in the long run. Therefore, it is important for volunteer organizations to provide relevant resources to their members to keep them engaged and enhance their willingness to remain in the force.

中文翻译：

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对非营利部门志愿消防员工作需求资源理论的纵向调查

许多非营利紧急服务组织严重依赖志愿者。随着最近志愿者数量和相关经济成本的下降，非营利组织制定旨在提高志愿者保留率的战略非常重要。为此，我们应用工作需求-资源理论来研究志愿者的需求和资源如何解释志愿者的幸福感（即疲惫和投入），从而解释志愿者的保留和心理健康（即抑郁症状）。具体来说，我们假设：（1）疲惫介导需求与抑郁症状之间的正相关关系以及需求与保留之间的负相关关系；(2)参与度调节资源和保留之间的正向关系；(3)资源缓冲需求与耗尽之间的正相关关系；(4)需求促进资源与参与度之间的正向关系。志愿消防员（N  = 126）被要求在一年内完成两次自我报告调查问卷。结果表明，随着时间的推移，参与度的增加调节了资源和保留之间的正相关关系。与预期相反，志愿者资源促进了志愿者需求与疲惫增加之间的正相关关系。也就是说，需求与耗尽呈正相关，特别是当资源高（而不是低）时。总的来说，研究结果具有重要的理论意义，因为它们表明需求并不总是对志愿消防员产生长期的、不利的后果。相比之下，资源可以提高志愿者的参与度，从而从长远来看提高志愿者的保留率。因此，志愿者组织必须为其成员提供相关资源，以保持他们的参与并增强他们留在部队的意愿。