NGOs are important civil actors in societies' emergency and disaster responses, and they come together on social media to identify prominent issues and coordinate issue responses. This research explores how U.S. NGO form topic-driven communities on social media to discuss and build representational strategic networks around issues related to the COVID-19 pandemic. Drawing from Issue Niche Theory, we examined how NGOs' networks and discourse evolved before and after the general public paid great attention to the COVID-19 issue and how such patterns changed across the whole issue niche and sub-issue niches. We analyzed the evolution of Twitter-based networks and discourse of 2,588 NGOs in the first five months of the COVID-19 outbreak in the United States. Our analysis revealed important factors that shape tie formation patterns in the NGOs' communities in this novel issue niche. The findings show that NGOs’ discourses help to orient the organizational community to identify most salient issues. Finally, changes in the discourse patterns reflected changes in the communication networks in the NGO community.

非政府组织是社会应急和灾难响应中的重要民间行为者，他们在社交媒体上聚集在一起，确定突出问题并协调问题响应。这项研究探讨了美国非政府组织如何在社交媒体上形成主题驱动的社区，以围绕与 COVID-19 大流行相关的问题讨论和建立代表性战略网络。借鉴问题利基理论，我们研究了非政府组织的网络和话语在公众高度关注 COVID-19 问题之前和之后如何演变，以及这种模式如何在整个问题利基和子问题利基中发生变化。我们分析了 2,588 个非政府组织在美国 COVID-19 爆发的前五个月中基于 Twitter 的网络和话语的演变。我们的分析揭示了在这个新问题利基市场中影响非政府组织社区关系形成模式的重要因素。调查结果表明，非政府组织的话语有助于引导组织社区确定最突出的问题。最后，话语模式的变化反映了非政府组织社区中沟通网络的变化。