Scholarlink

<p>Environmental disturbances can have severe impacts upon reef-building corals, which have flow-on effects for reef-associated fishes. Changes in taxonomic and trophic structure of fish assemblages provide valuable insight into how fishes respond to habitat disturbance; yet they do not necessarily capture changes in the ecological processes supported by fishes. Here, we analysed 20&#xa0;years of fish and coral monitoring data at two isolated oceanic reef systems with different coral disturbance histories to assess both taxonomic and functional responses of reef fishes to fluctuations in coral cover. Severe coral bleaching in 1998 caused coral cover at Scott Reefs to fall from ~ 60 to 6%, with recovery occurring over the ensuing 17&#xa0;years. Comparatively minor disturbances on Rowley Shoals reefs resulted in coral cover remaining above 25% during the same period. Drastic coral reduction at Scott Reefs was associated with reduced abundances of corallivores and an increase in grazer/detritivores. Planktivores associated with coral habitats also declined post-bleaching, while generalist carnivores and omnivores temporarily increased in abundance. Similar trends in trophic structure of fishes associated with severe coral loss at Scott Reefs were not apparent at Rowley Shoals reefs, although there was a general increase in herbivores, suggesting increases in this group at Scott Reefs are not entirely due to coral loss. The functional space occupied by fishes did not differ greatly over the 20&#xa0;years of monitoring at either Scott Reefs or Rowley Shoals. However, at Scott Reefs, functional originality was inversely correlated with <i>Acropora</i> cover, while at the Rowley Shoals, functional originality was positively related to <i>Acropora</i> cover. This disparity partially relates to differences in the range of coral cover at the two locations and shifts in how fishes occupy functional space without changing functional richness. Our results from Scott Reefs suggest that the relationship between functional originality (and functional redundancy) and total coral cover is better fitted with a nonlinear model. This implies that the impact of environmental disturbance on the function of reef fish assemblages may depend on the type of coral lost, the extent of coral loss, and subsequent recovery of coral cover following disturbance. Moreover, changes in fish assemblages and some trophic groups on relatively undisturbed Rowley Shoals reefs indicate that processes other than the dynamics of benthic composition influence fish populations and that fishes will be affected by both density-dependent and independent processes.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Taxonomic, trophic and functional change of fishes on oceanic coral reefs with contrasting coral disturbance histories

  • 期刊论文

  • 发表日期：

    2025年11月10日

查看全文
  • Matthew J. Birt,
  • Shaun Wilson,
  • Defne Sahin,
  • Nicole Ryan,
  • Martial Depczynski,
  • Conrad W. Speed,
  • Michael J. Travers,
  • James Gilmour

摘要

Environmental disturbances can have severe impacts upon reef-building corals, which have flow-on effects for reef-associated fishes. Changes in taxonomic and trophic structure of fish assemblages provide valuable insight into how fishes respond to habitat disturbance; yet they do not necessarily capture changes in the ecological processes supported by fishes. Here, we analysed 20 years of fish and coral monitoring data at two isolated oceanic reef systems with different coral disturbance histories to assess both taxonomic and functional responses of reef fishes to fluctuations in coral cover. Severe coral bleaching in 1998 caused coral cover at Scott Reefs to fall from ~ 60 to 6%, with recovery occurring over the ensuing 17 years. Comparatively minor disturbances on Rowley Shoals reefs resulted in coral cover remaining above 25% during the same period. Drastic coral reduction at Scott Reefs was associated with reduced abundances of corallivores and an increase in grazer/detritivores. Planktivores associated with coral habitats also declined post-bleaching, while generalist carnivores and omnivores temporarily increased in abundance. Similar trends in trophic structure of fishes associated with severe coral loss at Scott Reefs were not apparent at Rowley Shoals reefs, although there was a general increase in herbivores, suggesting increases in this group at Scott Reefs are not entirely due to coral loss. The functional space occupied by fishes did not differ greatly over the 20 years of monitoring at either Scott Reefs or Rowley Shoals. However, at Scott Reefs, functional originality was inversely correlated with Acropora cover, while at the Rowley Shoals, functional originality was positively related to Acropora cover. This disparity partially relates to differences in the range of coral cover at the two locations and shifts in how fishes occupy functional space without changing functional richness. Our results from Scott Reefs suggest that the relationship between functional originality (and functional redundancy) and total coral cover is better fitted with a nonlinear model. This implies that the impact of environmental disturbance on the function of reef fish assemblages may depend on the type of coral lost, the extent of coral loss, and subsequent recovery of coral cover following disturbance. Moreover, changes in fish assemblages and some trophic groups on relatively undisturbed Rowley Shoals reefs indicate that processes other than the dynamics of benthic composition influence fish populations and that fishes will be affected by both density-dependent and independent processes.