Seabird islands take mere decades to recover following rat eradication

Abstract

Abstract. Islands house a majority of the world's biodiversity and are thus critical for biodiversity conservation. Seabird nesting colonies provide nutrients that are integral to maintain island biodiversity and ecosystem function. Invasive rats destroy seabird colonies and thus the island ecosystems that depend on seabird-derived nutrients. After rat eradication, it is unclear how long ecosystem recovery may take, although some speculate on the order of centuries. I looked at ecosystem recovery along a chronosequence of islands that had 12-22 years to recover following rat eradication. I show that soil, plant, and spider marine-derived nitrogen levels and C:N ratios take mere decades to recover even after centuries-long rat invasion. Moreover, active seabird restoration could speed recovery even further, giving much hope to quickly conserve many endemic species on islands worldwide.

Recovery of marine animal populations and ecosystems

“…In Kenya, fishers' catches and income strongly increased after the establishment of closed areas combined with beach seine bans [9,49]. In some cases, marine recoveries can even benefit terrestrial ecosystems, as in the recovery of seabird colonies that enhance biodiversity and functions of island ecosystems by supplying essential marine-derived nitrogen (Figure 3d) [17]. Only a few marine ecosystems, such as Monterey Bay, California [70], have so far shown strong recovery in their structure, function and services over a large area.…”

“…Similarly, many coastal habitats, including wetlands, seagrass beds, mangrove and kelp forests, and oyster and coral reefs, have been severely reduced or degraded [2][3][4]6], yet partial recovery has been achieved in some regions in response to protection and pollution controls [3,13]. Restoration attempts at an ecosystem level have often been followed by the return and recovery of former species assemblages and ecosystem functions [13][14][15][16][17], but some ecosystems have remained in an altered state [18]. Such successes could serve as important guides for efforts to prevent further biodiversity loss and enhance future recoveries.…”

Invasive House (Rattus Rattus) and Brown Rats (Rattus Norvegicus) Threaten the Viability of Red-Billed Tropicbird (Phaethon Aethereus) in Abrolhos National Park, Brazil

“…Of these, eradication is the preferable and most effective management option from an ecological standpoint [60]. At least 1,224 successful eradications of invasive species have now been completed on 808 islands around the world [61] and there is good evidence that seabird populations can rapidly recover after the rodents have been removed [62].…”

Spatio-temporal changes in density and distribution of burrow-nesting seabird colonies after rat eradication

“…We found that mean burrow density on restored islands was less than half (<0.1 burrow/m 2 ) that on the never-invaded Ruamaahuanui (>0.2 burrow/m 2 ). Thus, although increases in the number of burrows after rat eradication may seem rapid, burrow densities on restored islands have probably not yet reached a level where seabird-dominated ecosystem functioning is possible (Jones 2010b).…”