| Literature DB >> 21152062 |
Andrew B Johnson1, Kevin Winker.
Abstract
Populations in fragmented ecosystems risk extirpation through natural disasters, which must be endured rather than avoided. Managing communities for resilience is thus critical, but details are sketchy about the capacity for resilience and its associated properties in vertebrate communities. We studied short-term resilience in a community of individually marked birds, following this community through the catastrophic destruction of its forest habitat by Hurricane Iris in Belize, Central America. We sampled for 58 d immediately before the storm, 28 d beginning 11 d after Hurricane Iris, and for 69 d approximately one year later. Our data showed that the initial capacity for resilience was strong. Many banded individuals remained after the storm, although lower post-hurricane recapture rates revealed increased turnover among individuals. Changes occurred in community dynamics and in abundances among species and guilds. Survivors and immigrants both were critical components of resilience, but in a heterogeneous, species-specific manner. Delayed effects, including higher fat storage and increased species losses, were evident one year later.Entities:
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Year: 2010 PMID: 21152062 PMCID: PMC2994923 DOI: 10.1371/journal.pone.0015109
Source DB: PubMed Journal: PLoS One ISSN: 1932-6203 Impact factor: 3.240
Figure 1Habitat changes to lowland forest wrought by Hurricane Iris, which struck on 8 October 2001.
Top left: A net lane during the Pre-Iris sampling period. Note shade and lush vegetation. Top right: A net lane during the Post-I sampling period. Note lack of shade and extensive damage to vegetation. Bottom: Typical damage to the lowland forest landscape caused by Hurricane Iris near Big Falls, Toledo District, Belize.
Figure 2Changes in the avian community after Hurricane Iris.
X-axis is number of days from beginning of study (11 August 2001), and sampling periods are highlighted (pale blue). A small proportion of species that were regular members of the Pre-Iris community were lost by Post-I, but these losses increased by Post-II (green). Species diversity (Shannon Index; blue) showed a significant decrease by Post-I and was still significantly lower during Post-II. Mean capture rate (captures per net h, an index of abundance) among non-granivore species (orange) increased significantly during Post-I, then decreased during Post-II to a level significantly below the Pre-Iris level. Mean fat score (red) among non-granivores increased significantly during Post-I and stayed above Pre-Iris levels during Post-II.
Figure 3Species accumulation curves during the three sampling periods to contrast changes in community structure.
The Post-I species accumulation curve had a much higher intercept than the Pre-Iris curve, but their shapes were the same. The Post-II curve was significantly different from both the Pre-Iris and Post-I curves, climbing more steeply and flattening more abruptly than the other two.
Figure 4Guild-level changes due to Hurricane Iris.
All guilds except Nectarivores showed a significant increase in Post-I. All guilds except Granivores had significant decreases to below Pre-Iris abundance levels by Post-II (see Table S2).
Some responses of vertebrate communities to catastrophic disturbances revealed by this and other studies.
| Response | Basis |
| 1) Community dynamics are altered: species diversity and species accumulation curves change. |
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| 2) Species are lost, but at a smaller magnitude than the degree of habitat alteration. | Species losses in birds |
| 3) Abundances fluctuate at the community level and among species and species groups. Carrying capacity is lowered for some species. Some species preferring changed habitat become abundant. | Abundance changes in birds, frogs, lizards, and mammals |
| 4) “Determined residents”: Strong individual site fidelity occurs through storm and continues long afterwards despite drastic habitat changes. | In humans |
| 5) “Stirring effect” occurs among individuals: Individual mobility increases at the community scale. | Changed recapture rates (this study);suggested at population level by regional post-disaster shift in habitat use in lizards and birds |
| 6) Both survivors and immigrants comprise components of resilience in post-disaster populations, but in a heterogeneous, species- specific manner. Immigrants include new species. | This study; new species as colonists in birds [ |
| 7) Heavily damaged habitat can provide survivors and immigrants. | This study ( |
| 8) Delayed effects occur: Recolonization takes time, and delayed species losses occur. | In birds and lizards [ |
| 9) Energetic regime shift can occur: Individual fat storage increases and remains higher one year later. | Fat storage increase in birds [ |
| 10) Some formerly common or regular community members now present in very low densities. | This study ( |