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Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years
Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of north...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Blackwell Publishing Ltd
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3297176/ https://www.ncbi.nlm.nih.gov/pubmed/22408724 http://dx.doi.org/10.1002/ece3.70 |
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author | Tng, David Y P Murphy, Brett P Weber, Ellen Sanders, Gregor Williamson, Grant J Kemp, Jeanette Bowman, David M J S |
author_facet | Tng, David Y P Murphy, Brett P Weber, Ellen Sanders, Gregor Williamson, Grant J Kemp, Jeanette Bowman, David M J S |
author_sort | Tng, David Y P |
collection | PubMed |
description | Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO(2) as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire disturbance. |
format | Online Article Text |
id | pubmed-3297176 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Blackwell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-32971762012-03-09 Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years Tng, David Y P Murphy, Brett P Weber, Ellen Sanders, Gregor Williamson, Grant J Kemp, Jeanette Bowman, David M J S Ecol Evol Original Research Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO(2) as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire disturbance. Blackwell Publishing Ltd 2012-01 /pmc/articles/PMC3297176/ /pubmed/22408724 http://dx.doi.org/10.1002/ece3.70 Text en © 2011 The Authors. Published by Blackwell Publishing Ltd. http://creativecommons.org/licenses/by/2.5/ This is an open access article under the terms of the Creative Commons Attribution Non Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
spellingShingle | Original Research Tng, David Y P Murphy, Brett P Weber, Ellen Sanders, Gregor Williamson, Grant J Kemp, Jeanette Bowman, David M J S Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
title | Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
title_full | Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
title_fullStr | Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
title_full_unstemmed | Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
title_short | Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
title_sort | humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3297176/ https://www.ncbi.nlm.nih.gov/pubmed/22408724 http://dx.doi.org/10.1002/ece3.70 |
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