Long-term observations of rain forest succession, tree diversity and responses to disturbance
The relationship between succession and tropical forest diversity has been much debated. A fundamental disagreement hinges on whether high local species richness is a transient successional property, albeit one that can be maintained by disturbance, or is rather a property of stable late successiona...
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| Format: | Journal Article |
| Language: | Inglés |
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2001
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| Online Access: | https://hdl.handle.net/10568/18463 |
| _version_ | 1855534416007266304 |
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| author | Sheil, Douglas |
| author_browse | Sheil, Douglas |
| author_facet | Sheil, Douglas |
| author_sort | Sheil, Douglas |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | The relationship between succession and tropical forest diversity has been much debated. A fundamental disagreement hinges on whether high local species richness is a transient successional property, albeit one that can be maintained by disturbance, or is rather a property of stable late successional communities. This paper addresses this controversy employing a series of long-term permanent sample plot data spanning seven decades. W.J. Eggeling studied the vegetation of Budongo Forest, Uganda during the 1930s and 1940s. He described a series of ten plots (1.4 and 1.86 ha) as a successional progression of forest types in which tree species numbers show a unimodal rise-and-fall over time - a pattern best known from Connell's illustration of his intermediate disturbance hypothesis. Tree communities in five of the original plots have been intermittently re-assessed over the subsequent decades. One data-series provides observations spanning 54-years from one intact ‘undisturbed' old-growth forest plot. The remaining four plots were assessed before and after controlled disturbances (tree poisoning) executed in the late 1950s and early 1960s, and the resulting data-series span c. 20 years of pre-disturbance and c.35 years of post-disturbance changes. The unimodal pattern of species-richness in the original comparative plot-series is paralled by a similar rise-and-fall in stem-densities, but rarefaction confirms that the unimodal pattern in richness also holds for fixed stem-counts. The proportion of species occurring in both large and small stem-size-classes increases across the series. As richness declines in later succession, low abundance species occur predominantly in larger stem-sizes. All time-series show a rise in species richness ranging from 12 to 177 % ha¯¹ (over 50-60 years). Each of the disturbed plots ultimately reaches greater richness than was recorded anywhere in Eggeling's original series. Contrary to expectation a small rise was also recorded in the undisturbed late successional plot (c.42 species >= 10 cm diameter ha¯¹ , rising to c.47). The lowest species density observed in the study is a 1940s record of c. 10 species >= 10 cm diameter ha¯¹ in monodominant Cynometra [Caesalpinoidae] forest and the highest record is c. 61 ha¯¹ recorded in 1992, in the youngest vegetation type monitored. These observations indicate both the volatile nature of tree-richness patterns and the limitations of simple models as aids to interpretation when confronted with real patterns of long-term change. |
| format | Journal Article |
| id | CGSpace18463 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2001 |
| publishDateRange | 2001 |
| publishDateSort | 2001 |
| record_format | dspace |
| spelling | CGSpace184632025-01-24T14:20:15Z Long-term observations of rain forest succession, tree diversity and responses to disturbance Sheil, Douglas tropical forests disturbed forests monitoring sampling species richness biodiversity dominance The relationship between succession and tropical forest diversity has been much debated. A fundamental disagreement hinges on whether high local species richness is a transient successional property, albeit one that can be maintained by disturbance, or is rather a property of stable late successional communities. This paper addresses this controversy employing a series of long-term permanent sample plot data spanning seven decades. W.J. Eggeling studied the vegetation of Budongo Forest, Uganda during the 1930s and 1940s. He described a series of ten plots (1.4 and 1.86 ha) as a successional progression of forest types in which tree species numbers show a unimodal rise-and-fall over time - a pattern best known from Connell's illustration of his intermediate disturbance hypothesis. Tree communities in five of the original plots have been intermittently re-assessed over the subsequent decades. One data-series provides observations spanning 54-years from one intact ‘undisturbed' old-growth forest plot. The remaining four plots were assessed before and after controlled disturbances (tree poisoning) executed in the late 1950s and early 1960s, and the resulting data-series span c. 20 years of pre-disturbance and c.35 years of post-disturbance changes. The unimodal pattern of species-richness in the original comparative plot-series is paralled by a similar rise-and-fall in stem-densities, but rarefaction confirms that the unimodal pattern in richness also holds for fixed stem-counts. The proportion of species occurring in both large and small stem-size-classes increases across the series. As richness declines in later succession, low abundance species occur predominantly in larger stem-sizes. All time-series show a rise in species richness ranging from 12 to 177 % ha¯¹ (over 50-60 years). Each of the disturbed plots ultimately reaches greater richness than was recorded anywhere in Eggeling's original series. Contrary to expectation a small rise was also recorded in the undisturbed late successional plot (c.42 species >= 10 cm diameter ha¯¹ , rising to c.47). The lowest species density observed in the study is a 1940s record of c. 10 species >= 10 cm diameter ha¯¹ in monodominant Cynometra [Caesalpinoidae] forest and the highest record is c. 61 ha¯¹ recorded in 1992, in the youngest vegetation type monitored. These observations indicate both the volatile nature of tree-richness patterns and the limitations of simple models as aids to interpretation when confronted with real patterns of long-term change. 2001 2012-06-04T09:06:29Z 2012-06-04T09:06:29Z Journal Article https://hdl.handle.net/10568/18463 en Sheil, D. 2001. Long-term observations of rain forest succession, tree diversity and responses to disturbance . Plant Ecology 155 :183-199. |
| spellingShingle | tropical forests disturbed forests monitoring sampling species richness biodiversity dominance Sheil, Douglas Long-term observations of rain forest succession, tree diversity and responses to disturbance |
| title | Long-term observations of rain forest succession, tree diversity and responses to disturbance |
| title_full | Long-term observations of rain forest succession, tree diversity and responses to disturbance |
| title_fullStr | Long-term observations of rain forest succession, tree diversity and responses to disturbance |
| title_full_unstemmed | Long-term observations of rain forest succession, tree diversity and responses to disturbance |
| title_short | Long-term observations of rain forest succession, tree diversity and responses to disturbance |
| title_sort | long term observations of rain forest succession tree diversity and responses to disturbance |
| topic | tropical forests disturbed forests monitoring sampling species richness biodiversity dominance |
| url | https://hdl.handle.net/10568/18463 |
| work_keys_str_mv | AT sheildouglas longtermobservationsofrainforestsuccessiontreediversityandresponsestodisturbance |