Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon
Background Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods We used...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2014-11-01
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| Series: | Forest Ecosystems |
| Online Access: | https://forestecosyst.springeropen.com/articles/10.1186/s40663-014-0022-3 |
| _version_ | 1797969161505210368 |
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| author | David Kenfack George B Chuyong Richard Condit Sabrina E Russo Duncan W Thomas |
| author_facet | David Kenfack George B Chuyong Richard Condit Sabrina E Russo Duncan W Thomas |
| author_sort | David Kenfack |
| collection | DOAJ |
| description | Background
Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography.
Methods
We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat (‘residents’) should outperform species that are specialists of other habitats (‘foreigners’). Second, across different topographic habitats, species should perform best in the habitat on which they specialize (‘home’) compared to other habitats (‘away’). Species’ performance was estimated using growth and mortality rates.
Results
In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat.
Conclusions
We reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees ≥1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval. |
| first_indexed | 2024-04-11T02:56:44Z |
| format | Article |
| id | doaj.art-d728cdb9dfb54ba8809ff03b5bdd55e0 |
| institution | Directory Open Access Journal |
| issn | 2095-6355 2197-5620 |
| language | English |
| last_indexed | 2024-04-11T02:56:44Z |
| publishDate | 2014-11-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Forest Ecosystems |
| spelling | doaj.art-d728cdb9dfb54ba8809ff03b5bdd55e02023-01-02T14:59:18ZengKeAi Communications Co., Ltd.Forest Ecosystems2095-63552197-56202014-11-01110.1186/s40663-014-0022-3Demographic variation and habitat specialization of tree species in a diverse tropical forest of CameroonDavid Kenfack0George B Chuyong1Richard Condit2Sabrina E Russo3Duncan W Thomas4Center for Tropical Forest Science - ForestGEO, Botany Department, Smithsonian Tropical Research InstituteDepartment of Botany and Plant Physiology, University of BueaCenter for Tropical Forest Science, Smithsonian Tropical Research InstituteSchool of Biological Sciences, University of NebraskaDepartment of Biological Sciences, Washington State UniversityBackground Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat (‘residents’) should outperform species that are specialists of other habitats (‘foreigners’). Second, across different topographic habitats, species should perform best in the habitat on which they specialize (‘home’) compared to other habitats (‘away’). Species’ performance was estimated using growth and mortality rates. Results In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat. Conclusions We reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees ≥1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval.https://forestecosyst.springeropen.com/articles/10.1186/s40663-014-0022-3 |
| spellingShingle | David Kenfack George B Chuyong Richard Condit Sabrina E Russo Duncan W Thomas Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon Forest Ecosystems |
| title | Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon |
| title_full | Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon |
| title_fullStr | Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon |
| title_full_unstemmed | Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon |
| title_short | Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon |
| title_sort | demographic variation and habitat specialization of tree species in a diverse tropical forest of cameroon |
| url | https://forestecosyst.springeropen.com/articles/10.1186/s40663-014-0022-3 |
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