High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance
The flora of the temperate forest of southern South America highly depends on animals for pollination and seed dispersal. This resembles more tropical settings and distinguishes it from other temperate floras. This high mutualism-dependency seems paradoxical and potentially “anachronic” in view of...
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| Format: | Article |
| Language: | English |
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Asociación Argentina de Ecología
1998-12-01
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| Series: | Ecología Austral |
| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1623 |
| _version_ | 1797629045197766656 |
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| author | Marcelo A. Aizen Cecilia Ezcurra |
| author_facet | Marcelo A. Aizen Cecilia Ezcurra |
| author_sort | Marcelo A. Aizen |
| collection | DOAJ |
| description |
The flora of the temperate forest of southern South America highly depends on animals for pollination and seed dispersal. This resembles more tropical settings and distinguishes it from other temperate floras. This high mutualism-dependency seems paradoxical and potentially “anachronic” in view of this flora’s present interaction with an impoverished fauna. We analyzed the frequency of biotic pollination and seed dispersal across woody genera classified according to growth form and biogeographical affiliation. We found that genera that probably originated in warm or tropical like environments of ancient Gondwana and the Neotropics, two of the main biogeographical sources of this flora, had high incidences of biotic pollination and dispersal. The rich endemic foristic element, mostly related phylogenetically to these two foristic sources, also exhibited a high frequency of mutualism-dependency. Many endemic and Neotropical genera showed distinctive reproductive traits associated with bird pollination, a type of mutualism nearly absent in taxa with other biogeographical affiliations. This suggests that many southern South American plant taxa may have evolved novel mutualistic associations in situ, probably before the onset of present cooler climatic conditions. We propose that, despite the current relictual status of many of these genera and their associated reproductive traits, dependence on mutualists is not necessarily “anachronic” in today’s cool climate and depauperate faunal environment. Our finding that the average southernmost distribution limit is similar both for genera that depend on mutualists for either pollination or dispersal and for those that do not support this view. The steep W-E rainfall gradient created by the rising of the Andes represents a more potent ecological filter than the N-S temperature gradient, sorting out forest plant taxa according to their dependence on hummingbirds for pollination and vertebrates for dispersal. Overall, we believe that plant-animal mutualisms in the temperate forest of southern South America are still well suited interactions, because they rely on animals that are abundant and show a high degree of residency despite being represented by a low number of species. However, present human-induced elevated rates of deforestation, fragmentation and habitat degradation may be particularly threatening for mutualist-dependent plants due to low redundancy in alternative animal partners.
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| first_indexed | 2024-03-11T10:48:53Z |
| format | Article |
| id | doaj.art-3db87b98d7f448bca6adf034bfe29066 |
| institution | Directory Open Access Journal |
| issn | 0327-5477 1667-782X |
| language | English |
| last_indexed | 2024-03-11T10:48:53Z |
| publishDate | 1998-12-01 |
| publisher | Asociación Argentina de Ecología |
| record_format | Article |
| series | Ecología Austral |
| spelling | doaj.art-3db87b98d7f448bca6adf034bfe290662023-11-13T18:38:39ZengAsociación Argentina de EcologíaEcología Austral0327-54771667-782X1998-12-0182High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significanceMarcelo A. Aizen0Cecilia Ezcurra1Departamento de Ecología, Universidad Nacional del Comahue, Centro Regional Bariloche, 8400 San Carlos de Bariloche, Río Negro, Argentina.Departamento de Botánica, Universidad Nacional del Comahue, Centro Regional Bariloche, 8400 San Carlos de Bariloche, Río Negro, Argentina. The flora of the temperate forest of southern South America highly depends on animals for pollination and seed dispersal. This resembles more tropical settings and distinguishes it from other temperate floras. This high mutualism-dependency seems paradoxical and potentially “anachronic” in view of this flora’s present interaction with an impoverished fauna. We analyzed the frequency of biotic pollination and seed dispersal across woody genera classified according to growth form and biogeographical affiliation. We found that genera that probably originated in warm or tropical like environments of ancient Gondwana and the Neotropics, two of the main biogeographical sources of this flora, had high incidences of biotic pollination and dispersal. The rich endemic foristic element, mostly related phylogenetically to these two foristic sources, also exhibited a high frequency of mutualism-dependency. Many endemic and Neotropical genera showed distinctive reproductive traits associated with bird pollination, a type of mutualism nearly absent in taxa with other biogeographical affiliations. This suggests that many southern South American plant taxa may have evolved novel mutualistic associations in situ, probably before the onset of present cooler climatic conditions. We propose that, despite the current relictual status of many of these genera and their associated reproductive traits, dependence on mutualists is not necessarily “anachronic” in today’s cool climate and depauperate faunal environment. Our finding that the average southernmost distribution limit is similar both for genera that depend on mutualists for either pollination or dispersal and for those that do not support this view. The steep W-E rainfall gradient created by the rising of the Andes represents a more potent ecological filter than the N-S temperature gradient, sorting out forest plant taxa according to their dependence on hummingbirds for pollination and vertebrates for dispersal. Overall, we believe that plant-animal mutualisms in the temperate forest of southern South America are still well suited interactions, because they rely on animals that are abundant and show a high degree of residency despite being represented by a low number of species. However, present human-induced elevated rates of deforestation, fragmentation and habitat degradation may be particularly threatening for mutualist-dependent plants due to low redundancy in alternative animal partners. https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1623 |
| spellingShingle | Marcelo A. Aizen Cecilia Ezcurra High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance Ecología Austral |
| title | High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance |
| title_full | High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance |
| title_fullStr | High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance |
| title_full_unstemmed | High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance |
| title_short | High incidence of plant-animal mutualisms in the woody flora of the temperate forest of southern South America: biogeographical origin and present ecological significance |
| title_sort | high incidence of plant animal mutualisms in the woody flora of the temperate forest of southern south america biogeographical origin and present ecological significance |
| url | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1623 |
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