Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures
Abstract Much of deforested Amazonia is dominated by pastures planted with exotic Urochloa (syn Brachiaria) grass, containing interspersed, ruderal Babassu palm (Attalea speciosa). This two‐species system offers the opportunity to investigate how two very competitive species interact. We investigate...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2023-11-01
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| Series: | Ecosphere |
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| Online Access: | https://doi.org/10.1002/ecs2.4687 |
| _version_ | 1797448848093741056 |
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| author | André Brenner deAlencar Pageú Odenilson deDeus Ribeiro Lima Daniel Cutrim Diniz Luciana Sousa daSilva Maria Elisabeth Detert Christoph Gehring |
| author_facet | André Brenner deAlencar Pageú Odenilson deDeus Ribeiro Lima Daniel Cutrim Diniz Luciana Sousa daSilva Maria Elisabeth Detert Christoph Gehring |
| author_sort | André Brenner deAlencar Pageú |
| collection | DOAJ |
| description | Abstract Much of deforested Amazonia is dominated by pastures planted with exotic Urochloa (syn Brachiaria) grass, containing interspersed, ruderal Babassu palm (Attalea speciosa). This two‐species system offers the opportunity to investigate how two very competitive species interact. We investigated three monospecific Urochloa pastures containing dispersed Babassu palm clusters in the eastern periphery of Amazonia. We mapped 0‐ to 50‐cm Babassu and Urochloa root profiles at three distances representing contrasting relative dominance: “within clusters” (0.4–0.6 m from adult palm, Babassu‐dominated), “close” (2.5–4.0 m), and “far” (>8.0–10.0 m, Urochloa‐dominated). Total Babassu root share count was 76.0% within Babassu clusters, as opposed to Urochloa root share count (80.0%) far from clusters, confirming our experimental dominance gradient. Babassu and Urochloa root diameter composition differed strongly, whereas 44.6% of all Babassu roots were mid‐diameter or coarse; 83.0% of all Urochloa roots were fine graminoid. Vertical root profiles likewise differed: Babassu coarse and mid‐diameter roots concentrated within clusters at 20–50 cm depth, well protected against disturbance, though Babassu mid‐diameter roots did extend up to 10 m, indicating active foraging at long distances. By contrast, Urochloa mid‐diameter and coarse roots concentrated in the topsoil (70.4% in top 20 cm). Notably, 45.0% of all Urochloa fine roots but only 29.3% of deeper rooting Babassu concentrated in the top 0–10 cm. Both Urochloa mid‐diameter (R = 0.49) and fine roots (R = 0.40) correlated positively with Urochloa aboveground biomass. Fine‐root fine‐scale variability was high, with high‐density hotspots of both species in the topsoil. Babassu vertical root profiles were unaffected by the degree of interspecific competitive confrontation, whereas Urochloa fine roots were significantly shallower within than outside of Babassu clusters. Though differing Babassu and Urochloa vertical root profiles do support the notion of niche expansion caused by Babassu clusters within the vast Urochloa pastures throughout Amazonia, we also find a strong horizontal and vertical niche overlap with no indication of fine‐scale root segregation, indicating direct competition between both species, possibly in a dynamic state of “mutual invasability.” In practical terms, our findings call for the diversification of Amazonian pastures beyond this two‐species system in order to increase productivity and ecological efficiency. |
| first_indexed | 2024-03-09T14:16:20Z |
| format | Article |
| id | doaj.art-07d3cb288fe0419e82ce72ef2b84b304 |
| institution | Directory Open Access Journal |
| issn | 2150-8925 |
| language | English |
| last_indexed | 2024-03-09T14:16:20Z |
| publishDate | 2023-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | Ecosphere |
| spelling | doaj.art-07d3cb288fe0419e82ce72ef2b84b3042023-11-29T00:24:33ZengWileyEcosphere2150-89252023-11-011411n/an/a10.1002/ecs2.4687Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pasturesAndré Brenner deAlencar Pageú0Odenilson deDeus Ribeiro Lima1Daniel Cutrim Diniz2Luciana Sousa daSilva3Maria Elisabeth Detert4Christoph Gehring5Post‐Graduate Program in Agroecology Maranhão State University São Luís BrazilPost‐Graduate Program in Agroecology Maranhão State University São Luís BrazilPost‐Graduate Program in Agroecology Maranhão State University São Luís BrazilPost‐Graduate Program in Agroecology Maranhão State University São Luís BrazilNGO ‘Education and Environment’ – EMA Pirapemas BrazilPost‐Graduate Program in Agroecology Maranhão State University São Luís BrazilAbstract Much of deforested Amazonia is dominated by pastures planted with exotic Urochloa (syn Brachiaria) grass, containing interspersed, ruderal Babassu palm (Attalea speciosa). This two‐species system offers the opportunity to investigate how two very competitive species interact. We investigated three monospecific Urochloa pastures containing dispersed Babassu palm clusters in the eastern periphery of Amazonia. We mapped 0‐ to 50‐cm Babassu and Urochloa root profiles at three distances representing contrasting relative dominance: “within clusters” (0.4–0.6 m from adult palm, Babassu‐dominated), “close” (2.5–4.0 m), and “far” (>8.0–10.0 m, Urochloa‐dominated). Total Babassu root share count was 76.0% within Babassu clusters, as opposed to Urochloa root share count (80.0%) far from clusters, confirming our experimental dominance gradient. Babassu and Urochloa root diameter composition differed strongly, whereas 44.6% of all Babassu roots were mid‐diameter or coarse; 83.0% of all Urochloa roots were fine graminoid. Vertical root profiles likewise differed: Babassu coarse and mid‐diameter roots concentrated within clusters at 20–50 cm depth, well protected against disturbance, though Babassu mid‐diameter roots did extend up to 10 m, indicating active foraging at long distances. By contrast, Urochloa mid‐diameter and coarse roots concentrated in the topsoil (70.4% in top 20 cm). Notably, 45.0% of all Urochloa fine roots but only 29.3% of deeper rooting Babassu concentrated in the top 0–10 cm. Both Urochloa mid‐diameter (R = 0.49) and fine roots (R = 0.40) correlated positively with Urochloa aboveground biomass. Fine‐root fine‐scale variability was high, with high‐density hotspots of both species in the topsoil. Babassu vertical root profiles were unaffected by the degree of interspecific competitive confrontation, whereas Urochloa fine roots were significantly shallower within than outside of Babassu clusters. Though differing Babassu and Urochloa vertical root profiles do support the notion of niche expansion caused by Babassu clusters within the vast Urochloa pastures throughout Amazonia, we also find a strong horizontal and vertical niche overlap with no indication of fine‐scale root segregation, indicating direct competition between both species, possibly in a dynamic state of “mutual invasability.” In practical terms, our findings call for the diversification of Amazonian pastures beyond this two‐species system in order to increase productivity and ecological efficiency.https://doi.org/10.1002/ecs2.4687Attalea speciosaBrachiariadominance effectsniche expansionpalisade grassroot competition |
| spellingShingle | André Brenner deAlencar Pageú Odenilson deDeus Ribeiro Lima Daniel Cutrim Diniz Luciana Sousa daSilva Maria Elisabeth Detert Christoph Gehring Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures Ecosphere Attalea speciosa Brachiaria dominance effects niche expansion palisade grass root competition |
| title | Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures |
| title_full | Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures |
| title_fullStr | Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures |
| title_full_unstemmed | Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures |
| title_short | Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures |
| title_sort | belowground competition and niche partitioning between the babassu palm and urochloa grass in eastern amazonian pastures |
| topic | Attalea speciosa Brachiaria dominance effects niche expansion palisade grass root competition |
| url | https://doi.org/10.1002/ecs2.4687 |
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