El papel de aves no nectarívoras como polinizadoras de Anarthrophyllum desideratum en la estepa patagónica: una aproximación geográfica

• DOI: 10.25260/ea.17.27.3.0.476
• Publication Date: 2018-01-04T14:05:59Z
• Authors: Valeria Paiaro; Andrea A. Cocucci; Gabriel E. Oliva; Alicia N. Sérsic
• Keywords: Pollinator; Polinizadores; Anarthrophyllum desideratum; Factores climáticos; Climatic factors; Plant Science; 02 engineering and technology; BREEDING SYSTEM; CLIMATIC FACTORS; Estructura geográfica; Agricultural and Biological Sciences; Biodiversity Conservation and Ecosystem Management; Range (aeronautics); Sociology; GE1-350; Pollination; Geographical structure; QH540-549.5; Pájaros; Phytochemical Analysis; Ecology; Geography; Pollinators; BIRD ASSEMBLAGE COMPOSITION; FACTORES CLIMATICOS; Life Sciences; Diversity and Applications of Cyperus Species; Nectar; FOS: Sociology; Physical Sciences; ESTRUCTURA GEOGRAFICA; Passerines; Animales Utiles; Pollen; Polinización; Impact of Pollinator Decline on Ecosystems and Agriculture; Aves; Breeding system; Sistema reproductivo; PASSERINES; Composite material; ZONOTRICHIA CAPENSIS; Composición del ensamble de aves; Population; 0207 environmental engineering; VISITANTES FLORALES; SISTEMA REPRODUCTIVO; FLORAL VISITORS; Bird assemblage composition; Passerine; Birds; COMPOSICION DEL ENSAMBLE DE AVES; PASERIFORMES; Floral visitors; Paseriformes; Phrygilus gayi; Hummingbird; PHRYGILUS GAYI; Biology; Ecology, Evolution, Behavior and Systematics; Nature and Landscape Conservation; Demography; Estepa Patagónica; 15. Life on land; Materials science; Zonotrichia capensis; Environmental sciences; GEOGRAPHICAL STRUCTURE; FOS: Biological sciences; Environmental Science; Useful Animals; Visitantes florales

The endemic shrub Anarthrophyllum desideratum appears to be the only ornithophilous plant offering nectar as a reward in the extensive Patagonian steppe. The identity of its floral visitor assemblage and to what extent this species depends on bird pollination for sexual reproduction is yet unknown. A. desideratum's vast distribution includes climatic gradients, which may promote geographical shifts in its floral visitors. The aims of this study were to determine the species dependence on pollinators to set fruits, to identify its floral visitor assemblages, to document possible geographical and environmental variation of these assemblages across the species range and to assess their temporal constancy. We conducted different pollination treatments in various populations to assess the species breeding system. Floral visitors were identified in 18 populations distributed along the entire species range and their visitation frequencies were quantified over three flowering periods. We found that the species is self-compatible and that floral visitors do not contribute to fruit sets in two marginal populations. Fruit set of open pollinated plants significantly differed among populations, which suggests that the species dependence on pollinators varies among sites. Eight species of non-exclusively nectarivorous birds, mostly passerines, were observed visiting flowers arranged in different assemblages across the species range. Population differences in the proportion of visits by the two most abundant bird species remained constant over time. Geographical differences of bird assemblages were not spatially structured and were weakly associated with climate of the flowering period, suggesting that climatic gradients would not be important as drivers of the geographical variation in A. desideratum's floral visitors. Our results indicate that non-exclusively nectarivorous birds visit flowers of A. desideratum, revealing for first time the facultative nectarivory behaviour of these bird species in the Patagonian steppe. The potential role of such bird visitors as pollinators of A. desideratum appears to vary geographically.DOI: https://doi.org/10.25260/EA.17.27.3.0.476<br/>يبدو أن الشجيرة المتوطنة Anarthrophyllum desideratum هي النبات الوحيد المحب للطير الذي يقدم الرحيق كمكافأة في سهوب باتاغونيا الواسعة. هوية تجمع زوار الأزهار وإلى أي مدى يعتمد هذا النوع على تلقيح الطيور للتكاثر الجنسي غير معروف حتى الآن. أ. يشمل التوزيع الواسع لـ desideratum التدرجات المناخية، والتي قد تعزز التحولات الجغرافية في زوار الأزهار. كانت أهداف هذه الدراسة هي تحديد اعتماد الأنواع على الملقحات لوضع الثمار، وتحديد تجمعات زوار الأزهار، وتوثيق التباين الجغرافي والبيئي المحتمل لهذه التجمعات عبر نطاق الأنواع وتقييم ثباتها الزمني. أجرينا علاجات مختلفة للتلقيح في مجموعات سكانية مختلفة لتقييم نظام تربية الأنواع. تم تحديد زوار الأزهار في 18 مجموعة موزعة على طول نطاق الأنواع بأكمله وتم تحديد ترددات زيارتهم على مدى ثلاث فترات ازدهار. وجدنا أن هذا النوع متوافق ذاتيًا وأن زوار الأزهار لا يساهمون في مجموعات الفاكهة في مجموعتين هامشيتين. اختلفت مجموعة الفاكهة من النباتات الملقحة المفتوحة اختلافًا كبيرًا بين المجموعات، مما يشير إلى أن اعتماد الأنواع على الملقحات يختلف بين المواقع. لوحظت ثمانية أنواع من الطيور آكلة الرحيق غير الحصرية، معظمها من الجواثم، تزور الزهور المرتبة في تجمعات مختلفة عبر نطاق الأنواع. ظلت الاختلافات السكانية في نسبة زيارات أكثر نوعين من الطيور وفرة ثابتة بمرور الوقت. لم تكن الاختلافات الجغرافية لتجمعات الطيور منظمة مكانيًا وكانت مرتبطة بشكل ضعيف بمناخ فترة الإزهار، مما يشير إلى أن التدرجات المناخية لن تكون مهمة كمحركات للاختلاف الجغرافي في زوار أزهار A. desideratum. تشير نتائجنا إلى أن الطيور آكلة الرحيق غير الحصرية تزور أزهار A. desideratum، مما يكشف لأول مرة عن السلوك الرحيق الاختياري لهذه الأنواع من الطيور في سهوب باتاغونيا. يبدو أن الدور المحتمل لزوار الطيور مثل ملقحات A. desideratum يختلف جغرافيًا. DOI: https://doi.org/10.25260/EA.17.27.3.0.476<br/>The endmic shrub Anarthrophyllum desideratum appears to be the only ornithophilous plant offering nectar as reward in the extensive Patagonian steppe. The identity of its floral visitor assemblage and to what extent this species depends on bird pollination for sexual reproduction is yet unknown. A. desideratum's vast distribution includes climatic gradients, which may promote geographical shifts in its floral visitors. The aims of this study were to determiner the species dependence on pollinators to set fruits, to identify its floral visitor assemblages, to document possible geographical and environmental variation of these assemblages across the species range and to assess their temporal constancy. We conducted different pollination treatments in several populations to assess the species breeding system. Floral visitors were identified in 18 populations distributed along the entire species range and their visitation frequencies were quantified over three flowering periods. We found that the species is self-compatible and that floral visitors do not contribute to fruit set in two marginal populations. Fruit set of open pollinated plants significantly differed among populations, which suggests that the species dependence on pollinators varies among sites. Eight species of non-exclusively nectarivorous birds, mostly passerine, were observd visiting flowers arranged in different assemblages across the species range. Population differences in the proportion of visits by the two most abundant bird species remained constant over time. Geographical differences of bird assemblages were not spatially structured and were weakly associated with climate of the flowering period, suggesting that climatic gradients would not be important as drivers of the geographical variation in A. desideratum's floral visitors. Our results indicate that non-exclusively nectarivorous birds visit flowers of A. desideratum, revealing for first time the facultative nectarivory behaviour of these bird species in the Patagonian steppe. The potential role of such bird visitors as pollinators of A. desideratum appears to vary geographically.DOI : https://doi.org/10.25260/EA.17.27.3.0.476<br/>The endemic shrub Anarthrophyllum desideratum appears to be the only ornithophilous plant offering nectar as reward in the extensive Patagonian steppe. The identity of its floral visitor assemblage and to what extent this species depends on bird pollination for sexual reproduction is yet unknown. A. desideratum's vast distribution includes climatic gradients, which may promote geographical shifts in its floral visitors. The aims of this study were to determine the species dependence on pollinators to set fruits, to identify its floral visitor assemblages, to document possible geographical and environmental variation of these assemblages across the species range and to assess their temporal constancy. We conducted different pollination treatments in several populations to assess the species breeding system. Floral visitors were identified in 18 populations distributed along the entire species range and their visitation frequencies were quantified over three flowering periods. We found that the species is self-compatible and that floral visitors do not contribute to fruit set in two marginal populations. Fruit set of open pollinated plants significantly differed among populations, which suggests that the species dependence on pollinators varies among sites. Eight species of non-exclusively nectarivorous birds, mostly passerine, were observed visiting flowers arranged in different assemblages across the species range. Population differences in the proportion of visits by the two most abundant bird species remained constant over time. Geographical differences of bird assemblages were not spatially structured and were weakly associated with climate of the flowering period, suggesting that climatic gradients would not be important as drivers of the geographical variation in A. desideratum's floral visitors. Our results indicate that non-exclusively nectarivorous birds visit flowers of A. desideratum, revealing for first time the facultative nectarivory behaviour of these bird species in the Patagonian steppe. The potential role of such bird visitors as pollinators of A. desideratum appears to vary geographically.DOI: https://doi.org/10.25260/EA.17.27.3.0.476<br/>