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Bartomeus bes sfe_lille

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BES-Sfe conference in Lille.

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Bartomeus bes sfe_lille

  1. 1. An empirical evaluation of the role of network structure for community stability Ignasi Bartomeus www.bartomeuslab.com nacho.bartomeus@gmail.com @ibartomeus
  2. 2. WHY?
  3. 3. 1) nestedness confer stability in mutualistic networks
  4. 4. Thebault and Fontaine 2006. Science, Lever et al. 2014 Ecol. Let.
  5. 5. 2) Species contributing most to nestedness are more likely to go extinct
  6. 6. Saavedra et al. 2011 Nature; 2013 Nature comm.
  7. 7. Confront expectations with data!
  8. 8. How?
  9. 9. ? ? ? ? ? ? ? ? ? ? 300 to 3,000 m radius a b ? ? Figure 3 Schematic showing the two study designs contrasted in this review. (a) Design focused on surrounding landscape cover. Sampling is generally done within a fixed habitat type. In the most common design, sites vary in the proportion of surrounding land cover composed of specific habitat types such as forest (dark green) or agriculture ( yellow). The radius at which landscape cover is assessed varies across studies but is typically between 300 and 3,000 m. Other designs, which we include in this category, vary either the linear distance to the nearest habitat patch or the area of the habitat patch. (b) Design focused on local land-use type.These studies compare pollinator communities among different habitat types. The surrounding landscape cover and the spatial extent of the habitat type where pollinators are sampled are generally not reported. Figure 4)]. Bees and butterflies both show strong negative responses to land-use change in extreme systems, butmoremixed responses inmoderate systems (Supplemental Tables 2 and 3). Extreme land use causes a strong decrease in abundance and/or richness (e.g., Aizen & Feinsinger 1994, Koh & Sodhi 2004, Kremen et al. 2002, Ockinger & Smith 2006), whereas studies in moderately anthropogenic landscapes find more varied responses (e.g., Bartomeus et al. 2010, Bergman et al. 2008). Stability measures (e.g. species loss speed) Study designs that make comparisons across habitat types, rather than across landscape gra-dients, find even fewer negative effects, and responses are predominantly positive for most taxa (Supplemental Table 4). For bees, the ratio of negative-to-positive responses decreases from 8.2 for extreme landscape studies to 2.0 for moderate landscape studies, to 0.5 for across-habitat comparisons. For butterflies, the ratios decrease from 6.0 to 3.0 to 1.1, respectively (Supple-mental Tables 2–4). The responses of syrphid flies and vertebrates are difficult to interpret due to the limited number of landscape-scale studies that have been conducted (Supplemental Tables 2 and 3). The reason why pollinator abundance and/or richness often decrease with increasing human land use in the surrounding landscape, but increase with conversion of natural to anthropogenic 8 Winfree·Bartomeus ·Cariveau Annu. Rev. Ecol. Evol. Syst. 2011.42:1-22. Downloaded from www.annualreviews.org ? ? by 67.139.62.82 on 11/18/11. For personal use only. ? ? ? ? ? ? 300 to 3,000 m radius a b Figure 3 Schematic showing the two study designs contrasted in this review. (a) Design focused on surrounding landscape cover. Sampling is generally done within a fixed habitat type. In the most common design, sites the proportion of surrounding land cover composed of specific habitat types such as forest (dark green) agriculture ( yellow). The radius at which landscape cover is assessed varies across studies but is typically between 300 and 3,000 m. Other designs, which we include in this category, vary either the linear distance to nearest habitat patch or the area of the habitat patch. (b) Design focused on local land-use type.These compare pollinator communities among different habitat types. The surrounding landscape cover the spatial extent of the habitat type where pollinators are sampled are generally not reported. Figure 4)]. Bees and butterflies both show strong negative responses to land-use change in extreme systems, butmoremixed responses inmoderate systems (Supplemental Tables 2 and 3). Extreme use causes a strong decrease in abundance and/or richness (e.g., Aizen & Feinsinger 1994, & Sodhi 2004, Kremen et al. 2002, Ockinger & Smith 2006), whereas studies in moderately anthropogenic landscapes find more varied responses (e.g., Bartomeus et al. 2010, Bergman et al. 2008). Study designs that make comparisons across habitat types, rather than across landscape gra-dients, find even fewer negative effects, and responses are predominantly positive for most taxa Supplemental Table 4). For bees, the ratio of negative-to-positive responses decreases from for extreme landscape studies to 2.0 for moderate landscape studies, to 0.5 for across-habitat comparisons. For butterflies, the ratios decrease from 6.0 to 3.0 to 1.1, respectively (Supple-mental Tables 2–4). The responses of syrphid flies and vertebrates are difficult to interpret to the limited number of landscape-scale studies that have been conducted (Supplemental Tables 2 and 3). The reason why pollinator abundance and/or richness often decrease with increasing human use in the surrounding landscape, but increase with conversion of natural to anthropogenic ·Bartomeus ·Cariveau
  10. 10. ? ? ? ? ? ? + + = Metaweb ? ? ? ? ? ? 300 to 3,000 m radius a b Figure 3 Schematic showing the two study designs contrasted in this review. (a) Design focused on surrounding landscape cover. Sampling is generally done within a fixed habitat type. In the most common design, sites vary in the proportion of surrounding land cover composed of specific habitat types such as forest (dark green) or agriculture ( yellow). The radius at which landscape cover is assessed varies across studies but is typically between 300 and 3,000 m. Other designs, which we include in this category, vary either the linear distance to the nearest habitat patch or the area of the habitat patch. (b) Design focused on local land-use type.These studies compare pollinator communities among different habitat types. The surrounding landscape cover and the spatial extent of the habitat type where pollinators are sampled are generally not reported. Figure 4)]. Bees and butterflies both show strong negative responses to land-use change in extreme systems, butmoremixed responses inmoderate systems (Supplemental Tables 2 and 3). Extreme land use causes a strong decrease in abundance and/or richness (e.g., Aizen & Feinsinger 1994, Koh & Sodhi 2004, Kremen et al. 2002, Ockinger & Smith 2006), whereas studies in moderately anthropogenic landscapes find more varied responses (e.g., Bartomeus et al. 2010, Bergman et al. 2008). Study designs that make comparisons across habitat types, rather than across landscape gra-dients, find even fewer negative effects, and responses are predominantly positive for most taxa (Supplemental Table 4). For bees, the ratio of negative-to-positive responses decreases from 8.2 for extreme landscape studies to 2.0 for moderate landscape studies, to 0.5 for across-habitat comparisons. For butterflies, the ratios decrease from 6.0 to 3.0 to 1.1, respectively (Supple-mental Tables 2–4). The responses of syrphid flies and vertebrates are difficult to interpret due to the limited number of landscape-scale studies that have been conducted (Supplemental Tables 2 and 3). The reason why pollinator abundance and/or richness often decrease with increasing human land use in the surrounding landscape, but increase with conversion of natural to anthropogenic 8 Winfree·Bartomeus ·Cariveau Annu. Rev. Ecol. Evol. Syst. 2011.42:1-22. Downloaded from www.annualreviews.org ? ? by 67.139.62.82 on 11/18/11. For personal use only. ? ? ? ? ? ? 300 to 3,000 m radius a b Figure 3 Schematic showing the two study designs contrasted in this review. (a) Design focused on surrounding landscape cover. Sampling is generally done within a fixed habitat type. In the most common design, sites the proportion of surrounding land cover composed of specific habitat types such as forest (dark green) agriculture ( yellow). The radius at which landscape cover is assessed varies across studies but is typically between 300 and 3,000 m. Other designs, which we include in this category, vary either the linear distance to nearest habitat patch or the area of the habitat patch. (b) Design focused on local land-use type.These compare pollinator communities among different habitat types. The surrounding landscape cover the spatial extent of the habitat type where pollinators are sampled are generally not reported. Figure 4)]. Bees and butterflies both show strong negative responses to land-use change in extreme systems, butmoremixed responses inmoderate systems (Supplemental Tables 2 and 3). Extreme use causes a strong decrease in abundance and/or richness (e.g., Aizen & Feinsinger 1994, & Sodhi 2004, Kremen et al. 2002, Ockinger & Smith 2006), whereas studies in moderately anthropogenic landscapes find more varied responses (e.g., Bartomeus et al. 2010, Bergman et al. 2008). Study designs that make comparisons across habitat types, rather than across landscape gra-dients, find even fewer negative effects, and responses are predominantly positive for most taxa Supplemental Table 4). For bees, the ratio of negative-to-positive responses decreases from for extreme landscape studies to 2.0 for moderate landscape studies, to 0.5 for across-habitat comparisons. For butterflies, the ratios decrease from 6.0 to 3.0 to 1.1, respectively (Supple-mental Tables 2–4). The responses of syrphid flies and vertebrates are difficult to interpret to the limited number of landscape-scale studies that have been conducted (Supplemental Tables 2 and 3). The reason why pollinator abundance and/or richness often decrease with increasing human use in the surrounding landscape, but increase with conversion of natural to anthropogenic ·Bartomeus ·Cariveau Overall structure (e.g. nestedness) Stability measures (e.g. species loss speed)
  11. 11. Map worldwide.
  12. 12. 2) Species contributing most to nestedness are more likely to go extinct
  13. 13. Each node nestedness contribution Permutation of the node values
  14. 14. Each node nestedness contribution Each node real loss order Permutation of the Rank of extinction node values Sites Pollinators ES42CH01-Winfree ARI 26 September 2011 12:49 ES42CH01-Winfree ARI 26 September 2011 12:49 ? ? 300 to 3,000 m radius a b ? ? ? ? ? ? ? ? 300 to 3,000 m radius a b Figure 3 Schematic showing the two study designs contrasted in this review. (a) Design focused on surrounding landscape cover. Sampling is generally done within a fixed habitat type. In the most common design, sites vary in the proportion of surrounding land cover composed of specific habitat types such as forest (dark green) or agriculture ( yellow). The radius at which landscape cover is assessed varies across studies but is typically between 300 and 3,000 m. Other designs, which we include in this category, vary either the linear distance to the nearest habitat patch or the area of the habitat patch. (b) Design focused on local land-use type.These studies compare pollinator communities among different habitat types. The surrounding landscape cover and the spatial extent of the habitat type where pollinators are sampled are generally not reported. Figure 4)]. Bees and butterflies both show strong negative responses to land-use change in extreme systems, butmoremixed responses inmoderate systems (Supplemental Tables 2 and 3). Extreme land use causes a strong decrease in abundance and/or richness (e.g., Aizen & Feinsinger 1994, Koh & Sodhi 2004, Kremen et al. 2002, Ockinger & Smith 2006), whereas studies in moderately anthropogenic landscapes find more varied responses (e.g., Bartomeus et al. 2010, Bergman et al. 2008). Study designs that make comparisons across habitat types, rather than across landscape gra-dients, find even fewer negative effects, and responses are predominantly positive for most taxa Annu. Rev. Ecol. Evol. Syst. 2011.42:1-22. Downloaded from www.annualreviews.org by 67.139.62.82 on 11/18/11. For personal use only. + +
  15. 15. For deciduous forests in US: Rachael Winfree
  16. 16. What drives extinction order then?
  17. 17. What drives extinction order then? More in Winfree et al. 2014 Am. Nat.
  18. 18. 1) nestedness confer stability
  19. 19. Nestedness Relative nestedness (NODF)
  20. 20. Nestedness % Links lost at 50% habitat destruction 50% habitat loss % links loss Relative nestedness (NODF) + +
  21. 21. link loss at 50% habitat loss
  22. 22. ? link loss at 50% habitat loss
  23. 23. This project is been possible thanks to... Data providers: Rachael Winfree, Dan Cariveau, Laura Burkle, Marie Winsa, Marcelo Aizen, Jennifer Wickens, Andrea Holzchuh, Juanpe Gonzalez-Varo, … but also to theory developers. Thank you @ibartomeus www.bartomeuslab.com nacho.bartomeus@gmail.com
  24. 24. ? Thank you @ibartomeus www.bartomeuslab.com nacho.bartomeus@gmail.com
  25. 25. What models do not take into account: Complexity! Species have different levels of dependencies on its partners Species may be regulated by other factors (e.g. nest sites) … Not a critique to the models/mechanisms, but to its relevance in real ecosystem.
  26. 26. What empirical data does not takes into account: Sampling artefacts Lack of measures of stability … (But see Bartomeus 2013 PLoS ONE) Not a critique to the observational studies, but to its ability to detect the signal.

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