Diversified Farming Systems Roundtable of Berkeley Institute of the Environment

1. Diversified Farming SystemsRoundtable of Berkeley Institute of the Environment

2. Diversified Farming SystemsRoundtable of BIE

3. Diversified Farming SystemsRoundtable of BIE

4. Diversified Farming SystemsRoundtable of BIE

7. Ecosystem services and diversified farming systems Professor Claire Kremen University of California, Berkeley/ESPM BIE Roundtable Sept 16 2009

8. Ecosystem services Functions that natural ecosystems provide that sustain or improve human life Examples: flood control; nutrient cycling; decomposition; carbon storage, pest control, pollination Without these services we would not survive Fundamentally, these depend on biodiversity

9. Ecosystem Services inTraditional Diversified Agroecosystems Healthy ecosystems, not eroded, not flooded, not polluted�.Healthy ecosystems, not eroded, not flooded, not polluted�.

10. Traditional Agro-ecosystems Maintained Biodiversity Traditional agro-ecosystems maintained diversity across ecological levels and from the plot to landscape spatial scale by using techniques such as�.and thus naturally generated essential services that supported agriculture.Traditional agro-ecosystems maintained diversity across ecological levels and from the plot to landscape spatial scale by using techniques such as�.and thus naturally generated essential services that supported agriculture.

11. Intensive agriculture replaces services End with this: I�m going to focus on Monoculture and its critical role in causing agriculture to replace ecosystem services with technical fixes, which in turn endanger ecosystem services. End result, We still get the provisions out that we wanted. monoculture landscapes, biodiversity loss WITHIN agricultural areas We lose out on healthy ecosystems and instead end up with a whole host of negative externalities: unintended costsof agricultural practices that reduce the public good but do not cost the private farmer and are not passed on to the consumer in the marketplace. Not enough appreciation of the structural element: when we have monoculture, then we have pesticides (not the reverse). So its not enough to reduce pesticide use, we have to set up the conditions in which to do so. Worst of all, by replacing a lot of these services with man-made alternatives, we cause many environmental problems, called �negative externalities� � unintended consequences that often end up being � some one elses� problem, and that are not paid for by either the farmer (the producer) or the consumer. For example, We fix much more nitrogen doubling the rate of terrestrial nitrogen fixation in ecosystems, and then much of it ends up polluting our streams and oceans, causing algal blooms and even extremely large dead zones in the ocean � where nothing can live. So farmers activities along the Missisipi watershed affect fisher�s livelihoods in the Gulf of Mexico. That�s a classic externality. We pump ground-water � are reaching the limit on that, and causing saline waters from the oceans to invade ground water and ruin productive lands Use of pesticides � toxic effects on target and non-target organisms; drives evolution of resistant organisms, bio-accumulates up the food chain Overreliance on a single pollinator � honey bee ? colony collapse disorder puts many fruits. Vegetables at risk. Mechanization leads to greater soil erosion and compaction; fossil fuel use (also in fertilizer and pesticide production) Loss of animals on farms and putting them in feedlots � huge sewage problems, but waste ends up in rivers, streams, rather than closing the loop back to the farm, requiring input of fertilizer. One of the only things that we don�t control is climate (except in greenhouses, which is a small proportion of agriculture). This means of course that agriculture is highly vulnerable to climate change.End with this: I�m going to focus on Monoculture and its critical role in causing agriculture to replace ecosystem services with technical fixes, which in turn endanger ecosystem services. End result, We still get the provisions out that we wanted. monoculture landscapes, biodiversity loss WITHIN agricultural areas We lose out on healthy ecosystems and instead end up with a whole host of negative externalities: unintended costsof agricultural practices that reduce the public good but do not cost the private farmer and are not passed on to the consumer in the marketplace. Not enough appreciation of the structural element: when we have monoculture, then we have pesticides (not the reverse). So its not enough to reduce pesticide use, we have to set up the conditions in which to do so. Worst of all, by replacing a lot of these services with man-made alternatives, we cause many environmental problems, called �negative externalities� � unintended consequences that often end up being � some one elses� problem, and that are not paid for by either the farmer (the producer) or the consumer. For example, We fix much more nitrogen doubling the rate of terrestrial nitrogen fixation in ecosystems, and then much of it ends up polluting our streams and oceans, causing algal blooms and even extremely large dead zones in the ocean � where nothing can live. So farmers activities along the Missisipi watershed affect fisher�s livelihoods in the Gulf of Mexico. That�s a classic externality. We pump ground-water � are reaching the limit on that, and causing saline waters from the oceans to invade ground water and ruin productive lands Use of pesticides � toxic effects on target and non-target organisms; drives evolution of resistant organisms, bio-accumulates up the food chain Overreliance on a single pollinator � honey bee ? colony collapse disorder puts many fruits. Vegetables at risk. Mechanization leads to greater soil erosion and compaction; fossil fuel use (also in fertilizer and pesticide production) Loss of animals on farms and putting them in feedlots � huge sewage problems, but waste ends up in rivers, streams, rather than closing the loop back to the farm, requiring input of fertilizer. One of the only things that we don�t control is climate (except in greenhouses, which is a small proportion of agriculture). This means of course that agriculture is highly vulnerable to climate change.

12. DFS: Restoring ecosystem services to agro-ecosystems If we were to think about borrowing some of these techniques from traditional agriculture, and re-inserting some of them into modern industrial agriculture, we might be able to bring back some of these services and make the whole endeavor of agriculture more sustainable. Fundamentally, this means rediversifying from plot to landscape scale. Most of these techniques h ave multiple benefits.If we were to think about borrowing some of these techniques from traditional agriculture, and re-inserting some of them into modern industrial agriculture, we might be able to bring back some of these services and make the whole endeavor of agriculture more sustainable. Fundamentally, this means rediversifying from plot to landscape scale. Most of these techniques h ave multiple benefits.

13. Disservices, e.g. Riparian Corridors Before we get too rosy eyed The devil is in the details, and these are the details that we really need to figure out Which farming practices produce net benefits This is likely to be quite different for different crops and in different ecological contexts.Before we get too rosy eyed The devil is in the details, and these are the details that we really need to figure out Which farming practices produce net benefits This is likely to be quite different for different crops and in different ecological contexts.

14. What do we already know about relationship between DFS and ES? Agro-biodiversity Pollination Pest control What are the gaps?

15. Land use intensityLocal & Landscape scales Unfortunately there is a lot of inconsistent terminology used which makes matters confusing. I will try to be consistent. Two basic axes: Local management: management within the field or at whole field scale. Monoculture with high input to diversified with low input, and of course this is a spectrum with many intermediates Other words that you might associate with the monoculture high input are �intensive, industrial, conventional��. Other words you might associated with diversified low input: are �extensive, organic� but both are inadequate: diversified agriculture can be practiced very intensively (e.g. biodynamic gardening) and organic farming is not necessarily diversified. LANDSCAPE SCALE: Across an entire region, including multiple fields as well as potentially non-crop habitats : diversity and configuration of habitat types Simple: few non-crop habitats leading to homogenous landscape Complex: many crop habitat leading to heterogeneous landscape So you can divide things up, into four basic bins, although this is of course both artifical and problematic�. Complications: Organic tomato field -- intermediate in diversity, low in inputs CNV truck farm � high in diversity, but also in inputs�Unfortunately there is a lot of inconsistent terminology used which makes matters confusing. I will try to be consistent. Two basic axes: Local management: management within the field or at whole field scale. Monoculture with high input to diversified with low input, and of course this is a spectrum with many intermediates Other words that you might associate with the monoculture high input are �intensive, industrial, conventional��. Other words you might associated with diversified low input: are �extensive, organic� but both are inadequate: diversified agriculture can be practiced very intensively (e.g. biodynamic gardening) and organic farming is not necessarily diversified. LANDSCAPE SCALE: Across an entire region, including multiple fields as well as potentially non-crop habitats : diversity and configuration of habitat types Simple: few non-crop habitats leading to homogenous landscape Complex: many crop habitat leading to heterogeneous landscape So you can divide things up, into four basic bins, although this is of course both artifical and problematic�. Complications: Organic tomato field -- intermediate in diversity, low in inputs CNV truck farm � high in diversity, but also in inputs�

16. Ecology: why local to landscape scales matter, pollinators and natural enemies

17. Meta-analysis: quantitative method for analyzing results from independent studies asking same question 63 studies comparing biodiversity (different taxa) on organic and conventional fields Many taxa and biomesMany taxa and biomes

18. Overall Result A highly significant positive effect of organic on species richness & abundance Most (> 80%) of studies showed positive effects of organic farming on richness and abundance, leading to: Mean ? in species richness of 30% Mean ? in abundance of 50% Acrsoo all taxaAcrsoo all taxa

19. Taxonomic Differences In general, organic favored some of the groups that supply services on farms such as pest control. There was no increase in pest insect abundance on organic farms, in fact the trend wasIn general, organic favored some of the groups that supply services on farms such as pest control. There was no increase in pest insect abundance on organic farms, in fact the trend was

20. Effects of scale These effects were highly significant when drawing comparison between plots within a field (experimental) or between fields. When landscape context was taken into account (N=25), organic to conventional comparisons were not significant! However, a weakness of the above studies was that they had not taken landscape context into account Taking landscape context into account means that for the 25 studies in which organic versus conventional farm fields were compared within matched landscapes, there was no significant effect of organic management.However, a weakness of the above studies was that they had not taken landscape context into account Taking landscape context into account means that for the 25 studies in which organic versus conventional farm fields were compared within matched landscapes, there was no significant effect of organic management.

21. Tscharntke has forcefully argued and it is borne out not only by the Bengston review but in many other studies that the local impact on diversity is highly context dependent. In a simple landscape, there can be a large effect of local mgmt, but that effect is relatively minimal in a complex landscape, where the heterogeneity in the landscape itself is having the large effect. Figure�2�Diversity of arable weeds in relation to local management (extensive vs. intensive) and landscape composition (simple vs. complex; based on findings of Roschewitz et�al. 2005). Intensive farming means conventional practices with applications of mineral fertilizers and pesticides, contrasting with extensive (organic) farming. The solid lines show the different responses, while the dotted lines are for orientation only and indicate that diversity is higher in organic fields, while landscape complexity can compensate for the intensive conventional agriculture. In addition to this weed biodiversity pattern, the higher weed cover means enhanced cereal aphid control (I. Roschewitz, T. Tscharntke and C. Thies, 2005, personal communication).Tscharntke has forcefully argued and it is borne out not only by the Bengston review but in many other studies that the local impact on diversity is highly context dependent. In a simple landscape, there can be a large effect of local mgmt, but that effect is relatively minimal in a complex landscape, where the heterogeneity in the landscape itself is having the large effect. Figure�2�Diversity of arable weeds in relation to local management (extensive vs. intensive) and landscape composition (simple vs. complex; based on findings of Roschewitz et�al. 2005). Intensive farming means conventional practices with applications of mineral fertilizers and pesticides, contrasting with extensive (organic) farming. The solid lines show the different responses, while the dotted lines are for orientation only and indicate that diversity is higher in organic fields, while landscape complexity can compensate for the intensive conventional agriculture. In addition to this weed biodiversity pattern, the higher weed cover means enhanced cereal aphid control (I. Roschewitz, T. Tscharntke and C. Thies, 2005, personal communication).

22. this is simply a negative exponential with alpha for each study standardized to 1.0 and mean(mean beta) plugged in as the decay parameter. the grey area is the 90% credible interval, which means we can be 90% certain that the mean(mean beta) is within the shaded region. so this is the general decline best supported by the 23 studies. (for native visitation)this is simply a negative exponential with alpha for each study standardized to 1.0 and mean(mean beta) plugged in as the decay parameter. the grey area is the 90% credible interval, which means we can be 90% certain that the mean(mean beta) is within the shaded region. so this is the general decline best supported by the 23 studies. (for native visitation)

24. Note: collective local action of many growers can contributes to a significant landscape effect Figure 2. Effect of the organic land cover in landscape sectors with a 500m radius on the species richness of bees in 42 fallow strips adjacent to organic wheat fields (triangles with solid lines in) and conventional wheat fields (circles and dashed line). Results are from multi-factor mixed-effects models. See also Table 2Note: collective local action of many growers can contributes to a significant landscape effect Figure 2. Effect of the organic land cover in landscape sectors with a 500m radius on the species richness of bees in 42 fallow strips adjacent to organic wheat fields (triangles with solid lines in) and conventional wheat fields (circles and dashed line). Results are from multi-factor mixed-effects models. See also Table 2

25. Organic farms, can serve as little oases� Simplify �Look at it a different way. CAN SEE THAT BEES NESTING AT conventional farms that are isolated from natural habitats produce much fewer offspring than bees on organic or riparian sites that are isolated. There are no differences between site types when farms are not isolated. The black lines show the mean number of surviving offspring, which shows same statistical pattern. You can see that on Conv Farms, do not have enough offspring to replace themselves. SINK populations. A large part of landscape. Organic farms, can serve as little oases� Simplify �Look at it a different way. CAN SEE THAT BEES NESTING AT conventional farms that are isolated from natural habitats produce much fewer offspring than bees on organic or riparian sites that are isolated. There are no differences between site types when farms are not isolated. The black lines show the mean number of surviving offspring, which shows same statistical pattern. You can see that on Conv Farms, do not have enough offspring to replace themselves. SINK populations. A large part of landscape.

26. At wheat ripening, complex landscapes were related to higher parasitism than simple landscapes, presumably due to more overwintering sites, alternative hosts and nectar sources for parasitoids. However, aphid population densities were also higher in complex landscapes, presumably due to the high availability of winter hosts for these host-alternating species. We conclude that complex landscapes with low percentage of arable land appeared to enhance parasitism, but also the host-alternating aphids, so overall effects of landscape complexity on cereal aphid control appear to be ambivalent. Roschewitz, I., M. Hucker, T. Tscharntke, and C. Thies. 2005. The influence of landscape context and farming practices on parasitism of cereal aphids. Agriculture Ecosystems & Environment 108:218-227. At wheat ripening, complex landscapes were related to higher parasitism than simple landscapes, presumably due to more overwintering sites, alternative hosts and nectar sources for parasitoids. However, aphid population densities were also higher in complex landscapes, presumably due to the high availability of winter hosts for these host-alternating species. We conclude that complex landscapes with low percentage of arable land appeared to enhance parasitism, but also the host-alternating aphids, so overall effects of landscape complexity on cereal aphid control appear to be ambivalent. Roschewitz, I., M. Hucker, T. Tscharntke, and C. Thies. 2005. The influence of landscape context and farming practices on parasitism of cereal aphids. Agriculture Ecosystems & Environment 108:218-227.

28. Generalities Note that the local management in isolated sites will have few spill-over effects (see Kohler et al 2007) � no time to go into this detail but will keep the slide in case it comes up.Note that the local management in isolated sites will have few spill-over effects (see Kohler et al 2007) � no time to go into this detail but will keep the slide in case it comes up.

29. Knowledge Gaps Pest control services vStimulation of natural enemy population Colonization of fields by natural enemies Reducing pest densities Reducing damage levels Increasing yield Improving cost-benefit Bianchi et al 2006 Pollination services v Stimulation of pollinator populations Pollinator populations providing pollination services Increasing yield Improving cost-benefit The pollinator community is well organized�.and is carrying out a great deal not only of field work but of synthetic work.The pollinator community is well organized�.and is carrying out a great deal not only of field work but of synthetic work.

30. Local management Organic to conventional is most common comparison Study wider variety of management types; classify them according to diversity at multiple scales Landscape issues How much non-crop area is enough? How arranged? Can good local management substitute for non-crop habitats, and if so, how much area? Cross-cutting questions for DFS

31. A parting question

32. Figure 4. Relationship between species density (a: hover flies, b: bees) and number of individuals (c: hover flies, d: bees) and the distance from the artificial flower rich patch. In grey: mean (continuous line) ? standard error (broken line) density of species or number of individuals in a landscape with no impact of an artificial flower rich patch control, n = 50). The tests are performed for each distance separately (n = 5) against the control (n = 50) by taking the region and the number of inflorescences of insect-pollinated plants into account (model: region + number of wild flowers + treatment). The indicated P-values are those of the treatment effect. * P < 0.05, *** P < 0.001.Figure 4. Relationship between species density (a: hover flies, b: bees) and number of individuals (c: hover flies, d: bees) and the distance from the artificial flower rich patch. In grey: mean (continuous line) ? standard error (broken line) density of species or number of individuals in a landscape with no impact of an artificial flower rich patch control, n = 50). The tests are performed for each distance separately (n = 5) against the control (n = 50) by taking the region and the number of inflorescences of insect-pollinated plants into account (model: region + number of wild flowers + treatment). The indicated P-values are those of the treatment effect. * P < 0.05, *** P < 0.001.

35. Figure�4�Effectiveness of agri-environment schemes in relation to landscape type. Effectiveness is measured as biodiversity enhancement because of management, such as the conversion from conventional to organic farming (Roschewitz et�al. 2005) or the creation of crop field boundaries (Thies & Tscharntke 1999; Tscharntke et�al. 2002a), compared with unmanaged control sites. Landscape type is classified as cleared (minimum diversity, <�1% non-crop habitat), simple (low diversity, 1�20% non-crop habitat) and complex (high diversity, >�20% non-crop habitat; see Andr�n 1994; Tscharntke et�al. 2002a). The resulting hump-shaped relationship is due to the different source pools in the surrounding landscape for recolonization of managed habitat. In cleared landscapes, the very few species are not a sufficient basis to result in a recognizable response to management changes. Similarly, in complex landscapes, management does not result in a significant effect, because biodiversity is high everywhere. In contrast, simple landscapes support intermediate species pools that allow a significant response to management.Figure�4�Effectiveness of agri-environment schemes in relation to landscape type. Effectiveness is measured as biodiversity enhancement because of management, such as the conversion from conventional to organic farming (Roschewitz et�al. 2005) or the creation of crop field boundaries (Thies & Tscharntke 1999; Tscharntke et�al. 2002a), compared with unmanaged control sites. Landscape type is classified as cleared (minimum diversity, <�1% non-crop habitat), simple (low diversity, 1�20% non-crop habitat) and complex (high diversity, >�20% non-crop habitat; see Andr�n 1994; Tscharntke et�al. 2002a). The resulting hump-shaped relationship is due to the different source pools in the surrounding landscape for recolonization of managed habitat. In cleared landscapes, the very few species are not a sufficient basis to result in a recognizable response to management changes. Similarly, in complex landscapes, management does not result in a significant effect, because biodiversity is high everywhere. In contrast, simple landscapes support intermediate species pools that allow a significant response to management.

36. Plants are the bottom line so this is something you might want to show early on... The relationships between plant species richness (per 100?m2) and annual nitrogen input on (a�c) grasslands and (d�f) arable fields produced by different statistical models. (a,d) all species, (b,e) rare species and (c,f) subdominant species. Black dashed lines indicate the relationships obtained with a linear function between species richness and N input; black solid curves indicate the relationships obtained with the best parametric model with a curvilinear function; and grey dashed curves indicate the relationships obtained with the best general additive model (table 2). Depicted relationships are obtained with fixed values for the environmental variables (grasslands: a site in Switzerland with latitude 47.385�, temperature 13.6�C; arable fields: a site in Germany with latitude 51.495�, temperature 13.7�C). Circles indicate the original species richness data for each site and are not corrected for confounding environmental factors.Plants are the bottom line so this is something you might want to show early on... The relationships between plant species richness (per 100?m2) and annual nitrogen input on (a�c) grasslands and (d�f) arable fields produced by different statistical models. (a,d) all species, (b,e) rare species and (c,f) subdominant species. Black dashed lines indicate the relationships obtained with a linear function between species richness and N input; black solid curves indicate the relationships obtained with the best parametric model with a curvilinear function; and grey dashed curves indicate the relationships obtained with the best general additive model (table 2). Depicted relationships are obtained with fixed values for the environmental variables (grasslands: a site in Switzerland with latitude 47.385�, temperature 13.6�C; arable fields: a site in Germany with latitude 51.495�, temperature 13.7�C). Circles indicate the original species richness data for each site and are not corrected for confounding environmental factors.

37. Example : in this case the main trend is not whether the local farm management type is organic versus conventional, but is depending on the surrounding landscape. Species diversity was most strongly related to the heterogeneity of the landscape at a 400 x 400 m scale, while abundance was related to a larger scale (5 km x 5 km) Weibull, A. C., J. Bengtsson, and E. Nohlgren. 2000. Diversity of butterflies in the agricultural landscape: the role of farming system and landscape heterogeneity. Ecography 23:743-750. Example : in this case the main trend is not whether the local farm management type is organic versus conventional, but is depending on the surrounding landscape. Species diversity was most strongly related to the heterogeneity of the landscape at a 400 x 400 m scale, while abundance was related to a larger scale (5 km x 5 km) Weibull, A. C., J. Bengtsson, and E. Nohlgren. 2000. Diversity of butterflies in the agricultural landscape: the role of farming system and landscape heterogeneity. Ecography 23:743-750.

38. Possibly I should leave this slide out. Jackson�s Complex Ag = refers to greater emphasis on renewable inputs, rotations, reduced tillage, polycultures, hedgerows, but included a wide array of management types. Identified through a clustering procedure. Definitely at local scale. Main points: Complex agriculture is intermediate between natural forests and intensified forms of agriculture across many different taxanomic groups and biomes. Trends are to less diversity than in natural habitat (due to disturbance) but definitely higher diversity than in highly intensive agriculture. Onereasons that complex ag comes out as intermediate rather than distinctly better than intensified. Surrounding Landscape complexity not taken into account and may be muddying the water. Complex Ag includes so many different management types also, may also muddy the water in comparing against intensive. Figure 13.2: Response of species richness to management intensification quantified by meta-analysis of field studies across four ecosystem types in agricultural landscapes, showing the mean effect size statistic for each ecosystem, based on the mean species richness for an ecosystem within a site in relation to the maximum observed richness in the study (see text). Ecosystem types were determined by Partitioning Along Metroids (PAM), and four clusters were identified: Forest-Grassland/ Pastures/ Abandoned- Complex Agroecosystems- Intensified Agroecosystems. Studies included many types of taxa and biomes (Table 13.1). Effect size means that share lower-case letters do not differ significantly (P = 0.05) based on pairwise t-tests; error bars are standard errors.Possibly I should leave this slide out. Jackson�s Complex Ag = refers to greater emphasis on renewable inputs, rotations, reduced tillage, polycultures, hedgerows, but included a wide array of management types. Identified through a clustering procedure. Definitely at local scale. Main points: Complex agriculture is intermediate between natural forests and intensified forms of agriculture across many different taxanomic groups and biomes. Trends are to less diversity than in natural habitat (due to disturbance) but definitely higher diversity than in highly intensive agriculture. Onereasons that complex ag comes out as intermediate rather than distinctly better than intensified. Surrounding Landscape complexity not taken into account and may be muddying the water. Complex Ag includes so many different management types also, may also muddy the water in comparing against intensive. Figure 13.2: Response of species richness to management intensification quantified by meta-analysis of field studies across four ecosystem types in agricultural landscapes, showing the mean effect size statistic for each ecosystem, based on the mean species richness for an ecosystem within a site in relation to the maximum observed richness in the study (see text). Ecosystem types were determined by Partitioning Along Metroids (PAM), and four clusters were identified: Forest-Grassland/ Pastures/ Abandoned- Complex Agroecosystems- Intensified Agroecosystems. Studies included many types of taxa and biomes (Table 13.1). Effect size means that share lower-case letters do not differ significantly (P = 0.05) based on pairwise t-tests; error bars are standard errors.