What conservationists need to know about farming

 

Farming is the basis of our civilization. Though the world’s population is increasing largely and is expected to rise from the present 7 billion people to 9 billion by the year 2050 (UNPD, 2011) thus the demand for farm products increases accordingly. The United Nation’s Food and Agriculture Organization (FAO) estimates that the demand for food will rise 70 percent worldwide between year 2005 and 2050 (FAO, 2009). The great challenge for our civilization is that, although we are dependent on farming, at the same time farming is the most nature damaging sector of human activity to the planet. This is because farms are not closed systems but affect the surrounding environment. Biodiversity and wildlife are often the trade-off for farming. Tackling these issues requires conservationists to explore the many consequences that decisions about agriculture have beyond the farm. While it is important to consider conservation values on farmland, consideration also needs to be given to; what sorts of species are found where, the abundance of each species, agricultural yields, and the relative proportions of intact habitat and high- and low-yielding farming. There is a pressing need to measure how biodiversity varies with farm yield but also to consider other ecosystem services. We need to develop methods for how best to limit the cost of farming across a group of benefits important to society. Also it is important to identify likely “winners” based on data and not ideology when it comes to agricultural methods.  Land-sharing, land-sparing, push-pull, breeding and genetic modification techniques must be considered and evaluated. Further governmental regulation and land-use planning should likewise be considered, but with the market and consumer power in mind.

We discussed the advantages and disadvantages of land-sharing versus land-sparing. A member of the group shared experience of land-sharing not always being the best solution for enhancing ecological processes.  The group agreed that the most sustainable agricultural method in a given situation will be context and scale dependent. With the article’s example of nearly no research existing on chicken farming’s effect on the environment due to required cropland etc., a question on biodiversity was raised; could organic chicken farming be more harmful for the biodiversity than the conventional mass-production? Also discussed was the possibility of offering credit for farming biodiversity in order to motivate farmers to enhance biodiversity on their farms, since some farmers do care and listen to the public reactions of environmental impacts. It was suggested that increased diversity of farming within a landscape will increase biodiversity, though with that comment a discussion arose about agriculture responding to the market and that it is nearly impossible to put a price on biodiversity value. In addition, the issues of the general public only caring about conserving the cute animals and the pictures landscape was brought up with the question of; how can we make biodiversity valuable to the public?

Is the trade-off for biodiversity measurable? Is the bottom-line for a trade-off, between biodiversity and economic wealth? If so, where does that leave conservationists and the science of ecology?  

References

Balmford, Andrew et al., 2012, what conservationists need to know about farming, Proceedings of The Royal Society Journal, Biological Science.

FAO, 2009, Food and Agriculture Organization of the United Nations, State of food insecurity in the world 2009, Rome, Italy.

UNPD, 2011, United Nations Population Division, World population prospects: the 2010 revision. New York, United States.

 

Biodiversity and ecosystem services: Complementary approaches for ecosystem management?

Schneiders et al. (2012)

According to the Millenium Ecosystem Assessment (MA, 2003), ecosystem services (ES) are the benefits humans obtain from ecological systems. They can be classified as providing services, such as food; regulating services, like control of diseases; cultural services, as recreational; and supporting services, such as nutrient cycling. Many surveys are currently being conducted on ES, particularly addressing their economic valuation. These studies are contributing to the evaluation of strategies for alternative uses of land and, most importantly, may aid in demonstrating and justifying the urge for conserving biological diversity (Schneiders et al., 2012).

Furthermore, many researchers have stated that the quality and sustainability of ES could be directly influenced by, or strongly correlated with, the level of biodiversity of an ecosystem (MA, 2003, Cardinale et al., 2012, Schneiders et al., 2012). However, for many ES, the evidence for the effects that biodiversity has on them is mixed or insufficient. In addition, how biodiversity per se contributes to the ES is even less well defined (Cardinale et al., 2012).

This week’s paper aimed to resolve the much-discussed question ´Are biodiversity conservation, with the aim of preserving biodiversity, and ES, with the goal of sustaining human well-being, mutually beneficial or are trade-offs always inevitable?´. In order to address this aim, the authors:

• Analyzed the relations between biodiversity, ES and land use intensity for the region of Flanders through a comparison of their estimated values (generated by expert opinion) in grid maps (4km x 4 km). The researchers found a negative relationship between biodiversity and ES values and land use intensity values. 
• Described the relationships between biodiversity and land use intensity, for the long term future. Here, the authors discussed the importance of establishing a ´safe minimum standard of conservation´ (SMS) that is the ´lowest´ biodiversity level accepted by society. This SMS will help evaluating whether an ecosystem is healthy or not and if the use of ES are being sustainable.
• Applied ecosystem management in order to relate the current and the future target scheme. The researchers recommended different approaches of EM according to the characteristics of the areas: for zones with high levels of biodiversity, they recommended a biodiversity based approach; for zones with multifunctional uses and a good state as a future perspective, an ecosystem service approach was suggested; and for built-up zones and areas with intensive agricultural used, their advice was a technological service based approach. The authors suggested that by using this division of ecosystem management the joint achievement of biodiversity and ES goals would be easier. 

The discussion started with the statement that considering the main objective of ES is human well-being, conservation focusing on ES would focus mainly on species that make those kinds of services possible. Then, the group recognized the risk of this type of conservation for we only know few species and even less about their functions and the ES they are involved with. Therefore, it was stated that conservation efforts should focus on preserving as much as possible (the precautionary principle), except in those ecosystems where a specific ES is needed. 

Later, the discussion moved into ES being a buzzword. In the past, it helped to gather people from different disciplines together to talk about conserving biodiversity. Sadly, now ES is mainly being used as a tool for valuing how much money society can get from nature. The group recognized that the lack of environmental education and an emotional connection with nature would have predisposed societies to having an ‘I-only-care-about-having-money’ attitude. This lack of attachment to nature could be one of the causes that makes new generations insensitive to what happens around them and in their environment because they only care about getting the maximum profit from it. 

As for the paper itself, the group claimed that even though the findings obtained by the papers were not novel and they did not actually measure ES nor present any solution, the method of grid maps used was a good contribution for a spatial analysis and could be helpful in determining what type of management is appropriate according to the features of an area. The group also questioned the used of ´experts opinion´ in establishing the values for land use type (Appendix A of the paper).

Questions:

1. How can ecologists help current and future generations consider the importance of biodiversity and actually care about nature? A member of the group proposed including some ecology courses in the curricula. Will this be enough to change students´mentality?  
2. Considering that we cannot conserve all species, should conservation programs focus on species that provide ES? Will this actually help the conservation of the ecosystem and its functions? What about the other species?

 References:

1. Cardinale, B.J., Duffy, J.E., Gonzalez, A., Hooper, D.U., Perrings, C., Venail, P., Narwani, A., Mace, G.M., Tilman, D., Wardle, D.A., Kinzig, A.P., Daily, G.C., Loreau, M., Grace, J.B., Larigauderie, A., Srivastava, D.S., & Naeem, S. (2012). Biodiversity loss and its impact on humanity. Nature, 486(7401), 59–67. doi:10.1038/nature11148
2. MA. (2003). Millenium Ecosystem Assessment: Ecosystems and human well-being - a framework for assessment. Washington, U.S.A.: Island Press.
3. Schneiders, A., van Daele, T., van Landuyt, W., & van Reeth, W. (2012). Biodiversity and ecosystem services: complementary approaches for ecosystem management?. Ecological Indicators, 21(SI), 123-133. doi:10.1016/j.ecolind.2011.06.021

Why are metapopulations so rare?

Levins (1970) introduced the term 'metapopulation' to describe the concept of a population of populations. A metapopulation describes a set of subpopulations linked by rare dispersal events allowing for recolonizations after extinctions (Fronhofer et al. 2012). Interest in the metapopulation concept has increased substantially since the 1980s and since the mid-2000s c.400 articles relating to metapopulations have been published each year.

The metapopulation theory as defined by Levin (1969) has been frequently applied to conservation biology because two of its basic parameters are extinctions and recolonizations. The term has been used in a broad sense and despite the application to conservation biology very few empirical examples conform to the strict classical metapopulation model (CM) defined by Levins (Fronhofer et al. 2012).

Fronhofer et al. (2012) use the term spatially structured populations (SSP) to encompass metapopulations and other population structures such as mainland-island systems, source-sink and patchy populations. The group discussed the use of this terminology in ecology and how terms can be picked up by other disciplines and used in such a way that their meaning becomes vague or too broad. Hanski & Gilpin (1991) stated that ecology is afflicted with inconsistencies in the use of terms and concepts. Vague use of terms leads to grouping or splitting of ecological phenomena and can hinder attempts at understanding the real world.

Interestingly there was a lag phase in the uptake of the metapopulation theory. The theory of island biogeography dominated ecological thinking up to the late 1980s. The theory of island biogeography is related to the metapopulation concept in having the same fundamental processes: colonization and extinction (Hanski & Gilpin, 1991). The island biogeography theory looks at communities whereas the metapopulation theory relates to single species. One reason put forward for this lag by the discussion was that early work done on metapopulations were model driven. Empirical studies were difficult and time consuming to do. Social changes in the late 1980s brought environmental issues such as rainforest destruction to the fore. Metapopulation theory research was seen as a way of determining the consequences of habitat fragmentation. It also came to the forefront in the discussions on reserve design.

The importance of using the correct term was questioned: Does it matter if the term metapopulation or spatially structured population is used? The paper we discussed did address this question by suggesting assumptions may lead to resources being invested incorrectly leading to biodiversity loss. Management decisions for conservation have been based on the metapopulation theory but examples of the CM are rare in nature. The paper discussed states the CM concept is applicable to populations which are on the brink of extinction. These populations may already be too far down the track of extinction to save. The emphasis is on determining the type of SSP that is being conserved so the correct management decisions can be made (Fronhofer et al. 2012).

Does ecology need a system to create consistent definitions for ecological terminology?

Is the metapopulation concept relevant to applied areas such as conservation biology?

Is the individual-based modelling approach a useful tool for determining management strategies for conservation?

References

Fronhofer, E. A., Kubisch, A., Hilker, F. M., Hovestadt, T., & Poethke, H. J. (2012). Why are metapopulations so rare? Ecology, 93(8), 1967-1978.

Hanski, I., & Gilpin, M. (1991). Metapopulation dynamics: brief history and conceptual domain. Biological Journal of the Linnean Society, 42, 3-16.

Levins, R. (1969). Some demographic and genetic consequences of environmental heterogeneity for biological control. Bulletin of the Entomological Society of America, 15, 237-240.

Levins, R. (1970). Extinction. In M. Gerstenhaber (Ed.), Lectures on mathematics in the life sciences (Vol. 2). Providence, Rhode Island: American Mathematical Society.

Biodiversity for food and nutrition

Estimated 90 % of the world’s dietary energy supply is obtained from only 30 plant species, although more than 700 species through time have been cultivated for food (FAO, 1997). The forces behind this monocultural approach to agriculture are mainly economics, production volumes and market power of consumers. There is a great deal of variety in nutrient values even from the same species of fruit, grain or vegetable. The compositional difference among varieties or cultivars can be very significant for macronutrients, micronutrients and bioactive components. Different food species and a variety within species provides energy, nutrients thus contributes to food and nutrition security (Toledo & Burlingame, 2006). Data on the nutrient content of foods is very limited and this variation has been an ignored area of research, despite data on nutrient contents at the level of the genetic resource being important for the sectors of health, agriculture, trade and the environment. These sectors have different approaches for the use of such data, though some consensus can be reached towards a healthier population and healthier ecosystems. With agriculture of great variety in cultivars, the biodiversity in the ecosystems the agriculture exists in will accordingly be greater. According to the authors of the article; “food composition activities continue to improve the evidence base, which in turn gives value to ecosystems, the food species they contain, and the within-species diversity” (Burlingame et al. 2009).

We discussed the possibilities of using native species agriculture at larger scales; however, it is clear that the trade and economics are the determinant of agricultural cultivar use. Local communities might grow native species, such as potatoes in Peru, for their own use, but use high yield species for trade and export. In addition, we discussed the difference between the survival needs of local community farmers in comparison with the target of large scale agriculture to feed the world, and thus the pros and cons for the two sizes regarding profit and biodiversity. A member of the group even questioned the profit value of big scale agriculture versus loss of biodiversity.

From large scale agriculture to global money we also discussed the difference in ability to digest and absorb nutrients between world populations and continents. Nowadays people travel and move around the world, trends and advertisement follows thus the consumer behavior, demands and wanting follows too. The matching of physiological needs and abilities with the physical environment is being challenged in the attempt to make the world adapt to us. We further discussed the value of food and concluded it to be much more than only nutrition and physical needs, but also a social and cultural matter. With the example of children believing that eggs comes from Wal-Mart, the issues of respect and responsibility for agriculture and nature was raised.  

If our world is ruled by global money and trading, how can scientists make a difference in conserving nature, wildlife, biodiversity, etc.? How can different sciences cooperate in terms of reaching a common goal? And do we all have the same goal?

 

References:

Burlingame, B., 2009. Food composition is fundamental to the cross-cutting initiative on biodiversity for food and nutrition. Journal of Food Composition and Analysis, 22, 361-365.

FAO, 1997. State of world’s plant genetic resources for food and agriculture. FAO, Rome.

Toledo, A. & Burlingame, B., 2006. Biodiversity and nutrition: a common path toward global food security and sustainable development. Journal of Food Composition and Analysis 19, 477-483.

PhD reform

This week we will be discussing several recent articles calling for reform of the PhD system, which you can find here:

http://dx.doi.org/10.1038/472261a
http://dx.doi.org/10.1038/472276a
http://dx.doi.org/10.1038/472280a
http://dx.doi.org/10.1371/journal.pone.0036307
http://www.scientists.org.nz/files/journal/2012-69/NZSR_69-2.pdf (pp.30-39)

One of our members also suggested watching this video about broader issues of educational reform:

http://www.youtube.com/watch?v=zDZFcDGpL4U

Please feel free to discuss these articles using the comments section of this blog. All relevant contributions are welcome.

Using existing scientific capacity to set targets for ecosystem-based management: A Puget Sound case study

Samhouri¸ J.

Even though it has been more than 20 years since its creation, there is no consensus on the definition of Ecosystem Management (EM) or Ecosystem Based Management (EBM) yet. This has led to scientists and ecosystem managers giving this type of management their own interpretation and implementation (Grumbine, 1994; Simberloff, 1994).

Fundamentally, ecosystem management is a modern, holistic method of managing a biological system at an ecosystem level that explicitly considers humans as part of that system (Grumbine, 1994; Simberloff, 1994). This approach is promoted by major international organizations (i.e. UNEP, IUCN, and others) as the best solution for the current biodiversity loss crisis.

A frequent problem with the EBM approach is a lack of reference levels and indicators (values or range of values) to determine the current and desirable state of an ecosystem when it comes to managing it (Samhouri et al., 2011). Moreover, EBM relies on terms as ‘sustainability’ and ‘ecosystem health’, concepts whose meaning and measurement are still under debate (Simberloff, 1994). Consequently, it is very difficult to determine the success of an EBM program.

In this week’s paper, the authors reviewed five different approaches to establish reference levels to evaluate EBM programs: i) use of existing reference levels (applied to EBM without any modification), ii) reference directions (applied to EBM after a consensus when there are poor data), iii) reference levels based on nonlinear functional relationships (which identifies environmental conditions or management actions that lead either to slight or dramatic changes in the ecosystem), iv) reference levels based on baselines (taking information from three types of ¨pristine¨ ecosystems: prior to human activity, inside protected areas or from remote locations with minimal human pressure), and v) reference levels based on social norms (incorporating social values). Furthermore, the authors make a short analysis of the application of these five approaches in order to evaluate the Puget Sound EBM program, which has become a national model of how EBMs must be implemented in the USA.

The discussion group started by recognizing that even though the 5 approaches proposed by the authors were appropriate scientific methods to evaluate an EBM program, it was not clear if the case study used was successful or not in illustrating how to apply these approaches. Therefore, the paper left us with a sense of lack of information.

The discussion then focused on three major points:

1. People should be more educated in science: management and political decisions should be based on scientific information. Ecology predicts what could happen to the ecosystem if certain actions were taken, so decision makers should take this in consideration in order to reduce biodiversity loss.
2. Science should consider people: there were different comments about the importance of including the social factor into the management, conservation and study of ecosystems. The idea of considering people’s expectations, and how these may change over time, in this social values approach was stated.
3. There is an urgent need for interdisciplinary panels in the decision making process: scientists should be involved in these. The major challenges are having the participation of ecologists and finding a way of helping people from a non- scientific background understand the ecological information.

Regardless of the ambiguity around what EBM involves, many countries have adopted it as their novel mode to manage natural resources and ecosystem services. Therefore, there is a need to answer the following questions:

• Is it appropriate to adopt EBM when its definition and monitoring are not clear enough?
• In the 1990s, Grumbine (1994) and Simberloff (1994) stated that EBM was been criticized by many scientists (i.e., biologists, ecologists, conservationists) because this type of management considers human’s benefit as a leading point for its utilitarian point of view (ecosystem would be managed according to humans needs). In a 2012 context, what are ecologist’s opinions?
• Crow (1994), stated that EBM urges for close relationships between scientists and ecosystem managers. Then, Carpenter (1996) made a call to the ecological science community to get involve in EBM programs. In a 2012 context, how can we encourage this collaboration? 

References:

• Carpenter, R.A. (1996). Ecology should apply to ecosystem management: A comment. Ecological Applications, 6(4), 1373-1377.
• Crow, T. (1994). Ecosystem Management. Bulletin of the Ecological Society of America, 75(1), 33-35. Retrieved from: http://www.jstor.org/stable/20167817. 
• Grumbine, R.E. (1994). What Is Ecosystem Management?. Conservation Biology, 8(1), 27-38). doi:10.1046/j.1523-1739.1994.08010027.x  
• Samhouri, J., Levin, P., James, A., Kershner, J. & Williams, G. (2011). Using existing scientific capacity to set targets for ecosystem-based management: A Puget Sound case of study. Marine Policy, 35, 508-518. doi:10.1016/j.marpol.2010.12.002
• Simberloff, D. (1998). Flagships, umbrellas, and keystones: is single-species management passi in the landscape era?. Biological Conservation, 83(3), 247-257. doi:10.1016/S0006-3207(97)00081-5

Plant-herbivore coevolution in a changing world

Human impacts on the environment, such as habitat destruction and fragmentation, climate change, invasive species, over-exploitation and pollution are causing a rapid loss of biodiversity. We only have limited knowledge on the impacts of biodiversity loss on ecological and evolutionary processes. Much of what we know of current diversity loss is on single species level and little is known about the impact on species interactions (Leimu et al. 2012).

Coevolution as proposed by Ehrlich and Raven (1964) in their classic paper was responsible for much of the fantastic diversity found in modern insects. Plants evolved chemical defenses to protect themselves from herbivore damage and consequently insects evolved adaptions to these chemicals. Coevolution is seen to be a dominant process that has shaped much of the biodiversity on the planet.

Human induced environmental changes such as habitat fragmentation reduce populations sizes. Climate change may reduce the size of optimal habitat available for populations therefore contributing to population reduction. Small populations can lead to inbreeding and reduced genetic variation. These factors are likely to influence plant-herbivore coevoluntionary processes by affecting a species ability to respond to selection pressure (Leimu et al 2012).

The ability of some plants to become weeds in a non-native habitat has been attributed to their release from their coevolved natural enemy allowing reallocation of resources from chemical defense into growth and reproduction (Zangerl and Berenbaum, 2005). The introduction of biocontrol agent, generally a species that has coevolved with the invasive species may control the pest. Zangerl and Berenbaum (2005) give an example how a plant weed become more toxic after its natural enemy was released as a biocontrol agent. In the absence of its natural enemy the toxicity of the plant reduced but when the coevolutionary relationship was re-introduced the plant again began producing toxic chemicals. As shown by this example there is a need to consider the coevolutionary history of interacting species when proposing biocontrol of an invasive species.

The group discussion queried how would it be possible to determine if plant-herbivore coevolution had been conserved or even if it is possible to conserve such relationships.

The paper discussed concludes with Leimu et al. (2012) determining that urgent study is needed to investigate the interactive effects of the major drivers of biodiversity loss. A criticism of this continuing wish for more study was brought up by a member of the discussion group. How much investigation is needed before conservation action is taken? Martin et al. (2012) document the demise of a small insectivorous bat endemic to Christmas Island. The decline of the bat was documented from 1986 and the species has been monitored intensively since 2004. Sadly the bat is now extinction because of a lack of action even though it was very obvious that this species was in trouble with only 20 individuals left.

Is it possible to conserve plant-herbivore coevolution? Does it really matter whether or not ALL coevolving relationships are conserved? New Zealand plant species evolved without browsing mammals, can they or are they already coevolving with these new herbivores?

References

Ehrlich, P. R., & Raven, P. H. (1964). Butterflies and Plants: A Study in Coevolution? Evolution, 18, 586-608.

Leimu, R., Muola, A., Laukkanen, L., Kalske, A., Prill, N., & Mutikainen, P. (2012). Plant-herbivore coevolution in a changing world. Entomologia Experimentalis et Applicata, 144, 3-13.

Martin, T. G., Nally, S., Burbidge, A. A., Arnall, S., Garnett, S. T., Hayward, M. W., et al. (2012).

Acting fast helps avoid extinction. Conservation Letters, 0, 1-7.

Zangerl, A. R., & Berenbaum, M. R. (2005). Increase in toxicity of an invasive weed after reassociation with its coevolved hervivore. Proceedings of the National Academy of Sciences of the United States of America, 102(43), 15529-15532.

Global food security, biodiversity conservation and the future of agricultural intensification

The rapid increasing human population challenges our food supply in terms of achieving efficient and productive agricultural land use, while also conserving biodiversity. The debate whether land for nature and for production should be segregated (sparing) or integrated (sharing) with wildlife is ongoing. Inappropriate agricultural management can lead to environmental degradation and conventional agriculture intensification often results in contamination by pesticides and fertilizers, which can affect human health and create non-target effects on wildlife and functional agro biodiversity (Meehan et al., 2011).

Tscharntke et al. (2012) argues that implementing agro-ecological principals in agriculture, i.e. adopting eco-efficient and environmentally friendly management with a focus on more diversified cropping systems can greatly improve productivity and contribute to closing yield gaps. Further, Tscharntke et al. (2012) states that linking agricultural intensification with biodiversity conservation requires well-informed, regional solutions and the challenge is more complex that first assumed.

The paradox of scale is the phenomenon whereby small and diversified farmers, rather than large monocultures, show greater productivity per area (Horlings and Marsden, 2011). Community-managed forests suffer from lower deforestation rates than protected forests (Porter-Bolland et al., 2012), which highlights the importance of participation and involvement of rural communities.

We discussed the complexities of linking global food security, biodiversity and agricultural intensification. Food security is needed where the hungry live, which is often within a landscape matrix of ecosystems that are rich in biodiversity. Thus, the intensification of agriculture will necessarily be different from one place to another and from one country to another all depending on conditions, agricultural culture and history. This led to thoughts about interpretations of terms as environment, sustainability and organic farming.

To ecologists the issue is about land sparing versus land sharing, but for the average consumer it may be simpler; the choice of conventional versus organic products. Consumers are a part of the driving market power that determines whether the food is produced conventionally or organic. Pure and Green’s promotion for organic products gives a simplified suggestion of what organic means. Check out link for YouTube video (4:29 minutes). http://www.youtube.com/watch?v=BebNsezt6r0&feature=related

Is it that simple? Should we as scientists involve the general population more in the details on the consequences of agriculture? Is it important and possible to engage consumers in biodiversity and the effect of agricultural management?

References

Meehan, T.D., Werling, B.P., Landis, D.A., Gratton, C., 2011. Agricultural landscape simplification and insecticide use in the Midwestern United States. Proc. Natl. Acad. Sci. USA. doi:10.1073/pnas.1100751108.

Horlings, L.G., Marsden, T.K., 2011. Towards the real green revolution? Exploring the conceptual dimensions of a new ecological modernization of agriculture that could ‘feed the world’. Global Environ. Change.

Porter-Bolland, L., Ellis, E.A., Guaruiguata, M.R., Ruiz-Mallen, I., Negrete- Yankelevich, S., Reyes-Garcia, V., 2012. Community managed forests and forest protected areas: an assessment of their conservation effectiveness across the tropics. Forest Ecol. Manage. 268, 6–17.

 Tscharntke, T., Clough, Y., Wanger, T.C., Jackson, L., Motzke, I., Perfecto, I. Vandermeer, J., Whitbread, A. Global food security, biodiversity conservation and the future of agricultural intensification, Biological Conservation 151 (2012) 53–59.

Evolutionary Conservation of Species’ Roles in Food Webs

Stouffer, D.B., Sales-Prado, M., Sirer, M.I. & Bascompte, J.

For several years, conservation efforts around the world have been focused on single species (keystone, flagship and umbrella species). This approach has been criticized mainly for not considering ecological processes, and therefore being ineffective for preserving ecosystems (Simberloff, 1998). Nowadays, conservation programs are being planned based on a holistic approach, taking into consideration the functioning ecosystems and their associated ecosystem processes (Wilson et al., 2009). It is broadly known that the structure of a community and its capacity to remain functional are connected in a complex manner. Nevertheless, the degree of influence of a species’ identity on the persistence of the community it belongs to, as well as the variation degree of a species’ role as function of its community, is still uncertain. In order to fill that gap in our knowledge, this week’s discussion paper proposes a mathematical model based on “network motifs” that aims to determine the role played by a species and its importance in dynamics of a community. This model was tested using data from 32 empirical food webs from different environments, concluding that the species´ roles and their dynamic importance are inherent and intrinsic features developed as part of the evolution of taxa. Thus, some taxonomic groups tend to play the same role in different communities.

During our discussion, the group concluded that although the approach seemed very useful, the conclusions from the modelling were not new and that the authors could have done more to show how the model could be applied to the conservation of species and communities. Furthermore, some concepts like “benefits of the species” and community persistence were not properly explained in the main paper, leading to some confusion.

Question:

Besides identifying species’ roles in communities, how could this model be applicable and helpful in establishing conservation priorities?

References cited:

Simberlof, D. (1998). Flagships, umbrellas, and keystones: is single-species management passé in the landscape era?. Biological Conservation 83(3) 247-257.

Wilson, K. A., Carwardine, J. and Possingham, H. P. (2009), Setting Conservation Priorities. Annals of the New York Academy of Sciences, 1162: 237–264

Novel urban ecosystems, biodiversity, and conservation

Urban areas cover only approximately 3% of the total area of the earth’s land surface but urban growth is regarded as a major threat to biodiversity (Kowarik, 2011). 50% of the worlds population lives in urban areas and is increasing at an average annual rate of 1.9% (UN,2011). The importance of biodiversity in cities is seen by many to be not only a conservation issue but also a human health issue. Urban Ecology has a long history mainly in Europe. The succession of vegetation in bombed ruins of the Second World War was studied in many cities and in the 1970s ecological studies in cities started with investigations on energy flow and nutrient recycling. Urban ecology is now seen as a way to develop more sustainable cities and a mechanism to investigate how living organisms relate to their environment in cities (Sukopp, 2002).

This week’s discussion questioned the ecological role of increasing native biodiversity in urban areas. Are there benefits in trying to understand or enhance the ecological processes that may be occurring though increased native biodiversity? Kowarik (2011) states that conserving and enhancing urban biodiversity benefits human wellbeing and public health. Biodiversity also provides opportunities for people to interact with nature more often and therefore fosters a wider interest in nature conservation issues (Goddard et al. 2010). Has the social science behind these observations been studied and quantified? There is definitely a feel good factor in being part of restoring natural diversity to a city as seen by the number of groups involved in restoration in Christchurch and surrounding areas. But does this foster a greater interest in protecting our truly wild areas? A concern raised was that money could be diverted from conservation issues to fund biodiversity enhancement in urban areas giving little benefit to ecosystem functions.
What kinds of ecosystem functions can we create or restore in cities?

Cities as a whole are human-generated (Hobbs et al. 2006) novel systems, where species are thrown together in communities of compositions not found in nature. Urban ecology has shown cities to have both negative and positive impacts on biodiversity. Much of the plant diversity within a city is of an exotic nature causing cities to be hotbeds for exotic garden escapees, which can become pests in natural landscapes. On the other side of the coin can urban areas be seed sources and/or refuges for rare or endangered native species?

What is the scientific (and other) value of doing Urban Ecology? To answer this question I feel more research is needed on urban biodiversity and its related ecological and social implications.

References cited
Goddard, M. A., A. J. Dougill, and T. G. Benton. 2010. Scaling up from gardens: biodiversity conservation in urban environments. Trends in Ecology and Evolution 25:90-98.

Hobbs, R., S. Arico, J. Aronson, J. S. Baron, P. Bridgewater, V. A. Cramer, P. R. Epstein, J. J. Ewel, C. A. Klink, A. E. Lugo, D. Norton, D. Ojima, D. M. Richardson, E. W. Sanderson, F. Valladares, M. Vila, R. Zamora, and M. Zobel. 2006. Novel ecosystems: theoretical and management aspects of the new ecological world order. Global Ecology and Biogeography 15:1-7.

Kowarik, I. 2011. Noval urban ecosystems, biodiversity, and conservation. Environmental Pollution 159:1974-1983.

UN, 2011. Urban Population and Development 2011. UN, New York United Nations Department of Economic and Social Affairs. Population Division.

Biodiversity and ecosystem function

The ‘biodiversity and ecosystem function (BDEF) debate’ that has raged in ecology for several decades specifically addresses the question: Given the current unprecedented rate of extinction on Earth, to what extent does the loss of species affect how stable ecosystems are and what functions and services they provide? For instance, what is the effect of decline in plant species richness from a grassland ecosystem on properties such as nutrient cycling, decomposition rates, water capture and carbon sequestration? Numerous studies have shown that biodiversity influences ecosystem processes (and vice versa). In recent reviews, such as Naeem et al. (2012), which we discussed this week, it appears ecologists are trying to synthesise this large volume of work (showing that biodiversity does indeed have an effect on ecosystem function) and move the field on to the next stage of maturity – what have we learned over the last 20 years, how can we use this information and what should we be researching now? We felt that the Naeem et al. paper has some useful points in it, such as a box explaining seven ‘dimensions’ of biodiversity that provide six different ways of examining the effects of diversity on ecosystem function besides (the probably overused measure) species richness. The authors offer some well-stated challenges for future researchers including demonstrating effects in larger-scale, natural systems, accounting for these multiple forms of diversity as well as multiple ecosystem functions in their projects, using small amounts of information on species’ traits to predict trait states across greater numbers of species within ecosystems, and to start making the most of advanced technology such as pyrosequencing and newer statistical methods. The authors also remark on the importance of considering cultural values of biodiversity as another ecosystem service because although it is a non-utilitarian aspect of conservation, it is also important in terms of maintaining biodiversity.

Our discussion of this paper started us thinking about how useful the BDEF relationship is to ecology, conservation, and restoration ecology. We concluded first that the demonstration that biodiversity loss can impact ecosystem function justified what many of us do (try to understand spatio-temporal patterns in biodiversity in its various forms). Second, we discussed the notion that given that much of conservation applies to rare species conservation and the removal of rare species (e.g., the flightless New Zealand takahē (Porphyrio hochstetteri), decline in tussock grasslands of the South Island), doesn’t appear to affect the functioning of their native ecosystem, is it something that conservationists need to know or worry about? We concluded that the BDEF research was most relevant to restoration ecology where practitioners should want to know about the ecosystem-level effects of their efforts. We talked about integrating different measures of diversity and multiple ecosystem functions into our monitoring of restoration success.

We then moved on to a discussion of differences between ecosystem functions and ecosystem services and how these things might be measured in a restoration context. We talked about the effect of scale on evaluating restoration success, what restoration success was in general and what questions we needed answers to in order to make ‘recommendations’ to land managers who wanted advice on restoring a given area of land. We also debated the constraints on our ability to feed everyone on Earth now and into the future.

Questions:

·       We started to talk about how we would measure things in a real system, such as a restoration experiment, but it would be worthwhile to think more about this. How can ecosystem functions be measured? How can ecosystem services be measured?

·       Several other recent review papers were suggested to be relevant to our debate including Cardinale et al. (2012), Ehrlich et al (2012), and Hooper et al. (2012). How are these differ from the Naeem et al. paper?

References cited

Cardinale, et al. 2012. Biodiversity loss and its impact on humanity. Nature 486: 59-67.

Ehrlich et al. 2012. Securing natural capital and expanding equity to rescale civilization. Nature 486: 68-73.

Hooper et al. 2012. A global synthesis reveals biodiversity loss as a major driver of ecosystem change. Nature 486: 105-109.

Naeem et al. 2012. The functions of biological diversity in an age of extinction. Science 336: 1401-1406.