An Analysis of the Landscape Management of the Luberon-Lure Region and its Effect on Biodiversity

An Analysis of the Landscape Management of the Luberon-Lure Region and its Effect on Biodiversity
Oral Grade:

Written Grade: C+

By: Aufderheide, Ina; Anokye, Kenneth Darko; Dramez, Benoit; Latherow, Tamisan; Lombard, Lucie; Prudhon, Marie; Stuber, Moritz

Acknowledgements 

We would like to thank Dr. Alexander WEZEL and Dr. Aurélie FERRER for the organization and the management of the excursion. Their dedicated work made this excursion unique and unforgettable.

We also would like to thank all the different actors we met during the week, the various members of the PNR, farmers, and consumers. Thank you for your time and for the very interesting exchanges we had.

Finally, we want to express our gratitude to the employees of Maison de la Boucheyronne for their warm welcome. 

Introduction

“The Luberon Nature Park is one of 7 nature parks in Provence-Alpes-Côte-d'Azur overlapping the Vaucluse and the Alpes-de-Haute-Provence” (Office de Tourisme Luberon Monts de Vaucluse, n.d.). The Luberon Regional Nature Park (Parc Naturel Régional, PNR) was created in 1977. It is ruled by a Charter, which has to be renewed every 12 years, with each municipality that wants to join or stay in the Park signing it (the current charter will have to be renewed in 2021). Today 50 people are employed by the PNR. The PNR encompasses most of the Luberon region (personal communication, Ms. CHARLES, PNR) and includes a Biosphere Reserve, natural zones of ecological, faunistic and floral interests (ZNIEFF), Natura 2000 zones and a Geopark. Due to the pedoclimatic conditions and the different land uses of the region, the Luberon is a biodiversity hotspot. 

Biodiversity is defined as being “manifested at all levels of [an] organization (genes, species, ecosystems and landscapes) and is seen in all forms of life, habitats and ecosystems (tropical forests, oceans and seas, savannah ecosystems, wetlands, drylands, mountains, etc.)” (UNESCO, 2018). The Luberon region is home to a large number of species [1,500 plant species (30% of the French flora), 135 bird species (50% of the French fauna) and 2,300 butterfly species (40% of the French fauna)] (Parc Naturel Regional du Luberon, 2017) and includes mountain chains (Petit Luberon, Grand Luberon, Luberon Oriental and Monts de Vaucluse), valleys (like Vallée du Calavon), rivers (including the Durance) and floodplains. The mountains of the Petit and Grand Luberon include a lot of different rare ecological communities such as the Tilio-Acerion forests on slopes, and the Quercus ilex and Quercus suber forest. At the top of the mountains, there are endangered animals found on the Limestone Grasslands, like the Egyptian Vulture (Neophron percnopterus) and Short-Toed Snake Eagle (Circaetus gallicus), some of whom nest in the rock faces. 

The goal of the Biodiversity Group was to look at the landscape management by the various stakeholders (such as farmers or park managers) and how the land use affects the biodiversity of the Luberon region. This included interviewing several managers within the Park including at the Maison de la Biodiversité and Natura 2000 sites. Further stakeholders included a wine cooperative, vineyard, goat cheese cooperative, sheep farmer and conservation center focusing on plants used for textile dyes. The combined input from these various stakeholders allowed the group to formulate conclusions on the state of biodiversity in the region.

Research Questions and Hypothesis

The research questions are:

• What is the role of each actor in terms of biodiversity management and how do they contribute to it in the region ? 
• How effective are the initiatives taken at the Park level and what are the strengths and weaknesses of these initiatives in this region? 

Hypothesis: The PNR monitors biodiversity on a large area and leads several biodiversity conservation projects involving multiple stakeholders. However, it does not have the authority to enforce legal regulations over the entire region.

Material and Methods

Methods include a five day excursion (see Figure 1 for map of visited locations) to conduct interviews, farm visits, a car transect and a landscape overview. Before the excursion, the Biodiversity Group conducted an internet search and created questionnaires based on their findings for the different actors. The questionnaire (Annex 1) was divided into parts, each one for the different stakeholders that were to be interviewed. They include:

• General questions which are the most important to ask to all the stakeholders
• A section for each stakeholder focusing on:
• Primary stakeholders: a PNR ranger from the Natura 2000 sites, the cedar forest manager, and employees at the Maison de la Biodiversité;
• Secondary stakeholders: farmers, cooperative directors, local conservation group, and a superior technician from the hunting federation.

The aim of the questionnaire is to collect precise information on the activities of the different stakeholders in terms of biodiversity management. The group concentrated mainly on the missions of each actor, the means and their effectiveness to implement measures, and the main issues encountered for biodiversity preservation (such as climate change and invasive species concerns). Most of the interviews were recorded to facilitate the accuracy of interview notes. Recordings from each interview were procured and utilized.

In order to evaluate the land use and its diversity, the group also conducted a transect drive. Accompanied by a teacher, Dr. Wezel, the group drove along a secondary road and split into two groups for observational purposes. Each group looked at a side of the road and noted each type of land use visible from the mini bus. After a few kilometers the group stopped and discussed together the diversity of the activities on the territory viewed. 

Figure 1  Map of the municipalities visited, Source: (http://luberon.fr/infos-pratiques/carte-du-luberon/carte-parc-naturel-regional-luberon/ )

Results:

The PNR has official recognition at regional and national levels. The missions of the PNR are written in a formal document called the Charter and include:

• Site protection of the landscape, environment, and territory;
• Economic activity in favor of local development, tourism, economy, and agricultural development;
• Promotion and education of the territory;
• Land protection, architecture, and urban planning;
• Water planning, protection, quality of water, rivers, and lakes;
• Counselling for territorial collectives in terms of energy savings and renewable energy.

The council of the PNR is composed of local stakeholders, including the municipalities, the two Départements (Vaucluse and Alpes-de-Haute-Provence), the Region PACA, and local organizations. The main means used to put the missions into action is negotiation. The park has little legal power and must collaborate with the municipalities and the Préfectures of the Départements to have new rules enforced (for instance restrictions to access sections of the park). This is also because there are many other actors involved in the management and implementation of policies and practices. Shown below are the various actors the PNR cooperates with in the region (see table 1). Financing for the PNR is by the Fondation de France, the 2 Départements, the Region PACA, the French State and the European Union (EU) (personal communication Ms. Charles, PNR Agriculture Service). 

Forest Management

In the Petit Luberon region, the PNR cooperates with shepherds to manage high pastures (to conserve the Limestone Grasslands (European Commission, 2008)) and to do silvopastoralism in the mountain slopes. For silvopastoralism, the optimal mountain pasture management accounts for 600 sheep grazing in the region for one month, and expenses for the shepherd are covered by the PNR (personal communication Ms. Bourlon, PNR).

Among the forests of the Luberon, one particular site is the Cedar Forest whose first tree was planted in 1860. Later, from the 1950s to the 1970s, the National Forest Office (ONF) re-forested ridges of the Luberon with black pines and cedars (Garde et al., 2011). Seeds and seedlings of the various tree species  continue to be sent to other regions so the genetic diversity can be spread around and new plantings added to create habitat zones, new economic opportunities, and to assist with soil preservation on the slopes. As manager of the forests in the park, the PNR is responsible for working with forest plot owners and users to manage the wild animal populations, sheep grazing on mountain meadows and hillsides, and coordinating hunting and tourism seasons (personal communication, Ms. Bourlon, PNR). 

Many animal species of interest are linked to the forest; their viability is a big subject for the park. Some relevant species in the region are the Egyptian Vulture (Neophron percnopterus) and Bonelli's Eagle (Aquila fasciata), which are listed as threatened (International Union for Conservation of Nature and Natural Resources, 2018). Possible measures to protect these species are mainly designed around access restrictions and the prohibition of climbing in areas close to where the birds are nesting. Such restrictions must be decided by the respective municipalities and Préfectures, where the PNR acts as a consultant offering recommendations and advice (personal communication Ms. Bourlon, PNR).

Also involved in the forest management of wild game is the Hunting Federation of Vaucluse which facilitates the different hunting associations of the region. In addition to utilizing hunting to regulate game population, hunters intervene in the territory in several ways, including the management of the environment by making the vegetation more favorable to the habitat of local rabbits (Federation Of Hunters Of Vaucluse, 2015). They also bring game feed into natural spaces depending on the level of natural resources (e.g. nuts). For some species this is regulated by the law (e.g. wild boar), but not for others (e.g. rabbit). The Federation wants to keep the wild boar on the mountains by feeding it there so that it does not cause damage to fields down in the valley since they are responsible for the compensation of damages on agricultural lands (personal communication Mr. Robert, Federation of Hunters Vaucluse). However, according to the PNR, feeding wild game has a higher probability of being inefficient as it contributes to an increase in population and stresses the natural food stores, leading to the intrusion into the agricultural fields. A PNR agent added that there are so many wild boars that hunters are currently not able to regulate their population effectively (personal communication Mr. Berson, PNR). 

Other primary concerns are fire management, as well as coordinating the shepherds’ visits to the mountains and forests. These concerns are linked as grazing by sheep is a natural way of keeping down the undergrowth that promotes fire within the region (personal communication Ms. Bourlon, PNR). Fire is both a threat and a requirement, as some species of pine need fire for the release of their seeds which assists in the biodiversity of the region, yet an unchecked fire can spread quickly and cause severe damage to the environment. Another difficulty with the management of sheep within the cedar forest comes from the various stakeholder interests, since the sheep farmers may want to have more grazing areas whereas forest owners may want more trees. Due to these issues, mediation and organization are some of the primary roles of the PNR (personal communication, Ms. Bourlon, PNR). 

NATURA 2000 Sites

Figure 2  Le reseau Natura 2000, Source: (Parc Naturel Regional du Luberon, 2017)

Nine Natura 2000 sites are present in the park region, seven of them being managed by the PNR and two of them being managed by a union, the Syndicat Mixte d’Aménagement de la Vallée de la Durance (SMAVD, 2018). Seven park rangers employed by the PNR manage the Natura 2000 areas in the Luberon region. Thus two different actors are managing the sites, which could lead to a problem of communication. The Natura 2000 sites are based on a former EU Habitat Directive, the funding of which in the region is estimated to be around 1.5 million Euros of subsidies to farmers for pasture management, and 1.3 million Euros of subsidies to farmers for management of the local water quality by reducing the application of fertilizer and pesticides. Fifty farmers, accounting for 1,000 ha (of a total area of 10,000 ha) take part in this project (personal communication Mr. Berson, PNR). The Durance River is engaged in this network thanks to its birds species richness and natural habitats (SMAVD, 2018).

The biggest Natura 2000 area in the region (see map: Pink area) is dedicated to bat protection. Bats are the only protected species outside of the Special Protected Areas which is in this region (personal communication Mr. Berson, PNR). The Special Bird Protection Areas and Special Areas of Protection (part of the EU Habitats Directive) account for only a small part of the overall Natura 2000 area in the Luberon. These are areas where certain species are protected to prevent their extinction. Subsidies from the EU can be used for nature protection in this area by managing hedgerows, reducing annual meadow cuttings, monitoring bat populations, and/or the creation and management of flower strips. As bats are an umbrella species, their protection is considered to also preserve the habitats of a larger ecosystem creating a species-rich agricultural landscape. Currently, annual monitoring of the eighteen regional bat species has revealed a decrease in the bat-population (personal communication Mr. Berson, PNR) believed to be caused by the following:

• disappearance of grassland at the benefit of more profitable productions such as lavender,
• purchase of land and old cabins by rich people to have secondary residences,
• antibiotics in animal husbandry (personal communication Mr. Berson, PNR).

Currently the PNR is working with the local farmers and landowners on ways to mitigate these issues.

Agrobiodiversity

Figure 3  Photo of the landscape overview site, Source: (Lucie LOMBARD, personal source) 

A diversity of land uses are present in the Luberon (Figure 3) and are predominantly linked to the elevation. Villages are either on the slopes of the mountains or away from the river, as the valley is used for agricultural activities, where the soil is more fertile. This leads to zones of biodiversity, with the mountainous regions focusing on forestry, silvopastoralism, and wildlife management and the valleys focusing on agricultural production.

One important site for biodiversity conservation within the PNR is the Maison de la Biodiversité (“Biodiversity House”). The Maison de la Biodiversité conserves 420 old fruit tree varieties representing 16 species. One of their missions is the education of diverse audiences about old varieties and domestic biodiversity. They also advise local farmers and municipalities, as well as offer internships about grafting, pruning and/or fertilization. Funding for the Maison comes from the commune of Manosque, the Region Provence-Alpes-Côte-d’Azur, the French Départements of Vaucluse and of Alpes-de-Haute-Provence, however, the Maison still lacks adequate finances and manpower as there are only three employees of the PNR managing the 10-11 hectares of orchard in addition to organising visits and participating in local and national events about old varieties. Maison de la Biodiversité is working in collaboration with various stakeholders, including an apiculturist that has beehives on site.

Past activities to promote biodiversity in the region included giving grafts of old varieties to farmers for free; however, the Maison’s current lack of funding makes this impossible to continue. A current concern is how to instil an interest in farmers in growing these older varieties. One problem the Maison faces is trying to alter current consumer demands for identical looking fruit towards more interest in natural looking fruit. With the GRAB (the regional research centre for organic productions) they are working on the FRUITNOV project in order to find interesting varieties for farmers in terms of resistance, hardiness, yield, taste, visual aspect and conservation (personal communication Mr. Nahal, PNR). 

Another location that is working towards agrobiodiversity is the Jardin Conservatoire des Plantes Tinctoriales which is located in the village of Lauris on “seven terraces spread over a height of 40 meters” (Couleur Garance, n.d.) of Lauris Castle. The Couleur Garance cultivates over 250 species of plants, including local regional plants traditionally used in the area for cloth dye. These include madder (garance) which was “widely cultivated on the plains of the Durance…to produce…red” (Couleur Garance, n.d.) and from the Luberon mountains, the buckthorn and smoketree plants. Although the facility is currently staffed by a small number of employees and volunteers, the garden continues educational outreach programs on the growth and use of these various colours and the sustainable manufacturing of natural dyes. A focus on the chemical composition and potential research benefits of the various plants is another focus of the garden and one that they are hoping to continue in the future (Couleur Garance, n.d.). 

Management of biodiversity on farms and agricultural land use

Agriculture is the second largest activity after tourism in the area. According to the PNR, 2,000 farmers are present in the region as of the 2010 General Agriculture Census. Thus, they represent around 8% of the working population. However, the number of farms is decreasing; around 17% of the agricultural surface area has been lost between 2000 and 2010 in favour of urban areas and secondary residences (personal communication with Ms. Charles, PNR). The area is a favourite destination for French as well as international visitors because of the pleasant and picturesque towns and villages, comfortable way of life, agricultural wealth, historical and cultural associations as well as hiking trails (Parc Naturel Regional du Luberon, 2017). This causes the total number of inhabitants in the region to vary greatly between summer and winter, due to the influx of tourists during the warm season, but it also drives up the costs of land.

Due to the change in land use in the region, the PNR is reflecting on how best to conserve territories and create protected zones (personal communication Ms. Charles, PNR). Another opportunity to improve wildlife habitats comes from the Hunting Federation which, in cooperation with the farmer/hunter network called Agrifaune, was working to implement or test agroecological measures on fields (hedges, cover cropping, etc.). Unfortunately, the Federation says they currently lack the staff to continue working with Agrifaune (personal communication Mr. Robert, Federation of Hunters Vaucluse).

Of the various agricultural land uses, organic farming has received a huge expansion. The region is the first in terms of organic surfaces. Indeed, organic farming represents 20% of the agricultural surfaces in the territory. Moreover, agriculture in the Luberon is represented by diverse products including: cereals, vine, arboriculture, market gardening and livestock (personal communication with Ms. Charles, PNR). 

Figure 4  Figure of the transect drive with the different land uses observed, Source: (Google Maps, 2018) 

To discover the general land use in the region, the group drove 1.5 km along a secondary road in Saint-Saturnin-lès-Apt (Figure 4) and listed the various land uses observed in a transect drive. Of the 45 land uses, 7 contained olive trees, 10 contained grapes, 6 contained cherries, 9 contained trees (mainly oak) or hedges, 5 were fallow fields, 6 contained housing or buildings, and 1 contained lavender. The predominant land use observed was grapes (22%), with trees (20%), olive (15%), and cherries (13%) coming in close behind. This is similar, but not exact with the 2012 listing of crops from the QGIS data from the Corine Land Cover EU-database that shows vineyards cover 13% of the available agricultural land and orchards cover around 4% (ISARA, 2018). The group determined the difference to be in the six year difference between the QGIS data and the observation. The predominant trees in the area are white and live Oaks, which were planted for a variety of uses, including wood, soil erosion control, and truffle growing. 

One of the projects the PNR works on with local farmers is organizing and hosting seminars where they explain and assist with the paperwork surrounding applying for European Union subsidies. Two types of special EU funds can be obtained for biodiversity management projects are subsidies for practices and subsidies for results (ex. of projects: forest management, pastoralism, research, biodiversity monitoring, etc.) (personal communication Mr. Berson, PNR). In case of unlawful activities or the breaking of the contract the farmer signed with the PNR, the farmer does not receive funding. The control of the farms however, is not carried out by the PNR, but by a Common Agricultural Policy (CAP) controller. Currently, subsidies are not linked to the administration of medications given to livestock. According to the park manager, the effect on the ecosystem caused by the medication should instead be part of the best practices catalogue which the PNR is devising (personal communication Mr. Berson, PNR). Therefore, the work of the PNR is highly linked to agriculture and to the regional farmers.

The PNR managed parks also host a “great species richness” (Gasc et al. 2010) of threatened arable weeds, e.g. messicoles (messis “harvest” and colere “to live” in Latin) compared to other regions with more intensive agriculture. These plants are “only found in extensive cereal crops” (Gasc et al. 2010) where they grow in open areas and mainly in cereal fields because of the similar life cycle and other favourable conditions offered by the crop production method (eg. in the Luberon: low-input farming, annual ploughing, sowing the previous-year-harvested seed and seed exchanges (ie. dissemination)). These methods can be either favourable or unfavourable depending on the goal. For example, small-scale crop-livestock agricultural systems seem to be the most favourable systems for these plants due to the natural dissemination of seeds via the animals’ fur or digestion. Non-favourable conditions include the use of herbicides, chemicals, and seed sorting, which is a particular concern for organic agricultural systems because of the efficient sorting of the seeds which are re-sown in the following seasons. Options for farmers to promote biodiversity within meadows include a national contest that farmers can take part in (“Concours des prairies fleuries”) where they either cultivate natural plant varieties or sow meadows with local varieties of flowers, herbs, and weeds.

While the Western portion of the Luberon is predominantly for crop production, the Eastern part focuses on livestock production (see Annex 2) (personal communication with Ms. Bourlon, PNR). Small ungulates (sheep, goat) are the main livestock produced in the park, due to the animal’s ability to survive under low water availability, which is a factor in the region. To assess the biodiversity and management of these animals the Biodiversity group visited livestock farms and a dairy cooperative.

Gaec de la Sizampe is a 400+ year old sheep farm that has known several changes in their production systems. Nowadays, owner Julien Bonnet and his wife have 600 sheep and sell meat using the Red Label. A conversion to Organic Farming is currently in progress across their 300 hectare farm. While the primary use of the sheep is for meat, he also works with other farmers in the region to manage the genetic diversity by bringing in rams from other farms to service his ewes for 3-4 years before once again exchanging with his neighbors. This natural-breeding method allows for genetic diversity and close ties between the farms. Unfortunately, wolves have been migrating back into the region from the Alps, which is a major concern for Mr. Bonnet. Although the farm has an electric fence to protect the sheep, he still has a problem with wolf attacks. To manage this, the Mr. Bonnet has hired a shepherd and has three different dogs, two specifically bred for wolf determent. Another problem caused by the wolves is that his livestock stays closer to the farm, which means that the land farther away, especially the forest, is left unused and the grasses close to the barn are being overgrazed. While there is a subsidy the farmer can apply for from the region to assist with the additional cost of hiring a shepherd, it only covers 80% of the shepherd’s salary up to a certain amount and is dependent of the size of the herd. 

On the other side of the livestock supply chain is the Fromagerie de Banon, a cheese cooperative in the area. Their aim is to produce and promote the traditional “Banon” Protected Designation of Origin Cheese outside of the region (Fromagerie de Banon, 2018). The cooperative is currently working with six farmers within the Banon region and one from the surrounding region. As part of the traditional techniques, cooperative members are required to keep their goats on pasturage for at least 200 days a year and are limited in the number of goats they can stock per hectare, depending on the type of land (10 goats for meadows, 3 goats on natural forage zones). The focus on quality and tradition as well as a thorough understanding of the local climate leads to farmers being highly aware of the biodiversity of their fields and the extensive use of the three traditional goats breeds for the region: Saanen, Le Rove, and Alpine (Slow Food, n.d.). 

Discussion

SWOT Analysis

By combining the various stakeholders shown within Table 1 (see Table 1 in Results) with the SWOT Analysis (Strengths, Weaknesses, Opportunities, and Threats) above (see Table 2), the group has come to the conclusion that the Luberon has the potential to be an Agroecological Territory since the PNR is the only stakeholder whose major function is to manage biodiversity in the region. 

SWOT is divided into two sections: Strengths/Weaknesses and Opportunities/Threats. “Strengths and Weaknesses are considered to be internal factors over which [an organization has] some measure of control. [Whereas,] Opportunities and Threats are considered to be external factors” (Juneja, n.d.). 

As agriculture is covering a large part of the  Luberon, it must also contribute to the management of the natural heritage in the region. Since the regulative power mainly belongs to the municipalities, or in terms of agriculture, to the private owner, the PNR is lacking the possibility to enforce sufficient nature conservation. In addition, the PNR has no proper budget to manage their own activities, which makes them highly dependent on EU subsidies. The financial resources also affect the manpower, which is not sufficient to manage the whole PNR area. Apart from the PNR not being able to physically manage the whole Park area, the employees are also confronted with many different stakeholders and their individual interests. There is a twofold dependency on the municipality as the Park Charter is ratified every 12 years. During the ratification, the PNR is depending on the municipalities and their residents to swear to continue to participate and help legislate the park’s many activities. 

One such agri-environmental measure in the Luberon allows pastoralism to conserve “rare and sensitive biotopes” (Beylier et al, 2002). This measure was led by the PNR as is one of the most important goals of the organisation to protect these areas. However some conflicts between the different stakeholders have been identified such as:

• with hunters: for example, feeding spots in the pasture can compromise the herd movement, hunting dogs can represent a danger for the sheep, reproduction period of game and grazing period overlap and can lead to a disturbance of the reproductive activity of game;
• with the landscape management: visual impact of sheep pens;
• with forest management: prohibited grazing in certain areas where trees are replanted;
• with biodiversity management: the grazing period may overlap with the reproduction of some rare species (Beylier et al, 2002).

Thus, biodiversity management involves many stakeholders. It is also the case in the “mediterranean-mountain grassy areas” on the ridges of the Luberon which are hotspots of biodiversity. They are unique because of the location, the ecological conditions and the pastoralism which has taken place for centuries (Garde et al. 2011). They are also unique because they have been managed in late spring for at least 50 years (Lasseur et al., 2010, cited in Garde et al. 2011), which is different than normal pasture systems where livestock is grazed close to the farms in early spring and in the higher mountains in summer. However, the ridges are currently threatened by changes in grazing practices, the erosion caused by motor vehicles, the damages of wild boars, and current climatic incidents. 

Current grazing practices have changed: the animals are kept less tightly, because of the spread of the herd, they eat more heterogeneous vegetation and they do not eat most of the available resources (Lécrivain, 2007). Linked to this, two points of view differ. On one hand there are pastoralists and Sophie Bourlon, a person of the PNR we met during the excursion, who advise to keep the animals more tightly and to shorten the grazing period at the same place, for the renewal of the vegetation. On the other hand there are “environmentalist practitioners” who advise more extensive grazing (Garde et al. 2011). In the last decades, pastoralism has decreased leading to the development of scrub and resinous trees which is considered as a “threat for the sustainability of the landscape” (Beylier et al, 2002). Regional farmer Mr. Bonnet has stated that “sheep farming is hardly financially viable and highly dependent on governmental subsidies” (personal communication Mr. Bonnet). In the past years, the PNR was not able to hire sheep farmers to graze the hillsides, linked to the decreasing number of sheep farmers in the region. The comeback of the wolf in the Luberon region leads to further problems for the local livestock farmers. The PNR has difficulties in managing the arrangement between nature (wolf) and agriculture (farmer), which could eventually lead to discontent among livestock farmers. Even if grazing is one factor influencing the vegetation’s biodiversity, there are other factors difficult to work out such as climate change (Garde et al., 2011). On areas which have been protected from grazing for more than 30 years, important changes started to appear in the 1970s and 1980s. Climate change is presumed to be the main factor influencing the vegetation’s biodiversity. Because the ridges of the Luberon are the last alpine reliefs in the South of France, they can be sentinels of climate change for ecosystems in the transition zones between Mediterranean and Alpine ecologies. “Alpages sentinelles” is a French research project started around 15 years ago, when important droughts happened during summer and implemented in 37 alpine pasture farms (IRSTEA, 2018). Anthropogenic factors also influence open grassy areas, as do the increasing population of wild boars. Garde et al., 2011, advise creating a reasoned hunt plan to manage the boar population.

During the group’s transect drive through the valley, smaller family farm plots predominated the landscape, while many of the plots contained homes or were surrounding small clusters of homes (neighborhoods). Since many homes are purchased in the region as secondary or vacation homes, these smaller plots of land make sense. The cost of purchasing land has increased over the past few years according to farmers the group spoke to; a hectare of bare earth now costs 15,000E on average but it can go up to 100,000E depending on the area and water access. The difficulty that farmers have in purchasing additional land can be viewed as both a threat and an opportunity. Obviously not being able to purchase consecutive pieces of land makes it more difficult to farm large parcels and may cause the farmers to travel a larger distance to get to their various plots, however, breaking up large monocrops into smaller sections can also increase the biodiversity of a region and allow for more transition zones between crops which increases habitats for insects, birds, bats, and small animals. The latter being one of the goals the PNR managers espoused during the groups’ interview.

Conclusions

Research Question 1: Contribution of different Stakeholders (see Table 1)

Park employees in charge of natural areas management work in defined departments within the PNR, but some of them work on multiple topics (bats, silvopastoralism, forestry, etc.) while others focus on specific missions (e.g. Maison de la Biodiversité). Additionally, the PNR collaborates with different stakeholders which have more specific actions on biodiversity. Farmers affect biodiversity and landscape use with their practices on their fields and pastures, with the genetic diversity of their livestock, and when they graze the forests. Hunters regulate wild animal populations and manage some of the vegetation and forest owners (including private owners and ONF), maintain and harvest the forest.

Research Question 2: SWOT Analysis of Park Initiatives: (see Table 2)

Although the PNR initiates a lot of biodiversity measures in the agricultural landscape, keystone species (specifically bats) have experienced a decrease in numbers over the last few years. Even in Special Protected Areas the biodiversity is decreasing. Species of interest, like the Egyptian Vulture or Bonelli’s Eagle, are locally threatened with extinction (only five vulture couples and one eagle pair remain). In terms of the park’s capacity, the measures implemented by the PNR are quite appropriate. The PNR is dealing with the relevant issues, such as sensibilisation, species protection, agricultural best practices and subsidy incentives. Unfortunately, the PNR suffers from its legal limitations and dependency on additional stakeholders. Therefore, the PNR is not capable of dealing properly with the biodiversity decrease. To change the overall issues, a general rethinking of biodiversity protection and the agricultural sector is necessary. This includes measures on the expansion of sustainable agriculture, international protection legislation and a change in consumption behaviour by consumers.

Limitations of the Research

While the group worked together well, there were certain inherent limitations within the overall project design. Having only three full days and two half days to interview the various stakeholders was a very large limitation, as the group only had the opportunity to speak to a handful of organizations. The group managed some of the constraints by utilizing a phone call interview with the hunting federation,  but a lack of meeting times and potential resources was a hindrance (ex. some of the meetings were canceled and some locations did not have people available to speak to). Other limitations included proper time for the group to ask specific management technique questions, so the overall feeling is one of general knowledge about the organizations, but no real specific information as to how they feel or complete their daily tasks for biodiversity management.

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IRSTEA, 2018. Sentinel mountain pastures. [Online] Available at: http://m.irstea.fr/linstitut/alpages-sentinelles [Accessed 2 October 2018].

ISARA, 2018. QGIS Luberon Isar@Net. [Online] Available at: https://isaranet.fr/. [Accessed 3 October 2018].

Juneja, P., n.d. SWOT Analysis - Definition, Advantages and Limitations. [Online]

Available at: https://www.managementstudyguide.com/swot-analysis.htm [Accessed 5 October 2018].

Lasseur, J., Bataille, J.E., Beylier, B., Etienne, M., Legeard, J.P. & Luccioni, J. (2010). Modélisation des relations entre dynamiques des territoires et des systèmes d'élevage dans le massif du Luberon. Cahiers d’agriculture, vol. 19, n°2, Élevages extensifs et territoires, 90, 96. 

Lécrivain, E. (2007). Le gardiennage des ovins : des savoir-faire adaptés au comportement des animaux et à l’entretien de l'espace. Courrier scientifique du Parc naturel régional du Luberon, 8, 28–41.

National Museum of Natural History, 2018. The Sorgue and the Auzon. [Online] Available at: https://inpn.mnhn.fr/site/natura2000/FR9301578 [Accessed 2 October 2018].

Office de Tourisme Luberon Monts de Vaucluse, n.d. Luberon Regional Nature Park. [Online] Available at: http://www.luberoncoeurdeprovence.com/en/out-and-about/luberon-regional-nature-park [Accessed 2 October 2018]. 

Parc Naturel Regional du Luberon, 2017. Natura 2000 in the Luberon. [Online] Available at: https://www.parcduluberon.fr/un-territoire-en-action/natura-2000-r1/natura-2000-luberon/ [Accessed 2 October 2018].

Parc Naturel Regional du Luberon, 2018. Bilan de l'animation du site. [Online]

Available at: https://www.parcduluberon.fr/wp-content/uploads/2018/01/bilananimation_petitluberon_mai2016_avril2017.pdf [Accessed 3 October 2018]

Slow Food, n.d. Slow Food Foundation for Biodiversity. [Online] Available at: https://www.fondazioneslowfood.com/en/ark-of-taste-slow-food/communes-provencales-goat-banon/ [Accessed 1 October 2018].

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Available at: https://www.smavd.org/la-gestion-de-la-riviere/natura-2000/  [Accessed 4 October 2018].

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UNESCO, 2018. Biodiversity. [Online] Available at: https://en.unesco.org/themes/education-sustainable-development/biodiversity  [Accessed 4 October 2018].

Interviewed people:

Berson Mathieu, PNR Natura 2000 and Agro-environment, interviewed 26 September 2018 at Plateau des Vachères

Bonnet Julien, sheep and lavender farm, GAEC de la Sizampe, Les Crozats

Bourlon Sophie, PNR Natura 2000, interviewed 28 September 2018 in the Cedar Forest, Bonnieux

Charles Nathalie, PNR Agriculture Service, interviewed 24 September 2018 at Maison du Parc, Apt

Nahal Mohamed, PNR Maison de la Biodiversité Manosque, interviewed 26 September 2018 at Maison de la Biodiversité, Manosque 

Robert Guillaume, Federation of Hunters Vaucluse, interviewed by phone call 27 September 2018

Annex 1: Questionnaire

General questions:

• What type of biodiversity are you managing or preserving?
• What do you do concretely to preserve biodiversity?
• What are the difficulties that you face to preserve biodiversity?
• Do you cooperate with other stakeholders to preserve biodiversity? 
• What is your evaluation of the state of the biodiversity in the area? Do you think Luberon is better than surrounding areas for biodiversity ? 

Park manager:

• What is the organization of the parks management (who manages what)?
• How do you manage communication between the different parc groups: Natura 2000, UNESCO, Geopark, PRN, farmers, municipalities, tourists, etc.? 
• Who are the primary stakeholders and policy makers related to biodiversity management?
• Do you cooperate with other stakeholders to preserve biodiversity?
• Do you participate to research programmes, experimentations?
• How do you judge funds, labour force, legislative power to implement your project and to interact with other stakeholders?
• Are there certain overall rules or regulations that you must follow from the government or are the rules from a local organization?
• According to you, how well are the regulations for biodiversity protection respected by stakeholders (municipalities, companies, farmers, hunters, tourists, citizens, …)?
• Do you think some parts of the charter should be changed?
• Biodiversity management
• Are there specific initiatives or practices that are typical on Luberon farms? Do you know if farmers in Luberon make special effort to preserve biodiversity (Concours des prairies fleuries) ? 
• How do you measure and monitor the state of biodiversity?
• What are the keystone species of the different habitats? Are there any special animals or plants that you are managing? How are you doing this? What are the biggest concerns?
• Do you use animals for landscape management? 
• Are there any invasive species that you are struggling with? What are you doing to manage them?
• Are there areas which have never been managed or cultivated? Are there areas with few human activities?
• Do you seek to expand natural/wild spaces? 
• Is there poaching? How do you manage this?
• Does tourism have an impact on biodiversity conservation? How do you manage ecotourism? Do you have any issues? Does it play an important role in your finances? 
• If we have time:
• How do you manage seed saving, cuttings, or distribution of the plants? 
• What are the primary ways you manage diseases within the park of animals and plants?
• How has the climate/weather changed in the last 5 years? What do you think will change in the next 5 years?
• Are there any animal corridors that you manage? How?
• How do you manage roadways, hedges, waterways, etc?

Farmers - sheep farmer :
Biodiversity

• How many different types (breed) of animals do you raise? 
• What is the genetic diversity of your animals? Do you raise your own males or do you use a service? Do you raise old breeds? 
• How many different plants (for animal feed and/or human consumption) do you grow? Any old varieties? How do you decide which plants to grow? 

Practices

• What is your management technique for your pasturage? 
• Do you manage the hedges, trees, roadways, etc? If so, how do you manage these?
• Do you rely more on artificial inputs (machines, chemicals, …) or on organic or natural inputs such as soil fertility, pollination, auxiliary insects, etc. for production?
• Do you consider allowing more biodiversity on your farm in the coming years (more hedges, stop pesticides/tilling, enhanced rotations, …)?
• Are there specific initiatives or practices that are typical on Luberon farms?
• Do you know if farmers in Luberon make special effort to preserve biodiversity (e.g Concours des prairies fleuries) ? 

Wildlife, wolf

• How do nature conservation and wildlife impact your farm?
• Have you had some damages because of the wolf? Does it change your practises for pasture management? (+ or - point of view) 

Hunting federation:

• What are the primary animals that are hunted in this region? Birds? 
• Have you seen an increase in damage from the games, specifically wild boar? Can you explain how you manage compensations? Are there a lot of damages on trees because of games? 
• Do you feed the games? 
• Is there a market for local wild caught game? (To be able to sell)
• Do you think the quotas are high enough or are there any quotas do you think should be changed and why? 
• How involved is the federation in forest and park management?
• Can you explain your relationship with the Agrifaune? 
• How prepared are you for the African Swine Virus? How are you managing it? (peste porcine africaine)
• What’s your stake on the Wolf? Do you manage damages from wolves? How do you manage them?
• Which is more popular, sustainable, between bow or gun?

Maison de la Biodiversité:

• What is your major objective here with the Maison de la Biod.?
• Who are the primary stakeholders and policy makers at the Maison de la Biodiversité?
• Do you have enough funds, labour force, legislative power to implement your project and to control other stakeholders?
• Are there certain overall rules or regulations that you must follow from the government or are the rules from a local organization?
• According to you, how well are the regulations for biodiversity protection respected by stakeholders (municipalities, companies, farmers, hunters, tourists, citizens, …)? 
• Are there any special animals or plants that you are managing? How are you doing this? What are the biggest concerns? Are some species extinct? If yes, which ones?
• How do you manage seed saving, cuttings, or distribution of the plants?
• Do you try to spread old varieties, to produce them again?
• Are there any invasive species that you are struggling with? What are you doing to manage them?
• Does tourism have an impact on biodiversity conservation? How do you manage tourism? Do you have any issues? 
• How has the climate/weather changed in the last 5 years? What do you think will change in the next 5 years?

Cedar forest

• Why was it planted? Is it public, private forest? Who is managing? How is it managed? 
• Where the wood is sold? For which uses?
• Which special kind of biodiversity is linked to the cedrus forest? Are there endemic species? 
• How is it with conservation? 
• Can you explain the fire management? 

Annex 2 : Map of the PNR : land cover and topography

Utilization of Wetlands for Agricultural Drainage Treatment: A Literature Review

Utilization of Wetlands for Agricultural Drainage Treatment: A Literature Review
By: Tamisan Latherow
October 2018

Grade B+
Abstract:

Wetlands are gaining popularity for use in agricultural waste treatments due to their natural ability to filter and fix excess nutrients, pesticides and herbicides, raising their ecosystem service valorization. With Nitrogen removal rates between 14-95% and Phosphorous removal rates between 25-95%, depending on design and infrastructure, wetlands provide a valuable tool for agricultural landscape management. However, those same services may be compromised if residence time and biodiversity of plants and microbial species are not properly managed. Mitigation efforts for restored wetlands surrounding agricultural landscapes must therefore be the primary goal of constructed wetlands for use in waste treatment and beneficial ecosystem services.

Introduction:

The world population is expected to reach 9.8 billion by 2050 (United Nations, 2017). Current estimates are that, barring all other considerations, 30% more food will need to be produced to feed everyone (Wezel, et al., 2014). To this end, many studies are focused on the creation of more food or the allocation of resources to manage supply chains, however, one must also consider the actual soil this food is to be grown on and the geospatial relationship to the surrounding landforms, catchments, and agricultural processes. How these systems interact and their influence down-stream directly impacts the efficiency of the lands’ ecosystem services, especially in wetlands. 

The Convention on Wetlands, aka. the Ramsar Convention, define wetlands as “areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres” (Ramsar Convention Secretariat, 2016). According to Ramsar, wetlands cover roughly 6% of the Earth’s surface and ecosystem services of wetlands includes water and nutrient filtration and fixation, animal nurseries and habitats, storm surge protection, erosion and soil control, and natural locations of primary food stores such as rice and fish (Secretariat of the Convention on Biological Diversity, 2015). 

Wetlands have been incorporated into agricultural land use for generations and include traditional farming practices such as rice paddies, aquaculture, terraces, and reed production for fiber (Verhoeven & Settler, 2010). Much of the world’s wetlands have either been converted to and/or border agricultural lands (Davidson, 2014) and since they are typically at a lower elevation where the natural flow of catchment systems deposit soil from upstream they are often the recipients of fertilizer run-off (Yu, et al., 2018). 

Methods:

An analysis of wetlands and their relationship to agriculture was performed utilizing over twenty articles in published scientific journals across multiple disciplines (agriculture, ecology, economics, engineering, marine and freshwater ecosystems, botany and biology). These articles covered several different spatial scales, ranging from individual wetlands to national, regional, and global wetland overviews for the past few years. They also cover both natural (limited human alterations) and constructed (man-made) wetlands, hereafter referred to as NW or CW. The articles were broken down into three categories for further review: Nitrogen, Phosphorus, and herbicide and pesticide sequestration and then discussed under the subtopic of Ecosystem Services. All were reviewed at the landscape scale of application of agroecological practice and fall under the subheading of management of landscape elements (Wezel, et al., 2014).

For the purpose of this review, agroecological processes are those agricultural processes designed to produce significant amounts of food that also follow the natural cycles of the surrounding ecosystem for such items as nutrient cycling, natural pest management, soil and water conservation, biodiversity conservation, biological N fixation, carbon sequestration, and bacteria formation and management (Wezel, et al., 2014). To quantify the data around these topics, an agroecological framework is needed. 

The framework designed by Hill and MacRae (1996) was the base for this analysis with alterations by Wezel, et al. (2014). The framework focuses on efficiency increase, substitution practices, and redesign (Wezel, et al., 2014). Within these three pillars, Wezel, et al. identify specific practices related to crops and landscapes as well as three levels of management, those being the field level, farm level, and landscape level (Wezel, et al., 2014). We shall be looking at the agricultural landscape, specifically at if the addition of wetlands [either natural (NW) or constructed (CW)] for agricultural drainage treatment benefits or hinders the wetland’s natural ecosystem services. Wetlands were chosen due to their natural filtration ability and for the fact that 64-71% of wetlands have been lost since 1900 A.D. due to anthropogenic drivers such as agriculture (Davidson, 2014). 

Results:

Various studies (Dal Ferro, et al., 2018; Darwiche-Criado, et al., 2017; Ewing, et al., 2012; Kasak, et al., 2018) have been performed to identify the amount and efficiency of wetlands to manage fertilizer run-off from agricultural lands-Nitrogen (N) and Phosphorus (P) being the two predominant chemical elements; however various herbicides and pesticides have also been studied. With the growth of industrialized agriculture and the demand for more food, fertilizer treatments have increased. However, poorly -timed applications of these fertilizers account for much of the nutrient run-off into surrounding water sources and causes algae blooms, Eutrophication, and degradation of water quality (Kasak, et al., 2018). The wetland/catchment ratio creates two types of surface flow: in-stream and off-stream (Kasak, et al., 2018). The difference between in-stream (CWs located in the flow path of the drainage water, such as a river or ditch) and off-stream (where only part of the water flows through the CW) directly impacts the efficiency of the wetland to mitigate run-off levels. Generally, the ratio of wetland to catchment should be 0.5% with a relatively low flow velocity to allow the sedimentation of nutrients and soil run-off (Kasak, et al., 2018). 

Nitrogen and Phosphorus Sequestration

The three main ways nitrogen is taken up by an ecosystem is through vegetative uptake, sedimentation, and denitrification. Natural wetlands have been shown to retain around 64% of the Total Nitrogen loading (Saunders & Kalff, 2001), but in agricultural areas, TN appears mainly as nitrate, which is not as affected by sedimentation in high flow areas. In areas with lower flow or high plant coverage, where the roots of the plants allow for higher rates of denitrification and sedimentation and contribute to a higher residence time, an increase in the rate of retention can be found (Saunders & Kalff, 2001). Most agricultural associated wetlands are off-stream systems since water inundation leads to root rot in many crops while most aquaculture activities (such as rice farming) are conducted in-stream.  The natural formation of the wetland (eg. depressions, river banks, soil type, etc.) and the density of vegetation affects the sedimentation of solids and minimizes the transport of nutrients (Uwimana, et al., 2018). 

The increase in flow rate in in-stream systems minimizes the amount of time nutrients and soil has to settle and start filtering through the wetland soil stratus (Kasak, et al., 2018). In a NW this filtration happens through several layers of soil and aggregate before reaching the groundwater and is assisted by the various natural elements in the wetland such as cattails (Typhus), willows (Salix), and other plants, as well as microbial and fungi systems. In a CW, these same processes are managed by various liners and sedimentation ponds, some of which may be planted with vegetation. Most sedimentation ponds vary in the time water flows through the system from a few hours to a few weeks whereas a NW can take years to fully filter (Kasak, et al., 2018).

Nitrogen removal is dependent on many factors, but the most important are temperature, oxygen and carbon concentrations since they contribute to the various chemical (ammonification/volatilization) and microbial functions (nitrification/denitrification) (Kasak, et al., 2018). Factors such as groundwater seepage, plant-biomass N accumulation, and oxygen stratification within the water may affect the potential for N removal. These points were thought to contribute to the increase in NO₃-N concentration over the three-year study of the Kasak, et al. paper, where as the other papers saw a decrease in NO₃-N concentrations.

When evaluating nitrate-nitrogen loading capacity, the soil’s Total Carbon and pre-loading Total Nitrogen levels were also compared between organic and mineral soils. An earlier study by Ewing et al. (2012) found that organic soils had TC (29-35%) and TN (0.7–0.9%) while mineral soils had 6–7% and 0.2–0.3%, respectively (Messer, et al., 2017). This is important since the removal efficiency of N decreased when the TC/TN ratio approaches 5:1 (Messer, et al., 2017). The ratio is an indicator if enough oxygen occurred within the denitrification process, which accounts for 93% of nitrate uptake (Tournebize, et al., 2017). If there is a lack of oxygen, the conversion of nitrate into N2O (GHG) and N2 does not occur, causing overloads in the system. Flow rates and seasonality of rainfall and fertilizer application times, (Dal Ferro, et al., 2018) as well as the OM content of the wetland (Darwiche-Criado, et al., 2017), are direct contributors to this process. These issues can be mitigated by establishing a longer residence time within the CW system, allowing for more settling and the denitrification process to occur over a longer period. Diversified vegetation is also key since plants take up different amounts of nitrates over different parts of their life-cycle and a diversified vegetation profile within the wetland allows for the maximum amount (upwards of 7%) of nitrogen removal through this process  (Tournebize, et al., 2017). This is also assisted by the variation in the plant’s carbon storing capacity. For example, Nasturtium’s have been shown to support denitrification more fully than common reed (Phragmites) in wetland systems (Tournebize, et al., 2017). 

Likewise, Phosphorus retention is also dependent on water temperature and oxygen efficiency, microbial activity and plant uptake, however the retention rates for P average only around 14% when flow rates are at their lowest allowing for a longer standing residence time (flow rate of 5 L sˉ¹) (Kasak, et al., 2018). Of that 14%, 50-70% is found within the sediment and is considered as part of the permanent reservoir (Di Luca, et al., 2017). Plant uptake and microbial activity are directly linked to the pH, temperature and oxygen efficiency as plants and microbes are most active during warmer weather with access to appropriate oxygen stores for growth and development. Research by Johannesson, et al. (2017) shows a concern over other considerations such as peak flow times for grab sampling as differences in particulate phosphorous (PP) versus total phosphorus (TP) numbers and errors based on sampling during flow-events, that is, before, during, or after major flow events have arisen which could skew the amount of TP ratios (Johannesson, et al., 2017). These questions arise because of the seasonality in loading levels and their large impact on quantity of N and P in the system due to residence time and flushing of the wetlands.

In sediments, it has been shown that pH affects P absorption, as pH increases the absorption of phosphate decreases due to competition between absorption ratio of hydroxide (OH-) and soluble reactive phosphorus (the only form of P available for plant up-take) (Di Luca, et al., 2017). This decrease in oxidation-reduction potential (ability of water to cleanse or break-down waste) and the interference of OH- reduces the absorption of P into the sediment (Di Luca, et al., 2017). Since most P in wetlands is in insoluble organic or inorganic form (dominant ratios) (Bressler & Paul, 2015), the addition of nutrients into the CW and the subsequent loss of oxygen from Eutrophication can free phosphorus from the sediment and increase the TP available for plant uptake. However, the resulting change in C:P changes the microbial biomass and rate and variability in biodiversity within wetlands, which can lead to losses of biodiversity.

Herbicide and Pesticide Sequestration

Pesticides are often a factor after application and after heavy flow events such as storms; yet, they are often less than 0.5% of the applied application with rates rarely exceeding 3% (Tournebize, et al., 2017). This is three times less than found in nitrate levels, and is typically concentrated at the head of the in-flow region (up-stream of the watershed), however there is a wide variability in the transfer and transformation process surrounding each type of pesticide (Tournebize, et al., 2017).  The transfer process for pesticides from the water to the plant (28-55%) is of concern when the transfer moves not from water to plant, but from water to animals (especially marine animals) through tissue absorption (Tournebize, et al., 2017). There is also the issue of plant material where the chemicals have moved into the interior of the plant tissue through photoaccumulation and rereleased into the system upon decomposition (Tournebize, et al., 2017). Removal of these chemicals can sometimes be carried out via deabsorbion by flushing the system with more water, but it is not always effective. 

Transfer is not the only process pesticides can go through. New molecule creation from the dissolvement or degradation of the parent chemical can also occur through transformation and while the new chemicals are often in smaller quantities, they may be no less toxic. Transformation occurs predominantly in three ways within CWs: photodegradation (the effect of sun light), hydrolysis (via the movement of water), and biodegradation (through microbial processes) (Tournebize, et al., 2017). The primary agent of transformation is through microbial processes, specifically in aerobic conditions, where some chemicals such as the herbicide atrazine, widely used in corn and sugarcane production as a weed suppressant (Hayes, et al., 2010), have been shown to have mineralization rates upwards of 70-80% (Tournebize, et al., 2017). Mitigation strategies include permitting the water level to rise and drop to allow for oxygen to be starved from the system as well as sunlight to enter and assist in breaking down the chemicals further; this creates a combination of both reductive and oxidative conditions (Tournebize, et al., 2017). Less toxic chemical alternatives such as acetochlor and butachlor have been proven to degrade quicker in wetland environments (acetochlor in the rhizosphere and butachlor via microbial process) (Yu, et al., 2018), but the solubility of these chemicals is of concern. Acetocholr’s high water solubility makes it more prevalent in the water while butachlor’s low solubility leads to higher concentrations within the soil and subsoil. Simply changing to more easily degradable chemicals does not mitigate the effects if the ratios for chemical use increase; detection rates of 75-100% for acetochlor and 88.9-100% for butachlor within the surrounding wetlands were detected in the Chinese report (Yu, et al., 2018). Mitigation efforts to remove the herbicides are available and include increased growth of C. augustifolia plants to enrich soil microorganisms which can start to break down the chemicals. Butachlor can also be eliminated from the system by the removal of soil sediments (Yu, et al., 2018). 

In areas where organochlorines (OCPs) and DDT are used in agriculture, high concentrations of the OCPs have been found in tissue samples of fish species such as Tilapia and Catfish and have been linked to higher levels in secondary predators like birds and crocodiles, and even humans (Buah-Kwofie, et al., 2018). DDT use has been linked to eggshell thinning in aquatic birds and while the concentration levels are currently not at the level of human risk, according to EU regulations, further studies should be performed to find the threshold of consumed fish contaminants in the human population (Buah-Kwofie, et al., 2018).

Discussion:

Fig. 1. Ecological framework for landscape design on agricultural lands. “Arrows represent the main research axes and point towards the research frontiers. Darker shading indicates a greater level of current knowledge” (Landis, 2017).

While the methods for collecting data were similar across the research (water tests, biomass indexes, grab samples, etc.), percentages and ratios were not consistently presented making it difficult to evaluate across zones and papers. Future research would benefit from the creation and utilization of a general health assessment guide for wetlands such as the one created by the United States Environmental Protection Agency (Office of Water, U.S. Environmental Protection Agency, 2002). Generally, it was shown that wetlands do provide a valuable agricultural agency for the removal and dissipation of harmful agricultural runoff, as shown by the percentages in Table 1, however, there are key issues regarding if these same removals negatively affect the natural functionality of wetlands.

Table 1: Percentages of Removal and Plant Cover within Global Wetlands

Ecosystem Services Evaluation

The utilization of wetlands for waste treatment cannot be overstated, as it is clear from the research that their ability to remove large quantities of Nitrogen and Phosphorus as well as their potential for pesticide and herbicide removal is of great importance and benefit to the agricultural landscape. However, there are certain key components that should be noted and evaluated in further research including: temperature, seasonality, and pesticide management for denitrification purposes, buffer zones between wetlands and agricultural lands, plant biodiversity, and anthropogenic disturbances.
Denitrification effectiveness is a key aspect to the functionality of wetlands with temperature and dissolved oxygen being the two main components. High flow rates during flooding cause a slowing of denitrification and lack of oxygen into the system, whereas cycles of high water and low water with longer residence times and lower flow rates provide the greatest removal rates (Darwiche-Criado, et al., 2017). The combination of nitrates and pesticides within the system is a challenge for future studies, as certain chemicals (ex. Difenoconazole (fungicide),Deltamethrin (insecticide) and Ethofumesate (herbicide)) in high concentrations (500 mg/kg) have been shown to inhibit denitrifcation processes within the soil (Tournebize, et al., 2017).

Various studies (Buah-Kwofie, et al., 2018; Hayes, et al., 2010) have shown impacts of agricultural chemicals on the biodiversity of the down-stream systems including lakes and rivers. Fish and amphibian species provide a measure of the environmental exposure to the various chemicals due to their uptake structures: fish accumulate chemicals into their tissues and the amphibian’s skin allows for direct assimilation of chemicals via absorption. Fish have been shown to uptake 2-7% of pesticides into their flesh, up to 700% more than the surface soils these chemicals are actually sprayed on and chemicals like atrazine have been linked to the decline of global frog populations (Hayes, et al., 2010).

Mitigation strategies include planting crops that remove excess nitrates and phosphorus (such as corn) for several years between the primary agricultural zones and the wetlands (Ewing, et al., 2012) and planting narrow woodland buffer zones that would break up the flow of water and allow for greater species diversification of animals such as frogs (Sawatzky, et al., 2019). The two CW design methods (in-stream vs. off-stream) can also be utilized to mitigate each type of removal process. In-stream design methods that favor the removal of nitrates can be created where the CW is sufficiently broad allowing for generally equal spread of drainage water over the entire CW. Likewise, off-stream methods can be designed for pesticide removal. This is accomplished by the use of a gate to flood the land after pesticide use and direct the water into the CW. The gate is then closed after a set time allowing for higher residence time of effected waters in the CW (Tournebize, et al., 2017).

Plant biodiversity is another indicator of wetland health and ecosystem functionality. In a comparison between forested, agricultural, and urban wetlands, agricultural wetlands which were semi-permanently flooded with shallow water depth had the most biodiversity of plant species; 81.9% of which were herbs, ferns, or grasses (Moges, et al., 2017). Since plant uptake of N and P have been shown to account for 15-80% of Nitrogen and 24-80% of Phosphorus in the majority of research (Wu, et al., 2015), plant biodiversity and efficiency is of great concern. Anthropogenic factors such as harvesting, grazing, drainage, and waste treatment, while creating microhabitats, also disrupted the natural fauna and allowed for colonizer species which had the biggest effect on species diversification (Moges, et al., 2017). While this is of concern for seriously impaired wetlands, other ecosystem services have to be balanced for the good of the surrounding communities. In addition to aesthetic and recreational uses, many wetlands are used to support agricultural products and if taken into account with the activities, can greatly increase the perceived value of wetlands which may assist in their preservation or management. One such activity is mushroom production on common reed substrate harvested from wetlands.

It has been shown that Oyster Mushrooms grown on a reed substrate produce just as well if not better than on normal wood-shaving substrate and have the added benefit of removing small amounts of Nitrogen (2%), Phosphorus (0.2%), Potassium (1.34%), Pb and Cd from the wetlands through plant uptake (Hultberg, et al., 2018). The additional removal of heavy metals such as Lead (Pb) and Cadmium (Cd) assists with keeping the wetland water clearer for fish and more sensitive plants (Hultberg, et al., 2018). Another reed-focused activity is the creation of cattail (Typhus) pellets for use in wood burning stoves. These pellets have been shown to create between 7,266 and 8.551 BTU/lb which is comparable, if not better, than traditional wood pellets (7,266-7,739 BTU/lb) (Grosshans, et al., 2013) and convert roughly 0.7-0.11% Phosphorus, 0.79-1.53% Nitrogen, and 0.31-0.64% Potassium from the cattail’s dry weight (Grosshans, et al., 2015).

Overall, systems where traditional methods (that is non-fertilizer or chemical amendments) for farming that incorporate low-intensity crop production, grazing, and fish farming where the natural hydrology of the wetlands is left intact, may be the best choice for utilizing wetlands for both ecosystem services as well as economic viability (Verhoeven & Setter, 2010) for the surrounding communities.

Conclusion:

In conclusion, when looking at wetlands and their interaction with agricultural lands, ecology must co-exist with economics, and stakeholder engagement must be high for proper management of ecosystem services as well as economic viability. Wetlands used as landscape elements can benefit from low-intensity anthropogenic disturbances depending on temporal and spatial scales such as seasonality and mitigation efforts. The natural filtration ability of wetlands to remove fertilizers, pesticides and herbicides make constructing wetlands near agricultural lands highly economically viable, yet there are some key aspects of the ecosystem functions and biodiversity aspects that should be reviewed in more detail including the management of biodiversity within the wetlands for the greatest ecosystem service benefits. Overall, the research is clear that wetlands can be used for agricultural drainage treatment, but there is more uncertainty around if treatments negatively impact the very ecosystem services that those agricultural lands are counting on. Incorrect chemical loads and seasonal variability can greatly impact the efficiency of wetlands and should be taken into account when designing or utilizing CWs. The agroecological functionality of wetlands are tied to its hydrology, geomorphology, and biodiversity and these need to be key aspects of evaluation before utilization. 

Bibliography:

Bressler, D. W. & Paul, M. J., 2015. Effects of Eutrophication on Wetland Ecosystems, s.l.: Tetra Tech, Inc..

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