1. Please check and comment entries here.
Table of Contents

    Topic review

    Kettle Holes

    View times: 165
    Submitted by: Carsten Paul

    Definition

    Kettle holes are small water bodies of glacial origin which mostly occur in agricultural landscapes. While they supply numerous ecosystem services (ES), this supply may be negatively affected by agricultural management on surrounding fields.

    1. Introduction

    Agricultural landscapes supply multiple ecosystem services (ES) through interacting land uses and geobiophysical settings. These services are defined as the contributions of ecosystem structure and function (in combination with other inputs) to human well-being [1]. Sustainable agricultural management needs to account for site-specific characteristics, including topographic factors and coexisting biotopes. In this regard, a particular challenge to sustainable management arises where fields include kettle holes. Kettle holes are pond-like, depressional wetlands in young moraine landscapes. The term ‘‘kettle holes’’ is preferably used in Europe [2], whereas ‘‘potholes’’ is a synonym used in North America [3]. Kettle holes evolved from topographic depressions formed by delayed melting of remnant ice blocks during the ice retreat after the Pleistocene ~10,000–12,000 years ago [3][4]. Older glaciations created similar depressions, but most were lost as a result of bank erosion and sedimentation. Kettle holes typically range in size from 0.01 to 3 ha. Most undergo severe wet–dry cycles and some have ephemeral water bodies [5].

    Kettle holes fulfill important hydrological and ecological functions [6]. Their storage capacity influences a landscape’s water retention function and the moisture they provide through evapotranspiration affects local microclimate [7]. They serve as a refuge for endangered species and comprise habitats that promote biodiversity (e.g., [8][9]). Due to their small size and the usually high number of kettle holes in a region, they offer interesting opportunities for ecological research and modeling. In North America, kettle holes represent one of the largest and hydrologically most diverse populations of inland wetlands [10].

    Kettle holes are mostly situated in agricultural landscapes. They are often affected by agricultural management and in turn affect the fields surrounding them. The presence of kettle holes in a field may cause conflicts between nature conservation and farmers’ economic interests [5]. Intensive agricultural management may cause structural degradation in kettle holes, eutrophication, pollution by plant-protection products, or direct habitat destruction [11][12][13]. This may also impair the ecosystem functions and services supplied by kettle holes [14][15][16]. Furthermore, due to soil erosion, many kettle holes are increasingly filled with sediment originating from adjacent fields [17]. This threat is exacerbated by climate change which in many locations increases the probability of high intensity rainfall events and thereby the extent of soil erosion. The projected rise in global mean temperatures [18][19] until the end of the century is also likely to contribute to increased rates of evapotranspiration in many regions, resulting in an increasing rate of kettle holes permanently drying up. Both agricultural management and climate change may impair the ecosystem services supplied by kettle holes [14][15][16].

    2. Ecosystem Services Supplied by Kettle Holes

    In this part, we address the ecosystem services supplied by kettle holes in agricultural landscapes. 

    2.1. Hydrological Cycle and Flood Control (CICES Code 2.2.1.3)

    Service: The wet–dry cycle characteristic for kettle holes is central for their ability to regulate water flows. Their ability to store additional water provides a valuable flood protection service. The water budget of a kettle hole is determined by winter and early spring inputs. These are primarily driven by snowmelt and runoff over partially frozen soils, direct precipitation and seasonal lateral flows [7][20][21]. Kettle holes with very small catchment areas maintain their water level only by rainfall [22]. Water losses occur through evapotranspiration, spillover and lateral shallow groundwater recharge [20][23]. The water level of kettle holes responds to extremely wet or extremely dry weather conditions [24][25][26]. While evaporation rates can be relatively high, for some kettle holes evaporation alone cannot explain their complete drying-out. Lateral groundwater flow to the wet margins of the water body is a dominant cause of water loss for kettle holes [7][27][28].

    Linkages with agricultural management: Water level fluctuations in kettle holes depend on soil and crop management, as well as drainage practices, and mostly follow weather and vegetation cycles [7]. In North America, a significantly lower water table as well as a lower fluctuation of the water levels was detected in kettle holes within grassland landscapes compared to kettle holes within tilled agricultural landscapes [29][30]. Flooding of kettle holes may also lead to crop damages in bordering fields. However, in dry years, kettle holes can act as water suppliers for surrounding crops [31]. This is consistent with findings by Kanwar et al. [32] and Ahmad et al. [33] who found a negative effect on crop yields during wet years and a potential yield improvement during dry years.

    2.2. Chemical Condition of Freshwaters (CICES Code 2.2.5.1)

    Service: Individually, kettle holes may seem insignificant, but collectively they play an important role in improving water quality in agricultural catchments [34]. Natural vegetation around kettle holes acts as a buffer strip, filtering particles and chemical inputs from runoff, with a positive effect on water quality. Kettle holes are sometimes connected to groundwater. While their filtering effect may improve the water quality, they may also be polluted by contaminated groundwater streams [35] or speed up groundwater pollution if they themselves are polluted.

    Linkages with agricultural management: Given the intensification of agriculture, documented eutrophication of kettle holes is not surprising [36][37]. Water quality of kettle holes may be degraded as the result of waterborne or windborne sediment inputs [38], although maintenance of vegetation buffer strips may mitigate some impacts [39]. As some crops leave the soil more prone to erosion, e.g., tuber crops or crops planted in wider rows, and some crops are typically managed with higher amounts of pesticides and fertilizers than others, the choice of crop rotation affects water quality in kettle holes. Adapted management of agricultural fields around kettle holes is necessary to improve water quality. Regular monitoring of the water quality in kettle holes is desirable.

    2.3. Nursery Populations and Habitats (CICES Code 2.2.2.3)

    Service: This service also includes the protection of gene pools. Habitats for plants provided by kettle holes are often characterized by changing water levels. For instance, low water levels and occasional drying up (dry marsh phase) stimulate plant recruitment from diverse seed banks and increase productivity by mobilizing nutrients. In contrast, high water levels during deluges (lake marsh phase) cause turnover in plant populations, creating greater interspersion of emergent cover and open water, but lower overall productivity [40]. Like all temporary ponds, kettle holes are well known for their richness of annual plant species and often harbor numerous rare and endangered species [41][42]. For example, a study surveying 46 small kettle holes in Germany found 254 plant species, including 21 on the federal state’s red list [43][44]. Besides supporting high plant diversity, kettle holes constitute a source of food and water for wild animals such as deer, wild boars, bats and migratory birds [45][46][47][48]. They also provide refuge to many rodents [49]. Kettle holes may function as important stepping stone biotopes in agricultural landscapes. The loss of even small wetlands areas in the landscape may therefore have a strong detrimental effect on biodiversity [50]. While enabling genetic exchange and preventing habitat fragmentation generally contributes to preserving species and gene pools, it may, under very specific circumstances, also have negative implications by facilitating the spread of diseases or invasive species [51].

    Linkages with agricultural management: Negative effects of crop management on farmland biodiversity due to artificial drainage, tillage (e.g., increased turbidity and destruction of invertebrate eggs) [52] and high applications of pesticides and fertilizers are well documented [53][54]. Farmland intensification has led to a severe decline in the diversity of plant species [13] and amphibians [15] found around kettle holes. Balancing the interests of biodiversity conservation with agricultural production is important [55][56]. Therefore, Savoie et al. [57] suggest the harvest and energetic use of woody vegetation (shrubs and willows) around kettle holes as a solution. Biomass could be harvested on a 4–5-year cycle. Savoie et al. [57] state that beyond the generation of renewable energy, wood waste could contribute to moisture retention, soil nutrient cycling and the creation of habitat for wildlife, while biomass removal would contribute to reducing nutrient levels, thereby mitigating eutrophication.

    2.4. Pollination (CICES Code 2.2.2.1)

    Service: Research done by Vickruck et al. [58] demonstrates that small in-field wetland remnants, such as kettle holes, play an important role in supporting native pollinator communities in intensive agricultural landscapes. They are important nesting and foraging resources and support a highly diverse community of native bees [58]. Pollination services provided by wild bee species are crucial to the economy and food security of human populations, as well as playing a pivotal role in maintaining global biodiversity [59][60][61]. However, only one of the papers identified in our literature review addresses the value of kettle holes for pollinator communities. More research is desirable.

    Linkages with agricultural management: Pollinator declines have been linked to multiple factors, including pesticides [62], parasites [63], climate change [64][65] and habitat loss [66], of which habitat loss is considered the most pervasive [63][67][68]. Reducing the application of pesticides in the direct vicinity of kettle holes and maintaining herbaceous buffer strips is likely to improve the suitability of kettle holes as habitats for pollinators.

    2.5. Chemical Composition of Atmosphere and Oceans (CICES Code 2.2.6.1)

    There is disagreement considering the role of kettle holes for climate change mitigation. Withey and van Kooten [69] highlight their potential to store methane and carbon dioxide. Organic carbon sequestration per unit area of sediment has been suggested to be at least an order of magnitude higher in small lakes (including kettle holes) than in larger lakes [70][71][72]. However, while kettle holes are prone to organic matter burial [73][74], dry–wet cycles help to counter silting up [75] as buried material is mineralized again during dry phases [76]. Consequently, Philips and Beeri [77], Gleason et al. [78], Pennock et al. [79], Brinson and Eckles [80] and Tangen et al. [81] indicate that kettle holes are net producers of greenhouse gases (GHG). The net effect of GHG production and mitigation by kettle holes strongly depends on wet–dry cycles and will therefore vary between kettle holes of different hydrological regimes.

    Linkages with agricultural management: None of the reviewed articles addressed the influence of agriculture management on GHG production or mitigation by kettle holes. However, as management affects water levels and wet–dry cycles of kettles holes through land cover and potentially artificial drainage, it is likely to also affect their GHG balance.

    2.6. Biotic Remediation of Wastes (CICES Code 2.1.1.1)

    Service: This service is strongly correlated with the service Regulation of the chemical condition of freshwaters by living processes (CICES code 2.2.5.1). Kettle holes play an active role in nutrient cycling [82][83][84]. They use excess nutrients from fertilization of surrounding fields for biomass production. Other pollutants may be broken up by microorganisms living in the kettle holes. While nutrients and other pollutants may also be fixed within the sediment layer, this effect is of only minor importance where kettle holes fall dry for extended periods of time, strongly reducing the amount of sediment.

    Linkages with agricultural management: Kettle holes are sinks for nutrients and contaminants from agricultural fields. While they may help to remediate organic wastes, their ability to do so depends on a healthy ecosystem. Management on the fields surrounding kettle holes should seek to minimize erosion, as well as fertilizer and pesticide inputs.

    2.7. Local Regulation of Air Temperature and Humidity (CICES Code 2.2.6.2)

    Service: As small water bodies, kettle holes increase the humidity in their direct vicinity while the vegetation around them may lower wind speeds [7][85].

    Linkages with agricultural management: The colder and moister microclimate around kettle holes may help to mitigate drought effects in surrounding crop areas. However, it is also considered to be conducive to the growth of pathogenic fungi [86]. More research about the extent of services or disservices is desirable.

    2.8. Aesthetics from Interactions with Nature (CICES Code 3.1.2.4)

    Service: Kettle holes may increase the variability of otherwise monotonous agricultural landscapes and have a positive influence on landscape aesthetics. This service is only mentioned by Lipp [85], who considered it to contribute to the recreation potential of kettle holes.

    Linkages with agricultural management: Linkages with agricultural management were not discussed in Lipp [85]. However, aesthetic perception of wetland areas is linked to visual attributes, such as transparency and color of water, as well as presence and appearance of aquatic vegetation [87]. Clear waters are generally preferred [88][89]. High nutrient inputs due to fertilizer application in surrounding fields may therefore lower the supply of this service while buffer strips with visually appealing vegetation may increase it.

    3. Conclusions and Recommendations

    Water regime, water quality and habitat function of kettle holes can be highly impaired by intensive agricultural management in fields surrounding kettle holes if these practices cause erosion or include high levels of fertilizer and pesticide application. A loss of kettle holes and of the ecosystem services they supply could impact the regulation of water flows in agricultural landscapes and lead to a loss of habitats and biodiversity, including those of endangered amphibian species.

    Kettle holes need to be addressed more precisely in policy documents and conservation programs. Policies are required to encourage farmers to better adapt their management in the areas surrounding kettle holes in order to improve kettle hole protection. As farmers can profit only in a very limited way from the ecosystem services supplied by kettle holes, subsidies may provide an important means for balancing economic and environmental considerations.

    Providing society and policy makers with information about the ecosystem services supplied by kettle holes and about the threats to this supply contributes to informed decision making and sustainable management. This will also require more field data. More effective monitoring of kettle holes will be of critical importance with regard to understanding and predicting responses of kettle holes to different types of agricultural management, to raise awareness for kettle hole threats, enable enforcement of policies and ensure compliance with conservation requirements.

    This entry is adapted from 10.3390/agronomy10091326

    References

    1. Burkhard, B.; Maes, J.. Mapping Ecosystem Services; Burkhard, B., Maes, J., Eds.; Sofia: Bulgaria, 2017; pp. -.
    2. Watznauer, A.. Wörterbuch der Geowissenschaften Deutsch-Englisch; Thun and Frankfurt/Main: Germany, 1989; pp. 387.
    3. Kalettka, T.; Rudat, C.; Quast, J. 18 “Potholes” in Northeast German agro-landscapes: Functions, land use impacts, and protection strategies. In Ecosystem Approaches to Landscape Management in Central Europe; Tenhunen, J.D., Lenz, R., Hentschel, R., Eds.; (Ecological studies); Springer: Berlin, Germany, 2001; Volume 147, pp. 291–298.
    4. Merbach, W.; Kalettka, T.; Rudat, C.; Augustin, J. Trace gas emissions from riparian areas of small eutrophic inland waters in Northeast-Germany. In Wetlands in Central Europe; Springer Science and Business Media LLC: Berlin, Germany, 2002; pp. 235–244.
    5. Thomas Kalettka; Catrin Rudat; Hydrogeomorphic types of glacially created kettle holes in North-East Germany. Limnologica 2006, 36, 54-64, 10.1016/j.limno.2005.11.001.
    6. M. Hayashi; Garth Van Der Kamp; Randy Schmidt; Focused infiltration of snowmelt water in partially frozen soil under small depressions. Journal of Hydrology 2003, 270, 214-229, 10.1016/s0022-1694(02)00287-1.
    7. Horst H. Gerke; Sylvia Koszinski; Thomas Kalettka; Michael Sommer; Structures and hydrologic function of soil landscapes with kettle holes using an integrated hydropedological approach. Journal of Hydrology 2010, 393, 123-132, 10.1016/j.jhydrol.2009.12.047.
    8. Rittenhouse, T.A.G.; Semlitsch, R.D. Distribution of amphibians in terrestrial habitat surrounding wetlands. Wetlands 2007, 27, 153–161.
    9. Kłosowski, S.; Jabłońska, E. Aquatic and swamp plant communities as indicators of habitat properties of astatic water bodies in north-eastern Poland. Limnologica 2009, 39, 115–127.
    10. Robert A. Gleason; N. H. Euliss; B. A. Tangen; M. K. Laubhan; B. A. Browne; USDA conservation program and practice effects on wetland ecosystem services in the Prairie Pothole Region. Ecological Applications 2011, 21, S65-S81, 10.1890/09-0216.1.
    11. Kalettka, T.; Rudat, C.; Quast, J.. Ecosystem Approaches to Landscape Management in Central Europe; Tenhunen, J.D., Lenz, R., Hentschel, R., Eds.; Springer: Berlin, Germany, 2001; pp. 291–298.
    12. Céréghino, R.; Biggs, J.; Oertli, B.; Declerck, S.A.J. The ecology of European ponds: Defining the characteristics of a neglected freshwater habitat. In Pond Conservation in Europe; Springer Science and Business Media LLC: Berlin, Germany, 2007; pp. 1–6.
    13. Altenfelder, S.; Raabe, U.; Albrecht, H. Effects of water regime and agricultural land use on diversity and species composition of vascular plants inhabiting temporary ponds in northeastern Germany. Tuexenia 2014, 34, 145–162.
    14. Merbach, W.; Kalettka, T.; Rudat, C.; Augustin, J.. Wetlands in Central Europe; Springer Science and Business Media LLC: Berlin, Germany, 2002; pp. 235–244.
    15. Berger, G.; Pfeffer, H.; Kalettka, T. Amphibienschutz in kleingewässerreichen Ackerbaugebieten: Grundlagen Konflikte Lösungen (Conservation of amphibians in agricultural landscapes rich in small water bodies); Natur & Text: Rangsdorf, Germany, 2011.
    16. Lischeid, G.; Kalettka, T. Grasping the heterogeneity of kettle hole water quality in Northeast Germany. Hydrobiologia 2011, 689, 63–77.
    17. Marlene Pätzig; Thomas Kalettka; Michael Glemnitz; Gert Berger; What governs macrophyte species richness in kettle hole types? A case study from Northeast Germany. Limnologica 2012, 42, 340-354, 10.1016/j.limno.2012.07.004.
    18. Solomon, S.; Qin, D.; Manning, M.; Chen, Z.; Marquis, M.; Averyt, K.B.; Tignor, M.; Miller, H.L. (Eds.) Climate Change 2007—The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change; Cambridge University Press: Cambridge, UK; New York, NY, USA, 2007.
    19. Pachauri, R.K.; Meyer, L.A.; Vicente, R.B.; John, B.; Wolfgang, L.A.; Renate, C.; John, A.C.; Leon, C.; Qin, D.; Purnamita, D.; et al. Climate Change 2014—Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Pachauri, R.K., Meyer, L.A., Eds.; IPCC: Geneva, Switzerland, 2014; p. 151.
    20. Van Der Kamp, G.; Hayashi, M. Groundwater-wetland ecosystem interaction in the semiarid glaciated plains of North America. Hydrogeol. J. 2008, 17, 203–214.
    21. Shaw, D.A.; Pietroniro, A.; Martz, L. Topographic analysis for the prairie pothole region of Western Canada. Hydrol. Process. 2012, 27, 3105–3114.
    22. Michał Gąsiorowski; Deposition Rate of Lake Sediments Under Different Alternative Stable States. Geochronometria 2008, 32, 29-35, 10.2478/v10003-008-0020-y.
    23. Susann Berthold; Laurence R. Bentley; M. Hayashi; Integrated hydrogeological and geophysical study of depression-focused groundwater recharge in the Canadian prairies. Water Resources Research 2004, 40, -, 10.1029/2003wr002982.
    24. Moorhead, K.K. Effects of drought on the water-table dynamics of a southern Appalachian mountain floodplain and associated fen. Wetlands 2003, 23, 792–799.
    25. Johnson, W.C.; Boettcher, S.E.; Poiani, K.A.; Guntenspergen, G. Influence of weather extremes on the water levels of glaciated prairie wetlands. Wetlands 2004, 24, 385–398.
    26. Dempster, A.; Ellis, P.; Wright, B.; Stone, M.; Price, J. Hydrogeological evaluation of a southern Ontario kettle-hole peatland and its linkage to a regional aquifer. Wetlands 2006, 26, 49–56.
    27. J.M. Ferone; K.J. DeVito; Shallow groundwater–surface water interactions in pond–peatland complexes along a Boreal Plains topographic gradient. Journal of Hydrology 2004, 292, 75-95, 10.1016/j.jhydrol.2003.12.032.
    28. M. Hayashi; Garth Van Der Kamp; Dave L. Rudolph; Water and solute transfer between a prairie wetland and adjacent uplands, 2. Chloride cycle. Journal of Hydrology 1998, 207, 56-67, 10.1016/s0022-1694(98)00099-7.
    29. Euliss, N.H.; Mushet, D.M. Water-level fluctuation in wetlands as a function of landscape condition in the prairie pothole region. Wetlands 1996, 16, 587–593.
    30. Van Der Kamp, G.; Stolte, W.J.; Clark, R.G. Drying out of small prairie wetlands after conversion of their catchments from cultivation to permanent brome grass. Hydrol. Sci. J. 1999, 44, 387–397.
    31. Larissa Raatz; Nina Bacchi; Karin Pirhofer-Walzl; Michael Glemnitz; Marina E. H. Müller; Jasmin Joshi; Christoph Scherber; How much do we really lose?-Yield losses in the proximity of natural landscape elements in agricultural landscapes.. Ecology and Evolution 2019, 9, 7838-7848, 10.1002/ece3.5370.
    32. R. S. Kanwar; J. L. Baker; Saqib Mukhtar; Excessive Soil Water Effects at Various Stages of Development on the Growth and Yield of Corn. Transactions of the ASAE 1988, 31, 0133-0141, 10.13031/2013.30678.
    33. N. Ahmad; R. S. Kanwar; T. C. Kaspar; T. B. Bailey; Effect of Soil Surface Submergence and a Water Table on Vegetative Growth and Nutrient Uptake of Corn. Transactions of the ASAE 1992, 35, 1173-1177, 10.13031/2013.28716.
    34. McKergow, L.; Gallant, J.; Dowling, T.. Proceedings of MODSIM 2007 International Congress on Modelling and Simulation; University of Canterbury: Christchurch: New Zealand, 2007; pp. 74-80.
    35. Gunnar Lischeid; Thomas Kalettka; Matthias Holländer; Jörg Steidl; Christoph Merz; Ralf Dannowski; Tobias L. Hohenbrink; Christian Lehr; Gabriela Onandia; Florian Reverey; et al. Natural ponds in an agricultural landscape: External drivers, internal processes, and the role of the terrestrial-aquatic interface. Limnologica 2018, 68, 5-16, 10.1016/j.limno.2017.01.003.
    36. Engstrom, D.R.; Schottler, S.P.; Leavitt, P.R.; Havens, K.E. A reevaluation of the cultural eutrophication of Lake Okeechobee using multiproxy sediment records. Ecol. Appl. 2006, 16, 1194–1206.
    37. Preston, T.M.; Sojda, R.S.; Gleason, R.A. Sediment accretion rates and sediment composition in Prairie Pothole wetlands under varying land use practices, Montana, United States. J. Soil Water Conserv. 2013, 68, 199–211.
    38. Charles D. Dieter; Water Turbidity in Tilled and Untilled Prairie Wetlands. Journal of Freshwater Ecology 1991, 6, 185-189, 10.1080/02705060.1991.9665292.
    39. Naomi E. Detenbeck; Colleen M. Elonen; Debra L. Taylor; Anne M. Cotter; Frank A. Puglisi; William D. Sanville; Effects of agricultural activities and best management practices on water quality of seasonal prairie pothole wetlands. Wetlands Ecology and Management 2002, 10, 335-354, 10.1023/a:1020397103165.
    40. W. Carter Johnson; Bruce Millett; Tagir Gilmanov; Richard A. Voldseth; Glenn R. Guntenspergen; David E. Naugle; Vulnerability of Northern Prairie Wetlands to Climate Change. BioScience 2005, 55, 863, 10.1641/0006-3568(2005)055[0863:vonpwt]2.0.co;2.
    41. Dreger, F. Sölle—Bedeutung für die Biodiversität in Agrarlandschaften unterschiedlicher Landschaftsräume. Beiträge Forstwirtschaft Landschaftsökol. 2002, 36, 88–92.
    42. Davies, B.R.; Biggs, J.; Williams, P.; Whitfield, M.; Nicolet, P.; Sear, D.; Bray, S.; Maund, S. Comparative biodiversity of aquatic habitats in the European agricultural landscape. Agric. Ecosyst. Environ. 2008, 125, 1–8.
    43. Ristow, M.; Herrmann, A.; Illig, H.; Klemm, G.; Kummer, V.; Kläge, H.-C.; Machatzi, B.; Raetzel, S.; Schwarz, R.; Zimmermann, F. Liste und Rote Liste der etablierten Gefäßpflanzen Brandenburgs. Naturschutz Landschaftspflege Brandenburg 2006, 15, 70–80.
    44. Lozada-Gobilard, S.; Stang, S.; Pirhofer-Walzl, K.; Kalettka, T.; Heinken, T.; Schröder, B.; Eccard, J.; Joshi, J. Environmental filtering predicts plant-community trait distribution and diversity: Kettle holes as models of meta-community systems. Ecol. Evol. 2019, 9, 1898–1910.
    45. Dovrat, G.; Perevolotsky, A.; Ne’Eman, G. Wild boars as seed dispersal agents of exotic plants from agricultural lands to conservation areas. J. Arid Environ. 2012, 78, 49–54.
    46. Soons, M.B.; Brochet, A.; Kleyheeg, E.; Green, A.J. Seed dispersal by dabbling ducks: An overlooked dispersal pathway for a broad spectrum of plant species. J. Ecol. 2016, 104, 443–455.
    47. Flaherty, K.L.; Rentch, J.S.; Grafton, W.N.; Anderson, J.T. Timing of white-tailed deer browsing affects wetland plant communities. Plant Ecol. 2018, 219, 313–324.
    48. Roeleke, M.; Johannsen, L.; Voigt, C.C. How Bats Escape the Competitive Exclusion Principle—Seasonal Shift from Intraspecific to Interspecific Competition Drives Space Use in a Bat Ensemble. Front. Ecol. Evol. 2018, 6, 101.
    49. Christina Fischer; Boris Schröder; Predicting spatial and temporal habitat use of rodents in a highly intensive agricultural area. Agriculture, Ecosystems & Environment 2014, 189, 145-153, 10.1016/j.agee.2014.03.039.
    50. Carol A. Johnston; N. E. McIntyre; Effects of cropland encroachment on prairie pothole wetlands: numbers, density, size, shape, and structural connectivity. Landscape Ecology 2019, 34, 827-841, 10.1007/s10980-019-00806-x.
    51. Shyam M Thomas; Kirk A. Moloney; Combining the effects of surrounding land-use and propagule pressure to predict the distribution of an invasive plant. Biological Invasions 2014, 17, 477-495, 10.1007/s10530-014-0745-7.
    52. Swanson, G.A.; Duebbert, H.F.. Northern Prairie Wetlands; van der Valk, A.G., Eds.; Iowa State University Press: Ames, IA, USA, 1989; pp. 228–267.
    53. Stoate, C.; Boatman, N.D.; Borralho, R.J.; Carvalho, C.; De Snoo, G.R.; Eden, P. Ecological impacts of arable intensification in Europe. J. Environ. Manag. 2001, 63, 337–365.
    54. Geiger, F.; De Snoo, G.R.; Berendse, F.; Guerrero, I.; Morales, M.B.; Oñate, J.J.; Eggers, S.; Pärt, T.; Bommarco, R.; Bengtsson, J.; et al. Landscape composition influences farm management effects on farmland birds in winter: A pan-European approach. Agric. Ecosyst. Environ. 2010, 139, 571–577.
    55. Barraquand, F.; Martinet, V. Biological conservation in dynamic agricultural landscapes: Effectiveness of public policies and trade-offs with agricultural production. Ecol. Econ. 2011, 70, 910–920.
    56. 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. Biol. Conserv. 2012, 151, 53–59.
    57. Savoie, P.; Lavoie, F.; D’Amours, L.; Schroeder, W.; Kort, J. Harvesting natural willow rings with a bio-baler around Saskatchewan prairie marshes. Can. Biosyst. Eng. 2010, 52, 2.1–2.5.
    58. Jess L. Vickruck; Lincoln R. Best; Michael P. Gavin; James H. Devries; Paul Galpern; Pothole wetlands provide reservoir habitat for native bees in prairie croplands. Biological Conservation 2019, 232, 43-50, 10.1016/j.biocon.2019.01.015.
    59. Gallai, N.; Salles, J.-M.; Settele, J.; Vaissière, B.E. Economic valuation of the vulnerability of world agriculture confronted with pollinator decline. Ecol. Econ. 2009, 68, 810–821.
    60. Eilers, E.J.; Kremen, C.; Greenleaf, S.S.; Garber, A.K.; Klein, A. Contribution of Pollinator-Mediated Crops to Nutrients in the Human Food Supply. PLoS ONE 2011, 6, e21363.
    61. Vanbergen, A.J.; Initiative, T.I.P. Threats to an ecosystem service: Pressures on pollinators. Front. Ecol. Environ. 2013, 11, 251–259.
    62. Dara Anne Stanley; Michael P.D. Garratt; Jennifer B. Wickens; Victoria J. Wickens; Simon G. Potts; Nigel E. Raine; Neonicotinoid pesticide exposure impairs crop pollination services provided by bumblebees. Nature 2015, 528, 548-550, 10.1038/nature16167.
    63. Dave Goulson; Elizabeth Nicholls; Ellen Rotheray; Cristina Botías; Qualifying pollinator decline evidence--Response. Science 2015, 348, 982-982, 10.1126/science.348.6238.982.
    64. Giannini, T.C.; Acosta, A.L.; Garófalo, C.A.; Saraiva, A.M.; Alves-Dos-Santos, I.; Imperatriz-Fonseca, V.L. Pollination services at risk: Bee habitats will decrease owing to climate change in Brazil. Ecol. Model. 2012, 244, 127–131.
    65. Kerr, J.T.; Pindar, A.; Galpern, P.; Packer, L.; Potts, S.G.; Roberts, S.M.; Rasmont, P.; Schweiger, O.; Colla, S.R.; Richardson, L.L.; et al. Climate change impacts on bumblebees converge across continents. Science 2015, 349, 177–180.
    66. Brian J. Spiesman; Brian D. Inouye; Habitat loss alters the architecture of plant–pollinator interaction networks. Ecology 2013, 94, 2688-2696, 10.1890/13-0977.1.
    67. Fahrig, L. Effects of Habitat Fragmentation on Biodiversity. Annu. Rev. Ecol. Evol. Syst. 2003, 34, 487–515.
    68. Koh, I.; Lonsdorf, E.V.; Williams, N.M.; Brittain, C.; Isaacs, R.; Gibbs, J.; Ricketts, T.H. Modeling the status, trends, and impacts of wild bee abundance in the United States. Proc. Natl. Acad. Sci. USA 2015, 113, 140–145.
    69. Withey, P.; van Kooten, G.C. Wetlands retention and optimal management of waterfowl habitat under climate change. J. Agric. Resour. Econ. 2014, 39, 1–18.
    70. Dean, W.E.; Gorham, E. Magnitude and significance of carbon burial in lakes, reservoirs, and peatlands. Geology 1998, 26, 535–538.
    71. Downing, J.A.; Cole, J.J.; Middelburg, J.J.; Striegl, R.G.; Duarte, C.M.; Kortelainen, P.; Prairie, Y.T.; Laube, K.A. Sediment organic carbon burial in agriculturally eutrophic impoundments over the last century. Glob. Biogeochem. Cycles 2008, 22.
    72. Heathcote, A.J.; Filstrup, C.; Kendall, D.; Downing, J. Biomass pyramids in lake plankton: Influence of Cyanobacteria size and abundance. Inland Waters 2016, 6, 250–257.
    73. Kleeberg, A.; Neyen, M.; Schkade, U.-K.; Kalettka, T.; Lischeid, G. Sediment cores from kettle holes in NE Germany reveal recent impacts of agriculture. Environ. Sci. Pollut. Res. 2015, 23, 7409–7424.
    74. Kazanjian, G.; Flury, S.; Attermeyer, K.; Kalettka, T.; Kleeberg, A.; Premke, K.; Köhler, J.; Hilt, S. Primary production in nutrient-rich kettle holes and consequences for nutrient and carbon cycling. Hydrobiologia 2017, 806, 77–93.
    75. Florian Reverey; Hans-Peter Grossart; Katrin Premke; Gunnar Lischeid; Carbon and nutrient cycling in kettle hole sediments depending on hydrological dynamics: a review. Hydrobiologia 2016, 775, 1-20, 10.1007/s10750-016-2715-9.
    76. María Sahuquillo; Maria Rosa Miracle; Sara María Morata; Eduardo Vicente; Nutrient dynamics in water and sediment of Mediterranean ponds across a wide hydroperiod gradient. Limnologica 2012, 42, 282-290, 10.1016/j.limno.2012.08.007.
    77. Rebecca L. Phillips; Ofer Beeri; The role of hydropedologic vegetation zones in greenhouse gas emissions for agricultural wetland landscapes. CATENA 2008, 72, 386-394, 10.1016/j.catena.2007.07.007.
    78. Robert A. Gleason; Brian A. Tangen; Bryant A. Browne; Ned H. Euliss Jr.; Greenhouse gas flux from cropland and restored wetlands in the Prairie Pothole Region. Soil Biology and Biochemistry 2009, 41, 2501-2507, 10.1016/j.soilbio.2009.09.008.
    79. Dan Pennock; Thomas Yates; Angela Bedard-Haughn; Kim Phipps; R E Farrell; Rhonda McDougal; Landscape controls on N2O and CH4 emissions from freshwater mineral soil wetlands of the Canadian Prairie Pothole region. Geoderma 2010, 155, 308-319, 10.1016/j.geoderma.2009.12.015.
    80. Mark M. Brinson; S. Diane Eckles; U.S. Department of Agriculture conservation program and practice effects on wetland ecosystem services: a synthesis. Ecological Applications 2011, 21, S116-S127, 10.1890/09-0627.1.
    81. Brian A. Tangen; Ray Finocchiaro; Robert A. Gleason; Effects of land use on greenhouse gas fluxes and soil properties of wetland catchments in the Prairie Pothole Region of North America. Science of The Total Environment 2015, 533, 391-409, 10.1016/j.scitotenv.2015.06.148.
    82. Cole, J.J.; Prairie, Y.T.; Caraco, N.F.; McDowell, W.H.; Tranvik, L.J.; Striegl, R.G.; Duarte, C.M.; Kortelainen, P.; Downing, J.A.; Middelburg, J.J.; et al. Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget. Ecosystems 2007, 10, 172–185.
    83. Battin, T.J.; Luyssaert, S.; Kaplan, L.A.; Aufdenkampe, A.K.; Richter, A.; Tranvik, L.J. The boundless carbon cycle. Nat. Geosci. 2009, 2, 598–600.
    84. Raymond, P.A.; Hartmann, J.; Lauerwald, R.; Sobek, S.; McDonald, C.P.; Hoover, M.; Butman, D.; Striegl, R.; Mayorga, E.; Humborg, C.; et al. Global carbon dioxide emissions from inland waters. Nature 2013, 503, 355–359.
    85. Lipp, T. Kettle Holes and Landscape Planning Consideration of a typical landscape element in the Federal States of Brandenburg and Mecklenburg-Vorpommern. Naturschutz Landschaftsplanung 2006, 38, 287.
    86. M Müller; Sylvia Koszinski; Donovan E. Bangs; Marc Wehrhan; Andreas Ulrich; Gernot Verch; Alexander Brenning; Crop biomass and humidity related factors reflect the spatial distribution of phytopathogenic Fusarium fungi and their mycotoxins in heterogeneous fields and landscapes. Precision Agriculture 2016, 17, 698-720, 10.1007/s11119-016-9444-y.
    87. Marylise Cottet; Hervé Piegay; Gudrun Bornette; Does human perception of wetland aesthetics and healthiness relate to ecological functioning?. Journal of Environmental Management 2013, 128, 1012-1022, 10.1016/j.jenvman.2013.06.056.
    88. Gregory, K.; Davis, R. The Perception of Riverscape Aesthetics: An Example from Two Hampshire Rivers. J. Environ. Manag. 1993, 39, 171–185.
    89. House, M.A.; Sangster, E.K. Public Perception of River-Corridor Management. Water Environ. J. 1991, 5, 312–316.
    More