US farmers' adaptations to climate change: a systematic review of adaptation-focused studies in the US agriculture context

Agriculture in the US is vulnerable to climate change impacts. Evidence suggests that because of climate change impacts (e.g. increased temperature, weather variability, extreme rainfall events), the US agriculture is experiencing damage in crop yields (Lobell et al 2011). Studies found that a higher temperature is associated with decreased wheat yield (Tack et al 2015), corn yield (Hatfield et al 2018), and yield variability of maize, soybeans, and sorghum (Schauberger et al 2017, Kukal and Irmak 2018). Similar to temperature, Lesk et al (2020) claimed that extreme rainfall of greater than 50 mm h⁻¹ could cause a reduction of maize and soybean yield in the US (see also Rosenzweig et al 2002). Over the next few decades, regardless of future emissions, the average temperature in the US will rise by at least 1.4 °C (2.5 °F), and the frequency and intensity of heavy rainfall will increase (Easterling et al 2017, Vose et al 2017). As a result, by the end of this century, US agriculture will experience more droughts, increased growing season temperature (Wehner et al 2017), and accelerated rate of soil erosion due to increased extreme rainfall events (O'Neal et al 2005, Gowda et al 2018). The outcomes of these perilous scenarios will be severe damages to crop yields–yield reduction can be more than 30% for some crops by 2100 (Schlenker and Roberts 2009, Rosenzweig et al 2014). Because the US is one of the top producers of food crops in the world (FAO 2020), the negative impacts of climate change on food crop production will affect national and global food security. Thus, it is vital to ensure that US farmers are adopting strategies to tackle climate change impacts.

The farmers in the US are adopting a range of strategies to deal with climate change impacts. For example, in the Northeastern part of the US, farmers adopted conservation agriculture practices along with frost protection measures to tackle weather anomalies—an example of climate change impacts (Jemison et al 2014, Lane et al 2018). On the other hand, in the Southeastern part, farmers relied on technological adaptation measures to irrigate their lands and deal with increasing droughts (van Dijl et al 2015). These adaptation measures helped the farmers sustain or enhance crop yield to some extent, as evidenced by Ray et al (2012). They found that crop yield increased in some parts of the US while stagnating in some parts. However, in a later work, they argued that current adaptation practices may not be enough to meet the demand in 2050 under changing climate (Ray et al 2013). Furthermore, Burke and Emerick (2016) found that current adaptations are insufficient to mitigate future climate change impacts.

Studies on climate adaptation in US agriculture focus on a variety of topics ranging from farmers' on-farm adaptations to scenario-based simulations to working with farmers to explore adaptations. For instance, Schattman et al (2016) identified several climate change risks associated with on-farm adaptation strategies in Vermont, while many studies focused on adaptation in different climate scenarios (e.g. Chhetri et al 2010) or irrigation regimes (e.g. Frisvold and Bai 2016). These studies are important to understand how farmers are adapting to climate change impacts, which adaptation strategies provide better outcomes, and what challenges need to be addressed for effective adaptations. Nevertheless, we have limited knowledge of which research areas of adaptation received more attention and which areas require more. Up until now, the review and synthesis articles on adaptation to climate change impacts in US agriculture concentrated on a particular adaptation strategy (i.e. cover crops) (Kaye and Quemada 2017), adaptation potential (Easterling 1996), capacity assessments (Parson et al 2003), or a specific region (Elias et al 2019). A review article on the overall adaptation literature in the context of US agriculture can provide knowledge about existing research trends and identify the areas that need to be prioritized. Furthermore, a review article can elucidate how farmers are adapting to climate change impacts across the US, what adaptation actions have been found useful, and what challenges the farmers may encounter. This article aims to address these issues by systematically reviewing the peer-reviewed literature on adaptation to climate change in US agriculture. In the next section, the methods of selecting peer-reviewed articles are discussed. The results are presented later, followed by a discussion and conclusion.

A systematic literature review (SLR) of the peer-reviewed articles published on climate adaptations in US agriculture has been conducted using the ROSES (Reporting Standards for Systematic Evidence Synthesis in Environmental Research) protocol. The ROSES protocol for SLR is specially designed for conservation and environmental management to synthesize different types of environmental evidence (Haddaway et al 2018) and it ensures the replication of research. The articles were searched in the Web of Science platform using different combinations of search keywords that are relevant to adaptation to climate change impacts (see supplementary table 1). Each of the search queries provided a set of articles. Only the articles that were published between 1980 and 2022 were considered in this study. Duplicate articles were removed and only peer-reviewed English-language articles were included. The focus of this research is on food crops, and thus, only those articles that focused on food crops, such as cereals, legumes, vegetables, fruits, were included and livestock or dairy agriculture-related articles were excluded. In order to ensure maximum inclusivity, articles were extracted from the Google Scholar platform using similar search keywords (see supplementary table 1). This study only considered primary research articles and review articles were removed. The search queries and omission of duplicated titles generated a total of 1281 articles for review (figure 1).

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The SLR process involves a systematic way of including and excluding articles for final review (Haddaway and Pullin 2014). Hence, a set of inclusion and exclusion criteria were developed based on which relevant articles for the final review were selected (see table 1). These criteria had been established to ensure the selection of adaptation-related peer-reviewed articles and distinguish between farmers' climate change beliefs versus perceptions and farmers' adaptations, climate change impacts versus adaptation to climate change impacts, and US-focused studies versus outside-US studies. Based on these criteria, a total of 123 articles were selected for full-text review through title and abstract screening. Later, a full-text review of these articles generated 95 articles relevant to this study's objectives. Lastly, a critical appraisal was done to filter out articles that were methodologically weak. This final step did not yield the removal of any article for final review. In order to avoid biases, these processes were repeated three times. See table 1 for details.

It is important to note that there are articles that analyzed climate change impacts (current and future) on agricultural yields but did not focus on adaptation but rather suggested some recommendations or concluding remarks. This study did not consider those articles as they did not examine adaptations. Furthermore, there are articles that focus on conservation agricultural practices (e.g. cover crops, reduced tillage), many of which can be considered adaptation strategies. However, if those articles did not discuss adaptation or frame their argument around it, they were not considered adaptation articles. For instance, Seifert et al (2018) analyzed the performance of cover crops but did not discuss adaptation; thus, it was not considered in this review.

The SLR reveals that most articles focused on farmers' adaptations to climate change were published after 2010. Only 6% of the articles were published before 2010, whereas 66% were published after 2015. About 20% of the articles were published in the last two years, indicating a surging trend of research focusing on US farmers' adaptations. Although no particular reason can be attributed with certainty to this surge, one of the key reasons could be the ramping up of climate finance commitment by developed countries in 2009 which might lead to a greater interests in climate adaptation by US researchers. Figure 2 presents the number of articles published over time. This study further analyzed which states and regions received more attention by adaptation studies and found that the Northwest part of the US, comprising Washington, Oregon, and Idaho, received the greatest attention, followed by the Midwest and Southeast. Some of the states in the Northeast part and Southwest parts received more attention, such as New York, Vermont, and California. In the Northern Plains, the eastern states were of focus as the western part is mountainous. Notably, despite having large areas under food crop production, Texas and Oklahoma received little attention. Figure 3 depicts the distribution of adaptation studies.

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The SLR of the articles related to adaptation to climate change further reveals a range of topics on climate adaptation in US agriculture. These articles are categorized into five themes based on their broad topical relevance: (i) reporting on-farm adaptations, (ii) exploring potential adaptations, (iii) evaluating specific adaptations, (iv) challenges of adaptations, and (v) perceptions toward adaptations (figure 3). The first theme includes articles that documented farmers' on-farm strategies to adapt to climate change impacts. The key objectives of the articles under the second theme were exploring potential strategies for farmers so that they can adapt to climate change-related hazards in a better way. These articles did not document what actions farmers are undertaking but rather identified what strategies could be beneficial for them using modeling approaches or opinion-based data. These articles did not seek to evaluate specific adaptation options; instead, their primary objectives were to identify the adaptation actions. The third theme includes the articles in which the main objectives were evaluating specific adaptation options. Instead of identifying adaptation options for farmers, these studies selected one or more adaptation actions and evaluated their effectiveness. The articles under the fourth theme focused on the challenges associated with undertaking adaptation actions, and the fifth theme of articles dealt with farmers' perceptions towards adaptation actions. It is important to note that a few articles can overlap in two themes. For example, articles under the first theme can discuss the adaptation challenges and thus overlap with the fourth theme. In those instances, the categorization took place based on the primary objective of those articles. Only three articles (i.e. Antle et al 2004, Burke and Emerick 2016, Ortiz-Bobea et al 2018) did not fall under any specific theme as they focused on estimating the impacts of general adaptations and assumed the challenges of adaptations. In the following subsections, I will elaborate on the findings under each of these themes.

3.1. Theme 1: reporting on-farm adaptations

Among the articles published on farmers' adaptations in the US, only around 17% of articles (16 out of 95) presented what adaptation strategies farmers undertake in their agricultural lands (figure 4). A majority of these studies (38%) concentrated on the Northeast part of the US (e.g. Jemison et al 2014, Schattman et al 2016, 2021, Warner et al 2017, Lane et al 2018) and 31% focused on the Midwest part (e.g. Mase et al 2017, Linder and Campbell-Arvai 2021, Skevas et al 2022), while only a few studies focused on the Southeast part (e.g. van Dijl et al 2015), Southwest part (e.g. Vásquez-León et al 2003, Nicholas and Durham 2012), and Northwest part of the US (e.g. Roesch-McNally et al 2020). These articles primarily focused on collecting empirical data through interviews with farmers or focus group discussions.

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From these studies, it is evident that US farmers are undertaking a range of adaptation strategies. These adaptation strategies can be categorized into five broad themes: water management, crop management, nutrient management, technological management, and financial management. Studies under this theme mostly focused on corn, soybeans, fruits, and vegetable growing regions, but they did not distinguish crop-wise adaptation strategies, instead reported the adaptation strategies for multiple crops combined or for a single crop. Furthermore, to answer 'adaptation to what?', these studies primarily considered climate change as a whole; only a few studies focused on specific hazards, such as drought (van Dijl et al 2015) and flooding (Warner et al 2017). The regional comparison indicates that more adaptations are reported in the Northeast region of the US compared to other parts; however, this does not essentially mean that farmers in the Northeast US are adapting more than others. Table 2 summarizes the adaptation strategies taken by the US farmers.

Table 2. US farmers' on-farm adaptation strategies.

Theme	Adaptation action	Crop	Region	Reference
Water management	Irrigation (e.g. traditional, micro irrigation, targeted irrigation, irrigation scheduling, drip irrigation)	Corn, soybeans, vegetables, fruits	Northeast, Southeast, Midwest, Northwest, Southwest, Southern Plains	Vásquez-León et al (2003), Knutson et al (2011), Nicholas and Durham (2012), Jemison et al (2014), van Dijl et al (2015), Doll et al (2017), Sweet et al (2017), Lane et al (2018), Roesch-McNally et al (2020), Linder and Campbell-Arvai (2021), Schattman et al (2021)
	Irrigation infrastructures (e.g. tile drainage, bank stabilization)	Corn, soybeans, vegetables, fruits	Northeast, Midwest	Jemison et al (2014), Doll et al (2017), Warner et al (2017), Sweet et al (2017), Lane et al (2018), Schattman et al (2021), Skevas et al (2022)
Crop management	Changing crop varieties	Corn, soybeans, vegetables, fruits	Northeast, Midwest, Northwest	Knutson et al (2011), Jemison et al (2014), Lane et al (2018), Roesch-McNally et al (2020), Skevas et al (2022)
	Crop diversification	Corn, soybeans, vegetables, fruits	Northeast, Midwest, Northwest	Jemison et al (2014), Schattman et al (2016), Mase et al (2017), Lane et al (2018), Roesch-McNally et al (2020), Linder and Campbell-Arvai (2021), Schattman et al (2021)
	Raised bed	Vegetables, fruits	Northeast, Northwest	Jemison et al (2014), Roesch-McNally et al (2020)
	Cover crop	Corn, soybeans, vegetables, fruits	Northeast, Midwest, Northwest	Lane et al (2018), Roesch-McNally et al (2020), Schattman et al (2021)
	Reduced or zero tillage	Corn, soybeans, vegetables, fruits	Midwest, Northeast	Knutson et al (2011), Lane et al (2018), Schattman et al (2021)
	Crop switching	Corn, soybeans	Entire US	Cui (2020)
	Crop rotation	Vegetables	Midwest, Northeast	Knutson et al (2011), Schattman et al (2021)
	Shifting planting dates	Corn, soybeans, vegetables, fruits	Northeast, Southeast	Lane et al (2018), Roesch-McNally et al (2020)
Nutrient management	Managing fertilizer or pesticide	Vegetables, fruits	Northeast, Southwest	Nicholas and Durham (2012), Linder and Campbell-Arvai (2021), Schattman et al (2021)
	Soil condition improvement (e.g. organic matter, permanent mulch, compost)	Vegetables	Northeast, Southeast, Midwest, Northwest	Knutson et al (2011), Jemison et al (2014), van Dijl et al (2015), Roesch-McNally et al (2020), Linder and Campbell-Arvai (2021), Schattman et al (2021)
Technological management	Adoption of new technology (e.g. soil moisture sensor, land leveling, hail nets, wind machines)	Vegetables	Northeast, Southeast, Midwest, Southwest, Southern Plains	Nicholas and Durham (2012), Jemison et al (2014), van Dijl et al (2015), Mase et al (2017), Skevas et al (2022)
Financial management	Crop insurance	Vegetables	Northeast	Warner et al (2017), Linder and Campbell-Arvai (2021), Schattman et al (2021), Skevas et al (2022)
States surveyed by reference studies:
Northeast: New York (Sweet et al 2017, Lane et al 2018), Pennsylvania (Lane et al 2018), Vermont (Schattman et al 2016, Schattman et al 2021), Maine (Jemison et al 2014), Massachusetts (Warner et al 2017).
Southeast: Florida (van Dijl et al 2015).
Midwest: General (Mase et al 2017), Nebraska (Knutson et al 2011, Mase et al 2017), Michigan (Doll et al 2017, Linder and Campbell-Arvai 2021), Missouri (Skevas et al 2022).
Southern Plains: Kansas (Mase et al 2017).
Northwest: Oregon (Roesch-McNally et al 2020).
Southwest: Arizona (Vásquez-León et al 2003), California (Nicholas and Durham 2012).

Among a wide range of adaptation actions undertaken by farmers, irrigation is the most common strategy. Irrigation can mitigate the impacts of warming temperatures and rainfall variabilities induced by climate change. Depending on local contexts, farmers are adopting various types of irrigation techniques, such as traditional irrigation (Jemison et al 2014, Schattman et al 2021), drip irrigation (Roesch-McNally et al 2020), gravity and sprinkler irrigation (van Dijl et al 2015). However, irrigation alone is not sufficient to tackle climate risks. For instance, Jemison et al (2014) found fruit growers sharing concerns that the warming temperature will severely impact blueberry production in Maine, even with irrigation. As a result, farmers bundle up multiple adaptation strategies to tackle climate-related uncertainties. Roesch-McNally et al (2020), for example, found that farmers in Oregon not only increased irrigation but also improved soil conditions through nutrient management and shifted planting dates. Among other adaptation actions, crop diversification is widely adopted. These studies did not explicitly report the diversified crops per se, but most often, this diversification is a combination of the main growing crops with vegetables, fruits, pasture or hay, or non-food agriculture (e.g. dairy, poultry). Farmers' adaptation actions in the US often are more reactive than proactive, as found by Linder and Campbell-Arvai (2021). They argued that the farmers in Michigan 'take things as they come' and 'roll with the changes'. Similarly, Nicholas and Durham (2012) reported that farmers in California undertake reactive adaptation actions and if proactive, they undertake short-term actions.

3.2. Theme 2: exploring potential adaptations

3.3. Theme 3: evaluating specific adaptation options

3.4. Theme 4: challenges of adaptations

3.5. Theme 5: perceptions toward adaptations

This study reveals that studies published on farmers' adaptations in the US agriculture context are primarily clustered around evaluating specific adaptation strategies while reporting on-farm adaptations or examining the challenges of adaptations did not get much attention. An equal distribution of the studies among these themes is not expected, but a skewed distribution indicates a greater need for research under certain themes. This study found that the majority of the on-farm adaptation-related studies concentrated on the Northeast part of the country and examined a range of adaptation actions undertaken by farmers. However, similar studies on wheat, corn, and soybean zones in the US are scant, and thus, we have limited knowledge of what crop-wise adaptation strategies farmers are undertaking in these zones to tackle climate change-induced challenges. Majority of the studies that reported on-farm adaptations are based on small samples and thus their findings often cannot be generalized. Large-N studies that address crop-wise adaptations are required to address this gap (Lane et al 2018). Future works can further focus on the role of climate change-induced extreme weather events in undertaking adaptation actions by farmers and compare between adaptations by smaller-scale farmers and large-scale farmers (Mase et al 2017). Furthermore, while reporting on-farm adaptations, existing studies did not differentiate among farmers based on ethnicity. Racial inequities can influence the relationship between public agencies and farmers (Furman et al 2014), which can further impact farmers' adaptations. As such, it is important to understand whether ethnicity plays a role in determining adaptations by farmers and to what extent.

Not all adaptation actions can be similarly beneficial or regionally suitable (Yu et al 2021). Thus, it is crucial to identify and evaluate effective adaptations. Several studies evaluated agricultural practices and recommended some strategies as adaptations, such as zero tillage (Eeswaran et al 2021) and modifying planting dates (Franke et al 2022) are effective in diminishing yield losses. Additionally, the articles that did not discuss adaptation per se but focused on evaluating specific conservation or climate-smart practices (e.g. cover crops, use of a particular fertilizer) examined those practices closely. These studies provide a rich understanding of the implications of different types of agricultural practices that are framed as climate-smart agriculture, sustainable agriculture, conservation agriculture, and agricultural adaptations. These practices are often influenced by local institutions, normative, and infrastructural conditions (Cody 2018). Future works should include direct and indirect measures of the usefulness of adaptation actions under different institutional and infrastructural conditions. While evaluating adaptation actions, the majority of the studies did not incorporate market dynamics in the analysis; but an agricultural practice or action will not be adopted by farmers unless it generates higher profit than the current practice or it is incentivized in some way. Therefore, it is important to integrate variables related to market dynamics in the modeling approach. Additionally, in future climate change scenarios, it is crucial to incorporate future socioeconomic scenarios in order to capture farmers' adaptation behavior (Antle et al 2017). Recent global projection scenarios (i.e. Shared-Socioeconomic Pathways) might be somewhat useful, yet simulating farmers' behavior based on behavior models in decision-making science has a greater potential to be more effective in climate change scenarios (see Schlüter et al 2017 for behavior models). In future climate change scenarios, a potential source of error may arise from assuming no change in vegetation cover (Brown et al 2019). Future works should attempt to incorporate the changes in vegetation and their relationships with water yield into their analysis to better estimate water availability. Similarly, in the modeling approach, considering carbon dioxide-induced fertilization can provide more accurate estimates of adaptation actions, as Attavanich and McCarl (2014) showed that different crops respond differently to elevated carbon dioxide levels. Thus, further crop-specific analyses on adaptations incorporating these complex dynamics are warranted (Olen et al 2016).

Irrigation has been the focus of the studies that evaluate specific adaptation strategies. In the US, access to irrigation water mostly depends on water regulations rather than the physical availability of water (Lauffenburger et al 2022). Thus, water availability is often parameterized in models as crop water use by farmers instead of streamflow (Maneta et al 2020, Lauffenburger et al 2022). For better analysis, future works on adaptations under different irrigation regimes need to capture the biophysical effects of climate change as well as the institutional controls on water availability (Malek et al 2020). Irrigation expansion has been suggested by many as an adaptation strategy (e.g. Ward and Crawford 2016, Rosa et al 2020), yet further work are required on downscaled opportunities and limitations of irrigation expansions (Troy et al 2015, Rising and Devineni 2020). At the same time, irrigation expansion needs to be done carefully as increasing irrigation can cause greater emissions of greenhouse gases. McGill et al (2018) found that compared to a rainfed system, an irrigated system produces 45% more greenhouse gas emissions, but it can also sequester 7% additional carbon by increasing soil organic carbon storage capacity. Additionally, examining the synergistic effects of multiple adaptation practices on the biophysical properties of soils as well as farmers' adaptive capacities are essential (Steiner et al 2018, Huang et al 2020). While exploring potential adaptations and assessing adaptation practices are crucial, it is also important to address how policies impact farmers' adaptations or dictate certain adaptation practices (e.g. irrigation) and how to best accomplish the integration of scientific information with governance (Schattman et al 2021). Integration of scientific information into long-term decision-making can be accomplished when the decision-makers perceive the information as accurate, credible, reliable, useful, and timely (Kirchhoff et al 2013). A wide variety of agricultural or crop models has been used to analyze the impacts of adaptations on crop production and each model has its own limitations. Future works should address those limitations before adopting those models (Anandhi 2017, Antle et al 2018). Future research can address high-resolution, locally downscaled data availability and accuracy and the challenges of incorporating the information into decision-making (Gillon et al 2016). Similarly, future research can analyze whether state-level governance approaches enable farmers to make effective adaptation decisions and whether these approaches are capable of protecting farmers during extreme weather events (Schattman et al 2021).

The studies that focused on the challenges of adaptation documented a lack of training and information as well as farmers' denial of climate change as barriers to adaptation. We need more evidence of challenges or barriers to adopting certain practices by the farmers. For instance, because of climate change impacts, farmers are adopting practices to improve soil health in the Northwest US, and it is important to understand the barriers to the adoption of these practices and develop approaches to overcome these barriers (Yorgey et al 2017). Cover crops can provide significant benefits to farmers against climate change impacts, yet it is poorly adopted across the US (Yoder et al 2021). Future works can emphasize how barriers to the adoption of such adaptation practices could be addressed and how incentives could be provided to minimize abandonments. Eeswaran et al (2021) found that organic and no-till farming are climate resilient for food crops and provide great revenues to farmers than conventional methods of farming. Yet, why the migration to organic farming did not happen faster has been explored a little. Also, further research is required on identifying and exploring strategies to address farmers' psychological barriers, existing market structures that are not favorable to organic farming, and reducing the transition cost. While we need more analysis of these kinds, we also need to examine if minority farmers encounter greater challenges. A great majority of the farmers in the US are white males, yet it is important to focus on minority farmers because inequities and discrimination can lead to agricultural abandonment by them. Studies show that black farmers experience hurdles to operating farms because of a lack of access to credit, relegation to marginal hazard-prone lands and women farmers generate less income than men farmers (Taylor 2018, Horst and Marion 2019). Similarly, future works can analyze if the challenges associated with adaptations vary between large-scale and smaller-scale farmers.

Technological innovations increased our capacity to tackle climate change impacts on agriculture with greater efficiency. Yet, more studies are required on how recent technological innovations are assisting farmers in adapting to climate change impacts. How climate-smart technologies, satellite remote sensing, drones, big data, artificial intelligence, and machine learning can be used responsibly in farmer adaptations need to be explored more. Additionally, it is important to focus on how the overall food production and supply chains can be made more robust to increase resilience against extreme weather events as well as longer-term climate impacts (Mehrabi et al 2022). Producing around 30% of maize and soybeans and around 10% of wheat globally, the US is one of the leading food producers in the world (FAO 2020). Increasing the resilience of food production through effective adaptation is crucial not only for national food security but also for global food security.

Although many studies addressed farmers' adaptation in US agriculture from various angles, a comprehensive view of the adaptation research activities was absent. The main purpose of this study is to map out the current research trends in adaptation literature that focuses on US agriculture. This study systematically reviewed peer-reviewed English language articles and found that the existing research on agricultural adaptation in the US can be categorized into five broad themes. This study found that irrigation is the most common adaptation strategy across the US, and farmers adopted various irrigation techniques, including traditional, micro, and drip irrigation. Adaptation studies that focus on evaluating specific adaptation measures primarily deal with the performance of irrigation. However, farmers also take other adaptation strategies, but many farmers, if not most, undertake more reactive strategies than proactive ones. This may happen due to their perception of climate change. The farmers who believe in anthropogenic roles in climate change are more likely to support individual and government-supported adaptations. Overall, this study found that more research has been conducted on exploring potential adaptations or evaluating the performance of specific adaptations than other themes. This finding indicates the need for more attention to documenting on-farm adaptation strategies and the associated challenges while emphasizing other themes. This study acknowledges two limitations. First, there is a plethora of research in different disciplines that focus on issues related to climate change adaptation without explicitly mentioning the term. Those research works were not considered in this study. Second, many studies analyzed the impacts of climate change on crop yield and suggested various adaptation strategies. As adaptation was not the primary focus or data-informed findings of those articles, this study did not take them into account. Future studies can address these limitations by considering those studies into their analyses.

No new data were created or analyzed in this study.

No competing interest.

Asif Ishtiaque developed the research plan, formulated research design, analyzed data, and prepared the manuscript.

This research received no funding from any organization.