Materials and methods

To understand the perspectives and concerns of current palynology, we identified peer-reviewed scientific papers from two theoretical principles in Quaternary botany: a) species respond in an individualistic way to environmental changes (Gleasonian aspects), and b) pollen assemblages to explain stochastic processes such as disturbance and historical legacies (Clementsian ideas) (^{Vegas-Vilarrúbia et al. 2011}, ^{Birks 2019}).

In this context, pollen assemblages refer to a landscape mosaic of different communities or vegetation types (^{Birks 2019}). As mentioned by ^{Jackson & Blois (2015)}, a spatial mosaic of communities is determined by random processes such as seed dispersal or patch dynamics in the composition of Holocene forest communities rather than environment assembly (physiological and demographic responses to the physical environment) as the only possible explanation. This idea has brought with it that the concept of “community” in Quaternary palaeoecology must consider aspects such as pollen production, dispersal, and taphonomy to avoid mismatches between data and applications (^{Kidwell & Flessa 1995}, ^{Jackson & Blois 2015}). Although the Gleasonian approach has mostly considered climatic factors (at the species level) rather than historical contingencies and cross-scale interactions (at a community level), both perspectives have shared ideas. However, it was ignored mainly among pioneers of Quaternary botany (^{Birks 2019}).

We revised scientific literature and consulted the Web of Science and Scopus databases (^{Zhu & Liu 2020}) to recognize some innovative applications. We searched with the keyword filters: pollen viability/quality, palynological techniques, cryopreservation, melissopalynology, historical ecology, ecosystems services, and food security or agrobiodiversity that should be featured in topics and titles methods, keywords, and abstracts during the last 30 years at least. This period coincided with soil quality definitions, including biological productivity, environmental quality, and plant, animal, and human health, whereas definitions before 1990 only considered productivity and suitability for crop growth (^{Bünemann et al. 2018}). In addition, the scientific manuscripts need to accomplish some requirements, such as rural development projects, biological corridors, adaptive management, multifunctional landscapes, and forest restoration.

Results

We obtained palynological perspectives from the scientific literature review done: evolutionary-ecological and interdisciplinary research (Table 1). We delimited the first perspective with practical and exclusive applications of botany in globalized agriculture systems, such as the cryopreservation of pollen grains for the balance of "ex situ" and "in situ" conservation, pollinator monitoring, and the role of fossil pollen databases for "inter situ" restoration. We observed that most of these scientific papers had been applied within taxonomic categories like genus, species, or populations (e.g., code/accession, germplasm, population genetics, population ecology, landrace, cytological experiments). Therefore, we have also considered the above applications as part of the ecological and evolutionary perspective.

Some palynological applications have incorporated studies such as agrobiodiversity conservation and preservation of native species in the Anthropocene into ecological and evolutionary perspectives (^{Mourelle et al. 2016}, ^{Silva et al. 2018}). This research has shown that biodiversity conservation can provide ecosystem services to agriculture. At the same time, integrated management encompasses the nexus of food, non-food, and natural resources to develop local and regional sustainable agriculture (^{Therond et al. 2017}, ^{Zimmerer et al. 2019}). The relevance of this evolutionary and ecological perspective is mainly focused on the transition from global to sustainable agricultural systems, including plant breeding programs and the cooperation between companies and government institutions (^{Padureanu & Patras 2018}, ^{Silva et al. 2018}). On the other hand, avian palynology studies suggest that commercial and garden flowering trees are an essential resource for migrating warblers based on foraging preferences by palynological techniques (^{Wood et al. 2014}). Similar studies emphasize the importance of pollinators in the conservation of native forests for multiple ecosystem services such as crops (^{Borgella et al. 2001}, ^{Matias et al. 2019}). In other words, current palynology has embraced approaches from species to communities (^{Vegas-Vilarrúbia et al. 2011}, ^{Birks 2019}).

Moreover, we found that specific palynological studies included socio-ecological approaches and historical ecology studies for sustainability. 1) The conservation of agrobiodiversity using melissopalynology and its relevance to the alternative food systems in Palawan, Philippines (^{Matias et al. 2019}), 2) the legacy of agroforestry of Western Ghats, India (^{Nogué et al. 2018}), and 3) the landscape transformation of central Italy during the Roman period based on archaeological evidence and its biogeographical implications (Figure 1) (^{Mensing et al. 2018}). Therefore, from an interdisciplinary perspective, we mentioned that those palynological scientific papers had interconnected with other disciplines (e.g., geochemistry, paleoclimatology, biogeography, archaeology, socio-ecological research).

Figure 1 Historical legacies and patch dynamics by using pollen analysis. 

In this context, novel landscapes, including native and non-native ecosystems, have had an essential role in biodiversity conservation. According to the Food and Agriculture Organization of the United Nations (FAO) and the World Food Summit (^{FAO 1996}), food security, which can be identified as the availability and access of food, dietary needs, and stability as a synonym of sustainability, has experienced four-dimensional evolution over the last three decades. Food security has evolved by the inclusion of some international programs such as ^{The Millennium Ecosystem Assessment (2005)}. This framework underpins food demand and availability in response to biodiversity loss, land cover change, and future climate scenarios (^{Jeffers et al. 2015}). In this sense, food systems have emerged to underscore the importance of sustainable agriculture to climate change because this relationship facilitates actions in favor of integrated landscape management (^{Scherr et al. 2012}). The components of agricultural landscape management may include protecting natural areas, restoring hydrographic basins, climate-friendly livestock systems, and others (^{Scherr et al. 2012}). Consequently, several authors have emphasized the importance of crucial landscape components on different scales to achieve social, economic, and ecological impacts for multi-stakeholder planning (^{Scherr et al. 2012}, ^{Therond et al. 2017}, ^{Zimmerer et al. 2019}).

The essential palynological perspectives and applications come from different farming systems. They incorporate a wide variety of short- and long-term measurements, including palynological descriptions to decrease chemical inputs in monocultures, melissopalynological studies for landscape management using mobile-agent-based ecosystem services (MABES), and historical ecology approaches to identify agricultural landscapes that transform but maintain biodiversity, such as agroforestry techniques (^{Nogué et al. 2018}, ^{Padureanu & Patras 2018}, ^{Matias et al. 2019}). These practical studies are frequently done in certain regions in Asia-Pacific, Europe, and North and South America, such as strategies for mitigation and adaptation to climate change.

We obtained examples of palynological applications in two models of agriculture: chemical input-based farming systems and biodiversity-based farming systems (Figure 2). We identified some benefits between ecosystem services in monocultures, such as germplasm programs for livestock and control of soil erosion. In addition, we also recognized trade-offs between ecosystem services (e.g., the relevance of aquatic systems in the restoration of temperate forests) through indicators of soil quality using palynomorphs and historical ecology. These palynological applications are part of projects that may be important for transitions between agricultural systems for sustainable development as well as for the management of non-timber resources such as honey. On the other hand, as discussed below, we present the perspectives and development of palynology towards sustainability.

Figure 2 Palynological applications in current plant breeding (pollen morphology) and landscape management (melissopalynology and Quaternary botany). 

Discussion

Palynology: an evolutionary and ecological perspective. Although the fundamental principles of pollination have probably existed since Assyrian times (the earliest Neolithic sites date from c. 9000 to c. 7000 years B.P.), the significant breakthroughs in the evolution and ontogeny of pollen grains began in the middle of the last century with innovations in SEM, TEM, and LM microscopy (^{Halbritter et al. 2018}, ^{Chen et al. 2019}). Subsequently, a critical age of palynology began with describing the process of microsporogenesis through the Tapetum (^{Blackmore et al. 2007}) and its relationship with the detection of germplasm resources in both natural habitats and agrobiodiversity systems (^{Souza et al. 2017}, ^{Silva et al. 2018}).

The cytological and palynological characteristics that can be studied through the formation of the microspores are morphology, viability, and pollen production. The morphology of the pollen wall is essential, among other things, to correlate the type of ornamentation with reproductive strategies, as in some invasive plants (^{Syamsuardi et al. 2018}). For instance, ^{Kolczyk et al. (2015}) demonstrated that some cytological features, such as the regular and proper course of meiosis and high viability of pollen grains, lead to the formation of aggressive weedy races that can colonize highly disturbed ecological habitats. In Quaternary botany, palynological records provide a reliable approach to determining the native or introduced status of a species in a particular region (^{Birks 2019}). Such an approach has found that some doubtfully invasive species are, in fact, native to the Galapagos archipelago and possibly in other regions in the Pacific (^{van Leeuwen et al. 2008}). This information would result in relevant strategies for conserving and restoring natural ecosystems related to biological invasions (^{Froyd & Willis 2008}, ^{Birks 2019}).

Moreover, the comparative pollen morphology and seed germination studies in Retama raetam ssp. gussonei (Fabaceae) discriminate the relevance of palynology in practical conservation actions for dune stabilization and renaturation of desert areas (^{Ferrauto et al. 2015}). Similar approaches can be applied in vulnerable endemic populations such as epiphytic angiosperms (Bromeliaceae), which are commonly threatened by loss of pollinators, poaching and habitat isolation (^{Palma-Silva et al. 2008}). In fragmented ecosystems, ^{Aizen & Feinsinger (1994)} showed that there was a reduction in number of pollen tubes that are responsible for fertilization in some tree species due to geographic isolation. In contrast, ^{Mourelle et al. (2016)} found that two native South American Butia palms (Arecaceae) produce two pollen grain types, which has been considered a derivation. Despite habitat fragmentation, pollen viability was high enough to ensure pollination; therefore, viability is not the limiting factor for conservation of pollen grains, but intra-or inter-specific morphological differences in populations and habitat fragmentation should be considered to ensure effective pollination (^{Mourelle et al. 2016}).

The palynological applications also provide economic and ecological value mainly in the Poaceae family due to their use as forage for animal feeding and erosion protection (^{Silva et al. 2018}). The accessions comparisons among species of the genus Cynodon (Poaceae) are critical for elucidating some exine patterns, meiotic abnormalities, morphological apertures, and pollen viability from germplasm banks (^{Silva et al. 2018}). Although the Erdtman acetolysis provides enough information on dispersal's ecological and evolutionary characteristics in many angiosperms, additional alternative techniques are recommended in fragile pollen grains (e.g., methods based on enzymatic treatments) to avoid changes in morphology (^{Silva et al. 2018}). Furthermore, ^{Padureanu & Patras (2018)} performed a palynological characterization among hybrids in the genus Vitis (Vitaceae) to understand the relationships between morphology, germination potential, and pollen tube growth in the fertility of grapevines. In their study, they demonstrated that more homogeneous pollen size and tricolporate apertures positively affect the degree of fertility from pollen grains in different genotypes of vineyards. Recently, these investigations have been commonly applied in globalized agriculture systems to decrease external inputs (e.g., fertilizers or pesticides) and increase the adoption of integrated crop-livestock systems along with conservation agriculture towards sustainability (^{Therond et al. 2017}).

Plant breeding programs may be necessary to complete climate change mitigation actions (^{Souza et al. 2017}, ^{Silva et al. 2018}). ^{De Haan et al. (2013)} demonstrated the complementary nature of both "in situ" and "ex situ" conservation strategies from the Potato landrace cultivar collection in Peru. According to ^{De Haan et al. (2013)}, the ex situ conservation will ensure the availability and use of unique genetic diversity, while in situ management will result in responsive evolution facilitating adaptation to changing environments. For these reasons, palynological applications of pollen grains take an essential role in germplasm banks, landrace, genotypes, and wild accessions for cryopreservation. Although both in situ and ex situ conservation are significant advances in ecology and evolution, ^{Zimmerer et al. (2019)} proposed more rigorous methodologies and innovative estimation techniques for monitoring agrobiodiversity, including stakeholder engagement. In practice, palaeoecological records provide information for such strategies by considering the ecological tolerance and ability to thrive in microrefugia for several plants (^{Vegas-Vilarrúbia et al. 2011}).

Beyond the conservation of agrobiodiversity, alternative practices can be employed to restore natural habitats or abandoned agricultural lands using palynological tools. Inter-situ restoration, the establishment of species by their reintroduction to locations outside the current range but within the recent past range of the species, involves horticultural and agricultural techniques for the conservation of natural habitats (^{Burney & Piggot 2007}). In fact, this type of restoration uses a list of fossil pollen that comes from adjacent sites to maintain the functions of the target ecosystem (^{Burney & Piggot 2007}). For instance, ^{Burney & Piggot (2007)} documented the scope of inter-situ restoration of native palms because their seeds and pollen were abundant in pre-human sediments excavated from the Hawaiian Islands. Although the ex situ conservation of pollen diversity in botanical gardens (^{Sudarmono 2019}), as well as the reintroduction of native species, may be important in the regeneration of natural habitats (^{Burney & Piggot 2007}, ^{Jackson & Hobbs 2009}), certain aspects, such as the conservation of pollinators, can also be crucial. The research of ^{Rodríguez-Riaño et al. (1999)} demonstrated that germination of the pollen grains of some species from the Genisteae tribe occurs only after rupture of the stigmatic surface by tripping due to pollinator action during anthesis. Furthermore, this might be significant in the floral phenology of endemic plants because there is a more significant investment of resources in the perianth than in the reproductive structures, which is logical in flowers that must attract pollinators (^{Rodríguez-Riaño et al. 1999}).

As plant-pollinator interaction will be relevant in conserving diverse landscapes, some palynological applications like pollen loads from mobile agents can play an essential role in fragmented ecosystems. For example, in Neotropical cloud forests, ^{Borgella et al. (2001)} showed that fragments as small as 10 to 20 ha represent valuable habitats for supporting hummingbird populations using pollen loads and species richness. In that study, specialized feeders were commonly found in larger fragments and native forests wherein the maintenance of plant species may be affected if such pollinators are no longer available (^{Borgella et al. 2001}). For these reasons, similar studies are essential for the conservation of biological corridors and their contributions to other ecosystem services such as crops, pest control or habitat preservation (^{Ponnuchamy et al. 2014}, ^{Wood et al. 2014}, ^{Stewart & Dudash 2017}).

Palynology: an interdisciplinary perspective. Recently, two novel approaches have linked palynology within interdisciplinarity: socioecology and historical ecology. The socio-ecological approaches can analyze ecological features of honey as a provisioning MABES through melissopalynology, i.e., the botanical origin and pollen content of honey (^{Matias et al. 2019}). The method can be used for tracing floral phenology across years to understand the foraging preference of pollinators as spatio-temporal factors of interannual projects (^{Ponnuchamy et al. 2014}). Honey production can also be involved in rural development projects based on an integrated landscape approach as part of circular economies in alternative food systems (^{Therond et al. 2017}, ^{Matias et al. 2019}). For these reasons, in some developing countries, melissopalynology as an indicator of land-use intensification as well as the role of some institutions should be a priority for sustainability (^{Matias et al. 2019}).

Historical ecology commonly applies palynological tools to understand agricultural legacies as part of environmental history based on paleoecological and archaeological approaches. Paleoecology primarily obtains pollen from sediments as indicators of management intensity, landscape configuration, vegetation cover changes, and plant functional groups (^{Johnson & Miyanishi 2008}, ^{Nogué et al. 2018}). In contrast, archaeology explores palynomorphs to explain the relationships between climate change and cultural development using archival documents over the last 3,000 years (^{Szabó 2015}, ^{Mensing et al. 2018}). Therefore, the following discussion provides the relevance of palynology by means of the socio-ecological and historical approaches.

Melissopalynology in agrobiodiversity conservation.- Ecological restoration is a type of subdiscipline that facilitates biodiversity conservation (^{Young 2000}). Melissopalynology can be a powerful strategy in integrated conservation efforts in the interests of forest restoration while emphasizing the multiple ecosystem services (e.g., crop pollination, reproduction of wild plants) provided by honeybees (^{Kremen et al. 2007}, ^{Matias et al. 2019}). In the Philippines, some indigenous communities have transformed the traditional non-timber forest product (NTFP) into community forestry enterprises for subsistence (Matias et al. 2019). For instance, ^{Matias et al. (2019)} demonstrated that including melissopalynology, household surveys, and key informant interviews sufficed to recognize the role of different national and international institutions for sustainability. Furthermore, they discussed the relevance of the landscape approach to accessing higher-value markets based on the organic characteristics of honey that may prompt the creation of management policies to maintain ecosystem services and functions (^{Matias et al. 2019}). Research also examined the relationships between the foraging preferences of giant honeybees (Apis dorsata) and honey gathering as the social and ecological features of a system to detect fertilizers and chemical pesticides harmful to bees (^{Matias et al. 2019}). Physicochemical and melissopalynological studies are complementary tests accepted by the Codex Alimentarius Commission and the International Honey Commission, among others, to assess the natural quality and honey botanical origin (^{Alfaro-Bates et al. 2010}).

This approach is an example of alternative food system landscape management in a sustainable development framework as it increases the degree of ecosystem services and territorial embeddedness (^{Therond et al. 2017}). In addition, the inclusion of some institutions, such as FAO and the World Health Organization (WHO), are usually indispensable to protect consumer health and promote fair practices in the food trade. In this context, biodiversity and ecosystem services can be adequately employed in terms of landscape management and restoration due to multilayered relationships (^{Mace et al. 2012}). The apiculture, honey bees, and meliponiculture have ecological implications in some countries such as Argentina, Mexico, the United States, China, and Turkey. They are the biggest honey producers globally (^{Ramirez-Arriaga et al. 2016}).

The legacy of agroforestry.- The palaeoecological approach encompasses two main factors in environmental history: land-use intensification and plant cover changes (^{Bürgi et al. 2017}). Magnetic mineralogy of soils is a powerful tool to identify cultural practices such as "slash and burn"; commonly practiced in sites with high levels of deforestation (^{Evans & Heller 2003}). In contrast, plant cover changes are usually studied by means of paleoenvironmental indicators such as pollen and other palynomorphs that are related to peopling and agriculture (^{Haas et al. 2013}, ^{Acosta et al. 2018}, ^{Nogué et al. 2018}).

However, the research of ^{Nogué et al. (2018)} explored the relevancy of agroforestry as a practice that has contributed to the maintenance of tropical forests for the last 900 years (Figure 1). They used pollen as an indicator of past changes in vegetation and macroscopic charcoal as an indicator of biomass burning to identify the persistence of habitat-specialist trees over time. In that study, the results showed that sacred groves increased the forested habitat during the last 300 years, whereas agroforestry plantations displayed different trajectories between 800 and 50 cal. years B.P. Additionally, research suggests that some ecosystem services of provision and worship were sociocultural drivers in the persistence of native trees in Western Ghats, India (^{Nogué et al. 2018}).

In some areas of North America, historical ecology has been applied as a tool for understanding long-term changes in agriculture, frequently in agroforestry systems well known as chinampas (^{González-Quintero & Sánchez-Sánchez 1991}, ^{Nichols 2015}). In addition, palaeoecological studies in these wetlands are crucial to promoting conservation strategies because of their relevance to local and regional food systems in Mexico (^{Moreno-Calles et al. 2013}).

Palynology in archaeology and cultural development.- The cultural development of agrarian societies is essential to the reconstruction of the environmental history of ecosystems in the archaeological context. Palynology is also crucial to studying cultural practices (extensive and intensive pastures, crops, and cultivated trees) which have had a decisive impact on current ecosystem services (^{Mazier et al. 2009}, ^{Boivin et al. 2016}, ^{Mensing et al. 2018}). In fact, in some regions of southwestern Amazonia, archaeological research has shown the influence of anthropogenic activity on the creation of artificial forest islands in a seasonally flooded savanna: a human legacy of the Holocene (^{Lombardo et al. 2020}).

^{Mensing et al. (2018)} corroborated that by using essentially-palynological historical indicators at archaeological sites, it was possible to identify land-use changes due to sociopolitical and demographic transformations in Italy during the Roman Period. Although the research underlines the importance of some climatic indicators, such as the North Atlantic Oscillation and the Little Ice Age, ^{Mensing et al. (2018)} concluded that environmental change was more related to human activity than climate change. In the same research, ^{Mensing et al. (2018)} included documentation of non-pollen palynomorphs as indicators of sociopolitical decisions in landscape configuration during the last 2700 years, some of which were: 1) new priorities for wood and meat (Glomus and Sporormiella) as biological recorders of soil erosion and livestock during the medieval period; 2) the afforestation of oaks during the ascent of Charlemagne in the year 774 A.D.; 3) rural land management and agricultural intensification in the mid-9^th century; 4) the medieval practice of coppicing and pollarding in trees between the year 1380 and 1400 A.D.; and 5) the creation of forest laws in the mid-18^th century (^{Mensing et al. 2018}).

Therefore, according to ^{Mensing et al. (2018)}, restoration efforts must consider specific causes of environmental change to manage biodiversity in different localities. For instance, they found that humid conditions in mesic forests (e.g., Alnus, Fagus, Carpinus) were brought about by floodplain wetlands, and therefore restoration of forest ecosystems is not likely to be accomplished without the restoration of alluvial plains. These relationships could be explained by constructing a drainage system that eliminated all the floodplain forest circa 1750 AD and converted former wetlands into permanent agricultural fields with settlements in the Rieti Basin (^{Mensing et al. 2018}). Additionally specific historical events were suggested as highly important to conservation, such as differences in coppicing rotation: medieval and mesolithic practices that facilitate the resprouting of many stems and more rapid forestation (^{Mensing et al. 2018}). Furthermore, cultivated trees (e.g., chestnut, walnut, and olive) and wolf and bear populations' return were also identified as ecosystem services using palynological indicators and archival documents (^{Mensing et al. 2018}).

At this time, coppicing in many woodlands can produce multiple ecosystem services like fuel and food, making it an essential tool for restoration and conservation management (^{Bunting et al. 2016}). The role of these managed woodlands is then to develop synergies between food and energy production to enhance ecosystem services into integrated food-energy systems (^{Therond et al. 2017}). Therefore, multi-service landscape management can provide opportunities to expand biodiversity-based farming systems in circular economies for sustainability (^{Therond et al. 2017}).

Thus, historical ecology is included in the newly emerging discipline known as Agriculture Biogeography, which studies the origins and past geography of crops as well as considering long- and short-term aspects on large and small geographical scales (^{Katinas & Crisci 2018}). Consequently, the palynological component in historical studies may be utilized as a methodological tool to create ecological spaces from the origin of agriculture to the present, thereby adding anthropogenic biomes into landscape approaches, according to ^{Katinas & Crisci (2018)}.

Palaeoecology and archaeology play an essential role in some biogeographic patterns in temperate forests in Europe (^{Divisek et al. 2020}). These predictive models underscore the importance of including fossil pollen as an indicator of past climate changes, human legacies, and biotic characteristics that affect temperate ecosystems' current richness and distribution. ^{Divisek et al. (2020)} showed that by combining environmental and historical data, it was possible to predict the species richness of habitat specialists by thematic maps throughout the Holocene. That study observed that historical factors always appeared among the best predictors of current species richness. They demonstrated that landscape history, anthropogenic disturbances, and temperature seasonality, among others, were important predictors for the current species richness of vascular plants in forests and grasslands of eastern Central Europe. Similar approaches have found modern pollen-vegetation relationships across a landscape mosaic in central Mexico (^{Castro-López et al. 2021}). These pollen-vegetation ratio indices demonstrate local and human disturbances derived from the late Holocene and the last 500 years (Castro-López et al. 2021). In addition, indexes of diversity and dominance provide the representativeness of vegetation types in different landscapes (^{Chang-Martínez & Domínguez-Vázquez 2013}, ^{Castro-López et al. 2021}).

Moreover, the relevance of palaeoecology was to recognize the interactions between different historical factors to understand the variation of biological and biogeographic richness over time. Some of these interactions could be explained by the formation of environmental gradients between forest-steppe and dry steppes in the Middle-Holocene, the expansion of agriculture in the Late Neolithic, and the suppression of organisms by climatic and ecological variations during the last 11,000 years (^{Divisek et al. 2020}). Therefore, these studies have suggested the inclusion of historical factors in ecological modeling and the incorporation of more past climate changes, especially within the Holocene (^{Divisek et al. 2020}).

Future directions for research. One of the significant challenges for palynologists is to create research and strategies for ecosystem management. Long-term approaches and interviews with key stakeholders can provide evidence to address uncertainties in restoration efforts (^{Davies 2011}). Through paleoecology research, stakeholders can recognize the value of the past to balance the practical knowledge required for conservation and restoration goals; for example, whether some practices such as managed grazing or coppiced and pollard trees can enhance the regeneration of woodlands (^{Davies 2011}). In the United Kingdom, these approaches have been implemented to increase the connectivity between woodlands fragments without neglecting natural and cultural factors. ^{Davies (2011)} showed periods of climatic and biotic adversity by using pollen assemblages to detect landowners' positive and negative management practices. Therefore, palaeoecological and palynological data can improve stakeholder expectations by recognizing historical legacies. This means that future directions for research must recognize different historical legacies of adaptive management (^{Davies 2011}). Interdisciplinary approaches to paleoecology must incorporate quantitative contributions of microenvironmental variables, anthropogenic disturbances, and past climate changes as a strategy for adaptation to climate change.

Palynology and archaeobotany studies will have implications in developing countries, where social and ecological approaches play an essential role in conservation efforts. A clear example is a case of calling for the recognition of indigenous rights in Amazonia as a policy of ecosystem conservation (^{Franco-Moraes et al. 2019}). These investigations have considered human management as an indicator of the maintenance of plant biomass and biodiversity composition that positively impact soil quality in ancestral forests (^{Franco-Moraes et al. 2019}). Historical legacies of management practices are commonly studied by using oral histories, floristic inventories, ethnobotany, and edaphic variables, which can be implemented along with palynological experiments; however, pollen and other sources require special conditions for preservation (^{Franco-Moraes et al. 2019}). Although it can be challenging to collect historical sources, the interdisciplinary perspective and landscape approach can make the goals of many projects feasible. For example, the forest with nutrient-poor soils (^{Franco-Moraes et al. 2019}) as well as fertile soils, such as "Terra preta del Indio" (^{Bush & Silman 2007}), can be a framework in neotropical regions with similar pluriethnic systems (^{Vegas-Vilarrúbia et al. 2011}).

Finally, one challenge is generating predictive models, using paleoecology and biogeography to identify the percentages of current plant community distribution patterns, precisely because these measures contribute to the detection of synergistic effects between human impact and the environmental history of ecosystems. Therefore, modern pollen rain studies and paleoecology databases will be essential for applying diversity analysis and their implications for other experimental investigations into natural habitats (^{Jantz et al. 2014}). On the other hand, palynological techniques to identify pollen grains from different floral resources will be crucial for cryopreservation, so alternative methods to decrease costs will be significant (^{Silva et al. 2018}). Future lines of research have also considered topics such as mountain palaeoecology, archaeopalynology, agroforestry palynology for food security, and palaeoecology of historical legacies.

This review made it possible to recognize palynological perspectives: ecological evolution followed by interdisciplinary research. The genetic improvement of monocultures by means of palynological analyses is indispensable to understanding not only the trade-offs of ecosystem services but also the possibility of food system transitions for sustainability. Greater involvement of palynology can acquire fantastic value for the application of germplasm sources between ex situ and in situ conservation of agrobiodiversity and ecological restoration in natural and abandoned habitats.

Soil quality assessment using palynomorphs can support adaptive management of ecosystems by integrating aquatic and terrestrial systems. This interdisciplinary perspective also supports management strategies using the MABES framework because it includes multiple environmental services in a landscape approach. For these reasons, long- and short-term studies that include palynology have proven to help generate climate change adaptation and mitigation strategies. We conclude that the most critical aspect of palynology in food security and the conservation of biodiversity is the participatory inclusion of actors and stakeholders because they play a strategic role in the management and study of novel and natural ecosystems.