The Role of Pollen and Pollinators in Long-term Conservation Strategies of Plant Genetic Resources Jan Engels and Ehsan Dulloo Genetic Resources Management Advisor Bioversity International Rome, Italy
Overview of presentation Assessing importance, threats and opportunities of pollen, pollinators and pollination services: Importance in day to day life Threats to pollinators and pollination services Problems and constraints using pollen and pollinators in (ex situ) conservation Opportunities for pollen, pollinators and pollination services in conservation Complementary conservation approach Conclusions
Introduction - Current global scenario: Ever increasing human population Need for more and better quality food Competition for land and land uses; over-exploitation of natural resources; deforestation; desertification; etc. Intensification and other drastic changes in agriculture Dramatic loss of (agro-)biodiversity climate change and other challenges Need to keep options open for future generations In order to mitigate these negative impacts, more effective conservation strategies for biodiversity, incl. genetic diversity and its processes are needed In such strategies pollen, pollinators and pollination processes (should) play an important role
Importance of pollen, pollinators and pollination services (1) Agricultural production Food/crop production (orchards, horticulture, forages) Plant breeding, selection and crop development About 35% global crop production relies on animal pollinators; of major food crops, 13% entirely; 30% greatly and 27% moderately About 80% of flowering plants are specialized to be pollinated by animals (mostly insects) Most plants are pollinated by variable suites of pollinators; but with exceptions (i.e. 750 fig spp, each have their own wasp sp.!) Pollinator diversity essential for sustainable pollination services
Importance of pollen, pollinators and pollination services (2) (Agro-)ecosystem services Exposure of modern crops to pollinators (re-)introduces a lost selective influence to maintain genetic diversity in a crop Bees (>25,000 spp!), moths, flies, wasps, beetles and butterflies are effective pollinators and make up majority of pollinating species Insect pollination count for 95% of canopy trees in the tropical rainforests of Central America; but decreases in lower forest strata Good pollination improved fruit and fiber quality; higher yields of oil (biofuels); increased ripening speed; more effective pyrethrum etc. In general, they support evolutionary + ecological processes!
Importance of pollen, pollinators and pollination services (3) Human health related aspects Medicinal and nutritional value Cause of allergies Commercial considerations Pollination services (commercial + wild) estimated to be $112-200 billion US$ annually food stuff (honey), medicine, etc Thus, pollinators and pollination services are critically important for food security, food diversity, nutrition, economy/poverty alleviation, etc.
Threats to pollen, pollinators and pollination services General loss of natural habitats Loss of pollination services to agriculture (forest fragments provide bee diversity and pollination service in Costa Rican coffee ) Falling bee diversity in 80% of studied sites as well as decline in wildflowers in EUR Intensification of agriculture Significant loss of genetic (bio-)diversity in agro-ecosystems Loss of pollinators and pollinator diversity (eg pesticides, monocultures) Reduction in reproductive success, crop yields and quality! Diseases/problems among pollinators (e.g. Colony Collapse Disorder!) Many good reasons to conserve pollinators and pollination processes (i.e. in situ)
Problems and constraints to use pollen and pollinators for ex situ conservation strategies (1) For a long period ex situ conservation (in genebanks) was strongly focused on major food crops and orthodox seed (e.g. cereals, pulses); techniques biased Inclusion on in vitro techniques (70s and 80s) and on-farm and in situ conservation approaches (80s and 90s) required a re-focus Consequently, until today very limited targeted use of pollen in ex situ conservation; predominantly used in forest and (fruit) tree GR programmes Poorly understood interrelationships between biodiversity, (agro-)ecosystems and pollination services
Problems and constraints of using pollen and pollinators in ex situ conservation strategies (2) Very limited knowledge of flower biology, ecology and possibly even of existing technical guidelines! Usually, only plant material (and related information) is collected for ex situ conservation; what about pollinators? Some species do not produce pollen or only limited amounts Collecting pollen can be very difficult (and costly) Recalcitrance in pollen exists (i.e. not storable) To keep genetic identity of an accession might be difficult when using pollen for conservation purposes Only paternal part of genome transmitted/ represented sex linked genes might be lost; lack of transmission of organelle genomes Not all species produce calli from anthers limitations to regenerate plants
Problems and constraints using pollinators in ex situ conservation strategies (3) Aspects of ex situ conservation (regeneration) problems that relate to pollination/pollinators: Reproductive biology knowledge of minor crops and even of major crops usually insufficient for good genebank management Knowledge of genetics of crops limited poor management Lack of adequate isolation techniques/infrastructure for regeneration Insufficient knowledge of which (insect) pollinators to use Hardly any knowledge of managing pollinators and pollination Relatively high cost of regenerating cross-pollinated species Pre-conditions for adequate ex situ conservation (especially regeneration) are often NOT met by genebanks, in order to regenerate germplasm accessions without loosing integrity
Opportunities of pollen, pollinators and pollination services for conservation Increased recognition of importance of subject (also politically: CBD; Commission on GRFA; governments; etc.) Widening of conservation scope and approaches Conservation programmes cover various sectors In situ and ex situ conservation combined (CWRs; FGR; etc.) Increased eco-systematic thinking/approaches Stronger integration of conservation and development Improved techniques (e.g. genomics, genetic markers) available, incl. use of pollen traps (research + collecting) Recognition by curators to manage pollinators as integral component of germplasm maintenance is increasing Efficiency considerations (in production and conservation)
Identifying opportunities for pollinators and pollination services through research Some examples of such research results: Breeding varieties for attractiveness to pollinators (e.g. production of nectar in melon) can be important Staggered maize flowering through choice of varieties with different flowering periods prolonged flowering season and thus survival of pollinator populations Increasing landscape heterogeneity (i.e. the presence of nearby natural or uncultivated habitats) is an important factor in maintaining pollination services to agriculture (e.g. coffee in Costa Rica; canola in Canada; papaya in Kenya)
Opportunities for pollen in (ex situ) conservation Amenable to drying (down to approx. 5% pmc) and longerterm storage (at < 0 C temps.), incl. cryopreservation Seed and pollen recalcitrance are uncorrelated complementarity in conservation! Due to their size and limited fungal or bacterial diseases convenient for distribution (although some viruses do transmit!) For number of crops pollen traditionally used for exchange of genetic diversity among breeders (date/oil palm, coconut) and/or to bridge periods between male/female flowering or different genotypes to-be-crossed; Storage in pollen banks practiced in tree improvement programmes and for some CWRs; considerations for base collections (e.g. yams in W. Africa)
Complementary conservation approach Considering the facts that: ex situ and in situ conservation approaches are duly complementary current conservation activities tend to be strongly focused on individual species, whereas a holistic/ecosystem approach would be more realistic many of the conservation problems (biological, technical, administrative and political) are multi-disciplinary and cross-cutting the conservation of processes might sometimes be more strategic than conserving the products of evolution, agriculture, etc. Integrate pollinators and pollination processes in complementary conservation strategies
Some conclusions Good reasons to use more pollen in ex situ conservation It is essential to have a better understanding of pollinator and pollination functions/services in conserving germplasm : 1. To obtain good (regeneration) results in ex situ (genetic integrity aspects; managing GM material; incl. legal dimension) 2. To ensure proper management of in situ conserved material (i.e. capitalizing on ecosystem functions) To better conserve pollinators, pollination systems and processes we should treat them as integral components More research, inter-disciplinary cooperation, and sharing of information and responsibilities will be required by genebanks, conservation projects, etc Development of practical technical guidelines (and others) on the use of pollinators in in situ and ex situ conservation
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