Plant, animal, forest and aquatic genetic resources for

food and agriculture

• While more than 6 000 plant species have been cultivated for food, fewer than 200 make substantial

1 See Section 1.5 for further information on the various categories of BFA.

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is difficult to quantify. A widely applicable indi-cator for monitoring within-species diversity has yet to be developed. Important dimensions of concern are genetic erosion and genetic vulner-ability at within-species level. Genetic erosion within species has been defined as “the loss of individual genes and the loss of particular com-binations of genes (i.e. of gene complexes) such as those manifested in locally adapted landraces”

(FAO, 1997). The term is sometimes used in a narrow sense, i.e. referring to the loss of genes or alleles, and sometimes in a broader sense, i.e.

referring to the loss of varieties. Genetic vulner-ability has been defined as “the condition that results when a widely planted crop is uniformly susceptible to a pest, pathogen or environmen-tal hazard as a result of its genetic constitution, thereby creating a potential for widespread crop losses” (FAO, 1997).

Indicators of genetic erosion would ideally focus on changes in the frequency of alleles of importance to crop production (and give them more weight than less important ones), provide a measure of the extent of potential loss (e.g. by estimating the fraction of genetic diversity at risk relative to the total diversity) and allow assess-ment of the likelihood of loss over a specific time period in the absence of intervention (FAO, 2010a). Indicators for genetic vulnerability could be based on a number of different population- level attributes, for example differences in levels of resistance to, or tolerance of, actual and poten-tial major pests and diseases or abiotic stresses (ibid.). In the absence of data that can serve as more accurate indicators of genetic vulnerabil-ity, a simple proxy is the extent to which single varieties dominate over large areas of land. This is based on the assumption that genetic vulnera-bility is higher when large areas are cropped with one (or only a few) varieties.³

3 See, for example, Indicator 42 of the monitoring framework for the Second Global Plan of Action for Plant Genetic Resources for Food and Agriculture: “The least number of varieties that together account for 80% of the total area for each of the five most widely cultivated crops” (FAO, 2016m).

The evidence presented in the country reports⁴ prepared for The Second Report on the State of the World’s Plant Genetic Resources for Food and Agriculture (Second SoW-PGRFA) (FAO, 2010a)⁵ indicates that, overall, the diversity present in farmers’ fields has declined and that threats to diversity are increasing (although the situation varies greatly depending on the country, loca-tion, type of production system, etc.). There is considerable consensus that, overall, the shift from traditional production systems utilizing farmers’ varieties/landraces to “modern” pro-duction systems depending on officially released varieties⁶ is leading to genetic erosion. Many farmers’ varieties/landraces are reported to have disappeared or to have become rarer. However, the situation is complex. For example, it appears that many farmers who plant modern varieties also continue to maintain traditional varieties.

Studies of trends in genetic diversity within released varieties also indicate a complex situa-tion, with some reporting no reducsitua-tion, or even increases in diversity over time. Newly adopted varieties can add genetic diversity to an agricul-tural system. However, in some cases they may completely substitute the original ones. The balance of diversity is therefore difficult to assess.

It is also difficult to make definitive statements about trends in genetic vulnerability. However, more than half the country reports prepared for the Second SoW-PGRFA indicate the presence of significant genetic vulnerability.

The diversity of crop wild relatives has decreased in some areas and appears to be particularly threat-ened in places where the climatic conditions are changing but species migration is prevented by ecogeographical barriers.

4 Note that elsewhere in this chapter, unless indicated otherwise, the term “country reports” refers to the country reports submitted as contributions to The State of the World’s Biodiversity for Food and Agriculture. See “About this publication” for additional information.

5 Unless otherwise indicated, the material presented in this subsection is based on this report.

6 In other words, varieties developed and made available by breeding programmes.

4.2.2 Animal genetic resources for food and agriculture

The number of animal species domesticated for use in food and agriculture is relatively small. The Global Databank for Animal Genetic Resources, hosted by FAO, records data on 38 species.⁷ At global level, the status and trends of animal genetic resources for food and agriculture are assessed largely on the basis of summary statis-tics on breed risk status, i.e. the proportions of the world’s breeds that are categorized as being at risk, not at risk, extinct or of unknown risk status according to the classification system used by FAO.⁸ Since 1993, FAO has published global data of this kind in a number of reports, the most recent being Status and trends of animal genetic resources – 2018 (FAO, 2018g).⁹ The approach has some limitations in that it treats all breeds equally regardless of their significance to the overall diversity of the species (or significance in terms of other possible conservation criteria). It also only registers changes when breeds move from one risk-status category to another.Lack of regularly updated data on the size and structure of breed populations is a major practical constraint to the monitoring of risk status in many countries, par-ticularly in the developing regions of the world.¹⁰ Sustainable Development Goal Indicator 2.5.2 is “Proportion of local breeds classified as being at risk, not-at-risk or at unknown level of risk of

7 Some of these are in fact groups of species (e.g. deer) or fertile interspecies crosses (e.g. dromedary × Bactrian camel crosses).

8 Breeds are assigned to risk categories on the basis of the size, structure and trends of their populations. Data are drawn from the Global Databank for Animal Genetic Resources, the backbone of FAO’s Domestic Animal Diversity Information System (DAD-IS). Countries are responsible for entering data on their breed populations into the system.

9 Unless otherwise indicated the data presented in this subsection are taken from this report.

10 In 2013, the Commission on Genetic Resources for Food and Agriculture adopted the following indicators for the diversity of animal genetic resources: the number of locally adapted breeds; the proportion of the total population accounted for by locally adapted and exotic breeds; and the number of breeds classified as at risk, not at risk and unknown. The indicators have not (as of 2018) been fully put into operation because the necessary classification of breeds as locally adapted or exotic has not been completed.

extinction.” As of March 2018, 7 745 breeds out of the 8 803 breeds recorded by FAO were classed as local breeds (i.e. reported present in only one country). A total of 594 local breeds were extinct.

Among extant local breeds, 26 percent were clas-sified as being at risk of extinction, 7 percent as not at risk and 67 percent as being of unknown¹¹ risk status. A comparison of data from 2006 and 2014 shows a slight decrease (29 to 26 percent) in the proportion of local breeds classified as being at risk of extinction.¹² However, the apparent trend needs to be interpreted with caution given the above-mentioned limitations in the state of reporting. Over the same period, the proportion of local breeds with unknown status increased from 62 percent to 67 percent. If all breeds are considered, regardless of whether or not they are classed as local, 59 percent are classed as being of unknown risk status, 10 percent as not at risk, 24 percent as at risk and 7 percent as extinct.

Among the extant species regarded as having been the wild ancestors of major livestock species, the most seriously at risk according to The International Union for Conservation of Nature Red List of Threatened Species^TM (The IUCN Red List)¹³ are the African wild ass (Equus africanus) and the wild Bactrian camel (Camelus ferus), both of which are classified as Critically Endangered.

The wild water buffalo (Bubalus arnee) and the banteng (Bos javanicus) are classified as Endangered. The Indian bison (Bos gaurus), wild yak (Bos mutus), mouflon (Ovis orientalis), wild goat (Capra aegagrus) and swan goose (Anser cyg-noides) are classified as Vulnerable. The European rabbit (Oryctolagus cuniculus) is classified as Near Threatened.¹⁴ Overall, it appears that a higher proportion of livestock wild relative species are threatened with extinction than mammalian and

11 Breeds are considered to be of unknown risk status if no population data have been reported to FAO during the preceding ten years.

12 Both sets of figures were calculated on the basis of the data recorded in DAD-IS as of March 2018.

13 The IUCN Red List of Threatened Species. Version 2018-1.

14 This refers to the status of the wild rabbit in its natural range.

Outside its natural range, the species is widespread and often considered a pest.

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bird species in general. As of 2010, 25 percent of species in order Galliformes (chicken relatives), 83 percent of species in tribe Bovini (cattle rela-tives), 44 percent of species in subfamily Caprinae (sheep and goat relatives) and 50 percent of species in family Suidae (pig relatives) were classi-fied as threatened (McGowan, 2010).

4.2.3 Forest genetic resources

The total number of extant tree species in the world remains uncertain. However, it is estimated to be about 60 000 (Beech et al., 2017). The country reports submitted for The State of the World’s Forest Genetic Resources (SoW-FGR) list nearly 8 000 species of trees, scrubs, palms and bamboo, of which about 2 400 are actively managed for the products and/or services they supply (FAO, 2014a).

Globally, more than 700 species are now included in tree-breeding programmes.

The status and trends of forest genetic resources are monitored at ecosystem, species and intra-specific levels. However, these efforts are ham-pered by many methodological and other con-straints. Most countries face difficulties in assess-ing their primary forest area. Forest degradation, forest restoration and species composition are also difficult to monitor precisely. Monitoring of the risk status of tree species is currently not compre-hensive globally, although a number of countries are able to monitor the status of all their tree species. The Global Tree Assessment,¹⁵ an initiative led by Botanic Gardens Conservation International and the IUCN/Species Survival Commission Global Tree Specialist Group, aims to provide conserva-tion assessments for all the world’s tree species by 2020 (Newton et al., 2015a).

Globally, forest genetic resources are being threatened and eroded by conversion of forests to agriculture, unsustainable harvesting of trees for wood and non-wood products, grazing and browsing, climate change, forest fires and inva-sive species (FAO, 2014a). In many parts of the world, vast areas of land once covered by forests have been converted to other land uses, with

15 https://www.bgci.org/plant-conservation/globaltreeassessment/

much of this change having occurred during the twentieth century. Forests still cover 30.6 percent of the world’s land area and, while global forest area, and – while global forest area continues to shrink – the rate of annual net loss of forests has decreased significantly over recent decades (FAO, 2016g) (see Section 4.5.5 for further information).

There is no systematic global monitoring system in place for intraspecific diversity in tree species.

The SoW-FGR provides an overview of the state of knowledge in this regard. Schemes for genetic monitoring of forest trees have been proposed at global (Namkoong et al., 1996, 2002) and regional levels (e.g. Aravanopoulos et al., 2015). However, they have not yet been implemented, and only a very few countries have tested such schemes in practice (e.g. Konnert et al., 2011). Loss of intraspecific diversity in economically important tree species has been a major concern in forest management for decades. Forest management practices can have genetic impacts on tree pop-ulations. However, they need to be assessed on a case-by-case basis. The extent of the impact depends on the management system and the stand structure, as well as on the demography, biological characteristics and ecology of the species (Wickneswari et al., 2014). In temperate forests, for example, silvicultural interventions, such as the thinning of stands, usually have limited genetic consequences (Lefèvre, 2004), and many silvicultural systems maintain genetic diversity in tree populations rather well (Geburek and Müller, 2005). However, if forest management practices change evolutionary processes within tree popu-lations, this can have a more profound impact on the genetic diversity of subsequent generations of trees (Lefèvre et al., 2014).

4.2.4 Aquatic genetic resources for food and agriculture

Globally, there are more than 31 000 species of finfish, 52 000 species of aquatic molluscs, 64 000 species of aquatic crustaceans and 14 000 species of aquatic plants (Balian et al., 2007;

Chambers et al., 2008; Lévêque et al., 2008; WoRMS, 2018). In 2016, global capture fisheries harvested

over 1 800 species, including finfish, crustaceans, molluscs, echinoderms, coelenterates and aquatic plants (FAO, forthcoming). Within these thousands of species there are numerous genetically distinct stocks and phenotypes.

Fisheries and aquaculture data submitted to FAO by its member countries provide valuable information on various aspects of aquatic BFA.

However, information is not always reported at the species level. This is especially problematic for inland fisheries, where over half of all production is not designated by species (Bartley et al., 2015).

In the case of aquaculture, available data suggest that more species are now being farmed than ever before, especially as more marine fishes are being bred in captivity (Duarte, Marbà and Holmer, 2007;

FAO, 2016h). Country reports prepared for The State of the World’s Aquatic Genetic Resources for Food and Agriculture (FAO, forthcoming) report the farming of 694 species and other tax-onomic groups. As of 2016, FAO had recorded data on about 598 species used in aquaculture:

369 finfish species (including hybrids); 104 mollusc species; 64 crustacean species; 7 amphibian and reptile species (excluding alligators, caimans or crocodiles); 9 other aquatic invertebrate species;

and 40 species of aquatic algae (FAO, 2018a).

The level of monitoring of species and popula-tions harvested in marine and inland fisheries and raised in aquaculture varies substantially across these subsectors and across the world. Monitoring of diversity at intraspecies level is relatively undevel-oped in the aquatic sector as compared to the terres-trial livestock and crop sectors (FAO, forthcoming).

The state of the world’s marine fisheries is assessed by FAO through the analysis of over 400 stocks of fish. Species targeted by marine fish-eries are classified according to whether they are overfished (fished at biologically unsustainable levels), maximally sustainably fished (fished at bio-logically sustainable levels) or underfished. As of 2015, 33.1 percent of fish stocks were estimated to be overfished, 59.9 percent to be maximally sus-tainably fished and 7.0 percent to be underfished (FAO, 2018a). The share of fish stocks within bio-logically sustainable levels (maximally sustainably

fished or underfished) declined from 90 percent in 1974 to 66.9 percent in 2015 (ibid.). FAO does not provide an equivalent analysis for inland fisheries.

The state of inland capture-fishery resources is more difficult to monitor for a number of reasons, including the diffuse character of the sector, the large number of people involved, the seasonal and subsistence nature of many small-scale inland fisheries, the fact that much of the catch is con-sumed locally or traded informally, and the fact that populations can be greatly affected by activ-ities other than fishing, including stocking from aquaculture and diversion of water for other uses such as agriculture and hydroelectric development (FAO, 2012b). While there is no dedicated FAO pro-gramme addressing the state of inland fisheries, the Thirty-second Session of the FAO Committee on Fisheries recommended “the development of an effective methodology to monitor and assess the status of inland fisheries, to underpin their value, to give them appropriate recognition and to support their management … [and] requested that FAO develop this assessment methodology, including broader ecosystem considerations that impact inland fisheries” (FAO, 2016h).

Top-level carnivores are reported to have declined in many marine and inland fisheries (Pauly et al., 1998). This is referred to as “fishing down the food web” and can indicate overfishing (ibid.). In such cases, the productivity of a fishery remains high, especially in inland waters, as lower trophic-level species increase in abundance in the absence of larger predators; however, the value of the fish drops as the large, more-valuable species disappear (Welcomme, 1999).

The status of many aquatic species is assessed by conservation and trade organizations. The IUCN Red List¹⁶ classifies over 1 300 marine species (including plants, fish, molluscs, crustaceans and other invertebrates) and over 5 200 wetland species as Endangered, Threatened or Vulnerable.¹⁷ Among freshwater fish (not the wider range of biodiversity mentioned above), out of 5 785 species that had

16 http://www.iucnredlist.org/

17 The IUCN Red List of Threatened Species. Version 2017-3.

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been assessed for The IUCN Red List at the end of 2011, 60 were considered extinct, 8 Extinct, 8 Extinct in the Wild and 1 679 (29.3 percent) threatened (Carrizo, Smith and Darwall, 2013). If it is assumed that the 1 062 species classified as data deficient are threatened in the same proportion as species for which data are available, the proportion of threat-ened species would amount to 36.1 percent of the total (ibid.). However, not all the fish species assessed by IUCN are used for food and agriculture. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)¹⁸ maintains information on the status of aquatic species that are traded internationally. Several species used in fisheries and aquaculture (e.g. sturgeons, tunas and sharks) are on the CITES Appendices.¹⁹