In situ conservation

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Conservation

Wild wheat (Triticum araraticum) in the Erebuni State Reserve in Armenia, a reserve that protects wild relatives of a crop.

Cannabis conservation·Grow-out priorities·Populations

Threat Categories

Extinction

Genetic Threats

Genetic erosion·Genetic contamination·Introgression·Gene flow·Hybridisation·Population bottleneck·Genetic drift·Inbreeding depression

Habitat & Environmental Threats

Habitat loss

Eradication Tracking & Analysis

Eradication·Herbicide spraying of cannabis·Herbicide spraying in Mexico·Herbicide spraying in the United States·Herbicide spraying in Colombia·Herbicide spraying in Belize·Herbicide spraying in South Africa·US eradication abroad·Yukthiya·Cannabis eradication in Kirivong·Cannabis eradication in Fiji·Campaigns by country

International Enforcement

Cannabis prohibition·US eradication abroad·INCB

Legal & Policy

Farmers' rights·Access and benefit-sharing·Intellectual property·Single Convention on Narcotic Drugs·1988 Convention·Cannabis legalisation movement

Population Assessment

Minimum viable population·Population viability analysis·Effective population size

Conservation Monitoring

Population monitoring·Genetic monitoring

Conservation Methods - Ex Situ

Ex situ conservation·Gene bank·Cryopreservation·In vitro conservation·Core collection·Seed storage

Conservation Methods - In Situ

In situ conservation·On-farm conservation·Genetic reserve·Community seed bank·Feral and ruderal populations

Genetic Conservation

Germplasm·Genetic resources·Crop wild relative·Conservation genetics

Sampling & Collection

Germplasm collecting·Germplasm sampling

Preservation Strategies

Conservation prioritisation·Complementary conservation

Recovery & Restoration

Reintroduction·Genetic rescue

Conservation Science

Landrace conservation

Portal·Category

In situ conservation is the conservation of populations in the places where they grow: for a wild plant its natural surroundings, for a cultivated plant the surroundings where it developed its distinctive properties. For plant genetic resources it takes two forms, the genetic reserve for wild species and on-farm conservation for landraces.^: 16–17 A population kept this way goes on evolving, which a stored sample does not.

John McPartland and Ernest Small judged in situ conservation "much preferable" for crop plants and their wild relatives, then called seed banks "an immediate priority" for Cannabis, given the state of its wild populations in Asia. The reviews of cannabis genetic resources by Welling and colleagues (2016), Clarke and Merlin (2016) and McPartland and Small describe no reserve or on-farm project set up to conserve the plant. Farmers who save seed keep local populations going without any such project. In the cases reported, local people use the plant inside protected areas and police and rangers destroy it.

What the term covers

The Convention on Biological Diversity of 1992 defines the term as "the conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings and, in the case of domesticated or cultivated species, in the surroundings where they have developed their distinctive properties".^{: art. 2} Its article 8 asks parties to set up systems of protected areas, to promote the recovery of threatened species and, subject to national law, to "respect, preserve and maintain" the knowledge and practices of indigenous and local communities that bear on conservation.^{: art. 8} The International Treaty on Plant Genetic Resources for Food and Agriculture of 2001 names both settings: the efforts of farmers and local communities "to manage and conserve on-farm" and wild crop relatives "including in protected areas".^{: art. 5.1}

Maxted, Ford-Lloyd and Hawkes set out a working method for plants in Plant Genetic Conservation: The In Situ Approach (1997), with chapters on choosing target taxa, surveying them, designing reserves, managing and monitoring them and conserving crops locally. In their usage the term means locating populations, designating sites, managing them and monitoring the plants.^: 16–17 A genetic reserve is an area designated for active, long-term conservation of genetic diversity in wild populations. On-farm conservation is the management of landrace diversity by farmers within traditional farming systems.^: 18

Active conservation monitors and manages a population over the long term. A taxon that occurs in a protected area with no formal plan is passively conserved, and its decline may pass unnoticed by the area's manager. A farmer who keeps a landrace outside any project is in the same position.

Populations under selection

Mauricio Bellon and colleagues described collections in gene banks as "frozen snapshots" of each population at the time of collecting. The alleles of a stored sample decline through genetic drift if regrowing is badly done. Populations left in the field stay exposed to changing pressures, some natural and some from farmers. The case for keeping them there has two parts: continued selection should generate and favour new variation, and rare alleles of future value should persist.

Landraces of pearl millet collected at the same places in the Sahel 27 years apart, through a period of recurrent drought, differed when grown together: the later plants were smaller, with shorter life cycles and more of a flowering gene. Mixed wheat populations sown at contrasting sites in France and left to evolve for more than 26 years changed in height and earliness and diverged in flowering time.

Bellon and colleagues judged this evidence fragmented, though strong enough in circumstantial terms to support the evolutionary case. They counted 59 types of intervention in support of on-farm conservation. They found little evidence that the interventions did more than farmers were already doing, and none yet of effects on genetic diversity. Maxted and colleagues reported wide agreement that in situ conservation should be the primary strategy, with storage as a backup.^: 17 For Bellon and colleagues neither is sufficient alone, and the two are complementary. Stored seed can restock a population that has disappeared and gives a past sample to set beside the living one.

Reserves and protected areas

The Tirthan in its gorge in the Great Himalayan National Park, where hemp is recorded on survey transects and in the villagers' use.

The Convention defines a protected area as "a geographically defined area which is designated or regulated and managed to achieve specific conservation objectives".^{: art. 2} Most protected areas are likely to hold some crop wild relatives, but they were probably established for landscapes, habitats or fauna. Few reserves have been set up for the purpose. They include reserves for wheat relatives in Israel and at Erebuni near Yerevan in Armenia, and for the teosinte Zea diploperennis in south-west Mexico.^: 20 Wild relatives in other protected areas are largely conserved passively and remain open to invasive species, habitat degradation and management aimed at other ends.

In the cases reported, local people use Cannabis inside protected areas and police and rangers remove it. In the Great Himalayan National Park in India, C. sativa, locally bhang, grows at 2,100 to 2,700 m and was among the plants "commercially exploited before creation" of the park.^{: 187, 201, 211–213} The park's management plan for 2010 to 2020 calls hemp "a local fiber being used by the villagers for their local requirements". It proposes training in hemp handicrafts and awareness programmes to "discourage its trafficking in narcotics".^{: Part 1, pp. 74–75; Part 2, p. 105}

Police in Sri Lanka reported destroying 150,000 plants inside Yala National Park in February 2021, and gendarmes in Madagascar cleared a 30-hectare plantation in the protected area of Tsaratanana in June 2023, seizing 30 kg of seed with the plants. The director of Virunga National Park said in 2011 that its rangers were planning operations against the cannabis trade there. In 2017 people from a Bambuti village, whose community had been evicted when the park was made, were growing cannabis in secret in its forests. They said their ancestors had grown it. They harvested plants and seed from wild stands when their village stock ran low.

Landraces on farms

Seed kept in a bottle by a farmer at Thanalmalwila in Uva Province, Sri Lanka.

Farmers who hold back part of each harvest for sowing keep a landrace going with no outside programme, a process Stephen Brush called de facto conservation. It lasts while the crop serves them and weakens as bred varieties, formal seed supply, new markets and migration offer other courses.

Clarke and Merlin held that indigenous farmers who maintain localised landraces preserve genetic diversity, because such populations reproduce sexually and go on evolving under selection. In the Tai'an district of Shandong, Clarke reported in 1995, "Seeds of the local landrace are reproduced each year from remnant seed saved by the farmer", with no intentional selection except possibly for large seed and no imports of improved seed from elsewhere in China. In the Rif Mountains, in Pierre-Arnaud Chouvy's account, Berber tribes made the conservation of the kif landrace possible despite the drug laws and state repression.

Clarke and Merlin also judged that the majority of traditional fibre, seed and drug landraces are no longer grown and that many of those remaining have been diluted by crossing with introduced cultivars, which they called the "degradation of in situ conservation". Chouvy warned against treating a landrace in fixed terms, or "musealized" through strict conservation, since landraces go on changing. He argued that an appellation of origin, by protecting the agro-ecosystem behind a product, is the only form of intellectual property suited to landrace conservation, and that the illegality of the product makes such protection problematic for now.

Morocco's law of 2021 on licit uses requires growers to use seed certified by the national cannabis agency, ANRAC.^: 1173 In 2024 the agency allowed the local variety, called Beldia in the Moroccan press. The first plot, of about 30 hectares on the four slopes of Jbel Tidirhine, was to supply pharmaceutical and cosmetic uses. The president of the cooperative behind it said that INRA Maroc had studied eight local ecotypes there and that a selection trial aimed to improve the variety and help it resist the spread of modified varieties. By August 2024 the agency had allowed 1,634 quintals of the seed for 106 cooperatives of 1,816 farmers on 1,916 hectares. One cooperative's president described the scheme as a way to support growers unable to buy imported varieties. Neither report gives a plan for monitoring the population's diversity.

Wild and feral stands

Feral hemp in a roadside ditch in Buffalo County, Nebraska.

McPartland and Small named two wild-growing relatives of the drug-type domesticates, C. sativa subsp. indica var. himalayensis in South Asia and var. asperrima in Central Asia, and described them and the domesticates as "critically endangered reservoirs of germplasm". Whether these or any other plants are wild in the strict sense is disputed (see Feral and ruderal Cannabis). Wild-growing populations are hard to sample because of the plant's legal status and economic importance.

Police and drug agencies have treated such stands as targets for eradication. In 2015 the United Nations Office on Drugs and Crime reported that 550 hectares of wild cannabis grew in the Issyk-Kul province of Kyrgyzstan and supported an operation there that destroyed more than 15 tons in a day. The United States Drug Enforcement Administration claimed to have destroyed more than 1.9 billion feral or wild plants between 1998 and 2006, on Canavan and colleagues' sum of its annual figures.

Work on these populations as a genetic resource has taken samples away from them. Aina and colleagues collected seed and tissue from 1,821 feral plants in 91 populations across 12 American states in 2022 and 2023 for the federal hemp repository. Ford and colleagues, who called the Midwestern populations "a top priority for conservation efforts", used habitat models to pick areas for further collecting. Researchers at the Vavilov Institute sampled 128 hemp populations growing in four federal districts of Russia between 2008 and 2011. Canavan and colleagues regard feral cannabis as a weed and possible invader and recommend monitoring for volunteer plants so that these can be removed early.

Treaty duties

The United Nations Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988 requires each party to take measures "to eradicate plants containing narcotic or psychotropic substances, such as opium poppy, coca bush and cannabis plants, cultivated illicitly in its territory". Those measures must respect fundamental human rights and "take due account of traditional licit uses, where there is historic evidence of such use, as well as the protection of the environment".^{: art. 14(2)} The Single Convention on Narcotic Drugs does not apply to growing cannabis "exclusively for industrial purposes (fibre and seed) or horticultural purposes".^{: art. 28(2)} Neither article mentions the conservation of genetic resources. Welling and colleagues held that the conventions contributed to the erosion of publicly accessible stored collections.

What the sources do not establish

That these reviews name no programme does not show that no local effort exists. The cases in Bellon and colleagues' review come from other crops, Cannabis appears in Maxted's resource book only in a list of European crop databases, and Welling and colleagues write about stored collections.

None of these sources measures a cannabis population on a farm or in a reserve over time, in the way the pearl millet landraces were compared. Nor do Clarke and Merlin give a count behind their judgement that most landraces have gone. Whether a population keeps its variation when seed is saved depends in part on how many plants breed (effective population size).

See also

• Complementary conservation
• Crop wild relative
• Eradication
• Ex situ conservation
• Feral and ruderal Cannabis
• Gene bank
• Genetic contamination
• Genetic reserve
• Germplasm
• Landrace Cannabis
• Landrace conservation
• On-farm conservation