1. Trees outside of forests Devising options for conservation of two tree species outside of forests David Boshier

2. What are the impacts of human interventions on trees? What are the genetic impacts of human interventions on trees?

3. impacts of human interventions on trees? fragmentation, afforestation, silviculture, deforestation, agriculture, shifting cultivation, premature death, clear fell genetic impacts of human interventions on trees? hybridisation, inbreeding depression, dysgenic selection, loss of genetic diversity, species loss, increase variance between populations, genetic loss/erosion Examples from other classes

4. Genetic impacts of human interventions on trees Humans impact forests in a variety of ways, eg conversion of forest to agriculture & other uses forest fragmentation logging, harvesting of different types domestication/breeding Need to consider influence of interventions on functionality of tree populations & relevance to conservation

5. Genetic impacts of human interventions on trees All interventions influence genetic diversity of trees to greater or lesser extent In many circumstances impacts on genetic diversity may not be a priority Foresters/conservation managers need to be able to identify - – how patterns of genetic variation are altered – under what sort of circumstances genetic diversity and its loss may become limiting

6. Where & how should we conserve? In situ - reserve system of undisturbed, protected areas within natural distribution (ecosystem based) Ex situ - artificial maintenance of populations outside natural distribution (species based) In situ - Ex situ 6

8. Impacts of human disturbance often superimposed on habitat heterogeneity may lose species and populations adapted to lowlands/good soils not random

9. Conservation of biodiversity in situ: trees as a paradigm ideal reserve model emphasis: large, continuous, protected areas limitations: location, size, security, biology: –movement of animals –extensive distribution of many species –gene flow between populations –upland, non agricultural areas essential but not sufficient

10. Where should we conserve? In situ - reserve system of undisturbed, protected areas within natural distribution (ecosystem based) Ex situ - artificial maintenance of populations outside natural distribution (species based) In situ - Ex situ 10

11. Conservation of biodiversity ex situ: methods and limitations seed banks - problems of regeneration plantations - changes in gene frequencies, few populations botanical gardens - deficiencies for gene pool conservation 11 © RBG Kew

12. a large number of individuals of many species have long ago ceased being ecologically (and evolutionarily) reproductive; they flower but set no seed, or if they set seed, the seedlings never lead to recruitment of adults. 12 © DH Boshier These are the living dead Janzen 1986

14. Conservation of species and genotypes Conservation paradigms – in situ, ex situ, through use on farms – circa situm Fragmentation – gene flow patterns and maintenance of viable populations Reproductive materials: source and collection Issues of concern – conservation of tree genetic resource outside of forests

15. Theory direct impacts decrease pop. size increase spatial isolation decrease densities change local environment genetic processes genetic drift gene flow mating - inbreeding selection

16. Fragmentation x y z x y z x y z x y z zz z yy z z y yy z zzz zzzxx yyy x y x Fragmentation yzxy x yz y xz zx yx x y z x y z x y z x y z x y x A: Low genetic structure B: High genetic structure Low genetic differentiation (Gst) High genetic differentiation (Gst)

17. Extinction x y z x y z x y z x y z Extinction x y B: Gene flow reduces loss of genetic diversity Reduced genetic differentiation (Gst) Increased genetic differentiation (Gst) A: Drift and extinction: loss of genetic diversity x y x y z x z x y Drift – no gene flow x y z x y z x y z x y z x y x z z x y y x y z Drift gene flow

18. B: fragmentation Low genetic differentiation (Gst) High genetic differentiation (Gst) A: fragmentation x z x y x y x z z x z y x yzx y x y z y x z zx y x x y z x y z x y z x y z yzx y x y z y x z zx y x x y z x y z x y z x y z x y z x x y z x y z x y z z y x x y z x x y z x y z x y z z y x with drift among isolates with gene flow via ‘isolated’ trees

19. Range of land-use systems may be important for long term genetic viability of some tree species through –conservation of particular genotypes not found in reserves –facilitation of gene flow between existing reserves –maintenance of MVPs (Minimum Viable Populations) –intermediaries & alternate hosts for pollinators & seed dispersers Broad vision of corridors - mosaic of land-uses that promote connectivity & conservation of biodiversity more generally

20. Isolated trees – can we collect seed?

21. Altered mating patterns in fragments Predictions: increased inbreeding greater pollen dispersal fewer sires Isolated tree Continuous forest inbreeding dispersal sires

22. Can valuable tree genetic resources persist outside of forests and if so what measures need to be taken to ensure they persist?

23. Swietenia humilis – IUCN listed as vulnerable, also on CITES appendix II monoecious flowers, self-incompatible, bee pollinated, wind dispersed

24. trees sampled at Punta Ratón, Honduras Swietenia humilis White, Boshier & Powell, 2002

25. Pollen flow into fragments Swietenia humilis FragmentFragment % pollen from “size”outside Las Tablas*97 36.0 El Jicaríto44 47.0 Cerro El Jiote22 38.3 Tablas Plains 8 68.4 Tree 501** 1100.0 * part of continuous forest, surrounded by unsampled trees ** an “isolated” tree White, Boshier & Powell, 2002

26. Frequency of pollen flow to S. humilis trees in Cerro Jiote fragment and to an “isolated” tree, Honduras 0 0.4 0.8 >1.50.9-1.20.3-0.6 Distance, km Pollen donors White, Boshier & Powell, 2002 0 0.4 0.8 4.53.3-3.60.9-1.22.1-2.4 Distance, km Pollen donors ‘Isolated’ tree C. Jiote

27. >20 trees selfed - no seed

28. Pachira quinata Central + South America Deciduous tree Hermaphrodite flowers Self-incompatible Bat (& moth) pollinated Seed + ‘kapok’ wind dispersed

29. Costa Rica: Forest vs Pasture Stewart PropertyLomas Barbudal Reserve

30. Pasture Forest

31. Results: Forest vs Pasture Site Outcrossing rate (SE) Correlation of tm (SE) Number of sires Dispersal distance Forest 0.926 (0.021) 0.117 (0.045)3.3 - 4.148 metres

32. Site Outcrossing rate (SE) Correlation of tm (SE) Number of sires Dispersal distance Forest 0.926 (0.021) 0.117 (0.045)3.3 - 4.148 metres Pasture 0.828 (0.085) 0.636 (0.148)2.9 - 4.4158 metres Lower outcrossing & greater dispersal but not fewer sires in the pasture Results: Forest vs Pasture

33. Site Outcrossing rate (SE) Correlation of tm (SE) Number of sires Dispersal distance Forest 0.926 (0.021) 0.117 (0.045)3.3 - 4.148 metres Fuchs Forest 0.915 (0.043)1.8 - 2.6 Pasture 0.828 (0.085) 0.636 (0.148)2.9 - 4.4158 metres Fuchs Pasture 0.777 (0.114)1.2 - 1.6 Fuchs et al 2003 suggest isolated (>500m) pasture trees receive less outcrossed pollen Results: Forest vs Pasture

34. Costa Rica: Pasture Predict that selfing will increase with isolation But it doesn’t! 82% 71% 51% 29% 20% Isolated by 350m

35. Self-incompatibility system Reduced germination of self pollen –Slower growth rate of self pollen Ability to self varies among trees –50% non-selfers –12.5% selfers Pollen reaching ovarySelfCross 48 hours15%56% 72 hours64%90% 120 hours89%90%

36. WCMC World List of Threatened Trees (IUCN Red List categories of threat) http://www.wcmc.org.uk/trees/Background/intro.htm http://www.wcmc.org.uk/trees/Background/intro.htm 9% of world's tree flora globally threatened with extinction accuracy of assessment? IUCNthis study S. humilis - vulnerable? P. quinata - not listed?

37. Your task Derive an action plan to ensure effective conservation and use of both species outside of forests