Trees outside of forests Conservation of tree species diversity in cocoa agroforests in Nigeria David Boshier

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

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

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

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

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

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

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

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

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 © RBG Kew

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. © DH Boshier These are the living dead Janzen 1986

Issues of concern – conservation of tree genetic resource outside of forests Conservation of species and genotypes Conservation paradigms – in situ, ex situ, through use on farms – circa situm

The ‘Living Dead’ or Can valuable tree resources persist outside of forests and if so what measures need to be taken to ensure they persist? an ally for conservation?

Up to 140 species of birds & 40 tree species New tree species discovered in cafetales

Location of Nigeria

Farmer Field Schools

Lovoa trichilioides Milicia excelsa

Lophira alata Vulnerable - IUCN Gossweilerodendron balsamiferum Endangered - IUCN 45 tree species in 21ha agroforests – 6 species with IUCN classification But, 62 species in 0.56 ha of primary forest - 14 species with IUCN classification

Biodiversity and bioquality number of species or the proportion of rare species?

Use the information given here to either: a)derive an action plan to ensure optimum conservation benefits in terms of tree species diversity in the cacao agroforests of Nigeria, or b)present a case for the conservation benefits in terms of tree species diversity in the cacao agroforests of Nigeria