Alison Shapcott

The OJIP fast fluorescence rise characterizes Graptophyllum species and their stress responses

Causes for rarity in plants are poorly understood. Graptophyllum reticulatum is an endangered endemic species, and it has three close relatives with different conservation status: the vulnerable G. ilicifolium, the rare G. excelsum, and the common G. spinigerum. Applied to the chlorophyll a fluorescence transient of leaves, the JIP test provides a Performance Index (PI) which quantifies the main steps in photosystem II (PSII) photochemistry including light energy absorption, excitation energy trapping, and conversion of excitation energy into electron flow. The PI is calculated from three components which depend on the reaction center density, the trapping efficiency, and the electron transport efficiency. PI was measured in the natural habitats of the four species and under artificially imposed environmental stresses in the glasshouse to determine whether conservation status was related to stress resilience. The results showed that soil type is unlikely to restrict the endangered G. reticulatum, vulnerable G. ilicifolium, or rare G. excelsum because PI was similar in plants grown in diverse soils in the glasshouse. Photoinhibition is likely to restrict the endangered G. reticulatum to shade habitats because PI was significantly reduced when plants were exposed to more than 15% ambient light in controlled experiments. Water availability may determine the location and distribution of the vulnerable G. ilicifolium and common G. spinigerum because PI was reduced more than 60% when plants were exposed to water stress. While the characteristics of their natural habitats correspond to and explain the physiological responses, there was no obvious relationship between conservation status and environmental resilience. PI can be used to monitor vigor and health of populations of plants in the natural habitat. In cultivation experiments PI responds to key environmental variables that affect the distribution of species with conservation significance.

Genetic and Ecological Variation in Atherosperma moschatum and the Implications for Conservation of its Biodiversity

Population genetics and ecology of Atherosperma moschatum Labill. (sassafras), a major canopy tree of Australian temperate rainforests, were examined and used to identify priorities and strategies for conservation of its genetic diversity. The genetic diversity among populations was fairly low, but higher than average for long-lived late successional or wind dispersed species (Hamrick and Godt 1989). Genetic distances between populations were correlated with geographic distances and climatic differences. The major genetic differentiation was between the mainland populations and those in Tasmania, with the New South Wales populations being quite genetically distinct. Most genetic variation was found within populations, however, most populations were inbred. This is likely to be due to selfing and spatial genetic substructure resulting from vegetative spread and local dispersal. There was evidence of regeneration in all populations, however no consistent regeneration patterns emerged. Population density was inexplicably correlated with genetic distance. There was as much diversity in all variables (ecological and genetic) measured in small isolated populations as there was in stands within larger assemblages; therefore, population size does not appear to be a major factor affecting viability. Genetic variation was spread throughout the distribution of A. moschatum. Therefore, populations from throughout its range would need to be conserved to retain the genetic diversity within this species.

Low genetic diversity and recovery implications of the vulnerable Bankoualé Palm Livistona carinensis (Arecaceae), from North-eastern Africa and the Southern Arabian Peninsula

The Bankoualé Palm, Livistona carinensis is the only known species of Livistona occurring in Africa and is currently classified as vulnerable (IUCN 2004). This extreme outlier species of the genus is restricted to Yemen, Somalia and Djibouti, where all populations are in rapid decline. In Djibouti the palm is confined to three valley systems within the upland plateau of the Goda Massif. This study used microsatellite markers to investigate the genetic diversity and relationships within the species. At the species level L. carinensis contained very low genetic diversity. Most variation was due to the variation between the samples from Yemen and Somalia compared with those in Djibouti. The Djibouti populations were almost monomorphic across the nine loci tested. Interestingly, and despite the small sample sizes, the individuals from botanic gardens collections of the Yemen and Somalia populations were more genetically diverse than the Djibouti populations. This study indicates that the populations in Yemen and Somalia are highly significant for the conservation of the species genetic diversity. Given the lack of genetic diversity both within and among L. carinensis populations in Djibouti, plants could be cultivated for in-situ population enhancement from any seed that is available from within Djibouti with no significant genetic impacts of provenance mismatch. Clearly the populations from Djibouti, Somalia and Yemen are different genetic provenances raising some issues for the conservation and recovery of L. carinensis.

The genetics of Ptychosperma bleeseri, a rare palm from the Northern Territory, Australia

Ptychosperma bleeseri is known from only eight small monsoon rainforest patches located in the vicinity of Darwin, Australia. One population consists of only one adult plant and only one patch contains a population of more than 50 adult plants. A survey of the genetic diversity within the species was undertaken using isozyme analysis. Almost no genetic variation was recorded. Of the 223 wild collected samples tested, only four individuals varied at a single locus out of the 10 loci analyzed. The lack of diversity among populations suggests that the existing populations are derived from a common, genetically depauperate, source which has acted as a founder population. P. bleeseri was compared with the other Ptychosperma species which occur naturally in Australia (P. macarthurii and P. elegans). Each of these species was found to differ consistently at several enzyme loci thus indicating that P. bleeseri does not simply represent an outlying population of either of these two species. Cultivated specimens of P. bleeseri were shown to have hybridized with other cultivated Ptychosperma species when grown together. This presents a problem for ex-situ conservation. Since palms are particularly favoured by Darwin residents in their gardens and public places, the location of urban development in close proximity to wild populations of P. bleeseri has the potential to introduce other Ptychosperma species into the wild populations. This could have serious effects on the genetic integrity of the species.

Demographic structure, genetic diversity and habitat distribution of the endangered, Australian rainforest tree Macadamia jansenii help facilitate an introduction program

Macadamia jansenii is endemic to south-east Queensland, Australia, and is currently known from a single population 180 km north of the nearest wild population of its congener, the edible Macadamia integrifolia. A recently developed Macadamia recovery plan identified that this population was under significant threat and recommended a reintroduction program to safeguard against chance extinction of the single wild population. This study undertook demographic population census surveys, genetic analysis, habitat analysis and niche modelling to determine the potential long-term viability for the species, and to guide search and reintroduction programs. We expanded the known population size of the species to ~60 individuals (1 m and taller) spread over a 900-m distance along a single creek clumped into three subpopulations. There was moderate genetic diversity in the species and the subpopulations showed little genetic differentiation. We developed a potential habitat model combining abiotic variables and vegetation associations, and mapped areas of potentially suitable habitat for M. jansenii within its local area. These maps are being used to target searches for other populations and to guide the location of introduction populations.

Mapping Biodiversity and Setting Conservation Priorities for SE Queensland’s Rainforests Using DNA Barcoding

Australian rainforests have been fragmented due to past climatic changes and more recently landscape change as a result of clearing for agriculture and urban spread. The subtropical rainforests of South Eastern Queensland are significantly more fragmented than the tropical World Heritage listed northern rainforests and are subject to much greater human population pressures. The Australian rainforest flora is relatively taxonomically rich at the family level, but less so at the species level. Current methods to assess biodiversity based on species numbers fail to adequately capture this richness at higher taxonomic levels. We developed a DNA barcode library for the SE Queensland rainforest flora to support a methodology for biodiversity assessment that incorporates both taxonomic diversity and phylogenetic relationships. We placed our SE Queensland phylogeny based on a three marker DNA barcode within a larger international rainforest barcode library and used this to calculate phylogenetic diversity (PD). We compared phylo- diversity measures, species composition and richness and ecosystem diversity of the SE Queensland rainforest estate to identify which bio subregions contain the greatest rainforest biodiversity, subregion relationships and their level of protection. We identified areas of highest conservation priority. Diversity was not correlated with rainforest area in SE Queensland subregions but PD was correlated with both the percent of the subregion occupied by rainforest and the diversity of regional ecosystems (RE) present. The patterns of species diversity and phylogenetic diversity suggest a strong influence of historical biogeography. Some subregions contain significantly more PD than expected by chance, consistent with the concept of refugia, while others were significantly phylogenetically clustered, consistent with recent range expansions.

Genetic diversity and population genetic structure in three threatened Ocotea species (Lauraceae) from Brazil’s Atlantic Rainforest and implications for their conservation

The Atlantic Rainforest in Brazil is currently comprised of small fragments due to the history of conversion and degradation in the last five centuries. The rainforest trees, Ocotea catharinensis, O. odorifera and O. porosa have been heavily harvested because of the high economic value of their timber and essential oils. Their respective habitats have undergone substantial reduction in area due to continuing anthropogenic pressures. As a consequence, these species have suffered large declines in population size and are now considered to be potentially vulnerable to extinction. This study investigated the patterns and levels of genetic diversity and inbreeding of these species using eight microsatellite markers in order to define priority populations for conservation management actions focusing on population enhancement and ex situ germplasm collections. High genetic diversity was found for each of the species with moderate genetic differentiation among populations. Most populations displayed significant inbreeding and isolation by distance. The results provide important information to choose priority populations for both in situ and ex situ conservation measures.

Contrasting patterns of genetic diversity between two endangered palms with overlapping distributions, Voanioala gerardii (Arecoideae) and Lemurophoenix halleuxii (Arecoideae), from North-east Madagascar

Madagascar has a high diversity of endemic palm species and the Masoala Peninsula is a hotspot for their diversity. Several species are critically endangered and their populations known to be in decline due to a combination of land clearance, destructive harvesting for heart of palm and potentially unsustainable commercial seed collection. The critically endangered Voanioala gerardii and the endangered Lemurophoenix halleuxii are two palm species from monospecific genera endemic to Madagascar that overlap in their distribution within this region. This project undertook field surveys of all known populations of these two species to document their population sizes and locations. We modelled their area of potentially suitable habitat within the region and undertook genetic analysis to investigate genetic diversity and relatedness among populations of each species. The study found overlapping but contrasting patterns of potential habitat. It also found contrasting levels and patterns of genetic diversity between the two species that were not consistent with the modelled habitat distributions. We found that Voanioala gerardii populations are critically small but contain unexpectedly high levels of genetic diversity, which may indicate as yet undiscovered populations remaining. An active program to change methods of seed collection and to involve local villagers and land managers in the conservation of these species would be required to prevent their extinction.

The importance of genetic considerations for planning translocations of the rare coastal heath species Boronia rivularis (Rutaceae) in Queensland.

The Sunshine Coast of Queensland, Australia, is facing increasing pressure from rapid urban expansion. Because of the area’s high biodiversity, developers are facing pressure to translocate rare, endangered, and vulnerable plants to more protected areas. Translocation of turves, comprising sections of soil and intact aboveground vegetation, has been used as a strategy for reintroducing understory species where establishment from seed is difficult. Moving populations spatially can change levels and direction of gene flow. In what appears to be one of the largest reported translocations of a rare species, this study uses allozymes, which are variant forms of enzymes, to investigate the genetics of a population of the rare heath species Boronia rivularis, which is to be translocated to compensate for an urban development. The population on the development site was found to be significant due to its large size and high genetic diversity and distinctiveness. Diversity and inbreeding levels were not evenly distributed across the development site; inbreeding was highest where density was highest. It was found that retention of a significant portion of the population on the development site reduced the potential loss of connectivity. However, we found that ecological assessments based on density could have led to the loss of the most genetically diverse and least inbred parts of the population.

Population genetics of Philotheca sporadica (Rutaceae) to advise an offset translocation program

Philotheca sporadica (Rutaceae) is a vulnerable species restricted to a small geographic area, with very few populations protected in reserves. Environmental impact surveys identified some populations that will be impacted by gas pipeline construction. This study aimed to determine the genetic diversity of P. sporadica to advise an offset planting program. P. sporadica was found to have high population genetic diversity but all populations were genetically similar except two isolated genetically depauperate populations. Genetic diversity decreased with decreasing population size and increasing population isolation. Impacted populations were significant for the species viability, being among the largest and most genetically diverse, although a high percentage of populations were reproductively active and not inbred. A congeneric species P. difformis ssp. difformis that grows in the nearby vicinity was shown to be genetically distinct but some evidence of hybridisation was found suggesting that offset populations should not be located near known populations of this species to prevent further hybridisation.