Recovery of threatened plant species and their habitats in the biodiversity hotspot of the Southwest Australian Floristic Region

Achieving zero extinction for land plants

Despite the importance of plants for humans and the threats to their future, plant conservation receives far less support compared with vertebrate conservation. Plants are much cheaper and easier to conserve than are animals, but, although there are no technical reasons why any plant species should become extinct, inadequate funding and the shortage of skilled people has created barriers to their conservation. These barriers include the incomplete inventory, the low proportion of species with conservation status assessments, partial online data accessibility, varied data quality, and insufficient investment in both in and ex situ conservation. Machine learning, citizen science (CS), and new technologies could mitigate these problems, but we need to set national and global targets of zero plant extinction to attract greater support.

The role of landscape history in the distribution and conservation of threatened flora in the Southwest Australian Floristic Region

The flora of the Southwest Australian Floristic Region (SWAFR) is characterized by remarkable richness, endemism, spatial turnover and numbers of threatened taxa. Increasingly, evolutionary history is recognized as contributing to SWAFR biogeographical patterns, culminating in the theory of old, climatically buffered, infertile landscapes (OCBILs) [and their counterpoint: young, often disturbed, fertile landscapes (YODFELs)]. For the SWAFR, we: (1) developed a spatially explicit distribution of OCBILs and YODFELs; (2) analysed the spatial distribution of Threatened and Priority (Data Deficient) flora; and (3) tested the hypotheses that Threatened and Priority flora will be most strongly represented in OCBILs and will have small geographical ranges. We found that OCBILs and YODFELs dominated spatially distinct portions of the SWAFR. Threatened and Priority flora were not uniformly or randomly distributed and were more strongly characterized by narrow-range endemics than the non-Threatened flora. The occurrence of Threatened and Priority flora was positively correlated with the age of surface exposure of landscape features and unique geological features of limited extent (if not YODFELs). The concentration of Threatened flora in OCBILs provides the opportunity to improve conservation management through investigations of how plant traits favoured by evolution in OCBILs might increase or decrease the susceptibility of the flora to anthropogenic threats.

Differential exposure and susceptibility to threats based on evolutionary history: how OCBIL theory informs flora conservation

Optimal conservation approaches have been proposed to differ for biota with contrasting evolutionary histories. Natural selection filters the distribution of plant traits over evolutionary time, with the current expression of traits mediating susceptibility to contemporary and often novel threats. We use old, climatically buffered, infertile landscape (OCBIL) theory to compile predictions regarding differences in exposure and susceptibility to key threats between OCBIL and young, often disturbed, fertile landscape (YODFEL) flora. Based on literature and existing data from the Southwest Australian Floristic Region (SWAFR), we evaluate evidence in support of our predictions, finding strong theoretical and empirical support for the proposition that exposure and/or impact of many threats differs between OCBILs and YODFELs. OCBILs have more exposure to land clearance from mining, whereas many YODFELs have greater exposure to land clearance from agriculture, and urban and industrial land uses, and greater overall levels of habitat loss and fragmentation. OCBIL flora are more susceptible to pathogens and extremes of fire interval than YODFEL flora, but conversely may have a greater capacity to persist in smaller populations if small populations featured in the evolutionary history of the species prior to anthropogenic fragmentation, and have substantial resistance to weed invasion. We argue that consideration of evolutionary history has an important role in informing conservation management.

Tree Communities in Three-Year-Old Post-Mining Sites Under Different Forest Restoration Techniques in the Brazilian Amazon

Forest loss and degradation in the Brazilian Amazon due to mining activities has been intense for many years. To reverse this situation, a range of restoration programs for deforested and degraded areas have been created and implemented. The aim of this study was to analyze the tree composition, successional stage, dispersal and pollination syndromes, conservation status of tree species, and proximity to seed sources under different forest restoration techniques (seedling planting, natural regeneration, and assisted natural regeneration or nucleation) implemented in post-mining sites in the Paragominas municipality (Pará, Brazil). Sixty permanent plots with a restoration age of three years were selected for tree sampling. A total of 119 species, 83 genera and 27 botanical families were identified. Sites restored with different techniques significantly differed in tree composition. Seedling planting sites exhibited the highest abundance, species richness, and diversity values. These were dominated less by pioneer species when compared to the natural regeneration and nucleation sites. Entomophilic pollination and zoochory dispersal were highly represented in the three types of restored sites. Abundance and species richness were negatively correlated with distance from plots to seed sources, and they sharply declined in natural regeneration and nucleation plots at >250 m from seed sources. Four threatened species were identified in the restored sites. We conclude that a combination of different restoration strategies at three-year-old post-mining restoration sites in the Brazilian Amazon results in the recovery of considerable levels of local tree diversity.

Quantitative and Qualitative Genetic Studies of Some Acacia Species Grown in Egypt

The objective of the current work is to study the genetic differentiation between Acacia species growing in Egypt as plant genetic resources based on morphological, biochemical, and molecular markers. The 20 replicates of Acacia tree collected from four localities from Egypt were A. tortilis ssp. raddiana and A. farnesiana (Siwa Oasis and Borg El-Arab City), A. stenophylla, A. sclerosperma (Marsa Matroh City), and A. saligna (Abis Station Farm, Alexandria). The results based on the previous markers indicated highly significant differences between Acacia species, confirming the hypothesis of the possibility of using morphological, biochemical, and molecular parameters in species identification. Qualitative characteristics results indicated some similarities and differences that are taxonomically important for comparing taxonomical grouping with morphological data for the genetic description of Acacia species. The activities of antioxidant enzymes have been studied intensively and the results provide strong similarities between the Acacia species (69%), between A. raddiana (Siwa and Borg Al-Arab) and A. saligna, followed by all Acacia species (50%). Finally, the molecular studies showed that a total of 563 amplification fragments, 190 fragments were monomorphic, and 373 fragments were polymorphic. The highest number of amplification fragments (21) was detected with OPB-20 primer, while OPA-20 showed seven amplification fragments; the average number was 13.09. The results indicated that Acacia species exhibit high genetic differentiation, helpful in the future for genetic improvement programs. The novelty of the current study is highlighting the importance of plant genetic resources in Egypt and using different techniques to measure the differentiation between these species.

Conserving plants within and beyond protected areas - still problematic and future uncertain

Against a background of continuing loss of biodiversity, it is argued that for the successful conservation of threatened plant species we need to ensure the more effective integration of the various conservation actions employed, clarify the wording of the CBD targets and provide clearer operational guidance as to how they are to be implemented and their implementation monitored. The role and effectiveness of protected areas in conserving biodiversity and in particular plant species in situ are discussed as are recent proposals for a massive increase of their extent. The need for much greater effort and investment in the conservation or protection of threatened species outside protected areas where most plant diversity occurs is highlighted. The difficulties involved in implementing effective in situ conservation of plant diversity both at an area- and species/population-based level are discussed. The widespread neglect of species recovery for plants is noted and the desirability of making a clearer distinction between species recovery and reintroduction is emphasized. Key messages from a global overview of species recovery are outlined and recommendations made, including the desirability of each country preparing a national species recovery strategy. The projected impacts of global change on protected areas and on species conservation and recovery, and ways of addressing them are discussed.

Recovering threatened plant species and their habitats: The need for integrated action

As an introduction to the Special Issue on the restoration of threatened plant species and their habitats, this editorial shows how the various papers in the issue address the range of in situ interventions involved in species population management and restoration of their habitat, together with examples of case studies implementing these actions. It stresses the need for integrating these various interventions. It highlights the importance of protected areas in providing a degree of protection for threatened species but also the need to complement this with actions at the species level to ensure the effective conservation and long term persistence of these species. It emphasizes that ecological restoration is a complement to, not a substitute for conservation, and that the balance of effort and allocation of resources between them is a key issue.