Limited pollen-mediated dispersal and partial self-incompatibility in the rare ironstone endemic Tetratheca paynterae subsp. paynterae increase the risks associated with habitat loss

Abstract

Patterns of mating and dispersal are key factors affecting the dynamics, viability and evolution of plant populations. Changes in mating system parameters can provide evidence of anthropogenic impacts on populations of rare plants. Tetratheca paynterae subsp. paynterae is a critically endangered perennial shrub confined to a single ironstone range in Western Australia. Mining of the range removed 25% of plants in 2004 and further plants may be removed if the viability of the remaining populations is not compromised. To provide baseline genetic data for monitoring mining impacts, we characterised the mating system and pollen dispersal over two seasons in T. paynterae subsp. paynterae and compared mating system parameters with two other ironstone endemics, T. paynterae subsp. cremnobata and T. aphylla subsp. aphylla that were not impacted by mining. T. paynterae subsp. paynterae was the only taxon showing evidence of inbreeding (t m = 0.89), although hand pollination revealed pre-zygotic self-incompatibility limits the production of seed from self-pollen. In a year of lower fruit set (2005), the estimate of correlated paternity increased from 20 to 35%. Direct estimates of realised pollen dispersal, made by paternity assignment in two small populations where all adult plants were genotyped, revealed a leptokurtic distribution with 30% of pollen dispersed less than 3 m and 90% less than 15 m. Restricted pollen dispersal maintains the strong genetic structuring of the adult populations in succeeding generations. As a consequence of preferential outcrossing, any reduction in effective population size, flowering plant density and/or the abundance and activity of pollinators may impact negatively on population viability through reduced seed set, increased inbreeding and increased correlated paternity.

Genetic drift drives evolution in the bird-pollinated, terrestrial island endemicGrevillea georgeana(Proteaceae)

“…Evidence of restricted pollen movement and strong genetic structure within a BIF population was also observed in Banksia arborea and the Western Australian ironstone endemic Tetratheca paynterae Alford ssp. paynterae (Butcher, McNee & Krauss, ; Butcher, Bradbury & Krauss, ; Nistelberger et al ., ). This pattern has also been observed in populations of species on ‘true island’ systems (Molins, Mayol & Rossello, ).…”

Persistence and stochasticity are key determinants of genetic diversity in plants associated with banded iron formation inselbergs

“…Here we draw on more detailed studies of mating systems and gene flow in the bee‐pollinated Tetratheca paynterae subsp. paynterae (Butcher, Bradbury & Krauss, ) and Acacia woodmaniorum (Millar et al ., ; Millar, Coates & Byrne, ), and the wind‐pollinated Lepidosperma sp. Parker Range and L .…”

Biodiversity hotspots and Ocbil theory

“…150 km southeast of Cape Town Cowling et al (2009a) x A n i m a l s a n d p l a n t s -phylogeographic studies Lexer et al (2013) x EAf, SAf amphibians Poynton (2013) x Oxalis (Oxalidaceae), especially vernal pool species Oberlander et al (2014) x Speciation, extinction -Greater Cape flora Ellis et al (2014) x Topography as a driver of diversification x Salerno et al (2012) x Aulacorhynchus toucanets (Aves, Ramphastidae) Bonaccorso and Guayasamin (2013) x Lizards -Riolama, Arthrosaura, Anadia (Gymnophthalmidae); FrogsOreophrynella (Bufonidae), Anomaloglossus (Aromobatidae), Kok (2013) Plant Soil Tepuihyla tree frogs Salerno et al (2015) x glob Asteraceae, clarifying tepui endemics' position Panero and Funk (2008) x Whole flora Rapini et al (2008) x Vellozia gigantea (Velloziaceae) Martins et al (2012) AtRf Inselberg flora de Paula et al (2015) glob Climatic displacement rate (low-velocity) areas are essential refuges for many small-ranged endemic species x Tetratheca paynterae subsp. paynterae (Elaeocarpaceae) ironstone endemic Butcher et al (2011) x Selected mesic Australian biota Byrne et al (2011b) x Trapdoor spider Moggridgea tingle (Migidae) Cooper et al (2011) x Australian Ground Parrots Pezoporus Murphy et al (2011) x The rare sunset frog (Spicospina flammocaerulea).…”