Fragmented but not isolated: Contribution of single trees, small patches and long-distance pollen flow to genetic connectivity for Gomortega keule, an endangered Chilean tree

Lander, Tonya A.; Boshier, David; Harris, Stephen

doi:10.1016/j.biocon.2010.06.028

Cited by 91 publications

(94 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…teretifolius populations that were previously separated by woodland habitat that acted as a barrier to pollen migration between populations are now separated by cleared agricultural land that acts as a contemporary barrier. Reported estimates of pollen immigration into populations of species with rare or naturally patchy populations range from low (4.3-16.5%; Bittencourt and Sebbenn, 2007;Muller et al, 2009;Finger et al, 2011;Llorens et al, 2012) to high (43-77%;OddouMuratorio and Klein, 2008;Lander et al, 2010). Reported changes in immigration levels in recently fragmented species include both increases Bacles and Jump, 2011) and decreases (Robledo-Arnuncio and Gill, 2005;Sebbenn et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Conservation strategies for some rare species have included genetic rescue through artificial crosses in species with low gene flow (Finger et al, 2011) but in others, genetic connectivity may not be a high conservation priority (Lander et al, 2010).…”

Section: Impacts Of Fragmentationmentioning

confidence: 99%

“…Interestingly, Aguilar et al (2008) suggested that, because they have lower genetic diversity with a greater proportion between populations, naturally rare (defined by their narrow geographical range, restricted habitat specificity or small local population sizes), long-lived, selfing or non-outcrossing selfcompatible species may be less susceptible to the reduced gene flow, increased inbreeding and reduced gene diversity associated with fragmentation. However, empirical evidence of the impact of genetic isolation resulting from fragmentation is equivocal (Aguilar et al, 2008;Lander et al, 2010) and there are few studies on contemporary gene migration in rare, self-compatible, mixed-mating species.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Contemporary pollen-mediated gene immigration reflects the historical isolation of a rare, animal-pollinated shrub in a fragmented landscape

Sampson¹,

Byrne

Yates

et al. 2013

Heredity

View full text Add to dashboard Cite

Fragmentation is generally considered to have negative impacts on widespread outbreeders but impacts on gene flow and diversity in patchy, naturally rare, self-compatible plant species remain unclear. We investigated diversity, gene flow and contemporary pollen-mediated gene immigration in the rare, narrowly distributed endemic shrub Calothamnus quadrifidus ssp. teretifolius. This taxon occurs in an internationally recognized biodiversity hotspot subjected to recent human-induced fragmentation and the condition of the remnants ranges from intact to highly degraded. Using microsatellites, we found that inbreeding, historically low gene flow and significant population differentiation have characterized the genetic system of C. quadrifidus ssp. teretifolius. Inbreeding arises from self-pollination, a small amount of biparental inbreeding and significant correlation of outcross paternity but fecundity was high suggesting populations might have purged their lethals. Paternity analyses show that pollinators can move pollen over degraded and intact habitat but populations in both intact and degraded remnants had few pollen parents per seed parent and low pollen immigration. Genetic diversity did not differ significantly between intact and degraded remnants but there were signs of genetic bottlenecks and reduced diversity in some degraded remnants. Overall, our study suggests human-induced fragmentation has not significantly changed the mating system, or pollen immigration to, remnant populations and therefore genetic connectivity need not be the highest conservation priority. Rather, for rare species adapted to higher levels of inbreeding, conservation efforts may be best directed to managing intact habitats and ecosystem processes.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Impacts Of Fragmentationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Contemporary pollen-mediated gene immigration reflects the historical isolation of a rare, animal-pollinated shrub in a fragmented landscape

Sampson¹,

Byrne

Yates

et al. 2013

Heredity

View full text Add to dashboard Cite

show abstract

“…Pasture trees offer habitat for organisms across trophic levels, thereby harbouring biodiversity. They may be also critical in maintaining connectivity across anthropogenically modified landscapes (White et al, 2002;Lander et al, 2010). Remnant Pachira quinata trees in pastures were found to significantly contribute to pollen movement across the landscape (mean pollen dispersal distance 438.0 ± 51.7 m within the pasture and up to 50% external pollinations).…”

Section: Functional Agroecosystemsmentioning

confidence: 99%

Remnant Pachira quinata pasture trees have greater opportunities to self and suffer reduced reproductive success due to inbreeding depression

et al. 2013

View full text Add to dashboard Cite

Habitat fragmentation is extensive throughout the world, converting natural ecosystems into fragments of varying size, density and connectivity. The potential value of remnant trees in agricultural landscapes as seed sources and in connecting fragments has formed a fertile area of debate. This study contrasted the mating patterns of bat-pollinated Pachira quinata trees in a continuous forest to those in pasture through microsatellite-based paternity analysis of progeny. The breeding system was determined by analysis of pollen tube growth and seed production from controlled pollinations. Fitness of selfed and outcrossed seed was compared by germination and seedling growth. There was more inbreeding within pasture trees (outcrossing ¼ 0.828±0.015) compared with forest trees (0.926±0.005). Pasture trees had fewer sires contributing to mating events, but pollen dispersal distances were greater than those in the forest. Paternity analysis showed variation in outcrossing rates among pasture trees with high proportions of external and self pollen sources detected. A leaky self-incompatibility system was found, with self pollen having reduced germination on stigmas and slower growth rate through the style. Controlled pollinations also showed a varied ability to self among trees, which was reflected in the selfing rates among pasture trees shown by the paternity analysis (0-80% selfing). Self pollination resulted in lower seed set, germination and seedling growth compared with outcrossing. While remnant trees in agricultural landscapes are involved in broader mating patterns, they show increased but varied levels of inbreeding, which result in reduced fitness.

show abstract

“…However, conserving a number of small habitat patches such as sacred groves can have additional value for conserving biodiversity, for instance by covering a wider variety of habitats than would be achieved by protecting a few large patches of an equivalent total area (Bhagwat and Rutte 2006;Hokkanen et al 2009) and thus contributing to higher total biodiversity covered (Benedick et al 2006). Another important benefit is that a habitat network enabling dispersal amongst sacred groves and other protected areas (Laita et al 2010;Chiarucci et al 2012) may make an important contribution to genetic connectivity (Lander et al 2010) and the survival of species as metapopulations (sensu Hanski 1998). In particular when it is not feasible to maintain large tracts of pristine habitat, for instance because the landscape is intensively used as cropland after extensive past deforestation (Arroyo-Rodríguez et al 2009), the conservation and restoration of small habitat patches, such as sacred groves, may turn out to be the final safety net to conserve a high proportion of the landscape's previous biodiversity (Fischer and Lindenmayer 2002).…”

Section: Introductionmentioning

confidence: 99%

Conservation of the Ethiopian church forests: Threats, opportunities and implications for their management

Aerts

Overtveld

November

et al. 2016

Science of The Total Environment

102

View full text Add to dashboard Cite

In the central and northern highlands of Ethiopia, native forest and forest biodiversity is almost confined to sacred groves associated with churches. Local communities rely on these 'church forests' for essential ecosystem services including shade and fresh water but little is known about their region-wide distribution and conservation value. We (1) performed the first large-scale spatially-explicit assessment of church forests, combining remote-sensing and field data, to assess the number of forests, their size, shape, isolation and woody plant species composition, (2) determined their plant communities and related these to environmental variables and potential natural vegetation, (3) identified the main challenges to biodiversity conservation in view of plant population dynamics and anthropogenic disturbances, and (4) present guidelines for management and policy. The 394 forests identified in satellite images were on average ~2 ha in size and generally separated by ~2 km from the nearest neighboring forest. Shape complexity, not size, decreased from the northern to the central highlands. Overall, 148 indigenous tree, shrub and liana species were recorded across the 78 surveyed forests. Patch α-diversity increased with mean annual precipitation, but typically only 25 woody species occurred per patch. The combined results showed that >50% of tree species present in tropical northeast Africa were still present in the 78 studied church forests, even though individual forests were small and relatively species-poor. Tree species composition of church forests varied with elevation and precipitation, and resembled the potential natural vegetation. With a wide distribution over the landscape, these church forests have high conservation value. However, long-term conservation of biodiversity of individual patches and evolutionary potential of species may be threatened by isolation, small sizes of tree species populations and disturbance, especially when considering climate change. Forest management interventions are essential and should be supported by environmental education and other forms of public engagement.

show abstract

Fragmented but not isolated: Contribution of single trees, small patches and long-distance pollen flow to genetic connectivity for Gomortega keule, an endangered Chilean tree

Cited by 91 publications

References 51 publications

Contemporary pollen-mediated gene immigration reflects the historical isolation of a rare, animal-pollinated shrub in a fragmented landscape

Contemporary pollen-mediated gene immigration reflects the historical isolation of a rare, animal-pollinated shrub in a fragmented landscape

Remnant Pachira quinata pasture trees have greater opportunities to self and suffer reduced reproductive success due to inbreeding depression

Conservation of the Ethiopian church forests: Threats, opportunities and implications for their management

Contact Info

Product

Resources

About