Microsatellite DNA markers for delineating population structure and kinship among the endangered Kirtland's warbler (Dendroica kirtlandii)

We document the isolation and characterization of 23 microsatellite DNA markers for the endangered Kirtland's warbler (Dendroica kirtlandii), a Nearctic/Neotropical migrant passerine. This suite of markers revealed moderate to high levels of allelic diversity (averaging 7.7 alleles per locus) and heterozygosity (averaging 72%). Genotypic frequencies at 22 of 23 (95%) markers conformed to Hardy–Weinberg equilibrium expectations, and no linkage disequilibrium was observed in blood samples taken from 14 warblers found on the wintering grounds in the Bahamas archipelago. Multilocus genotypes resulting from this suite of markers should reduce the amount of resources required for initiating new genetic studies assessing breeding structure, parentage, demographics, and individual‐level ecological interactions for D. kirtlandii.     

Habitat and Landscape Effects on Brood Parasitism,Nest Survival,and Fledgling Production in Swainson's Warblers

ABSTRACT Numerous factors, including nest predation and brood parasitism, may limit populations of neotropical migratory birds. However, nest predation and brood parasitism are not constant, and temporal, biological, habitat, and landscape factors can affect the likelihood of these events. Understanding these patterns is important for species of conservation concern for which managers seek to provide quality habitat. One such species, the Swainson's warbler (Limnothlypis swainsonii), is a neotropical migrant that breeds primarily in bottomland hardwood forests of the southeastern United States. Little is known of factors influencing reproductive success of this rare, yet locally abundant, species. From 2004 through 2007, we examined factors influencing reproductive success of Swainson's warblers at 2 sites in eastern Arkansas, USA, St. Francis National Forest and White River National Wildlife Refuge. We used 2-stage modeling to assess the relationship between 1) temporal and biological, and 2) habitat and landscape factors and brood parasitism, nest survival, and fledgling production. Brood parasitism was greater in this population (36%) than reported elsewhere (≤ 10%), but decreased throughout the breeding season. Nest survival was comparable to or lower than in other populations of this species and increased throughout the breeding season. The probability of brood parasitism was greater near forest edges. Although nests of Swainson's warblers were often associated with giant cane (Arundinaria gigantea), nest survival had a weak negative association with cane density. For nests that were successful, the best predictor of number of Swainson's warblers fledged was brood-parasitism status: nonparasitized nests fledged 2.75 young, whereas parasitized nests fledged 0.60 Swainson's warblers. Our findings suggest that managing and restoring relatively high-elevation bottomland forests that are located far from agricultural edges should increase Swainson's warbler productivity.     

Identifying evolutionarily significant units for conservation of the endangered Malus sieversii using genome‐wide RADseq data

Malus sieversii, a wild progenitor of the domesticated apple, is an endangered species and is assigned second conservation priority by the China Plant Red Data Book. It is urgent to carry out in situ conservation of this species, but previous studies have not identified evolutionarily significant units (ESUs) for conservation management. In this study, we investigated the genetic diversity and relationships of six M. sieversii populations from China using integrated analysis of microsatellite (nSSR) data, genome‐wide SNPs and previous results in order to propose a reasonable conservation management. The results showed that levels of genetic diversity were inconsistently reflected by our nSSR and previous studies, suggesting that indices of genetic diversity are not effective to identify priority conservation areas for M. sieversii. Based on the selection criteria of ESUs for endangered species conservation, ESUs should reflect lineage divergence, geographical separation and different adaptive variation. Our phylogenetic tree based on genome‐wide SNPs yielded a clear relationship of divergent lineages among M. sieversii populations, leading to new different from those of previous studies. Three independent lineages, including the pairs of populations Huocheng‐Yining, Gongliu‐Xinyuan and Tuoli‐Emin, were identified. The geographic distances between populations among the different phylogenetic lineages were much greater than those within the same phylogenetic lineage. A cluster analysis on environmental variables showed that the three independent lineages inhabit different environmental conditions, suggesting that they may have adapted to different environments. Based on the results, we propose that three independent ESUs should be recognized as conservation units for M. sieversii in China.     

Saving the endangered Mary River turtle: Enhancing conservation outcomes through community engagement

Australian biodiversity is facing an extinction crisis; yet, government spending on conservation is wholly inadequate. The involvement of local communities in fundraising, direct actions, and habitat restoration is becoming vital in the fate of threatened species. Here, we review the research outputs and impact generated from 22 years of conservation-driven collaboration between researchers and a local community focused on saving the endangered Mary River turtle (Elusor macrurus). The study found that this collaboration generated a significant body of research that advanced the ecological knowledge of the species and ensured the findings were being applied towards the conservation of the turtle, locally and nationally. While the national listing status of E. macrurus as endangered has not changed over the past 22 years, the knowledge gained about the turtle's biology and its use to better advise development and water resources in the catchment suggests that the species' future is brighter than when it was first discovered in 1994. This review demonstrates the potential of local communities in driving and supporting conservation initiatives and provides a blueprint for scientific endeavours that inform adaptive community conservation programmes for threatened species.     

Management implications for the reintroduction of the endangered Hawaiian state flower Hibiscus brackenridgei

Dry forests of Hawai'i are one of the most endangered forest types worldwide with 45% of all native tree and shrub species listed as federally threatened or endangered. Supplementation and reintroduction of endangered dry forest species are necessary to maintain viable population sizes. The goal of this research was to reintroduce Hibiscus brackenridgei mokuleianus, the state flower of Hawai'i and a federally endangered species, into its historical range on O'ahu. We determined the environmental variables contributing to plant survival and growth, assessed the effectiveness of a reintroduction program with minimal management, and evaluated the potential for habitat suitability models to assist in selection of optimal sites for reintroduction. Forty‐five individuals were grown from cuttings and transplanted in two regions: Ka'ena Point (2 sites, 10 individuals each site) and along Kealia Trail (5 sites, 5 individuals each site). Survival and height measurements were taken four times over the course of 25 months. There was 35% survival at Ka'ena Point and 76% survival at Kealia Trail and an average plant growth of 70.5 cm (±30.1 cm) and 121.6 cm (±61.7 cm), respectively. Ka'ena Point had significantly lower survival (p > 0.001) and growth rates (p > 0.001) than Kealia Trail. Plants survived best at sites with steep slopes and high soil moisture and grew the most in sites with steeper slopes, higher soil moisture, and lower soil bulk density. These findings provide insight into environmental variables which should be considered prior to planting as well as the intensity of site management.     

Host activity and the risk of nest parasitism by brown-headed cowbirds

Proportions of nests parasitized by brown-headed cowbirds (Molothrus ater) vary greatly among host species, but factors underlyingthis variation remain poorly understood. Cowbirds are believedto find nests by watching host behavior. We tested the hypothesisthat the activity of hosts during nest building correlateswith the probability of parasitism among and within four sympatrichosts: dusky flycatchers (Empidonax oberholseri), warblingvireos (Vireo gilvus), yellow warblers (Dendroica petechia),and American redstarts (Setophaga ruticilla). Daily probabilityof parasitism varied substantially among these species, from3% for dusky flycatchers to more than four times that for warblingvireos. The four species did not differ in the proportion ofcowbirds fledged from their nests. Differences in nest placementdid not explain differences in probability of parasitism amongor within species. Parasitism frequencies increased among speciesthat made longer nest-building visits, had a greater propensityto perch during nest approach, spent more time near their nests,and had males that vocalized more often near nests. Within species, females that visited their nests less often, spent more timeon the nest per visit, and males that sang more and were activein a smaller area around their nests were more likely to beparasitized by cowbirds. These data support the hypothesisthat cowbirds use the activity of hosts during nest buildingto locate nests.     

Molecular and paleo-climatic data uncover the impact of an ancient bottleneck on the demographic history and contemporary genetic structure of endangered Pinus uliginosa

With the current rate of biodiversity loss, conservation management practices require a comprehensive understanding of eco-evolutionary relationships, history, and genetic structure of species. Assessments of genetic diversity are crucial, especially in rare, endemic, or threatened forest tree species with small and isolated populations, such as peat bog pine (Pinus uliginosa N.). Here, we used a novel approach, combining genetic diversity assessment, ecological niche modeling, and population demography inference to explore the complex history of a few remnant populations of this endangered pine. To asses the relative influence of isolation and fragmentation on genetic diversity in the taxonomic context, the patterns of genetic variation found in P. uliginosa were contrasted with those observed in its close relatives with much bigger distribution ranges and larger populations (Pinus sylvestris, Pinus mugo, and Pinus uncinata). We found a similar level of genetic diversity across the species at nuclear loci but contrasting patterns of variability distribution at chloroplast markers. We detected the signatures of an ancient genetic bottleneck dated at around 26 400 years ago, indicating a drastic reduction in the population size of P. uligionosa during the Last Glacial Maximum. In addition, we found substantial differentiation between current populations as a result of enhanced genetic drift during long-lasting isolation. The research suggests potential conservation management strategies for peat bog pine and emphasizes the importance of using complementary approaches for their successful development.     

The fundamental role of ecological feedback mechanisms for the adaptive management of seagrass ecosystems – a review

Seagrass meadows are vital ecosystems in coastal zones worldwide, but are also under global threat. One of the major hurdles restricting the success of seagrass conservation and restoration is our limited understanding of ecological feedback mechanisms. In these ecosystems, multiple, self‐reinforcing feedbacks can undermine conservation efforts by masking environmental impacts until the decline is precipitous, or alternatively they can inhibit seagrass recovery in spite of restoration efforts. However, no clear framework yet exists for identifying or dealing with feedbacks to improve the management of seagrass ecosystems. Here we review the causes and consequences of multiple feedbacks between seagrass and biotic and/or abiotic processes. We demonstrate how feedbacks have the potential to impose or reinforce regimes of either seagrass dominance or unvegetated substrate, and how the strength and importance of these feedbacks vary across environmental gradients. Although a myriad of feedbacks have now been identified, the co‐occurrence and likely interaction among feedbacks has largely been overlooked to date due to difficulties in analysis and detection. Here we take a fundamental step forward by modelling the interactions among two distinct above‐ and belowground feedbacks to demonstrate that interacting feedbacks are likely to be important for ecosystem resilience. On this basis, we propose a five‐step adaptive management plan to address feedback dynamics for effective conservation and restoration strategies. The management plan provides guidance to aid in the identification and prioritisation of likely feedbacks in different seagrass ecosystems.