Development of tree snail protection enclosures: From design to implementation

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.The Hawaiian land snails in the endangered, endemic genus Achatinella have experienced major declines in population and distribution over the last 100 years. Threats to Achatinella today include invasive, non‐native predators (Euglandina rosea, Rattus rattus and Trioceros jacksonii), habitat degradation due to human disturbance and possibly climate change, and historically, collection by humans. The O‘ahu Army Natural Resources Program (OANRP) is required to stabilize select remaining populations of A. mustelina. Stabilization goals are to maintain 300 mature snails at eight managed sites and control threats within sites. This report describes OANRP efforts to combat invasive predators by means of predator‐free and ‐proof snail enclosures. A couple of prior attempts at excluding predatory snails were marginally successful but the identification of additional predators required substantial additional barriers. The design and construction of the enclosure at Pu‘u Hapapa is used as a case study. This report includes detailed information on the physical development of predator‐proof barriers, construction and costs. Additional needs for monitoring and maintenance, predator removal, Achatinella reintroduction, Achatinella population monitoring, and habitat improvement were also developed.Funded by: U.S. Army via U.S. Army Corps of Engineers Cooperative Agreement W9126G-10-2-001

Inferring plant–plant interactions using remote sensing

Rapid technological advancements and increasing data availability have improved the capacity to monitor and evaluate Earth's ecology via remote sensing. However, remote sensing is notoriously ‘blind’ to fine-scale ecological processes such as interactions among plants, which encompass a central topic in ecology. Here, we discuss how remote sensing technologies can help infer plant–plant interactions and their roles in shaping plant-based systems at individual, community and landscape levels. At each of these levels, we outline the key attributes of ecosystems that emerge as a product of plant–plant interactions and could possibly be detected by remote sensing data. We review the theoretical bases, approaches and prospects of how inference of plant–plant interactions can be assessed remotely. At the individual level, we illustrate how close-range remote sensing tools can help to infer plant–plant interactions, especially in experimental settings. At the community level, we use forests to illustrate how remotely sensed community structure can be used to infer dominant interactions as a fundamental force in shaping plant communities. At the landscape level, we highlight how remotely sensed attributes of vegetation states and spatial vegetation patterns can be used to assess the role of local plant–plant interactions in shaping landscape ecological systems. Synthesis. Remote sensing extends the domain of plant ecology to broader and finer spatial scales, assisting to scale ecological patterns and search for generic rules. Robust remote sensing approaches are likely to extend our understanding of how plant–plant interactions shape ecological processes across scales—from individuals to landscapes. Combining these approaches with theories, models, experiments, data-driven approaches and data analysis algorithms will firmly embed remote sensing techniques into ecological context and open new pathways to better understand biotic interactions

Metadata html file

This is a metadata html file that was composed using R Markdown and executes R code. The required demographic parameter estimates can be uploaded from the associated Rda files associated with this archived Dryad Digital Repository http://doi:10.5061/dryad.4k7d5n7 (Bialic-Murphy et al. 2019). This file uses parameter coefficients calculated in a separate R script (not provided in our supplement) and builds annual integral projection models from 2010-2016 for four treatments: A) deer access and garlic mustard ambient, B) deer access and garlic mustard weeded, C) deer exclusion and garlic mustard ambient, and D) deer exclusion and garlic mustard weeded (i.e., removal of both stressors). Using the component matrices of the discretized kernel matrix (K=P+F), this script generates the annual population growth rates, the cumulative growth rates from 2010 to 2016 (λc), and the time-averaged geometric mean growth rate, which captures the time-averaged population growth rate over a single transition year (λper year = sixth root of λc)

Metadata and associated R code

This file uses parameter estimates calculated in a separate R script (not provided in our supplement) and builds three integral projection models (one at each level of deer impact). Using the component matrices of the discretized kernel matrix K=P+F+C, this script also projects even-aged cohorts of either newborn seedlings or clones using matrix P as an individual-based model. This document displays the R code we used to generate all demographic estimates reported in our article and also most of the figures. The required demographic parameters are listed in two comma-separated value files (.csv) that are included in with this supplement. Additionally, we included the output from the individual-based model projections to expedite computation. They are saved as R objects in R data files (.Rdata)

R data of individual-based model projections for sexually produced offspring

Section IV of the metadata HTML file

The reproductive coefficients

The reproductive coefficients csv file that is loaded in section 1 of the HTML file

Cyrtandra_dentata_matrices_2010_2014

This file contains mean transition matrices from 2010–2011, 2011–2012, 2012–2013, and 2013–2014 from a geographically isolated population of a long lived shrub, Cyrtandra dentata, from the Kahanahāiki Management Unit (36 ha), located in the northern Wai‘anae Mountain Range, on the island of O‘ahu (21° 32’ N, -158°12’ W

P.array2014

2014-2015 demographic parameter coefficients for Trillium for four treatments (see metafile)

Data from: Microhabitat heterogeneity and a non-native avian frugivore drive the population dynamics of an island endemic shrub, Cyrtandra dentata

Understanding of the role of environmental change in the decline of endangered species is critical to designing scale-appropriate restoration plans. For locally endemic rare plants on the brink of extinction, frugivory can drastically reduce local recruitment by dispersing seeds away from geographically isolated populations. Dispersal of seeds away from isolated populations can ultimately lead to population decline. For localized endemic plants, fine-scale changes in microhabitat can further limit population persistence. Evaluating the individual and combined impact of frugivores and microhabitat heterogeneity on the short-term (i.e. transient) and long-term (i.e. asymptotic) dynamics of plants will provide insight into the drivers of species rarity. In this study, we used four years of demographic data to develop matrix projection models for a long-lived shrub, Cyrtandra dentata (H. St. John & Storey) (Gesneriaceae), which is endemic to the island of O'ahu in Hawai'i. Furthermore, we evaluated the individual and combined influence of a non-native frugivorous bird, Leiothrix lutea, and microhabitat heterogeneity on the short-term and long-term C. dentata population dynamics. Frugivory by L. lutea decreased the short-term and long-term population growth rates. However, under the current level of frugivory at the field site the C. dentata population was projected to persist over time. Conversely, the removal of optimum microhabitat for seedling establishment (i.e. rocky gulch walls and boulders in the gulch bottom) reduced the short-term and long-term population growth rates from growing to declining. Survival of mature C. dentata plants had the greatest influence on long-term population dynamics, followed by the growth of seedlings and immature plants. The importance of mature plant survival was even greater when we simulated the combined effect of frugivory and the loss of optimal microhabitat, relative to population dynamics based on field conditions. In the short-term (10 years), however, earlier life stages had the greatest influence on population growth rate. Synthesis and applications. This study emphasizes how important it is to decouple rare plant management strategies in the short versus long-term in order to prioritize restoration actions, particularly when faced with multiple stressors not all of which can be feasibly managed. From an applied conservation perspective, our findings also illustrate that the life stage that, if improved by management, would have the greatest influence on population dynamics is dependent on the timeframe of interest and initial conditions of the population

Large-scale rodent control reduces pre- and post-dispersal seed predation of the endangered Hawaiian lobeliad, \u3ci\u3eCyanea superba\u3c/i\u3e subsp. \u3ci\u3esuperba\u3c/i\u3e (Campanulaceae)

Large-scale rodent control can help to manage endangered species that are vulnerable to invasive rodent consumption. A 26 ha rodent snap-trap grid was installed in montane forest on Oahu Island, Hawaii, in order to protect endangered snails and plants. To assess the effectiveness of this trapping operation in reducing fruit consumption and seed predation of the endangered Hawaiian lobeliad, Cyanea superba subsp. superba, pre- and post-dispersal C. superba fruit consumption were monitored for 36 plants at the site with rodent control (Kahanahaiki) and 42 plants at an adjacent site without rodent control (Pahole).Over 47 % of all monitored fruit were eaten on the plants at Pahole compared to 4 %at Kahanahaiki. Images captured using motion-sensing cameras suggest that black rats (Rattus rattus) were the only pre-dispersal fruit consumers. To quantify post-dispersal fruit consumption, and to identify the culprit frugivore(s), mature fruit were placed in tracking tunnels positioned on the forest floor and checked daily. At Pahole, all of the fruit were consumed by rats compared to 29 % at Kahanahaiki. Lastly, to determine if rodents from the sites were predators or dispersers of C. superba seed, fruit were fed to captive black rats and house mice (Mus musculus). Black rats consumed entire fruit, killing all the seed,while mice did little damage to the fruit and seed. Therefore, large-scale rat trapping can directly benefit the reproduction of C. superba subsp. superba. Controlling black rats at restoration sites appears integral to the successful restoration of this endangered plant species