Larval food limitation in a speyeria butterfly (Nymphalidae): How many butterflies can be supported?

For herbivorous insects the importance of larval food plants is obvious, yet the role of host abundance and density in conservation are relatively understudied. Populations of Speyeria butterflies across North America have declined and Speyeria adiaste is an imperiled species endemic to the southern California Coast Ranges. In this paper, we study the link between the food plant Viola purpurea quercetorum and abundance of its herbivore Speyeria adiaste clemencei to better understand the butterfly’s decline and aid in restoration of this and other Speyeria species. To assess the degree to which the larval food plant limits adult abundance of S. a. clemencei in 2013, we compared adult population counts to population size predicted from a Monte Carlo simulation using data for number of V. pur. quercetorum plants, number of leaves per plant, and leaf area per plant, with lab estimates of leaf area consumed to reach pupal stage on the non-native host V. papilionacea. Results indicated an average estimate of 765 pupae (median = 478), with 77% of the distribution being \u3c1000 pupae. However, this was heavily dependent on plant distribution, and accounting for the number of transect segments with sufficient host to support a pupa predicted 371 pupae. The adult population empirical estimate was 227 individuals (95% CI is 146 to 392), which lies near the first quartile of the simulated distribution. These results indicate that the amount of host available to larvae was more closely linked to adult abundance than the amount of host present, especially when considering assumptions of the analyses. The data also indicate that robust populations require host density well in excess of what is eaten by larvae, in combination with appropriate spacing, to mitigate factors such as competition, starvation from leaving host patches, or unrelated to food plant, such as mortality from drought, predators, parasites, or disease

Using Expert Knowledge to Satisfy Data Needs:Mapping Invasive Plant Distributions in the Western United States

Lack of knowledge about the distributions of plant and animal species can severely hamper management efforts. For invasive plants, distribution and abundance data can inform early detection and rapid response (EDRR) programs aimed at treating initial infestations. These data can be used to create invasion risk models at landscape and regional scales. Further, regional maps of invasive plant abundance are useful for communicating the scope of the invasive species problem to the public and policymakers. Here, we present a set of regional distribution maps for 10 problematic invasive plants in the western United States, created from the expert knowledge of weed managers in over 300 counties. Invasive plant experts identified infestations on paper, and the results were digitized into a regional GIS. Over 40% of requests were returned, resulting in maps with good spatial coverage and distribution data suitable for assessing invasive plant abundance across the western United States. Cheatgrass (Bromus tectorum) and Canada thistle (Cirsium arvense) were the most abundant and widespread of the surveyed species; however, the high concentrations and broad spatial extents of other invasive plants, such as hounds tongue (Cynoglossum officinale), white top (Lepidium draba), and Dalmatian toadflax (Linaria dalmatica), highlight the ongoing problems invasive species pose for western ecosystems, rangelands, and croplands. These results reinforce the critical role that regional mapping efforts can play in assessing and communicating invasion risk. This study suggests that knowledge about plant invasions exists locally and that experts are willing to participate in regional efforts to compile that information

Non-overlapping Distributions of Feral Sheep (Ovis aries) and Stout Iguanas (Cyclura pinguis) on Guana Island, British Virgin Islands

Stout Iguanas (Cyclura pinguis) remain one of the most critically endangered reptiles in the world. Factors contributing to that status include habitat loss, predation by introduced species, and competition with introduced herbivores. On Guana Island, British Virgin Islands, the presence of feral sheep (Ovis aries) has been a hypothesized detriment to iguanas. Using motion sensitive cameras, we documented the distribution of feral sheep on Guana Island in 2010. We also quantified the impact of feral sheep on ground vegetation by comparing plant abundance at long term sheep exclosures and areas where sheep were absent to areas where sheep were present. Finally, we compared sheep distribution to iguana distribution on the island. The co-occurrence of sheep and Stout Iguanas was less than expected, indicating possible competition. Although we detected no difference in vegetative cover between areas where sheep were present and absent, the long-term exclosures showed that the exclusion of sheep allowed the abundance of many plant species to increase. Our data support the hypothesis that feral sheep are altering the abundance of ground-level vegetation and limiting iguana distribution on the island

Spatial Joint Species Distribution Modeling using Dirichlet Processes

Species distribution models usually attempt to explain presence-absence or abundance of a species at a site in terms of the environmental features (socalled abiotic features) present at the site. Historically, such models have considered species individually. However, it is well-established that species interact to influence presence-absence and abundance (envisioned as biotic factors). As a result, there has been substantial recent interest in joint species distribution models with various types of response, e.g., presence-absence, continuous and ordinal data. Such models incorporate dependence between species response as a surrogate for interaction. The challenge we focus on here is how to address such modeling in the context of a large number of species (e.g., order 102) across sites numbering in the order of 102 or 103 when, in practice, only a few species are found at any observed site. Again, there is some recent literature to address this; we adopt a dimension reduction approach. The novel wrinkle we add here is spatial dependence. That is, we have a collection of sites over a relatively small spatial region so it is anticipated that species distribution at a given site would be similar to that at a nearby site. Specifically, we handle dimension reduction through Dirichlet processes joined with spatial dependence through Gaussian processes. We use both simulated data and a plant communities dataset for the Cape Floristic Region (CFR) of South Africa to demonstrate our approach. The latter consists of presence-absence measurements for 639 tree species on 662 locations. Through both data examples we are able to demonstrate improved predictive performance using the foregoing specification

Lignin content and chemical characteristics in maize and wheat vary between plant organs and growth stages: consequences for assessing lignin dynamics in soil

Assessing lignin turnover in soil on the basis of a 13C natural abundance labeling approach relies on the assumption that chemical characteristics of labeled and control plant inputs are similar and that the 13C content difference between labeled and control plant inputs is constant within the plant parts. We analyzed lignin in soils, roots, stems and leaves of wheat and maize at different stages of growth using the cupric oxide oxidation method. In both plants, lignin concentrations increased with growth, particularly during grain filling. Maize contained more cinnamyl moieties than wheat. Roots had higher lignin contents (especially cinnamyl moieties) than stems and leaves, and seemed to contribute more to the total soil lignin than the aboveground parts. The isotopic differences (∆ δ13C) of lignin phenols were not significantly different (p > 0.05) between plant organs, confirming assumptions underlying the natural abundance 13C labeling approach. Our data show that lignin content and phenol distribution can vary between plant organs and with the time of harvest. Consequently, the amount of annual lignin input may vary as a function of root amount and harvest date, and thus can affect the calculated apparent turnover times of lignin in natural abundance 13C labeling experiment

Long‐term trends in the distribution, abundance and impact of native “injurious” weeds

Questions: How can we quantify changes in the distribution and abundance of injurious weed species (Senecio jacobaea, Cirsium vulgare, Cirsium arvense, Rumex obtusifolius, Rumex crispus and Urtica dioica), over long time periods at wide geographical scales? What impact do these species have on plant communities? To what extent are changes driven by anthropogenically induced drivers such as disturbance, eutrophication and management? Location: Great Britain. Methods: Data from national surveys were used to assess changes in the frequency and abundance of selected weed species between 1978 and 2007. This involved novel method development to create indices of change, and to relate changes in distribution and abundance of these species to plant community diversity and inferred changes in resource availability, disturbance and management. Results: Three of the six weed species became more widespread in GB over this period and all of them increased in abundance (in grasslands, arable habitats, roadsides and streamsides). Patterns were complex and varied by landscape context and habitat type. For most of the species, there were negative relationships between abundance, total plant species richness, grassland, wetland and woodland indicators. Each individual species responds to a different combination of anthropogenic drivers but disturbance, fertility and livestock management significantly influenced most species. Conclusions: The increase in frequency and abundance of weeds over decades has implications for landscape‐scale plant diversity, fodder yield and livestock health. This includes reductions in plant species richness, loss of valuable habitat specialists and homogenisation of vegetation communities. Increasing land‐use intensity, excessive nutrient input, overgrazing, sward damage, poaching and bare ground in fields and undermanagement or too frequent cutting on linear features may have led to increases in weeds. These weeds do have conservation value so we are not advocating eradication, rather co‐existence, without dominance. Land management policy needs to adapt to benefit biodiversity and agricultural productivity

Distribution, Abundance and Socio-Economic Impacts of Parthenium (Parthenium hysterophorus) in Southern Zone of Tigray, Ethiopia

Parthenium hysterophorus is spreading at alarming rate, threatening agricultural ecosystem, biodiversity, human and animal health in the study area as well as in the country. There is a paucity of information regarding the spread and distribution of Parthenium in the Region in specific and the country in general. Hence, objectives of the study were: to determine the distribution and abundance level, to develop distribution and abundance map and to assess the socio-economic impacts of Parthenium based on communities perception. The biophysical data was recorded from abundance level observation of Parthenium using hand held GPS and analyzed by Arc GIS to make the distribution and abundance maps. The socio-economic survey was conducted through interview using semi-structured questionnaires and data has analyzed using SPSS software. The biophysical survey result showed that Parthenium was the major invasive alien plant species in the study area. Parthenium was found in all the Districts but abundantly found in Alamata and Raya Azebo Districts. The socio-economic impact assessment result indicated that expected to be introduced unintentionally by different agents, i.e. food aid and through livestock movement from neighboring Regions. Perception of the respondents indicated that Parthenium has negative impacts on biodiversity, agricultural ecosystem, human and animal health. Assessment widely in the Region is very important to collect information and status of Parthenium. This used to plan research priorities and facilitates sustainability and success of future control programs. Keywords: Parthenium hysterophorus,  distribution, abundance   and socio-economic impacts.

FloraSNevada: a trait database of the vascular flora of Sierra Nevada, southeast Spain

The complete data sets corresponding to abstracts published in theData Papers section in the journal are published electronically asSupportingInformationintheonlineversionofthisarticleat http://onlinelibrary.wiley.com/doi/10.1002/ecy.3091/suppinfoAssociated data are also available at PANGAEA: https://doi.org/10.1594/PANGAEA.910792Providing a complete data set with species and trait information for a given area is essential for assessing plant conservation, management, and ecological restoration, for both local and global applications. Also, these data sets provide additional information for surveys or data collections, establishing the starting point for more detailed studies on plant evolution, vegetation dynamics, and vegetation responses to disturbance and management. This data base covers Sierra Nevada mountains (southeastern Spain), a recognized plant biodiversity hotspot within the Mediterranean context. According to previous available data (before this augmented compilation), these mountains host 7% of the 24,000 Mediterranean vascular plants, despite covering just 0.01% of its area. Another characteristic of the Sierra Nevada is the great singularity of its flora, with 95 taxa being endemic to the high-mountain area of Sierra Nevada and surroundings. From these endemic taxa, 70% are endangered by different threats, global warming being a leading cause. We seek to provide a complete and updated database of the flora of the Sierra Nevada mountains (southeast Spain). The goal of the present data set is to compile the names of all the vascular plant taxa inhabiting Sierra Nevada, together with relevant features including taxonomical, morphological-ecological traits, distribution, habitats, abundance, and conservation status. The data were compiled according to all the available information sources on taxonomy, ecology, and plant-species distribution. The resulting data set includes 2,348 taxa belonging to 1,937 species, 377 subspecies, and 34 hybrids, from a total of 756 genera and 146 families represented in the collection. For each taxa, together with taxonomical information (Phylum, Class, Family, Genus, Taxa), we compiled plant traits (life form, spinescence, flower symmetry, flower sexuality, plant gender, androecium:ginoecium ratio, flower color, perianth type, pollinator type, flowering, seed dispersal, and vegetative reproduction), and their environmental association (origin, endemic character, general distribution, substrate, elevation, habitat, local abundance, hygrophilous behavior, and conservation status). All these traits were compiled from all the available information sources, resulting in a complete and updated database for Sierra Nevada vascular flora. This data set provides valuable information on plant traits in an outstanding micro hotspot within the Mediterranean hotspot. This data set can be freely used for non commercial purposes

Classification and mapping of the woody vegetation of Gonarezhou National Park, Zimbabwe

Within the framework of the Great Limpopo Transfrontier Conservation Area (GLTFCA), the purpose of this study was to produce a classification of the woody vegetation of the Gonarezhou National Park, Zimbabwe, and a map of its potential distribution. Cover-abundance data of woody species were collected in 330 georeferenced relevés across the Park. These data were used to produce two matrices: the first one using the cover-abundance values as collected in five height layers and the second one based on merging the layers into a single cover value for each species. Automatic classifications were produced for both matrices to determine the optimal number of vegetation types. The two classification approaches both produced 14 types belonging to three macro-groups: mopane, miombo and alluvial woodlands. The results of the two classifications were compared looking at the constant, dominant and diagnostic species of each type. The classification based on separate layers was considered more effective and retained. A high-resolution map of the potential distribution of vegetation types for the whole study area was produced using Random Forest. In the model, the relationship between bioclimatic and topographic variables, known to be correlated to vegetation types, and the classified relevés was used. Identified vegetation types were compared with those of other national parks within the GLTFCA, and an evaluation of the main threats and pressures was conducted. Conservation implications: Vegetation classification and mapping are useful tools for multiple purposes including: surveying and monitoring plant and animal populations, communities and their habitats, and development of management and conservation strategies. Filling the knowledge gap for the Gonarezhou National Park provides a basis for standardised and homogeneous vegetation classification and mapping for the entire Great Limpopo Transfrontier Conservation Area