Plant Species Of Conservation Concern Research Articles

Abandonment or biomass production? Phytodiversity responses to land-use changes of semi-natural grasslands in northern Europe

European semi-natural grasslands are hotspots for biodiversity and important for the provisioning of multiple ecosystem services, but their extent has declined considerably during the past century. Increasing demands for agricultural and forest biomass risk causing further loss of grasslands, raising concern about a goal conflict between climate mitigation and biodiversity conservation. This study focused on the loss of semi-natural grasslands in a mixed farm-forest landscape in southern Sweden by comparing plant diversity in grasslands with continuous grazing regimes to recently abandoned grasslands, improved grasslands (sown leys), and afforested grasslands. Compared to actively grazed grasslands, grasslands where grazing had been abandoned showed a lower plant species richness and fewer plant species of conservation concern, but similar species composition. In contrast, both improved and afforested grasslands showed >50 % lower species richness than abandoned and grazed grasslands, with profoundly different species composition. The dissimilarity in plant diversity between sites was primarily driven by the replacement of species (turnover), and trait-based analyses indicated that environmental filtering of light, management, and nutrient requirements of plants shaped the community differences. Furthermore, an increased cover of semi-natural grassland around the sites positively related to plant species richness and diversity, while an increased cropland coverage around the sites showed a negative relationship. Our results emphasize the importance of integrated land-use strategies that prioritize biodiversity conservation in mixed farm-forest landscapes, such as restoration of semi-natural grasslands and strategic planning of biomass production to avoid serious biodiversity losses.

Online wildlife trade in species of conservation concern

AbstractOnline wildlife trade is widespread and affects thousands of species. Yet, attempts to quantify online wildlife trade have mainly focused on a few platforms and taxonomic groups. Here, we study the prevalence of wildlife trade using automated data collection and filtering methods. We analyze trade across five digital platforms and 156 animal and plant species of conservation concern from a global biodiversity hotspot, the Philippines. We identified approximately 5000 highly relevant instances of trade in 1.47 million posts, focusing on 108 species, 79 of which are classified as threatened. Trade mainly occurred on webpages indexed in Google and on Twitter. We found that manual validation is essential, as animals obtained a higher proportion of hits prior to validation. Following manual validation, we observed a shift toward plant‐related trade hits. Scaling up these approaches to a global level is key to understanding the extent of digital wildlife trade across the globe.

Identifying bottlenecks in the life cycle of plants living on cliffs and rocky slopes: Lack of knowledge hinders conservation actions

Long term survival of plant populations relies on successful reproductive cycle to obtain generation turnover. Focusing on plant species of conservation concern, we brought together a group of plant conservationists from different countries to assess whether the already available information on plant reproductive biology and autecology is adequate for identifying which phases of single species life cycle might act as bottleneck.We compiled a list of 80 plant species of conservation concern living on European cliffs and rocky slopes, for which biological and autecological information was collected from scientific literature, technical reports, and expert knowledge.Results have shown that the available information on species reproductive biology and autecology is inadequate to identify bottlenecks in the life cycle of many species and to provide insights for the practical conservation of many more. Available knowledge is mainly referred to the flowering phase, less on seed production and much less on seedling establishment and on cloning. Meanwhile and noteworthy, flowering resulted to be the less critical phase for the fulfilment of the species life cycle.Overall, with this perspective article we aim to encourage a constructive debate among the scientific community members and policymakers to set up novel concerted strategies for the conservation of plant species of conservation concern. The challenge of the discussion is the implementation of the current approach with new biological and ecological information to be exclusively targeted at identifying the constraints that limit the generation turnover and furnishing specific indications for active management.

Quantifying the distribution and potential biotic interactions between deer and flora using species distribution modelling

ABSTRACT Invasive species are ranked as one of the leading drivers of global biodiversity loss. To mitigate their impact, we must understand the future risks caused by invasive species, particularly to flora of conservation concern. Here we used species distribution modelling (SDM) to project the current and future (RCP45 and RCP85 2050) distributions of four deer species and 13 plant species of conservation concern for the island of Ireland, quantifying changes in distributions and overlap. Large areas of suitable habitat for the deer species were predicted with high accuracy across all counties, with future climate scenarios identifying an expansion in sika deer distributions and a decrease in muntjac and fallow deer distributions. Red deer declined under the moderate climate change scenario but increased under the worst-case projection. Future projections predicted the (local) extinction of six (out of 13) endangered and vulnerable plant species. An expansion in distributions was observed for four plant species; however, these areas had large overlap with the future predictions of deer, placing further pressures on these plant species. These findings suggest that targeted conservation and management measures are required to alleviate the pressures on ‘at-risk’ plant species due to grazing from native and non-native deer.

Multiple intrinsic and extrinsic drivers influence the quantity and quality components of seed dispersal effectiveness in the rare shrub Lindera subcoriacea.

Information about seed dispersal effectiveness (SDE) for plant species of conservation concern is rarely available to inform management strategies and actions. For Lindera subcoriacea (bog spicebush, Lauraceae), a rare endemic dioecious shrub of the southeastern United States, we examined the influence of two intrinsic and five extrinsic drivers on the number and proportion of seeds either dispersed, or predated pre- and post-dispersal. The number of seeds dispersed characterizes the quantitative component of SDE, while pre- and post-dispersal seed predation can affect the qualitative component of SDE. Using fruit counts, seed traps, and seed removal depots over multiple years, we estimated that approximately 28% of L. subcoriacea seeds are lost to pre-dispersal predation, 69% of seeds are dispersed, 3% of seeds fail to disperse, and 65% of dispersed seeds are predated post-dispersal. We observed substantial variation in these three processes among individuals. We also found that both intrinsic (plant height, crop size) and extrinsic (understory cover, time since last fire, conspecific fruiting neighborhood, substrate) drivers differentially influenced the three processes. We identified four generalist, seasonally frugivorous, avian visitors at fruiting individuals that likely act as variably effective dispersers, while the Northern Cardinal (Cardinalis cardinalis L.) is a seed predator. Rodent granivores were important pre- and post-dispersal seed predators. The magnitude of our pre-dispersal and post-dispersal seed predation estimates suggest that, given the low fecundity of L. subcoriacea, conservation strategies should emphasize facilitating dispersal and reducing the effects of seed predation.

Five-Year Effects of Introduced Mountain Goats and Recreation on Plant Communities and Species of Conservation Concern in an Alpine Sky Island

Alpine ecosystems in the arid southwestern United States are vulnerable to climate change. Many of these ecosystems are experiencing increased recreational use and introductions of nonindigenous ungulates. In the La Sal Mountains of southeastern Utah, alpine plant communities support an endemic plant species, Erigeron mancus, 11 plant and two animal species of conservation concern, and a United States Department of Agriculture (USDA) Forest Service Research Natural Area. Nonindigenous mountain goats (Oreamnos americanus) were introduced by the Utah Division of Wildlife Resources (UDWR) in 2013 and 2014, and recreational use has increased in the intervening period. To evaluate potential effects of mountain goat and recreational use, vegetation monitoring was initiated by the USDA Forest Service in 2016. We used 5 y monitoring data (2016–2020) and generalized linear mixed models to analyze the separate and interacting effects of year, recreational use, and mountain goat use on: (1) populations of plant species of conservation concern; (2) vascular and nonvascular plant cover; and (3) ground cover. Our analyses revealed decreases in proportional frequency of E. mancus at the end of the monitoring. Proportional cover of dominant plant growth forms, especially forbs, declined, while proportional cover of litter and ineffective ground cover (bare soil and pavement) increased. Recreational or goat use were a factor in several of the observed changes, although weather and climate likely also influenced the results. Management complexity arises because of the different missions of USDA Forest Service and UDWR, but adjustments in mountain goat numbers and recreational use may be needed to maintain ecologically resilient ecosystems. Continued monitoring can provide the basis for adaptive management.

A quick glance at noteworthy articles for September 2021

A quick glance at noteworthy articles for September 2021

Using drone imagery analysis in rare plant demographic studies

For plant species of conservation concern, knowledge of changes in abundance through time is a minimum requirement for informed management. This information is usually acquired through on-the-ground monitoring, which entails counting individuals in defined areas over multiple years. Demographic studies, which involve tracking individual plants through time, are usually carried out at limited spatial scales and over shorter time frames than monitoring, but are more useful to management. In this study we explored the use of drone (UAV or unmanned aerial vehicle) imagery analysis as a tool for collecting demographic data for dwarf bear poppy (Arctomecon humilis), an endangered species restricted to gypsum outcrops in the northeastern Mojave Desert, USA. We obtained imagery at 15 m altitude during peak flowering at four populations in spring 2019. Each poppy plant in the imagery was georeferenced, measured and scored for flowering. To estimate reproductive output, we developed independent data sets relating plant diameter to flower number, then sampled to determine mean fruit set per flower and seeds per fruit. We used these relationships along with plant diameter and reproductive status for each plant in the drone imagery to estimate seed rain on an area basis across nine 0.6 ha demography plots at each population. This method enabled us to collect demographic data on >3,000 plants, including estimated production of ca. 3.7 million seeds, across >20 ha of habitat. We also analyzed imagery acquired in both 2018 and 2019 at two of the four populations and quantified recruitment, growth, and mortality of individual georeferenced plants. Our study is among the first to demonstrate the utility of drone imagery analysis in plant demographic studies. The method is most applicable for non-clonal perennial species with distinctive morphology that occur in habitats with low vegetative cover.

Intensity of grass invasion negatively correlated with population density and age structure of an endangered dune plant across its range

Invasive species are a global threat to ecosystem biodiversity and function; non-native grass invasion has been particularly problematic in sparsely vegetated ecosystems such as open dunes. Native plant population responses to invasion, however, are infrequently translated to landscape scales, limiting the effectiveness of these data for addressing conservation issues. We quantified population density, total population size, and age class distribution of the federally-endangered plant species Antioch Dunes evening primrose (Oenothera deltoides subsp. howellii), at sites along a non-native grass invasion gradient in California, USA. We then scaled relationships between invasion and plant density across the species’ range using spatial models and remote sensing data. Adult and juvenile O. deltoides subsp. howellii densities were more than 10 times higher in non-invaded areas (grids with 10% total plant cover) when compared to highly-invaded areas (grids with 80% total plant cover). The ratio of O. deltoides subsp. howellii juveniles to adults decreased to less than 1 at 54% total cover, highlighting sensitivity of the regeneration niche to invasion. Spatial models mapped hotspots of O. deltoides subsp. howellii abundance and population structure across the landscape at sub-meter scales. Scaling the impacts of increasing invasion on plant species of conservation concern holds promise when coupled with remote sensing approaches, especially in naturally low-cover ecosystems where readily available metrics (e.g., Normalized Difference Vegetation Index) can be used to quantify invasion. These spatial models inform how future invasive species management may influence population size and spatial distribution of species of conservation concern.

Do traits of plant species predict the efficacy of species distribution models for finding new occurrences?

Species distribution models (SDMs) are used to test ecological theory and to direct targeted surveys for species of conservation concern. Several studies have tested for an influence of species traits on the predictive accuracy of SDMs. However, most used the same set of environmental predictors for all species and/or did not use truly independent data to test SDM accuracy. We built eight SDMs for each of 24 plant species of conservation concern, varying the environmental predictors included in each SDM version. We then measured the accuracy of each SDM using independent presence and absence data to calculate area under the receiver operating characteristic curve (AUC) and true positive rate (TPR). We used generalized linear mixed models to test for a relationship between species traits and SDM accuracy, while accounting for variation in SDM performance that might be introduced by different predictor sets. All traits affected one or both SDM accuracy measures. Species with lighter seeds, animal‐dispersed seeds, and a higher density of occurrences had higher AUC and TPR than other species, all else being equal. Long‐lived woody species had higher AUC than herbaceous species, but lower TPR. These results support the hypothesis that the strength of species–environment correlations is affected by characteristics of species or their geographic distributions. However, because each species has multiple traits, and because AUC and TPR can be affected differently, there is no straightforward way to determine a priori which species will yield useful SDMs based on their traits. Most species yielded at least one useful SDM. Therefore, it is worthwhile to build and test SDMs for the purpose of finding new populations of plant species of conservation concern, regardless of these species’ traits.

Assessing the multi-scale predictive ability of ecosystem functional attributes for species distribution modelling.

Global environmental changes are rapidly affecting species’ distributions and habitat suitability worldwide, requiring a continuous update of biodiversity status to support effective decisions on conservation policy and management. In this regard, satellite-derived Ecosystem Functional Attributes (EFAs) offer a more integrative and quicker evaluation of ecosystem responses to environmental drivers and changes than climate and structural or compositional landscape attributes. Thus, EFAs may hold advantages as predictors in Species Distribution Models (SDMs) and for implementing multi-scale species monitoring programs. Here we describe a modelling framework to assess the predictive ability of EFAs as Essential Biodiversity Variables (EBVs) against traditional datasets (climate, land-cover) at several scales. We test the framework with a multi-scale assessment of habitat suitability for two plant species of conservation concern, both protected under the EU Habitats Directive, differing in terms of life history, range and distribution pattern (Iris boissieri and Taxus baccata). We fitted four sets of SDMs for the two test species, calibrated with: interpolated climate variables; landscape variables; EFAs; and a combination of climate and landscape variables. EFA-based models performed very well at the several scales (AUCmedian from 0.881±0.072 to 0.983±0.125), and similarly to traditional climate-based models, individually or in combination with land-cover predictors (AUCmedian from 0.882±0.059 to 0.995±0.083). Moreover, EFA-based models identified additional suitable areas and provided valuable information on functional features of habitat suitability for both test species (narrowly vs. widely distributed), for both coarse and fine scales. Our results suggest a relatively small scale-dependence of the predictive ability of satellite-derived EFAs, supporting their use as meaningful EBVs in SDMs from regional and broader scales to more local and finer scales. Since the evaluation of species’ conservation status and habitat quality should as far as possible be performed based on scalable indicators linking to meaningful processes, our framework may guide conservation managers in decision-making related to biodiversity monitoring and reporting schemes.

Deep-learning Versus OBIA for Scattered Shrub Detection with Google Earth Imagery: Ziziphus lotus as Case Study

There is a growing demand for accurate high-resolution land cover maps in many fields, e.g., in land-use planning and biodiversity conservation. Developing such maps has been traditionally performed using Object-Based Image Analysis (OBIA) methods, which usually reach good accuracies, but require a high human supervision and the best configuration for one image often cannot be extrapolated to a different image. Recently, deep learning Convolutional Neural Networks (CNNs) have shown outstanding results in object recognition in computer vision and are offering promising results in land cover mapping. This paper analyzes the potential of CNN-based methods for detection of plant species of conservation concern using free high-resolution Google Earth TM images and provides an objective comparison with the state-of-the-art OBIA-methods. We consider as case study the detection of Ziziphus lotus shrubs, which are protected as a priority habitat under the European Union Habitats Directive. Compared to the best performing OBIA-method, the best CNN-detector achieved up to 12% better precision, up to 30% better recall and up to 20% better balance between precision and recall. Besides, the knowledge that CNNs acquired in the first image can be re-utilized in other regions, which makes the detection process very fast. A natural conclusion of this work is that including CNN-models as classifiers, e.g., ResNet-classifier, could further improve OBIA methods. The provided methodology can be systematically reproduced for other species detection using our codes available through (https://github.com/EGuirado/CNN-remotesensing).

Pollination and Reproductive Biology in a Hill Prairie Population of Nothocalais cuspidata (Asteraceae: Cichorieae)

Nothocalais cuspidata (Pursh) Greene (Asteraceae) is a plant species of conservation concern in Missouri; it typically occurs as isolated populations in hill and sand prairies which are themselves rare and fragmented habitats. The present study was undertaken to understand its reproductive biology as a hill prairie member and the possibility of reduced reproductive output in this isolated habitat. Nothocalais cuspidata is an early spring-flowering, nonclonal, primarily self-incompatible perennial that exhibits a 4 wk flowering phenology with most florets open to cross-pollination over a 2–3 wk period. The attractive UV reflective florets were visited by six species of halictid and solitary bees. The study population did experience depressed reproductive output in 2014 compared to 2004, with open-pollinated florets producing 19.1% fewer fruits than in 2004 along with a 37% decline in population size over a 13 y period. We suggest the depressed fruit production experienced is likely due to the unpredictable spring weather associated with early flowering and sporadic pollinator visitation in an isolated habitat leading to large variations in reproductive success over time or a reduction in compatible mating types as the population declines.

Potential of satellite-derived ecosystem functional attributes to anticipate species range shifts

In a world facing rapid environmental changes, anticipating their impacts on biodiversity is of utmost relevance. Remotely-sensed Ecosystem Functional Attributes (EFAs) are promising predictors for Species Distribution Models (SDMs) by offering an early and integrative response of vegetation performance to environmental drivers. Species of high conservation concern would benefit the most from a better ability to anticipate changes in habitat suitability. Here we illustrate how yearly projections from SDMs based on EFAs could reveal short-term changes in potential habitat suitability, anticipating mid-term shifts predicted by climate-change-scenario models. We fitted two sets of SDMs for 41 plant species of conservation concern in the Iberian Peninsula: one calibrated with climate variables for baseline conditions and projected under two climate-change-scenarios (future conditions); and the other calibrated with EFAs for 2001 and projected annually from 2001 to 2013. Range shifts predicted by climate-based models for future conditions were compared to the 2001–2013 trends from EFAs-based models. Projections of EFAs-based models estimated changes (mostly contractions) in habitat suitability that anticipated, for the majority (up to 64%) of species, the mid-term shifts projected by traditional climate-change-scenario forecasting, and showed greater agreement with the business-as-usual scenario than with the sustainable-development one. This study shows how satellite-derived EFAs can be used as meaningful essential biodiversity variables in SDMs to provide early-warnings of range shifts and predictions of short-term fluctuations in suitable conditions for multiple species.

The importance of herbivore density and management as determinants of the distribution of rare plant species

Herbivores are often drivers of ecosystem states and dynamics and in many situations are managed either as livestock or through controlled or exploitative hunting of wild populations. Changes in herbivore density can affect the composition of plant communities. Management of herbivore densities could therefore be regulated to benefit plant species of conservation concern. In this study we use a unique spatial dataset of large herbivores in Norway to test whether herbivore density affects the distribution of rare red-listed plant species in tundra ecosystems, and to identify regions where herbivore density is the most important factor in determining the habitat suitability for the plant species. For all selected species a climatic variable was the most important determinant of the distribution, but herbivore density was an important determinant of some species notably Primula scandinavica. Herbivore density was the most important factor determining habitat suitability for this species in 13% of mainland Norway. Regions of Norway where the management of herbivore densities is most strongly linked to the habitat suitability of red-listed plant species are mapped. However, there was very low concordance in the localities of these areas; at any individual locality, habitat suitability was limited by herbivore density for only a small subset of the species. This suggests that management of herbivores for the benefit of rare plant species needs to be tailored for individual locations or species.

Overcoming limitations of modelling rare species by using ensembles of small models

SummarySpecies distribution models (SDMs) have become a standard tool in ecology and applied conservation biology. Modelling rare and threatened species is particularly important for conservation purposes. However, modelling rare species is difficult because the combination of few occurrences and many predictor variables easily leads to model overfitting. A new strategy using ensembles of small models was recently developed in an attempt to overcome this limitation of rare species modelling and has been tested successfully for only a single species so far. Here, we aim to test the approach more comprehensively on a large number of species including a transferability assessment.For each species, numerous small (here bivariate) models were calibrated, evaluated and averaged to an ensemble weighted byAUCscores. These ‘ensembles of small models’ (ESMs) were compared to standardSDMs using three commonly used modelling techniques (GLM,GBMand Maxent) and their ensemble prediction. We tested 107 rare and under‐sampled plant species of conservation concern in Switzerland.We show thatESMs performed significantly better than standardSDMs. The rarer the species, the more pronounced the effects were.ESMs were also superior to standardSDMs and their ensemble when they were evaluated using a transferability assessment.By averaging simple small models to an ensemble,ESMs avoid overfitting without losing explanatory power through reducing the number of predictor variables. They further improve the reliability of species distribution models, especially for rare species, and thus help to overcome limitations of modelling rare species.

The distribution of vascular plant species of conservation concern in Ireland, and their coincidence with designated areas

Protected areas (that are usually designated) play an important role in the effort to halt on-going losses of biodiversity. However, areas outside of designated sites for protection can also hold important elements of biodiversity, and knowledge of their distribution is necessary to ensure effective conservation strategies. We collated and mapped vascular plant distribution data for species of conservation concern on the island of Ireland. For the first time in Ireland, we extracted 6078 distribution records of 176 species of conservation concern and mapped them at the tetrad (2km×2km) scale. We examined the extent to which tetrads with records of species of conservation concern overlapped with designated areas (Natura 2000, Natural Heritage Areas, Areas of Special Scientific Interest). A conservative estimate suggests that many of these tetrads do not overlap with designated areas (in the range of 22–40% for available records). The coincidence of records of individual species with designated areas ranged from 0% to 100% (mean=79%). The mapped distribution data for all vascular plant species offers guidance to where additional recording may be helpful in supporting conservation activities. The analysis of the distribution of species of conservation concern indicates the importance of both designated areas and the (non-designated) wider countryside for biodiversity conservation. In particular the presence of species of conservation concern in non-designated areas highlights the need for conservation measures outside of designated areas.

In Vitro Methods and the Challenge of Exceptional Species for Target 8 of the Global Strategy for Plant Conservation1

Abstract For the majority of plant species of conservation concern, seed banking and traditional propagation methods are the most efficient ways of meeting the ex situ and recovery conservation goals of Global Strategy for Plant Conservation (GSPC) Target 8. However, there are estimated to be 5000 or more endangered species for which these methods will not be adequate conservation tools. These “exceptional” species are those with recalcitrant seeds or those that produce few or no seeds. In vitro methods can provide alternative procedures for propagating and preserving germplasm in the long term for these species. Research at the Center for Conservation and Research of Endangered Wildlife (CREW) with several U.S. endangered species has shown the potential of these methods. In vitro propagation can provide plants for reintroduction and research when traditional propagation methods are not adequate. Phytotissue banking can be used for long-term ex situ conservation when seed or embryo banking is not possible...

Identifying plant species and communities across environmental gradients in the Western Himalayas: Method development and conservation use

Phytosociological attributes of plant species and associated environmental factors were measured in order to identify the environmental gradients of major plant communities in the Naran Valley, Himalayas. The valley occupies a distinctive geographical setting on the edge of the Western Himalaya near the Hindukush range and supports a high biodiversity; pastoralism is the main land use. There have been no previous quantitative ecological studies in this region. This study was undertaken to (i) analyze and describe vegetation using classification and ordination techniques, (ii) identify environmental gradients responsible for plant community distributions and (iii) assess the anthropogenic pressures on the vegetation and identify priorities for conservation. Phytosociological characteristics of species were measured alongside environmental variables. A total of 198 species from 68 families were quantified at 144 stations along 24 transects across an elevation range of 2450–4100m. Correspondence Analysis techniques i.e., Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to determine vegetation–environment relationships. Results show vegetation changes with altitude from moist-cool temperate communities characterized by woody species, to more dry-cold subalpine and alpine herbaceous communities. Plant species diversity is optimal at middle altitudes (2800–3400m); at lower altitudes (2400–2800m) it is reduced by anthropogenic impacts and at higher altitudes (3400–4100m) by shallow soils and high summer grazing pressure. A large number of plant species of conservation concern were identified in the study and an assessment made of the main threats to their survival.

Orchid abundance in hemiboreal forests: stand-scale effects of clear-cutting, green-tree retention, and artificial drainage

The current knowledge on the impact of forest management on plant species of conservation concern is poor. We asked how three basic silvicultural techniques (clear-cutting, green-tree retention, and artificial drainage) affect the abundance of terrestrial orchid species and their communities in Estonia, hemiboreal Europe. Fixed-area, fixed-effort surveys (4 h per 2 ha plot) were used in 29 plot clusters representing five site types, with each cluster including plots of four treatments (old growth, mature managed forest, and cutover with and without live retention trees). Altogether 11 species of orchids were recorded in those 116 plots, with the most complete sets of species in artificially drained plots and mature stands. Five species were widely distributed among treatments and site types, but most site types also hosted shade-tolerant orchids (six species) that characteristically disappeared after timber harvesting. Cutover areas (3–7 years after harvest) hosted no species absent from uncut forest stands, and retention of solitary trees had no effect on orchid abundance over clear-cuts. Modern Estonian forest landscapes appear to support viable populations of many orchids, with rotation ages sufficient for population development of the majority of shade-tolerant species.