Niche-based modelling as a tool for predicting the risk of alien plant invasions at a global scale

Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well‐known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high‐risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility. The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first‐step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted.     

Risk management to prioritise the eradication of new and emerging invasive non-native species

Robust tools are needed to prioritise the management of invasive non-native species (INNS). Risk assessment is commonly used to prioritise INNS, but fails to take into account the feasibility of management. Risk management provides a structured evaluation of management options, but has received little attention to date. We present a risk management scheme to assess the feasibility of eradicating INNS that can be used, in conjunction with existing risk assessment schemes, to support prioritisation. The Non-Native Risk Management scheme (NNRM) can be applied to any predefined area and any taxa. It uses semi-quantitative response and confidence scores to assess seven key criteria: Effectiveness, Practicality, Cost, Impact, Acceptability, Window of opportunity and Likelihood of re-invasion. Scores are elicited using expert judgement, supported by available evidence, and consensus-building methods. We applied the NNRM to forty-one INNS that threaten Great Britain (GB). Thirty-three experts provided scores, with overall feasibility of eradication assessed as ‘very high’ (8 species), ‘high’ (6), ‘medium’ (8), ‘low’ (10) and ‘very low’ (9). The feasibility of eradicating terrestrial species was higher than aquatic species. Lotic freshwater and marine species scored particularly low. Combining risk management and existing risk assessment scores identified six established species as priorities for eradication. A further six species that are not yet established were identified as priorities for eradication on arrival as part of contingency planning. The NNRM is one of the first INNS risk management schemes that can be used with existing risk assessments to prioritise INNS eradication in any area.     

Predicting introduction, establishment and potential impacts of smallmouth bass

Aim The introduction of non‐indigenous species has resulted in wide‐ranging ecological and economic impacts. Predictive modelling of the introduction and establishment of non‐indigenous species is imperative to identify areas at high risk of invasion to effectively manage non‐indigenous species and conserve native populations. Smallmouth bass (Micropterus dolomieu), a warm water fish species native to central North America has negatively impacted native fish communities, including cyprinids and salmonid populations, as a result of intentional introductions. We predicted the introduction risk; species establishment based on habitat suitability; identified lakes at high risk of invasion; and finally assessed the consequential impacts on native salmon, trout and cyprinid populations. Location Ontario and British Columbia, Canada. Methods Classification tree and logistic regression models were developed and validated to predict the introduction and establishment of smallmouth bass for thousands of lakes. Results Densely human populated areas and larger lake surface areas successfully identify lakes associated with the introduction of smallmouth bass (introduction model) in British Columbia. Climate, lake morphology and water chemistry variables were the driving environmental parameters to define suitable smallmouth bass habitat (establishment model). A combination of the introduction and establishment model identified 138 lakes that are currently at risk in British Columbia to the introduction and establishment of smallmouth bass. Of these 138 high‐risk lakes, 95% of them contain at least one species of salmon, trout or cyprinid, thereby increasing the potential impact of an invasion by smallmouth bass. Main conclusions Our framework can be applied to other terrestrial and aquatic species to obtain a better understanding of the potential risk posed by a non‐indigenous species to an ecosystem. Furthermore, our methodology can be used to focus management efforts on areas at higher risk (e.g. number of potential releases, more favourable habitats) to control future introductions of non‐indigenous species, thereby conserving native populations.     

Incorporating risk mapping at multiple spatial scales into eradication management plans

The success of pro-active management of invasive plants depends on the ability to rapidly detect invasive populations and individuals. However, the factors important for detection depend on the spatial scale examined. We propose a protocol for developing risk maps at national, landscape, and local scales to improve detection rates of invasive plant species. We test this approach in the context of developing an eradication plan for the invasive tree Acacia stricta in South Africa. At a national scale we used bioclimatic models coupled with the most likely sites of introduction (i.e. forestry nursery plantations) to identify areas where national-scale surveillance should be focussed. At the landscape and local scales we correlated the presence of A. stricta populations to various attributes. Regional populations were found in forestry plantations only, and mostly on highly used graded roads along which seeds are spread by road maintenance vehicles. Locally, previously recorded plant localities accurately predicted individuals in subsequent surveys. Using these variables, we produced a map of high-risk areas that facilitated targeted searches—which reduced the required search effort by ca. 83 %—and developed recommendations for site-specific surveying. With the high visibility of plants, and relatively small seed banks, long-term annual clearing should achieve eradication. We propose that such multi-scale risk mapping is valuable for prioritising management and surveillance efforts, though caution that the approach is correlative and so it does not represent all the sites that can be invaded.     

Prioritizing plant eradication targets by re-framing the project prioritization protocol (PPP) for use in biosecurity applications

The eradication of newly detected alien plant species is often prescribed, but rarely successful. Eradication programs fail for many reasons, however, for eradication to remain a cost-efficient management option it is clear that good decisions must be made at the outset. Here we re-frame the project prioritization protocol (PPP), a tool widely used in conservation biology, for use with the metrics typically used by a biosecurity agency. We then use existing methods to estimate the cost-efficiency of eradicating 50 hypothetical species incursions and compare the reduction in weed risk achieved by allocating resources using the PPP framework with the allocation based on risk ranking. By allocating resources to plant eradication programs using the PPP our analysis indicated that it is possible to improve the return on public expenditure by 25% compared to investing based solely on weed risk assessment scores. We also demonstrate how the cost-efficiency of the overall portfolio is influenced by the choice of planning horizon; including the decline in overall portfolio performance that arises when attempting to eradicate individual species too quickly. Finally, we discuss the logistical benefits to a management agency that arise from the use of a generic overarching framework such as the PPP. We believe that the PPP has considerable potential for use in biosecurity and can help focus attention on those species where management can make the biggest difference.     

An Internet‐based platform for the estimation of outcrossing potential between cultivated and Chilean vascular plants

A national‐scale study of outcrossing potential within Chilean vascular flora was conducted using an upgraded algorithm, which adds parameters such as pollinator agents, climate, and geographic conditions. Datasets were organized and linked in a Web platform ( www.flujogenico.cl ), in which the development of a total outcrossing potential (TOP) predictor was formulated. The TOP predictor is the engine in the Web platform, which models the effect of a type of agricultural practice on others (coexistence calculation mode) and on the environment (biodiversity calculation mode). The scale for TOP results uses quintiles in order to define outcrossing potential between species as “very low,” “low,” “medium,” “high,” or “very high.” In a coexistence analysis considering 256 species (207 genera), the 10 highest TOP values were for genera Citrus, Prunus, Trifolium, Brassica, Allium, Eucalyptus, Cucurbita, Solanum, Lollium, and Lotus. The highest TOP for species in this analysis fell at “high” potential, 4.9% of the determined values. In biodiversity mode, seven out of 256 cultivated species (2.7%) were native, and 249 (97.3%) corresponded to introduced species. The highest TOP was obtained in the genera Senecio, Calceolaria, Viola, Solanum, Poa, Alstroemeria, Valeriana, Vicia, Atriplex, and Campanula, showing “high” potential in 4.9% of the values. On the other hand, 137 genetically modified species, including the commercial and pre‐commercial developments, were included and represented 100 genera. Among these, 22 genera had relatives (i.e., members of the same genus) in the native/introduced group. The genera with the highest number of native/introduced relatives ranged from one (Ipomea, Limonium, Carica, Potentilla, Lotus, Castanea, and Daucus) to 66 species (Solanum). The highest TOP was obtained when the same species were coincident in both groups, such as for Carica chilensis, Prosopis tamarugo, and Solanum tuberosum. Results are discussed from the perspective of assessing the possible impact of cultivated species on Chilean flora biodiversity. The TOP predictor ( http://epc.agroinformatica.cl/ ) is useful in the context of environmental risk assessment.     

Quantifying targets to manage invasion risk: light gradients dominate the early regeneration niche of naturalized and pre-commercial Miscanthus populations

Prospective bioenergy crops have caused concern about their invasive potential because they often share characteristics with known invasive species. Studies that examine the factors that limit regeneration of these crop species will be crucial for identifying vulnerable habitats and devising management strategies to reduce the likelihood of escape from cultivation. Using a response surface design, we investigated the influence of light availability, soil moisture, and litter cover on recruitment and establishment of a potential biofuel cultivar of Miscanthus as well as an invasive congener. Responses were similar for the two plant types. Light availability had a strong influence on seedling success at both stages, though light limitation prevented establishment only at the lowest light level. Although variation in recruitment rates was low within plant types, establishment varied extensively in response to different light conditions. Low variation in Miscanthus seedling recruitment that led to establishment of a seedling bank under a range of light intensities may facilitate a “sit and wait” situation that raises the likelihood of successful escapes. Therefore, management efforts that restrict seed movement and increase light competition for seedlings will be important for lowering invasion risk. As deliberate introductions of bioenergy crops increase, ecological studies that quantify conditions required for successful escapes will be key to helping agronomists and managers mitigate the risk of unintended invasions.     

Prediction of climate warming impacts on plant species could be more complex than expected. Evidence from a case study in the Himalaya

Many studies have investigated the possible impact of climate change on the distributions of plant species. In the present study, we test whether the concept of potential distribution is able to effectively predict the impact of climate warming on plant species.Using spatial simulation models, we related the actual (current species distribution), potential (modelled distribution assuming unlimited dispersal) and predicted (modelled distribution accounting for wind-limited seed dispersal) distributions of two plant species under several warming scenarios in the Sagarmatha National Park (Nepal). We found that the two predicted distributions were, respectively, seven and nine times smaller than the potential ones. Under a +3 °C scenario, both species would likely lose their actual and predicted distributions, while their potential distributions would remain partially safe. Our results emphasize that the predicted distributions of plant species may diverge to a great extent from their potential distributions, particularly in mountain areas, and predictions of species preservation in the face of climate warming based on the potential distributions of plant species are at risk of producing overoptimistic projections.We conclude that the concept of potential distribution is likely to lead to limited or inefficacious conservation of plant species due to its excessively optimistic projections of species preservation. More robust strategies should utilize concepts such as “optimal reintroduction”, which maximizes the benefit–cost ratio of conservation activities by limiting reintroduction efforts to suitable areas that could not otherwise be reached by a species; moreover, such strategies maximize the probability of species establishment by excluding areas that will be endangered under future climate scenarios.     

Application of the Wagner's Parsimony Method in fossil plant assemblages from the Cretaceous of Europe

Wagner's Parsimony Method, a grouping method used in phylogeny and synecology, is applied for the first time to taxon lists of fossil plant assemblages from the Albian–Cenomanian of Europe. When compared to a “classical” Correspondence Analysis, WPM allows for a higher resolution, using taxa named in “cf.” or “aff.” and points out both clusters and gradients. WPM results in a tree in which localities order according to their species content and minimizes the number of changes of character states (presence/absence), whereas Correspondence Analysis plots the localities along axes and maximizes the inertia (“variance” explaining most differences between localities). Close relationships exist between the plant palaeobiocenoses and palaeobiotopes, the latter being inferred from taphonomical data (especially the salinity and the clastic size). The space/time working scale can be very fine, up to the landscape ecology level.     

Climate change and biological invasions: evidence,expectations, and response options

A changing climate may directly or indirectly influence biological invasions by altering the likelihood of introduction or establishment, as well as modifying the geographic range, environmental impacts, economic costs or management of alien species. A comprehensive assessment of empirical and theoretical evidence identified how each of these processes is likely to be shaped by climate change for alien plants, animals and pathogens in terrestrial, freshwater and marine environments of Great Britain. The strongest contemporary evidence for the potential role of climate change in the establishment of new alien species is for terrestrial arthropods, as a result of their ectothermic physiology, often high dispersal rate and their strong association with trade as well as commensal relationships with human environments. By contrast, there is little empirical support for higher temperatures increasing the rate of alien plant establishment due to the stronger effects of residence time and propagule pressure. The magnitude of any direct climate effect on the number of new alien species will be small relative to human‐assisted introductions driven by socioeconomic factors. Casual alien species (sleepers) whose population persistence is limited by climate are expected to exhibit greater rates of establishment under climate change assuming that propagule pressure remains at least at current levels. Surveillance and management targeting sleeper pests and diseases may be the most cost‐effective option to reduce future impacts under climate change. Most established alien species will increase their distribution range in Great Britain over the next century. However, such range increases are very likely be the result of natural expansion of populations that have yet to reach equilibrium with their environment, rather than a direct consequence of climate change. To assess the potential realised range of alien species will require a spatially explicit approach that not only integrates bioclimatic suitability and population‐level demographic rates but also simulation of landscape‐level processes (e.g. dispersal, land‐use change, host/habitat distribution, non‐climatic edaphic constraints). In terms of invasive alien species that have known economic or biodiversity impacts, the taxa that are likely to be the most responsive are plant pathogens and insect pests of agricultural crops. However, the extent to which climate adaptation strategies lead to new crops, altered rotations, and different farming practices (e.g. irrigation, fertilization) will all shape the potential agricultural impacts of alien species. The greatest uncertainty in the effects of climate change on biological invasions exists with identifying the future character of new species introductions and predicting ecosystem impacts. Two complementary strategies may work under these conditions of high uncertainty: (i) prioritise ecosystems in terms of their perceived vulnerability to climate change and prevent ingress or expansion of alien species therein that may exacerbate problems; (ii) target those ecosystem already threatened by alien species and implement management to prevent the situation deteriorating under climate change.     

Differences in species richness and life-history traits between grazed and abandoned grasslands in southern Sweden

Disturbance has profound effects on plant community composition. This paper deals with the influence of grazing on species richness and proportions of life‐history attributes of grassland vegetation at six spatial scales (0.001–1000 m²) in two provinces of southern Sweden. The study comprised 33 dry grassland sites, including 22 grazed and 11 abandoned localities, and 28 sites of coastal brackish meadows, divided into five management types (from “heavily grazed” to “abandoned since long time”).
In general grazed sites were species‐richer than abandoned sites, especially at small plot sizes. However, there was a steeper increase in species number towards larger plot sizes in the abandoned sites. Heavy grazing in the coastal meadows resulted in a comparatively low number of species, corroborating the intermediate disturbance hypothesis.
The analysis of life‐history traits indicated the importance of taxonomic group, canopy structure, height, regenerative strategy and, in particular, life form. Leaf anatomy and seed dispersal seemed to be less important. The responses to grazing as regards species traits differed somewhat between grassland types. Grazed sites generally had high proportions of legumes, therophytes, species with basal position of leaves and with regeneration by means of a persistent seed bank. Abandonment of grazing favoured monocots, geophytes, species with vegetative regeneration and (partly) leafy canopy structure. Some differences between grazed and abandoned sites were confined to either the smallest or largest plot sizes, indicating different responses of matrix and interstitial species. Various positive associations (attribute syndromes) or negative associations between individual traits were identified. There was, for example, a positive link between the attributes “geophytes” and “ability of vegetative regeneration”. The recognition of such links is important to avoid misinterpreting certain attributes as functional adaptations to grazing while they are only positively correlated to other attributes of larger significance.     

Monitoring and modeling the invasion of the fast spreading alien Senecio inaequidens DC. in an alpine region

We modeled the distribution of the South African alien Senecio inaequidens DC. in the Aosta Valley, Western Italian Alps, using data extracted from the Regional floristic database and from an intensive field survey carried out in years 2009–2010. The aims of the work were (1) to evaluate whether the species is in the introduction, colonization, or establishment stage of invasion, (2) to detect the environmental factors that drive the invasion process, and (3) to highlight the potential range of distribution of the alien species. The modeling framework was a stepwise generalized linear model (GLM), using gridded presence/absence data and environmental predictors such as topography, climate, land use, and anthropogenic and natural disturbances. GLM were fit both with and without an additional independent variable to take into account current dispersal limitations. S. inaequidens displayed a very fast spread in the Aosta Valley in the years 1990–2010. The species was positively associated with roads and rivers, southern slopes, and negatively with elevation. However, it was found at an elevation of 1600 m, showing the ability to reach higher elevations than those observed for other invasive alien species, and confirming to be pre-adapted to mountain conditions. The difference between the species distribution models, with and without dispersal constraints, suggested that the availability of seed sources still limits the potential distribution of the species, rather than the environmental variables, and that the realized regional niche differs to a great extent from the equilibrium niche. When limitations to the seed source cease (i.e., in the establishment stage), the species will likely invade large areas that are currently characterized by pastures and grasslands with native species of high agricultural importance. The invasion of S. inaequidens should therefore be considered a serious threat, due to its potential to invade mountain regions, and in particular to colonize habitats used for grazing and forage, thus leading to a high risk for cattle and human health. We discuss the relevance of the results both concerning communication with the public and to support local eradication and control activities. The inclusion of S. inaequidens in the “black list” of the regional law for the conservation of alpine flora (L.R. 45/2009) will help to transfer the information and support invasion control, in particular at medium elevations.     

Impacts of rodent eradication on seed predation and plant community biomass on a tropical atoll

Invasive rodent eradications are frequently undertaken to curb island biodiversity loss. However, the breadth of rodents’ ecological impact, even after eradication, is not always fully recognized. For example, the most widespread invasive rodent, the black rat (Rattus rattus), while omnivorous, eats predominantly seeds and fruit. Yet, the effects of seed predation release after eradication on plant communities and ecological functions are not well understood, posing a gap for island restoration. We examined the role of seed predation release following black rat eradication in changes to tree composition and aboveground biomass across an islet network (Palmyra Atoll) in the Central Pacific. We conducted repeated surveys of seed, juvenile, and adult tree biomass and survival in permanent vegetation plots before and after the eradication of rats. We observed a 95% reduction in seed predation for an introduced, previously cultivated tree population (Cocos nucifera). Juvenile tree biomass of all species increased 14‐fold, with C. nucifera increasing the most, suggesting that eradication increased this tree's competitive advantage. Indeed, based on stage‐structured demographic models, rat eradication led to a 10% increase in C. nucifera population growth rate. The effect of invasive rodent seed predation varies considerably among the plant species in a community and can shift competitive dynamics, sometimes in favor of invasive plants. These bottom‐up effects should be considered in evaluating the costs and benefits of eradication. Documenting the variation in invasive rodent diet items, along with long‐term surveys, can help prioritize island eradications where restoration is most likely to be successful.     

Phylogenetic comparative methods: Harnessing the power of species diversity to investigate welfare issues in captive wild animals

This paper reviews a way of investigating health and welfare problems in captive wild animals (e.g., those in zoos, aviaries, aquaria, or aquaculture systems) that has great potential, but to date has been little used: systematically comparing species with few or no health and welfare issues to those more prone to problems. Doing so empirically pinpoints species‐typical welfare risk and protective factors (such as aspects of their natural behavioral biology): information which can then be used to help prevent or remedy problems by suggesting new ways to improve housing and husbandry, and by identifying species intrinsically best suited to captivity. We provide a detailed, step‐by‐step “how to” guide for researchers interested in using these techniques, including guidance on how to statistically control for the inherent similarities shared by related species: an important concern because simple, cross‐species comparisons that do not do this may well fail to meet statistical assumptions of non‐independence. The few relevant studies that have investigated captive wild animals’ welfare problems using this method are described. Overall, such approaches reap value from the great number and diversity of species held in captivity (e.g., the many thousands of species held in zoos); can yield new insights from existing data and published results; render previously intractable welfare questions (such as “do birds need to fly?” or “do Carnivora need to hunt?”) amenable to study; and generate evidence‐based principles for integrating animal welfare into collection planning.     

EVIDENCE FOR IMPACTS OF NONINDIGENOUS MACROALGAE: A META‐ANALYSIS OF EXPERIMENTAL FIELD STUDIES1

Invasions by nonindigenous macroalgal species (NIMS) potentially cause severe impacts on native species. We conducted a meta‐analysis of 18 field‐based manipulative experiments to quantify the direction and magnitude of impacts (Hedges effect size d, hereafter ES). We found significant small‐to‐medium negative effects on “macrophyte abundance” (cover, biomass of native taxa; ES_cumulative = ?0.30) and medium‐to‐large negative effects on “macrophyte assemblages” (richness, diversity, total abundance; ES_cumulative = ?0.70). In contrast, ES_cumulative were not significant for “macrophyte processes” (growth, mortality; ES_cumulative = ?0.39), “animal abundance” (densities; ES_cumulative = ?0.13), or “animal assemblages” (richness, diversity; ES_cumulative = 0.75). The nonsignificant effect sizes were characterized by low sample sizes and should be interpreted with caution. Three study‐specific effect sizes were particularly large (cumulative are likely biased toward larger effects because only the most conspicuous NIMS have been tested and because nonsignificant results are less likely to be published. To better understand the impacts of NIMS, more manipulative experiments are needed, testing more species and under contrasting environmental conditions. Future studies should include procedural control treatments and report the abundance of the NIMS to avoid ambiguous interpretations. In conclusion, current experimental evidence shows that NIMS have, on average, small‐to‐large negative impacts on native plant species and assemblages. It is possible that these effects can result in severe consequences when accumulated over long time periods and large spatial scales.     

No species is an island: testing the effects of biotic interactions on models of avian niche occupation

Traditionally, the niche of a species is described as a hypothetical 3D space, constituted by well‐known biotic interactions (e.g. predation, competition, trophic relationships, resource–consumer interactions, etc.) and various abiotic environmental factors. Species distribution models (SDMs), also called “niche models” and often used to predict wildlife distribution at landscape scale, are typically constructed using abiotic factors with biotic interactions generally been ignored. Here, we compared the goodness of fit of SDMs for red‐backed shrike Lanius collurio in farmlands of Western Poland, using both the classical approach (modeled only on environmental variables) and the approach which included also other potentially associated bird species. The potential associations among species were derived from the relevant ecological literature and by a correlation matrix of occurrences. Our findings highlight the importance of including heterospecific interactions in improving our understanding of niche occupation for bird species. We suggest that suite of measures currently used to quantify realized species niches could be improved by also considering the occurrence of certain associated species. Then, an hypothetical “species 1” can use the occurrence of a successfully established individual of “species 2” as indicator or “trace” of the location of available suitable habitat to breed. We hypothesize this kind of biotic interaction as the “heterospecific trace effect” (HTE): an interaction based on the availability and use of “public information” provided by individuals from different species. Finally, we discuss about the incomes of biotic interactions for enhancing the predictive capacities on species distribution models.     

Measuring floristic homogenization by non-native plants in North America

Aim To determine if non‐native plant species are homogenizing species composition among widely dispersed plant communities. Location Twenty localities in North America. Methods Species lists among localities were compared to measure the influence of non‐native species richness at each locality on the Jaccard Index (JI) of similarity between localities. Results After removing the effects of distance, because shared native species decreased with distance, three (nonexclusive) lines of evidence indicate that non‐native species promote homogenization. First, pairs of sites with a high combined total of non‐native species tend to have higher similarity than those with a low total of non‐natives. Second, for a given distance, more non‐native than native species tended to be shared among localities. Third, whereas most of the site comparisons with high total non‐native richness have a non‐native/native JI ratio greater than 1 (often much greater), only half of the comparisons with low total non‐native richness have a ratio greater than one. Main conclusions These findings provide quantitative support for the widely held, but rarely tested, notion that non‐native species tend to homogenize biological communities because they are more commonly shared among communities. Such testing is important as non‐native species could theoretically have no impact or even reduce homogenization among communities, if non‐native colonizers consist of different species pools.     

Tree population studies in low-diversity forests, Guyana. II. Assessments on the distribution and abundance of non-timber forest products

Comparisons between two forest localities were undertaken to assess the potential availability of non-timber forest products (NTFPs) within the low-diversity forests of Guyana. Information on the abundance and distribution of tree species, and local and national ethnobotanical surveys were used classifying species into five categories (timber, construction, technological, edible and medicinal). A total of 152 species were recorded from the two localities; covering 236 different uses, 33 known commercial timber species and 106 species with potential non-timber product utilization. The most important plant families with the highest number of uses at both localities were Leguminosae (sub-families Caesalpinioideae and Mimosoideae), Arecaceae, Bombacaceae and Chrysobalanaceae, although these families were not the most abundant families at both localities. At both forest localities eight tree species represented over 50% of all the trees. At Kurupukari three species, each with more than three identified NTFPs, represented over 20% of the trees.Potential utilization of NTFPs are discussed in accordance with species richness, tree density, the number of different uses per species, and the percentage of trees represented by each utilizable species. Considering the constraints on the future potential commercialization of NTFPs, two scenarios for the extraction of NTFPs are discussed. Within relatively species-rich forest types the high diversity of products provides potentially viable multiple-species extractionism. In contrast, in low-diversity forest types, typical of the Guiana Shield, one or two NTFP species frequently represent over 50% of the canopy trees, and therefore substantially increase the potential sustainable extraction for single-species harvesting. It is suggested that these low-diversity types of forest are prioritized for conservation on the basis of ensuring future utilization, refuge, of non-timber forest products.     

A GIS‐based decision‐making approach for prioritizing seabird management following predator eradication

Given that 29% of seabird species are threatened with extinction, protecting seabird colonies on offshore islands is a global conservation priority. Seabirds are vulnerable to non‐native predator invasions, which reduce or eliminate colonies. Accordingly, conservation efforts have focused on predator eradication. However, affected populations are often left to passively recover following eradications. Although seabirds are highly mobile, their life history traits such as philopatry can limit passive recolonization of newly predator‐free habitat. In such cases, seabird colonies can potentially be re‐instated with active restoration via chick translocations or social attraction methods, which can be risky and expensive. We used biogeographic and species‐specific behavioral data in the Hauraki Gulf, New Zealand, a global hotspot of seabird diversity and predator eradications, to illustrate the use of geographic information systems multi‐criteria decision analysis to prioritize islands for active seabird restoration. We identified nine islands with low observed passive recovery of seabirds posteradication over a 50‐year timeframe, and classified these as sites where active seabird management could be prioritized. Such spatially explicit tools are flexible, allowing for managers to choose case‐specific criteria such as time, funding, and goals constrained for their conservation needs. Furthermore, this flexibility can also be applied to threatened species management by customizing the decision criteria for individual species' capacity to passively recolonize islands. On islands with complex restoration challenges, decision tools that help island restoration practitioners decide whether active seabird management should be paired with eradication can optimize restoration outcomes and ecosystem recovery.     

Seed mix design and first year management influence multifunctionality and cost‐effectiveness in prairie reconstruction

Agricultural intensification continues to diminish many ecosystem services in the North American Corn Belt. Conservation programs may be able to combat these losses more efficiently by developing initiatives that attempt to balance multiple ecological benefits. In this study, we examine how seed mix design and first year management influence three ecosystem services commonly provided by tallgrass prairie reconstructions (erosion control, weed resistance, and pollinator resources). We established research plots with three seed mixes, with and without first year mowing. The grass‐dominated “Economy” mix had 21 species and a 3:1 grass‐to‐forb seeding ratio. The forb‐dominated “Pollinator” mix had 38 species and a 1:3 grass‐to‐forb seeding ratio. The grass:forb balanced “Diversity” mix, which was designed to resemble regional prairie remnants, had 71 species and a 1:1 grass‐to‐forb ratio. To assess ecosystem services, we measured native stem density, cover, inflorescence production, and floral richness from 2015 to 2018. The Economy mix had high native cover and stem density, but produced few inflorescences and had low floral richness. The Pollinator mix had high inflorescence production and floral richness, but also had high bare ground and weed cover. The Diversity mix had high inflorescence production and floral richness (comparable to the Pollinator mix) and high native cover and stem density (comparable to the Economy mix). First year mowing accelerated native plant establishment and inflorescence production, enhancing the provisioning of ecosystem services during the early stages of a reconstruction. Our results indicate that prairie reconstructions with thoughtfully designed seed mixes can effectively address multiple conservation challenges.