Recovery Of Species Research Articles

Fighting the flames: site-specific effects determine species richness of Australian frogs after fire

Context Fire has played an integral role in regulating patterns of biodiversity for millions of years. However, anthropogenic disturbance and climate change has altered fire activity – driving increases in both fire severity and scale. The effect fire now has on the persistence of biodiversity is poorly known, especially for frogs. Studies examining frog responses to fire usually have small sample sizes, focus upon small geographic areas and are based on low-severity fires, which can mean results are not applicable to high-severity fires, such as those expected under future climate change. Aims Our aims were to examine (1) persistence of frog species, measured by species richness, up to 18 months post-fire, and (2) the effects of varying fire severity on frog species richness and recovery, where we expected higher fire severity to lead to lower species richness after fire. Methods Using large-scale citizen science data from the Australian Museum’s FrogID project, coupled with remotely sensed fire data, we present a spatially and taxonomically broad analysis examining post-fire recovery responses for Australian frog species after the 2019/2020 ‘Black Summer’ bushfires. Key results We reveal no overall decrease in the species richness of Australian frogs both in the short- and long-term post-fire. Furthermore, species richness did not decline with increasing fire severity. Instead, species richness and its response to fire was highly site-specific. Conclusions We provide evidence that widespread and common Australian frog species have persisted post-fire in most sites and concluded that this is potentially due to their ability to shelter from fire adequately and/or La Niña-driven high rainfall offering conditions conducive to breeding activity and persistence. Implications We show how citizen science provides critical data for conservation, especially in response to unprecedented disturbance events, such as the 2019/2020 megafires. Our research also highlights the need for ongoing and targeted scientific monitoring, especially for less common or threatened species.

The end-Cretaceous plant extinction: Heterogeneity, ecosystem transformation, and insights for the future

Abstract The Cretaceous–Paleogene (K–Pg) mass extinction was geologically instantaneous, causing the most drastic extinction rates in Earth’s History. The rapid species losses and environmental destruction from the Chicxulub impact at 66.02 Ma made the K–Pg the most comparable past event to today’s projected “sixth” mass extinction. The extinction famously eliminated major clades of animals and plankton. However, for land plants, losses primarily occurred among species observed in regional studies but left no global trace at the family or major-clade level, leading to questions about whether there was a significant K–Pg plant extinction. We review emerging paleobotanical data from the Americas and argue that the evidence strongly favors profound (generally >50%), geographically heterogeneous species losses and recovery consistent with mass extinction. The heterogeneity appears to reflect several factors, including distance from the impact site and marine and latitudinal buffering of the impact winter. The ensuing transformations have affected all land life, including true angiosperm dominance in the world’s forests, the birth of the hyperdiverse Neotropical rainforest biome, and evolutionary radiations leading to many crown angiosperm clades. Although the worst outcomes are still preventable, the sixth mass extinction could mirror the K–Pg event by eliminating comparable numbers of plant species in a geologic instant, impoverishing and eventually transforming terrestrial ecosystems while having little effect on global plant-family diversity.

Implications of extinction in law: Preventing, declaring and learning from species extinctions

Abstract Biodiversity laws around the world differ, but, at their core, these laws promote the fundamental objective of preventing environmental decline and species extinctions. A variety of legal mechanisms have been implemented in domestic laws around the world to achieve this objective, including protection for habitat, environmental impact assessments and threatened species recovery plans. In many jurisdictions, if these mechanisms fail to protect a species, it may be legally declared extinct, or added to a formal list of those that have been lost. This article examines the conservation purpose and legal implications for laws about extinction. A legal power to recognise a species as extinct has the potential to foster ambition, transparency and rigorous measurement of progress against conservation goals. However, in practice, efforts to prevent extinction are applied selectively. Without an obligation to learn from extinctions, recognition of species extinctions in law may have perverse effects, or no effect at all. This article proposes a conceptual model for the role of law in relation to extinctions, highlighting opportunities to improve legal frameworks to achieve more productive and positive conservation outcomes, even as climate change and other pressures drive many more species towards extinction.

Tragic Moral Conflict in Endangered Species Recovery

Tragic moral conflicts are situations from within which whatever one does—including abstaining from action—will be seriously wrong; even the overall right decision involves violating a moral responsibility. This article offers an account of recovery predicaments, a particular kind of tragic conflict that characterizes the current extinction crisis. Recovery predicaments occur when the human-caused extinction of a species or population cannot be prevented without breaching moral responsibilities to animals by doing violence to or otherwise severely dominating them. Recognizing the harm of acting from within recovery conflicts adds force to appeals for interrogating and dismantling the systems of thinking, valuing, and acting that bring species to the brink of extinction.

Microbial Biofilms for Environmental Bioremediation of Heavy Metals: a Review.

Heavy metal pollution caused due to various industrial and mining activities poses a serious threat to all forms of life in the environment because of the persistence and toxicity of metal ions. Microbial-mediated bioremediation including microbial biofilms has received significant attention as a sustainable tool for heavy metal removal as it is considered safe, effective, and feasible. The biofilm matrix is dynamic, having microbial cells as major components with constantly changing and evolving microenvironments. This review summarizes the bioremediation potential of bacterial biofilms for different metal ions. The composition and mechanism of biofilm formation along with interspecies communication among biofilm-forming bacteria have been discussed. The interaction of biofilm-associated microbes with heavy metals takes place through a variety of mechanisms. These include biosorption and bioaccumulation in which the microbes interact with the metal ions leading to their conversion from a highly toxic form to a less toxic form. Such interactions are facilitated via the negative charge of the extracellular polymeric substances on the surface of the biofilm with the positive charge of the metal ions and the high cell densities and high concentrations of cell-cell signaling molecules within the biofilm matrix. Furthermore, the impact of the anodic and cathodic redox potentials in a bioelectrochemical system (BES) for the reduction, removal, and recovery of numerous heavy metal species provides an interesting insight into the bacterial biofilm-mediated bioelectroremediation process. The review concludes that biofilm-linked bioremediation is a viable option for the mitigation of heavy metal pollution in water and ecosystem recovery.

Assessing Species Boundaries in the Freshwater Snail Family Physidae Using Coalescent-Based Delimitation Methods

A common issue for several freshwater snail families is the fact that, for some genera, the criteria for species delimitation are scarce, subjected to intraspecific and ontogenetic variation, or insufficiently discrete to allow a clear distinction between species. For these genera, the use of molecular approaches is decisive in recognizing valid species. Herein, we applied coalescent methods to delimit evolutionary significant units (ESUs) in Physidae. We used 496 sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene available in GenBank, ascribed to six genera and 25 nominal species, and the algorithms GMYC (General Mixed Yule-Coalescent) with two criteria (single-threshold and multiple-threshold), PTP (Poisson Tree Process), and mPTP (multi-rate Tree Poisson Process). The method that presented the best performance was the mPTP. This method showed a higher frequency of taxonomic species recovery and has delimited a lower number of ESUs (25 ESUs from a dataset attributed to 25 nominal species). Physidae is a family of freshwater snails that presents several issues related to the recognition of species boundaries. Herein, the use of coalescent delimitation methods allowed us to address important taxonomic questions, opening new avenues for future taxonomic research. Our findings have shown that the morphological operational criteria used to delimit several valid species fall within the limits of intraspecific variability, demonstrating taxonomic inflation within this family. Our results also demonstrated the presence of cryptic diversity under the nominal species Physella acuta (Draparnaud, 1805), Beringophysa jennessi (Dall, 1919), Physella pomilia (Conrad, 1834), and Physella gyrina (Say, 1821).

An evidence‐base for developing ambitious yet realistic national biodiversity targets

AbstractBiodiversity targets are a key tool, used at a global and national policy level, to align biodiversity goals, promote conservation action, and recover nature. Yet most biodiversity targets are not met. In England, the government has committed to legally‐binding targets to halt and recover the decline in species abundance by 2030 and 2042. We present evidence from recent population trends of 670 terrestrial animal species (for which abundance time series are available) as a species abundance indicator, together with a synthesis of case studies on species recovery, to assess the degree to which these targets are achievable. The case studies demonstrate that recovery is possible through a range of approaches. The indicator demonstrates that theoretically targets can be achieved by addressing severe declines in a relatively small number of species, as well as creating smaller benefits for many species through landscape‐scale interventions. The fact that multiple pathways exist to achieve the species abundance targets in England presents choices but also raises the possibility that targets might be reached with perverse consequences. We demonstrate that evidence on achievability is a necessary but not sufficient condition for determining what is required to deliver conservation outcomes and restore biodiversity.

In the past 100 years dragonflies declined and recovered by habitat restoration and climate change

The availability of opportunistic dragonfly data in the Netherlands spanning >100 years gave us the opportunity to quantitatively assess long term changes in range size. We estimated changes in the number of occupied 5 km × 5 km sites by applying a modified List Length method, which takes into account changes in observation effort. Trends were assessed for nearly all Dutch dragonfly species and the trends were then summarised in Multi-Species Indicators by taking the geometric mean of the species indices. Overall, dragonflies severely declined in range size between the periods 1850–1950 and 1975–1990. In the period thereafter, strong increases happened, during which many species compensated their earlier losses. The factors driving the changes in dragonflies shifted over time. Until 1975 dragonfly species declined due to deterioration of water systems. After 1975 both climate change and habitat restoration contributed to the recovery of many species. Restoration of dragonfly communities was most successful in running water and least effective in moorland pools.

Roadmap to recovery revealed through the reintroduction of an IUCN Red List species

Reintroductions are powerful tools for tackling biodiversity loss, but the resulting populations can be intrinsically small and vulnerable. It is therefore critical to maximise the number of individuals that are available to contribute to recovery efforts. To address this, we investigated how demographic parameters from a reintroduced population can reveal threats to long-term persistence, inform thresholds for management interventions, and create targets for removing an endangered species from the IUCN Red List. We calculated capture-mark-recapture population estimates for eastern quolls (Dasyurus viverrinus) which had been reintroduced to a fenced reserve in the Australian Capital Territory. We then incorporated the resulting demographic parameters into population viability analyses (PVAs) to estimate probabilities of persistence under several scenarios, including supplementations and harvests (removal of individuals for translocation to other locations). After determining sustainable harvest rates, we then ‘back-cast’ the population size and occupancy area required to remove the species from the IUCN Red List within 10 years. Our demographic results indicated high mean apparent survival (90% ± 5), and PVAs revealed the probability of persistence over a 50-year time horizon was 50.5% with no interventions, 0% when the population was harvested of > 6 individuals, and 100% if harvests ≤ 54 juveniles were combined with an annual supplementation of ten maternal females (with ≤ 6 young each). Based on this model, a total harvest area of 413 km2 and an occupancy area of 437 km2 would be needed to recover the species within 10 years (i.e., 90 similar fenced reserves, not accounting for edge effects). Due to the inherent difficulty in securing large areas for species recovery, we see these ambitious targets as a call to create coordinated and collaborative sanctuary networks where species can be managed as a metapopulation across multiple sites. By taking advantage of a rapid life history and harvesting the ‘doomed surplus’, managers can achieve their stretch goals for species recovery in the long term.

A metabarcoding framework for wild bee assessment in Luxembourg

Wild bees are crucial organisms for terrestrial environments. Their ongoing decline could cause irreparable damage to ecosystem services vital to plant reproduction and human food production. The importance of taking swift action to prevent further declines is widely acknowledged, but the current deficit of reliable taxonomic information complicates the development of efficient conservation strategies targeting wild bees. DNA metabarcoding can help to improve this situation by providing rapid and standardized mass identification. This technique allows the analysis of large numbers of specimens without the need for specialized taxonomic knowledge by matching high-throughput sequencing reads against public DNA barcode reference libraries. However, the validation of this approach for wild bees requires the evaluation of potential error sources on a regional scale. Here we analyzed the effects of three potential error sources on a metabarcoding pipeline customized for the wild bee fauna of Luxembourg. In an in silico study, we checked the completeness of the BOLD reference library for 349 species found in the country, the correspondence between molecular and morphological species delimitation for these taxa, and the amplification efficiency of three commonly used metabarcoding primer pairs (mlCOlintF/HCO2198, LepF1/MLepF1-Rev and BF2/BR2). The detection power of the pipeline was evaluated based on the species recovery rates from mock communities of known composition under variable DNA concentration treatments. The reference barcode library evaluation results show that 97% of the species have at least a single barcode in BOLD Systems (minimal length 196 bp) and that 85% of species have ≥ 5 barcodes in the public domain. The mlCOlintF/HCO2198 target fragment presented the highest coverage (77.94% of the species with full barcode sequences), followed by the target fragments of LepF1/MLepF1-Rev (77.65%) and BF2/BR2 (68.48%). Only 60% of the morphospecies presented a complete coverage of the prominent Folmer region (658 bp). The in silico amplification efficiency analysis shows that the BF2/BR2 primer pair has the best-predicted amplification performance, but none of the primer combinations evaluated can be expected to efficiently amplify all local wild bee genera. Finally, all species detection rates in the mock communities, except for the sample with the most discrepant DNA concentrations, were above 97%, with no significant differences found among treatments. These results indicate that the detection capacity of the pipeline is robust enough to be used for the reliable assessment of local wild bee biodiversity, even if species from various size categories are pooled together. Primer bias has a major effect on species detection, which can be acknowledged with a preliminary assessment of primer-template mismatch and sophisticated methodological designs (e.g. mock community controls, replicates). Overall, the metabarcoding pipeline here described provides a suitable tool for quick and reliable taxonomic identification of the regional wild bee fauna to aid conservation initiatives in Luxembourg – and beyond.

Long-term recovery of Mexican spotted owl nesting habitat after fire in the Lincoln National Forest, New Mexico

BackgroundDry mixed-conifer forests of the southwestern United States are experiencing rapid, anthropogenically driven fire regime change. Prior to the Euro-American settlement, most of these forests experienced frequent surface fires but are now vulnerable to uncharacteristically large, high-severity fires. Fire directly influences the structure and composition of these forests and, in turn, the wildlife that inhabit them. Changing fire regimes result in a certain decline of some species and uncertain consequences for others. The Mexican spotted owl (Strix occidentalis lucida) is a federally listed threatened species of particular note in southwestern mixed-conifer forests. High-severity fire is cited as the owl’s primary threat in the revised species recovery plan, but uncertainties surround the impacts of high-severity fire on the habitat of the threatened owl, particularly across a timeframe longer than a few years. Our objective was to explore the long-term (100-year) effects of fire severity on elements of forest structure vital for Mexican spotted owl nesting. We quantified structural attributes for nest/roost habitat across mixed-conifer forests that burned at varying severity levels and time periods in the last century. We then examined the drivers of structural attributes by detecting statistical differences between severity classes and time periods through permutational multivariate analysis of variance.ResultsHigh-severity fire has the strongest deleterious impact on elements of forest structure (total basal area, percent medium tree basal area, percent large tree basal area, large tree density, and canopy cover) vital to Mexican spotted owl nesting, and although the structural differences between severity classes diminish with time, it took ≥ 80–100 years to reach the structural conditions desired for Mexican spotted owl nesting after stand-replacing fires. The most important attribute measured, canopy cover, required 90–100 years after high-severity fires to reach levels most suitable for Mexican spotted owls in the Lincoln National Forest.ConclusionsAs fires increase in frequency, severity, and size compared to the last century, the Lincoln National Forest is projected to face an overall decrease in the structural conditions needed for Mexican spotted owl nesting habitat in this region. Short intervals between uncharacteristically high-severity fires in particular pose an imminent threat to nesting habitat.

Incorporating Evidence into Collaborative Ecosystem Restoration: A Content Analysis of Bibliographic References and their Use in Salmon Recovery Plans.

Collaborative environmental management draws on a wide range of information, from a variety of stakeholders, to inform policy. Scientific information is particularly relevant for ecosystem restoration plans, such as those created for recovering species on the brink of extinction. This study examines use of evidence in salmon recovery plans in Puget Sound, USA. Across 12 plans, coders characterized 1104 references to identify their source, recency, domain, and context. Subsequently, 11 plans were analyzed in-depth to identify how each reference was used to support particular kinds of claims. Results indicate the most frequent source of information cited in salmon recovery plans is government agencies, especially from national and state governments, followed by peer reviewed journal articles and scientific books. Journal articles come predominantly from high impact (top quartile) journals, although these articles are on average 15 years old. Sources are almost exclusively from the domain of natural sciences (97%), with just 1% social sciences and 2% non-scientific. More references come from beyond than within the local watershed. Different reference sources are used to support different kinds of claims, with government agency sources positively associated with claims about species status/trends, and peer reviewed journal articles positively associated with claims about causes of species decline. Overall, the lack of social science references, and lack of references to support claims about levels of community support, reduce managers' abilities to incorporate features of social systems into species recovery planning.

Threat-abatement framework confirms habitat retention and invasive species management are critical to conserve Australia's threatened species

Earth's extinction crisis is escalating, and threat classification schemes are increasingly important for assessing the prominent drivers and threats causing species declines. However, a complementary framework for assessing the conservation responses needed to abate these threatening processes is lacking. Here we draw on expert knowledge and published literature to develop a threat-abatement framework which groups threats based on the shared conservation goal of the actions needed to abate their impact and apply it to 1532 threatened species across the Australian continent. Our analysis shows that the most important conservation actions across Australia are to retain and restore habitat, due to the threats posed by habitat destruction and degradation (via logging, mining, urbanisation, roads, and agriculture) to 86 % of Australia's threatened species. Most species also require the effective control of invasive species and diseases (82 %) and improved fire management (66 %). Countering individual threats will not be enough to support species survival or recovery, because almost all species (89 %) require multiple, integrated management responses to redress their threats. Our threat abatement framework enables rapid identification of broad conservation responses to aid recovery of threatened species and can be applied in other regions, scales and contexts.

Grazing capacity change on a small Mediterranean-type South African offshore island following the control of invasive alien European rabbits (Oryctolagus cuniculus)

Invasive alien species (IAS) are one of the most important factors driving extinction rates worldwide. Among the IAS, the impacts of introduced mammals on native biodiversity are most severe, with the European rabbit (Oryctolagus cuniculus) being the most problematic. Globally, European rabbits have been introduced to five continents and more than 800 islands or island groups where they are a threat to biodiversity and human livelihoods. The impacts of European rabbits on biodiversity and human livelihoods have been extensively studied across the globe. However, some regions of the world, such as the offshore islands along Africa’s southern coast, have been sparsely studied. In this study, we monitored change in grazing capacity on a South African offshore island, Robben Island, following an attempt to eradicate European rabbits between 2008 and 2009. Grazing capacity on the island increased following rabbit control, driven by the recovery of palatable plant species in response to release from herbivory. There was no change in grazing capacity at sites under Eucalyptus plantations because of the inhibitory effects of the alien trees on understory vegetation dynamics. We believe that grazing capacity changes on Robben Island are indicative of potential vegetation changes on other southern African offshore islands.

Fire and tree species diversity in tropical peat swamp forests

Tropical peat swamp forests contain diverse plant communities that support many endangered flora and fauna species. These forests are increasingly threatened by disturbances such as drainage, logging, and subsequent fire, yet little is known about tree species recovery from these threats.Tree species richness and diversity were measured in peat swamp forests of Central Borneo regenerating naturally after fires from 139 chronosequence plots. Our findings indicated that two to three decades after fire, similar levels of richness and diversity to relatively undisturbed reference forest are reached within sites. However, when averaged across landscapes our modelling shows that fires of average frequency of 50 years, or even 100 years, can substantially suppress tree species richness and diversity. Thus, even rare fires can reduce the species richness and diversity of tropical peat swamp forests.Two groups of tree species drove the difference in richness and diversity between disturbed and reference forests: ‘decreasers’, occupying recently burnt forest and declining with fire exclusion, and ‘increasers’, that were only present in less disturbed forests and absent or rare in recently burnt forests. The decreasers were more common than the increasers.We conclude that peat swamp forests can recover adequately from fires through natural regeneration, and it is possible that artificial planting may speed up this process. Where possible, excluding fire from tropical peat forests will help to maintain the diversity of these threatened ecosystems and promote their recovery.

Resilience and Resistance Framework Predicts Regional Vegetation Responses to Shrub Reduction Treatments in the Sagebrush Ecosystem

The concepts of ecosystem resilience and resistance (R&R) are being widely used in management planning for the big-sagebrush ecosystem of the western United States. Soil temperature and moisture regimes have been used to map geographic areas that are expected to have high, moderate, or low resilience (recovery of perennial species after disturbance) and resistance (to the spread of invasive annual grasses, most often Bromus tectorum L. or cheatgrass). While the theory underlying this framework is well developed, there have been few empirical tests of the map's utility in predicting on-the-ground management outcomes. We used data from 51 sites in Utah to relate R&R level to changes in plant cover after disturbances, using effect size analyses that standardized the magnitude of postdisturbance change (relative to predisturbance levels) across sites. Sites had been treated mechanically to reduce shrub cover or burned, and most sites were seeded. Perennial grass cover, which included native and non-native species due to the seed mixes used, increased in all R&R classes relative to predisturbance levels, but this increase was greatest at High R&R sites. Perennial forb cover increased only in the High R&R sites and decreased in Low R&R sites. Sagebrush shrub cover decreased across all R&R levels but showed evidence of recovery at High and Moderate R&R sites. These results indicate that outcomes across different disturbance types were generally in line with expectations based on the R&R map. Annual grass cover increased slightly at High and Moderate R&R sites but decreased in the Low R&R sites. These annual grass results illustrate that local site characteristics, and history may be more important factors than broad-scale soil moisture-temperature regime classifications in some cases. Nonetheless, our results overall indicate that the R&R map can be a useful tool for predicting the general outcomes of management actions in the sagebrush ecosystem.

Scaling up restoration efforts by simulating the effects of fire to circumvent prescribed burns when preparing restoration sites in South African fynbos ecosystems

AbstractThe method of clearing alien species and the nature of the soil seedbank influence the quality of restoration outcomes, particularly in fire‐prone ecosystems heavily invaded with fire‐adapted alien species. One of the challenges encountered is reducing the likelihood of reinvasions when the invading species are equally responsive to restoration treatments. By simulating the fire effects that are required to regenerate native vegetation, the study tested whether the recovery of the native species could be initiated without conducting a prescribed ecological burn. In a case study of South African Cape Flats Sand Fynbos with a heavy invasion ofAcacia saligna, the felled acacia were stacked into brush piles, with the litter raked off from the sowing areas and the collected seeds were pre‐treated for germination. Despite the lack of a fire, the sowing of pre‐treated seeds on raked plots led to good recovery of native vegetation over time. This was indicated by the recovery of higher density, cover and richness of native species in sown plots compared with unsown treatments. However, the recovery of native species had not approached the vegetation structure comparable to a reference site after 2 years; that is, only partial fynbos structure was recovered. The recruitment of acacia was less dense without fire, as hypothesised, and independent of treatment. However, over time, control plots had higher acacia cover than other treatments. Despite this sparse recruitment of acacia, the acacia seedbank decreased naturally to about 50% of the initial size over 2 years in control plots. Raking off litter during site preparation removed 50% of the acacia seedbank which decreased slightly thereafter. Consequently, the residual acacia seedbank was relatively similar across treatments after 2 and a half years. In conclusion, circumventing prescribed burns in heavily degraded fynbos ecosystems is a scalable restoration strategy, as recruitment of alien acacia was minimized, its seedbank declined significantly, and good native cover developed after clearing and sowing.

Tuning charge density in tethered electrolyte active-layer membranes for enhanced ion-ion selectivity

Efforts toward developing membranes for aqueous separations beyond desalination have intensified, in attempts to achieve zero liquid discharge and a circular economy. Treatment of unconventional wastewaters and brines as well as recovery of valuable species require separation of solutes and ions. Recently, tethered electrolyte active-layer membranes (TEAMs) with dense ionizable brush polymers grafted from cellulose ultrafiltration supports were introduced as a robust, highly controllable membrane platform for these aqueous separations. In this study, we investigate crosslinking of single-block TEAMs to increase the effective charge density and coverage of pores by the active layer, and to possibly tap into size-based exclusion mechanisms. We also determine if crosslinking multiblock TEAMs comprising block copolymers of both negative and positive charge can better align blocks, thereby improving ion rejection. Single-block TEAMs with relatively short crosslinkers proved to have the highest divalent co-ion rejection in dilute solutions, at ∼85–95%. NaCl was rejected ∼55 and 80% by crosslinked negatively- and positively-charged TEAMs, respectively. Anion monovalent selectivity, Cl−/SO42−, was as high as ∼25 for negative TEAMs, while the maximum Na+/Ca2+ ratio achieved by positive TEAMs was ∼9.5. This work reinforces the value of ultrathin brush active-layer membranes and TEAMs as important tools to understand fundamental transport through membranes and better control synthesis for targeted selectivity.

Addressing Detection Uncertainty in Bombus affinis (Hymenoptera: Apidae) Surveys Can Improve Inferences Made From Monitoring.

The U.S. Fish and Wildlife Service developed national guidelines to track species recovery of the endangered rusty patched bumble bee [Bombus affinis Cresson (Hymenoptera: Apidae)] and to investigate changes in species occupancy across space and time. As with other native bee monitoring efforts, managers have specifically acknowledged the need to address species detection uncertainty and determine the sampling effort required to infer species absence within sites. We used single-season, single-species occupancy models fit to field data collected in four states to estimate imperfect detection of B. affinis and to determine the survey effort required to achieve high confidence of species detection. Our analysis revealed a precipitous, seasonal, decline in B. affinis detection probability throughout the July through September sampling window in 2021. We estimated that six, 30-min surveys conducted in early July are required to achieve a 95% cumulative detection probability, whereas >10 surveys would be required in early August to achieve the same level of confidence. Our analysis also showed B. affinis was less likely to be detected during hot and humid days and at patches of reduced habitat quality. Bombus affinis was frequently observed on Monarda fistulosa (Lamiales: Lamiaceae), followed by [Pycnanthemum virginianum Rob. and Fernald (Lamiales: Lamiaceae)], Eutrochium maculatum Lamont (Asterales: Asteraceae), and Veronicastrum virginicum Farw. (Lamiales: Plantaginaceae). Although our research is focused on B. affinis, it is relevant for monitoring other bumble bees of conservation concern, such as B. occidentalis Greene (Hymenoptera: Apidae) and B. terricola Kirby (Hymenoptera: Apidae) for which monitoring efforts have been recently initiated and occupancy is a variable of conservation interest.

Does hatchery rearing of lake trout affect their reproductive behavior in the wild?

Stocking of hatchery-reared fishes has been used with variable success as a management action to promote the recovery of populations and species. The practice has been controversial for several reasons, including uncertainty about whether the hatchery rearing experience may affect reproduction after release. Fine-scale acoustic telemetry was used during three spawning seasons to test whether hatchery rearing affects the reproductive behavior of lake trout using a spawning shoal complex in northern Lake Huron. Within sex, wild- and hatchery-reared fish behaved similarly, but significant behavioral differences occurred between sexes. Lake trout of both sexes moved synchronously onto the spawning shoals at the completion of autumn thermal turnover and occupied the same spawning sites (confirmed visually by presence of fertilized eggs) on the shoals. Male lake trout tended to congregate directly on spawning sites, with duration of occupancy varying greatly among years. Female lake trout spent less time on spawning shoals than males and congregated less at spawning sites on shoals. Most fish visited multiple spawning sites among shoals per season, with many making multiple transits among individual spawning sites. We found no evidence to support the hypothesis that hatchery rearing impairs spawning behavior of lake trout and, therefore, conclude that behavior deficiencies on the spawning ground are likely not an impediment to rehabilitation of lake trout in northern Lake Huron. Our study narrows the field of possible impediments to lake trout rehabilitation in the Great Lakes and provides insights that expand the conceptual model of lake trout spawning behavior.