Local Habitat Research Articles

Freshwater-related species richness in Natura 2000 sites strongly depends on the surrounding land use besides local habitat conditions

The Birds and Habitats Directive are the cornerstones of Europe's nature conservation policy and the resulting Natura 2000 (N2k) sites form the largest coordinated network of protected areas in the world. Despite the ambitious targets of these directives and decades of efforts, biodiversity, especially of freshwater-related species, continues to decline in Europe. While multiple stressors at larger spatial scales are known to limit the effect of river restoration projects, the importance of surrounding land use outside the N2k sites for freshwater-related species richness inside N2k sites has rarely been studied. Conditional inference forests were used to assess the importance of land use in the surrounding and upstream of the German N2k sites compared to local habitat conditions inside. Freshwater-related species richness depended on land use in the surrounding besides local habitat conditions. Results indicated that this was especially true for birds in small N2k sites embedded in a wet, diverse, and patchy landscape and for non-birds due to the provision of additional habitats outside the N2k sites. Given that most N2k sites in Europe are rather small, the surrounding habitat conditions and land use potentially influences and affects freshwater-related species in many N2k sites across Europe. The additional conservation and restoration areas to be designated under the EU Biodiversity Strategy and upcoming EU restoration law should either be large enough or surrounded by extensive land use to optimize their effect on freshwater-related species.

Spatial patterns of seedlings dominated by proximity to deadwood and adult trees for Pinus flexilis and Pinus longaeva

The spatial patterns of trees are a defining feature of forests, yet because of the long lifespan of trees, the full origins of these spatial patterns remain unclear. We used 15.6 ha of a mapped forest plot to assess the local habitat characteristics and spatial structure of 1,550 naturally established seedlings and 1,955 adults of Pinus flexilis (limber pine) and Pinus longaeva (Great Basin bristlecone pine) in southern Utah, USA. For both species, proximity to deadwood (large end diameter ≥ 10 cm) and mature trees were key parameters of habitat, likely indicating abiotic or biotic facilitation. Both seedlings and mature trees were highly aggregated 0.0–2.5 m around large pieces of deadwood, which can persist in this ecosystem for centuries or millennia. Seedlings were most often located around deadwood 15–22 cm in diameter, though deadwood size had little influence on the distance at which seedlings established. Seedlings of both P. flexilis and P. longaeva were abundant near heterospecific adult Pinus. The elevational distribution of seedlings and adults of both species were not different, indicating a regeneration niche similar to the niche of mature trees and also that changing climate at this site has not yet affected species distributions. Low amounts of manganese and higher levels of pH and potassium in the mineral soil were associated with P. longaeva seedlings but were less important for P. flexilis. Edaphic patterns combined with the presence of deadwood define the overlap between seedling and mature species habitat and identify the key drivers influencing the spatial structure in this high-elevation, old-growth forest. Likely, persistence of these two Pinus species as well as regeneration or site colonization is more favorable in the presence of large deadwood.

Plant blindness represents the loss of generational knowledge and cultural identity

AbstractPlant blindness, the inability of people to notice plants, is of current interest in the natural sciences community. It has been hypothesized that communities of varying cultures may have improved plant sight. Researchers used an online survey to assess citizens ability to identify plants. The survey also intended to address the concern of elders from the Turtle Mountain Band of Chippewa Indians (TMBCI) who have seen reduced abundance of traditional plant species. The survey assessed knowledge of local wetland, grassland, and forest habitats; names of plants; and how citizens use plant features in identification. The survey gathered demographic data to determine trends across different demographic groups including age and ethnicity. A total of 216 participants took the survey, the majority classified themselves as female and Native American or Alaska Native. Our findings indicated that participants were able to identify forest and wetland plants the best, but struggled with grassland plants. Older individuals were more able to identify plants when compared to younger individuals. Ecologically, increasing plant knowledge is vital to rebuilding and maintaining the diversity of local habitats, but culturally the impacts are just as important. The practice of using traditional plants in medicine and ceremony is an integral part of the TMBCI culture. As both the knowledge and the plants disappear in younger generations, so does their unique cultural identity.

Seasonal variation in trophic niches and niche overlap between native and introduced cyprinid fishes

It is critical to understand the potential effects of non-native species, especially on ecologically similar native species, and to reveal their trophic relationships. Cyprinid invasive fishes, Carassius gibelio, and translocated fish Cyprinus carpio has been introduced to the Karacaören I reservoir located in the upstream reach of the Aksu River basin. Karacaören reservoir is also an important local habitat for native Cyprinid fishes, Capoeta antalyensis and Squalius fellowesii. In this study, we evaluated the trophic structure and interspecies trophic interactions (as isotopic niches and niche overlaps) of these Cyprinid fish using stable C and N isotopes analysis as measured by Isotope Ratio Mass Spectrometer. While equally all food sources contributed to the biomass of all fish species in the summer, their biomass is supported by more specialized sources in the winter season. Our results revealed increased niche breadth with increased niche overlap between C. antalyensis and C. gibelio, and C. carpio, and among C. gibelio and C. carpio in the summer, while decreased niche breadth with decreased niche overlap in the winter season. Interspecific competition has led to trophic niche divergence, which may facilitate the coexistence of native species with introduced fishes. Non-native fish were determined to have larger niche widths, which may contribute to their invasion success.

PAReTT: A Python Package for the Automated Retrieval and Management of Divergence Time Data from the TimeTree Resource for Downstream Analyses

Evolutionary processes happen gradually over time and are, thus, considered time dependent. In addition, several evolutionary processes are either adaptations to local habitats or changing habitats, otherwise restricted thereby. Since evolutionary processes driving speciation take place within the landscape of environmental and temporal bounds, several published studies have aimed at providing accurate, fossil-calibrated, estimates of the divergence times of both extant and extinct species. Correct calibration is critical towards attributing evolutionary adaptations and speciation both to the time and paleogeography that contributed to it. Data from more than 4000 studies and nearly 1,50,000 species are available from a central TimeTree resource and provide opportunities of retrieving divergence times, evolutionary timelines, and time trees in various formats for most vertebrates. These data greatly enhance the ability of researchers to investigate evolution. However, there is limited functionality when studying lists of species that require batch retrieval. To overcome this, a PYTHON package termed Python-Automated Retrieval of TimeTree data (PAReTT) was created to facilitate a biologist-friendly interaction with the TimeTree resource. Here, we illustrate the use of the package through three examples that includes the use of timeline data, time tree data, and divergence time data. Furthermore, PAReTT was previously used in a meta-analysis of candidate genes to illustrate the relationship between divergence times and candidate genes of migration. The PAReTT package is available for download from GitHub or as a pre-compiled Windows executable, with extensive documentation on the package available on GitHub wiki pages regarding dependencies, installation, and implementation of the various functions.

A New Coastal Crawler Prototype to Expand the Ecological Monitoring Radius of OBSEA Cabled Observatory

The use of marine cabled video observatories with multiparametric environmental data collection capability is becoming relevant for ecological monitoring strategies. Their ecosystem surveying can be enforced in real time, remotely, and continuously, over consecutive days, seasons, and even years. Unfortunately, as most observatories perform such monitoring with fixed cameras, the ecological value of their data is limited to a narrow field of view, possibly not representative of the local habitat heterogeneity. Docked mobile robotic platforms could be used to extend data collection to larger, and hence more ecologically representative areas. Among the various state-of-the-art underwater robotic platforms available, benthic crawlers are excellent candidates to perform ecological monitoring tasks in combination with cabled observatories. Although they are normally used in the deep sea, their high positioning stability, low acoustic signature, and low energetic consumption, especially during stationary phases, make them suitable for coastal operations. In this paper, we present the integration of a benthic crawler into a coastal cabled observatory (OBSEA) to extend its monitoring radius and collect more ecologically representative data. The extension of the monitoring radius was obtained by remotely operating the crawler to enforce back-and-forth drives along specific transects while recording videos with the onboard cameras. The ecological relevance of the monitoring-radius extension was demonstrated by performing a visual census of the species observed with the crawler’s cameras in comparison to the observatory’s fixed cameras, revealing non-negligible differences. Additionally, the videos recorded from the crawler’s cameras during the transects were used to demonstrate an automated photo-mosaic of the seabed for the first time on this class of vehicles. In the present work, the crawler travelled in an area of 40 m away from the OBSEA, producing an extension of the monitoring field of view (FOV), and covering an area approximately 230 times larger than OBSEA’s camera. The analysis of the videos obtained from the crawler’s and the observatory’s cameras revealed differences in the species observed. Future implementation scenarios are also discussed in relation to mission autonomy to perform imaging across spatial heterogeneity gradients around the OBSEA.

Detection, occupancy, and abundance of the alligator snapping turtle in Texas

AbstractThe alligator snapping turtle (Macrochelys temminckii) is a long‐lived species that is widely distributed across the southeastern United States. Both these characteristics make monitoring its occupancy and abundance particularly challenging. In 2020 and 2021, we conducted hoop trap surveys at 51 permanent water bodies across the Texas, USA, range of the species to estimate occupancy and average abundance with site occupancy models and multinomial N‐mixture models, respectively. We confirmed the species to be present at 61% of surveyed locations. Mean detection probability was 0.77, and was influenced methodologically by the spacing of traps, and environmentally by lunar phase and water flow velocity. Mean occupancy probability was 0.82, and mean estimated abundance was 7.57 turtles/site. Our data provided evidence that the species has a higher occurrence probability in waters of highly forested catchments, and is most probable to occur in highest abundances at median latitudes within its Texas range. Despite known microhabitat preferences of the species, instream habitat characteristics (e.g., canopy coverage, depth, sinuosity) did not strongly influence its occupancy or abundance. Spatial dynamics of the occupancy and abundance of the species in Texas are influenced by landscape features more than local habitat. These results further corroborate the importance of watershed land cover to aquatic organisms, and our methods provide a standardized template for monitoring and quantifying important demographic parameters of the species across multiple locations while accounting for imperfect detection.

Perception and kairomonal response of the coccinellid predator (Harmonia axyridis) to the fall armyworm (Spodoptera frugiperda) sex pheromone.

Pheromone cues released from hosts or prey are of crucial importance to natural enemies for prey and habitat location. The use of herbivorous insect sex pheromones has long been considered as a potential pest control alternative that is non-toxic and harmless to beneficials. We hypothesized that Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), a major predatory coccinellid beetle of the devastating migratory pest Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), could perceive and use the sex pheromone of S. frugiperda to locate its habitat. Here we tested the electrophysiological and behavioral responses of H. axyridis to the two components Z7-12:Ac and Z9-14:Ac of S. frugiperda sex pheromone by using electroantennography (EAG) and Y-tube bioassay. The 3D modeling of H. axyridis odorant-binding proteins (HaxyOBPs) and molecular docking were also performed. The results showed that both female and male H. axyridis exhibited significantly higher electrophysiological and behavioral responses to Z9-14:Ac at the concentrations of 0.001, 0.01, and 0.1μg/μL, while no significant electrophysiological and behavioral responses of H. axyridis were observed to Z7-12:Ac. The blend of Z7-12:Ac and Z9-14:Ac at the ratio of 1:100 had a significant attraction to both male and female H. axyridis at the concentrations of 0.01 and 0.1μg/μL based on electrophysiological and behavioral assays, but no significant behavioral responses were observed at the ratios of 1:9. According to the 3D modeling of HaxyOBPs and molecular docking, HaxyOBP12 has a good affinity with Z9-14:Ac. Z9-14:Ac is bound to the HaxyOBP12 by hydrogen bonding and hydrophobic interactions. However, there were no credible docking results between HaxyOBPs and Z7-12:Ac. Our findings revealed that H. axyridis can perceive Z9-14:Ac and could use it as a chemical cue to locate prey habitat. We speculated that Z7-12:Ac, which showed some antagonistic effect toward the response of H. axyridis to Z9-14:Ac, could improve the adaptability of S. frugiperda in the presence of predators. This study provides new insights into the application of pheromones to manipulate natural enemy behavior for pest control.

Assessment Of Anthropogenic Impact On Forest Ecosystem: A Case Study Of Kumbhalgarh Wildlife Sanctuary, India

In the era of the modern world, natural resources are continuously diminishing and simultaneously the human population is also increasing, which is alarming for the present and future world. Global biodiversity is playing a pivotal role in all ecosystem services, meanwhile, anthropogenic activities and encroachment are the main drivers for the widespread loss of local biodiversity. In India, Kumbhalgarh Wildlife Sanctuary is situated in the world’s oldest Aravali Mountain range. Near protected areas of this wildlife sanctuary have an entire concentration of rural populations, which are interdependence with this forest ecosystem. The key objective of the research study is to measure the anthropogenic impact on Kumbhalgarh Wildlife Sanctuary. It’s a micro-level study based on primary and secondary data through GIS mapping as well as Socio- Economic & Physical factors to inter-connect with forest habitats. Especially, core and periphery LULC have been obtained from the Multispectral images from ETM+ and OLI sensors of Landsat satellites. This study examines the spatial and temporal patterns of LULC change along the boundary of Kumbhalgarh from 2000 to 2020. The research also describes land use and land cover pattern, forest cover and vegetation index, and human encroachment, Eventually, the situation would be alarming for the local biodiversity and habitat due to the high pressure of anthropogenic activities and encroachment.

Visual acuity of Empoasca onukii (Hemiptera, Cicadellidae)

Empoasca onukii is a common tea plant pest with a preference for the color yellow. Past work has shown that host leaf color is a key cue for habitat location for E. onukii. Before studying the effect of foliage shape, size, or texture on habitat localization, it is necessary to determine the visual acuity and effective viewing distance of E. onukii. In this study, a combination of 3D microscopy and X-ray microtomography showed that visual acuity did not significantly differ between females and males, but there were significant differences in the visual acuity and optical sensitivity among five regions of E. onukii's compound eyes. The dorsal ommatidia had the highest visual acuity at 0.28 cycles per degree (cpd) but the lowest optical sensitivity (0.02 μm2sr), which indicated a trade-off between visual resolution and optical sensitivity for E. onukii. The visual acuity determined from the behavioral experiment was 0.14 cpd; E. onukii exhibited low-resolution vision and could only distinguish the units in a yellow/red pattern within 30 cm. Therefore, visual acuity contributes to the limited ability of E. onukii to distinguish the visual details of a distant target, which might be perceived as a lump of blurred color of intermediate brightness.

Future Increase in Aridity Drives Abrupt Biodiversity Loss Among Terrestrial Vertebrate Species

AbstractThe planet is predicted to become drier because of accelerating global warming, increasing great challenges to the survival of terrestrial species. However, the understanding of when and where increasing aridity in the future will lead to abrupt biodiversity loss is still limited. Here, we predicted the spatiotemporal dynamics of future vertebrate biodiversity loss driven by increasing aridity at the assemblage scale under the scenario framework of the shared socio‐economic pathways (SSPs) and representative concentration pathways (RCPs). The results show that, under the high‐emissions scenario of SSP5‐8.5, more than 24.19% of terrestrial assemblages are projected to have at least one vertebrate species exposed to unprecedented aridity conditions by 2100, leading to 55.29% of terrestrial vertebrate species experiencing local habitat loss. In addition, the mean magnitude of global exposure is expected to reach 17.47% by 2100. Within these assemblages, most species will be simultaneously exposed to unprecedented aridity conditions, with an average exposure abruptness of 78.00%, most of which will occur intensively after 2050. If we manage to reduce greenhouse gas emissions to the SSP1‐2.6 (SSP2‐4.5) scenario, the magnitude of exposure can significantly decrease to 7.35% (10.56%), and the onset of exposure can be delayed by 43 (30) years, averaging approximately 30% (14%) of vertebrate species from local habitat loss. Our findings also highlight that the concurrent extremes of increasing aridity and rising temperature in Southeast Asia and Amazon rainforests may amplify exposure risks, which can motivate decision‐makers to respond early and effectively to mitigate abrupt ecological disruption.

Measuring habitat quality for waterbirds: A review.

Quantifying habitat quality is dependent on measuring a site's relative contribution to population growth rate. This is challenging for studies of waterbirds, whose high mobility can decouple demographic rates from local habitat conditions and make sustained monitoring of individuals near-impossible. To overcome these challenges, biologists have used many direct and indirect proxies of waterbird habitat quality. However, consensus on what methods are most appropriate for a given scenario is lacking. We undertook a structured literature review of the methods used to quantify waterbird habitat quality, and provide a synthesis of the context-dependent strengths and limitations of those methods. Our search of the Web of Science and Scopus databases returned a sample of 666 studies, upon which our review was based. The reviewed studies assessed habitat quality by either measuring habitat attributes (e.g., food abundance, water quality, vegetation structure), or measuring attributes of the waterbirds themselves (e.g., demographic parameters, body condition, behavior, distribution). Measuring habitat attributes, although they are only indirectly related to demographic rates, has the advantage of being unaffected by waterbird behavioral stochasticity. Conversely, waterbird-derived measures (e.g., body condition, peck rates) may be more directly related to demographic rates than habitat variables, but may be subject to greater stochastic variation (e.g., behavioral change due to presence of conspecifics). Therefore, caution is needed to ensure that the measured variable does influence waterbird demographic rates. This assumption was usually based on ecological theory rather than empirical evidence. Our review highlighted that there is no single best, universally applicable method to quantify waterbird habitat quality. Individual project specifics (e.g., time frame, spatial scale, funding) will influence the choice of variables measured. Where possible, practitioners should measure variables most directly related to demographic rates. Generally, measuring multiple variables yields a better chance of accurately capturing the relationship between habitat characteristics and demographic rates.

Riverine distribution and abundance of Japanese eel in Shikoku, south‐western Japan: Varying importance of regional and local factors

Abstract Regional and local habitat factors affecting the distribution and abundance of Japanese eel (Anguilla japonica) were systematically analysed in 123 reaches of 21 stream systems in south‐western Japan, with particular attention paid to human habitat modification, such as artificial barriers and concrete revetment. The density of Japanese eel decreased upstream, and they were absent from the upper reaches of each stream system. The upper limits of their distribution were explained by the distance from the sea and the channel gradient, rather than barriers. However, the number of barriers had the highest explanatory capacity for the upstream decline in abundance of small eels (<40 cm in total length). Analyses of the relative importance of regional and local habitat factors showed that the number of barriers (regional factor) was more important than local habitat factors in determining small eel abundance, whereas regional and local habitat factors (e.g. concrete revetment or cover habitat) were similarly important for large eel abundance. These results suggest that: (i) barriers are not a major factor limiting the distribution (presence/absence) of the Japanese eel in the streams studied; (ii) barriers can substantially decrease the abundance of young eels; and (iii) as eels grow older and larger, local habitat factors, such as bank conditions and cover, become more important in determining their abundance. The results for the relative importance of regional and local habitat factors suggest that in habitat restoration for the Japanese eel, priority should be given to mitigating barrier effects. The improvement of longitudinal connectivity to facilitate colonization by young eels is primarily needed for a more efficient use of the existing carrying capacity of streams. The improvement of local habitat conditions to increase the carrying capacity should be conducted in stream reaches free from barrier effects.

Adaptive protein evolution through length variation of short tandem repeats in Arabidopsis.

Intrinsically disordered protein regions are of high importance for biotic and abiotic stress responses in plants. Tracts of identical amino acids accumulate in these regions and can vary in length over generations because of expansions and retractions of short tandem repeats at the genomic level. However, little attention has been paid to what extent length variation is shaped by natural selection. By environmental association analysis on 2514 length variable tracts in 770 whole-genome sequenced Arabidopsis thaliana, we show that length variation in glutamine and asparagine amino acid homopolymers, as well as in interaction hotspots, correlate with local bioclimatic habitat. We determined experimentally that the promoter activity of a light-stress gene depended on polyglutamine length variants in a disordered transcription factor. Our results show that length variations affect protein function and are likely adaptive. Length variants modulating protein function at a global genomic scale has implications for understanding protein evolution and eco-evolutionary biology.

Permeability of coastal biogeographic barriers to marine larval dispersal on the east and west coasts of North America

AbstractAimWe assess the role of contemporary oceanography and species traits in shaping observed patterns of biogeography over broad spatial scales.LocationOur study domain covers the east and west coasts of North America, from 30° to 73° N on the east coast and 33° to 73° N on the west coast.Time periodHydrodynamic models use climatological fields from 1990 to 2015 on the east coast, and 1993 to 2018 on the west coast.Major taxa studiedModel simulations represent larval dispersal for generalized benthic invertebrate species distributed in the subtidal zone from 10 to 100 m depth, with planktonic larval durations ranging from 21–60 days.MethodsWe conducted a literature review to identify major biogeographic barriers along the east and west coasts of North America, and then assessed the permeability of these barriers to larval dispersal using Lagrangian particle tracking. We ran a series of simulations in which we varied the suitable habitat distribution, planktonic larval duration, and spawning seasonality of simulated larvae (i.e., particles) to assess the effects of species traits on biogeography.ResultsOur results showed a strong alignment of observed biogeographic barriers with larval dispersal patterns, with high variation in barrier permeability depending on the traits of the species considered. The location of suitable habitat and the season during which particle release occurred were the biological traits that drove much of the variation in barrier permeability among simulations on both coasts.Main conclusionsOur results indicate an important role of contemporary oceanographic and geographic features in determining the biogeography of species whose primary dispersal is during larval stages, suggesting that climate change is likely to alter patterns of species biogeography. Our results also demonstrate that species traits play a strong role in determining the location and strength of biogeographic barriers.

Changes in trophic ecology of mobile predators in response to rainforest degradation

Abstract Accelerating loss and degradation of tropical forests has led to a pressing need to understand the conservation value of remaining forests. Whereas most studies focus on the responses in community composition and taxonomic richness, more sensitive responses to habitat degradation are likely to be apparent through changes in the trophic complexity of generalist predators. Food web theory predicts that both trophic position and niche breadth of predators decrease with habitat degradation, with consequences for biotic interactions and ecosystem functioning. Using a stable isotope approach, we analysed trophic positions and niche breaths of an important guild of top predators: insectivorous bats, in the tropical forests of Sabah, Borneo. We aimed to determine the responses in their trophic ecology across an experimental gradient of forest degradation at different spatial scales. At the landscape scale, trophic niche breadth contracted substantially (78%) in association with a narrow reduction (26%) in forest cover. However, food chains were longer in ecosystems with lower tree canopies, representative of localised habitat simplification. Marked differences in trophic niche breath of and trophic position between echolocation guilds provided further evidence for inter‐guild niche partitioning within bat assemblages. Overall, the functionally important shifts in trophic pathways discriminated among habitats of varying degrees of degradation more reliably than conventional community descriptors, such as diversity metrics. Synthesis and applications. This study reveals that habitat quality thresholds—below which we see substantial changes to trophic complexity—are higher than previously considered. Our analysis suggests that patches of forest with cover above 90% should be prioritised for conservation over more highly degraded ecosystems. As these effects were detected after approximately 30 years post‐logging, they likely reflect relatively long‐term responses to forest degradation.

Terrain Ruggedness and Canopy Height Predict Short-Range Dispersal in the Critically Endangered Black-and-White Ruffed Lemur.

Dispersal is a fundamental aspect of primates' lives and influences both population and community structuring, as well as species evolution. Primates disperse within an environmental context, where both local and intervening environmental factors affect all phases of dispersal. To date, research has primarily focused on how the intervening landscape influences primate dispersal, with few assessing the effects of local habitat characteristics. Here, we use a landscape genetics approach to examine between- and within-site environmental drivers of short-range black-and-white ruffed lemur (Varecia variegata) dispersal in the Ranomafana region of southeastern Madagascar. We identified the most influential drivers of short-range ruffed lemur dispersal as being between-site terrain ruggedness and canopy height, more so than any within-site habitat characteristic evaluated. Our results suggest that ruffed lemurs disperse through the least rugged terrain that enables them to remain within their preferred tall-canopied forest habitat. Furthermore, we noted a scale-dependent environmental effect when comparing our results to earlier landscape characteristics identified as driving long-range ruffed lemur dispersal. We found that forest structure drives short-range dispersal events, whereas forest presence facilitates long-range dispersal and multigenerational gene flow. Together, our findings highlight the importance of retaining high-quality forests and forest continuity to facilitate dispersal and maintain functional connectivity in ruffed lemurs.

Predicting biomass of resident kōkopu (Galaxias) populations using local habitat characteristics.

With the global decline of freshwater fishes, quantifying the body size-specific habitat use of vulnerable species is crucial for accurately evaluating population health, identifying the effects of anthropogenic stressors, and directing effective habitat restoration. Populations of New Zealand's endemic kōkopu species (Galaxias fasciatus, G. argenteus, and G. postvectis) have declined substantially over the last century in response to anthropogenic stressors, including habitat loss, migratory barriers, and invasive species. Despite well-understood habitat associations, key within-habitat features underpinning the reach-scale biomass of small and large kōkopu remain unclear. Here, we investigated whether the total biomass of large (> 90 mm) size classes of each kōkopu species and the composite biomass of all small (≤ 90 mm) kōkopu were associated with components of the physical environment that provided refuge and prey resources across fifty-seven 50-m stream reaches. Because kōkopu are nocturnal, populations were sampled by removal at night using headlamps and hand-nets until reaches were visually depleted. Based on Akaike's information criterion, greater large banded kōkopu biomass was most parsimoniously explained by greater pool volume and forest cover, greater large giant kōkopu biomass by greater bank cover and pool volume, and greater large shortjaw kōkopu biomass by greater substrate size and pool volume. In contrast, greater composite small kōkopu biomass was best explained by smaller substrate size, reduced bank cover, and greater pool volume. Local habitat associations therefore varied among kōkopu species and size classes. Our study demonstrates the importance of considering the ontogenetic shift in species' habitat use and provides an effective modelling approach for quantifying size-specific local habitat use of stream-dwelling fish.

Phytolith evidence for changes in the vegetation diversity and cover of a grassland ecosystem in Northeast China since the mid-Holocene

Accurate estimates of changes in the composition and diversity of grassland ecosystems, and an understanding of the mechanisms responsible, are essential for predicting future changes and for conservation planning. Here, we synthesize stratigraphic records of phytoliths, together with previously published pollen, diatom, carbonate and grain-size records, from a peat profile (LDBS) in the Songnen region of Northeast China. The results demonstrate that since the mid-Holocene this region was occupied by grassland, with C3 grasses always dominant but with C4 grasses progressively increasing. The species richness and plant cover were high and relatively stable for most of the studied interval, but they decreased significantly in the last ∼1,000 years. The long-term evolution of this grassland ecosystem was dominated by climate changes, but it was also affected by human activities and local habitat factors. The plant cover and several dominant plant taxa were climatically sensitive, while the C4 grasses also responded to changes in the water table and human activities. Species richness was relatively stable but it responded to long-term climatic changes. Phytolith-based reconstruction of Holocene plant community composition and diversity and their driving mechanisms can potentially be used to facilitate conservation planning in this temperate grassland ecosystem.

Climate-informed forecasts reveal dramatic local habitat shifts and population uncertainty for northern boreal caribou.

Most research on boreal populations of woodland caribou (Rangifer tarandus caribou) has been conducted in areas of high anthropogenic disturbance. However, a large portion of the species' range overlaps relatively pristine areas primarily affected by natural disturbances, such as wildfire. Climate-driven habitat change is a key concern for the conservation of boreal-dependent species, where management decisions have yet to consider knowledge from multiple ecological domains integrated into a cohesive and spatially explicit forecast of species-specific habitat and demography. We used a novel ecological forecasting framework to provide climate-sensitive projections of habitat and demography for five boreal caribou monitoring areas within the Northwest Territories (NWT), Canada, over 90 years. Importantly, we quantify uncertainty around forecasted mean values. Our results suggest habitat suitability may increase in central and southwest regions of the NWT's Taiga Plains ecozone but decrease in southern and northwestern regions driven by conversion of coniferous to deciduous forests. We do not project that boreal caribou population growth rates will change despite forecasted changes to habitat suitability. Our results emphasize the importance of efforts to protect and restore northern boreal caribou habitat despite climate uncertainty while highlighting expected spatial variations that are important considerations for local people who rely on them. An ability to reproduce previous work, and critical thought when incorporating sources of uncertainty, will be important to refine forecasts, derive management decisions, and improve conservation efficacy for northern species at risk.