Multiscale relationships between stream temperature and juvenile recruitment in an imperilled freshwater fish

2020 ◽  
Vol 71 (10) ◽  
pp. 1269
Author(s):  
Mischa P. Turschwell ◽  
Ben Stewart-Koster ◽  
Stephen R. Balcombe ◽  
Fran Sheldon ◽  
Erin E. Peterson

The distribution and population structure of organisms is governed by a broad suite of biotic and abiotic variables, interacting across multiple scales. Recruitment is a key demographic process critical to the maintenance of successful populations. Isolating and quantifying the multiscale environmental drivers of recruitment is vital for species conservation, especially for those species with traits that increase their susceptibility to local extirpation. We developed a Bayesian hierarchical model to quantify the relationship between the rate of recruitment in a locally threatened river blackfish (Gadopsis marmoratus) and environmental predictors across two spatial scales. There was a 0.99 probability that increased broad-scale stream temperature negatively affected juvenile recruitment rate. We also found that there was a 0.97 probability that the fine-scale relationship between recruitment rate and riparian foliage cover was dependent on temperature. This suggests that broad-scale thermal conditions provide the template upon which at least one local environmental variable influences recruitment rate. Understanding drivers influencing key population processes and the spatial scales at which they operate is critical to gaining an insight into likely changes in population persistence for potentially imperilled species, along with the potential future effects of habitat degradation and climate warming on freshwater fishes in general.

2020 ◽  
Vol 12 (3) ◽  
pp. 395 ◽  
Author(s):  
Sergio A. Cabrera-Cruz ◽  
Emily B. Cohen ◽  
Jaclyn A. Smolinsky ◽  
Jeffrey J. Buler

The distributions of birds during migratory stopovers are influenced by a hierarchy of factors. For example, in temperate regions, migrants are concentrated near areas of bright artificial light at night (ALAN) and also the coastlines of large water bodies at broad spatial scales. However, less is known about what drives broad-scale stopover distributions in the tropics. We quantified seasonal densities of nocturnally migrating landbirds during spring and fall of 2011–2015, using two weather radars on the Yucatan peninsula, Mexico (Sabancuy and Cancun). We tested the influence of environmental predictors in explaining broad-scale bird stopover densities. We predicted higher densities in areas (1) closer to the coast in the fall and farther away in spring and (2) closer to bright ALAN and with lower ALAN intensity in both seasons. We found that birds were more concentrated near the coastline in the fall and away from it in spring around Cancun but not Sabancuy. Counter to our expectations, we detected increased bird densities with increased distance from lights in spring around Sabancuy, and in both seasons around Cancun, suggesting avoidance of bright areas during those seasons. This is the first evidence of broad-scale bird avoidance of bright areas during stopover.


The Auk ◽  
2020 ◽  
Vol 137 (2) ◽  
Author(s):  
Karen L Wiebe

Abstract Natal dispersal and local recruitment are affected by factors both intrinsic and extrinsic to juveniles and may affect fitness. Understanding the relationship between dispersal and population density in birds has been hindered by a lack of long-term studies and a focus on resident species has neglected the role of weather operating at large spatial scales. I studied local recruitment and the reproductive consequences of natal dispersal distance within a population of Northern Flickers (Colaptes auratus), a migratory woodpecker. During a field study spanning 16 yr in British Columbia, 8,272 fledglings were banded and 138 males and 105 females recruited locally. The average annual local recruitment rate for males (3.36%) was greater than that for females (2.55%) and the propensity to recruit locally was positively correlated with an early hatch date and high body condition. Annual local recruitment was not associated with population density in the year of hatch but was positively correlated with population density in the year of settlement. Local recruitment was also positively correlated with warmer springs during migration, consistent with the phenology hypothesis that the location of settlement is affected by weather along the route. Among local recruits, natal dispersal distance was independent of the presence of parents and so dispersal was not a behavior to prevent inbreeding. However, settling closer to the natal site led to reproductive benefits in terms of earlier laying dates and better nest success. Therefore, juveniles may gain useful information about the location of nesting substrates, predation risk, and patchy food resources by exploring the landscape around their natal site during the post-fledging period and then settling in the familiar area after returning from migration.


2019 ◽  
Vol 286 (1916) ◽  
pp. 20191989 ◽  
Author(s):  
M. C. Yates ◽  
E. Bowles ◽  
D. J. Fraser

Little empirical work in nature has quantified how wild populations with varying effective population sizes and genetic diversity perform when exposed to a gradient of ecologically important environmental conditions. To achieve this, juvenile brook trout from 12 isolated populations or closed metapopulations that differ substantially in population size and genetic diversity were transplanted to previously fishless ponds spanning a wide gradient of ecologically important variables. We evaluated the effect of genome-wide variation, effective population size ( N e ), pond habitat, and initial body size on two fitness correlates (survival and growth). Genetic variables had no effect on either fitness correlate, which was determined primarily by habitat (pond temperature, depth, and pH) and initial body size. These results suggest that some vertebrate populations with low genomic diversity, low N e , and long-term isolation can represent important sources of variation and are capable of maintaining fitness in, and ultimately persisting and adapting to, changing environments. Our results also reinforce the paramount importance of improving available habitat and slowing habitat degradation for species conservation.


1998 ◽  
Vol 55 (S1) ◽  
pp. 9-21 ◽  
Author(s):  
Carol L Folt ◽  
Keith H Nislow ◽  
Mary E Power

The Atlantic salmon (Salmo salar) is a model species for studying scale issues (i.e., the extent, duration, and resolution of a study or natural process) in ecology. Major shifts in behavior and habitat use over ontogeny, along with a relatively long life span and large dispersal and migration distances, make scale issues critical for effective conservation, management, and restoration of this species. The scale over which a process occurs must be linked to the research design and we illustrate this with a discussion of resource tracking by Atlantic salmon. Identifying scale inconsistencies (e.g., when a process is evident at one scale but not another) is shown to be an effective means by which some scale-dependent processes are understood. We review the literature to assess the temporal and spatial scales used in Atlantic salmon research and find most current studies appear to sacrifice spatial and temporal extent for increased resolution. Finally, we discuss research strategies for expanding the temporal and spatial scales in salmon research, such as conducting multiple scales studies to elucidate scale inconsistencies, identifying mechanisms, and using techniques and approaches to generalize across studies and over time and space.


2019 ◽  
Vol 7 ◽  
Author(s):  
Paulo Borges ◽  
Lucas Lamelas-Lopez ◽  
Isabel Amorim ◽  
Anja Danielczak ◽  
Mário Boieiro ◽  
...  

Azorean volcanic cave biodiversity is under considerable pressure due to ongoing threats of pollution, land use change, touristic activities or climate change. In this contribution, we present the IUCN Red List profiles of 15 cave-adapted arthropod species, endemic to the Azorean archipelago, including species belonging to the speciose genus Trechus (Carabidae), which is represented in Azores by seven species. The objective of this paper is to assess all endemic Azorean cave-adapted species and advise on possible future research and conservation actions critical for the long-term survival of the most endangered species. Most species have a restricted distribution (i.e. occur in one or two caves), very small extent of occurrence (EOO) and a small area of occupancy (AOO). A continuing decline in the number of mature individuals is inferred from the ongoing cave habitat degradation. The two troglobitic species of the homopteran genus Cixius are in great danger of extinction due to major land-use changes in epigean habitats above their known localities. We suggest, as future measures of conservation, the regular monitoring of the species (every five years), the creation of additional protected caves, the limitation of several aggressive activities around the caves (e.g. decreasing pasture intensification) and in some cases the creation of fences in the entrance of the most important caves.


Author(s):  
Bérengère Husson ◽  
Gregoire Certain ◽  
Anatoly Filin ◽  
Benjamin Planque

AbstractMany marine species are shifting their distribution poleward in response to climate change. The Barents Sea, as a doorstep to the fast-warming Arctic, is experiencing large scale changes in its environment and its communities. This paper aims at understanding what environmental predictors limit fish species habitats in the Barents Sea and discuss their possible evolution in response to the warming of the Arctic.Species distribution models usually aim at predicting the probability of presence or the average abundance of a species, conditional on environmental drivers. A complementary approach is to determine suitable habitats by modelling the upper limit of a species’ response to environmental factors. Using quantile regressions, we model the upper limit of biomass for 33 fish species in the Barents Sea in response to 10 environmental predictors. Boreal species are mainly limited by temperatures and most of them are expected to be able to expand their distribution in the Barents Sea when new thermally suitable habitats become available, in the limit of bathymetric constraints. Artic species are often limited by several predictors, mainly depth, bottom and surface temperature and ice cover, and future habitats are hard to predict qualitatively. Widespread species like the Atlantic cod are not strongly limited by the selected variables at the scale of the study, and current and future suitable habitats are harder to predict. These models can be used as input to integrative tools like end-to-end models on the habitat preference and tolerance at the species scale to inform resource management and conservation.


2021 ◽  
Author(s):  
◽  
Benjamin Magana-Rodriguez

<p>The current crisis in loss of biodiversity requires rapid action. Knowledge of species' distribution patterns across scales is of high importance in determining their current status. However, species display many different distribution patterns on multiple scales. A positive relationship between regional (broad-scale) distribution and local abundance (fine-scale) of species is almost a constant pattern in macroecology. Nevertheless interspecific relationships typically contain much scatter. For example, species that possess high local abundance and narrow ranges, or species that are widespread, but locally rare. One way to describe these spatial features of distribution patterns is by analysing the scaling properties of occupancy (e.g., aggregation) in combination with knowledge of the processes that are generating the specific spatial pattern (e.g., reproduction, dispersal, and colonisation). The main goal of my research was to investigate if distribution patterns correlate with plant life-history traits across multiple scales. First, I compared the performance of five empirical models for their ability to describe the scaling relationship of occupancy in two datasets from Molesworth Station, New Zealand. Secondly, I analysed the association between spatial patterns and life history traits at two spatial scales in an assemblage of 46 grassland species in Molesworth Station. The spatial arrangement was quantified using the parameter k from the Negative Binomial Distribution (NBD). Finally, I investigated the same association between spatial patterns and life-history traits across local, regional and national scales, focusing in one of the most diverse families of plant species in New Zealand, the Veronica sect. Hebe (Plantaginaceae). The spatial arrangement was investigated using the mass fractal dimension. Cross-species correlations and phylogenetically independent contrasts were used to investigate the relationships between plant life-history traits and spatial patterns on both data bases. There was no superior occupancy-area model overall for describing the scaling relationship, however the results showed that a variety of occupancy-area models can be fit to different data sets at diverse spatial scales using nonlinear regression. Additionally, here I showed that it is possible to deduce and extrapolate information on occupancy at fine scales from coarse-scale data. For the 46 plantassemblage in Molesworth Station, Specific leaf area (SLA) exhibits a positive association with aggregation in cross-species analysis, while leaf area showed a negative association, and dispersule mass a positive correlation with degree of aggregation in phylogenetic contrast analysis at a local-scale (20 × 20 m resolution). Plant height was the only life-history trait that was associated with degree of aggregation at a regional-scale (100 × 60 mresolution). For the Veronica sect. Hebe dataset, leaf area showed a positive correlation with aggregation while specific leaf area showed a negative correlation with aggregation at a fine local-scale (2.5-60 m resolution). Inflorescence length, breeding system and leaf area showed a negative correlation with degree of aggregation at a regional-scale (2.5-20 km resolution). Height was positively associated with aggregation at national-scale (20-100 km resolution). Although life-history traits showed low predictive ability in explaining aggregation throughout this thesis, there was a general pattern about which processes and traits were important at different scales. At local scales traits related to dispersal and completion such as SLA , leaf area, dispersule mass and the presence of structures in seeds for dispersal, were important; while at regional scales traits related to reproduction such as breeding system, inflorescence length and traits related to dispersal (seed mass) were significant. At national scales only plant height was important in predicting aggregation. Here, it was illustrated how the parameters of these scaling models capture an important aspect of spatial pattern that can be related to other macroecological relationships and the life-history traits of species. This study shows that when several scales of analysis are considered, we can improve our understanding about the factors that are related to species' distribution patterns.</p>


Diversity ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 101 ◽  
Author(s):  
Sándor Bartha ◽  
Roberto Canullo ◽  
Stefano Chelli ◽  
Giandiego Campetella

Patterns of diversity across spatial scales in forest successions are being overlooked, despite their importance for developing sustainable management practices. Here, we tested the recently proposed U-shaped biodiversity model of forest succession. A chronosequence of 11 stands spanning from 5 to 400 years since the last disturbance was used. Understory species presence was recorded along 200 m long transects of 20 × 20 cm quadrates. Alpha diversity (species richness, Shannon and Simpson diversity indices) and three types of beta diversity indices were assessed at multiple scales. Beta diversity was expressed by a) spatial compositional variability (number and diversity of species combinations), b) pairwise spatial turnover (between plots Sorensen, Jaccard, and Bray–Curtis dissimilarity), and c) spatial variability coefficients (CV% of alpha diversity measures). Our results supported the U-shaped model for both alpha and beta diversity. The strongest differences appeared between active and abandoned coppices. The maximum beta diversity emerged at characteristic scales of 2 m in young coppices and 10 m in later successional stages. We conclude that traditional coppice management maintains high structural diversity and heterogeneity in the understory. The similarly high beta diversities in active coppices and old-growth forests suggest the presence of microhabitats for specialist species of high conservation value.


Author(s):  
Maria A Diuk-Wasser ◽  
Meredith C VanAcker ◽  
Maria P Fernandez

Abstract The incidence of tick-borne diseases has increased in recent decades and accounts for the majority of vector-borne disease cases in temperate areas of Europe, North America, and Asia. This emergence has been attributed to multiple and interactive drivers including changes in climate, land use, abundance of key hosts, and people’s behaviors affecting the probability of human exposure to infected ticks. In this forum paper, we focus on how land use changes have shaped the eco-epidemiology of Ixodes scapularis-borne pathogens, in particular the Lyme disease spirochete Borrelia burgdorferi sensu stricto in the eastern United States. We use this as a model system, addressing other tick-borne disease systems as needed to illustrate patterns or processes. We first examine how land use interacts with abiotic conditions (microclimate) and biotic factors (e.g., host community composition) to influence the enzootic hazard, measured as the density of host-seeking I. scapularis nymphs infected with B. burgdorferi s.s. We then review the evidence of how specific landscape configuration, in particular forest fragmentation, influences the enzootic hazard and disease risk across spatial scales and urbanization levels. We emphasize the need for a dynamic understanding of landscapes based on tick and pathogen host movement and habitat use in relation to human resource provisioning. We propose a coupled natural-human systems framework for tick-borne diseases that accounts for the multiple interactions, nonlinearities and feedbacks in the system and conclude with a call for standardization of methodology and terminology to help integrate studies conducted at multiple scales.


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