scholarly journals Defining dual-axis landscape gradients of human influence for studying ecological processes

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0252364
Author(s):  
Benjamin Juan Padilla ◽  
Chris Sutherland
Keyword(s):  
Reciprocal Relationship ◽  
Ecological Communities ◽  
Human Influence ◽  
Natural Areas ◽  
Ecological Processes ◽  
American Robin ◽  
Landscape Modification ◽  
Ecological Responses ◽  
Landscape Characteristics ◽  
Us Cities

Ecological processes are strongly shaped by human landscape modification, and understanding the reciprocal relationship between ecosystems and modified landscapes is critical for informed conservation. Single axis measures of spatial heterogeneity proliferate in the contemporary gradient ecology literature, though they are unlikely to capture the complexity of ecological responses. Here, we develop a standardized approach for defining multi-dimensional gradients of human influence in heterogeneous landscapes and demonstrate this approach to analyze landscape characteristics of ten ecologically distinct US cities. Using occupancy data of a common human-adaptive songbird collected in each of the cities, we then use our dual-axis gradients to evaluate the utility of our approach. Spatial analysis of landscapes surrounding ten US cities revealed two important axes of variation that are intuitively consistent with the characteristics of multi-use landscapes, but are often confounded in single axis gradients. These were, a hard-to-soft gradient, representing transition from developed areas to non-structural soft areas; and brown-to-green, differentiating between two dominant types of soft landscapes: agriculture (brown) and natural areas (green). Analysis of American robin occurrence data demonstrated that occupancy responds to both hard-to-soft (decreasing with development intensity) and brown-to-green gradient (increasing with more natural area). Overall, our results reveal striking consistency in the dominant sources of variation across ten geographically distinct cities and suggests that our approach advances how we relate variation in ecological responses to human influence. Our case study demonstrates this: robins show a remarkably consistent response to a gradient differentiating agricultural and natural areas, but city-specific responses to the more traditional gradient of development intensity, which would be overlooked with a single gradient approach. Managing ecological communities in human dominated landscapes is extremely challenging due to a lack of standardized approaches and a general understanding of how socio-ecological systems function, and our approach offers promising solutions.

scholarly journals Defining dual-axis landscape gradients of human influence for studying ecological processes

2021 ◽  
Author(s):  
Benjamin Juan Padilla ◽  
Chris Sutherland
Keyword(s):  
Reciprocal Relationship ◽  
Ecological Communities ◽  
Human Influence ◽  
Natural Areas ◽  
Ecological Processes ◽  
Landscape Modification ◽  
Ecological Responses ◽  
Landscape Characteristics ◽  
Sources Of Variation ◽  
Us Cities

Ecological processes are strongly shaped by human landscape modification, and understanding the reciprocal relationship between ecosystems and modified landscapes is critical for informed conservation. Single axis measures of spatial heterogeneity proliferate in the contemporary gradient ecology literature, though they are unlikely to capture the complexity of ecological responses. Here, we develop a standardized approach for defining multi-dimensional gradients of human influence in heterogeneous landscapes and demonstrate this approach to analyze landscape characteristics of ten ecologically distinct US cities. Using occupancy data of a common human-adaptive songbird collected in each of the cities, we then use our dual-axis gradients to evaluate the utility of our approach. Spatial analysis of landscapes surrounding ten US cities revealed two important axes of variation that are intuitively consistent with the characteristics of multi-use landscapes, but are often confounded in single axis gradients. These were, a hard-to-soft gradient, representing transition from developed areas to non-structural soft areas; and brown-to-green, differentiating between two dominant types of soft landscapes: agriculture (brown) and natural areas (green). Analysis of songbird data demonstrated that occupancy responds to both hard-to-soft (decreasing with development intensity) and brown-to-green gradient (increasing with more natural area). Overall, our results reveal striking consistency in the dominant sources of variation across ten geographically distinct cities and suggests that our approach advances how we relate variation in ecological responses to human influence. Our case study demonstrates this: robins show a remarkably consistent response to a gradient differentiating agricultural and natural areas, but city-specific responses to the more traditional gradient of development intensity, which would be overlooked with a single gradient approach. Managing ecological communities in human dominated landscapes is extremely challenging due to a lack of standardized approaches and a general understanding of how socio-ecological systems function, and our approach offers promising solutions.

scholarly journals Phylogenetic overdispersion of plant species in southern Brazilian savannas

2009 ◽  
Vol 69 (3) ◽  
pp. 843-849 ◽  
Author(s):  
IA. Silva ◽  
MA. Batalha
Keyword(s):  
Phylogenetic Relationships ◽  
Plant Traits ◽  
Environmental Filtering ◽  
Southeastern Brazil ◽  
Ecological Communities ◽  
Ecological Interactions ◽  
Ecological Processes ◽  
Phylogenetic Structure ◽  
History Of ◽  
Phylogenetic Overdispersion

Ecological communities are the result of not only present ecological processes, such as competition among species and environmental filtering, but also past and continuing evolutionary processes. Based on these assumptions, we may infer mechanisms of contemporary coexistence from the phylogenetic relationships of the species in a community. We studied the phylogenetic structure of plant communities in four cerrado sites, in southeastern Brazil. We calculated two raw phylogenetic distances among the species sampled. We estimated the phylogenetic structure by comparing the observed phylogenetic distances to the distribution of phylogenetic distances in null communities. We obtained null communities by randomizing the phylogenetic relationships of the regional pool of species. We found a phylogenetic overdispersion of the cerrado species. Phylogenetic overdispersion has several explanations, depending on the phylogenetic history of traits and contemporary ecological interactions. However, based on coexistence models between grasses and trees, density-dependent ecological forces, and the evolutionary history of the cerrado flora, we argue that the phylogenetic overdispersion of cerrado species is predominantly due to competitive interactions, herbivores and pathogen attacks, and ecological speciation. Future studies will need to include information on the phylogenetic history of plant traits.

Marine Parasites and Disease in the Era of Global Climate Change

2021 ◽  
Vol 13 (1) ◽  
pp. 397-420
Author(s):  
James E. Byers
Keyword(s):  
Climate Change ◽  
Current Knowledge ◽  
Global Climate ◽  
Ecological Communities ◽  
Vital Rates ◽  
Ecological Processes ◽  
Performance Curves ◽  
Temperature Climate ◽  
Induced Changes ◽  
Host Parasite

Climate change affects ecological processes and interactions, including parasitism. Because parasites are natural components of ecological systems, as well as agents of outbreak and disease-induced mortality, it is important to summarize current knowledge of the sensitivity of parasites to climate and identify how to better predict their responses to it. This need is particularly great in marine systems, where the responses of parasites to climate variables are less well studied than those in other biomes. As examples of climate's influence on parasitism increase, they enable generalizations of expected responses as well as insight into useful study approaches, such as thermal performance curves that compare the vital rates of hosts and parasites when exposed to several temperatures across a gradient. For parasites not killed by rising temperatures, some simple physiological rules, including the tendency of temperature to increase the metabolism of ectotherms and increase oxygen stress on hosts, suggest that parasites’ intensity and pathologies might increase. In addition to temperature, climate-induced changes in dissolved oxygen, ocean acidity, salinity, and host and parasite distributions also affect parasitism and disease, but these factors are much less studied. Finally, because parasites are constituents of ecological communities, we must consider indirect and secondary effects stemming from climate-induced changes in host–parasite interactions, which may not be evident if these interactions are studied in isolation.

scholarly journals Drivers of Avian Diversity and Abundance Across Gradients of Human Influence.

2021 ◽  
Author(s):  
Benjamin J. Padilla ◽  
Chris Sutherland
Keyword(s):  
Landscape Heterogeneity ◽  
Species Abundance ◽  
Habitat Modification ◽  
Individual Species ◽  
Avian Diversity ◽  
Human Influence ◽  
Sensitive Species ◽  
Landscape Modification ◽  
Driving Patterns ◽  
Abundance And Diversity

Abstract Context: Identifying factors driving patterns of species communities in heterogenous human-dominated landscapes remains elusive despite extensive research. Biodiversity is thought to decrease with habitat modification, as sensitive species are lost. Conversely, diversity has also been shown increase at moderate levels of landscape modification where greater habitat heterogeneity supports a diverse suite of species.Objectives: We explore patterns of avian and diversity and abundance in heterogenous landscapes using a novel integration of multiple dimensional gradients of human-mediated disturbance.Methods: We attempt to identify aspects of landscape heterogeneity driving patterns of avian diversity and abundance in agro-urban-rural systems. Specifically, we utilize an intuitive multi-dimensional gradient distinguishing between two axes of human-influence, variation in the built environment (hard - soft) and in agricultural development (green - brown). We use these as covariates in community N-mixture models to describe variation in species abundance and diversity.Results: Avian diversity was greatest in more heterogeneous regions of the landscape. Responses of individual species were variable, with sensitive species declining, while generalist species increased, leading to higher overall diversity in human-dominated regions. Conclusions: Species abundance and diversity is maximized in more heterogeneous parts of landscape mosaics. By characterizing distinct axes of human influence that capture spectrum of land use, we can identify differential effects confounded in traditional landscape metrics. Critically, we demonstrate that multi-dimensional landscape gradients provide a more nuanced understanding of how patterns of biodiversity emerge. Acknowledging that biodiversity is not always negatively impacted by habitat disturbance offers encouraging insight to guide conservation and management in human-dominated landscapes.

scholarly journals Towards a Conceptual Understanding of Groundwater Ecology

2012 ◽  
Vol 1 (3) ◽  
pp. 493
Author(s):  
H.O Nwankwoala
Keyword(s):  
Conceptual Understanding ◽  
Chemical Properties ◽  
The Other ◽  
Ecological Communities ◽  
Groundwater Hydrology ◽  
Future Perspectives ◽  
Natural Ecosystems ◽  
Ecological Processes ◽  
Physico Chemical ◽  
Groundwater Ecology

In recent times, ecohydrology and hydroecology are making a mark on theenvironmental agenda, as evidenced by the proliferation of these terms in theacademic literature. There is an increasing recognition that groundwater is essentialto many ecological communities. Surface ecological processes (such asevapotranspiration) significantly impact hydrological responses and relatedhydrochemical function. Thus, the relation of groundwater hydrology to patternsand processes in ecology is a ‘two-way street’ where understanding the feedback ofone to the other serves as a powerful lens through which to evaluate and explainthe functioning of natural ecosystems. Influxes of groundwater to lakes, rivers, andwetlands can change whole-system physico-chemical properties such astemperature and salinity, while also providing more subtle influences onmicroenvironments and their ecological processes. The recognition of thesignificance and power of this tandem has not always been followed with effectiveinterdisciplinary science. The ecological, hydrological, and physico-chemical linksbetween groundwater, surface water and associated ecosystems are seldom fullyunderstood even though true characterization and wise management will require amultidisciplinary approach. This means biologists need to understand theimportance of magnitude and timing of groundwater flows for their system, whichrequires the skills of hydrogeologists to achieve. Hydrogeologists, in turn, mustunderstand how and why groundwater influences ecological processes so that theirexpertise is brought to bear at a scale commensurate to the ecological researchquestion. In this paper therefore, an overview of general concepts, research effortsand future perspectives are presented. More importantly, the paper asserts that it isnot simply the integration of hydrology and ecology that will determine the futureprospects for ecohydrology/hydroecology, but the way in which this integrativescience is conducted.

scholarly journals The proportion of core species in a community varies with spatial scale and environmental heterogeneity

2018 ◽  
Author(s):  
Molly F Jenkins ◽  
Ethan P White ◽  
Allen H Hurlbert
Keyword(s):  
Spatial Scale ◽  
Environmental Heterogeneity ◽  
Biotic Interactions ◽  
Bird Community ◽  
Species Variation ◽  
Ecological Communities ◽  
Transient Species ◽  
Ecological Processes ◽  
Core Species ◽  
Wide Range

Ecological communities are composed of a combination of core species that maintain local viable populations and transient species that occur infrequently due to dispersal from surrounding regions. Preliminary work indicates that while core and transient species are both commonly observed in community surveys of a wide range of taxonomic groups, their relative prevalence varies substantially from one community to another depending upon the spatial scale at which the community was characterized and its environmental context. We used a geographically extensive dataset of 968 bird community time series to quantitatively describe how the proportion of core species in a community varies with spatial scale and environmental heterogeneity. We found that the proportion of core species in an assemblage increased with spatial scale in a positive decelerating fashion with a concomitant decrease in the proportion of transient species. Variation in the shape of this scaling relationship between sites was related to regional environmental heterogeneity, with lower proportions of core species at a given scale associated with high environmental heterogeneity. This influence of scale and environmental heterogeneity on the proportion of core species may help resolve discrepancies between studies of biotic interactions, resource availability, and mass effects conducted at different scales, because the importance of these and other ecological processes are expected to differ substantially between core and transient species.

Occurrence of kleptoparasitic sarcophagid flies (Diptera: Sarcophagidae: Miltogramminae) in natural and human modified sites in Southern South American Andean landscapes

2021 ◽  
Vol 80 (3) ◽  
pp. 1-12
Author(s):  
Pablo R. Mulieri ◽  
Luciano D. Patitucci ◽  
Matías I. Dufek
Keyword(s):  
South America ◽  
Capture Rate ◽  
South American ◽  
Human Influence ◽  
Natural Areas ◽  
Habitat Types ◽  
Patagonian Steppe ◽  
Valdivian Forest

Sarcophagid flies belonging to the subfamily Miltogramminae are mainly kleptoparasites of bees and solitary wasps. Twenty-six locations were surveyed to accomplish the first specific exploration on the diversity of Miltogramminae in southern Andean areas of South America. We evaluated changes in abundance, richness and composition among habitat types to establish the effect of anthropization on the Miltogramminae community. Habitat types were considered as human modified (trails and roads, parks and meadows) and natural sites (watercourses and lake beaches, sandy and shrubby areas), distributed in two ecoregions (Valdivian forest and Patagonian steppe). We found differences in the capture rate and composition of Miltogramminae among habitat types. The species Opsidia intonsa Aldrich was highly dominant in samples, with higher proportional abundance in human modified habitats. Richness of Miltogramminae was higher in natural sites. Comparisons between the ecoregions surveyed indicated the genus Opsidia Coquillett did not show differences in abundance between ecoregions, whereas Senotainia Macquart was more abundant in the Patagonian steppe. The results provide evidence on the significant effects of human influence on landscapes in kleptoparasitic fly diversity. Slight modifications of natural areas (as proliferation of trails or isolated houses) should be addressed to evaluate the conservation of kleptoparasitic Diptera.

scholarly journals Effects of rapid evolution on species coexistence

2019 ◽  
Vol 116 (6) ◽  
pp. 2112-2117 ◽  
Author(s):  
Simon P. Hart ◽  
Martin M. Turcotte ◽  
Jonathan M. Levine
Keyword(s):  
Population Dynamics ◽  
Species Diversity ◽  
Interspecific Competition ◽  
Species Coexistence ◽  
Rapid Evolution ◽  
Empirical Work ◽  
Niche Differentiation ◽  
Ecological Communities ◽  
Competing Species ◽  
Ecological Processes

Increasing evidence for rapid evolution suggests that the maintenance of species diversity in ecological communities may be influenced by more than purely ecological processes. Classic theory shows that interspecific competition may select for traits that increase niche differentiation, weakening competition and thus promoting species coexistence. While empirical work has demonstrated trait evolution in response to competition, if and how evolution affects the dynamics of the competing species—the key step for completing the required eco-evolutionary feedback—has been difficult to resolve. Here, we show that evolution in response to interspecific competition feeds back to change the course of competitive population dynamics of aquatic plant species over 10–15 generations in the field. By manipulating selection imposed by heterospecific competitors in experimental ponds, we demonstrate that (i) interspecific competition drives rapid genotypic change, and (ii) this evolutionary change in one competitor, while not changing the coexistence outcome, causes the population trajectories of the two competing species to converge. In contrast to the common expectation that interspecific competition should drive the evolution of niche differentiation, our results suggest that genotypic evolution resulted in phenotypic changes that altered population dynamics by affecting the competitive hierarchy. This result is consistent with theory suggesting that competition for essential resources can limit opportunities for the evolution of niche differentiation. Our finding that rapid evolution regulates the dynamics of competing species suggests that ecosystems may rely on continuous feedbacks between ecology and evolution to maintain species diversity.

scholarly journals Metabolic theory and taxonomic identity predict nutrient recycling in a diverse food web

2015 ◽  
Vol 112 (20) ◽  
pp. E2640-E2647 ◽  
Author(s):  
Jacob Edward Allgeier ◽  
Seth J. Wenger ◽  
Amy D. Rosemond ◽  
Daniel E. Schindler ◽  
Craig A. Layman
Keyword(s):  
Body Mass ◽  
Nutrient Dynamics ◽  
Trophic Position ◽  
Ecological Communities ◽  
Metabolic Theory ◽  
Species Identity ◽  
Ecological Processes ◽  
Theoretical Approaches ◽  
Flow Through ◽  
Excretion Rates

Reconciling the degree to which ecological processes are generalizable among taxa and ecosystems, or contingent on the identity of interacting species, remains a critical challenge in ecology. Ecological stoichiometry (EST) and metabolic theory of ecology (MTE) are theoretical approaches used to evaluate how consumers mediate nutrient dynamics and energy flow through ecosystems. Recent theoretical work has explored the utility of these theories, but empirical tests in species-rich ecological communities remain scarce. Here we use an unprecedented dataset collected from fishes and dominant invertebrates (n = 900) in a diverse subtropical coastal marine community (50 families, 72 genera, 102 species; body mass range: 0.04–2,597 g) to test the utility of EST and MTE in predicting excretion rates of nitrogen (EN), phosphorus (EP), and their ratio (ENP). Body mass explained a large amount of the variation in EN and EP but not ENP. Strong evidence in support of the MTE 3/4 allometric scaling coefficient was found for EP, and for EN only after accounting for variation in excretion rates among taxa. In all cases, including taxonomy in models substantially improved model performance, highlighting the importance of species identity for this ecosystem function. Body nutrient content and trophic position explained little of the variation in EN, EP, or ENP, indicating limited applicability of basic predictors of EST. These results highlight the overriding importance of MTE for predicting nutrient flow through organisms, but emphasize that these relationships still fall short of explaining the unique effects certain species can have on ecological processes.

scholarly journals Research objectives in South African national parks

Koedoe ◽  
1977 ◽  
Vol 20 (2) ◽  
Author(s):  
U. De V Pienaar
Keyword(s):  
South African ◽  
National Parks ◽  
National Park ◽  
National Park Service ◽  
Plant Succession ◽  
Natural Areas ◽  
Ecological Processes ◽  
Park Service ◽  
Natural Regulation

The primary purpose of any national park service in administering natural areas is to maintain an area’s ecosystems in as nearly pristine a condition as possible. This means that ecological processes, including plant succession and the natural regulation of animal numbers, should be permitted to proceed as far as possible as they did under pristine conditions, and that modern man must be restricted to generally non-consumptive uses of these areas (Houston 1971).

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