scholarly journals Tropical fish diversity enhances coral reef functioning across multiple scales

2019 ◽  
Vol 5 (3) ◽  
pp. eaav6420 ◽  
Author(s):  
Jonathan S. Lefcheck ◽  
Anne A. Innes-Gold ◽  
Simon J. Brandl ◽  
Robert S. Steneck ◽  
Ruben E. Torres ◽  
...  

There is now a general consensus that biodiversity positively affects ecosystem functioning. This consensus, however, stems largely from small-scale experiments, raising the question of whether diversity effects operate at multiple spatial scales and flow on to affect ecosystem structure in nature. Here, we quantified rates of fish herbivory on algal turf communities across multiple coral reefs spanning >1000 km of coastline in the Dominican Republic. We show that mass-standardized herbivory rates are best predicted by herbivore biomass and herbivore species richness both within (α-diversity) and across sites in the region (β-diversity). Using species-diversity models, we demonstrate that many common grazer species are necessary to maximize the process of herbivory. Last, we link higher herbivory rates to reduced algal turf height and enhanced juvenile coral recruitment throughout the ecosystem. Our results suggest that, in addition to high herbivore biomass, conserving biodiversity at multiple scales is important for sustaining coral reef function.

2019 ◽  
Vol 7 ◽  
Author(s):  
Jonathan S. Lefcheck ◽  
Simon J. Brandl ◽  
Anne A. Innes-Gold ◽  
Robert S. Steneck ◽  
Ruben E. Torres ◽  
...  

2019 ◽  
Author(s):  
Jesse Miller ◽  
Hugh Safford

Ecological disturbance is a major driver of ecosystem structure and evolutionary selection, and theory predicts that disturbance frequency and / or intensity should determine its effects on communities. However, adaptations of species pools to different historical disturbance regimes are rarely considered in the search for generalizable community responses to disturbance. To explore how disturbance severity affects plant diversity patterns, we review studies of understory plant community responses to wildfire in conifer forests of western North America across a gradient of departure from historical fire regimes. We find that post-fire plant species richness may generally be maximized at disturbance severities that match the predominant historical disturbance regime in a given ecosystem. Studies that examined multiple spatial scales indicate that plant community responses to fire are likely to be scale-dependent, suggesting that post-disturbance monitoring should consider community responses at multiple scales. Our review highlights that considering adaptations to historical disturbance regimes may improve the ability to predict disturbance effects on communities. We discuss future research needs; quantitative studies that compare community responses to fire at multiple scales across different historical fire regimes would be particularly useful. Ultimately, considering disturbance as a multivariate problem is likely to lead to greater inference than traditional bivariate approaches.


1999 ◽  
Vol 56 (S1) ◽  
pp. 52-60 ◽  
Author(s):  
Timothy E Essington ◽  
James F Kitchell

Analyses of fish distributions rarely account for spatial arrangement of habitat types, are typically conducted at a single scale, and use a null model of random distributions without considering other null models. This study demonstrates a procedure to circumvent these difficulties by analyzing telemetry data collected on largemouth bass (Micropterus salmoides) in Long Lake, Michigan. Bass were highly aggregated within the littoral region, showing peaks of aggregation at small (<60 m) and large (>160 m) spatial scales. A neutral movement model (no taxis or kinesis within habitat types) could explain some of the observed aggregation, yet substantial aggregation remains unexplained. Much of the large-scale aggregation could be generated by including a taxis towards the eastern half of the basin, but taxes towards shallower cells or cells containing woody emergent macrophytes were unable to generate the observed degree of small-scale aggregation. Our results highlight the utility of analyzing spatial distributions at multiple scales and the importance of the spatial arrangements of habitat types and suggest that nonrandom distributions at one scale may be due to processes occurring at different scales.


2007 ◽  
Vol 158 (8) ◽  
pp. 235-242 ◽  
Author(s):  
Hans Rudolf Heinimann

The term «precision forestry» was first introduced and discussed at a conference in 2001. The aims of this paper are to explore the scientific roots of the precision concept, define «precision forestry», and sketch the challenges that the implementation of this new concept may present to practitioners, educators, and researchers. The term «precision» does not mean accuracy on a small scale, but instead refers to the concurrent coordination and control of processes at spatial scales between 1 m and 100 km. Precision strives for an automatic control of processes. Precision land use differs from precision engineering by the requirements of gathering,storing and managing spatio-temporal variability of site and vegetation parameters. Practitioners will be facing the challenge of designing holistic, standardized business processes that are valid for whole networks of firms,and that follow available standards (e.g., SCOR, WoodX). There is a need to educate and train forestry professionals in the areas of business process re-engineering, computer supported management of business transactions,methods of remote sensing, sensor technology and control theory. Researchers will face the challenge of integrating plant physiology, soil physics and production sciences and solving the supply chain coordination problem (SCCP).


EcoHealth ◽  
2021 ◽  
Author(s):  
Felipe A. Hernández ◽  
Amanda N. Carr ◽  
Michael P. Milleson ◽  
Hunter R. Merrill ◽  
Michael L. Avery ◽  
...  

AbstractWe investigated the landscape epidemiology of a globally distributed mammal, the wild pig (Sus scrofa), in Florida (U.S.), where it is considered an invasive species and reservoir to pathogens that impact the health of people, domestic animals, and wildlife. Specifically, we tested the hypothesis that two commonly cited factors in disease transmission, connectivity among populations and abundant resources, would increase the likelihood of exposure to both pseudorabies virus (PrV) and Brucella spp. (bacterial agent of brucellosis) in wild pigs across the Kissimmee Valley of Florida. Using DNA from 348 wild pigs and sera from 320 individuals at 24 sites, we employed population genetic techniques to infer individual dispersal, and an Akaike information criterion framework to compare candidate logistic regression models that incorporated both dispersal and land cover composition. Our findings suggested that recent dispersal conferred higher odds of exposure to PrV, but not Brucella spp., among wild pigs throughout the Kissimmee Valley region. Odds of exposure also increased in association with agriculture and open canopy pine, prairie, and scrub habitats, likely because of highly localized resources within those land cover types. Because the effect of open canopy on PrV exposure reversed when agricultural cover was available, we suggest that small-scale resource distribution may be more important than overall resource abundance. Our results underscore the importance of studying and managing disease dynamics through multiple processes and spatial scales, particularly for non-native pathogens that threaten wildlife conservation, economy, and public health.


2016 ◽  
Vol 15 (1) ◽  
pp. 96
Author(s):  
E. Iglesias-Rodríguez ◽  
M. E. Cruz ◽  
J. Bravo-Castillero ◽  
R. Guinovart-Díaz ◽  
R. Rodríguez-Ramos ◽  
...  

Heterogeneous media with multiple spatial scales are finding increased importance in engineering. An example might be a large scale, otherwise homogeneous medium filled with dispersed small-scale particles that form aggregate structures at an intermediate scale. The objective in this paper is to formulate the strong-form Fourier heat conduction equation for such media using the method of reiterated homogenization. The phases are assumed to have a perfect thermal contact at the interface. The ratio of two successive length scales of the medium is a constant small parameter ε. The method is an up-scaling procedure that writes the temperature field as an asymptotic multiple-scale expansion in powers of the small parameter ε . The technique leads to two pairs of local and homogenized equations, linked by effective coefficients. In this manner the medium behavior at the smallest scales is seen to affect the macroscale behavior, which is the main interest in engineering. To facilitate the physical understanding of the formulation, an analytical solution is obtained for the heat conduction equation in a functionally graded material (FGM). The approach presented here may serve as a basis for future efforts to numerically compute effective properties of heterogeneous media with multiple spatial scales.


Author(s):  
Alessandra R. Kortz ◽  
Anne E. Magurran

AbstractHow do invasive species change native biodiversity? One reason why this long-standing question remains challenging to answer could be because the main focus of the invasion literature has been on shifts in species richness (a measure of α-diversity). As the underlying components of community structure—intraspecific aggregation, interspecific density and the species abundance distribution (SAD)—are potentially impacted in different ways during invasion, trends in species richness provide only limited insight into the mechanisms leading to biodiversity change. In addition, these impacts can be manifested in distinct ways at different spatial scales. Here we take advantage of the new Measurement of Biodiversity (MoB) framework to reanalyse data collected in an invasion front in the Brazilian Cerrado biodiversity hotspot. We show that, by using the MoB multi-scale approach, we are able to link reductions in species richness in invaded sites to restructuring in the SAD. This restructuring takes the form of lower evenness in sites invaded by pines relative to sites without pines. Shifts in aggregation also occur. There is a clear signature of spatial scale in biodiversity change linked to the presence of an invasive species. These results demonstrate how the MoB approach can play an important role in helping invasion ecologists, field biologists and conservation managers move towards a more mechanistic approach to detecting and interpreting changes in ecological systems following invasion.


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