scholarly journals Climate change in size-structured ecosystems

2012 ◽  
Vol 367 (1605) ◽  
pp. 2903-2912 ◽  
Author(s):  
Ulrich Brose ◽  
Jennifer A. Dunne ◽  
Jose M. Montoya ◽  
Owen L. Petchey ◽  
Florian D. Schneider ◽  
...  

One important aspect of climate change is the increase in average temperature, which will not only have direct physiological effects on all species but also indirectly modifies abundances, interaction strengths, food-web topologies, community stability and functioning. In this theme issue, we highlight a novel pathway through which warming indirectly affects ecological communities: by changing their size structure (i.e. the body-size distributions). Warming can shift these distributions towards dominance of small- over large-bodied species. The conceptual, theoretical and empirical research described in this issue, in sum, suggests that effects of temperature may be dominated by changes in size structure, with relatively weak direct effects. For example, temperature effects via size structure have implications for top-down and bottom-up control in ecosystems and may ultimately yield novel communities. Moreover, scaling up effects of temperature and body size from physiology to the levels of populations, communities and ecosystems may provide a crucially important mechanistic approach for forecasting future consequences of global warming.

Author(s):  
Janne I. Kaariainen ◽  
Brian J. Bett

The benthic body size miniaturization hypothesis states that deep-sea communities are dominated by organisms of smaller body size, although some field studies have produced contradictory results. Using appropriate sample sets, this study tests this hypothesis by contrasting the benthic communities of the Fladen Ground (North Sea, 150 m) and the Faroe–Shetland Channel (1600 m). Samples were collected for large (500 μm) and small macrofauna (250–355 μm), meiofauna (45 μm) as well as an intermediate sized ‘mesofauna’ (180 μm) to ensure comprehensive coverage of the full meio- and macro-faunal body size-range. The body size structure of the benthos was compared using two methods. The more widely used average individual biomass method involves dividing the total sample biomass by sample abundance. Additionally, body size accumulation curves were constructed by assigning all specimens into a logarithmic size-class and then plotting the cumulative percentage of individuals present in each size-class. The results seem to support the hypothesis that the deep-sea environment is a small organism habitat. Although these findings only represent two locations, the overall body size accumulation curves clearly display a statistically significant shift towards smaller body sizes at the deeper site. The magnitude of the effect is appreciable with median metazoan body size reducing from 14.3 μg wet weight in the Fladen Ground to 3.8 μg wet weight in the Faroe–Shetland Channel. The average individual biomass measurements are shown to be of limited value and can lead to potentially misleading conclusions if the underlying size structure is not analysed in detail.


Author(s):  
John R Beaver ◽  
Claudia E Tausz ◽  
Katherine M Black ◽  
Benjamin A Bolam

Abstract Body size is an important functional trait that can be indicative of ecosystem structure and constraints on growth. Both increasing temperatures and eutrophication of lakes have been associated with a shift toward smaller zooplankton taxa. This is important in the context of climate change, as most aquatic habitats are expected to warm over the coming decades. Our study uses data from over 1000 lakes surveyed across a range of latitudes (26–49°N) and surface temperatures (10–35°C) in the USA during the spring/summer of 2012 to characterize pelagic cladoceran body size distributions. We used univariate and multiple regression modeling to determine which environmental parameters were strongly correlated to cladoceran body size. A strong positive correlation was observed between cladoceran body size and latitude, while a strong negative correlation was observed between cladoceran body size and water temperature. The ratio of zooplankton to phytoplankton, as well as relative total biomass contributions by cladocerans, decreased as trophic state increased. Multiple regression identified temperature-related variables and water clarity as significantly affecting cladoceran body size. These observations demonstrate the dual threat of climate change and eutrophication on lake ecosystems and highlight potential changes in biogeographical patterns of zooplankton as lakes warm.


2012 ◽  
Vol 367 (1605) ◽  
pp. 3042-3049 ◽  
Author(s):  
Giselle Perdomo ◽  
Paul Sunnucks ◽  
Ross M. Thompson

There is a clear crisis in the maintenance of biodiversity. It has been generated by a multitude of factors, notably habitat loss, now compounded by the effects of climate change. Predicted changes in climate include increased severity and frequency of extreme climatic events. To manage landscapes, an understanding of the processes that allow recovery from these extreme events is required. Understanding these landscape-scale processes of community assembly and disassembly is hindered by the large scales at which they operate. Model systems provide a means of studying landscape scale processes at tractable scales. Here, we assess the combined effects of temperature and habitat-patch isolation on assembly of naturally diverse moss microarthropod communities after a high-temperature event. We show that community assembly depends on temperature and on degree of habitat isolation. Heated communities were heavily dominated in abundance by two species, one of them relatively large. The resulting size-structure is unlike that seen in the field. Community composition in habitat fragments appears also to have been influenced by the source pool of recolonizing fauna. Our results highlight the value of dispersal in disturbed landscapes and the potential for habitat connectivity to buffer communities from the effects of climate change.


2021 ◽  
pp. 417-452
Author(s):  
Paul Schmid-Hempel

Host ecological characteristics, such as body size, longevity, or social living, affect parasitism. Host populations can be regulated in size by their parasites; they can even drive host populations to extinction, usually after hosts have been weakened by other factors. Parasites, therefore, threaten endangered populations and species. Parasites also affect host ecological communities and food webs via effects on competitive ability or with apparent competition. In diverse host communities, infectious diseases become ‘diluted’. Parasite ecological communities seem to have a variable and transient structure; no universal explanation for the observed patterns exists. Host migration can transfer parasites to new areas or leave parasites behind. Disease emergence from an animal reservoir (zoonoses) is especially important. Many human diseases have such an origin, and these have repeatedly caused major epidemics. Climate change will also affect parasitism; however, the direction of change is rather complex and depends on the particular systems.


2017 ◽  
Vol 284 (1860) ◽  
pp. 20170357 ◽  
Author(s):  
Rafał Nawrot ◽  
Paolo G. Albano ◽  
Devapriya Chattopadhyay ◽  
Martin Zuschin

Body size is a synthetic functional trait determining many key ecosystem properties. Reduction in average body size has been suggested as one of the universal responses to global warming in aquatic ecosystems. Climate change, however, coincides with human-enhanced dispersal of alien species and can facilitate their establishment. We address effects of species introductions on the size structure of recipient communities using data on Red Sea bivalves entering the Mediterranean Sea through the Suez Canal. We show that the invasion leads to increase in median body size of the Mediterranean assemblage. Alien species are significantly larger than native Mediterranean bivalves, even though they represent a random subset of the Red Sea species with respect to body size. The observed patterns result primarily from the differences in the taxonomic composition and body-size distributions of the source and recipient species pools. In contrast to the expectations based on the general temperature–size relationships in marine ectotherms, continued warming of the Mediterranean Sea indirectly leads to an increase in the proportion of large-bodied species in bivalve assemblages by accelerating the entry and spread of tropical aliens. These results underscore complex interactions between changing climate and species invasions in driving functional shifts in marine ecosystems.


2005 ◽  
Vol 56 (1) ◽  
pp. 1 ◽  
Author(s):  
B. J. Robson ◽  
L. A. Barmuta ◽  
P. G. Fairweather

Benthic ecologists have studied the distribution of animal body sizes because it is a form of ‘taxon-free’ classification that may be a useful metric for describing variation within and between ecological communities. In particular, the idea that the allometry of physiological and life-history traits may control species composition and relative abundances implies a functional link between body-size distributions and communities. The physical structure of aquatic habitats has often been cited as the mechanism by which habitat may determine body-size distributions in communities. However, further progress is hindered by a lack of theoretical clarity regarding the mechanisms that connect body size to the characteristics of ecological communities, leading to methods that may obscure interesting trends in body-size data. This review examines the methodological and conceptual issues hindering progress in the search for a relationship between animal body size and habitat architecture and suggests ways to resolve these issues. Problems are identified with current methods for the measurement of animal body size, the data and measures used to quantify body-size distributions and the methods used to identify patterns therein. Fundamentally, renewed emphasis on the mechanisms by which animal body sizes are influenced by habitat architecture is required to refine methodology and synthesise results from pattern-seeking and mechanistic studies.


2015 ◽  
Vol 162 (3) ◽  
pp. 675-685 ◽  
Author(s):  
Serena Donadi ◽  
Britas Klemens Eriksson ◽  
Karsten Alexander Lettmann ◽  
Dorothee Hodapp ◽  
Jörg-Olaf Wolff ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manoela C. Brandão ◽  
Fabio Benedetti ◽  
Séverine Martini ◽  
Yawouvi Dodji Soviadan ◽  
Jean-Olivier Irisson ◽  
...  

AbstractOcean plankton comprise organisms from viruses to fish larvae that are fundamental to ecosystem functioning and the provision of marine services such as fisheries and CO2 sequestration. The latter services are partly governed by variations in plankton community composition and the expression of traits such as body size at community-level. While community assembly has been thoroughly studied for the smaller end of the plankton size spectrum, the larger end comprises ectotherms that are often studied at the species, or group-level, rather than as communities. The body size of marine ectotherms decreases with temperature, but controls on community-level traits remain elusive, hindering the predictability of marine services provision. Here, we leverage Tara Oceans datasets to determine how zooplankton community composition and size structure varies with latitude, temperature and productivity-related covariates in the global surface ocean. Zooplankton abundance and median size decreased towards warmer and less productive environments, as a result of changes in copepod composition. However, some clades displayed the opposite relationships, which may be ascribed to alternative feeding strategies. Given that climate models predict increasingly warmed and stratified oceans, our findings suggest that zooplankton communities will shift towards smaller organisms which might weaken their contribution to the biological carbon pump.


2012 ◽  
Vol 28 (2) ◽  
Author(s):  
Irma Gisela Nieto-Castañeda ◽  
Saías Hazarmabeth Salgadougarte ◽  
María Luisa Jiménez-Jiménez

We studied the life cycle of the spider Syspira tigrina (Araneae: Miturgidae) by indirect methods. This species is endemic to the North American deserts and locally abundant; nevertheless, information on its biology is scarce. We did monthly collections for over a year at La Paz, Baja California Sur, Mexico. We found that adult spiders were more abundant between August and November 2005 and had low abundance or were absent the remainder of the year while juveniles were present all year. To estimate changing body size structure of the population we analyzed juvenile tibia I length distribution (TIL) (as indicator of the body size) of each monthly sample by means of Kernel Density Estimators (KDEs). We found 35 TIL juveniles size groups (Gaussian components). The smallest juveniles were more abundant between October 2005 and January 2006 and the biggest were more abundant twice during the hottest months. We hypothesize that mating period is between August and October 2005 and the main recruitment period from November 2005 and January 2006. However we found evidenceof continuous recruitment through the year, suggesting that although there is a peak of reproduction in November, the females oviposit almost all year. Also there is evidence of juveniles’ growth pattern from January to July 2006. The use of KDEs with histograms is a very good statistical tool to delimit size groups with mixed frequency distributions that otherwise might be difficult. This tool should be useful to test any hypothesis related with the body size structure of a population or community.


2018 ◽  
Author(s):  
Jasmijn Hillaert ◽  
Thomas Hovestadt ◽  
Martijn L. Vandegehuchte ◽  
Dries Bonte

AbstractBody size is a fundamental trait known to allometrically scale with metabolic rate, and therefore a key determinant of individual development, life history and consequently fitness. In spatially structured environments, movement is an equally important driver of fitness. Because movement is tightly coupled with body size, we expect habitat fragmentation to induce a strong selection pressure on size variation across and within species. Changes in body size distributions are then, in turn, expected to alter food web dynamics. However, no consensus has been reached on how spatial isolation and resource growth affect body size distributions.Our aim was to investigate how these two factors shape the body size distribution of consumers under scenarios of size-dependent and -independent consumer movement by applying a mechanistic, individual-based resource-consumer model. The outcome was then linked to important ecosystem traits such as resource abundance and stability. Finally, we determined those factors that explain most variation in size distributions.We demonstrate that decreasing connectivity and resource growth select for communities (or populations) consisting of larger species (or individuals) due to strong selection for the ability to move over longer distances. When including size-dependent movement, moderate levels of connectivity result in increases in local size diversity. Due to this elevated functional diversity, resource uptake is optimized at the metapopulation or metacommunity level. At these intermediate levels of connectivity, size-dependent movement explains most of the observed variation in size distributions. Interestingly, local and spatial stability of consumer biomass are lowest when isolation and resource productivity are high. Finally, we highlight that size-dependent movement is of vital importance for the survival of populations within highly fragmented landscapes. Our results demonstrate that considering size-dependent movement and resource growth is essential to understand patterns of size distributions at the population or community level and the resulting metapopulation or metacommunity dynamics.


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