Other Oral Presentations
New Indices for Ranking Locations for Conserving Biodiversity.
Honorary Professor Gee Coleman
8th International Temperate Reefs Conference, University of Adelaid, Australia
2009
Aggregation does not alter the desiccation status in an intertidal limpet.
Associate Professor Ross Coleman
8th International Temperate Reefs Symposium, University of Adelaide, Australia
2009
One of the most common reasons invoked for patterns of distribution of animals in the rocky intertidal is physiological constraint; that animals live in certain places because their physiology dictates this. This explanation has been put forward for different scales of animal distribution from macroecological dimensions to microscale distributions, including for aggregation behaviours. For intertidal limpets, a common explanation for aggregation is a reduction in desiccation risk. There is no good published evidence for this. By manipulating the relative aggregation status of individual limpets, I show that aggregation in the limpet Cellana tramoserica makes no difference to the desiccation status of individual limpets and that this pattern is consistent in time/space. Not only does this demonstrate that one model for why limpets form aggregations is not correct, but also has implications for our understanding of the response of animals to changing climatic conditions; increased temperature and hence desiccation risk may not change patterns of aggregation
A conceptual framework to study the effects of habitat structure on diversity of benthic assemblages.
Matias, M.G., Underwood, A.J., Coleman, R.A. & Hochuli, D.F.
94th Ecological Society of America Annual Meeting, Albuquerque, New Mexico.
2-7 August, 2009
Water Depth and Foraging of Black-Winged Stilts Himantopus himantopus.
Coleman, R.A., Forsyth, K. and Chapman M.G.
British Ecological Society Annual Meeting, University of Hertfordshire, Hatfield, UK.
2009
It is widely held assumed that water depth modifies the foraging of wading birds, yet this has not been tested. By manipulating the water depth in a lagoon used by a population of black winged stilts Himantopus himantopus, we show that making the water deeper changes feeding behaviour but decreasing depth does not. Potential mechanisms for this are discussed
Lundy Island No Take Zone – The First Five Years. Coastal Futures
Hoskin, M.G., Davis. C., Coleman, R.A.
Review and Future Trends, SOAS, University of London, UK
2008
Food supply and foraging behaviour: Attacks by oystercatchers on aggregated prey.
Associate Professor Ross Coleman
35th Annual Meeting of the Australasian Society for the Study of Animal Behaviour, Coffs Harbour, University of New England, Australia
2008
Know your prey: The foraging response of oystercatchers when prey availability varies independently from abundance.
Birdsey, E.M. & Coleman, R.A.
35th Annual Meeting of the Australasian Society for the Study of Animal Behaviour, Coffs Harbour, University of New England, Australia
2008
Refuting the Drying-out Hypothesis: Aggregation does not alter the desiccation status in an intertidal limpet.
Associate Professor Ross Coleman
British Ecological Society Annual Meeting, Imperial College, London.
2008
Coastal development affects diversity and ecological processes of kelp epifauna.
Marzinelli, E. M., Coleman R.A, Underwood A.J. Blockley, D.J.
World Conference on Marine Biodiversity, Valencia, Spain
2008
Changes in management of an urban coastal lagoon and ecological consequences for birds.
Associate Professor Ross Coleman
Ecological Society of Australia Annual Meeting, University of Sydney, Australia
2008
Restoration of habitats requires two things. First, a quantitative understanding of existing ecological conditions and second, a statement of the desired ecological outcomes of the completion of restoration. The long-term management of the Waterbird Refuge (WBR) at the Sydney Olympic Park (NSW, Australia) included increasing the diversity and number of birds utilising the WBR and so the WBR was drained and tidal flushing increased via a ‘SmartGate’. This project evaluated the WBR in respect of wading birds and their food under current conditions. Microalgal abundance was examined using chlorophyll density as a surrogate measure. This was variable between the three locations chosen (two control and the WBR) but most importantly, was very variable at the scale of 10's of centimetres. Within the WBR, the macrofaunal was examined as an estimate of available food for wading birds. This showed that the total assemblage variation between sites (10's of metres) was less than that at a smaller scale, that of centimetres. The assemblage macrofaunal encountered was very different from controls before the ‘SmartGate' was installed. The wading bird assemblage noted as feeding at the WBR were dominated by Recurvirostra novahollandiae and Himantopus himantopus, however location of feeding activities did not change. From this three-year study, it is clear that the ecological conditions of the WBR and are now very different. The number and diversity of wading birds has increased and the management of the WBR has solved a significant local problem.
The effects of changing diversity of species on temporal variability: an experimental test with intertidal assemblages of grazing gastropods and epilithic algae.
P. Range
42nd European Marine Biology Symposium, Kiel, Germany
27-31st August, 2007
Long-standing controversies in community ecology are whether and how species diversity is related to stability (the diversity-stability debate). Widespread concerns about anthropogenic disturbances to natural systems, in particular the perception of increasing rates of extinction of species, has motivated more recent interest on this issue. It is generally proposed that the loss of diversity (usually expressed as loss of species) increases the temporal variability of ecological proprieties and processes. Temporal variability at the population-level does not seem to conform to the same general pattern; it has been found to be unaffected or to decrease with decreasing number of species. In the experiment described here, densities of the limpet Cellana tramoserica were manipulated, using barriers of copper-based antifouling paint to create exclosure and enclosure treatments on the rocky shore. Densities of other gastropods, intensity of grazing (proportion of area grazed on wax discs) and biomass of epilithic algae (Chlorophyll extractions, colour-infrared photography and confocal microscopy) were measured regularly during one year in these manipulated areas and in control areas with natural densities of limpets. Different approaches were used to estimate temporal variability for these variables, none of which requires assumptions about the existence of states of equilibrium. Results are interpreted in relation to some of the underlying mechanisms commonly used to explain diversity-stability relationships, such as “statistical averaging” (or “portfolio effect”) and the “insurance hypothesis”.
Testing the effects of substratum heterogeneity and complexity on the abundance and distribution of hydroids
Carolina J. Zagal
Benthic Ecology Meeting (BEM), Georgia Tech, Atlanta, USA
March 21st – March 24th, 2007
Artificial plant units (APUs) were used to evaluate the effects of heterogeneity and complexity of the substratum on the abundance and distribution of hydroids. It was predicted that covers of hydroids are greater on middle and peripheral parts of kelp because these zones are more: (1) rugose; (2) bushy; (3) rugose and bushy; (4) rugose or bushy. APUs with different levels of heterogeneity (smooth, Sm or rugose, Ru) and complexity (simple, Si or bushy, Bu) were used to test the following specific hypotheses from these models: covers of hydroids will be greater on APUs which are: (H1) rugose (RuSi and RuBu) than smooth (SmSi and SmBu) and covers on the periphery (P) and centre (C) will not differ; (H2) bushy (SmBu and RuBu) than simple (SmSi and RuSi), and covers will be greater on P than on C; (H3) rugose and bushy (RuBu) than others (SmSi, SmBu, RuSi) and covers will be greater on P than on C; (H4) rugose or bushy (RuBu, RuSi and SmBu) than smooth and simple ones (SmSi). Covers of hydroids were significantly greater on bushy treatments than simple ones and on the periphery than the centre of all treatments, supporting the second model (bushiness increases abundance). This may be partly explained by rugosity on the periphery of kelp plants, but the scales of heterogeneity used in this study do not, on their own, explain the observed patterns.
Small-scale variation in environment and responses to climatic change
A. C. Jackson, A. J. Underwood, G. A. Skilleter
Change in Aquatic Ecosystems: Natural and Human Influences, Marine Biological Association UK, University of Plymouth, Scottish Association for Marine Science, Freswater Biological Association UK, Plymouth, UK
4-6 July 2007
Examples of global climatic changes affecting coastal biodiversity caused by are increasingly apparent from manipulative experiments and analyses of long-term datasets. Components of climatic change likely to be of importance for intertidal animals are: rises in sea-level, increases in temperature (in air and water) and increased frequency of storm events. Changes to biodiversity are expected to occur in the form of shifts of species to new geographic locations and habitats. There is increasing interest in understanding why and predicting how this might happen.
Distributions of mobile animals are influenced by variables that can act, as for insolation, directly (e.g. through heat or desiccation stress) or indirectly (by reducing the availability of algal food). Animals respond to cues at small scales and so small-scale variability in the environment may cause large variability in densities of organisms at small scales. Suggested changes in distribution (polewards with rising temperature; upshore with rising sea-level, increased reliance on shelter with larger waves), may not be possible, if suitable resources (e.g. habitat and food) are not available in the new locations. Without knowing how the small-scale environment varies and which aspects are most important, predictions cannot be made about how distributions of animals might alter under climatic change.
There are many well-known patterns of association of animals with small-scale topographic features but the actual causes of these associations are often assumed rather than tested. For instance, aggregations of gastropods in crevices are frequently assumed to be responding to reduced temperatures, greater humidities or reduced shear-stresses from water movements.
To make useful predictions about how distributions and densities of intertidal animals will be affected by climatic change we need to know, amongst other things
1) how topographic features currently alter conditions on the shore
2) how climatic change will affect these conditions
To solve these and other vital information gaps, we are using an experimental system that includes grazing and predatory gastropods that are widespread and abundant on rocky intertidal shores of the east coast of Australia. Under a range of climatic conditions (e.g. sub-tropical/temperate, summer/winter, wave-exposed/sheltered), we are measuring how natural and artificial crevices influence environmental variables such as temperature, relative humidity, wave impacts, and rates of water-flow. We are using novel, non-destructive imaging and field spectrometry to measure how crevices alter availability of food. Conditions in sub-tropical Brisbane, where temperatures are already greater, provide a basis for understanding future conditions in temperate Sydney.
This will allow us to understand better:
1) how environmental variables change at ecologically relevant scales;
2) the way in which conditions might change in Sydney.
This information will be combined with parallel experiments measuring availability and use of different topographic features under different conditions and those testing how environmental variables interact to influence small-scale distribution of animals. Predictions about how distributions of animals will change are currently made using assumptions about which variables are important for small-scale distributions. Preliminary results indicate that crevices provide conditions that differ greatly from other habitats, but these differences are not always as we might assume.
This research improves understanding of how topographic features influence environmental variables and consequently improves our predictive capacity about consequences of climatic change for coastal biodiversity and raises our understanding of how it can be conserved and managed.
Seaweeds fight back
R.A. Coleman
Sydney Harbour Week, Sydney Harbour Federation Trust Chowder Bay Open Day, Chowder Bay
4th March 2007
Linking functional diversity and non-random distribution of species to ecosystem functioning
M.G. Matias, F. Arenas, S. Vaselli and I.S. Pinto
42nd European Marine Biology Symposium, Kiel, Germany
27-31st August 2007
Most biodiversity experiments have used microcosms or mesocosms where diversity is manipulated by randomly choosing species and assembling them together. Spatial distribution of species in these synthetic assemblages is typically random. However, in natural assemblages, spatial distribution of plants and animals is in many cases non-random. Understanding whether this spatial distribution of species (i.e. patchiness) affects functioning of ecosystems characterized by patchy distributions (i.e. rockpools) is of major importance. In this study, we experimentally create synthetic assemblages by manipulating their diversity and patchiness. Three morpho-functional groups were used: (i) sub-canopy ; (ii) turf-forming and (iii) encrusting coralline algae. Each group was represented by several species, randomly selected among those most abundant in the available pool of species at the study region. Results are primarily discussed on the basis of morpho-functional differences between groups of seaweeds but also providing information about how these seaweeds influence their surroundings. Different access to available resources (e.g. free space, nutrients and light) is suggested to be determinant in influencing processes of synthetic assemblages.
Induction of chemical defences in response to browsing: Effects of artificial and natural browsing by introduced Rusa deer on the eucalypt Corymbia gummifera.
E. Kissler, R.A. Coleman & C. McArthur
Annual Meeting of the Ecological Society of America, San José, California, USA.
5-10th August, 2007
Human modification of habitat and its effect on kelp epifauna
E.M. Marzinelli, Dr D. Blockley, Professor A.J. Underwood & Associate Professor R. A. Coleman
42nd European Marine Biology Symposium, Kiel, Germany
27-31 August 2007
Degradation of natural habitat as a result of increasing urbanization is a substantial cause of the loss of biodiversity. In coastal waters surrounding cities, natural habitats are often replaced by artificial structures such as pier-pilings, jetties and seawalls. Epibiotic assemblages growing on blades of the kelp Ecklonia radiata differ between pilings and natural rocky reefs. In particular, the abundance of Bryozoa was much greater on kelp growing on pilings than on that growing on rocky reefs. This pattern was consistent at several locations in Sydney Harbour. This difference in abundances could be caused by differences in properties of the habitat (i.e. differences between pilings and rocky reefs) or by differences in the type of kelp found on each habitat (or both). We experimentally transplanted kelp from pilings to rocky reefs and from rocky reefs to pilings to test these models. This showed that properties of the habitat affect the abundance of Bryozoa, not the type of kelp that grows on pilings or rocky reefs. We tested models about the physical and biological factors that may differ between artificial and natural habitats that could affect the colonization of Bryozoa on kelp blades, such as shading and predation. The results of manipulative experiments to determine which processes underlie these patterns will be discussed.
Food supply and foraging behaviour: Attacks by oystercatchers on aggregated prey
R. A. Coleman, P.A. Cotton, E.M. Birdsey
42nd European Marine Biology Symposium, Kiel, Germany
27-31st August, 2007
On UK moderately exposed shores, groups of limpets (Patella vulgata)occur on the mid-shore, some of which may be due to past history of Fucus clumps but others are due to the tendency of limpets to group. This could be a response to oystercatcher (Haematopus ostralegus) predation which is seasonally variable and unpredictable in space and time. Previous work has shown that oystercatchers prefer solitary to grouped limpets and are more successful in predation attempts on singletons. It has also been demonstrated that an attack on one limpet in a group alerts the entire group, all of which then clamp down and become unavailable. We tested hypotheses that foraging oystercatchers treat a group as a single limpet and only attack one individual within a group and we also tested the hypothesis that birds will not attack another limpet near enough to be able to detect the previous attack.We show that oystercatchers attack one limpet in a group then move on to attack another individual limpet, and we also demonstrate that the distance they move is greater than the distance groups of limpets have been known to detect attacks. Thus in the oystercatcher-limpet predator prey system on rocky shores, groups of limpets are actually 1 prey item independently of the number of limpets in the group. This has implications for assessment of food supply for avian predators on rocky shores.
Ecological and fisheries effects of the Lundy No-Take Zone (Bristol Channel, UK). European Symposium on Marine Protected Areas as a Tool for Fisheries Management and Ecosystem Conservation
M.G. Hoskin, C. Davis, R. A. Coleman & K. Hiscock
European Symposium on Marine Protected Areas as a Tool for Fisheries Management and Ecosystem Conservation, Murcia, Spain
25-28th September 2007
Lundy is an island in the middle of the productive, tide-swept waters of the Bristol Channel in south west England. It supports diverse marine habitats and species including several that are a priority for conservation at both national and European levels. Lundy Island was designated under the Habitats Directive as a Special Area of Conservation in 1994. To enhance the protection Lundy’s marine life from potential impacts of commercial fishing and recreational harvesting, part of the island’s inshore waters were designated as a No-Take Zone (NTZ) in 2003. The Lundy NTZ occupies ~4 km2 and includes both rocky and sedimentary habitats. At present, this is the only statutory NTZ for nature conservation purposes in the UK. Since 2004, there has been detailed programme of annual monitoring to assess ecological and fisheries effects of the Lundy NTZ. Monitoring includes sampling of lobsters and crabs using baited pots and, in separate studies, diver-sampling of long-lived epifauna on subtidal rocky habitats and scallops on sedimentary habitats. Potential effects of the NTZ are assessed via comparisons with appropriate control locations where fishing continues. The potting study also includes larger-scale comparisons with locations in South Wales and North Devon. The monitoring programme is due for the completion of its first stage in the summer of 2007. We will be able to present the initial results of the monitoring programme for the first time at this conference. Initial results over the past 3 years have shown significant effects of the NTZ on some commercial species. We will present monitoring results to date and discuss the significance of Lundy in the context of the UK’s developing policies on NTZs and other forms of Marine Protected Area.
Critical changes to intertidal shorelines in urbanized estuaries: novel ways of improving altered habitat to maintain biodiversity
M. G. Chapman
Change in Aquatic Ecosystems: Natural and Human Influences, Marine Biological Association UK, University of Plymouth, Scottish Association for Marine Science, Freswater Biological Association UK, Plymouth, UK
4-6 July 2007
Until relatively recently, the effects of urbanization of marine habitats has focussed on contamination of water and sediments from disposal, spills and runoff. The loss, alteration and fragmentation of habitats by urban development, long the concern of terrestrial ecologists, have largely been ignored, except for those intertidal habitats dominated by large plants, such as wetlands, mangroves and saltmarsh. Intertidal habitats are limited in extent because they occupy that narrow fringe between the land and the sea subjected to tidal change. They are linear habitats, with strong upshore environmental gradients. Species in intertidal habitats occupy particular habitats, which is set by abiotic conditions and/or biotic interactions. Loss of or changes to intertidal habitats over large scales are therefore likely to affect many taxa, which do not have other habitats into which they can retreat.
Urban estuaries are greatly altered by development and with increasing urbanization; on the coast in particular, this is likely to increase. Of all marine habitats, the intertidal areas have been most affected, with replacement of many natural shores by built structures, including seawalls, groynes, marinas, etc. Although these structures differ markedly from natural shores, cursory examination suggests that they provide useful habitat for intertidal organisms, many of which reach large cover or densities on these structures. Detailed sampling shows that, in Sydney Harbour at least, intertidal seawalls do not provide suitable habitat for many taxa, which either do not live on artificial structures, live at abnormal densities or do not grow large, thus affecting reproductive output.
Comparison of the physical structure of built seawalls compared to rocky shores indicates some major features of habitat that are generally lacking on seawalls. Imaginative engineering may, however, be able to supply surrogates for these habitats. Some of the engineering changes to seawalls that are being trialled in Sydney Harbour will be described, with preliminary data on their effects on intertidal diversity.
Crab-tiling: An ecologically benign and sustainable fishery with an image problem
R.A. Coleman
Research Seminar Series, NSW DPI Fisheries Research Centre of Excellence, Cronulla
2007
Complex interactions in a rapidly changing world
Hawkins, S.J., Moore, P.M., Mieskowska, N., Leaper, R., Burrows, M., Poloczanska, E., Johnson, M.P., Jenkins, S.R., Pannacuilli, F., Coleman, R.A., Kendal, M., Thompson, R.C., Genner, M. & Southward, A.J.
42nd European Marine Biology Symposium, Kiel, Germany, 27-31st August 2007
Collaborative research projects to develop and assess methods for improving seawalls as intertidal habitat
D.J. Blockley and M.G. Chapman
16th NSW Coastal Conference, Yamba, NSW
7-9th November 2007
Urbanisation of coastal areas has led to the replacement of many natural intertidal habitats with artificial structures, in particular seawalls. Increasing coastal populations resulting in further urbanisation, coupled with rising sea-levels and increases in frequency and intensity of storms due to climate change will mean that seawalls will probably become more common. If intertidal animals and plants are to be sustained and protected, the impacts of seawalls need to be established and methods of improving the quality of seawalls as habitat needs rigorous experimental research. Despite the ubiquitous nature of seawalls worldwide and recent research showing that they are very different habitats from natural rocky shores, insufficient research has been done to evaluate different ways to build seawalls to make them better habitats. The necessary research that will give answers to mangers about how seawalls should be constructed requires collaborations between those building the seawalls (e.g. local councils, engineers, etc.) and those with scientific expertise in experimental ecology. New walls are being built and large stretches of existing seawalls are in need of maintenance or restoration. These maintenance and building programmes have formed the basis of collaborative research to test experimentally various methods of enhancing seawalls. By working in consultation with managers and engineers, methods have been developed to incorporate features into seawalls that are aesthetic, structurally sound and support a greater diversity of marine organisms. Results of some of these innovative studies will be discussed, with emphasis on the importance of partnerships between researchers and managers to address the environmental problems of coastal urbanisation.
Climatic change and dire consequences for intertidal assemblages: the interactions of climatic and ecological issues
A. J. Underwood
Change in Aquatic Ecosystems: Natural and Human Influences, Marine Biological Association UK, University of Plymouth, Scottish Association for Marine Science, Freswater Biological Association UK, Plymouth, UK
4-6 July 2007
The relatively rapid changes due to climatic warming are going to affect coastal habitats in major, mostly deleterious ways. The primary physical processes will be elevated sea-level, increased air temperatures (with major influences during low tide), increased variation in intensity and frequency of rainfall (or, in Australia, drought) and increased likelihood of storms on the coasts. Research into these has begun, but is mostly about predicting shifts in distributions due to increasing temperature. Research around Sydney, in contrast, has begun to focus on the effects of changes in physical environments due to climatic change and how these directly and indirectly affect ecological processes. Effects of severe storms on different organisms, the role of shelter from air-time, low-tidal temperatures, the effects of rising sea-level will be illustrated. The dramatic consequences for composition of assemblages due to deleterious effects of increased temperature on the animals’ food resources will be demonstrated. Predictions about climatic change in the absence of predictability about ecological interactions will be inaccurate and probably misleading.
(Spanish) Patrones de distribución de hidrozoos sobre Ecklonia radiata, estudios experimentales acerca de los factores responsables
Carolina J. Zagal
XII Congreso Latinoamericano de Ciencias del Mar. COLACMAR, ALICMAR Florianopolis, Brasil
April 19th 2007
Los estudios experimentales son fundamentales para entender y explicar los patrones de distribución y abundancia de organismos y los procesos ecológicos que los afectan. Los hidrozoos presentan dos patrones claros de distribución sobre las láminas del alga Ecklonia radiata. El porcentaje de cobertura de hidrozoos en (1) zonas basales, del medio y distales, son mayores en la periferia que en el centro del alga y en (2) la periferia y el centro del alga son mayores en el medio que en zonas distales y mayores en zonas distales que en las basales. En este trabajo se investigan experimentalmente dos modelos que podr'an explicar las diferencias encontradas. El primer modelo es que los patrones de distribución se explican por la estructura de E. radiata, es decir, las partes más heterogéneas y/o más complejas del alga tendrán más hidroides. El segundo es que existe una mayor perdida de hidrozoos en partes distales del alga que partes del medio. Se concluye que (1) los hidrozoos son más abundantes en partes del medio y la periferia del alga porque estas áreas son más complejas, (2) existe una mayor pérdida de hidrozoos de partes distales que de partes del medio del alga.
(Spanish) Efectos del sustrato sobre la distribución de hidrozoos. Estudios experimentales.
Carolina J. Zagal
Faculty of Science Seminar Series, Universidad Austral de Chile, Valdivia, Chile
April 2nd 2007
Los estudios experimentales son fundamentales para entender y explicar los patrones de distribución y abundancia de organismos y los procesos ecológicos que los afectan. Los hidrozoos presentan dos patrones claros de distribución sobre las láminas del alga Ecklonia radiata. El porcentaje de cobertura de hidrozoos en (1) zonas basales, del medio y distales, son mayores en la periferia que en el centro del alga y en (2) la periferia y el centro del alga son mayores en el medio que en zonas distales y mayores en zonas distales que en las basales. En este trabajo se investiga experimentalmente el modelo que los patrones de distribución se explican por la estructura de E. radiata, es decir, las partes más heterogéneas y/o más complejas del alga tendrán más hidroides.
Para probar este modelo, se utilizaron plantas artificiales (PAs) con dos niveles de heterogeneidad (suaves, Su o rugosas, Ru) y complejidad (simples, Si o frondosas, Fr). Se predijo que la cobertura de hidroides es mayor en la periferia y el medio del alga porque estas zonas (1) tienen rugosidades; (2) son frondosas; (3) tienen rugosidades y son frondosas; (4) tienen rugosidades o son frondosas. A partir de estos modelos espec'ficos, se pusieron a prueba las siguientes hipótesis: La cobertura de hidrozoos será mayor en PAs: (H1) rugosas (RuSi y RuFr) que suaves (SuSi y SuFr); (H2) frondosas (SuFr y RuFr) que simples (SuSi y RuSi); (H3) rugosas y frondosas (RuFr) que el resto (SuSi, RuSi, SuFr); (H4) rugosas o frondosas (SuFr, RuSi, RuFr) que suaves y simples (SuSi).
La cobertura de hidrozoos fue significativamente mayor en los tratamientos frondosos que en los simples y en la periferia que el centro de todos los tratamientos. Esto apoya el segundo modelo (la frondosidad o complejidad del alga aumenta la cobertura de hidrozoos).
Se concluye que existe una mayor cobertura de hidrozoos en las zonas del medio del alga y láminas periferales porque estas áreas son mas complejas (frondosas). Posiblemente también sean afectadas por la rugosidad en estas zonas, pero los niveles de heterogeneidad utilizados en este estudio, por si solos, no lo explican. Se destaca la importancia de utilizar unidades artificiales y estudios experimentales para poner a prueba modelos e hipótesis acerca de los procesos ecológicos que afectan a los organismos.