Community Ecology

Amphibian community richness in cropland and grassland playas in the Southern High Plains, USA

by Jo-Szu (Ross) Tsai

Venne, L. S., J.-S. Tsai, S. B. Cox, L. M. Smith, and S. T. McMurry. 2012 (In press). Wetlands. DOI 10.1007/s13157-012-0305-9

Land use mediated habitat changes are associated with global amphibian declines. Intensive farming occurs in the... more Land use mediated habitat changes are associated with global amphibian declines. Intensive farming occurs in the Southern High Plains, USA, causing habitat loss through cultivation and subsequent sedimentation of playa wetlands. We determined the effects of sedimentation and other factors (e.g., hydroperiod, vegetative cover, wetland volume loss due to sediment, and playa density) hypothesized to have an influence on amphibian species richness.We sampled amphibian species richness in 40 playas with cropland watersheds and 40 playas with native grassland watersheds. Hydroperiod was the primary factor influencing amphibian species richness; playas with longer hydroperiods had higher cumulative amphibian species richness than playas with shorter hydroperiods. Percent vegetative cover was also positively related to species richness. Sedimentation of playas in the Southern High Plains reduces hydroperiod length and the number of playas available to breeding amphibians, two factors influencing richness. Shortened hydroperiods negatively affect reproductive success of amphibian species with long larval periods [e.g., barred tiger salamander (Ambystoma tigrinum mavortium), American bullfrog (Rana catesbeiana)], limiting amphibian species richness. Efforts to conserve amphibian species richness in playas should focus on reducing sediment and ensuring availability of sufficient vegetative cover.

Species composition of Modellidae and Cerambycidae (Coleoptera) in a coppice woodland

by Kenta TAKADA

Leksono, A. S., Takada, K., Nakagoshi & Nakamura, K. (2006) Species composition of Modellidae and Cerambycidae (Coleoptera) in a coppice woodland. - Journal of Forest Research 11: 61-64.

Vertical and seasonal variation in the abundance and the species richness of Attelabidae and Cantharidae (Coleoptera) in a suburban mixed forest

by Kenta TAKADA

Leksono, A. S., Nakagoshi, N., Takada, K. & Nakamura, K. (2005) Vertical and seasonal variation in the abundance and the species richness of Attelabidae and Cantharidae (Coleoptera) in a suburban mixed forest. - Entomological Science 8: 235-243.

Across ecosystem comparisons of size structure: methods, approaches and prospects

by Dan Perkins

Understanding what structures ecological communities and how this may vary between different types of ecosystems is a... more Understanding what structures ecological communities and how this may vary between different types of ecosystems is a fundamental question in ecology. We develop a general framework for quantifying size-structure within and among different ecosystem types (e.g. terrestrial, freshwater or marine), via the use of a suite of bivariate relationships between organismal size and properties of individuals, populations, assemblages, pair-wise interactions, and network topology. Each of these relationships can be considered a dimension of size-structure, along which real communities lie on a continuous scale. For example, the strength, slope, or elevation of the body mass-versus-abundance or predator size-versus-prey size relationships may vary systematically among ecosystem types. We draw on examples from the literature and suggest new ways to use allometries for comparing among ecosystem types, which we illustrate by applying them to published data. Finally, we discuss how dimensions of size-structure are interconnected and how we could approach this complex hierarchy systematically. We conclude: (1) there are multiple dimensions of size-structure; (2) communities may be size-structured in some of these dimensions, but not necessarily in others; (3) across-system comparisons via rigorous quantitative statistical methods are possible, and (4) insufficient data are currently available to illuminate thoroughly the full extent and nature of differences in size-structure among ecosystem types.

Testing effects of consumer richness, evenness and body size on ecosystem functioning

by Dan Perkins

1. Numerous studies have revealed (usually positive) relationships between biodiversity and ecosystem
functioning... more 1. Numerous studies have revealed (usually positive) relationships between biodiversity and ecosystem
functioning (B-EF), but the underpinning drivers are rarely addressed explicitly, hindering
the development of a more predictive understanding.
2. We developed a suite of statistical models (where we combined existing models with novel ones)
to test for richness and evenness effects on detrital processing in freshwater microcosms. Instead of
using consumer species as biodiversity units, we used two size classes within three species (six
types). This allowed us to test for diversity effects and also to focus on the role of body size and biomass.
3. Our statistical models tested for (i) whether performance in polyculture was more than the sum
of its parts (non-additive effects), (ii) the effects of specific type combinations (assemblage identity
effects) and (iii) whether types behaved differently when their absolute or relative abundances were
altered (e.g. because type abundance in polyculture was lower compared with monoculture). The
latter point meant we did not need additional density treatments.
4. Process rates were independent of richness and evenness and all types performed in an additive
fashion. The performance of a type was mainly driven by the consumers’ metabolic requirements
(connected to body size). On an assemblage level, biomass explained a large proportion of detrital
processing rates.
5. We conclude that B-EF studies would benefit from widening their statistical approaches. Further,
they need to consider biomass of species assemblages and whether biomass is comprised of
small or large individuals, because even if all species are present in the same biomass, small species
(or individuals) will performbetter.

Global change and food webs in running waters

by Dan Perkins

Riverine habitats are vulnerable to a host
of environmental stressors, many of which are
increasing in... more Riverine habitats are vulnerable to a host
of environmental stressors, many of which are
increasing in frequency and intensity across the
globe. Climate change is arguably the greatest threat
on the horizon, with serious implications for freshwater
food webs via alterations in thermal regimes,
resource quality and availability, and hydrology. This
will induce radical restructuring of many food webs,
by altering the identity of nodes, the strength and
patterning of interactions and consequently the
dynamics and architecture of the trophic network as
a whole. Although such effects are likely to be
apparent globally, they are predicted to be especially
rapid and dramatic in high altitude and latitude
ecosystems, which represent ‘sentinel systems’. The
complex and subtle connections between members of
a food web and potential synergistic interactions with
other environmental stressors can lead to seemingly
counterintuitive responses to perturbations that cannot
be predicted from the traditional focus of
studying individual species in isolation. In this
review, we highlight the need for developing new
network-based approaches to understand and predict
the consequences of global change in running waters.

Climate change and freshwater ecosystems: impacts across multiple levels of organization

by Dan Perkins

Fresh waters are particularly vulnerable to climate change because (i) these fragmented habitats contain many species... more Fresh waters are particularly vulnerable to climate change because (i) these fragmented habitats contain many species with limited abilities to disperse as their environment changes, (ii) water temperature and availability are climate-dependent, and (iii) many systems are already exposed to a plethora of anthropogenic stressors that could amplify the effects of climate change. Most studies of potential climate change effects in aquatic systems have focused on individuals or species populations, rather than the higher levels of organisation (i.e. communities, food webs, ecosystems). We propose that an understanding of the connections between these different levels, which are all ultimately based on individuals, can be used to develop a more coherent theoretical framework, via an integration of metabolic scaling, foraging theory, and ecological stoichiometry, to predict the ecological consequences of climate change. For instance, individual basal metabolic rate scales with body size, which is also a strong driver of food web structure and dynamics, and temperature, which determines many ecosystem process rates and key aspects of foraging behaviour. In addition increasing atmospheric CO2 is predicted to alter molar the CNP ratios of detrital inputs, which could lead to profound shifts in the stoichiometry of elemental fluxes between consumers and resources at the base of the food web. The different components of climate change (temperature, hydrology and atmospheric composition) not only affect multiple levels of biological organisation, but they also interact with the numerous other stressors that fresh waters are exposed to, and future research needs to address these potentially important synergies.

The Temperature Dependence of the Carbon Cycle in Aquatic Ecosystems

by Gabriel Yvon-Durocher

The carbon cycle modulates climate change via the regulation of atmospheric CO2, and represents one of the most... more The carbon cycle modulates climate change via the regulation of atmospheric CO2, and represents one of the most important ecosystem services of value to humans. However, considerable uncertainties remain concerning potential feedbacks between the biota and the climate. We developed theoretical models
derived from the metabolic theory of ecology (MTE), and tested them in an ecosystem-level manipulative experiment in freshwater mesocosms. The yearlong experiment simulated a warming scenario (A1B; [IPCC, 2007]) expected by the end of the century. The key components of the carbon cycle – that is gross primary production (GPP), ecosystem respiration (ER) and CH4 efflux (ME) – measured in our experiment were all strongly related to temperature. Their temperature dependence was typically constrained by the average activation energy of their particular metabolic pathway, and as predicted by our models, this increased progressively for GPP, ER and ME. Warming of 4°C decreased the sequestration of CO2 by 13%, increased the fraction of primary production effluxing as methane by 20% and the fraction of ER as methane by 9%, in line with the offset in their respective activation energies. Because methane has 21 times the greenhouse gas radiative potential of CO2, these results suggest aquatic ecosystems could drive a previously unknown positive feedback between warming and the carbon cycle.

We then used a series of global data compilations of measurements of rates of primary production and respiration to better understand the temperature dependence of the carbon cycle in other aquatic ecosystems and to compare them with data from terrestrial systems. Our experimental results were mirrored by our global data compilations, with the effective activation energy for marine and freshwater primary production identical to GPP measured in our experiment. Similarly, the temperature dependences of respiration in estuaries, lakes and the ocean were indistinguishable from that of ER in our experiment. Finally, our study suggests that the temperature dependence of primary production and respiration in aquatic ecosystems might differ from those in terrestrial ecosystems, and this could be crucial in predicting the future response of the carbon cycle in these different systems to global warming.

Warming alters the size spectrum and shifts the distribution of biomass in freshwater ecosystems

by Gabriel Yvon-Durocher

Organism size is one of the key determinants of community structure, and its relationship with abundance can describe... more Organism size is one of the key determinants of community structure, and its relationship with abundance can describe how biomass is partitioned among the biota within an ecosystem. An outdoor freshwater mesocosm experiment was used to determine how warming of 4°C would affect the size, biomass and taxonomic structure of planktonic communities. Warming increased the steepness of the community size spectrum by increasing the prevalence of small organisms, primarily within the phytoplankton assemblage and it also reduced the mean and maximum size of phytoplankton by approximately one order of magnitude. The observed shifts in phytoplankton size structure were reflected in changes in phytoplankton community composition, though zooplankton taxonomic composition was unaffected by warming. Furthermore, warming reduced community biomass and total phytoplankton biomass, although zooplankton biomass was unaffected. This resulted in an increase in the zooplankton to phytoplankton biomass ratio in the warmed mesocosms, which could be explained by faster turnover within the phytoplankton assemblages. Overall, warming shifted the distribution of phytoplankton size towards smaller individuals with rapid turnover and low standing biomass, resulting in a reorganization of the biomass structure of the food webs. These results indicate future environmental warming may have profound effects on the structure and functioning of aquatic communities and ecosystems.

Warming alters community size structure and ecosystem functioning

by Gabriel Yvon-Durocher

Global warming can affect all levels of biological complexity, though we currently understand least about its... more Global warming can affect all levels of biological complexity, though we currently understand least about its potential impact on communities and ecosystems. At the ecosystem level, warming has the capacity to alter the structure of communities and the rates of key ecosystem processes they mediate. Here we assessed the effects of a 4C rise in temperature on the size structure and taxonomic composition of benthic communities in aquatic mesocosms, and the rates of detrital decomposition they mediated. Warming had no effect on biodiversity, but altered community size structure in two ways. In spring, warmer systems exhibited steeper size spectra driven by declines in total community biomass and the proportion of large organisms. By contrast, in autumn, warmer systems had shallower size spectra driven by elevated total community biomass and a greater proportion of large organisms. Community-level shifts were mirrored by changes in decomposition rates. Temperature-corrected microbial and macrofaunal decomposition rates reflected the shifts in community structure and were strongly correlated with biomass across mesocosms. Our study demonstrates that the 4C rise in temperature expected by the end of the century has the potential to alter the structure and functioning of aquatic ecosystems profoundly, as well as the intimate linkages between these levels of ecological organization.

Across ecosystem comparisons of size structure: methods, approaches and prospects

by Gabriel Yvon-Durocher

Understanding how ecological communities are structured and how this may vary between different types of ecosystems is... more Understanding how ecological communities are structured and how this may vary between different types of ecosystems is a fundamental question in ecology. We develop a general framework for quantifying size-structure within and among different ecosystem types (e.g. terrestrial, freshwater or marine), via the use of a suite of bivariate relationships between organismal size and properties of individuals, populations, assemblages, pair-wise interactions, and network topology. Each of these relationships can be considered a dimension of size-structure, along which real communities lie on a continuous scale. For example, the strength, slope, or elevation of the body mass-versus-abundance or predator size-versus-prey size relationships may vary systematically among ecosystem types. We draw on examples from the literature and suggest new ways to use allometries for comparing among ecosystem types, which we illustrate by applying them to published data. Finally, we discuss how dimensions of size-structure are interconnected and how we could approach this complex hierarchy systematically. We conclude: (1) there are multiple dimensions of size-structure; (2) communities may be size-structured in some of these dimensions, but not necessarily in others; (3) across-system comparisons via rigorous quantitative statistical methods are possible, and (4) insufficient data are currently available to illuminate thoroughly the full extent and nature of differences in size-structure among ecosystem types.

Bird community in a forest patch isolated by the urban matrix at the Sinos River basin, Rio Grande do Sul state, Brazil, with comments on the possible local …

by Ismael Franz

Bats with Aspergillus from Kubah National Park. 2008.

by M.T. Abdullah, PhD

A preliminary survey of chiropterans (bats) with potential zoonotic fungi was conducted as part of the Sowell-UNIMAS... more A preliminary survey of chiropterans (bats) with potential zoonotic fungi was conducted as part of the Sowell-UNIMAS Expedition 2006. This survey was conducted at Kubah National Park, Matang, Sarawak from 14th to 16th August 2006. The main aim of this survey was to document variety of fungal isolates from bats external (ears) and internal (saliva and anal) swabs. All of the fungi species were subjected to both macroscopic and microscopic observations to characterize their morphology. Out of 23 species of bats observed, 13 (56.5%) species were found to contain 17 fungi isolates of the genus Aspergillus from five subgenera, five sections and six species. The fungi isolates were Aspergillus restrictus, A. sydowii, A. fumigatus, A. niger, A. clavatus and A. japonicus. The highest numbers of isolates recorded was for A. restrictus with six isolates followed by A. fumigatus and A. sydowii with two isolates respectively. Where as, A. niger, A. clavatus and A. japonicus each recorded with one isolate only. Aspergillus fumigatus was the first record isolated from bats the samples (n = 64) from Sarawak. It was reported that this isolate is a pathogenic and thermophilic (able to grow up to 65°C) isolate which was found to be on a lesion near ear opening of Hipposideros cervinus. Further work should be done to discover potential mycoflora in wildlife mammals.

Small mammals of Gunung Silam, Sabah, Malaysian Borneo. 2009

by M.T. Abdullah, PhD

Cave Bats of Sarawak Malaysian Borneo. 2011

by M.T. Abdullah, PhD

New records for bats observed during this study New records for bats observed during this study

Biogeography of fruit bats in Southeast Asia. Les S. Hall, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni and M.T. Abdullah.

by M.T. Abdullah, PhD

Should read Abdullah (2003).

We studied on the biogeography and diversity of fruit bats in Southeast Asia, from Borneo to Asian Mainland.The... more We studied on the biogeography and diversity of fruit bats in Southeast Asia, from Borneo to Asian Mainland.The patterns of distribution of distribution, diversity and abundance are related to ecological and biogeographical factors and possible past Pleistocene events.

Les S. Hall, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni and M.T. Abdullah. 2004. Sarawak Museum Journal 81: 191-284.

Mammalian Diversity, Evolution and Potential Reservoir of Diseases. 2011

by M.T. Abdullah, PhD

SOCIAL AND ECOLOGICAL DIMENSION OF INFECTIOUS DISEASES BANGKOK, 6-7 OCTOBER 2011.

Key words: Biodiversity, Diseases, Zoonosis, Climate Change, Evolution Key words: Biodiversity, Diseases, Zoonosis, Climate Change, Evolution

The Use of Green Space for Urban Communities

by Bram Vanhoutte

In: Green Days. A multidisciplinary project on art and nature. 2012

To grasp the utility of green space, it’s important to understand the thinking around urban communities, which is... more To grasp the utility of green space, it’s important to understand the thinking around urban communities, which is sketched out concisely in this contribution. The second part of this text focuses on the effects of green space on community, and the mechanisms involved. We close with a discussion on green space in the city, and its role.

Niche segregation in two closely related species of stickleback along a physiological axis: Explaining multidecadal changes in fish distribution from iron-induced respiratory impairment.

by Wilco Verberk

Aquatic Ecology in press, doi: 10.1007/s10452-012-9395-y

Acute exposure to iron can be lethal to fish, but long-term sublethal impacts of iron require further study. Here we... more Acute exposure to iron can be lethal to fish, but long-term sublethal impacts of iron require further study. Here we investigated whether the spatial and temporal distribution (1967–2004) of two closely related species of stickleback matched the spatial distribution of iron concentrations in the groundwater.
We used the ‘Northern Peel region’, a historically iron-rich peat landscape in The Netherlands as a case study. This allowed us to test the hypothesis that niche segregation in two closely related species of stickleback occurred along a
physiological axis. Patterns in stickleback occurrence were strongly associated with spatial patterns in iron concentrations before 1979: iron-rich grid cells were avoided by three-spined stickleback (Gasterosteus aculeatus , Linnaeus 1758) and preferred by nine-spined stickleback (Pungitius pungitius , [Linnaeus, 1758]).
After 1979, the separation between both sticklebacks became weaker, corresponding to a decreased influence of local groundwater on stream water quality. The way both species changed their distribution in the field provides a strong indication that they differ in their susceptibility to iron-rich conditions. These observed differences correspond with differences in their respiration physiology, tolerance of poor oxygen conditions
and overall life-history strategy documented in the literature.
Our results exemplify how species can partition niche along a non-structural niche axis, such as sublethal iron-rich conditions. Other fish species may similarly segregate along concentration gradients in iron, while sublethal concentrations of other metals such as copper
may similarly impact fish via respiratory impairment and reduced aerobic scope.

Patterns of elevational beta diversity in micro- and macroorganisms

by jianjun wang

Wang, Jianjun. Soininen, Janne. Zhang, Yong. Wang, Beixin. Yang, Xiangdong. Shen, Ji. Patterns of elevational beta diversity in micro- and macroorganisms, Global Ecology and Biogeography, In press

Keywords
Bacteria, beta diversity, Beta-sim, biogeography, China, diatoms, elevational gradient, human activities, macroecology, macroinvertebrates, species turnover, streams

Aim  While ecologists have long been interested in diversity in mountain regions, elevational patterns in beta... more Aim  While ecologists have long been interested in diversity in mountain regions, elevational patterns in beta diversity are still rarely studied across different life forms ranging from micro- to macroorganisms. Also, it is not known whether the patterns in turnover among organism groups are affected by the degree to which the environment is modified by human activities.

Location  Laojun Mountain, Yunnan Province, China.

Methods  The beta diversity patterns of benthic microorganisms (i.e. diatoms and bacteria) and macroorganisms (i.e. macroinvertebrates) in a stony stream were simultaneously investigated between elevations of 1820 and 4050 m. Data were analysed by using a distance-based approach and variation partitioning based on canonical redundancy analysis.

Results  Analyses of community dissimilarities between adjacent sampling sites showed comparable small-scale beta diversity along the elevational gradient for the organism groups. However, bacteria clearly showed the lowest elevational turnover when analyses were conducted simultaneously for all pairwise sites. Variation partitioning indicated that species turnover was mostly related to environmental heterogeneity and spatial gradients including horizontal distance and elevation, while purely human impacts were shown to be less important.

Main conclusions  The elevational beta diversity at large scales was lower for bacteria than for eukaryotic microorganisms or macroorganisms, perhaps indicative of high dispersal ability and good adaptability of bacteria to harsh environmental conditions. However, the small-scale beta diversity did not differ among the groups. Elevation was the major driver for the turnover of eukaryotic organisms, while the turnover of bacteria was correlated more with environmental variation.