Spatial and temporal variation in the infracommunity structure of helminths of Apodemus sylvaticus(Rodentia: Muridae)

SummaryMean species richness and diversity of the helminth infracommunity of Apodemus sylvaticus in woodland areas of Co. Down, Northern Ireland, varied in time and space. Variation in infracommunity structure among individual hosts, however, always accounted for more than 60% of the variation in the data from different places or different times. Helminth species richness increased with increasing population density, the percentage of the host population 16 weeks old or older, and the proportion of the host population with animal material in their stomachs, at two sites monitored over 33 months. The basis for spatial variation in infracommunity structure is less certain but host dynamics and differences in diet are likely to play some role. It is concluded that analysis at the infracommunity level focuses closely on the potential for species interactions and overlap in resource utilization. Infracommunity structure, at least in the case of A. sylvaticus, varies markedly in time and space and between individual hosts. Such variation should not be ignored in comparative studies.

Download Full-text

Fish population size, and not density, as the determining factor of parasite infection: a case study

Parasitology ◽

10.1017/s0031182003004566 ◽

2004 ◽

Vol 128 (3) ◽

pp. 305-313 ◽

Cited By ~ 58

Author(s):

A. M. BAGGE ◽

R. POULIN ◽

E. T. VALTONEN

Keyword(s):

Species Richness ◽

Population Density ◽

Population Size ◽

Fish Population ◽

Host Population ◽

Fish Length ◽

Total Fish ◽

Infection Parameters ◽

The Mean

The diversity and abundance of parasites vary widely among populations of the same host species. These infection parameters are, to some extent, determined by characteristics of the host population or of its habitat. Recent studies have supported predictions derived from epidemiological models regarding the influence of host population density: parasite abundance and parasite species richness are expected to increase with increasing host population density, at least for directly transmitted parasites. Here, we test this prediction using a natural system in which populations of the crucian carp, Carassius carassius (L.), occur alone, with no other fish species, in a series of 9 isolated ponds in Finland. The ectoparasite communities in these fish populations consist of only 4 species of monogeneans (Dactylogyrus formosus, D. wegeneri, D. intermedius and Gyrodactylus carassii); the total and relative abundance of these 4 species varies among ponds, with one or two of the species missing from certain ponds. Across ponds, only one factor, total fish population size, explained a significant portion of the variance in both the mean number of monogenean species per fish and the mean total abundance of monogenean individual per fish. In contrast, fish population density did not influence either monogenean abundance or species richness, and neither did any of the other variables investigated (mean fish length per pond, number of fish examined per pond, distance to the nearest lake, and several water quality measures). In our system, proximity among fish individuals (i.e. host population density) may not be relevant to the proliferation of monogeneans; instead, the overall availability of host individuals in the host population appeared to be the main constraint limiting parasite population growth.

Download Full-text

Energetic and ecological constraints on population density of reef fishes

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2015.2186 ◽

2016 ◽

Vol 283 (1823) ◽

pp. 20152186 ◽

Cited By ~ 19

Author(s):

D. R. Barneche ◽

M. Kulbicki ◽

S. R. Floeter ◽

A. M. Friedlander ◽

A. P. Allen

Keyword(s):

Species Richness ◽

Body Size ◽

Population Density ◽

Species Interactions ◽

Spatial Scales ◽

Small Body ◽

Reef Fishes ◽

Abundant Species ◽

Global Scale ◽

Ecological Constraints

Population ecology has classically focused on pairwise species interactions, hindering the description of general patterns and processes of population abundance at large spatial scales. Here we use the metabolic theory of ecology as a framework to formulate and test a model that yields predictions linking population density to the physiological constraints of body size and temperature on individual metabolism, and the ecological constraints of trophic structure and species richness on energy partitioning among species. Our model was tested by applying Bayesian quantile regression to a comprehensive reef-fish community database, from which we extracted density data for 5609 populations spread across 49 sites around the world. Our results indicate that population density declines markedly with increases in community species richness and that, after accounting for richness, energetic constraints are manifested most strongly for the most abundant species, which generally are of small body size and occupy lower trophic groups. Overall, our findings suggest that, at the global scale, factors associated with community species richness are the major drivers of variation in population density. Given that populations of species-rich tropical systems exhibit markedly lower maximum densities, they may be particularly susceptible to stochastic extinction.

Download Full-text

Host population density and body mass as determinants of species richness in parasite communities: comparative analyses of directly transmitted nematodes of mammals

Ecography ◽

10.1034/j.1600-0587.2002.250110.x ◽

2002 ◽

Vol 25 (1) ◽

pp. 88-94 ◽

Cited By ~ 129

Author(s):

Per Arneberg

Keyword(s):

Species Richness ◽

Population Density ◽

Body Mass ◽

Host Population ◽

Comparative Analyses ◽

Parasite Communities

Download Full-text

Mountain definitions and their consequences

Alpine Botany ◽

10.1007/s00035-021-00265-8 ◽

2021 ◽

Author(s):

Christian Körner ◽

Davnah Urbach ◽

Jens Paulsen

Keyword(s):

Species Richness ◽

Population Density ◽

Climatic Change ◽

Plant Species ◽

Human Population ◽

Short Communication ◽

Plant Species Richness ◽

Mountainous Terrain ◽

Human Population Density

AbstractMountains are rugged structures in the landscape that are difficult to delineate. Given that they host an overproportional fraction of biodiversity of high ecological and conservational value, conventions on what is mountainous and what not are in need. This short communication aims at explaining the differences among various popular mountain definitions. Defining mountainous terrain is key for global assessments of plant species richness in mountains and their likely responses to climatic change, as well as for assessing the human population density in and around mountainous terrain.

Download Full-text

Bird and mammal conservation in Gaoligongshan Region and Jingdong County, Yunnan, China: patterns of species richness and nature reserves

Oryx ◽

10.1046/j.1365-3008.2000.00131.x ◽

2000 ◽

Vol 34 (4) ◽

pp. 275-286 ◽

Cited By ~ 6

Author(s):

Daoying Lan ◽

Robin Dunbar

Keyword(s):

Species Richness ◽

Population Density ◽

Human Population ◽

Yunnan Province ◽

Nature Reserve ◽

Present Situation ◽

Primary Forest ◽

Mammal Conservation ◽

Latitudinal Patterns ◽

Conservation Of Biodiversity

AbstractElevational and latitudinal patterns of species richness for birds and mammals were compared with human population density in relation to nature reserve designation in two areas of Yunnan Province, China. Results suggest that species richness is not the same for the two areas. In Gaoligongshan Region, species richness is inversely correlated with elevation and altitude, while reserve designation is positively correlated with elevation and latitude. In Jingdong County, reserve designations are positively correlated with elevation, but species richness shows no clear trends. In general, the present situation is strongly influenced by human activities. It appears that reserve designation is mismatched with species richness in Gaoligongshan Region, while there is a better fit between the two in Jingdong County. In both areas, however, it appeared that reserves were located primarily in order to reduce conflict with humans rather than to maximize conservation of biodiversity, probably because humans were responsible for forest—especially primary forest—destruction and degradation in the low-lying areas.

Download Full-text

Parasite infection and host dynamics in a naturally fluctuating rodent population

Canadian Journal of Zoology ◽

10.1139/z2012-083 ◽

2012 ◽

Vol 90 (9) ◽

pp. 1149-1160 ◽

Cited By ~ 17

Author(s):

J.C. Winternitz ◽

M.J. Yabsley ◽

S.M. Altizer

Keyword(s):

Population Density ◽

Experimental Studies ◽

Host Density ◽

Positive Association ◽

Population Cycles ◽

Host Population ◽

Reproductive Status ◽

Vole Cycles ◽

Host Infection ◽

The Impact

Parasites can both influence and be affected by host population dynamics, and a growing number of case studies support a role for parasites in causing or amplifying host population cycles. In this study, we examined individual and population predictors of gastrointestinal parasitism on wild cyclic montane voles ( Microtus montanus (Peale, 1848)) to determine if evidence was consistent with theory implicating parasites in population cycles. We sampled three sites in central Colorado for the duration of a multiannual cycle and recorded the prevalence and intensity of directly transmitted Eimeria Schneider, 1875 and indirectly transmitted cestodes from a total of 267 voles. We found significant associations between host infection status, individual traits (sex, age, and reproductive status) and population variables (site, trapping period, and population density), including a positive association between host density and cestode prevalence, and a negative association between host density and Eimeria prevalence. Both cestode and Eimeria intensity correlated positively with host age, reproductive status, and population density, but neither parasite was associated with poorer host condition. Our findings suggest that parasites are common in this natural host, but determining their potential to influence montane vole cycles requires future experimental studies and long-term monitoring to determine the fitness consequences of infection and the impact of parasite removal on host dynamics.

Download Full-text