ArticlePublisher preview available

How are arthopod communities structured and why are they so diverse? Answers from Mediterranean mountains using hierarchical additive partitioning

Authors:
Dina Zografou at University of Ioannina
Dina Zografou
Robert J Wilson at The National Museum of Natural Sciences
Robert J Wilson
John M. Halley at University of Ioannina
John M. Halley
Elli Tzirkalli at Open University of Cyprus
Elli Tzirkalli
Show all 5 authorsHide
Read publisher preview
Download citation
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

Mountains are complex ecosystems supporting a great variety of taxa. Here, we explored the diversity patterns of arthropods in two mountains, pinpointing the spatial scale that accounts most for overall diversity variation, using an additive partitioning framework. Butterflies and Orthoptera were sampled in Rodopi (2012) and Grammos (2013) mountains. Diversity was partitioned into five hierarchical levels (mountain, elevational zone, habitat, transect and plot). We compared the estimated diversity values for each level to the respective permuted values expected by chance, for all species, as well as for species identified as “rare” or “common”. At broader spatial levels, the variation in total diversity was attributed to the beta diversity component: mountains accounted for 20.94 and 26.25% of butterfly and Orthoptera diversity, and elevational zones accounted for 28.94 and 35.87% respectively. At finer spatial scales, beta diversity was higher than expected by chance in terms of the Shannon index. The type of habitat was found to play a significant role only for rare orthopterans. Finally, common species were recognized for shaping overall species diversity. We highlight the importance of the spatial levels of elevation zone and then mountain position in conservation planning, due to the greater beta diversity recorded at this scale as compared to habitat or more finite scales. Monitoring programs might need to adapt different strategies with respect to the focal organisms, and consider patterns of common rather than rare species that found to drive the patterns of the entire community.
Figures - available from: Biodiversity and Conservation
This content is subject to copyright. Terms and conditions apply.
A preview of this full-text is provided by Springer Nature.
Learn more
Content available from Biodiversity and Conservation
This content is subject to copyright. Terms and conditions apply.
ORIGINAL PAPER
How are arthopod communities structured and why are
they so diverse? Answers from Mediterranean mountains
using hierarchical additive partitioning
Konstantina Zografou
1
•Robert J. Wilson
2
•
John M. Halley
1
•Elli Tzirkalli
1
•Vassiliki Kati
1
Received: 15 May 2016 / Revised: 2 December 2016 / Accepted: 24 January 2017 /
Published online: 31 January 2017
ÓSpringer Science+Business Media Dordrecht 2017
Abstract Mountains are complex ecosystems supporting a great variety of taxa. Here, we
explored the diversity patterns of arthropods in two mountains, pinpointing the spatial scale
that accounts most for overall diversity variation, using an additive partitioning framework.
Butterflies and Orthoptera were sampled in Rodopi (2012) and Grammos (2013) moun-
tains. Diversity was partitioned into five hierarchical levels (mountain, elevational zone,
habitat, transect and plot). We compared the estimated diversity values for each level to the
respective permuted values expected by chance, for all species, as well as for species
identified as ‘‘rare’’ or ‘‘common’’. At broader spatial levels, the variation in total diversity
was attributed to the beta diversity component: mountains accounted for 20.94 and 26.25%
of butterfly and Orthoptera diversity, and elevational zones accounted for 28.94 and
35.87% respectively. At finer spatial scales, beta diversity was higher than expected by
chance in terms of the Shannon index. The type of habitat was found to play a significant
role only for rare orthopterans. Finally, common species were recognized for shaping
overall species diversity. We highlight the importance of the spatial levels of elevation
zone and then mountain position in conservation planning, due to the greater beta diversity
recorded at this scale as compared to habitat or more finite scales. Monitoring programs
might need to adapt different strategies with respect to the focal organisms, and consider
patterns of common rather than rare species that found to drive the patterns of the entire
community.
Communicated by Jan C. Habel.
Electronic supplementary material The online version of this article (doi:10.1007/s10531-017-1303-2)
contains supplementary material, which is available to authorized users.
&Konstantina Zografou
ntinazografou@yahoo.co.uk
1
Department of Biological Applications and Technology, University of Ioannina, Ioannina, Greece
2
College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4PS, UK
123
Biodivers Conserv (2017) 26:1333–1351
DOI 10.1007/s10531-017-1303-2
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... This suggests that landscape attributes were more favourable for the specialist group than the forest type. Greater beta diversity was observed at the elevation zone scale compared to habitat or ner scales in this study, supported by (Zografou et al. 2017). Furthermore, habitat specialists species were predominantly concentrated at higher altitudes and generalists dropped during severe land use changes associated with aridity and specialists were negatively impacted by temperature. ...
... One 500 m transect was placedin each forest type (Open forest: OF, Riparian forest: RF, and Dense forest: DF) in each study site. The mean distance between transects in each site was 1.5 ± 0.25 km and the mean distance among study sites was 39 ± 8.64 km, so each transect represented an independent sample(Zografou et al. 2017). ...
... An additive partitioning framework expressed by species richness and Shannon-Wiener index (H') has been used in this study to test the null hypothesis that butter y diversity is uniform in all spatial scale(Zografou et al. 2017). The pooled data from all sample months were aggregated by three spatial scale, i.e., transects (144 units), forest types(12 units), and elevation-based study sites (landscape level, 4units) in order to access the species diversity. ...
The composition and phenology of butterflies is determined by their functional trait in Indian tropical dry forests
Preprint
Full-text available
  • Aug 2023
To understand the effects of local landscape factors on functional species composition and phenology of butterflies across multiple spatial scales, a study was carried out in a tropical dry forest of the northern highlands of the Eastern Ghats of India from November 2016 to October 2017. A total of 3343 individuals of butterflies were recorded, including 88 species of butterflies under 62 genera, 18 subfamilies, and 6 families in three different forest types (open, riparian, dense). Butterfly species richness showed no significant deviations, but diversity patterns varied across transects. Beta diversity indicated differences in common species populations, likely due to uneven resource distribution in study site forests. The contribution of β transect to gamma diversity was greater than that of β elevation, except for specialists. Specialists were favoured by landscape attributes over forest type. Butterfly abundance peaks in April for open and dense forests, and May for riparian forests. Results show variation in seasonal patterns across different forest types (F = 15.92, P < 0.001). Generalists and versatilists are more prevalent in April and February, while specialists are more abundant from October to November. Relative humidity, shrub density, and temperature were the major contributors (40.2%) for richness whereas relative humidity and shrub density contributed 26.3% for abundance. The relative humidity was predominant over temperature for species richness and is a major predictor for assemblages of generalist species. Resource utilization based on elevation plays an important role for habitat specialist species and highlights the importance of the spatial levels of elevation zones in conservation planning.
View
... The relative abundance is defined as the percentage of each species contributed to the total number of individuals of all species (Magurran 2004). In addition, an additive partitioning framework has been used in this study to test the null hypothesis that butterfly diversity is uniform in all spatial scales i.e., transects, forest types, and elevation-based study sites (Zografou et al. 2017). ...
... This suggests that landscape attributes were more favourable for the specialist group than the forest type. Greater β diversity was observed at the elevation zone scale compared to habitat or finer scales in this study, supported by the findings of Zografou et al. (2017). Similar results were also found from studies carried out in this region (Mahata et al. 2019a(Mahata et al. , 2023Mahata and Palita 2023), which reported that the species richness in the eastern high-elevation ranges (Koraput Plateau), is higher than that of the western low elevation zone (Jeypore Plateau). ...
The composition and phenology of butterflies are determined by their functional trait in Indian tropical dry forests
Article
Full-text available
  • Mar 2024
  • BIODIVERS CONSERV
To understand the effects of local landscape factors on functional species composition and phenology of butterflies across multiple spatial scales, a study was carried out in a tropical dry forest of the northern highlands of the Eastern Ghats of India from November 2016 to October 2017. A total of 3343 individuals of 88 species of butterflies were recorded, under 62 genera, 18 subfamilies, and six families in three different forest types (open, riparian, dense). Butterfly species richness showed no significant deviations, but diversity patterns varied across transects. Beta diversity indicated differences in common species populations, likely due to uneven resource distribution in study site forests. The contribution of β transect to gamma diversity was greater than that of β elevation, except for specialists. Specialists were favoured by landscape attributes over forest type. Butterfly abundance peaks in April for open and dense forests and May for riparian forests. Results show variation in seasonal patterns across different forest types (F = 15.92, P < 0.001). Generalists and versatilists are more prevalent in April and February, while specialists are more abundant from October to November. Relative humidity, shrub density, and temperature were the major contributors (40.2%) for richness, whereas relative humidity and shrub density contributed 26.3% for abundance. The relative humidity was predominant over temperature for species richness and is a major predictor for assemblages of generalist species. Elevation-dependent resource utilization is crucial for habitat specialists, underscoring the significance of spatial elevation zones in effective conservation planning strategies.
View
... The change in vegetation types along elevation gradients often affects the composition of species, leading to differences in fauna between low and high elevations (e.g., Aisen et al., 2017;González-Reyes et al., 2017;García-L opez et al., 2012;Liu et al., 2018;Werenkraut & Ruggiero, 2013). Each vegetation type may be part of a unique biogeographic unit or eco-region representing a macro-habitat for insects, which is why the composition of species assemblages on summits of different mountains can be more similar to each other than that with lower vegetation belts of the same mountain (e.g., Aisen et al., 2017;Liu et al., 2018;Werenkraut & Ruggiero, 2013;Zografou et al., 2017). Changes in vegetation structure are often associated with differences in plant biomass/ production and diversity of functional attributes (Sundqvist et al., 2013), which affect the local climatic conditions and the resources available for insects. ...
... The impact of the forest-steppe transition on pre-and post-eruption beetle composition This study showed that the taxonomic composition of mountain epigaeic beetle assemblages is strongly structured along elevation gradients. The vertical division of mountains into different macro-habitats characterised by different vegetation types was more important than the geographical distance between mountains in shaping the taxonomic composition of beetle assemblages, consistent with findings in other mountain regions (Aisen et al., 2017;Escobar et al., 2005;Liu et al., 2018;Zografou et al., 2017). This pattern reflects a species sorting process (sensu Leibold et al., 2004;Liu et al., 2018), wherein environmental variation plays a more pivotal role than dispersal limitation in shaping taxonomic composition (see also Aisen et al., 2017;Werenkraut & Ruggiero, 2013). ...
Ecological responses of epigaeic beetle composition to a volcanic eruption across temperate mountains featuring a forest‐steppe transition
Article
  • Nov 2023
Monitoring changes in species composition near active volcanoes is important to identify environmental factors that maintain biological diversity after major disturbances. We investigated the taxonomic composition of epigaeic beetles' assemblages in five mountains in north‐western Patagonia (Argentina) in the aftermath of the 2011 Puyehue Cordón‐Caulle Volcanic Complex eruption. The associations of beetle composition with the thermal environment, vegetation structure and soil characteristics were analysed using 10 m × 10 m plots with nine pitfall traps each, established 100 m apart in altitude on each mountain in 2005, 2006 (pre‐eruption) and 2012, 2015 and 2016 (post‐eruption). We found significant differences in beetle composition between forests and high‐Andean steppes before and after the eruption. The beetle composition of forests and high‐Andean steppes differed due to higher plant cover and lower pH and herb richness in forests. Six months after the eruption, the herbs almost disappeared and forests showed high ash accumulation and lower temperature than the high‐Andean steppes. In the medium term, plant cover, temperature and soil conditions—but not ash accumulation—remained as important correlates of beetle composition. Before the eruption, forest assemblages showed higher beetle diversity and Leiodidae indicator species, but Curculionidae predominated post‐eruption. Tenebrionidae and Carabidae were high Andean steppes indicators. Post‐eruption, the beetle composition in high‐Andean steppes did not change significantly except for an increase in Tenebrionidae indicator species. We concluded that the conservation of landscape diversity and environmental gradients maintaining the differentiation between ecoregions is essential to protect epigaeic beetle composition and for species survival after volcanic disturbances.
View
... Butterflies were counted from 0900 to 1300 h via a transect walk method, with a constant space of 60 min for each transect. A transect of 500 m was surveyed in each sampling site (2 × 2 km 2 grids), with an average intervening distance of 12 km between grids, so that each transect represented an independent sample [36]. We counted butterflies for a six-month period during the dry season from December 15 to June 5 in the year 2019, as counting could not be undertaken during the wet season due to the cloudy skies and heavy downpours. ...
... Butterflies were counted from 0900 to 1300 h via a transect walk method, with a constant space of 60 min for each transect. A transect of 500 m was surveyed in each sampling site (2 × 2 km 2 grids), with an average intervening distance of 12 km between grids, so that each transect represented an independent sample [36]. We counted butterflies for a sixmonth period during the dry season from December 15 to June 5 in the year 2019, as counting could not be undertaken during the wet season due to the cloudy skies and heavy downpours. ...
Microclimate and Vegetation Structure Significantly Affect Butterfly Assemblages in a Tropical Dry Forest
Article
Full-text available
  • Nov 2023
Understanding the factors that influence the diversity and distribution of butterfly species is crucial for prioritizing conservation. The Eastern Ghats of India is an ideal site for such a study, where butterfly diversity studies have yet to receive much attention. This study emphasized the butterfly assemblages of three prominent habitats in the region: open forests, riparian forests, and dense forests. We hypothesized that riparian forests would be the most preferred habitat for the butterflies, as they provide suitable microclimatic conditions for butterflies. The study collected samples for 35 grids of 2 × 2 km 2 for each habitat during the dry months (December-June). We considered the relative humidity, temperature, light intensity, elevation, and canopy cover to assess their influences on butterfly richness and abundance. We also considered the impact of disturbances on their distribution. We used structural equation modeling and canonical correspondence analysis to quantify the correlation and causation between the butterflies and their environment. The study recorded 1614 individual butterflies of 79 species from 57 genera and 6 families. During the study, we found that temperature was the most significant factor influencing butterfly richness. Relative humidity was also important and had a positive impact on butterfly richness. Riparian forests, where daytime temperatures are relatively low, were the most preferred microhabitat for butterflies. Open forests had greater species diversity, indicating the critical significance of an open canopy for butterflies. Though riparian forests need greater attention concerning butterfly distribution, maintaining open and dense forests are crucial for preserving butterfly diversity.
View
... 20°50′, lat. 40°21′; maximum elevation 2,520 m) is located in NW Greece ( Figure S1, Table S1, but see also Zografou, Wilson, Halley, Tzirkalli and Kati (2017) for detailed descriptions). Both systems share a low human population density and associated low-intensity human activities, as well as high coverage by protected areas of the Natura 2000 network. ...
... The minimum distance between nearest neighboring sites was approximately 2 km (SD ± 0.5) so that each site effectively represents an independent sampling unit. The lack of spatial autocorrelation between nearby sites was verified in terms of alpha and beta components of diversity in a previous study where we investigated diversity patterns of butterflies and Orthoptera across different spatial scales (Zografou et al., 2017). Each mountain was partitioned into four elevation zones (0-500 m, 501-1,000 m, 1,001-1,500 m, and 1,501-2,000 m) and each zone contained sites representing the three dominant habitats found in the study system (agricultural fields, grasslands, and forests), with the exception that agricultural areas were not present above 1,500 m ( Figure S1, Table S1). ...
Butterfly phenology in Mediterranean mountains using space‐for‐time substitution
Article
Full-text available
  • Jan 2020
Abstract Inferring species' responses to climate change in the absence of long‐term time series data is a challenge, but can be achieved by substituting space for time. For example, thermal elevational gradients represent suitable proxies to study phenological responses to warming. We used butterfly data from two Mediterranean mountain areas to test whether mean dates of appearance of communities and individual species show a delay with increasing altitude, and an accompanying shortening in the duration of flight periods. We found a 14‐day delay in the mean date of appearance per kilometer increase in altitude for butterfly communities overall, and an average 23‐day shift for 26 selected species, alongside average summer temperature lapse rates of 3°C per km. At higher elevations, there was a shortening of the flight period for the community of 3 days/km, with an 8.8‐day average decline per km for individual species. Rates of phenological delay differed significantly between the two mountain ranges, although this did not seem to result from the respective temperature lapse rates. These results suggest that climate warming could lead to advanced and lengthened flight periods for Mediterranean mountain butterfly communities. However, although multivoltine species showed the expected response of delayed and shortened flight periods at higher elevations, univoltine species showed more pronounced delays in terms of species appearance. Hence, while projections of overall community responses to climate change may benefit from space‐for‐time substitutions, understanding species‐specific responses to local features of habitat and climate may be needed to accurately predict the effects of climate change on phenology.
View
... For these reasons, Orthoptera have been used as bioindicators for conservation management [15,16] and its efficiency evaluation [17][18][19][20][21]. Greece is a hotspot for European Orthoptera fauna [22,23], hosting over one-third of all European species (35%: 378 species), with a pronounced degree of endemism (37%) and a number of red-listed species under the IUCN criteria (37%) [24,25]. However, the ecological knowledge base for Orthoptera communities is poor in Greece and is restricted to a few case studies (e.g., [15,[26][27][28]). ...
Orthoptera Community Dynamics and Conservation in a Natura 2000 Site (Greece): The Role of Beta Diversity
Article
Full-text available
  • Dec 2023
  • Diversity
Greece is a European hotspot for Orthoptera (378 species), yet it has been scarcely explored. We investigated the diversity patterns of Orthoptera and the ecological mechanisms shaping them by sampling 15 sites (30 plots of 1ha) across five habitats in Mount Mitsikeli, a Natura 2000 site. The mountain is deemed rich (0.4 species/km 2), hosting 34 species, including a species of European interest (Paracaloptenus caloptenoides). The grassy openings in the beech-fir forest and rural mosaics were found to be important habitats for Orthoptera, while the mountain grasslands were poorer but hosted a greater abundance of grasshoppers. The three main environmental factors shaping diversity patterns (with an explained variance of 51.34%) were grass height, the cover of woody vegetation and the cover of bare ground. Beta diversity was high (with a Bray-Curtis of index 0.45 among habitats). Species turnover prevailed among all sites and within agricultural land, beech-fir forest and Mediterranean scrub, while nested patterns prevailed within mountain grasslands and mixed thermophilous forest. Conservation actions should target sites in ecosystems driven by species turnover, but primarily the most species-rich sites are driven by nestedness. Such actions should include the implementation of biodiversity-inclusive grazing schemes to hamper forest encroachment and the restoration of mountain grassland quality from cattle overgrazing.
View
... Relatively large mountain ranges with diverse geological structure and climate (from Continental to Mediterranean) make south-eastern Europe an interesting region for studies of elevation gradients in species diversity. At the same time, data on butterfly diversity in this region is scattered in a multitude of faunistic papers, while few studies address the butterfly diversity pattern (Mihoci et al., 2011;Zografou et al., 2014Zografou et al., , 2017Kaltsas et al., 2018). Similarly, the effect of aspect is only rarely taken into consideration when addressing the distribution patterns of butterflies in mountains (Gutiérrez, 1997;Mihoci et al., 2011). ...
Effects of elevation gradient and aspect on butterfly diversity on Galičica Mountain in the Republic of Macedonia (south–eastern Europe)
Article
Full-text available
  • Dec 2020
Efectos del gradiente de altitud y la orientación en la diversidad de mariposas de la montaña Galičica, en la República de Macedonia (Europa sudoriental) Los patrones de diversidad de mariposas y los cambios en las comunidades en relación con la altitud son un tema interesante y bien estudiado en ecología, pero los efectos de la orientación se han evaluado muy poco. En el presente estudio analizamos los cambios en la riqueza de especies de mariposas y sus comunidades a lo largo del gradiente de altitud y según la orientación de la montaña Galičica. De acuerdo con lo esperado, la riqueza de especies cambió con la altitud siguiendo un patrón bimodal con los máximos y una tendencia decreciente hacia mayores altitudes. Los cambios estuvieron bien correlacionados con la superficie de cada zona de altitud, mientras que los efectos de la productividad fueron menos evidentes. Las comunidades de mariposas a mayor altitud fueron las más peculiares cuando se agruparon según las estimaciones de la diversidad beta, seguidas de las comunidades a media altitud y a baja altitud. Se observaron especies indicadoras en altitudes medias y en la combinación de altitudes medias bajas y medias altas, pero no entre las orientaciones. En general, la orientación produjo un efecto menos concluyente en la riqueza de especies y la composición de las comunidades. La mayor parte de estas diferencias se produjeron en el norte y en el sur, a pesar de que las laderas de la montaña están predominantemente orientadas al oeste y el este. El índice de temperatura comunitaria disminuyó con la altitud y en la orientación norte, lo que pone de manifiesto que estas zonas albergaban más especies adaptadas al frío. Se proporcionan notas sobre la conservación de las mariposas, ya que recientemente no se han registrado 23 de las especies observadas en estudios históricos. Datos publicado en GBIF (Doi: 10.15470/jacl7y).
View
... Evidence from insect distributions appears to contradict the distance limitation hypothesis. The spatial variation in species composition is higher among nearby bioclimatic belts along elevation gradients than among mountain systems separated by large distances (e.g., butterflies and orthopterans in Grammos and Rodopi separated by 426 km: Zografou et al. 2017; ground-dwelling beetles on mountains in north-western Patagonia separated by 40-100 km: Werenkraut and Ruggiero 2013; ants in Hengduan mountains, China: Liu et al. 2017). These studies suggest that, on a regional scale, the variation in mountain insect assemblages may be associated more with adaptation of species to local environmental conditions than by dispersal limitation imposed by distance (e.g., ants: Liu et al. 2017). ...
Environmental heterogeneity, not distance, structures montane epigaeic spider assemblages in north-western Patagonia (Argentina)
Article
Full-text available
  • Dec 2017
  • J INSECT CONSERV
There is considerable controversy around the patterns and processes that influence spatial variation in taxonomic composition in mountain environments. We analysed elevational variation in the taxonomic composition of epigaeic spider assemblages across five mountains in north-western Patagonia (Argentina) to examine the relative importance of dispersal (distance) limitation and environmental heterogeneity on a regional scale. The distance limitation hypothesis predicts greater taxonomic similarity between sampling sites separated by short geographical distances than between mountain peaks separated by longer distances, a lack of indicator species of macro-habitats, and weak associations between spider species composition and environmental gradients. Alternatively, the environmental heterogeneity hypothesis predicts that taxonomic differentiation will occur over short distances along elevation gradients in association with the turnover in major habitats and change in environmental conditions, and that indicator species will be present. We collected spiders using 486 pitfall traps arranged in fifty-four 100-m² grid plots of nine traps separated by ~ 100 m of elevation, from the base to the summit of each mountain. Multivariate analyses identified spider assemblages that were associated with macro-habitats rather than with mountains. Local environmental variation (mainly in vegetation cover), precipitation and soil characteristics influenced the spatial variation in species composition. Characteristic indicator species showed high specificity and fidelity to macro-habitats, whereas vulnerable species showed high specificity and low fidelity to mountains or macro-habitats. We conclude that, on a regional scale, species adaptation to environmental gradients plays a more important role than dispersal limitation in structuring the taxonomic composition of spider assemblages. Moreover, the presence of indicator species suggests that spiders have a great potential as ecological indicators for evaluating the response of montane biodiversity to future climatic change.
View
Micro‐ and macroclimate interactively shape diversity, niches and traits of Orthoptera communities along elevational gradients
Article
Full-text available
Aim Temperature is one of the main drivers shaping species diversity and assembly processes. Yet, site‐specific effects of the local microclimate on species and trait compositions of insect communities have rarely been assessed along macroclimatic temperature clines. Location Bavarian Alps, Germany. Methods Bayesian joint species distribution models were applied to investigate how ecological and morphological traits drive variation in the climatic niches of 32 Orthoptera species on 93 grassland sites with contrasting microclimatic conditions along a steep elevational macroclimatic gradient in an Alpine region in Central Europe. Results Species richness and abundance decreased along the elevational macroclimatic gradient, and both benefitted from warm microclimate. Interactive effects of elevation and microclimate on the abundance were, however, species‐specific, and partly mediated by traits: Warm microclimatic conditions facilitated the occurrence of demanding xerophilic and late‐hatching species, resulting in marked community dissimilarities at mid‐elevations where colder sites harboured only a subset of the species. The latter mainly occurred at low elevations together with long‐winged species. Abundance peaks of non‐xerophilic species were further upslope when microclimate was warm. Intraspecifically, the body sizes and wing lengths of the larger females, but not the males, decreased with elevation akin the community mean, and brown colour morphs were more frequent at sites with warm microclimate. Main Conclusions Our nuanced results reveal that trait‐dependent responses of species to microclimate play a key role in the assembly and structuring of insect communities along macroclimatic gradients. Since microclimate preferences changed with elevation, we conclude that species temperature niches are narrower than the elevational range suggests and both macro‐ and microclimatic conditions must be considered when predicting species responses to climate change. Microclimatic contrasts among sites at similar elevations enhanced species turnover mediated by moisture preferences and phenology, highlighting the importance of mountains for conservation as climatic refugia where species with diverging niches can persist in proximity.
View
Non-flying and flying macroinvertebrates show similar beta diversity patterns caused by different factors at two spatial scales in Amazon streams
Article
  • Oct 2021
We evaluated the beta diversity patterns of aquatic macroinvertebrate assemblages at two spatial scales in streams in the Eastern Amazon, as well as tested whether environmental and spatial factors affected these assemblage patterns differently for non-flying (i.e., shrimps) and flying (i.e., insects) macroinvertebrate groups. Fifteen streams were sampled, focusing on two hierarchical spatial levels: sampling units (length: five meters) and stream sites (length: 150 m). We additively partitioned gamma diversity to test the relative importance of each spatial level to regional diversity. The total beta diversity at each spatial level was decomposed into the components of replacement and abundance difference. To test whether there was an effect of spatial distances and environmental variables on the dissimilarity matrices, we used multiple regression on distance matrices (MRM). Our results showed that: (1) In both macroinvertebrate groups, alpha diversity contributed less than beta diversity, and dissimilarity between stream sites presented a greater contribution to gamma diversity; (2) the decomposition of beta diversity showed similar patterns in both groups and between the two spatial levels, with a greater contribution of abundance difference than replacement; and (3) the MRM models showed that only environmental distance was important to explain beta diversity of insects, while for shrimps both environmental and spatial distances were significant. We conclude that different ecological processes and environmental variables were important to explain the distributions of insects and shrimps, which is probably related to the different dispersal modes and environmental niche requirements.
View
Experimental evidence for density-determined wing dimorphism in two bush-crickets (Ensifera: Tettigoniidae)
Article
Full-text available
  • Nov 2009
Macroptery is common in many species of Orthoptera, but the causes are still discussed. Besides the assumption that macroptery is genetically determined, there is evidence that wing dimorphism is induced by environmental factors, particularly population density. However, most of the research is on pest species. In contrast, knowledge of wing dimorphism in species that occur at low population densites is still poor. Our study aims to test how density actually affects macroptery. As model organisms we chose two bush-cricket species of the genus Metrioptera (Ensifera: Tettigoniidae): While long-winged M. roeselii (Hagenbach, 1822) occur regularly, macropterous M. brachyptera (Linnaeus, 1761) are rare and are never observed outside their mating habitat. Nymphs of populations from the range core of both species (340 individuals each) were reared in groups of three and six individuals per 500 cm3 box, and individually. Our analyses revealed that development of macropters was mainly affected by the initial rearing densities. Compared with those reared individually the number of macropters was significantly higher among individuals reared at medium and high densities. The percentage of macropterous individuals was about twice as high in M. brachyptera as in M. roeselii, and the development of macropters significantly differed between the two species. These findings lead to the conclusion that macropterism is mainly influenced by density stress in both bush-crickets. Genetically determined wing dimorphism is unlikely, otherwise the observed high numbers of long-winged individuals of M. brachyptera, which are very rare under natural conditions, would never have developed in the laboratory. Macropterous M. brachyptera may rarely be found in the field, but we argue that this is due to low natural densities and, accordingly, to rare exposure to density stress.
View
View
View
The impact of low temperatures in controlling the geographical distribution of plants
Article
  • Jan 1990
The distribution limtis of three species in the British Isles are discussed. For Verbena officinalis and Tilia cordata low temperatures influence distribution by limiting the capacity either to flower or to fertilize ovules, respectively. In the case of Umbilicus rupestris, a long-term transplant population beyond the natural geographical limit of the species has evolved new low-temperature responses of seed germination and winter survival. The effect is a marked change of phenology, compared with populations of the species within its natural range, which enhances the capacity of the population to survive in a colder environment. There is a discussion by G.E.Fogg and U.Heber. -Author
View
View
Multiple Scales of Patchiness and Patch Structure: A Hierarchical Framework for the Study of Heterogeneity
Article
  • Nov 1990
We develop a hierarchical model of heterogeneity that provides a framework for classifying patch structure across a range of scales. Patches at lower levels in the hierarchy are more simplistic and correspond to the traditional view of patches. At levels approaching the upper bounds of the hierarchy the internal structure becomes more heterogeneous and boundaries more ambiguous. At each level in the hierarchy, patch structure will be influenced by both contrast among patches as well as the degree of aggregation of patches at lower levels in the hierarchy. We apply this model to foraging theory, but it has wider applications as in the study of habitat selection, population dynamics, and habitat fragmentation. It may also be useful in expanding the realm of landscape ecology beyond the current focus on anthropocentric scales.
View
Mixed Effect Models and Extensions in Ecology With R
Book
  • Jan 2009
Limitations of linear regression applied on ecological data. - Things are not always linear additive modelling. - Dealing with hetergeneity. - Mixed modelling for nested data. - Violation of independence - temporal data. - Violation of independence spatial data. - Generalised linear modelling and generalised additive modelling. - Generalised estimation equations. - GLMM and GAMM. - Estimating trends for Antarctic birds in relation to climate change. - Large-scale impacts of land-use change in a Scottish farming catchment. - Negative binomial GAM and GAMM to analyse amphibian road killings. - Additive mixed modelling applied on deep-sea plagic bioluminescent organisms. - Additive mixed modelling applied on phyoplankton time series data. - Mixed modelling applied on American Fouldbrood affecting honey bees larvae. - Three-way nested data for age determination techniques applied to small cetaceans. - GLMM applied on the spatial distribution of koalas in a fragmented landscape. - GEE and GLMM applied on binomial Badger activity data.
View
Measuring Biological Diversity
Book
  • Jul 2004
"Measuring Biological Diversity assumes no specialist mathematical knowledge and includes worked examples and links to web-based software. It will be essential reading for all students, researchers, and managers who need to measure biological diversity."--BOOK JACKET.
View
View
The Impact of Low Temperatures in Controlling the Geographical Distribution of Plants: Discussion
Article
The distribution limits of three species, in the British Isles are discussed. For Verbena officinalis and Tilia cordata low temperatures are shown to influence distribution, by limiting the capacity either to flower or to fertilize ovules, respectively. In the case of Umbilicus rupestris, a long-term transplant population beyond the natural geographical limit of the species has evolved new low-temperature responses of seed germination and winter survival. The effect is a marked change of phenology, compared with populations of the species within its natural range, which enhances the capacity of the population to survive in a colder environment.
View