ArticlePDF Available

First evidence for long-term stasis in wet-tropics land snail community composition

  • Pre-Construct Archaeology

Abstract and Figures

While spatial turnover in species composition is well documented (Whittaker 1975; Condit et al. 2002) much less investigation has been conducted over long‐time periods. Land snails provide a unique window to observe such patterns because their fossil shells not only allow for species‐level identifications and quantification of abundance (Schilthuizen 2011), but can also provide accurate radioisotope dates (Pigati et al. 2010). Here we compare species turnover and accumulation patterns in comparable temperate (Slovakia and the Czech Republic) and tropical (Malaysian Borneo) land snail datasets. These analyses show that while temperate communities demonstrated significant compositional change over the modern to Late Glacial Maximum (LGM) transition, tropical communities did not. This article is protected by copyright. All rights reserved.
Content may be subject to copyright.
© 2018 e Authors. Ecography © 2018 Nordic Society Oikos
Subject Editor:
Jens-Christian Svenning
Editor-in-Chief: Miguel Araújo
Accepted 4 October 2018
00: 1–3, 2018
doi: 10.1111/ecog.03996
doi: 10.1111/ecog.03996 00 1–3
While spatial turnover in species composition is well documented (Whittaker 1975,
Condit et al. 2002) much less investigation has been conducted over long-time peri-
ods. Land snails provide a unique window to observe such patterns because their fossil
shells not only allow for species-level identifications and quantification of abundance
(Schilthuizen 2011), but can also provide accurate radioisotope dates (Pigati et al.
2010). Here we compare species turnover and accumulation patterns in comparable
temperate (Slovakia and the Czech Republic) and tropical (Malaysian Borneo) land
snail datasets. ese analyses show that while temperate communities demonstrated
significant compositional change over the modern to Late glacial maximum (LGM)
transition, tropical communities did not.
Dissimilarity in both datasets was driven by species turnover (0.74 versus 0.65 for
temperate versus tropics) rather than by differences in richness (0.13 versus 0.07).
Highly significant temporal distance decay (DD) in species composition was noted
(Fig. 1) for the temperate dataset (p << 0.0001) while no significant decay was noted
over the same period in the tropics (p = 0.28). us while over 70% of observed
similarity decay was explained by temporal distance in Slovakia/Czech Republic, less
than 10% was explained in Malaysia. AICc value comparison in the temperate data
indicated that a two-parameter exponential form (–44.1) was much better fit to the data
than a two-parameter power-law form (–25.6). Important differences were also noted
in the shape of the species–time relationship (STR). While Slovakia/Czech Republic
data demonstrate a 78% cumulative increase of species over the modern-LGM axis,
the Malaysian data accumulated a dozen fewer species over the same temporal extent.
e tropical data also exhibited a more pronounced asymptote: while cumulative
temperate species richness demonstrated a 50% increase in cumulative richness from
0.3–25 ka, tropical richness only increased 20% over the same period.
ese analyses demonstrate that while there has been continual turnover in land
snail assemblages in the temperate system, the tropical system demonstrated compo-
sitional stasis. Observed turnover in the temperate system was expected given regional
biome change from the cold and dry LGM to wet and warm modern. Such directional
change in the regional species pool is supported by extensive fossil evidence (Ložek 1964)
and is further documented by the exponential form of the temporal DD relationship
(Nekola and McGill 2014). At least some turnover was expected from the Malaysian
First evidence for long-term stasis in wet-tropics land snail
community composition
Jeffrey C.Nekola, MennoSchilthuizen, KatherineSzabo, VeronikaHorsáková and MichalHorsák
J. C. Nekola ( (, V. Horsáková and M. Horsák, Dept of Botany and Zoology, Masaryk Univ.,
Kotlářská 2, CZ-611 37 Brno, Czech Republic. JCN also at: Biology Dept, Univ. of New Mexico, Albuquerque, NM 87131, USA. – M. Schilthuizen,
Naturalis Biodiversity Center, Leiden, the Netherlands, and: Inst. Biology Leiden, Leiden Univ., Leiden, the Netherlands. – K. Szabo, Max Planck Inst. for
the Science of Human History, Jena, Germany.
data, however, given known palynological changes from sea-
sonally dry to wet tropical forest over the analyzed temporal
extent (Jones et al. 2014). Yet, community similarity only
varied between 0.4–0.6 and demonstrated no significant trend
across 0.3–25 ka extents. ese similarity values are equiva-
lent to those observed between adjacent (10 km) modern karst
tower faunas at Simbaluylon and Tinahas, Malaysia (48 and
45 observed species, respectively, with 36 in common) and are
likely driven by stochastic differences between samples drawn
from the same regional pool (Preston 1962).
It is not immediately clear why land snail community
composition in the tropics has been more resilient to long-
term regional climate change than that observed for vascu-
lar plants in the same region. We hypothesize that this may
be related to the: 1) smaller habitat size required to sustain
minimally viable land snail populations – ranging down
to 10-m² areas for some microsnails (Schilthuizen 2011),
and/or 2) excellent passive dispersal abilities of many land
snails (Gittenberger et al. 2006) which allow them access to
even the most isolated refugia. us an archipelago of tiny
refugia within the karst-tower landscape may provide long-
term buffering against moderate temperature and consider-
able precipitation variability, helping maintain a uniform
regional species pool over long time scales. e temporal
turnover seen in the temperate zone, however, probably
reflects the greater total experienced temperature and precipi-
tation variation which exceeded the ability of such tiny, local
refugia to buffer regional climate change.
Lastly, even though land snail communities are among the
clearest examples known for neutral community assembly
(Schilthuizen 2011), we note that these data provide no clear
evidence for directional stochastic compositional change
(aka ‘ecological drift’ of Hubbell 2001) over time. us even
though such drift can be generated in mesocosm experiments
over short time scales (Gilbert and Levine 2017) it is unclear
that this process is important in natural systems.
Figure 1. Comparison of temporal community composition changes for central European temperate and Malaysian wet tropic land snail
communities. (Top row) Distance decay over the modern to LGM transition based on all pairwise sample comparisons. (Bottom row)
Species–time relationship across 0 (modern) to 25 ka extents.
Condit, R. et al. 2002. Beta-diversity in tropical forests. – Science
295: 666–669.
Gilbert, B. and Levine, J. M. 2017. Ecological drift and the distri-
bution of species diversity. – Proc. R. Soc. B 284: 20170507.
Gittenberger, E. et al. 2006. Molecular trails from hitch-hiking
snails. – Nature 439: 409.
Hubbell, S. P. 2001. e unified neutral theory of biodiversity and
biogeography. – Princeton Univ. Press.
Jones, S. E. et al. 2014. A Late Pleistocene record of climate and
environmental change from the northern and southern Kelabit
Highlands of Sarawak, Malaysian Borneo. – J. Quat. Sci. 29:
Ložek, V. 1964. Quartärmollusken der Tschechoslowakei. Rozpravy
Ústředního ústavu geologického, vol. 31. – Československá
akademie věd, Praha.
Nekola, J. C. and McGill, B. 2014. Scale dependency in the functional
form of the distance decay relationship. – Ecography 37: 309–320.
Pigati, J. S. et al. 2010. Radiocarbon dating of small terrestrial
gastropod shells in North America. – Quat. Geochronol. 5:
Preston, F. W. 1962. e canonical distribution of commonness
and rarity. – Ecology 43: 185–215, 410–432.
Schilthuizen, M. 2011. Community ecology of tropical forest
snails 30 years after Solem. – Contrib. Zool. 80: 1–15.
Whittaker, R. H. 1975. Communities and ecosystems. – MacMillan
Supplementary material (Appendix ecog-03996 at <www.>). Appendix 1–4.
ResearchGate has not been able to resolve any citations for this publication.
Full-text available
Ecological drift causes species abundances to fluctuate randomly, lowering diversity within communities and increasing differences among otherwise equivalent communities. Despite broad interest in ecological drift, ecologists have little experimental evidence of its consequences in nature, where competitive forces modulate species abundances. We manipulated drift by imposing 40-fold variation in the size of experimentally assembled annual plant communities and holding their edge-to-interior ratios comparable. Drift over three generations was greater than predicted by neutral models, causing high extinction rates and fast divergence in composition among smaller communities. Competitive asymmetries drove populations of most species to small enough sizes that demographic stochasticity could markedly influence dynamics, increasing the importance of drift in communities. The strong effects of drift occurred despite stabilizing niche differences, which cause species to have greater population growth rates when at low local abundance. Overall, the importance of ecological drift appears greater in non-neutral communities than previously recognized, and varies with community size and the type and strength of density dependence. © 2017 The Author(s) Published by the Royal Society. All rights reserved.
Full-text available
Citation: Vermeulen JJ, Liew TS, Schilthuizen M (2015) Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species. ZooKeys 531: 1–139. Abstract We present reviews of the Sabah (Malaysia, on the island of Borneo) species of the following problematical genera of land snails (Mollusca, Gastropoda): Acmella and Anaglyphula (Caenogastropoda: Assimineidae); Ditropopsis (Caenogastropoda: Cyclophoridae); Microcystina (Pulmonata: Ariophantidae); Philalanka and Thysanota (Pulmonata: Endodontidae); Kaliella, Rahula, (Pulmonata: Euconulidae); Trochomorpha and Geotrochus (Pulmonata: Trochomorphidae). Next to this, we describe new species in previously revised genera, such as Diplommatina (Diplommatinidae); Georissa (Hydrocenidae); as well as some new species of genera not revised previously, such as Japonia (Cyclophoridae); Durgella and Dyakia (Ariophantidae); Amphidromus, and Trachia (Camaenidae); Paralaoma (Punctidae); Curvella (Subulinidae). All descriptions are based on the morphology of the shells. We distinguish the following 48 new species: Acmella cyrtoglyphe, A. umbilicata, A.
This study investigates the effects of sample volume, resolution and accumulation time on the interpretation of a mollusc record from terrestrial deposits. We tested (i) if, and to what extent, small sample sizes impoverish the reconstructed mollusc species richness, and (ii) whether fine-resolution sampling is worth the effort. We analysed three mollusc sequences, covering continuously the entire Holocene, which were collected in a tufa-forming spring fen and differed in sample size and resolution. More than 36 000 specimens of 76 species were processed. Using a rarefaction method, we observed that different sample volumes had a significant effect on the recorded species richness in this type of environment, and 100-cm3 samples seemed to be sufficient for a reliable reconstruction in tufa deposits. Although the thickness of the sampled layers had no influence on the palaeoecological interpretation, we observed a shift in the mollusc diversity peak once different resolutions were applied. Furthermore, the layers of finer resolution allowed detailed radiocarbon dating and better understanding of trends in species dynamics. We also observed significant confounding relationships among the number of species, number of specimens and accumulation time that can be disentangled if a precise depth–age model is available.
The Middle Pleniglacial on the northern hemisphere is characterized by millennial scale, frequent, and high amplitude environmental climatic shifts. In loess-paleosol sequences (LPSs) the transition from the Lower (MIS 4) to the Middle Pleniglacial (MIS 3) was accompanied by significant erosion events, as recorded in various terrestrial archives across Central Europe. As a result, potentially existing paleosol horizons of the particular period have been widely erased from the LPSs and only little is known about pedogenesis in this vast area. This study tries to fill this gap in our knowledge through studying a pedo-sedimentary record from Bíňa, a site situated in a relatively poorly investigated area on the northwestern edge of the Carpathian Basin. We investigated a 12-m-high and more than 500-m-wide outcrop along the Hron River, where a well-structured sequence of fluvio-lacustrine sediments, paleosols, and loess is preserved. The paleoenvironmental development within the studied area is presented and discussed on the basis of soil micromorphology, rock-magnetic and geochemical measurements, grain size analyses, and a malacological record accomplished by luminescence dating. Based on the OSL dating of the central profile, the sequence provides a high resolution record of the time period 60-20. ka (MIS 3-MIS 2). The most developed paleosol horizons (Phaeozem and two Bw horizons of Gleyic Cambisols) were dated to the early stage of the MIS 3 (60-50. ka) and correlated with the Greenland interstadials GI-17/16, GI-14/13 and/or GI-12 (the northwestern European interstadials Oerel, Glinde and Moershoofd). The development of the Bw horizon of a Cambisol recorded within the younger loess body was dated to ca. 35. ka and it probably corresponds to the late MIS 3 intestadials GI-8-5 (Denekamp). The preservation as well as the development of the well-stratified record were closely related to the specific hydro- and geomorphological settings of the paleo-channel structure in which the sequence developed. Although soil development benefited from the specific local settings, we suggest that the recorded paleosols can also be related to the interregional climate differences of the Carpathian Basin: within the northerly located pericarpathian zones, a moister climate predominated during the last Pleniglacial, in contrast to the drier continental areas to the South. Thus, a sharp climatic transition existed separating a semi-arid steppe region from a climatic zone under the persistent influence of Atlantic air masses.
A late Pleistocene vegetation record is presented, using multi-proxy analysis from three palaeochannels in the northern (Bario) and southern (Pa'Dalih) Kelabit Highlands of Sarawak, Malaysian Borneo. Before 50 000 cal a BP and until ∼47 700 cal a BP [marine isotope stage 3 (MIS3)], two of the sites were probably being influenced by energetic fluvial deposition, possibly associated with strong seasonality. Fluvial activity declines between 47 700 and 30 000 cal a BP (MIS3), and may be associated with a reduction in seasonality with overall stability in precipitation. The pollen record between 47 700 and 30 000 cal a BP generally shows much higher representation of upper-montane taxa compared with the Holocene, indicating often significantly reduced temperatures. After 35 000–30 000 cal a BP and until the mid-Holocene, hiatuses appear in two of the records, which could be linked to fluvial down-cutting during the late/mid Holocene. Despite the jump in ages, a pronounced representation of Ericaceae and upper-montane taxa, represented both at Bario and at Pa'Dalih, corresponds to a further lowering of temperatures during the Last Glacial Maximum (MIS2). Thick charcoal bands in the PDH 210 record also suggest periods of extreme aridity between 30 200 and 12 700 cal a BP. This is followed by energetic fluvial deposition of sands and gravels, and may reflect a significant increase in seasonality.
We examine a novel mathematical approach which posits that the decay of similarity in community composition with increasing distance (aka distance decay) can be modeled as the sum of individual species joint-probability vs distance relationships. Our model, supported by analyses of these curves from three datasets (North American breeding birds, North American taiga plants, and tropical forest trees), suggest that when sampling grain is large enough to avoid absences due to stochastic sampling effects, and/or sampling extent is large enough to generate species turnover through the deterministic crossing of environmental and/or geographical range limits, species joint-probability over increasing distance will generally exhibit exponential decay. However, at small scales where occurrence is driven more by stochastic sampling effects, species joint-probability curves exhibit a power-law decay form. Lacking a theoretical prediction of how individual species joint-probability relationships combine to generate community distance decay, we also performed a meta-analysis of 26 ecological and 4 human-system datasets, using non-linear regression to mean and quantile non-linear regression at tau = 0.95 for linear, exponential, and power-law decay forms. These analyses demonstrate that the functional form of community distance decay – as shown by comparison of AIC ranks – is largely determined by observational scale, with power law decay prevailing within domains where the species pool remains constant, while exponential decay prevails at larger scales over which the species pool varies, paralleling the patterns predicted in our mathematical approach.