Metapopulation dynamics and distribution, and environmental heterogeneity induced by niche construction (original) (raw)
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Effects of time-lagged niche construction on metapopulation dynamics and environmental heterogeneity
Applied Mathematics and Computation, 2009
Time-delayed responses to environmental changes and disturbance can beget profound effects on the spatiotemporal dynamics of metapopulations. Here, we first examined the effect of three forms of time-lag (that is, equal-weight, recency and primacy effects) on population dynamics, using a spatially structured lattice model. The time-lag was incorporated in the niche construction process of the system (an organism-environment feedback). Using bifurcations diagrams and numerical simulations, we found that the time-lag can form a phase-locked oscillation. Three typical spatial patterns emerged: spiral wave, spiral-broken wave and circular wave. These spatial patterns gradually become immobile as a result of the self-organized ecological imprinting due to niche construction. Therefore, the phase-locked oscillation and the ecological imprinting process together determine the spatial structure of metapopulations and the environmental heterogeneity.
Nestedness, niche metrics and temporal dynamics of a metacommunity in a dynamic natural model system
Oikos, 2008
Prediction of extinction and colonization rates for whole species assemblages emerges as an urgent task for ecology. We hypothesized that nestedness of species assemblage reflects differential ability of species to occupy sites and of sites to support species. If correct, a nested ordering of species and sites should condense long-term dynamics of metacommunities. To test this we characterized the differential ability of species to use habitat (niche position and niche breadth) using eight surveys of invertebrate communities inhabiting 49 tropical rock pools. We examined temporal consistency of the nested rank of species and pools, and related them to species and pool characteristics to infer temporal dynamics of species composition. Invertebrate assemblages in the rock-pools were significantly nested and species ranks were generally preserved over time. By contrast, pool ranks were usually conserved between adjacent years only but their similarity declined with time separating surveys. The nested species-by-pool matrix of the first survey served as a benchmark to assess individual species and local community changed in subsequent years. As hypothesized, benchmark cells with high state occupancy probability had low extinction rates in subsequent years. Moreover, species high in the nested matrix (also with high regional occupancy probability) were better survivors and colonizers relative to species that ranked low. The year-to-year dynamics were similar. Species with non-marginal niche position retained high ranks in the matrix. Yet, niche position predicted only colonization rate of species. Niche breadth and species' nested ranking, extinction risk, or ability to colonize a pool showed no relationship. Counter to the expectation, pool ranks did not predict species extinction and colonization rates. Apparently, even in dynamic systems, regional nested pattern remains consistent and the underlying extinction and colonization dynamics appear to be largely determined by the hierarchical order among species and much less by that among sites.
Disturbance-generated niche-segregation in a structured metapopulation model
Question: Does limiting similarity apply for coexistence maintained by disturbance in a metapopulation? Methods: In contrast to patch occupancy modeling, we follow both local-and metapopulation-scale dynamics explicitly. The theory of structured metapopulations is used for this purpose. Adaptive dynamics is employed to study evolution. Key assumptions: Local catastrophes at a given rate. Fixed dispersal rate, trade-off between fecundity and local competitivity. Results: Coexistence of a few (up to 5), but not more species is observed. They are distinctly different along the trade-off variable and partition the patch-age axis. Series of evolutionary branchings leads to an evolutionary stable coalition. Conclusions: The usual niche theoretical picture of decreased competition with increased differentiation applies. The patch-age is the proper niche axis. Niche differentiation along this axis is the requirement of coexistence. Constraints of coexistence is overlooked in patch occupancy models.
Ecography, 2020
Rapid changes in species composition, also known as ecotones, can result from various causes including rapid changes in environmental conditions, or physiological thresholds. The possibility that ecotones arise from ecological niche construction by ecosystem engineers has received little attention. In this study, we investigate how the diversity of ecosystem engineers, and their interactions, can give rise to ecotones. We build a spatially explicit dynamical model that couples a multispecies community and its abiotic environment. We use numerical simulations and analytical techniques to determine the biotic and abiotic conditions under which ecotone emergence is expected to occur, and the role of biodiversity therein. We show that the diversity of ecosystem engineers can lead to indirect interactions through the modification of their shared environment. These interactions, which can be either competitive or mutualistic, can lead to the emergence of discrete communities in space, separated by sharp ecotones where a high species turnover is observed. Considering biodiversity is thus critical when studying the influence of species-environment interactions on the emergence of ecotones. This is especially true for the wide range of species that have small to moderate effects on their environment. Our work highlights new mechanisms by which biodiversity loss could cause significant changes in spatial community patterns in changing environments.
Ecological Modelling, 2009
Several models have been proposed to understand how so many species can coexist in ecosystems. Despite evidence showing that natural habitats are often patchy and fragmented, these models rarely take into account environmental spatial structure. In this study we investigated the influence of spatial structure in habitat and disturbance regime upon species' traits and species' coexistence in a metacommunity. We used a population-based model to simulate competing species in spatially explicit landscapes. The species traits we focused on were dispersal ability, competitiveness, reproductive investment and survival rate. Communities were characterized by their species richness and by the four life-history traits averaged over all the surviving species. Our results show that spatial structure and disturbance have a strong influence on the equilibrium life-history traits within a metacommunity. In the absence of disturbance, spatially structured landscapes favour species investing more in reproduction, but less in dispersal and survival. However, this influence is strongly dependent on the disturbance rate, pointing to an important interaction between spatial structure and disturbance. This interaction also plays a role in species coexistence. While spatial structure tends to reduce diversity in the absence of disturbance, the tendency is reversed when disturbance occurs. In conclusion, the spatial structure of communities is an important determinant of their diversity and characteristic traits. These traits are likely to influence important ecological properties such as resistance to invasion or response to climate change, which in turn will determine the fate of ecosystems facing the current global ecological crisis.
Niche emergence as an autocatalytic process in the evolution of ecosystems
Journal of Theoretical Biology
The utilisation of the ecospace and the change in diversity through time has been suggested to be due to the effect of niche partitioning, as a global long-term pattern in the fossil record. However, niche partitioning, as a way to coexist, could be a limited means to share the environmental resources and condition during evolutionary time. In fact, a physical limit impedes a high partitioning without a high restriction of the niche's variables. Here, we propose that niche emergence, rather than niche partitioning, is what mostly drives ecological diversity. In particular, we view ecosystems in terms of autocatalytic sets: catalytically closed and selfsustaining reaction (or interaction) networks. We provide some examples of such ecological autocatalytic networks, how this can give rise to an expanding process of niche emergence (both in time and space), and how these networks have evolved over time (so-called evoRAFs). Furthermore, we use the autocatalytic set formalism to show that it can be expected to observe a power-law in the size distribution of extinction events in ecosystems. In short, we elaborate on our earlier argument that new species create new niches, and that biodiversity is therefore an autocatalytic process.
Proceedings of the Royal Society B: Biological Sciences
Linking local to regional ecological and evolutionary processes is key to understand the response of Earth's biodiversity to environmental changes. Here we integrate evolution and mutualistic coevolution in a model of metacommunity dynamics and use numerical simulations to understand how coevolution can shape species distribution and persistence in landscapes varying in space and time. Our simulations show that coevolution and species richness can synergistically shape distribution patterns by increasing colonization and reducing extinction of populations in metacommunities. Although conflicting selective pressures emerging from mutualisms may increase mismatches with the local environment and the rate of local extinctions, coevolution increases trait matching among mutualists at the landscape scale, counteracting local maladaptation and favouring colonization and range expansions. Our results show that by facilitating colonization, coevolution can also buffer the effects of env...
Niche construction, co-evolution and biodiversity
Ecological Economics, 2010
Many organisms modulate the availability of resources to other species, in the process changing the selection to which they and other organisms are exposed (niche construction).
Disturbance, interspecific interaction and diversity in metapopulations
Metapopulation diversity patterns depend on the relations among the timescales of local biological interactions (predation, competition), the rates of dispersal among local populations and the patterns of disturbance. We investigatc these relationships using a family of simple non-linear Markov chain models. We consider three models for interspecific competition; if the species are identified with early and late successional spccies, the models describe the facilitation, inhibition and tolerance modcls of ecological succession. By adding a third competing species we also compare transitive competitive hierarchies and intransitive competitive networks. Finally, we examine the effects of predation in mediating coexistence among competing prey species. In each model we find circumstances in which biotic or abiotic disturbance ran increase both local and regional diversity, but those circumstances depend on the various timescales in the model in ways that arc neither obvious nor trivial.