Predicting past distributions of species climatic niches, hindcasting, by using climate envelope models (CEMs) is emerging as an exciting research area. CEMs are used to examine veiled evolutionary ...questions about extinctions, locations of past refugia and migration pathways, or to propose hypotheses concerning the past population structure of species in phylogeographical studies. CEMs are sensitive to theoretical assumptions, to model classes and to projections in non-analogous climates, among other issues. Studies hindcasting the climatic niches of species often make reference to these limitations. However, to obtain strong scientific inferences, we must not only be aware of these potential limitations but we must also overcome them. Here, I review the literature on hindcasting CEMs. I discuss the theoretical assumptions behind niche modelling, i.e. the stability of climatic niches through time and the equilibrium of species with climate. I also summarize a set of 'recommended practices' to improve hindcasting. The studies reviewed: (1) rarely test the theoretical assumptions behind niche modelling such as the stability of species climatic niches through time and the equilibrium of species with climate; (2) they only use one model class (72% of the studies) and one palaeoclimatic reconstruction (62.5%) to calibrate their models; (3) they do not check for the occurrence of non-analogous climates (97%); and (4) they do not use independent data to validate the models (72%). Ignoring the theoretical assumptions behind niche modelling and using inadequate methods for hindcasting CEMs may well entail a cascade of errors and naïve ecological and evolutionary inferences. We should also push integrative research lines linking macroecology, physiology, population biology, palaeontology, evolutionary biology and CEMs for a better understanding of niche dynamics across space and time.
Ecology Letters (2011) 14: 484–492
Europe has the world’s most extensive network of conservation areas. Conservation areas are selected without taking into account the effects of climate change. How ...effectively would such areas conserve biodiversity under climate change? We assess the effectiveness of protected areas and the Natura 2000 network in conserving a large proportion of European plant and terrestrial vertebrate species under climate change. We found that by 2080, 58 ± 2.6% of the species would lose suitable climate in protected areas, whereas losses affected 63 ± 2.1% of the species of European concern occurring in Natura 2000 areas. Protected areas are expected to retain climatic suitability for species better than unprotected areas (P < 0.001), but Natura 2000 areas retain climate suitability for species no better and sometimes less effectively than unprotected areas. The risk is high that ongoing efforts to conserve Europe’s biodiversity are jeopardized by climate change. New policies are required to avert this risk.
Processes leading to range contractions and population declines of Arctic megafauna during the late Pleistocene and early Holocene are uncertain, with intense debate on the roles of human hunting, ...climatic change, and their synergy. Obstacles to a resolution have included an overreliance on correlative rather than process‐explicit approaches for inferring drivers of distributional and demographic change. Here, we disentangle the ecological mechanisms and threats that were integral in the decline and extinction of the muskox (Ovibos moschatus) in Eurasia and in its expansion in North America using process‐explicit macroecological models. The approach integrates modern and fossil occurrence records, ancient DNA, spatiotemporal reconstructions of past climatic change, species‐specific population ecology, and the growth and spread of anatomically modern humans. We show that accurately reconstructing inferences of past demographic changes for muskox over the last 21,000 years require high dispersal abilities, large maximum densities, and a small Allee effect. Analyses of validated process‐explicit projections indicate that climatic change was the primary driver of muskox distribution shifts and demographic changes across its previously extensive (circumpolar) range, with populations responding negatively to rapid warming events. Regional analyses show that the range collapse and extinction of the muskox in Europe (~13,000 years ago) was likely caused by humans operating in synergy with climatic warming. In Canada and Greenland, climatic change and human activities probably combined to drive recent population sizes. The impact of past climatic change on the range and extinction dynamics of muskox during the Pleistocene–Holocene transition signals a vulnerability of this species to future increased warming. By better establishing the ecological processes that shaped the distribution of the muskox through space and time, we show that process‐explicit macroecological models have important applications for the future conservation and management of this iconic species in a warming Arctic.
We reconstructed 21,000 years of climate‐ and human‐driven range dynamics of muskox by integrating modern occurrence records, fossil records, paleoclimate reconstructions, ancient DNA sequences, human expansion models and spatially explicit process‐explicit macroecological models. Models that could reconcile inferences of demographic change from fossils were used to determine the likely chains of causality responsible for the contemporary distribution of muskox. We show that climatic change was a primary driver of the structure and dynamics of the distribution of muskox, with human activities, and their interactions with climatic changes, being important in some regions.
How individual species and entire ecosystems will respond to future climate change are among the most pressing questions facing ecologists. Past biodiversity dynamics recorded in the paleoecological ...archives show a broad array of responses, yet significant knowledge gaps remain. In particular, the relative roles of evolutionary adaptation, phenotypic plasticity, and dispersal in promoting survival during times of climate change have yet to be clarified. Investigating the paleo-archives offers great opportunities to understand biodiversity responses to future climate change. In this review we discuss the mechanisms by which biodiversity responds to environmental change, and identify gaps of knowledge on the role of range shifts and tolerance. We also outline approaches at the intersection of paleoecology, genomics, experiments, and predictive models that will elucidate the processes by which species have survived past climatic changes and enhance predictions of future changes in biological diversity.
The study of biodiversity responses to past climate change can greatly help us understand current threats and forecast future responses.
There is ample evidence of effective migration, in situ tolerance, and adaptation in response to past climate changes. But there is also evidence of widespread extinctions.
The unprecedented nature of modern global change greatly complicates prediction. Large uncertainties remain about the expected rates of migration and evolutionary adaptation, or the role of phenotypic plasticity in avoiding extinction.
Integrative research programmes combining paleorecords (e.g., fossils, ancient genomics) with mechanistic models and experiments (e.g., resurrection experiments) hold great promise to improve our understanding and predictive ability.
Aim
Most of the fundamental questions in conservation biogeography require the description of species geographic boundaries and the identification of discrete biological units within these ...boundaries. International conservation efforts and institutions rely mainly on traditional taxonomic approaches for defining these boundaries, resulting in significant cryptic diversity going undetected and often extinct. Here, we combine high‐throughput genomic data with publicly available environmental data to identify cryptic diversity in the threatened bird's‐eye primrose (Primula farinosa). We aim to characterize evolutionary lineages and test whether they co‐occur with changes in environmental conditions. These lineages can be used as intraspecific units for conservation to enhance assessments regarding the status of threatened species.
Location
Europe and temperate Asia (latitude, 40–65°N; longitude, 10°E–115°W).
Methods
We genotyped 93 individuals from 71 populations at 1,220 loci (4,089 SNPs) across the Eurasian distribution of P. farinosa. We used phylogenomic and population structure approaches to identify intraspecific lineages. We further extracted statistically derived and remotely sensed environmental information, that is land cover, climate and soil characteristics, to define the biotic and abiotic environment inhabited by each lineage and test for niche similarities among lineages. Additionally, we tested for isolation by distance among populations and applied linear and polynomial regressions to identify lineage‐environment associations.
Results
Analyses of genomic data revealed six major lineages within P. farinosa corresponding to distinct geographic areas. Niche similarity tests indicated that lineages occupy distinct abiotic and biotic space. Isolation by distance indicated that geography alone cannot explain genetic divergence within P. farinosa, while lineage‐environment associations suggested potential adaptation to different abiotic conditions across lineages. However, relationships with the land cover classes, a proxy for habitat, were weaker.
Main conclusion
Our results highlight the need for incorporating intraspecific diversity in global assessments of species conservation status and the utility of genomic and publicly available environmental data in conservation biogeography.
The structure of species interaction networks is important for species coexistence, community stability and exposure of species to extinctions. Two widespread structures in ecological networks are ...modularity, i.e. weakly connected subgroups of species that are internally highly interlinked, and nestedness, i.e. specialist species that interact with a subset of those species with which generalist species also interact. Modularity and nestedness are often interpreted as evolutionary ecological structures that may have relevance for community persistence and resilience against perturbations, such as climate-change. Therefore, historical climatic fluctuations could influence modularity and nestedness, but this possibility remains untested. This lack of research is in sharp contrast to the considerable efforts to disentangle the role of historical climate-change and contemporary climate on species distributions, richness and community composition patterns. Here, we use a global database of pollination networks to show that historical climate-change is at least as important as contemporary climate in shaping modularity and nestedness of pollination networks. Specifically, on the mainland we found a relatively strong negative association between Quaternary climate-change and modularity, whereas nestedness was most prominent in areas having experienced high Quaternary climate-change. On islands, Quaternary climate-change had weak effects on modularity and no effects on nestedness. Hence, for both modularity and nestedness, historical climate-change has left imprints on the network structure of mainland communities, but had comparably little effect on island communities. Our findings highlight a need to integrate historical climate fluctuations into eco-evolutionary hypotheses of network structures, such as modularity and nestedness, and then test these against empirical data. We propose that historical climate-change may have left imprints in the structural organisation of species interactions in an array of systems important for maintaining biological diversity.
An Anthropocene map of genetic diversity Miraldo, Andreia; Li, Sen; Borregaard, Michael K. ...
Science (American Association for the Advancement of Science),
09/2016, Volume:
353, Issue:
6307
Journal Article
Peer reviewed
The Anthropocene is witnessing a loss of biodiversity, with well-documented declines in the diversity of ecosystems and species. For intraspecific genetic diversity, however, we lack even basic ...knowledge on its global distribution. We georeferenced 92,801 mitochondrial sequences for >4500 species of terrestrial mammals and amphibians, and found that genetic diversity is 27% higher in the tropics than in nontropical regions. Overall, habitats that are more affected by humans hold less genetic diversity than wilder regions, although results for mammals are sensitive to choice of genetic locus. Our study associates geographic coordinates with publicly available genetic sequences at a massive scale, yielding an opportunity to investigate both the drivers of this component of biodiversity and the genetic consequences of the anthropogenic modification of nature.
Aims We present an analysis of grid-based species-richness data for European plants, mammals, birds, amphibians and reptiles, designed to test the proposition of Hawkins et al. (2003a) that the ...single best factor describing richness variation switches from the water regime to the energy regime in the mid-latitudes and that the 'breakpoint' is related to the physiological character of the taxa. We go on to develop subregional models showing the extent to which regional model fits vary as a function of the extent of the study system, and compare the relative performance of 'water', 'energy' and 'water-energy' models of richness for southern, northern and pan-European models. Location Western Europe. Methods We use atlas data comprising species range data for 187 species of mammals, 445 species of breeding birds, 58 amphibians, 91 reptiles and 2362 plant species, inserted into a c. 50 x 50 km grid cell system. We used 11 modelled climate variables, averaged for the period 1961-90. Statistical analyses were carried out using generalized additive models (GAMs), with splines simplified to a maximum of four degrees of freedom, and we tested for spatial autocorrelation using Moran's I values obtained at 10 different distance intervals. We selected favoured models on the grounds of deviance explained combined with a simple parsimony criterion, such that we selected either: (1) the best two-variable energy, water or water-energy model, or (2) a four-variable water-energy model, where the latter improved on the best two-variable model by a minimum of 5% deviance explained. Results Threshold energy values, at which richness shows a transition from an increasing to a decreasing function of annual solar radiation, were identified for all taxa apart from reptiles. We found conditional support for the switch from dominance of water variables (southern models) to energy variables (northern models). Our favoured models switched between 'water' and 'energy' for mammals, and between energy' and 'water-energy' for birds, depending on whether we used data of pan-European extent, southern or northern subsets. Deviance explained in our favoured models varied from 15% (birds, southern Europe) to 72% (amphibians, northern Europe), i.e. ranging from very poor to good fits with the data. Comparison with previous work indicates that our models are generally consistent with (if sometimes weaker than) previous findings. Main conclusions Our models are incomplete representations of factors influencing macro-scale richness patterns across Europe, taking no explicit account of, for example, topographic variation, human influences or long-term climatic variation. However, with the exception of birds, for which only the northern model attains over one-third deviance explained, the models show that climate can account for meaningful proportions of the deviance. We find general support for considering water and energy regimes together in modelling species richness, and for the proposition that water is more limiting in southern Europe and energy in the north. Our analyses demonstrate the sensitivity of model outcomes to the geographical location and extent of the study system, illustrating that simple curve-fitting exercises like these, particularly if based on regions with the complex history and geography characteristic of Europe, are unlikely to provide the basis for global, predictive models. However, such exercises may be of value in detecting which aspects of water and energy regimes may be of most importance in refining independently generated global models for regional application.
Rewilding — the proposed restoration of ecosystems through the (re-)introduction of species — is seen by many as a way to stem the loss of biodiversity and the functions and services that ...biodiversity provides to humanity. In addition, rewilding might lead to increased public engagement and enthusiasm for biodiversity. But what exactly is rewilding, and is it based on sound ecological understanding? Here, we show that there is a worrying lack of consensus about what rewilding is and what it isn’t, which jeopardizes a clearer account of rewilding’s aims, benefits and potential consequences. We also point out that scientific support for the main ecological assumptions behind rewilding, such as top-down control of ecosystems, is limited. Moreover, ecological systems are dynamic and ever-evolving, which makes it challenging to predict the consequences of introducing novel species. We also present examples of introductions or re-introductions that have failed, provoking unexpected negative consequences, and highlight that the control and extirpation of individuals of failed translocations has been shown to be extremely challenging and economically costly. Some of rewilding’s loudest proponents might argue that we are advocating doing nothing instead, but we are not; we are only advocating caution and an increased understanding and awareness of what is unknown about rewilding, and what its potential outputs, especially ecological consequences, might be.
Nogues-Bravo et al. take a critical look at rewilding, the idea to restore ecosystems through (re-)introduction of species.
This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean ...acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.
Transgression of planetary boundaries by human activities have now brought humanity well beyond a “safe operating space.”
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