How humans drive speciation as well as extinction

A central topic for conservation science is evaluating how human activities influence global species diversity. Humanity exacerbates extinction rates. But by what mechanisms does humanity drive the emergence of new species? We review human-mediated speciation, compare speciation and known extinctions, and discuss the challenges of using net species diversity as a conservation objective. Humans drive rapid evolution through relocation, domestication, hunting and novel ecosystem creation—and emerging technologies could eventually provide additional mechanisms. The number of species relocated, domesticated and hunted during the Holocene is of comparable magnitude to the number of observed extinctions. While instances of human-mediated speciation are known, the overall effect these mechanisms have upon speciation rates has not yet been quantified. We also explore the importance of anthropogenic influence upon divergence in microorganisms. Even if human activities resulted in no net loss of species diversity by balancing speciation and extinction rates, this would probably be deemed unacceptable. We discuss why, based upon ‘no net loss’ conservation literature—considering phylogenetic diversity and other metrics, risk aversion, taboo trade-offs and spatial heterogeneity. We conclude that evaluating speciation alongside extinction could result in more nuanced understanding of biosphere trends, clarifying what it is we actually value about biodiversity.

Download Full-text

Reconciliation ecology and the future of species diversity

Oryx ◽

10.1017/s0030605303000371 ◽

2003 ◽

Vol 37 (2) ◽

pp. 194-205 ◽

Cited By ~ 220

Author(s):

Michael L. Rosenzweig

Keyword(s):

Steady State ◽

Species Diversity ◽

Natural Area ◽

Reconciliation Ecology ◽

Anthropogenic Habitats ◽

Extinction Rates ◽

Broad Array ◽

Speciation Rates ◽

Species Area ◽

Biogeographical Province

Species-area relationships (SPARs) dictate a sea change in the strategies of biodiversity conservation. SPARs exist at three ecological scales: Sample-area SPARs (a larger area within a biogeographical province will tend to include more habitat types, and thus more species, than a smaller one), Archipelagic SPARs (the islands of an archipelago show SPARs that combine the habitat-sampling process with the problem of dispersal to an island), and Interprovincial SPARs (other things being equal, the speciation rates of larger biogeographical provinces are higher and their extinction rates are lower, leading to diversities in proportion to provincial area). SPARs are the products of steady-state dynamics in diversity, and such dynamics appears to have characterized the earth for most of the last 500 million years. As people reduce the area available to wild species, they impose a linear reduction of the earth's species diversity that will follow the largest of these scales, i.e. each 1% reduction of natural area will cost about 1% of steady-state diversity. Reserving small tracts of wild habitat can only delay these reductions. But we can stop most of them by redesigning anthropogenic habitats so that their use is compatible with use by a broad array of other species. That is reconciliation ecology. Many pilot projects, whether intentionally or inadvertently espousing reconciliation ecology, are demonstrating that it can be done.

Download Full-text

Hybridizing salamanders experience accelerated diversification

10.1101/760264 ◽

2019 ◽

Author(s):

Austin H. Patton ◽

Mark J. Margres ◽

Brendan Epstein ◽

Jon Eastman ◽

Luke J. Harmon ◽

...

Keyword(s):

Species Diversity ◽

Strong Evidence ◽

Diversification Rates ◽

Extinction Rates ◽

Speciation Rates ◽

Evolutionary Role ◽

Taxonomic Order

ABSTRACTWhether hybridization generates or erodes species diversity has long been debated, but to date most studies have been conducted at small taxonomic scales. Salamanders (order Caudata) represent a taxonomic order in which hybridization plays a prevalent ecological and evolutionary role. We employed a recently developed model of trait-dependent diversification to test the hypothesis that hybridization impacts the diversification dynamics of species that are currently hybridizing. We find strong evidence supporting this hypothesis, showing that hybridizing salamander lineages have significantly greater net-diversification rates than non-hybridizing lineages. This pattern is driven by concurrently increased speciation rates and decreased extinction rates in hybridizing lineages. Our results support the hypothesis that hybridization can act as a generative force in macroevolutionary diversification.

Download Full-text

Detecting hidden diversification shifts in models of trait-dependent speciation and extinction

10.1101/016386 ◽

2015 ◽

Cited By ~ 4

Author(s):

Jeremy M Beaulieu ◽

Brian C O'Meara

Keyword(s):

Empirical Data ◽

Diversification Rate ◽

Transition Rates ◽

Diversification Rates ◽

Extinction Rates ◽

State Dependent ◽

Speciation Rates ◽

Nuanced Understanding ◽

Hidden States ◽

Major Criticism

The distribution of diversity can vary considerably from clade to clade. Attempts to understand these patterns often employ state-dependent speciation and extinction models to determine whether the evolution of a particular novel trait has increased speciation rates and/or decreased their extinction rates. It is still unclear, however, whether these models are uncovering important drivers of diversification, or whether they are simply pointing to more complex patterns involving many unmeasured and co-distributed factors. Here we describe an extension to the popular state-dependent speciation and extinction models that specifically accounts for the presence of unmeasured factors that could impact diversification rates estimated for the states of any observed trait, addressing at least one major criticism of BiSSE methods. Specifically, our model, which we refer to as HiSSE (Hidden-State Speciation and Extinction), assumes that related to each observed state in the model are "hidden" states that exhibit potentially distinct diversification dynamics and transition rates than the observed states in isolation. We also demonstrate how our model can be used as character-independent diversification (CID) models that allow for a complex diversification process that is independent of the evolution of a character. Under rigorous simulation tests and when applied to empirical data, we find that HiSSE performs reasonably well, and can at least detect net diversification rate differences between observed and hidden states and detect when diversification rate differences do not correlate with the observed states. We discuss the remaining issues with state-dependent speciation and extinction models in general, and the important ways in which HiSSE provides a more nuanced understanding of trait-dependent diversification.

Download Full-text

Geographic contingency, not species sorting, dominates macroevolutionary dynamics in an extinct clade of neogastropods (Volutospina; Volutidae)

Paleobiology ◽

10.1017/pab.2020.60 ◽

2021 ◽

pp. 1-15

Author(s):

Dana S. Friend ◽

Brendan M. Anderson ◽

Warren D. Allmon

Keyword(s):

Middle Eocene ◽

Ecological Factors ◽

Geographic Range ◽

Late Eocene ◽

Range Size ◽

Species Sorting ◽

Extinction Rates ◽

Geographic Range Size ◽

Speciation Rates ◽

Planktotrophic Larvae

Abstract Rates of speciation and extinction are often linked to many ecological factors, traits (emergent and nonemergent) such as environmental tolerance, body size, feeding type, and geographic range. Marine gastropods in particular have been used to examine the role of larval dispersal in speciation. However, relatively few studies have been conducted placing larval modes in species-level phylogenetic context. Those that have, have not incorporated fossil data, while landmark macroevolutionary studies on fossil clades have not considered both phylogenetic context and net speciation (speciation–extinction) rates. This study utilizes Eocene volutid Volutospina species from the U.S. Gulf Coastal Plain and the Hampshire Basin, U.K., to explore the relationships among larval mode, geographic range, and duration. Based on the phylogeny of these Volutospina, we calculated speciation and extinction rates in order to compare the macroevolutionary effects of larval mode. Species with planktotrophic larvae had a median duration of 9.7 Myr, which compared significantly to 4.7 Myr for those with non-planktotrophic larvae. Larval mode did not significantly factor into geographic-range size, but U.S. and U.K. species do differ, indicating a locality-specific component to maximum geographic-range size. Non-planktotrophs (NPTs)were absent among the Volutospina species during the Paleocene–early Eocene. The relative proportions of NPTs increased in the early middle Eocene, and the late Eocene was characterized by disappearance of planktotrophs (PTs). The pattern of observed lineage diversity shows an increasing preponderance of NPTs; however, this is clearly driven by a dramatic extinction of PTs, rather than higher NPT speciation rates during the late Eocene. This study adds nuance to paleontology's understanding of the macroevolutionary consequences of larval mode.

Download Full-text

Rural–Urban Migration and Conservation Drive the Ecosystem Services Improvement in China Karst: A Case Study of HuanJiang County, Guangxi

Remote Sensing ◽

10.3390/rs13040566 ◽

2021 ◽

Vol 13 (4) ◽

pp. 566

Author(s):

Xiangkun Qi ◽

Qian Li ◽

Yuemin Yue ◽

Chujie Liao ◽

Lu Zhai ◽

...

Keyword(s):

Ecosystem Services ◽

Human Activities ◽

Soil Conservation ◽

Land Reclamation ◽

Vegetation Recovery ◽

Water Yield ◽

Urban Migration ◽

Trade Offs ◽

Rural Urban Migration ◽

Huanjiang County

Under the transformation from over-cultivation to ecological protection in China’s karst, how human activities affect ecosystem services should be studied. This study combined satellite imagery and ecosystem models (Carnegie-Ames-Stanford Approach (CASA), Revised Universal Soil Loss Equation (RUSLE) and Integrated Valuation of Ecosystem Services and Trade-offs (InVEST)) to evaluate primary ecosystem services (net ecosystem productivity (NEP), soil conservation and water yield) in a typical karst region (Huanjiang County). The relationships between human activities and ecosystem services were also examined. NEP increased from 441.7 g C/m2/yr in 2005 to 582.19 g C/m2/yr in 2015. Soil conservation also increased from 4.7 ton/ha to 5.5 ton/ha. Vegetation recovery and the conversion of farmland to forest, driven largely by restoration programs, contributed to this change. A positive relationship between increases in NEP, soil conservation and rural-urban migration (r = 0.62 and 0.53, P < 0.01, respectively) indicated decreasing human dependence on land reclamation and naturally regenerated vegetation. However, declining water yield from 784.3 to 724.5 mm highlights the trade-off between carbon sequestration and water yield should be considered. Our study suggests that conservation is critical to vegetation recovery in this region and that easing human pressure on land will play an important role.

Download Full-text

Biodiversity Offset Program Design and Implementation

Sustainability ◽

10.3390/su11246903 ◽

2019 ◽

Vol 11 (24) ◽

pp. 6903 ◽

Cited By ~ 4

Author(s):

Marie Grimm ◽

Johann Köppel

Keyword(s):

Program Design ◽

Landscape Scale ◽

Design And Implementation ◽

No Net Loss ◽

Regulatory Frameworks ◽

Biodiversity Offsets ◽

Trade Offs ◽

Mitigation Hierarchy ◽

Balance Development ◽

Biodiversity Offset

Biodiversity offsets are applied in many countries to compensate for impacts on the environment, but research on regulatory frameworks and implementation enabling effective offsets is lacking. This paper reviews research on biodiversity offsets, providing a framework for the analysis of program design (no net loss goal, uncertainty and ratios, equivalence and accounting, site selection, landscape-scale mitigation planning, timing) and implementation (compliance, adherence to the mitigation hierarchy, leakage and trade-offs, oversight, transparency and monitoring). Some more challenging aspects concern the proper metrics and accounting allowing for program evaluation, as well as the consideration of trade-offs when regulations focus only on the biodiversity aspect of ecosystems. Results can be used to assess offsets anywhere and support the creation of programs that balance development and conservation.

Download Full-text

TREE SPECIES DIVERSITY IN A PRISTINE MONTANE FOREST PREVIOUSLY UNTOUCHED BY HUMAN ACTIVITIES IN FOJA MOUNTAINS, PAPUA, INDONESIA

REINWARDTIA ◽

10.14203/reinwardtia.v17i2.3546 ◽

2018 ◽

Vol 17 (2) ◽

Author(s):

Asep Sadili ◽

Kuswata Kartawinata ◽

Herwasono Soedjito ◽

Edy Nasriadi Sambas

Keyword(s):

Species Diversity ◽

Tree Species ◽

Human Activities ◽

Diversity Index ◽

Basal Area ◽

Montane Forest ◽

Tree Species Diversity ◽

Importance Value ◽

Montane Forests ◽

Species Area

ADILI, A., KARTAWINATA, K., SOEDJITO, H. & SAMBAS, E. N. 2018. Tree species diversity in a pristine montane forest previously untouched by human activities in Foja Mountains, Papua, Indonesia. Reinwardtia 17(2): 133‒154. ‒‒ A study on structure and composition of the pristine montane forest previously untouched by human activities was conducted at the Foja Mountains in November 2008. We established a one-hectare plot divided into 100 subplots of 10 m × 10 m each. We enumerated all trees with DBH ≥ 10 cm which diameters were measured, heights were estimated and habitats were noted. We recorded 59 species, 42 genera and 27 families, comprising 693 trees with the total basal area (BA) of 41.35 m2/ha. The forest had lower species richness compared to those of lowland forests in Kalimantan, and Sumatra and montane forests in West Java. The Shannon-Wiener’s diversity index was 3.22. Nothofagus rubra (Importance Value, IV=47.89%) and Parinari corymbosa (IV=40.3%) were the dominant species, constituting the basis for designating the forest as the Nothofagus rubra - Parinari corymbosa association. To date, the dominance of N. rubra is unique to the Foja Mountains, as elsewhere in Papua the montane forests were dominated by N. pullei or other species. The species-area curve indicated a minimal area of 5000 m2. On the family level Fagaceae (IV=53.23%), Chrysobalanaceae (IV=40.53%) and Myristicaceae (IV=26.43%) were dominant. Verti-cally the forest consisted of four strata (A–D). In each stratum Nothofagus rubra, Platea latifolia, Parinari corymbosa and Myristica hollrungii were dominant. The diameter class distribution of Nothofagus rubra, Parinari corymbosa and Platea latifolia led us to assume that these species were regenerating well.

Download Full-text

Grazing resistance in phytoplankton

Hydrobiologia ◽

10.1007/s10750-020-04370-3 ◽

2020 ◽

Vol 848 (1) ◽

pp. 237-249 ◽

Cited By ~ 1

Author(s):

Miquel Lürling

Keyword(s):

Community Dynamics ◽

Phytoplankton Community ◽

Rapid Evolution ◽

Variable Environment ◽

Trade Off ◽

Defense Strategies ◽

Trade Offs ◽

Grazing Resistance ◽

Population And Community Dynamics

AbstractPhytoplankton is confronted with a variable assemblage of zooplankton grazers that create a strong selection pressure for traits that reduce mortality. Phytoplankton is, however, also challenged to remain suspended and to acquire sufficient resources for growth. Consequently, phytoplanktic organisms have evolved a variety of strategies to survive in a variable environment. An overview is presented of the various phytoplankton defense strategies, and costs and benefits of phytoplankton defenses with a zooming in on grazer-induced colony formation. The trade-off between phytoplankton competitive abilities and defenses against grazing favor adaptive trait changes—rapid evolution and phenotypic plasticity—that have the potential to influence population and community dynamics, as exemplified by controlled chemostat experiments. An interspecific defense–growth trade-off could explain seasonal shifts in the species composition of an in situ phytoplankton community yielding defense and growth rate as key traits of the phytoplankton. The importance of grazing and protection against grazing in shaping the phytoplankton community structure should not be underestimated. The trade-offs between nutrient acquisition, remaining suspended, and grazing resistance generate the dynamic phytoplankton community composition.

Download Full-text

The improbability of animal phyla with few species

Paleobiology ◽

10.1017/s009483730000748x ◽

1983 ◽

Vol 9 (2) ◽

pp. 97-106 ◽

Cited By ~ 33

Author(s):

Richard R. Strathmann ◽

Montgomery Slatkin

Keyword(s):

Short Duration ◽

Alternative Model ◽

Death Process ◽

Birth And Death Process ◽

Monophyletic Clade ◽

Number Of Species ◽

Extinction Rates ◽

Animal Phyla ◽

Speciation Rates ◽

Initial Radiation

At present there are many animal phyla that contain only a few species. The existence of these small phyla can be used to test assumptions about speciation and extinction in multicellular animals.We first model the number of species in a monophyletic clade with a birth and death process that assumes rates of speciation and extinction are constant. If no new phyla have evolved since the Cambrian and speciation and extinction rates for minor phyla are similar to or greater than those estimated from fossils, then our model shows that the probabilities of minor phyla surviving to the present are small. Random variation in extinction and speciation rates does not improve the chances for persistence. If speciation rates exceed extinction rates at the initial radiation of the clade, but before the clade becomes large, speciation rates come to equal extinction rates and both are low, persistence from before the Ordovician up to the present becomes likely. These models show that if speciation and extinction rates are independent of the number of species in a clade, then conditions before the Ordovician strongly influence today's distribution of species among taxa.We also discuss a model in which speciation and extinction rates depend on the number of species in a clade. This alternative model can account for the persistence of phyla with few species to the present and predicts a short duration for phyla that did not exceed a threshold number of species.

Download Full-text

Study and Design of an Ultrasonic Flow Tomographic Front-End Multi Level Measurement System

Jurnal Teknologi ◽

10.11113/jt.v69.3294 ◽

2014 ◽

Vol 69 (8) ◽

Author(s):

Goh Chiew Loon ◽

Ruzairi Abdul Rahim ◽

Suzanna Ridzuan Aw ◽

Fazlul Rahman Mohd Yunus ◽

Nor Muzakkir Nor Ayob ◽

...

Keyword(s):

Ultrasonic Transducer ◽

Rapid Evolution ◽

Flow Visualisation ◽

Ultrasonic Tomography ◽

Basic Operation ◽

Measurement Capability ◽

Front End ◽

Trade Offs ◽

Multi Level ◽

Primary Focus

With the rapid evolution of electro-acoustical technology, ultrasonic tomography has made considerable progress in industry. An ultrasonic tomography system provides non-invasive and non-intrusive flow visualisation that enhances the understanding of fluid flow processes. The function of ultrasonic tomography is to continuously monitor the dynamics of liquid flow without interrupting the flow. The ultrasonic tomography technique is fully supported by a front-end hardware system. The front end is defined as all the hardware circuitries, including the ultrasonic transducer up to the Analogue-to-Digital Convertors (ADCs), even though the primary focus is the analogue signal processing components. We present here the challenges and trade-offs in the implementation of a front-end system by first explaining the basic operation of such a system, and then indicating what particular performance parameters are needed to ensure optimal system operation. Based on the results from our research studies, we propose an improved front-end multi-level solution that is more accurate than previous solutions and provides real-time measurement capability.

Download Full-text