scholarly journals Testing Darwin’s naturalization conundrum based on taxonomic, phylogenetic and functional dimensions of vascular plants

2019 ◽  
Author(s):  
Jesús N. Pinto-Ledezma ◽  
Fabricio Villalobos ◽  
Peter B. Reich ◽  
Daniel J. Larkin ◽  
Jeannine Cavender-Bares
Keyword(s):  
Native Species ◽  
Charles Darwin ◽  
Environmental Gradients ◽  
Fire Frequency ◽  
Nonnative Species ◽  
Phylogenetic Structure ◽  
Spatial And Temporal Scales ◽  
Alternative Hypotheses ◽  
External Forces ◽  
Over Time

AbstractCharles Darwin posited two alternative hypotheses to explain the success of nonnative species based on their relatedness to incumbent natives: coexistence between them should be (i) more likely with greater relatedness (due to trait similarity that correlates with better matching to the environment), or (ii) less likely (due to biotic interference, such as competition). The paradox raised by the opposing predictions of these two hypotheses has been termed ‘Darwin’s naturalization conundrum’ (DNC). Using plant communities measured repeatedly over a 31-year time span across an experimental fire gradient in an oak savanna (Minnesota, USA) we evaluated the DNC by explicitly incorporating taxonomic, functional and phylogenetic information. Our approach was based on ‘focal-species’ such that the taxonomic, functional and phylogenetic structure of species co-occurring with a given nonnative species in local communities was quantified. We found three main results: first, nonnatives colonizers tended to co-occur most with closely related incumbent natives in recipient communities, except in the extreme ends of the fire gradient (i.e., communities with no fire and those subjected to high fire frequencies); second, with increasing fire frequency, nonnative species were functionally more similar to native species in recipient communities; third, functional similarity of co-occurring nonnatives and natives in recipient communities showed a consistent pattern over time, but the phylogenetic similarity shifted over time, suggesting that external forces (e.g., climate variability) are also relevant in driving the phylogenetic relatedness of nonnatives to natives in invaded communities. Our results provide insights for understanding the invasion dynamics across environmental gradients and highlight the importance of evaluating different dimensions of biodiversity in order to produce more powerful evaluations of species co-occurrence at different spatial and temporal scales.

Black Bass Diversity: Multidisciplinary Science for Conservation

2015 ◽  
Keyword(s):  
South Carolina ◽  
Native Species ◽  
Smallmouth Bass ◽  
Hybrid Origin ◽  
Nonnative Species ◽  
Savannah River ◽  
Conservation Actions ◽  
Precipitous Decline ◽  
Conservation Concern ◽  
Over Time

<em>Abstract</em>.—Bartram’s Bass (an as yet unnamed species similar to Redeye Bass <em>Micropterus coosae</em>) is endemic to the Savannah drainage of South Carolina and Georgia. Hybridization between this native species and introduced Alabama Bass <em>M. henshalli </em>is widespread in the upper portions of the drainage. Recent studies have documented a precipitous decline in genetically pure Bartram’s Bass in Savannah drainage reservoirs and a corresponding increase in fish of hybrid origin. We surveyed tributary populations associated with these reservoirs and with the Savannah River main stem in 2004 and 2010. Results indicate an increased occurrence of hybrids in Bartram’s Bass native stream habitats over time. We also document the new occurrence of a second nonnative species, Smallmouth Bass <em>M. dolomieu</em>. Both Smallmouth Bass and their hybrids with Bartram’s Bass were collected from shoals in the Savannah River near the lower extent of the Bartram’s Bass range. Bartram’s Bass is a species of highest conservation concern in South Carolina, due to its limited native range and threats associated with hybridization. Conservation actions directed at this species, and its native stream habitats, will need to consider the establishment of nonnative species in the drainage and their potential to impact tributary populations over time.

scholarly journals The Urban River Syndrome: Achieving Sustainability Against a Backdrop of Accelerating Change

2021 ◽  
Vol 18 (12) ◽  
pp. 6406
Author(s):  
Martin Richardson ◽  
Mikhail Soloviev
Keyword(s):  
River Restoration ◽  
Native Species ◽  
Systems Approach ◽  
Similar Type ◽  
Urban River ◽  
Urban Rivers ◽  
River Ecology ◽  
Spatial And Temporal Scales ◽  
Natural Systems ◽  
Urban River Restoration

Human activities have been affecting rivers and other natural systems for millennia. Anthropogenic changes to rivers over the last few centuries led to the accelerating state of decline of coastal and estuarine regions globally. Urban rivers are parts of larger catchment ecosystems, which in turn form parts of wider nested, interconnected systems. Accurate modelling of urban rivers may not be possible because of the complex multisystem interactions operating concurrently and over different spatial and temporal scales. This paper overviews urban river syndrome, the accelerating deterioration of urban river ecology, and outlines growing conservation challenges of river restoration projects. This paper also reviews the river Thames, which is a typical urban river that suffers from growing anthropogenic effects and thus represents all urban rivers of similar type. A particular emphasis is made on ecosystem adaptation, widespread extinctions and the proliferation of non-native species in the urban Thames. This research emphasizes the need for a holistic systems approach to urban river restoration.

scholarly journals Historical patterns of wildfire ignition sources in California ecosystems

2018 ◽  
Vol 27 (12) ◽  
pp. 781 ◽  
Author(s):  
Jon E. Keeley ◽  
Alexandra D. Syphard
Keyword(s):  
Fire Hazard ◽  
Fire Frequency ◽  
Federal Agencies ◽  
The State ◽  
United States Forest Service ◽  
The Past ◽  
Design Fire ◽  
Fire Ignition ◽  
Over Time ◽  
Marked Drop

State and federal agencies have reported fire causes since the early 1900s, explicitly for the purpose of helping land managers design fire-prevention programs. We document fire-ignition patterns in five homogenous climate divisions in California over the past 98 years on state Cal Fire protected lands and 107 years on federal United States Forest Service lands. Throughout the state, fire frequency increased steadily until a peak c. 1980, followed by a marked drop to 2016. There was not a tight link between frequency of ignition sources and area burned by those sources and the relationships have changed over time. Natural lightning-ignited fires were consistently fewer from north to south and from high to low elevation. Throughout most of the state, human-caused fires dominated the record and were positively correlated with population density for the first two-thirds of the record, but this relationship reversed in recent decades. We propose a mechanistic multi-variate model of factors driving fire frequency, where the importance of different factors has changed over time. Although ignition sources have declined markedly in recent decades, one notable exception is powerline ignitions. One important avenue for future fire-hazard reduction will be consideration of solutions to reduce this source of dangerous fires.

scholarly journals Dispersão de Espécie Exótica no Parque Nacional da Lagoa do Peixe e Seu Entorno (Dispersion of Exotic Vegetation Into and Around the Lagoa do Peixe National Park)

2011 ◽  
Vol 4 (1) ◽  
pp. 33 ◽  
Author(s):  
Luana Portz ◽  
Rogério Portantiollo Manzolli ◽  
Dejanira Luderitz Saldanha ◽  
Iran Carlos Stalliviere Correa
Keyword(s):  
Native Species ◽  
National Park ◽  
Rio Grande ◽  
Multispectral Images ◽  
Rio Grande Do Sul ◽  
Field Verification ◽  
Exotic Vegetation ◽  
Manual Classification ◽  
Natural Dispersal ◽  
Over Time

O Parque Nacional da Lagoa do Peixe está localizado no litoral sul do estado do Rio Grande do Sul. Dentre os conflitos existentes dentro da área do parque e no seu entorno, o aumento e a dispersão da vegetação exótica, vem gerando inúmeras discussões. Neste contexto o objetivo do presente trabalho foi identificar a distribuição espacial, ao longo do tempo, das áreas de plantações de Pinus sp. Para tanto foram utilizadas imagens multiespectrais de sensoriamento remoto (TM-Landsat 5), com datas entre 1986 e 2009, sendo realizada a classificação manual por meio da vetorização, verificação de campo e análise quantitativa e qualitativa dos resultados obtidos. O problema principal da dispersão natural de Pinus sp. é encontrado na margem da lagoa principal, margeada por banhados e por pinus, cuja dispersão espontânea está competindo com o crescimento da vegetação natural e alterando o cenário típico da região. De 1986, data de criação do parque, até hoje a área de pinus, no entorno desta lagoa, cresceu de 61 para 252 ha. Este aumento da área de ocorrência de Pinus sp, em mais de 4 vezes, torna necessária a sua extração, a fim de preservar as espécies nativas da região, bem como a diversidade biológica a ela associada. A expansão da silvicultura é preocupante, pois assumiu uma grande proporção em área, não se encontrando ações que indiquem uma desaceleração deste processo. Além de diminuir o valor estético da paisagem natural esta invasão poderá comprometer o potencial turístico e principalmente de preservação ambiental ao qual o título de Parque Nacional exige.Palavras chaves: Pinus sp., Landsat, impactos. Dispersion of Exotic Vegetation Into and Around the Lagoa do Peixe National Park  ABSTRACTLagoa do Peixe National Park presents a great variety of fragile ecosystems. Among the conflicts present into and around the Park is the increase and dispersion of exotic vegetation, that is generating several discussions. In this context, the objective of this paper was identifying the spatial distribution, over time, of the Pinus sp. plantations in this area. For both researches, it was used multispectral images (Landsat), with dates between 1986 and 2009, and performed the manual classification, field verification and analysis of quantitative and qualitative results. The main problem related to the natural dispersal of Pinus sp. is found on the shore of the park’s main lagoon. This area is bordered by marshes and Pinus sp. whose spontaneous dispersion is competing with the natural vegetation and altering the typical scenery of this region. Since the creation of the park (1986) until today, the area of pinus, around the lagoon, has grown from 61 to 252 ha. This increase, more than four times, makes it necessary its extraction in order to preserve the native species and the biodiversity associated. The expansion of forestry in the Lagoa do Peixe National Park is worrisome because it has been taking a great extent of the area, and there are no actions that indicate a slowdown of this process.Keyword: Pinus sp., Landsat, impact.

scholarly journals Decline in New Zealand's freshwater fish fauna: Effect of land use

2020 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria
Keyword(s):  
New Zealand ◽  
Land Cover ◽  
Freshwater Fish ◽  
Native Species ◽  
Species Abundance ◽  
Fish Fauna ◽  
Fish Distribution ◽  
Individual Species ◽  
Freshwater Fish Fauna ◽  
Over Time

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.

Scaling Issues in Landscape Ecology

2019 ◽  
pp. 14-41
Author(s):  
Kimberly A. With
Keyword(s):  
Landscape Ecology ◽  
Spatial Patterns ◽  
Spatial Scales ◽  
Ecological Data ◽  
Ecological Forecasting ◽  
Spatial And Temporal Scales ◽  
Time Periods ◽  
Patterns And Processes ◽  
Short Time ◽  
Over Time

Spatial patterns are ubiquitous in nature, and ecological systems exhibit patchiness (heterogeneity) across a range of spatial and temporal scales. Landscape ecology is explicitly concerned with understanding how scale affects the measurement of heterogeneity and the scale(s) at which spatial pattern is important for ecological phenomena. Patterns and processes measured at fine spatial scales and over short time periods are unlikely to behave similarly at broader scales and extended time periods. An understanding of pattern-process linkages, a major research focus in landscape ecology, thus requires an understanding of how patterns change with scale, spatially and temporally. The development of methods for extrapolating information across scales is necessary for predicting how landscapes will change over time as well as for ecological forecasting. This chapter explores how scaling issues affect ecological investigations, discusses problems in identifying the correct scale for research, and outlines when and how ecological data can be extrapolated.

Scale dependence in the phylogenetic relatedness of alien and native taxa

2020 ◽  
Vol 13 (5) ◽  
pp. 601-610
Author(s):  
Chris M McGrannachan ◽  
Gillis J Horner ◽  
Melodie A McGeoch
Keyword(s):  
Alien Species ◽  
Spatial Scale ◽  
Native Species ◽  
Spatial Scales ◽  
Pairwise Distance ◽  
Phylogenetic Structure ◽  
Phylogenetic Clustering ◽  
Phylogenetic Relatedness ◽  
Darwin's Naturalization Hypothesis ◽  
Darwin’S Naturalization Hypothesis

Abstract Aims Darwin’s naturalization hypothesis proposes that successfully established alien species are less closely related to native species due to differences in their ecological niches. Studies have provided support both for and against this hypothesis. One reason for this is the tendency for phylogenetic clustering between aliens and natives at broad spatial scales with overdispersion at fine scales. However, little is known about how the phylogenetic relatedness of alien species alters the phylogenetic structure of the communities they invade, and at which spatial scales effects may manifest. Here, we examine if invaded understorey plant communities, i.e. containing both native and alien taxa, are phylogenetically clustered or overdispersed, how relatedness changes with spatial scale and how aliens affect phylogenetic patterns in understorey communities. Methods Field surveys were conducted in dry forest understorey communities in south-east Australia at five spatial scales (1, 20, 500, 1500 and 4500 m2). Standardized effect sizes of two metrics were used to quantify phylogenetic relatedness between communities and their alien and native subcommunities, and to examine how phylogenetic patterns change with spatial scale: (i) mean pairwise distance and (ii) mean nearest taxon distance (MNTD). Important Findings Aliens were closely related to each other, and this relatedness tended to increase with scale. Native species and the full community exhibited either no clear pattern of relatedness with increasing spatial scale or were no different from random. At intermediate spatial scales (20–500 m2), the whole community tended towards random whereas the natives were strongly overdispersed and the alien subcommunity strongly clustered. This suggests that invasion by closely related aliens shifts community phylogenetic structure from overdispersed towards random. Aliens and natives were distantly related across spatial scales, supporting Darwin’s naturalization hypothesis, but only when phylogenetic distance was quantified as MNTD. Phylogenetic dissimilarity between aliens and natives increased with spatial scale, counter to expected patterns. Our findings suggest that the strong phylogenetic clustering of aliens is driven by human-mediated introductions involving closely related taxa that can establish and spread successfully. Unexpected scale-dependent patterns of phylogenetic relatedness may result from stochastic processes such as fire and dispersal events and suggest that competition and habitat filtering do not exclusively dominate phylogenetic relationships at fine and coarse spatial scales, respectively. Distinguishing between metrics that focus on different evolutionary depths is important, as different metrics can exhibit different scale-dependent patterns.

scholarly journals Ichthyological Differentiation and Homogenization in the Pánuco Basin, Mexico

Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 187 ◽  
Author(s):  
Norma Martínez-Lendech ◽  
Ana P. Martínez-Falcón ◽  
Juan Jacobo Schmitter-Soto ◽  
Humberto Mejía-Mojica ◽  
Valentino Sorani-Dalbón ◽  
...  
Keyword(s):  
Species Composition ◽  
Native Species ◽  
Ecosystem Change ◽  
Species Introductions ◽  
Fish Collection ◽  
Species Groups ◽  
Conservation Concern ◽  
Key Aspects ◽  
Independent Species ◽  
Over Time

Species introductions and extirpations are key aspects of aquatic ecosystem change that need to be examined at large geographic and temporal scales. The Pánuco Basin (Eastern Mexico) has high ichthyological diversity and ecological heterogeneity. However, freshwater fish (FWF) introductions and extirpations since the mid-1900s have modified species range and distribution. We examine changes in FWF species composition in and among four sub-basins of the Pánuco by comparing fish collection records pre-1980 to 2018. Currently, the FWF of the Pánuco includes 95 species. Fishes in the Poeciliidae, Cyprinidae, and Cichlidae, respectively, comprised most records over time. Significant differences in species composition were found between the first (pre-1980) and last (2011–2018) study periods, but not for periods in-between. Eight independent species groups were key for explaining changes in Pánuco river ichthyofauna; one group was dominated by invasive species, and saw increases in the number of records across study periods (faunal homogenization). Another group was formed by species with conservation concern with a declining number of records over time. Thirteen (2 native and 11 non-native) species were responsible for temporal turnover. These results strongly suggest high rates of differentiation over time (via native species loss) following widespread non-native species introductions.

scholarly journals Niche Models Differentiate Potential Impacts of Two Aquatic Invasive Plant Species on Native Macrophytes

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 162
Author(s):  
Michael R. Verhoeven ◽  
Wesley J. Glisson ◽  
Daniel J. Larkin
Keyword(s):  
Native Species ◽  
Invasive Plant ◽  
Environmental Gradients ◽  
Myriophyllum Spicatum ◽  
Light Availability ◽  
Niche Overlap ◽  
Growth Cycle ◽  
Potamogeton Crispus ◽  
Starting Point ◽  
Niche Models

Potamogeton crispus (curlyleaf pondweed) and Myriophyllum spicatum (Eurasian watermilfoil) are widely thought to competitively displace native macrophytes in North America. However, their perceived competitive superiority has not been comprehensively evaluated. Coexistence theory suggests that invader displacement of native species through competitive exclusion is most likely where high niche overlap results in competition for limiting resources. Thus, evaluation of niche similarity can serve as a starting point for predicting the likelihood of invaders having direct competitive impacts on resident species. Across two environmental gradients structuring macrophyte communities—water depth and light availability—both P. crispus and M. spicatum are thought to occupy broad niches. For a third dimension, phenology, the annual growth cycle of M. spicatum is typical of other species, whereas the winter-ephemeral phenology of P. crispus may impart greater niche differentiation and thus lower risk of native species being competitively excluded. Using an unprecedented dataset comprising 3404 plant surveys from Minnesota collected using a common protocol, we modeled niches of 34 species using a probabilistic niche framework. Across each niche dimension, P. crispus had lower overlap with native species than did M. spicatum; this was driven in particular by its distinct phenology. These results suggest that patterns of dominance seen in P. crispus and M. spicatum have likely arisen through different mechanisms, and that direct competition with native species is less likely for P. crispus than M. spicatum. This research highlights the utility of fine-scale, abundance-based niche models for predicting invader impacts.

Do water quality criteria based on nonnative species provide appropriate protection for native species?

2015 ◽  
Vol 34 (8) ◽  
pp. 1793-1798 ◽  
Author(s):  
Xiaowei Jin ◽  
Zijian Wang ◽  
Yeyao Wang ◽  
Yibing Lv ◽  
Kaifeng Rao ◽  
...  
Keyword(s):  
Water Quality ◽  
Native Species ◽  
Quality Criteria ◽  
Nonnative Species ◽  
Water Quality Criteria
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