scholarly journals Impacts of experimental defoliation on native and invasive saplings: are native species more resilient to canopy disturbance?

2020 ◽  
Vol 40 (7) ◽  
pp. 969-979
Author(s):  
Elise D Hinman ◽  
Jason D Fridley
Keyword(s):  
Invasive Species ◽  
North America ◽  
Native Species ◽  
Radial Growth ◽  
Survival Rates ◽  
Growth Strategy ◽  
Extreme Weather Events ◽  
Leaf Production ◽  
Growing Seasons ◽  
Light Gradient

Abstract Many non-native, invasive woody species in mesic forests of North America are both shade tolerant and more productive than their native counterparts, but their ability to tolerate disturbances remains unclear. In particular, complete defoliation associated with herbivory and extreme weather events may have larger impacts on invaders if natives maintain greater resource reserves to support regrowth. On the other hand, invaders may be more resilient to partial defoliation by means of upregulation of photosynthesis or may be better able to take advantage of canopy gaps to support refoliation. Across a light gradient, we measured radial growth, new leaf production, non-structural carbohydrates (NSCs), chlorophyll content and survival in response to varying levels of defoliation in saplings of two native and two invasive species that commonly co-occur in deciduous forests of Eastern North America. Individuals were subjected to one of the four leaf removal treatments: no-defoliation controls, 50% defoliation over three growing seasons, 100% defoliation over one growing season and 100% defoliation over two growing seasons. Contrary to our hypothesis, native and invasive species generally did not differ in defoliation responses, although invasive species experienced more pronounced decreases in leaf chlorophyll following full defoliation and native species’ survival was more dependent on light availability. Radial growth progressively decreased with increasing defoliation intensity, and refoliation mass was largely a function of sapling size. Survival rates for half-defoliated saplings did not differ from controls (90% of saplings survived), but survival rates in fully defoliated individuals over one and two growing seasons were reduced to 45 and 15%, respectively. Surviving defoliated saplings generally maintained control NSC concentrations. Under high light, chlorophyll concentrations were higher in half-defoliated saplings compared with controls, which may suggest photosynthetic upregulation. Our results indicate that native and invasive species respond similarly to defoliation, despite the generally faster growth strategy of invaders.

scholarly journals First estimates of survival and densities of invasive alien Eastern cottontail (Sylvilagus floridanus) in Italy: a capture-recapture approach

2019 ◽  
Author(s):  
Jacopo Cerri ◽  
Sandro Bertolino
Keyword(s):  
North America ◽  
Native Species ◽  
Survival Rates ◽  
Northern Italy ◽  
High Survival ◽  
Sylvilagus Floridanus ◽  
Open Population ◽  
Capture Recapture ◽  
Eastern Cottontail ◽  
Selection Of

The Eastern cottontail (Sylvilagus floridanus) has become invasive in Central and Northern Italy, where it affects prey-predator dynamics between native species. Although many different studies explored survival rates and the density of cottontails in North America, no information is available for its invasive range. Between December 2003 and October 2005, a capture-recapture scheme for Eastern cottontails was enforced on the Orba River, Italy. We fitted an open-population Cormack-Jolly-Seber model to estimate survival of adult individuals (n=258) and their density in the study area. Adult cottontails showed a constant survival (phi = 0.84 ± 0.02) across the various sessions, as well as between individuals of different sexes. Capture probabilities and densities varied seasonally, with densities ranging between 2.06 ± 1.24 and 8.00 ± 4.60 cottontails/hectare, with an average of 4.72 individuals/hectare.Eastern cottontails are characterized by high survival and high densities, in their invaded range in Italy. Although densities are comparable to those reported in North America, our analysis focused on adult cottontails only and overall densities are certainly higher. Moreover, our estimates, obtained through a capture-recapture approach, were higher than those reported in previous studies from Italy that adopted nocturnal spotlight censuses. Spotlight transects are likely to underestimate cottontail densities, due to nocturnal habitat selection of cottontails, which might decrease their detectability.

scholarly journals Managing invasive species

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1686 ◽  
Author(s):  
Patrick C Tobin
Keyword(s):  
Invasive Species ◽  
North America ◽  
Native Species ◽  
Native Plants ◽  
Food Crops ◽  
Invasive Species Management ◽  
Scientific Communities ◽  
The World ◽  
Species Management ◽  
Private Citizens

Invasive species pose considerable harm to native ecosystems and biodiversity and frustrate and at times fascinate the invasive species management and scientific communities. Of the numerous non-native species established around the world, only a minority of them are invasive and noxious, whereas the majority are either benign or in fact beneficial. Agriculture in North America, for example, would look dramatically different if only native plants were grown as food crops and without the services of the European honey bee as a pollinator. Yet the minority of species that are invasive negatively alter ecosystems and reduce the services they provide, costing governments, industries, and private citizens billions of dollars annually. In this review, I briefly review the consequences of invasive species and the importance of remaining vigilant in the battle against them. I then focus on their management in an increasingly connected global community.

scholarly journals Effects of Climate Change on Invasive Species

2021 ◽  
pp. 57-83
Author(s):  
Deborah M. Finch ◽  
Jack L. Butler ◽  
Justin B. Runyon ◽  
Christopher J. Fettig ◽  
Francis F. Kilkenny ◽  
...  
Keyword(s):  
Climate Change ◽  
Invasive Species ◽  
Native Species ◽  
Summer Precipitation ◽  
The United States ◽  
Extreme Weather Events ◽  
Climate Projections ◽  
Geographic Ranges ◽  
Weather Events ◽  
Activity Temperature

AbstractMean surface temperatures have increased globally by ~0.7 °C per century since 1900 and 0.16 °C per decade since 1970 (Levinson and Fettig 2014). Most of this warming is believed to result from increases in atmospheric concentrations of greenhouse gases produced by human activity. Temperature increases have been greater in winter than in summer, and there is a tendency for these increases to be manifested mainly by changes in minimum (nighttime low) temperatures (Kukla and Karl 1993). Changes in precipitation patterns have also been observed, but are more variable than those of temperature. Even under conservative emission scenarios, future climatic changes are likely to include further increases in temperature with significant drying (drought) in some regions and increases in the frequency and severity of extreme weather events (IPCC 2007). For example, multimodel means of annual temperature from climate projections predict an increase of 3–9 °C in the United States over the next century combined with reductions in summer precipitation in certain areas (Walsh et al. 2014). These changes will affect invasive species in several ways. Furthermore, climate change may challenge the way we perceive and consider nonnative invasive species, as impacts to some will change and others will remain unaffected; other nonnative species are likely to become invasive; and native species are likely to shift their geographic ranges into novel habitats.

scholarly journals Documenting the occurrence through space & time of aquatic non-indigenous fish, mollusks, algae, & plants threatening North America's Great Lakes utilizing herbaria & zoological museum specimens

2018 ◽  
Vol 2 ◽  
pp. e24930
Author(s):  
Mark Wetter
Keyword(s):  
Invasive Species ◽  
North America ◽  
Great Lakes ◽  
Native Species ◽  
Zoological Museum ◽  
Indigenous Species ◽  
Accurate Identification ◽  
Space And Time ◽  
Non Indigenous Species ◽  
National Resource

North America’s Great Lakes contain 21% of the planet’s fresh water, and their protection is a matter of national security to both the USA & Canada. One of the greatest threats to the health of this unparalleled natural resource is invasion by non-indigenous species, several of which already have had catastrophic impacts on property values, the fisheries, shipping, and tourism industries, and continue to threaten the survival of native species and wetland ecosystems. The Great Lakes Invasives Network is a consortium (20 institutions) of herbaria and zoology museums from among the Great Lakes states of Minnesota, Wisconsin, Illinois, Indiana, Michigan, Ohio, and New York created to better document the occurrence of selected non-indigenous species and their congeners in space and time by imaging and providing online access to the information on the specimens of the critical organisms. The list of non-indigenous species (1 alga, 42 vascular plants, 22 fish, and 13 mollusks) to be digitized was generated by conducting a query of all fish, plants, algae, and mollusks present in the database of GLANSIS – the Great Lakes Aquatic Nonindigenous Species Information System – maintained by the National Oceanic and Atmospheric Administration (NOAA). The network consists of collections at 20 institutions, including 4 of the 10 largest herbaria in North America, each of which curates 1-7 million specimens (NY, F, MICH, and WIS). Eight of the nation’s largest zoology museums are also represented, several of which (e.g., Ohio State and U of Minnesota) are internationally recognized for their fish and mollusk collections. Each genus includes at least one species that is considered a Great Lakes non-indigenous taxon – several have many, whereas others have congeners on “watchlists”, meaning that they have not arrived in the Great Lakes Basin yet, but have the potential to do so, especially in light of human activity and climate change. Because the introduction and spread of these species, their close relatives, and hybrids into the region is known to have occurred almost entirely from areas in North America outside of the Basin, our effort will include non-indigenous specimens collected from throughout North America. Digitized specimens of Great Lakes non-indigenous species and their congeners will allow for more accurate identification of invasive species and hybrids from their non-invasive relatives by a wider audience of end users. The metadata derived from digitized specimens of Great Lakes non-indigenous species and their congeners will help biologists to track, monitor, and predict the spread of invasive species through space and time, especially in the face of a more rapidly changing climate in the upper Midwest. All together consortium members will digitize >2 million individual specimens from >860,000 sheets/lots of non-indigenous species and their congeneric taxa. Data and metadata are uploaded to the Great Lakes Invasives Network, a Symbiota portal (GreatLakesInvasvies.org), and ingested by the National Resource for Advancing Digitization of Biodiversity Collections (ADBC) (iDigBio.org) national resource. Several initiatives are already in place to alert citizens to the dangers of spreading aquatic invasive species among our nation's waterways, but this project is developing complementary scientific and educational tools for scientists, students, wildlife officers, teachers, and the public who have had little access to images or data derived directly from preserved specimens of invasive species collected over the past three centuries.

scholarly journals First estimates of survival and densities of invasive alien Eastern cottontail (Sylvilagus floridanus) in Italy: a Bayesian robust design approach

2020 ◽  
Author(s):  
Jacopo Cerri ◽  
Laura Gola ◽  
Aurelio Perrone ◽  
Sandro Bertolino
Keyword(s):  
North America ◽  
Robust Design ◽  
Native Species ◽  
Survival Rates ◽  
High Survival ◽  
Sylvilagus Floridanus ◽  
Capture Recapture ◽  
Males And Females ◽  
Eastern Cottontail ◽  
Selection Of

The Eastern cottontail (Sylvilagus floridanus) has become invasive in Central and Northern Italy, where it affects prey-predator dynamics between native species. Although many different studies explored survival rates and the density of cottontails in North America, no information is available for its invasive range. Between December 2003 and October 2005, a capture-recapture scheme for Eastern cottontails was enforced on the Orba River, Italy. We fitted a Bayesian version of the Pollock’s Closed Robust Design to estimate the survival of adult male and female cottontails (n=258) and their density in the study area. Adult cottontails showed minor seasonal differences in survival, with no clear differences between males and females. Densities varied seasonally, with females having higher densities (min = 80 individuals/km2; max = 553 individuals/km2) than males (min = 56 individuals/km2; max = 337 individuals/km2).Eastern cottontails are characterized by high survival and high densities, at least when adults, in their invaded range in Italy. Although densities are comparable to those reported in North America, our analysis focused on adult cottontails only and overall densities are certainly higher. Moreover, our estimates, obtained through a capture-recapture approach, were higher than those reported in previous studies from Italy based on nocturnal spotlight censuses. Spotlight transects are likely to underestimate cottontail densities, due to nocturnal habitat selection of cottontails, which might decrease their detectability.

High predatory efficiency and abundance drive expected ecological impacts of a marine invasive fish

2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Ecological Impact ◽  
Marine Species ◽  
Ecological Impacts ◽  
Negative Effects ◽  
Marine Predator ◽  
Eastern Gulf Of Mexico ◽  
Red Grouper ◽  
Per Capita

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.

scholarly journals Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 71
Author(s):  
Charalampos Dimitriadis ◽  
Ivoni Fournari-Konstantinidou ◽  
Laurent Sourbès ◽  
Drosos Koutsoubas ◽  
Stelios Katsanevakis
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
High Performance ◽  
Marine Protected Area ◽  
Habitat Degradation ◽  
Population Increase ◽  
Rocky Reef ◽  
Cascading Effects ◽  
High Level

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.

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