Manipulation of density of Pseudotsuga menziesii canopies: preliminary effects on understory vegetation

2001 ◽  
Vol 31 (9) ◽  
pp. 1513-1525 ◽  
Author(s):  
David R Thysell ◽  
Andrew B Carey
Keyword(s):  
Exotic Species ◽  
Pseudotsuga Menziesii ◽  
Native Species ◽  
Variable Density ◽  
Unintended Consequences ◽  
Managed Forest ◽  
Forest Canopies ◽  
Dead Trees ◽  
Second Growth ◽  
Closed Canopy

Managing second-growth forests to conserve biodiversity has been proposed by both foresters and conservation biologists. Management, however, can have unintended consequences, including reduction in native species diversity and increased invasion by exotic species. Our goal was to determine if inducing heterogeneity in managed forest canopies could promote a diversity of native species without contributing markedly to invasion by exotic species. We examined 1- and 3-year responses of understory plants to variable-density thinning of 55- to 65-year-old stands of Pseudotsuga menziesii (Mirb.) Franco. Our study stands had been managed either with retention of old-growth legacies (large live trees, dead trees, and fallen trees) and no thinning or with removal of legacies and twice-repeated conventional thinning. Variable-density thinning initially resulted in decreased understory cover but increased importance of 20 native species, including 2 species of trees. Two native species, however, decreased in importance, and 11 exotic species increased in importance. Within 3 years, understory cover recovered, species richness increased by >150%, only four exotic species persisted with increased importance, eight native species (including four graminoids) increased in importance, and seven native species decreased in importance. Variable-density thinning shows promise as part of holistic silvicultural systems applied across landscapes throughout stand rotations and as a technique to restore vegetative complexity to closed-canopy second-growth forests.

Land-use change on Mount Gede, Indonesia, reduced native earthworm populations and diversity

2017 ◽  
Vol 65 (4) ◽  
pp. 217 ◽  
Author(s):  
Andy Darmawan ◽  
Tri Atmowidi ◽  
Wasmen Manalu ◽  
Bambang Suryobroto
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Native Species ◽  
Crop Production ◽  
Diversity Index ◽  
Agroforestry Systems ◽  
Tree Cover ◽  
Managed Forest ◽  
Earthworm Species ◽  
Mixed Plantation

The conversion of natural forest to agroforestry plantations and annual cropping systems alters the soil habitat and food resources for biota, including earthworms. Native earthworm species may disappear whereas exotic species with greater tolerance of disturbance and less niche specialisation may thrive. The objective of the study was to compare the earthworm diversity in managed forest and agroforestry systems, which were cultivated for mixed plantation and annual crop production on Mount Gede, Indonesia. All the habitats in the study area were impacted by humans. The forest habitat was a managed forest, with a permanent tree cover, whereas mixed plantation had a partial shrub cover. Meanwhile, homogenous plantation was cultivated with annual crops. Among 3787 individuals collected during July–October 2012, five Oriental earthworm species were identified in the soil communities of Mount Gede: Drawida nepalensis, Notoscolex javanica, Pheretima pura-group, Polypheretima moelleri, and Polypheretima sempolensis. Also, 18 species were found that are reported to be non-Oriental in origin. Anthropogenic disturbance of forests on Mount Gede, due to conversion into plantations, alters the earthworm environment by increasing soil water content, temperature and total phosphorous content, while decreasing organic carbon. N. javanica was the only native species to survive this deforestation, while the exotic Ocnerodrilus occidentalis and Pontoscolex corethrurus thrived, becoming the eudominant species. From the forest area to the mixed and homogenous plantations, the predicted decreasing diversity is evidenced by the lowering trend of Shannon’s diversity index. In conclusion, the land-use change into mixed plantations and annual croplands has reduced earthworm diversity in this region of Mount Gede, Indonesia.

scholarly journals Alien Species vs. Native Species: From Community Ecology to Eco-Evolutionary Dynamics

2019 ◽  
Author(s):  
Andersonn Silveira Prestes
Keyword(s):  
Alien Species ◽  
Exotic Species ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Evolutionary Processes ◽  
Native Communities ◽  
Individualized Approach ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

The establishment and spread of exotic species is a contemporary major concern. Alien species may become invasive in their new habitat, leading to both/either environmental and/or economic impacts. I briefly reviewed the literature in the last decade about the relationship of exotic species and native communities. I identified that professionals usually approach the subject in two main points of view: (1) researchers tend to point out the impacts of alien species on entire communities, evaluating if the relationship is positive, negative or neutral; (2) they focus on the eco-evolutionary processes involved in the introductions, the dynamics of invasion, and individual study cases. When evaluating the response of introductions to entire communities, evidence seems to be ambiguous and may support positive, negative or neutral relationship, especially depending on the scale approached. The unique eco-evolutionary pathways of each introduction may be a great shortcoming in the searching for generalities. On the other hand, advances have been made in understanding the dynamics of invasion on different lineages through a more selective/individualized approach. I suggest that the dynamics of invasion might be studied through a perspective in which different eco-evolutionary processes, levels of organization (from gene to entire communities), the history of the organism(s) and time are taken into account. Individual cases might be compared in attempt to understand how the relationship exotic and native works and in the search for generalities.

scholarly journals Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community

2020 ◽  
Vol 11 (1) ◽  
pp. 164-173
Author(s):  
Julia S.M. Ersan ◽  
Brian J. Halstead ◽  
Erica L. Wildy ◽  
Michael L. Casazza ◽  
Glenn D. Wylie
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Prey Selection ◽  
Central Valley ◽  
Prey Preference ◽  
Live Prey ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Behavioral Trials ◽  
Selection Of

Abstract The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas, an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

Effect of indaziflam on native species in natural areas and rangeland

2019 ◽  
Vol 12 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Shannon L. Clark ◽  
Derek J. Sebastian ◽  
Scott J. Nissen ◽  
James R. Sebastian
Keyword(s):  
Species Richness ◽  
Weed Management ◽  
Native Species ◽  
Species Abundance ◽  
Unintended Consequences ◽  
Ecological Impacts ◽  
Limited Information ◽  
Perennial Species ◽  
Temporary Reduction ◽  
Species Richness And Abundance

AbstractMinimizing the negative ecological impacts of exotic plant invasions is one goal of land management. Using selective herbicides is one strategy to achieve this goal; however, the unintended consequences of this strategy are not always fully understood. The recently introduced herbicide indaziflam has a mode of action not previously used in non-crop weed management. Thus, there is limited information about the impacts of this active ingredient when applied alone or in combination with other non-crop herbicides. The objective of this research was to evaluate native species tolerance to indaziflam and imazapic applied alone and with other broadleaf herbicides. Replicated field plots were established at two locations in Colorado with a diverse mix of native forbs and grasses. Species richness and abundance were compared between the nontreated control plots and plots where indaziflam and imazapic were applied alone and in combination with picloram and aminocyclopyrachlor. Species richness and abundance did not decrease when indaziflam or imazapic were applied alone; however, species abundance was reduced by treatments containing picloram and aminocyclopyrachlor. Species richness was only impacted at one site 1 yr after treatment (YAT) by these broadleaf herbicides. Decreases in abundance were mainly due to reductions in forbs that resulted in a corresponding increase in grass cover. Our data suggest that indaziflam will control downy brome (Bromus tectorumL.) for multiple years without reduction in perennial species richness or abundance. IfB. tectorumis present with perennial broadleaf weeds requiring the addition of herbicides like picloram or aminocyclopyrachlor, forb abundance could be reduced, and in some cases there could be a temporary reduction in perennial species richness.

scholarly journals Forest Canopy Can Efficiently Filter Trace Metals in Deposited Precipitation in a Subalpine Spruce Plantation

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 318 ◽  
Author(s):  
Siyi Tan ◽  
Hairong Zhao ◽  
Wanqin Yang ◽  
Bo Tan ◽  
Kai Yue ◽  
...  
Keyword(s):  
Trace Metals ◽  
Human Disturbance ◽  
Forest Canopy ◽  
Subalpine Forest ◽  
Forest Canopies ◽  
Closed Canopy ◽  
Filtering Efficiency ◽  
One Year ◽  
The One ◽  
Filtering Effect

Trace metals can enter natural regions with low human disturbance through atmospheric circulation; however, little information is available regarding the filtering efficiency of trace metals by forest canopies. In this study, a representative subalpine spruce plantation was selected to investigate the net throughfall fluxes of eight trace metals (Fe, Mn, Cu, Zn, Al, Pb, Cd and Cr) under a closed canopy and gap-edge canopy from August 2015 to July 2016. Over the one-year observation, the annual fluxes of Al, Zn, Fe, Mn, Cu, Cd, Cr and Pb in the deposited precipitation were 7.29 kg·ha−1, 2.30 kg·ha−1, 7.02 kg·ha−1, 0.16 kg·ha−1, 0.19 kg·ha−1, 0.06 kg·ha−1, 0.56 kg·ha−1 and 0.24 kg·ha−1, respectively. The annual net throughfall fluxes of these trace metals were −1.73 kg·ha−1, −0.90 kg·ha−1, −1.68 kg·ha−1, 0.03 kg·ha−1, −0.03 kg·ha−1, −0.02 kg·ha−1, −0.09 kg·ha−1 and −0.08 kg·ha−1, respectively, under the gap-edge canopy and 1.59 kg·ha−1, −1.13 kg·ha−1, −1.65 kg·ha−1, 0.10 kg·ha−1, −0.04 kg·ha−1, −0.03 kg·ha−1, −0.26 kg·ha−1 and −0.15 kg·ha−1, respectively, under the closed canopy. The closed canopy displayed a greater filtering effect of the trace metals from precipitation than the gap-edge canopy in this subalpine forest. In the rainy season, the net filtering ratio of trace metals ranged from −66.01% to 89.05% for the closed canopy and from −52.32% to 33.09% for the gap-edge canopy. In contrast, the net filtering ratio of all trace metals exceeded 50.00% for the closed canopy in the snowy season. The results suggest that most of the trace metals moving through the forest canopy are filtered by canopy in the subalpine forest.

scholarly journals Nest Sites and Nest Webs for Cavity-Nesting Communities in Interior British Columbia, Canada: Nest Characteristics and Niche Partitioning

The Condor ◽  
2004 ◽  
Vol 106 (1) ◽  
pp. 5-19 ◽  
Author(s):  
Kathy Martin ◽  
Kathryn E. H. Aitken ◽  
Karen L. Wiebe
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Populus Tremuloides ◽  
Full Range ◽  
Sturnus Vulgaris ◽  
Mammal Species ◽  
Cavity Nesters ◽  
Cavity Nesting ◽  
Dead Trees ◽  
Colaptes Auratus

Abstract The mixed forests of interior British Columbia, Canada, support a rich community of cavity nesters, accounting for about one-third of forest vertebrate species. For 20 cavity-nesting bird and six cavity-nesting mammal species, representing excavators and secondary cavity nesters, we measured nest-cavity and nest-tree characteristics over 8 years in Interior Douglas-fir (Pseudotsuga menziesii) forest ecosystems. There was overwhelming selection for quaking aspen (Populus tremuloides); 95% of 1692 cavity nests were in aspen, which comprised only 15% of trees available. The full range of live and dead trees were used, but we observed a strong preference for live trees with decay (45% of nests) or dead trees (45% of nests). A cluster analysis based on tree and cavity characteristics divided the community into five groups, including large- and medium-sized woodpeckers and a group comprised mostly of weak excavators. A fourth group included Northern Flickers (Colaptes auratus), the most abundant excavator, and the larger secondary cavity nesters. The final group contained the most aggressive and most abundant secondary cavity nesters. European Starling (Sturnus vulgaris), the most aggressive secondary cavity nester, occupied a narrower nest niche (in less-decayed trees with smaller entrances) relative to their size. Less-competitive excavators and secondary cavity nesters occupied wider nest niches in terms of tree decay class and cavity size. We constructed a nest web for community structure that showed most cavity resource use flowed up the community through aspen trees and cavities excavated by Northern Flickers. Thus, aspen was the critical nesting tree and Northern Flickers were the keystone excavators in this community. Sitios de Nidificación y Redes de Nidos en Comunidades que Nidifican en Cavidades en el Interior de British Columbia, Canadá: Características de los Nidos y Separación de Nichos Resumen. Los bosques mixtos del interior de British Columbia, Canadá, albergan una rica comunidad de animales que nidifican en cavidades, los cuales representan aproximadamente un tercio de las especies de vertebrados de bosque. En este estudio medimos características de las cavidades y de los árboles de nidificación para 20 especies de aves y seis de mamíferos que nidifican en cavidades (incluyendo especies excavadoras y las que utilizan cavidades secundariamente) a lo largo de ocho años en ecosistemas de bosque interior de Pseudotsuga menziesii. Hubo una selección abrumadora de árboles de la especie Populus tremuloides; el 95% de 1692 cavidades de nidificación se encontraron en árboles de esta especie, la cual comprendía sólo el 15% de los árboles disponibles. Todo el espectro de árboles vivos y muertos fue utilizado, pero observamos una preferencia fuerte por árboles vivos con descomposición (45% de los nidos) o árboles muertos (45% de los nidos). Un análisis de agrupamiento basado en características de los árboles y las cavidades dividió la comunidad en cinco grupos, incluyendo carpinteros de tamaño grande y mediano, y un grupo formado principalmente por excavadores débiles. Un cuarto grupo incluyó al carpintero Colaptes auratus (el excavador más abundante) y a las especies de mayor tamaño que nidifican en cavidades secundarias. El último grupo incluyó a las especies más abundantes y agresivas que nidifican en cavidades secundarias. El estornino Sturnus vulgaris, la especie más agresiva que nidifica en cavidades secundarias, ocupó un nicho más estrecho (árboles menos descompuestos con entradas más pequeñas) con relación a su tamaño. Los excavadores menos competitivos y los usuarios de cavidades secundarias ocuparon nichos de nidificación más amplios en términos de la categoría de descomposición de los árboles y el tamaño de la cavidad. Construimos una red de nidos para estudiar la estructura de la comunidad, la cual mostró que la mayor parte del uso de las cavidades como recurso fluye en la comunidad a través de los árboles de P. tremuloides y las cavidades excavadas por C. auratus. Por lo tanto, P. tremuloides fue el árbol de nidificación crítico y C. auratus fue la especie de excavador clave en esta comunidad.

Invaders induce coordinated isotopic niche shifts in native fish species

2020 ◽  
Vol 77 (8) ◽  
pp. 1348-1358 ◽  
Author(s):  
Jane S. Rogosch ◽  
Julian D. Olden
Keyword(s):  
Food Web ◽  
Native Species ◽  
Fish Assemblages ◽  
Isotope Analysis ◽  
Carbon Sources ◽  
Unintended Consequences ◽  
Trophic Levels ◽  
Isotopic Niche ◽  
Mesopredator Release ◽  
Native Fishes

Food-web investigations inform management strategies by exposing potential interactions between native and nonnative species and anticipating likely outcomes associated with species removal efforts. We leveraged a natural gradient of compositional turnover from native-only to nonnative-only fish assemblages, combined with an intensive removal effort, to investigate underlying food-web changes in response to invasive species expansion in a Lower Colorado River tributary. Nonnative fishes caused coordinated isotopic niche displacement in native fishes by inducing resource shifts toward lower trophic positions and enriched carbon sources. By contrast, nonnative fishes did not experience reciprocal shifts when native fishes were present. Asymmetrical outcomes between native and nonnative fishes indicated species displacement may result from competitive or consumptive interactions. Native species’ isotopic niches returned to higher trophic levels after nonnative green sunfish (Lepomis cyanellus) removal, indicating removal efforts can support trophic recovery of native fishes like desert suckers (Catostomus clarkii) and roundtail chub (Gila robusta). Using stable isotope analysis in preremoval assessments provides opportunities to identify asymmetric interactions, whereas postremoval assessments could identify unintended consequences, like mesopredator release, as part of adaptive decision making to recover native fishes.

U.S. State's View and Regulations on Fish Introductions

1991 ◽  
Vol 48 (S1) ◽  
pp. 167-170 ◽  
Author(s):  
Paul J. Wingate
Keyword(s):  
Exotic Species ◽  
Fish Species ◽  
Native Species ◽  
Good Thing ◽  
Political Pressure ◽  
Fish Introductions ◽  
Genetic Strains

A survey of the poiicy of 50 U.S. states on transplanted fish introductions and stocking fish of different genetic strains indicates that all 39 responding states control exotic introductions. While 67% of the responding states restrict in-state movement of fish species, more attention is being given to restricting in-state strain movement. More needs to be done. Native species are stocked on top of reproducing populations and moved among watersheds; exotic species are introduced. In some cases, these stockings have appeared to benefit all interested parties, while in other circumstances exotics have totally disrupted ecosystems and become pests. These introductions and stockings are a combination of the fish being available, misunderstanding by managers of possible effects, and strong political pressure to satisfy anglers in more and more waters. Many times, little attention is given to the effect of these introductions on the native biota and fauna as it is perceived that stocking fish is a good thing. It is not until problems develop or anglers want another species added that the wisdom or success of these stockings is questioned. Minnesota's policy is that fish are not moved between watersheds until genetic similarities of the various species in the different watersheds are demonstrated.

The loss of native terrestrial small mammals in large urban reserves in the Australian Capital Territory

2010 ◽  
Vol 16 (1) ◽  
pp. 36 ◽  
Author(s):  
A. J. Buckmaster ◽  
W. S. Osborne ◽  
N. Webb
Keyword(s):  
Species Composition ◽  
Exotic Species ◽  
Native Species ◽  
Indirect Detection ◽  
Urban Landscapes ◽  
Australian Capital Territory ◽  
Mammal Species ◽  
Detection Techniques ◽  
Australian Capital ◽  
Terrestrial Mammals

Urban development can alter species composition and diversity within an area through biotic homogenization, the introduction of exotic species, and localized extinctions of native species. In this study we examined the composition and diversity of small terrestrial mammals within nature reserves surrounded by urban landscapes and compared this with previous surveys of these reserves and nearby non-urban reserves with similar vegetative and geomorphological characteristics. A combination of live trapping and indirect detection techniques was employed in eight reserves in the Australian Capital Territory and surrounding New South Wales to determine current species composition. Compared with previous studies and the non-urban reserves, the urban reserves appear to have lost two-thirds of their native terrestrial small mammal species in the past 26 years. Exotic species were present in all urban reserves, but were only associated with areas characterized by human-induced disturbance in non-urban reserves. Possible causes of this disparity in native species diversity between urban and non-urban reserves are discussed.

scholarly journals Native Seedling Colonization on Stockpiled Mine Soils Is Constrained by Site Conditions and Competition with Exotic Species

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 361 ◽  
Author(s):  
Kathy A. Baethke ◽  
Laura W. Ploughe ◽  
Wendy C. Gardner ◽  
Lauchlan H. Fraser
Keyword(s):  
Exotic Species ◽  
Seedling Establishment ◽  
Native Species ◽  
Seed Treatment ◽  
Native Vegetation ◽  
Mine Soils ◽  
Native Seed ◽  
Restoration Strategies ◽  
Arid Grasslands ◽  
Establishment Phase

Sites disturbed through mining practices can be challenging to restore with native vegetation, as the path of ecological succession is often unknown and hard to predict. We conducted an establishment study that explored restoration strategies to increase native vegetation on a newly formed stockpile of soil at New Gold’s New Afton Mine in British Columbia, Canada. Establishment of native species in semi-arid grasslands is often constrained by seed and seedling microsite limitations, so treatments were imposed to assist in reducing these limitations. We established a fully factorial design with a native seed treatment (seeded and unseeded) and four soil preparations: raking, hydroseed slurry, a combination of raking and hydroseed slurry, and no preparation. Raking assisted in increasing total seedling establishment, regardless of whether the site was seeded or not. Raking and seeding increased the number of native seedlings and resulted in the greatest species richness, suggesting that native seedling establishment is primarily seed-limited, but that microclimate is also important for the establishment of some native seeds. We found that exotic species were able to capitalize on the disturbance and outcompeted the native species, but reducing seed-limitations by sowing more native seeds and increasing available microclimates by raking or tilling may increase native species’ success at the establishment phase.

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