Pub Date : 2022-08-10DOI: 10.1674/0003-0031-188.1.1
Allison M. Scott, J. Gilbert, J. Pauli
Abstract. Small mammals are ubiquitous members of vertebrate communities that are sensitive to habitat change. In the Great Lakes region of North America, small mammal communities have changed rapidly, but experimental tests of potential mechanisms are lacking. Using a before-after, control-treatment design, we quantified the response of small mammals to single-tree selection harvest in Laurentian hardwood forests of Wisconsin, United States. We documented changes in forest structure and small mammal abundance, species diversity, and community similarity from silvicultural treatment. Treatment reduced tree density and canopy cover and increased mean tree diameter, woody stem density, variation in woody stem density, and volume of coarse woody debris. Peromyscus and northern short-tailed shrews (Blarina brevicauda) were dominant community members across treatments and years. White-footed mice (P. leucopus) outnumbered woodland deer mice (P. maniculatus gracilis) before treatment, but declined by almost fifty percent after treatment; deer mice and total rodent (i.e., Rodentia) abundances were unchanged. Small mammal species diversity increased twofold following treatment. Our experiment identified species-specific responses within Peromyscus to timber harvest: white-footed mice, the numerically dominant and generalist species, were most sensitive to habitat change, and their response produced cascading effects to small mammal community structure. Future experiments should assess these small mammal responses in a multi-year framework and quantify their effects on the broader vertebrate community.
{"title":"Population and Community Responses of Small Mammals to Single-tree Selection Harvest in Laurentian Hardwood Forests","authors":"Allison M. Scott, J. Gilbert, J. Pauli","doi":"10.1674/0003-0031-188.1.1","DOIUrl":"https://doi.org/10.1674/0003-0031-188.1.1","url":null,"abstract":"Abstract. Small mammals are ubiquitous members of vertebrate communities that are sensitive to habitat change. In the Great Lakes region of North America, small mammal communities have changed rapidly, but experimental tests of potential mechanisms are lacking. Using a before-after, control-treatment design, we quantified the response of small mammals to single-tree selection harvest in Laurentian hardwood forests of Wisconsin, United States. We documented changes in forest structure and small mammal abundance, species diversity, and community similarity from silvicultural treatment. Treatment reduced tree density and canopy cover and increased mean tree diameter, woody stem density, variation in woody stem density, and volume of coarse woody debris. Peromyscus and northern short-tailed shrews (Blarina brevicauda) were dominant community members across treatments and years. White-footed mice (P. leucopus) outnumbered woodland deer mice (P. maniculatus gracilis) before treatment, but declined by almost fifty percent after treatment; deer mice and total rodent (i.e., Rodentia) abundances were unchanged. Small mammal species diversity increased twofold following treatment. Our experiment identified species-specific responses within Peromyscus to timber harvest: white-footed mice, the numerically dominant and generalist species, were most sensitive to habitat change, and their response produced cascading effects to small mammal community structure. Future experiments should assess these small mammal responses in a multi-year framework and quantify their effects on the broader vertebrate community.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45511120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-10DOI: 10.1674/0003-0031-188.1.127
R. Mercader, Logan R Appenfeller, Patrick O. McCoy, T. Sadikot, Joshua L. Smith
Abstract. Recolonization by native species following removal of invasive plant species can often be uneven and lead to the rapid increase of one or a few native plant species. This can result in the formation of a significant resource pulse that may consequently affect populations of herbivorous species and their natural enemies. Here we present results from observations of parasitism rates during a localized outbreak of the Asimina webworm moth, Omphalocera munroei, a locally monophagous herbivore of the common paw-paw. Asimina triloba. This outbreak initiated from locations of increased understory growth of A. triloba, following the removal of Amur Honeysuckle (Lonicera maackii). Parasitism rates during the outbreak reached 50%, with higher parasitism rates observed in larvae collected at the end of the local outbreak relative to those the year following the peak of the outbreak. Parasitism rates remained high 3 y after the end of the local O. munroei outbreak, indicating >7 y of high parasitoid densities. O. munroei emerges late in the growing season, making it fairly inaccessible as a host or prey to many generalist predators/parasitoids, which emerge earlier the following year. This suggests the O. munroei outbreak potentially contributed to an increase in natural enemy pressure of other native species in the community.
{"title":"Parasitoid Increase During an Outbreak of a Native Herbivorous Insect Following Small-scale Amur Honeysuckle (Lonicera maackii) Removal","authors":"R. Mercader, Logan R Appenfeller, Patrick O. McCoy, T. Sadikot, Joshua L. Smith","doi":"10.1674/0003-0031-188.1.127","DOIUrl":"https://doi.org/10.1674/0003-0031-188.1.127","url":null,"abstract":"Abstract. Recolonization by native species following removal of invasive plant species can often be uneven and lead to the rapid increase of one or a few native plant species. This can result in the formation of a significant resource pulse that may consequently affect populations of herbivorous species and their natural enemies. Here we present results from observations of parasitism rates during a localized outbreak of the Asimina webworm moth, Omphalocera munroei, a locally monophagous herbivore of the common paw-paw. Asimina triloba. This outbreak initiated from locations of increased understory growth of A. triloba, following the removal of Amur Honeysuckle (Lonicera maackii). Parasitism rates during the outbreak reached 50%, with higher parasitism rates observed in larvae collected at the end of the local outbreak relative to those the year following the peak of the outbreak. Parasitism rates remained high 3 y after the end of the local O. munroei outbreak, indicating >7 y of high parasitoid densities. O. munroei emerges late in the growing season, making it fairly inaccessible as a host or prey to many generalist predators/parasitoids, which emerge earlier the following year. This suggests the O. munroei outbreak potentially contributed to an increase in natural enemy pressure of other native species in the community.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49657271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-10DOI: 10.1674/0003-0031-188.1.102
Amanda L. Coleman, D. A. Wait
Abstract. Urban prairie “gardens/plots” are gaining popularity for providing similar ecological services as remnant and restored prairies, which are predominantly found in rural areas. However, it is not known to what extent small urban prairies can sustain the plant-pollinator interactions that are vital to both the insects and the plants. The goal of our research was to examine plant/pollinator interactions in three urban prairies in southwest Missouri and compare them to rural managed/restored prairies using a visit-based approach. Urban prairies were all in Springfield, Mo. and shared similar habitat matrices (within an area of 8 km2); rural prairies were located within 68 km of urban prairies, shared similar habitat matrices to each other, and shared soil edaphic characteristics with an urban prairie. From May through August 2018 in all six prairies, we observed the five most abundant forbs in bloom, the number of pollinator visits by bees, butterflies/moths, wasps, beetles, and flies; and, pollinator fidelity from dawn to dusk. The areas observed within a prairie, hereafter “plot(s)”, were determined randomly by where at least two plants of the same species, out of the five most abundant forbs, were located. Using these criteria of observations on the five most abundant species across six prairies and four months, a total of 66 forb species were identified, with 58 of the species native to tallgrass prairies. However, only eight of the 58 native forb species were shared across urban and rural prairies. Jaccard similarity indices indicate lower similarity of the five abundant forbs within urban plots (9%) when compared to rural plots (24%), and low similarity between urban and rural plots (9%). Insect visitation varied by prairie type (rural/urban), month, and insect group; however, urban plots received 61% of the total visits compared to 39% in rural plots. Bees accounted for 5913 visits out of 10,113 visits recorded; high bee visits were similar in urban and rural plots. Insect fidelity was over 97% and did not significantly differ between rural and urban prairies. Therefore, the lack of similarity among and across urban and rural prairies in dominant species did not affect insect visitation rates or fidelity in our study. Our results suggest that establishment and management of urban prairie gardens and plots of various size may sustain the same or greater levels of pollinator services as rural prairies.
{"title":"Urban Prairie Plots and Gardens Can Sustain Plant-Pollinator Interactions Similar to Established Rural Prairies","authors":"Amanda L. Coleman, D. A. Wait","doi":"10.1674/0003-0031-188.1.102","DOIUrl":"https://doi.org/10.1674/0003-0031-188.1.102","url":null,"abstract":"Abstract. Urban prairie “gardens/plots” are gaining popularity for providing similar ecological services as remnant and restored prairies, which are predominantly found in rural areas. However, it is not known to what extent small urban prairies can sustain the plant-pollinator interactions that are vital to both the insects and the plants. The goal of our research was to examine plant/pollinator interactions in three urban prairies in southwest Missouri and compare them to rural managed/restored prairies using a visit-based approach. Urban prairies were all in Springfield, Mo. and shared similar habitat matrices (within an area of 8 km2); rural prairies were located within 68 km of urban prairies, shared similar habitat matrices to each other, and shared soil edaphic characteristics with an urban prairie. From May through August 2018 in all six prairies, we observed the five most abundant forbs in bloom, the number of pollinator visits by bees, butterflies/moths, wasps, beetles, and flies; and, pollinator fidelity from dawn to dusk. The areas observed within a prairie, hereafter “plot(s)”, were determined randomly by where at least two plants of the same species, out of the five most abundant forbs, were located. Using these criteria of observations on the five most abundant species across six prairies and four months, a total of 66 forb species were identified, with 58 of the species native to tallgrass prairies. However, only eight of the 58 native forb species were shared across urban and rural prairies. Jaccard similarity indices indicate lower similarity of the five abundant forbs within urban plots (9%) when compared to rural plots (24%), and low similarity between urban and rural plots (9%). Insect visitation varied by prairie type (rural/urban), month, and insect group; however, urban plots received 61% of the total visits compared to 39% in rural plots. Bees accounted for 5913 visits out of 10,113 visits recorded; high bee visits were similar in urban and rural plots. Insect fidelity was over 97% and did not significantly differ between rural and urban prairies. Therefore, the lack of similarity among and across urban and rural prairies in dominant species did not affect insect visitation rates or fidelity in our study. Our results suggest that establishment and management of urban prairie gardens and plots of various size may sustain the same or greater levels of pollinator services as rural prairies.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44860989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-10DOI: 10.1674/0003-0031-188.1.119
G. Shields
Abstract. Black fly larval collection sites at three rivers in central Washington state all possess taxa of the Simulium arcticum Malloch complex with the autosomal inversion, IS-1, in high enough frequency to test for Hardy-Weinberg equilibrium independently at each site. Such tests determine reproductive status of the taxa present. These situations in which the IS-1 autosomal inversion is in relative high frequency are rare. Moreover, earlier molecular comparisons suggest a single taxon for the S. arcticum complex and cytogenetic studies at the local level may or may not support earlier molecular work. Such knowledge could further our understanding of the proper taxonomy of these taxa, that is, whether they are good biological species or not. I scored the three genotypes of the IS-1 inversion in 247 larvae to test the reproductive status of populations of three members of the Simulium arcticum complex (Simulium brevicercum, S. saxosum, and the newly discovered cytotype (S. arcticum IIL- 81) at the Methow, Entiat and Wenatchee rivers of Washington state. In all three cases, larvae conformed to Hardy-Weinberg equilibrium, suggesting these populations were panmictic when the collections were made. Thus, these results support earlier molecular work and indicate that the three taxa at these sites can freely interbreed.
{"title":"Reproductive Status of Several Members of the Simulium arcticum Complex (Diptera: Simuliidae) in Three Populations in Central Washington State","authors":"G. Shields","doi":"10.1674/0003-0031-188.1.119","DOIUrl":"https://doi.org/10.1674/0003-0031-188.1.119","url":null,"abstract":"Abstract. Black fly larval collection sites at three rivers in central Washington state all possess taxa of the Simulium arcticum Malloch complex with the autosomal inversion, IS-1, in high enough frequency to test for Hardy-Weinberg equilibrium independently at each site. Such tests determine reproductive status of the taxa present. These situations in which the IS-1 autosomal inversion is in relative high frequency are rare. Moreover, earlier molecular comparisons suggest a single taxon for the S. arcticum complex and cytogenetic studies at the local level may or may not support earlier molecular work. Such knowledge could further our understanding of the proper taxonomy of these taxa, that is, whether they are good biological species or not. I scored the three genotypes of the IS-1 inversion in 247 larvae to test the reproductive status of populations of three members of the Simulium arcticum complex (Simulium brevicercum, S. saxosum, and the newly discovered cytotype (S. arcticum IIL- 81) at the Methow, Entiat and Wenatchee rivers of Washington state. In all three cases, larvae conformed to Hardy-Weinberg equilibrium, suggesting these populations were panmictic when the collections were made. Thus, these results support earlier molecular work and indicate that the three taxa at these sites can freely interbreed.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49516081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.1674/0003-0031-187.2.243
Brad Ross, John J. Berger, Carolyn G. Mahan, L. Russo
Abstract. Utility rights-of-way (ROW) serve as nesting areas and maintain a high diversity of early successional birds. ROW incorporating wire zone–border zone and integrated vegetation management can be used as examples of early successional habitat management for bird conservation more generally in the Northeastern United States, given artificial disturbances not created solely for natural resource conservation comprise approximately 80% of early successional habitats. The objective of our study was to determine the effect of herbicide and mechanical vegetation management approaches on the abundance, species richness, and reproductive success of breeding bird species occupying an electric transmission line ROW in central Pennsylvania. The overall abundance of birds was significantly lower within the wire and border management zones, following initiation of a new vegetation management cycle at State Game Lands (SGL 33) than in the years prior to management. Sections of ROW with no border zones contained the lowest abundance and species richness of breeding birds compared to sections with borders prior to the initiation of a new management cycle. Sections of ROW with no border zones and mowing sections had the lowest bird abundance and species richness of all ROW sections at the onset of a new management cycle, and contained the lowest number of bird species displaying evidence of breeding, both prior to and at the beginning of management cycles. Sections of ROW managed using herbicides were comparable or more beneficial to bird communities in terms of abundance, species richness, indices of productivity, and nesting success than sections maintained via mechanical treatments (mowing and hand cutting), both at the end and beginning of management cycles within a forested landscape in the central Appalachian Mountains and surrounding forested regions in the northeastern United States.
{"title":"Species Richness, Abundance, and Productivity of Birds Along a Powerline Right-of-way within a Forested Landscape, Northeastern United States","authors":"Brad Ross, John J. Berger, Carolyn G. Mahan, L. Russo","doi":"10.1674/0003-0031-187.2.243","DOIUrl":"https://doi.org/10.1674/0003-0031-187.2.243","url":null,"abstract":"Abstract. Utility rights-of-way (ROW) serve as nesting areas and maintain a high diversity of early successional birds. ROW incorporating wire zone–border zone and integrated vegetation management can be used as examples of early successional habitat management for bird conservation more generally in the Northeastern United States, given artificial disturbances not created solely for natural resource conservation comprise approximately 80% of early successional habitats. The objective of our study was to determine the effect of herbicide and mechanical vegetation management approaches on the abundance, species richness, and reproductive success of breeding bird species occupying an electric transmission line ROW in central Pennsylvania. The overall abundance of birds was significantly lower within the wire and border management zones, following initiation of a new vegetation management cycle at State Game Lands (SGL 33) than in the years prior to management. Sections of ROW with no border zones contained the lowest abundance and species richness of breeding birds compared to sections with borders prior to the initiation of a new management cycle. Sections of ROW with no border zones and mowing sections had the lowest bird abundance and species richness of all ROW sections at the onset of a new management cycle, and contained the lowest number of bird species displaying evidence of breeding, both prior to and at the beginning of management cycles. Sections of ROW managed using herbicides were comparable or more beneficial to bird communities in terms of abundance, species richness, indices of productivity, and nesting success than sections maintained via mechanical treatments (mowing and hand cutting), both at the end and beginning of management cycles within a forested landscape in the central Appalachian Mountains and surrounding forested regions in the northeastern United States.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45966356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.1674/0003-0031-187.2.210
Joseph M. Redinger, M. Gifford
Abstract. Insectivorous lizards can alter arthropod community structure and composition. Collared lizards (Crotaphytus collaris) are believed to be keystone predators for Ozark glade grasshopper (Orthoptera) communities by increasing species richness on smaller glades. However, the interaction between collared lizard presence and glade area on orthopteran species richness has been inconsistent between studies on glades in southeastern Missouri. In this study, we explored the effects of collared lizard presence on orthopteran abundance, diversity, and assemblage composition in Ozark glades located in northern Arkansas. We found the presence of predatory collared lizard populations significantly affected orthopteran assemblage composition. However, the presence of collared lizards did not affect orthopteran abundance or diversity. Additionally, there were no interaction effects between collared lizard presence and glade area on orthopteran assemblages. We did find that month had the most consistent effect on orthopteran abundance, diversity, and assemblage composition. These results contrast with other studies that indicate collared lizards influence orthopteran species richness on other glade communities within the region. In this study, seasonal effects, glade area, and unmeasured bottom-up effects appear more important for determining orthopteran diversity than predation. Our results provide further evidence that the strength of top-down effects can vary across a predator's range and could have implications for glade restoration plans in the region.
{"title":"The Effect of an Insectivorous Lizard Predator (Crotaphytus collaris) on Ozark Glade Orthopteran Assemblages","authors":"Joseph M. Redinger, M. Gifford","doi":"10.1674/0003-0031-187.2.210","DOIUrl":"https://doi.org/10.1674/0003-0031-187.2.210","url":null,"abstract":"Abstract. Insectivorous lizards can alter arthropod community structure and composition. Collared lizards (Crotaphytus collaris) are believed to be keystone predators for Ozark glade grasshopper (Orthoptera) communities by increasing species richness on smaller glades. However, the interaction between collared lizard presence and glade area on orthopteran species richness has been inconsistent between studies on glades in southeastern Missouri. In this study, we explored the effects of collared lizard presence on orthopteran abundance, diversity, and assemblage composition in Ozark glades located in northern Arkansas. We found the presence of predatory collared lizard populations significantly affected orthopteran assemblage composition. However, the presence of collared lizards did not affect orthopteran abundance or diversity. Additionally, there were no interaction effects between collared lizard presence and glade area on orthopteran assemblages. We did find that month had the most consistent effect on orthopteran abundance, diversity, and assemblage composition. These results contrast with other studies that indicate collared lizards influence orthopteran species richness on other glade communities within the region. In this study, seasonal effects, glade area, and unmeasured bottom-up effects appear more important for determining orthopteran diversity than predation. Our results provide further evidence that the strength of top-down effects can vary across a predator's range and could have implications for glade restoration plans in the region.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48102957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.1674/0003-0031-187.2.195
C. Schalk, Yuhui Weng, C. Adams, Daniel Sáenz
Abstract. Patterns of species' occurrences across space and time are fundamental components to understanding their ecology, as this variation often reflects responses to local environmental gradients. We built species-specific models to understand the spatial and temporal factors predicting captures and activity of five snake species in upland pine forests: copperhead (Agkistrodon contortrix), racer (Coluber constrictor), coachwhip (Masticophis flagellum), western ratsnake (Pantherophis obsoletus), and western ribbonsnake (Thamnophis proximus). From mid-May to mid-July across 3 y (2018, 2019, 2020), we monitored boxtraps in two upland pine forests experiencing different management regimes: (1) subjected to frequent thinning and prescribed burning, and (2) subjected to infrequent thinning and prescribed burning. Significantly more copperheads and western ribbonsnakes were captured at the infrequently thinned and burned forest, whereas significantly more racers were captured at forest subjected to frequent thinning and burning. As the summer progressed, captures decreased each subsequent month for both racers and western ratsnakes, with the fewest captures in July. Western ratsnakes were the only species to exhibit a response to the weather in that activity decreased with increasing rainfall. No variables were significant predictors of coachwhip captures. The variation in captures across space may be attributed to the physiological tolerances of each species based on their habitat preferences or differences in prey availability at each forest. Interactions between the physiological tolerances, foraging behaviors, or their reproductive phenology may be underlying the temporal variation in activity patterns.
{"title":"Spatiotemporal Patterns of Snake Captures and Activity in Upland Pine Forests","authors":"C. Schalk, Yuhui Weng, C. Adams, Daniel Sáenz","doi":"10.1674/0003-0031-187.2.195","DOIUrl":"https://doi.org/10.1674/0003-0031-187.2.195","url":null,"abstract":"Abstract. Patterns of species' occurrences across space and time are fundamental components to understanding their ecology, as this variation often reflects responses to local environmental gradients. We built species-specific models to understand the spatial and temporal factors predicting captures and activity of five snake species in upland pine forests: copperhead (Agkistrodon contortrix), racer (Coluber constrictor), coachwhip (Masticophis flagellum), western ratsnake (Pantherophis obsoletus), and western ribbonsnake (Thamnophis proximus). From mid-May to mid-July across 3 y (2018, 2019, 2020), we monitored boxtraps in two upland pine forests experiencing different management regimes: (1) subjected to frequent thinning and prescribed burning, and (2) subjected to infrequent thinning and prescribed burning. Significantly more copperheads and western ribbonsnakes were captured at the infrequently thinned and burned forest, whereas significantly more racers were captured at forest subjected to frequent thinning and burning. As the summer progressed, captures decreased each subsequent month for both racers and western ratsnakes, with the fewest captures in July. Western ratsnakes were the only species to exhibit a response to the weather in that activity decreased with increasing rainfall. No variables were significant predictors of coachwhip captures. The variation in captures across space may be attributed to the physiological tolerances of each species based on their habitat preferences or differences in prey availability at each forest. Interactions between the physiological tolerances, foraging behaviors, or their reproductive phenology may be underlying the temporal variation in activity patterns.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41958212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.1674/0003-0031-187.2.113
Alexandria D. Szakacs, A. Krings, T. R. Wentworth
Abstract. Historical accounts describe savanna-like conditions over portions of the Piedmont of the southeastern United States dating at least as far back as the 1500s. These open habitats are thought to have declined because of human development, fire suppression, and loss of native grazing animals. Unfortunately, conservation efforts to restore and sustain Piedmont savanna are hampered by our current rudimentary understanding of community assembly and maintenance dynamics. Such understanding would be facilitated by a robust classification of species into specialist and generalist guilds related to canopy openness, a classification that is currently unavailable on a broad scale. Consequently, our objective was to develop a shade-tolerance classification for the upland Piedmont herbaceous flora of the Carolinas and Virginia, based on quantitative plot data from the region. To achieve this objective, we utilized a dataset of plot records (representing natural and semi-natural vegetation) from the Carolina Vegetation Survey. These are permanent plots on public and private land that were surveyed between 1977 and 2015. Following quality control, the dataset contained 1300 plots and 1550 species (including 835 native herbaceous species after single occurrences were removed), with species abundances in plots reported in cover classes. We estimated the canopy cover of each plot from the cover codes of its tree species and assigned each plot to habitat shade classes: open (<25% canopy cover; n = 63), semi-open (25–75% canopy cover; n=140), or closed (>75% canopy cover; n=1097). We calculated point biserial correlation coefficients (rpb), which provided a positive or negative value for each species, dependent on its abundance and habitat association. We considered single (open, semi-open, or closed) and combined (open+semi-open, closed+semi-open, or open+closed) habitat classes during our analysis. Of the 835 native herbaceous species in the dataset, we found 141 (17%) to be heliophytes (specialists of open habitats with canopy cover <25%), and only 81 (10%) to be sciophytes (specialists of closed habitats with canopy cover >75%), despite 84% of plots in the dataset being classified as closed habitats. Our work suggests that open and semi-open habitats may contain a disproportionate diversity of regional herbaceous flora and provides the first quantitative shade-tolerance classification for over 800 herbaceous species. This work provides a resource that can be used by field biologists and land managers to identify heliophyte communities, and to assess the success of habitat restoration and creation efforts.
{"title":"Shade-Tolerance Classification of the Upland Herbaceous Flora of the Carolina and Virginia Piedmont","authors":"Alexandria D. Szakacs, A. Krings, T. R. Wentworth","doi":"10.1674/0003-0031-187.2.113","DOIUrl":"https://doi.org/10.1674/0003-0031-187.2.113","url":null,"abstract":"Abstract. Historical accounts describe savanna-like conditions over portions of the Piedmont of the southeastern United States dating at least as far back as the 1500s. These open habitats are thought to have declined because of human development, fire suppression, and loss of native grazing animals. Unfortunately, conservation efforts to restore and sustain Piedmont savanna are hampered by our current rudimentary understanding of community assembly and maintenance dynamics. Such understanding would be facilitated by a robust classification of species into specialist and generalist guilds related to canopy openness, a classification that is currently unavailable on a broad scale. Consequently, our objective was to develop a shade-tolerance classification for the upland Piedmont herbaceous flora of the Carolinas and Virginia, based on quantitative plot data from the region. To achieve this objective, we utilized a dataset of plot records (representing natural and semi-natural vegetation) from the Carolina Vegetation Survey. These are permanent plots on public and private land that were surveyed between 1977 and 2015. Following quality control, the dataset contained 1300 plots and 1550 species (including 835 native herbaceous species after single occurrences were removed), with species abundances in plots reported in cover classes. We estimated the canopy cover of each plot from the cover codes of its tree species and assigned each plot to habitat shade classes: open (<25% canopy cover; n = 63), semi-open (25–75% canopy cover; n=140), or closed (>75% canopy cover; n=1097). We calculated point biserial correlation coefficients (rpb), which provided a positive or negative value for each species, dependent on its abundance and habitat association. We considered single (open, semi-open, or closed) and combined (open+semi-open, closed+semi-open, or open+closed) habitat classes during our analysis. Of the 835 native herbaceous species in the dataset, we found 141 (17%) to be heliophytes (specialists of open habitats with canopy cover <25%), and only 81 (10%) to be sciophytes (specialists of closed habitats with canopy cover >75%), despite 84% of plots in the dataset being classified as closed habitats. Our work suggests that open and semi-open habitats may contain a disproportionate diversity of regional herbaceous flora and provides the first quantitative shade-tolerance classification for over 800 herbaceous species. This work provides a resource that can be used by field biologists and land managers to identify heliophyte communities, and to assess the success of habitat restoration and creation efforts.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43556594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.1674/0003-0031-187.2.225
Sabrina E. Thiels, C. R. Edwards, T. Bonner
Abstract. Species richness and abundances of fluvial specialist fishes often decrease within waters impounded by dams, but mechanisms underlying these decreases are poorly understood. Purpose of this study was to assess the effects of impounded water on fluvial specialist Greenthroat Darter Etheostoma lepidum by quantifying differences in life history (i.e., age structure, life span), reproduction (i.e., gonadosomatic index [GSI], stages of ovarian development), and stomach contents (i.e., diet items and parasites) between a population taken from a lentic environment (Lake Site) and a lotic environment (River Site). Among fishes taken from both sites, Greenthroat Darters lived up to 1.5 y, spawned for 11 mo, and consumed primarily aquatic insects and crustaceans. Differences in reproduction were not detected between populations at the Lake Site and at the River Site. Greenthroat Darters taken from Lake Site consumed fewer diet items, fewer aquatic insects, and greater number of crustaceans than those taken from River Site; however, diet weight, percent stomach fullness, and percent empty stomachs were similar between sites. Greenthroat Darters taken from Lake Site exhibited lower condition factors than those taken from River Site, which corresponded with a greater number of parasites (i.e., Acanthocephala and Nematoda) in individuals taken from Lake Site. Differences quantified herein were not sufficient to cause extirpation of Greenthroat Darters in the impounded waters, given the species has persisted in the impounded water at least since the late 1800s; however, differences in diets and parasites might explain the lower abundance of Greenthroat Darters in Lake Site compared to River Site.
{"title":"Assessing Effects of Impounded Water on Life History, Reproduction, and Diets of a Fluvial Specialist Fish","authors":"Sabrina E. Thiels, C. R. Edwards, T. Bonner","doi":"10.1674/0003-0031-187.2.225","DOIUrl":"https://doi.org/10.1674/0003-0031-187.2.225","url":null,"abstract":"Abstract. Species richness and abundances of fluvial specialist fishes often decrease within waters impounded by dams, but mechanisms underlying these decreases are poorly understood. Purpose of this study was to assess the effects of impounded water on fluvial specialist Greenthroat Darter Etheostoma lepidum by quantifying differences in life history (i.e., age structure, life span), reproduction (i.e., gonadosomatic index [GSI], stages of ovarian development), and stomach contents (i.e., diet items and parasites) between a population taken from a lentic environment (Lake Site) and a lotic environment (River Site). Among fishes taken from both sites, Greenthroat Darters lived up to 1.5 y, spawned for 11 mo, and consumed primarily aquatic insects and crustaceans. Differences in reproduction were not detected between populations at the Lake Site and at the River Site. Greenthroat Darters taken from Lake Site consumed fewer diet items, fewer aquatic insects, and greater number of crustaceans than those taken from River Site; however, diet weight, percent stomach fullness, and percent empty stomachs were similar between sites. Greenthroat Darters taken from Lake Site exhibited lower condition factors than those taken from River Site, which corresponded with a greater number of parasites (i.e., Acanthocephala and Nematoda) in individuals taken from Lake Site. Differences quantified herein were not sufficient to cause extirpation of Greenthroat Darters in the impounded waters, given the species has persisted in the impounded water at least since the late 1800s; however, differences in diets and parasites might explain the lower abundance of Greenthroat Darters in Lake Site compared to River Site.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47288633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.1674/0003-0031-187.2.279
C. Heun, Hannah L. Schley, S. Crimmins
Abstract. The ability of an animal to acquire enough food to meet its caloric needs is key to its survival and fitness. Understanding the composition of that animal's diet is a crucial element to consider when assessing the species' health and overall role in its ecosystem. We conducted a dietary study of Northern River Otter (Lontra canadensis) at 18 sites across 12 different watersheds in Wisconsin, U.S.A., from summer 2017 through winter 2018. We report the frequency of prey remains found in river otter scats (n = 190) collected at these sites. Fish of any kind appeared in 86% (n = 163) of all scat samples, while crayfish (Cambaridae) were the most commonly occurring individual prey item, appearing in 62% (n = 117) of all scat samples. The second most common prey groups were the bottom feeder fish (Catostomidae and Cyprinidae) group and the panfish (Centrarchidae) group, which both occurred in 45% of all scats. While identifying prey species, we found small, spherical objects that did not appear to be of biological origin in 48% (n = 92) of all scats. After testing the objects using multiple approaches, we confirmed the objects as microbeads, defined as small beads of plastic composition no larger than 5mm in size. This is the first recorded observation of plastic microbeads associated with river otters in North America, and may indicate bioaccumulation of these objects in inland waterways.
{"title":"River Otter Feeding Habits in Wisconsin, U.S.A.: Evidence of Microbead Contamination","authors":"C. Heun, Hannah L. Schley, S. Crimmins","doi":"10.1674/0003-0031-187.2.279","DOIUrl":"https://doi.org/10.1674/0003-0031-187.2.279","url":null,"abstract":"Abstract. The ability of an animal to acquire enough food to meet its caloric needs is key to its survival and fitness. Understanding the composition of that animal's diet is a crucial element to consider when assessing the species' health and overall role in its ecosystem. We conducted a dietary study of Northern River Otter (Lontra canadensis) at 18 sites across 12 different watersheds in Wisconsin, U.S.A., from summer 2017 through winter 2018. We report the frequency of prey remains found in river otter scats (n = 190) collected at these sites. Fish of any kind appeared in 86% (n = 163) of all scat samples, while crayfish (Cambaridae) were the most commonly occurring individual prey item, appearing in 62% (n = 117) of all scat samples. The second most common prey groups were the bottom feeder fish (Catostomidae and Cyprinidae) group and the panfish (Centrarchidae) group, which both occurred in 45% of all scats. While identifying prey species, we found small, spherical objects that did not appear to be of biological origin in 48% (n = 92) of all scats. After testing the objects using multiple approaches, we confirmed the objects as microbeads, defined as small beads of plastic composition no larger than 5mm in size. This is the first recorded observation of plastic microbeads associated with river otters in North America, and may indicate bioaccumulation of these objects in inland waterways.","PeriodicalId":50802,"journal":{"name":"American Midland Naturalist","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45142204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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