Eric Gese, Cole A. Bleke, Shane B. Roberts, Paul Atwood, Pat Terletzky
Density-independent and density-dependent population regulation has long been a subject of investigation. We examined density-dependent and density-independent factors on growth rates of pronghorn (Antilocapra americana (Ord, 1815)) using a retrospective analysis of population survey data. Across Idaho, we found as the proportion of the subpopulation harvested the previous year increased, growth rates increased. Similarly, as fawn recruitment increased, growth rates increased. We also found when the growth rate in the previous year increased, the growth rate the subsequent year decreased. When subpopulations were examined independently, we found in a low-elevation desert subpopulation, growth rates were influenced by growth the previous year. In an agricultural-dominated site, growth rates were influenced by fawn recruitment in the current year and maximum temperature the previous fall. Growth rates in a mid-elevation shrub-steppe site were influenced by drought severity prior to parturition and the growth rates from the previous year. Growth rates in two mountain valley subpopulations were influenced by measures of vegetative greenness. At the statewide scale, while managers may strive for increased numbers of pronghorn, density dependence will limit the ability for a region-wide numerical response. On the localized scale, drivers of growth were temporally and spatially-explicit, and biologists must consider site-specific actions.
{"title":"Population growth rates of pronghorn: influence of temporally and spatially explicit conditions, density dependence, and scale","authors":"Eric Gese, Cole A. Bleke, Shane B. Roberts, Paul Atwood, Pat Terletzky","doi":"10.1139/cjz-2023-0113","DOIUrl":"https://doi.org/10.1139/cjz-2023-0113","url":null,"abstract":"Density-independent and density-dependent population regulation has long been a subject of investigation. We examined density-dependent and density-independent factors on growth rates of pronghorn (Antilocapra americana (Ord, 1815)) using a retrospective analysis of population survey data. Across Idaho, we found as the proportion of the subpopulation harvested the previous year increased, growth rates increased. Similarly, as fawn recruitment increased, growth rates increased. We also found when the growth rate in the previous year increased, the growth rate the subsequent year decreased. When subpopulations were examined independently, we found in a low-elevation desert subpopulation, growth rates were influenced by growth the previous year. In an agricultural-dominated site, growth rates were influenced by fawn recruitment in the current year and maximum temperature the previous fall. Growth rates in a mid-elevation shrub-steppe site were influenced by drought severity prior to parturition and the growth rates from the previous year. Growth rates in two mountain valley subpopulations were influenced by measures of vegetative greenness. At the statewide scale, while managers may strive for increased numbers of pronghorn, density dependence will limit the ability for a region-wide numerical response. On the localized scale, drivers of growth were temporally and spatially-explicit, and biologists must consider site-specific actions.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria Celeste Yuvero, Maria Eugenia Torroglosa, Betina J. Lomovasky, Juliana Gimenez
The size at first maturity of the bivalve Mytilus platensis d’Orbigny, 1842 was estimated in the intertidal population of Villa Gesell (37° 15'S; 56° 57'W), Buenos Aires, Argentina. We hypothesize a variation in population maturity associated with shell length (SL) and differences between females and males. Individuals were analyzed histologically, sexed (females and males), and classified as mature and immature. We carried out a Kernel Density Estimation (KDE) to allow us to visualize the distribution of the classifications based on the SL and used a Generalized Linear Model (GLM) to study the size at first sexual maturity for the population and between sexes. Our results showed immature specimens with reduced development in acini and expanded connective tissue. Mature males and females showed the acini expanded and filled with vitellogenic oocytes and spermatozoa, respectively. The size at first sexual maturity at which 50% of the population was mature (SL50) was 11.80 mm SL for all population, while SL50 was 11.42 mm in females and 10.83 mm in males. We determined significant interaction between SL and sex (p < 0.05). We conclude that the knowledge of the reproductive aspects in intertidal populations is essential for the development of a potential fishing resource.
在比耶斯尔(37°15'S)潮间带种群中测定了1842年双壳贝贻贝(Mytilus platensis d 'Orbigny, 1842)初成熟时的大小;西经56°57′，阿根廷布宜诺斯艾利斯。我们假设种群成熟度的变化与壳长(SL)和雌雄之间的差异有关。对个体进行组织学、性别(雌性和雄性)分析，并将其分为成熟和不成熟。我们进行了核密度估计(KDE)，使我们能够可视化基于SL的分类分布，并使用广义线性模型(GLM)来研究群体和性别之间的初次性成熟大小。我们的结果显示，未成熟标本的腺泡发育减少，结缔组织扩大。成熟雄性和雌性的腺泡分别扩大，充满卵黄细胞和精子。50%种群成熟时的初次性成熟尺寸(SL50)为11.80 mm SL，而雌性SL50为11.42 mm，雄性SL50为10.83 mm。我们发现SL和性别之间存在显著的相互作用(p <0.05)。我们的结论是，了解潮间带种群的生殖方面的知识对于开发潜在的渔业资源是必不可少的。
{"title":"Size at first maturity on the mussel Mytilus platensis d’Orbigny, 1842 at the Southwest Atlantic","authors":"Maria Celeste Yuvero, Maria Eugenia Torroglosa, Betina J. Lomovasky, Juliana Gimenez","doi":"10.1139/cjz-2023-0070","DOIUrl":"https://doi.org/10.1139/cjz-2023-0070","url":null,"abstract":"The size at first maturity of the bivalve Mytilus platensis d’Orbigny, 1842 was estimated in the intertidal population of Villa Gesell (37° 15'S; 56° 57'W), Buenos Aires, Argentina. We hypothesize a variation in population maturity associated with shell length (SL) and differences between females and males. Individuals were analyzed histologically, sexed (females and males), and classified as mature and immature. We carried out a Kernel Density Estimation (KDE) to allow us to visualize the distribution of the classifications based on the SL and used a Generalized Linear Model (GLM) to study the size at first sexual maturity for the population and between sexes. Our results showed immature specimens with reduced development in acini and expanded connective tissue. Mature males and females showed the acini expanded and filled with vitellogenic oocytes and spermatozoa, respectively. The size at first sexual maturity at which 50% of the population was mature (SL50) was 11.80 mm SL for all population, while SL50 was 11.42 mm in females and 10.83 mm in males. We determined significant interaction between SL and sex (p < 0.05). We conclude that the knowledge of the reproductive aspects in intertidal populations is essential for the development of a potential fishing resource.
","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hugo Guzmán Intzin, Carmen Alejo-Plata, Miguel Angel del Rio Portilla, Saúl Serrano Guzmán, Pedro Cervantes-Hernández
Squid Lolliguncula panamensis (Hoyle, 1904) is of commercial and ecological importance in the Gulf of Tehuantepec (southeastern Mexico). This study examines the mode of oocyte development, packing in the ovary, and spawning pattern of this understudied species. L. panamensis presents a synchronous oocyte growth in batches, with multiple spawning, with the presence of post-ovulatory follicles and atretic follicles, including the constant presence of pre-vitellogenic and vitellogenic oocytes. The size frequencies of oocytes of ripe ovaries exhibit a pronounced morphological and size separation between the late yolk stage and mature oocytes, suggesting that the oocytes pass through this size range very fast. These oocytes adopt a geometrical shape that makes their packing efficient for spawning. One three-dimensional packing of vitellogenic oocytes (scutoid type) in the ovary was observed. The results of our study suggest that the spawning behavior of L. panamensis may constitute an opportunistic reproductive strategy in which individuals present multiple spawning over a brief period. We suggest that this strategy might be a response to complex regional oceanographic conditions of the Gulf of Tehuantepec.
{"title":"Oocyte development, packing in the ovary, and spawning pattern of squid Lolliguncula panamensis in the Mexican South Pacific","authors":"Hugo Guzmán Intzin, Carmen Alejo-Plata, Miguel Angel del Rio Portilla, Saúl Serrano Guzmán, Pedro Cervantes-Hernández","doi":"10.1139/cjz-2023-0124","DOIUrl":"https://doi.org/10.1139/cjz-2023-0124","url":null,"abstract":"Squid Lolliguncula panamensis (Hoyle, 1904) is of commercial and ecological importance in the Gulf of Tehuantepec (southeastern Mexico). This study examines the mode of oocyte development, packing in the ovary, and spawning pattern of this understudied species. L. panamensis presents a synchronous oocyte growth in batches, with multiple spawning, with the presence of post-ovulatory follicles and atretic follicles, including the constant presence of pre-vitellogenic and vitellogenic oocytes. The size frequencies of oocytes of ripe ovaries exhibit a pronounced morphological and size separation between the late yolk stage and mature oocytes, suggesting that the oocytes pass through this size range very fast. These oocytes adopt a geometrical shape that makes their packing efficient for spawning. One three-dimensional packing of vitellogenic oocytes (scutoid type) in the ovary was observed. The results of our study suggest that the spawning behavior of L. panamensis may constitute an opportunistic reproductive strategy in which individuals present multiple spawning over a brief period. We suggest that this strategy might be a response to complex regional oceanographic conditions of the Gulf of Tehuantepec.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135808265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grégory Bulté, Jessica A. Robichaud, Erika J. Shadlock, Steven J. Cooke, Gabriel Blouin-Demers
Mass mortality events appear to be increasing in intensity and frequency, so understanding their causes and consequences is imperative for wildlife conservation. We report on a mass mortality event in a population of Northern Map Turtles ( Graptemys geographica (LeSueur, 1817)). At a communal overwintering site, 142 carcasses (ca. 10% of population) were recovered, seemingly depredated by river otters ( Lontra canadensis (Schreber, 1777)). We compared the size and sex of the carcasses to those of turtles that survived. Smaller turtles and males were more likely to be depredated than larger turtles and females. Using captures made at the same overwintering site between 2003 and 2022, we assessed the vulnerability of this population to mass mortality events during winter. Nearly 60% of the 1875 turtles marked between 2003 and 2022 used the overwintering site where the mass mortality event occurred at least once. On average, turtles overwintered at the site at least 38% of the winters between their first and last capture. Our study shows how behaviour and physiology interact to predispose a species to mass mortality events and ecological traps. Protecting overwintering sites and minimizing human pressures affecting winter depredation may be essential for the preservation of certain turtle populations.
{"title":"Overwintering site fidelity and communal hibernation predispose Northern Map Turtles to mass mortality events","authors":"Grégory Bulté, Jessica A. Robichaud, Erika J. Shadlock, Steven J. Cooke, Gabriel Blouin-Demers","doi":"10.1139/cjz-2023-0127","DOIUrl":"https://doi.org/10.1139/cjz-2023-0127","url":null,"abstract":"Mass mortality events appear to be increasing in intensity and frequency, so understanding their causes and consequences is imperative for wildlife conservation. We report on a mass mortality event in a population of Northern Map Turtles ( Graptemys geographica (LeSueur, 1817)). At a communal overwintering site, 142 carcasses (ca. 10% of population) were recovered, seemingly depredated by river otters ( Lontra canadensis (Schreber, 1777)). We compared the size and sex of the carcasses to those of turtles that survived. Smaller turtles and males were more likely to be depredated than larger turtles and females. Using captures made at the same overwintering site between 2003 and 2022, we assessed the vulnerability of this population to mass mortality events during winter. Nearly 60% of the 1875 turtles marked between 2003 and 2022 used the overwintering site where the mass mortality event occurred at least once. On average, turtles overwintered at the site at least 38% of the winters between their first and last capture. Our study shows how behaviour and physiology interact to predispose a species to mass mortality events and ecological traps. Protecting overwintering sites and minimizing human pressures affecting winter depredation may be essential for the preservation of certain turtle populations.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136019135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metabolic rate is a key parameter in fish energy budgets that strongly influences the output of bioenergetics models. In this study, we tested the hypothesis that metabolic rate varies with growth history of age-1 largemouth bass Micropterus nigricans Cuvier, 1828. Two groups of fish were fed alternating maintenance or ad libitum rations of fathead minnow Pimephales promelas Rafinesque, 1820, so that over a 9-week period, initial and ending size of fish was similar. After 9 weeks, oxygen consumption was measured using static, closed respirometry. Although final body weight was similar between the two groups (means, 104–108 g), specific oxygen consumption for fish fed maintenance rations (0.094 mg O 2 g −2 h −1 ) was 38% less than that measured for fish fed ad libitum (0.152 mg O 2 g −2 h −1 ). Bioenergetics estimates of food consumption were similar to observed values for fish fed ad libitum (∼7% error), but for fish fed maintenance rations, the model overestimated food consumption by 65%. By accounting for changes in metabolic rate owing to reduced feeding, error in model estimates of food consumption was reduced. These findings shed new insight into factors associated with consumption-dependent error in bioenergetics models and highlight the importance of feeding history on metabolic rate of fish. Incorporating growth-dependent metabolism into bioenergetics models can improve model accuracy and allow fisheries biologists to make more informed decisions regarding fish growth and energetics.
代谢率是鱼类能量收支的一个关键参数，它强烈影响生物能量模型的输出。在这项研究中，我们验证了1岁大口黑鲈Micropterus nigricans (Cuvier, 1828)的代谢率随生长历史变化的假设。两组鱼交替饲喂1820年黑头鲦鱼(Pimephales promelas Rafinesque, 1820)维持或随意饲料，在9周的时间内，鱼的初始和最终尺寸相似。9周后，用静态闭式呼吸仪测量耗氧量。尽管两组鱼的最终体重相似(平均值为104-108 g)，但维持饲料的比耗氧量(0.094 mg O 2 g−2 h−1)比自由饲料的比耗氧量(0.152 mg O 2 g−2 h−1)少38%。食物消耗的生物能量估计值与观察到的自由饲料鱼的值相似(误差约7%)，但对于维持饲料鱼，该模型高估了65%的食物消耗。通过考虑由于摄食减少而引起的代谢率变化，减少了模型估计食物消耗的误差。这些发现为生物能量学模型中与消耗依赖误差相关的因素提供了新的见解，并强调了饲养历史对鱼类代谢率的重要性。将生长依赖性代谢纳入生物能量学模型可以提高模型的准确性，并允许渔业生物学家对鱼类生长和能量学做出更明智的决定。
{"title":"Effect of feeding history on metabolic rate of largemouth bass (<i>Micropterus nigricans</i>): implications for bioenergetics models","authors":"Steven H. Ranney, Steven R. Chipps, David H. Wahl","doi":"10.1139/cjz-2023-0047","DOIUrl":"https://doi.org/10.1139/cjz-2023-0047","url":null,"abstract":"Metabolic rate is a key parameter in fish energy budgets that strongly influences the output of bioenergetics models. In this study, we tested the hypothesis that metabolic rate varies with growth history of age-1 largemouth bass Micropterus nigricans Cuvier, 1828. Two groups of fish were fed alternating maintenance or ad libitum rations of fathead minnow Pimephales promelas Rafinesque, 1820, so that over a 9-week period, initial and ending size of fish was similar. After 9 weeks, oxygen consumption was measured using static, closed respirometry. Although final body weight was similar between the two groups (means, 104–108 g), specific oxygen consumption for fish fed maintenance rations (0.094 mg O 2 g −2 h −1 ) was 38% less than that measured for fish fed ad libitum (0.152 mg O 2 g −2 h −1 ). Bioenergetics estimates of food consumption were similar to observed values for fish fed ad libitum (∼7% error), but for fish fed maintenance rations, the model overestimated food consumption by 65%. By accounting for changes in metabolic rate owing to reduced feeding, error in model estimates of food consumption was reduced. These findings shed new insight into factors associated with consumption-dependent error in bioenergetics models and highlight the importance of feeding history on metabolic rate of fish. Incorporating growth-dependent metabolism into bioenergetics models can improve model accuracy and allow fisheries biologists to make more informed decisions regarding fish growth and energetics.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136318664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rohab Batool, Juriyah Jenan, Madeline Schuster, Rosalind L Murray
As temperatures warm in response to anthropogenic changes (climate change and urbanization), animals must respond adaptively to these changes or be displaced. Here, we use community science data (iNaturalist and BugGuide) to show that melanisation in larval monarch butterflies (Danaus plexippus (Linnaeus, 1758)); an endangered species in Canada) is correlated with latitude and temperature across a latitudinal gradient, indicating likely use in thermoregulation. We also predicted that melanisation would decrease in cities where temperatures are consistently higher than rural areas, however we found that while melanisation was lower in urban areas, it was not statistically significant. Our results demonstrate the importance of considering life stage when assessing capacity for adaptation to anthropogenic change in vulnerable animal populations, like monarch butterflies. We also show the value of using community science to sample species (particular those of most concern) distributions across the landscape.
{"title":"How do latitude and urban heat islands affect monarch butterfly (Danaus plexippus) larval melanisation?","authors":"Rohab Batool, Juriyah Jenan, Madeline Schuster, Rosalind L Murray","doi":"10.1139/cjz-2023-0099","DOIUrl":"https://doi.org/10.1139/cjz-2023-0099","url":null,"abstract":"As temperatures warm in response to anthropogenic changes (climate change and urbanization), animals must respond adaptively to these changes or be displaced. Here, we use community science data (iNaturalist and BugGuide) to show that melanisation in larval monarch butterflies (Danaus plexippus (Linnaeus, 1758)); an endangered species in Canada) is correlated with latitude and temperature across a latitudinal gradient, indicating likely use in thermoregulation. We also predicted that melanisation would decrease in cities where temperatures are consistently higher than rural areas, however we found that while melanisation was lower in urban areas, it was not statistically significant. Our results demonstrate the importance of considering life stage when assessing capacity for adaptation to anthropogenic change in vulnerable animal populations, like monarch butterflies. We also show the value of using community science to sample species (particular those of most concern) distributions across the landscape.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135218002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vanessa Poirier, Barbara Frei, Mathilde Lefvert, Ana Morales, Kyle Hamish Elliott
Stopovers are the most energy- and time-consuming events during avian migration, yet individuals of certain species make long stopovers to moult (‘moult migration’). Requiring abundant energy and a prolonged stay, moult migrants should occupy small stopover home ranges in resource-rich habitats. Understanding migrant behaviour at their stopovers is critical for implementing conservation efforts for declining Neotropical passerines. To examine the stopover timing and habitat use of one such moult migrating passerine, we radio-tagged 18 moulting and 4 post-moult Tennessee Warblers (Leiothlypis peregrina A. Wilson, 1811) at an autumn stopover site. Although our data were biased towards one sampling year, moult migrants generally arrived at the stopover site earlier (average = 2 August) than post-moult migrants (average = 12 September). Moult migrants also stayed longer (46 ± 5 days) than post-moult migrants (8 ± 6 days) and had large overlapping stopover home ranges (~15 ha) that were dependent on high abundance of forest (%) and forest edge (m). We conclude that Tennessee Warblers occupied forested stopover sites within a peri-urban landscape where they successfully moulted before continuing migration. This study illustrates the importance of including stopover sites in conservation plans, particularly in cities where quality habitats are scarce.
中途停留是鸟类迁徙过程中最耗费精力和时间的事情，但某些物种的个体会在中途停留很长时间来换羽(“换羽迁徙”)。换毛候鸟需要充足的能量和长时间的停留，它们应该在资源丰富的栖息地占据一小块中途停留的范围。了解候鸟在中途停留地的行为对于实施保护日益减少的新热带雀形目动物的努力至关重要。为了研究一种这样的换羽迁徙雀鸟的中途停留时间和栖息地利用，我们在一个秋季中途停留点对18只换羽的田纳西林莺和4只换羽后的田纳西林莺(leiothlyypis peregrina A. Wilson, 1811)进行了无线电标记。虽然我们的数据偏向于一个采样年，但蜕皮候鸟通常比蜕皮后候鸟(平均= 9月12日)更早到达中途停留点(平均= 8月2日)。换毛候鸟停留的时间(46±5天)也比换毛后候鸟停留的时间(8±6天)更长，并且有很大的重叠的中途停留范围(~15公顷)，这取决于森林的丰度(%)和森林边缘(m)。我们得出结论，田纳西林莺占据了城郊景观中有森林的中途停留点，在那里它们成功地换毛，然后继续迁徙。这项研究说明了在保护计划中包括中途停留点的重要性，特别是在高质量栖息地稀缺的城市。
{"title":"Moult migrant Tennessee Warblers undergo extensive stopover in peri-urban forests of southern Quebec","authors":"Vanessa Poirier, Barbara Frei, Mathilde Lefvert, Ana Morales, Kyle Hamish Elliott","doi":"10.1139/cjz-2023-0109","DOIUrl":"https://doi.org/10.1139/cjz-2023-0109","url":null,"abstract":"Stopovers are the most energy- and time-consuming events during avian migration, yet individuals of certain species make long stopovers to moult (‘moult migration’). Requiring abundant energy and a prolonged stay, moult migrants should occupy small stopover home ranges in resource-rich habitats. Understanding migrant behaviour at their stopovers is critical for implementing conservation efforts for declining Neotropical passerines. To examine the stopover timing and habitat use of one such moult migrating passerine, we radio-tagged 18 moulting and 4 post-moult Tennessee Warblers (Leiothlypis peregrina A. Wilson, 1811) at an autumn stopover site. Although our data were biased towards one sampling year, moult migrants generally arrived at the stopover site earlier (average = 2 August) than post-moult migrants (average = 12 September). Moult migrants also stayed longer (46 ± 5 days) than post-moult migrants (8 ± 6 days) and had large overlapping stopover home ranges (~15 ha) that were dependent on high abundance of forest (%) and forest edge (m). We conclude that Tennessee Warblers occupied forested stopover sites within a peri-urban landscape where they successfully moulted before continuing migration. This study illustrates the importance of including stopover sites in conservation plans, particularly in cities where quality habitats are scarce.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135728937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jason Thomas Fisher, Melanie Dickie, Joanna Burgar, Cole Burton, Robert D Serrouya
Density estimation is a key goal in ecology, but accurate estimates for unmarked animals remain elusive. Camera-trap data can bridge this gap, but accuracy, precision, and concordance varies among estimators. We compared estimates from unmarked spatial capture-recapture (spatial count, SC) models, and Time In Front of Camera (TIFC) models, for four large mammal species in boreal Canada. Species differed in movement rates, behaviours, and sociality – traits related to model assumptions. TIFC densities typically exceeded SC model estimates for all species. Two- to five-fold differences between estimators were common. SC estimates were annually stable for moose and caribou, but not for white-tailed deer. TIFC estimates showed high annual variation in some species, sites, and years, and consistency in others. Both models often produced imprecise estimates. Estimates varied from DNA- and aerial survey-based estimates. We contend models diverge, or implausibly vary, due to violations of model assumptions incurred by animal behavior. Gregarious animals pose challenges to SC whereas curious animals pose challenges for TIFC models. Simulations can help unravel the role of assumption violations in affecting accuracy of estimates, but field applications across species and landscapes help interpret the outcomes of estimating density from simulated data.
{"title":"Density estimates of unmarked mammals: Comparing two models and assumptions across multiple species and years.","authors":"Jason Thomas Fisher, Melanie Dickie, Joanna Burgar, Cole Burton, Robert D Serrouya","doi":"10.1139/cjz-2023-0055","DOIUrl":"https://doi.org/10.1139/cjz-2023-0055","url":null,"abstract":"Density estimation is a key goal in ecology, but accurate estimates for unmarked animals remain elusive. Camera-trap data can bridge this gap, but accuracy, precision, and concordance varies among estimators. We compared estimates from unmarked spatial capture-recapture (spatial count, SC) models, and Time In Front of Camera (TIFC) models, for four large mammal species in boreal Canada. Species differed in movement rates, behaviours, and sociality – traits related to model assumptions. TIFC densities typically exceeded SC model estimates for all species. Two- to five-fold differences between estimators were common. SC estimates were annually stable for moose and caribou, but not for white-tailed deer. TIFC estimates showed high annual variation in some species, sites, and years, and consistency in others. Both models often produced imprecise estimates. Estimates varied from DNA- and aerial survey-based estimates. We contend models diverge, or implausibly vary, due to violations of model assumptions incurred by animal behavior. Gregarious animals pose challenges to SC whereas curious animals pose challenges for TIFC models. Simulations can help unravel the role of assumption violations in affecting accuracy of estimates, but field applications across species and landscapes help interpret the outcomes of estimating density from simulated data.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135729344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luísa de Paula Reis, Jessica Fratani, María Laura Ponssa
Many species of anurans display special mechanical abilities, such as excavation and climbing. The aim of this study is to investigate the development of traits that are associated with these special mechanical abilities, under the hypothesis that these structures attain their configuration during the juvenile stages of development. We examined specimens from four different species of Leptodactylidae and six species of Hylidae. For the digging behavior, we evaluated the progress of calcification in the anterior region of the skulls, as well as the development of the snout-ridge. To assess climbing ability, we examined the ossification rate, the variation in the shape of the phalanx, the progress of the offset angle, and the distance between the terminal phalanx and the penultimate phalange of finger IV. The ossification of the skull and phalanges, along with the development of the snout-ridge, progresses and reaches completion during the juvenile phase of ontogeny, suggesting that at the time of metamorphosis, individuals are not yet full-scale replicas of the adults. The shape and the mechanical characteristics of terminal phalanges are already established by the conclusion of metamorphosis, revealing intriguing distinctions among arboreal species with walking and jumping locomotion.
{"title":"Are juveniles full-scale replicas of adults? Evaluation of anuran special locomotion and digging adaptations during and after metamorphosis","authors":"Luísa de Paula Reis, Jessica Fratani, María Laura Ponssa","doi":"10.1139/cjz-2023-0077","DOIUrl":"https://doi.org/10.1139/cjz-2023-0077","url":null,"abstract":"Many species of anurans display special mechanical abilities, such as excavation and climbing. The aim of this study is to investigate the development of traits that are associated with these special mechanical abilities, under the hypothesis that these structures attain their configuration during the juvenile stages of development. We examined specimens from four different species of Leptodactylidae and six species of Hylidae. For the digging behavior, we evaluated the progress of calcification in the anterior region of the skulls, as well as the development of the snout-ridge. To assess climbing ability, we examined the ossification rate, the variation in the shape of the phalanx, the progress of the offset angle, and the distance between the terminal phalanx and the penultimate phalange of finger IV. The ossification of the skull and phalanges, along with the development of the snout-ridge, progresses and reaches completion during the juvenile phase of ontogeny, suggesting that at the time of metamorphosis, individuals are not yet full-scale replicas of the adults. The shape and the mechanical characteristics of terminal phalanges are already established by the conclusion of metamorphosis, revealing intriguing distinctions among arboreal species with walking and jumping locomotion.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135480887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nematode communities in natural pristine forests composed of trees aged over a thousand years have not been thoroughly studied. Old-growth forests can provide diverse microhabitats for nematodes such as fallen trees with mossy conditions. This study aimed to characterize the community and trophic compositions of nematodes in relation to different microhabitats in old-growth Japanese cedar (Cryptomeria japonica (Lf) D.Don) forests in Yakushima Island, Japan. To this aim, nematodes retrieved from four different types of microhabitats were morphologically identified at the family/genus level and divided into five trophic groups. A non-metric multidimensional scaling scatterplot showed that nematode communities clustered significantly in each microhabitat and their community compositions were significantly affected by C/N ratio. With respect to nematode trophic composition, bacterivorous nematodes dominated decaying barks of fallen trees, with a relative abundance of 45%, while fungivorous nematodes were dominant in living barks of cedar trunks (61%). Predatory-omnivorous nematodes predominated in mosses of fallen trees (51%). These results showed that nematode community and trophic composition were different among microhabitats characterized by nutrient conditions. The predatory-omnivorous nematodes were abundant in mosses with N-rich conditions. In contrast, fungivorous nematodes were abundant in cedar trunks with high C/N conditions. Thus, old-growth natural forests can provide diverse microhabitats where various nematode taxa coexist due to the presence of fallen trees and mosses.
{"title":"Distribution and characterization of nematodes in above-ground microhabitats on a natural pristine cedar forest in Yakushima Island, Japan","authors":"Yudai Kitagami, Yosuke Matsuda","doi":"10.1139/cjz-2023-0107","DOIUrl":"https://doi.org/10.1139/cjz-2023-0107","url":null,"abstract":"Nematode communities in natural pristine forests composed of trees aged over a thousand years have not been thoroughly studied. Old-growth forests can provide diverse microhabitats for nematodes such as fallen trees with mossy conditions. This study aimed to characterize the community and trophic compositions of nematodes in relation to different microhabitats in old-growth Japanese cedar (Cryptomeria japonica (Lf) D.Don) forests in Yakushima Island, Japan. To this aim, nematodes retrieved from four different types of microhabitats were morphologically identified at the family/genus level and divided into five trophic groups. A non-metric multidimensional scaling scatterplot showed that nematode communities clustered significantly in each microhabitat and their community compositions were significantly affected by C/N ratio. With respect to nematode trophic composition, bacterivorous nematodes dominated decaying barks of fallen trees, with a relative abundance of 45%, while fungivorous nematodes were dominant in living barks of cedar trunks (61%). Predatory-omnivorous nematodes predominated in mosses of fallen trees (51%). These results showed that nematode community and trophic composition were different among microhabitats characterized by nutrient conditions. The predatory-omnivorous nematodes were abundant in mosses with N-rich conditions. In contrast, fungivorous nematodes were abundant in cedar trunks with high C/N conditions. Thus, old-growth natural forests can provide diverse microhabitats where various nematode taxa coexist due to the presence of fallen trees and mosses.","PeriodicalId":9484,"journal":{"name":"Canadian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135549011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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