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Browsing College of Natural Resources and Environment (CNRE) by Subject "07 Agricultural and Veterinary Sciences"
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- Contrasting long-term population trends of beach-nesting shorebirds under shared environmental pressuresKwon, Eunbi; Robinson, Samantha G.; Weithman, Chelsea E.; Catlin, Daniel H.; Karpanty, Sarah M.; Altman, Jon; Simons, Theodore R.; Fraser, James D. (Elsevier, 2021-08-01)Identifying the drivers of long-term population change is a key goal of ecological studies. It is complicated by extrinsic and intrinsic factors that may covary with time and/or operate on a time lag. For migratory shorebirds that breed on the barrier islands of eastern North America, populations may be limited by the anthropogenic, climatic, biological environments they encounter throughout the annual cycle. Using three-decades (1989–2017) of breeding monitoring data collected by the National Park Service at two national seashores in North Carolina (Hatteras and Lookout), we examined the potential drivers of nesting piping plover (Charadrius melodus) and American oystercatcher (Haematopus palliates) populations. Hatteras had five times more annual visitors than Lookout, and our modelling revealed a strong negative relationship between the population size of breeding plovers and human activity and a positive relationship with protection efforts aimed at reducing disturbance. Breeding and wintering climatic conditions, population productivity, and nesting habitat availability showed only weak effects. Thus, a decade-long decline in plover numbers at both seashores starting in the mid-90s reversed as the parks' visitor counts decreased and stricter protections from potential disturbance were implemented. However, the two sympatric populations of oystercatchers showed the opposite population trends from each other at the neighboring seashores, increasing only on Lookout after a hurricane improved habitat and subsequently the reproductive output. Our study suggests a strong relationship between the anthropogenic environment and the population trend of a threatened species and, simultaneously, the important role of stochastic events in shaping populations of long-lived shorebird species.
- Does a complex life cycle affect adaptation to environmental change? Genome-informed insights for characterizing selection across complex life cycleAlbecker, Molly A.; Wilkins, Laetitia G. E.; Krueger-Hadfield, Stacy A.; Bashevkin, Samuel M.; Hahn, Matthew W.; Hare, Matthew P.; Kindsvater, Holly K.; Sewell, Mary A.; Lotterhos, Katie E.; Reitzel, Adam M. (Royal Society, 2021-12-08)Complex life cycles, in which discrete life stages of the same organism differ in form or function and often occupy different ecological niches, are common in nature. Because stages share the same genome, selective effects on one stage may have cascading consequences through the entire life cycle. Theoretical and empirical studies have not yet generated clear predictions about how life cycle complexity will influence patterns of adaptation in response to rapidly changing environments or tested theoretical predictions for fitness trade-offs (or lack thereof) across life stages. We discuss complex life cycle evolution and outline three hypotheses—ontogenetic decoupling, antagonistic ontogenetic pleiotropy and synergistic ontogenetic pleiotropy—for how selection may operate on organisms with complex life cycles. We suggest a within-generation experimental design that promises significant insight into composite selection across life cycle stages. As part of this design, we conducted simulations to determine the power needed to detect selection across a life cycle using a population genetic framework. This analysis demonstrated that recently published studies reporting within-generation selection were underpowered to detect small allele frequency changes (approx. 0.1). The power analysis indicates challenging but attainable sampling requirements for many systems, though plants and marine invertebrates with high fecundity are excellent systems for exploring how organisms with complex life cycles may adapt to climate change.
- Impacts of rural to urban migration, urbanization, and generational change on consumption of wild animals in the AmazonChaves, Willandia A.; Valle, Denis; Tavares, Aline S.; Morcatty, Thais Q.; Wilcove, David S. (Wiley, 2020-10-30)For the first time in history, more people live in urban areas than in rural areas. This trend is likely to continue, driven largely by rural-urban migration. We investigated how rural-urban migration, combined with urbanization and generational change, affects consumption of wild animals, using one of the most hunted taxa in the Amazon: chelonians (tortoises and freshwater turtles). We surveyed 1,356 households and 2,776 schoolchildren across 10 urban areas of the Brazilian Amazon (six small towns, three large towns, and Manaus, the largest city in the Amazon Basin), using a Randomized Response Technique and anonymous questionnaires. Urban demand for wildmeat (i.e., meat from wildlife) was alarmingly high, with conservative estimates of approximately 1.7 million turtles and tortoises being consumed annually in Amazonas state. However, consumption rates declined with urban area size and between generations (adults versus children). Furthermore, the longer rural-urban migrants lived in urban areas, the lower their consumption rates were. These results suggest that wildlife consumption is a rural-related tradition that decreases with urbanization and over time after people move to urban areas. Current conservation efforts in the Amazon do not address urban demand for wildlife and may be insufficient to ensure the survival of traded species in the face of urbanization and human population growth. Our findings show that conservation interventions must target the urban demand for wildlife, especially by focusing on young people and recent rural-urban migrants.
- The importance of migratory connectivity for global ocean policyDunn, Daniel C.; Harrison, Autumn-Lynn; Curtice, Corrie; DeLand, Sarah; Donnelly, Ben; Fujioka, Ei; Heywood, Eleanor; Kot, Connie Y.; Poulin, Sarah; Whitten, Meredith; Akesson, Susanne; Alberini, Amalia; Appeltans, Ward; Manuel Arcos, Jos; Bailey, Helen; Ballance, Lisa T.; Block, Barbara A.; Blondin, Hannah; Boustany, Andre M.; Brenner, Jorge; Catry, Paulo; Cejudo, Daniel; Cleary, Jesse; Corkeron, Peter; Costa, Daniel P.; Coyne, Michael; Crespo, Guillermo Ortuno; Davies, Tammy E.; Dias, Maria P.; Douvere, Fanny; Ferretti, Francesco; Formia, Angela; Freestone, David; Friedlaender, Ari S.; Frisch-Nwakanma, Heidrun; Frojan, Christopher Barrio; Gjerde, Kristina M.; Glowka, Lyle; Godley, Brendan J.; Gonzalez-Solis, Jacob; Granadeiro, Jose Pedro; Gunn, Vikki; Hashimoto, Yuriko; Hawkes, Lucy M.; Hays, Graeme C.; Hazin, Carolina; Jimenez, Jorge; Johnson, David E.; Luschi, Paolo; Maxwell, Sara M.; McClellan, Catherine; Modest, Michelle; di Sciara, Giuseppe Notarbartolo; Palacio, Alejandro Herrero; Palacios, Daniel M.; Pauly, Andrea; Rayner, Matt; Rees, Alan F.; Salazar, Erick Ross; Secor, David; Sequeira, Ana MM M.; Spalding, Mark; Spina, Fernando; Van Parijs, Sofie; Wallace, Bryan; Varo-Cruz, Nuria; Virtue, Melanie; Weimerskirch, Henri; Wilson, Laurie; Woodward, Bill; Halpin, Patrick N. (Royal Society, 2019-09-18)The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.
- Long-term impacts of silvicultural treatments on wildland fuels and modeled fire behavior in the Ridge and Valley Province, Virginia (USA)Hahn, George E.; Coates, T. Adam; Aust, W. Michael; Bolding, M. Chad; Thomas-Van Gundy, Melissa A. (Elsevier, 2021-09-15)Active forest management operations, such as regeneration harvests, can reduce hazardous fuel loads and alter fuel structure, potentially minimizing extreme wildfire conditions while maintaining ecosystem services, such as wildlife habitat and water quality. Regeneration harvests of differing intensities (clearcut, high-retention shelterwood, and low-retention shelterwood) were first applied between 1995 and 1996 to three sites on the George Washington-Jefferson National Forest in the Ridge and Valley Province of Virginia, USA. Over two decades after the clearcut was conducted and 11–12 years after the overwood was removed in the shelterwood stands, woody debris, litter, and duff masses and depths were quantified. One-hour fuel loads were greater in clearcut units than in high-retention shelterwood, low-retention shelterwood, or control units. Ten-hour fuel loads were greater in clearcut and low-retention shelterwood units than in high-retention shelterwood and control units. No significant differences in 100-hour fuels were observed between treatments. Control units contained more rotten and total 1000-hour fuels than all other treatments. The total woody debris load was less in the clearcut and high-retention shelterwood than in the low-retention shelterwood and control. High-retention shelterwood woody fuel depth was greater than clearcut woody fuel depth. Litter and duff loads were less in treated units than in the control units. Total fuel load (woody fuel load + litter load + duff load) was greater in the control than the silvicultural treatments. Litter depth did not differ between treatments, while duff depth was greater in the control than in the treated units. Using the computer modeling software, BehavePlus 6.0.0, these alterations to fuel loads and depths led to increased values in the control units for six fire behavior parameters. Predicted surface flame length in the low-retention shelterwood was the only modeled value that was not less than control values. Overall, these results indicated that harvest intensity and timing may have long-term effects on down and dead woody fuels, forest floor depth, and potential fire behavior. Clearcutting reduced fire behavior most, followed by the high-retention shelterwood system. The potential differences in slash and debris generated by varying shelterwood systems may impact long-term fuel and fire dynamics.
- Predicting bark thickness with one- and two-stage regression models for three hardwood species in the southeastern USYang, Sheng-I; Radtke, Philip J. (Elsevier, 2022-01-01)Tree bark, as the outermost protective layer of tree stems, is an important indicator to evaluate the fire resistance properties of trees and to assess the tree mortality induced by fire. Despite its importance, many existing bark thickness models were not primarily developed for predicting bark thickness directly, i.e. with bark thickness as a response variable, and most past studies were focused on modeling bark thickness in conifers. Thus, the objective of this study was to compare the efficacy of various bark thickness models/methods for three common hardwood species in the southeastern US. A total number of 47,281 measurements from 2,070 trees were used in analysis. Results showed that bark thickness at breast height (1.37 m or 4.5 ft above ground) varies by tree size and species, which can be predicted by a species-specific linear regression model with DBH as a single predictor. To predict bark thickness profile, a combination of stem taper function and bark thickness model, a two-stage method, is suggested, which generally performs better than a single bark thickness function (one-stage method) in terms of bias and precision. For a given model form, the two-stage method produced more reliable prediction of bark thickness at upper and lower portions of tree stem than the one-stage method. With the three species examined, the segmented stem taper functions provided more accurate predictions than the variable-exponent function. The results of this study can provide guidance for ecologists and forest managers when selecting appropriate approaches to predict bark thickness.
- Testing a global standard for quantifying species recovery and assessing conservation impactGrace, Molly K.; Akcakaya, H. Resit; Bennett, Elizabeth L.; Brooks, Thomas M.; Heath, Anna; Hedges, Simon; Hilton-Taylor, Craig; Hoffmann, Michael; Hochkirch, Axel; Jenkins, Richard; Keith, David A.; Long, Barney; Mallon, David P.; Meijaard, Erik; Milner-Gulland, E. J.; Paul Rodriguez, Jon; Stephenson, P. J.; Stuart, Simon N.; Young, Richard P.; Acebes, Pablo; Alfaro-Shigueto, Joanna; Alvarez-Clare, Silvia; Andriantsimanarilafy, Raphali Rodlis; Arbetman, Marina; Azat, Claudio; Bacchetta, Gianluigi; Badola, Ruchi; Barcelos, Luis MD D.; Barreiros, Joao Pedro; Basak, Sayanti; Berger, Danielle J.; Bhattacharyya, Sabuj; Bino, Gilad; Borges, Paulo A.; Boughton, Raoul K.; Brockmann, H. Jane; Buckley, Hannah L.; Burfield, Ian J.; Burton, James; Camacho-Badani, Teresa; Santiago Cano-Alonso, Luis; Carmichael, Ruth H.; Carrero, Christina; P Carroll, John; Catsadorakis, Giorgos; Chapple, David G.; Chapron, Guillaume; Chowdhury, Gawsia Wahidunnessa; Claassens, Louw; Cogoni, Donatella; Constantine, Rochelle; Craig, Christie Anne; Cunningham, Andrew A.; Dahal, Nishma; Daltry, Jennifer C.; Das, Goura Chandra; Dasgupta, Niladri; Davey, Alexandra; Davies, Katharine; Develey, Pedro; Elangovan, Vanitha; Fairclough, David; Di Febbraro, Mirko; Fenu, Giuseppe; Fernandes, Fernando Moreira; Fernandez, Eduardo Pinheiro; Finucci, Brittany; Foldesi, Rita; Foley, Catherine M.; Ford, Matthew; Forstner, Michael RJ J.; Garcia, Nestor; Garcia-Sandoval, Ricardo; Gardner, Penny C.; Garibay-Orijel, Roberto; Gatan-Balbas, Marites; Gauto, Irene; Ghazi, Mirza Ghazanfar Ullah; Godfrey, Stephanie S.; Gollock, Matthew; Gonzalez, Benito A.; Grant, Tandora D.; Gray, Thomas; Gregory, Andrew J.; van Grunsven, Roy HA A.; Gryzenhout, Marieka; Guernsey, Noelle C.; Gupta, Garima; Hagen, Christian A.; Hagen, Christian A.; Hall, Madison B.; Hallerman, Eric M.; Hare, Kelly; Hart, Tom; Hartdegen, Ruston; Harvey-Brown, Yvette; Hatfield, Richard; Hawke, Tahneal; Hermes, Claudia; Hitchmough, Rod; Hoffmann, Pablo Melo; Howarth, Charlie; Hudson, Michael A.; Hussain, Syed Ainul; Huveneers, Charlie; Jacques, Helene; Jorgensen, Dennis; Katdare, Suyash; Katsis, Lydia KD D.; Kaul, Rahul; Kaunda-Arara, Boaz; Keith-Diagne, Lucy; Kraus, Daniel T.; de Lima, Thales Moreira; Lindeman, Ken; Linsky, Jean; Louis, Edward; Loy, Anna; Lughadha, Eimear Nic; Mangel, Jeffrey C.; Marinari, Paul E.; Martin, Gabriel M.; Martinelli, Gustavo; McGowan, Philip JK K.; McInnes, Alistair; Mendes, Eduardo Teles Barbosa; Millard, Michael J.; Mirande, Claire; Money, Daniel; Monks, Joanne M.; Laura Morales, Carolina; Mumu, Nazia Naoreen; Negrao, Raquel; Anh, Ha Nguyen; Niloy, Md Nazmul Hasan; Norbury, Grant Leslie; Nordmeyer, Cale; Norris, Darren; O'Brien, Mark; Oda, Gabriela Akemi; Orsenigo, Simone; Outerbridge, Mark Evan; Pasachnik, Stesha; Perez-Jimenez, Juan Carlos; Pike, Charlotte; Pilkington, Fred; Plumb, Glenn; Portela, Rita de Cassia Quitete D. C. Q.; Prohaska, Ana; Quintana, Manuel G.; Rakotondrasoa, Eddie Fanantenana; Ranglack, Dustin H.; Rankou, Hassan; Rawat, Ajay Prakash; Reardon, James Thomas; Rheingantz, Marcelo Lopes; Richter, Stephen C.; Rivers, Malin C.; Rogers, Luke Rollie; da Rosa, Patricia; Rose, Paul; Royer, Emily; Ryan, Catherine; de Mitcheson, Yvonne J. Sadovy; Salmon, Lily; Salvador, Carlos Henrique; Samways, Michael J.; Sanjuan, Tatiana; Dos Santos, Amanda Souza; Sasaki, Hiroshi; Schutz, Emmanuel; Scott, Heather Ann; Scott, Robert Michael; Serena, Fabrizio; Sharma, Surya P.; Shuey, John A.; Silva, Carlos Julio Polo; Simaika, John P.; Smith, David R.; Spaet, Julia LY Y.; Sultana, Shanjida; Talukdar, Bibhab Kumar; Tatayah, Vikash; Thomas, Philip; Tringali, Angela; Hoang, Trinh-Dinh; Tuboi, Chongpi; Usmani, Aftab Alam; Vasco-Palacios, Aida M.; Vie, Jean-Christophe; Virens, Jo; Walker, Alan; Wallace, Bryan; Waller, Lauren J.; Wang, Hongfeng; Wearn, Oliver R.; van Weerd, Merlijn; Weigmann, Simon; Willcox, Daniel; Woinarski, John; Yong, Jean WH H.; Young, Stuart (Wiley, 2021-07-21)Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a “Green List of Species” (now the IUCN Green Status of Species). A draft Green Status framework for assessing species’ progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species’ viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species’ recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard.