This document is the first progress report of Amelia Lamb's research on the effects of shrubs and understory annual plants on kangaroo rat species in a desert annual community. The report summarizes previous literature on positive plant interactions and the stress gradient hypothesis. It also describes the study site and species, and outlines the methods for surveys to examine animal activity along a shrub and annual plant gradient, and foraging experiments using giving-up density trials to study kangaroo rat foraging patterns. Current objectives include further analyzing pilot study data, and carrying out extensive field surveys and experiments in April and May.
This study characterized baseline conditions in minimally impacted headwater streams in three major river drainages in southern West Virginia. Benthic macroinvertebrate samples were collected in the summer and fall of 2013 using a Hess sampler from sites in the New River, Guyandotte River, and Tug Fork drainages. The macroinvertebrates were identified to genus level and several biotic indices were calculated, including the WVSCI and GLIMPSS(CF), to assess stream health.
This document summarizes a study on the nesting behaviors of house crows in Penang, Malaysia. It found that house crows exhibit clumped nest distribution and prefer taller trees like Pterocarpus indicus with large diameters. Nests were often located high and correlated with tree height. The number of nests differed significantly between study locations but not across months from January to March. House crows also occasionally built solitary nests and reused or dismantled nests from year to year. The study provides insight into the nesting ecology and selection of house crows, an invasive bird species in Malaysia.
Developing a sampling plan for sugarcane aphid in sorghumJennifer Blackburn
This document discusses developing a sampling plan for sugarcane aphid in sorghum. There is currently no efficient, user-friendly sampling system to determine sugarcane aphid density and evaluate if treatment thresholds have been met. The authors and collaborators from multiple states aim to characterize the seasonal distribution of sugarcane aphid within sorghum fields and plants. They will develop sequential and binomial sampling protocols, validate the protocols using natural infestations, and create a decision-making tool for sugarcane aphid management. The work is funded by a USDA NIFA grant.
Wildlife conservancies and pastoral livelihoods in the Maasai Mara, KenyaILRI
Claire Bedelian conducted research on wildlife conservancies and pastoral livelihoods in the Maasai Mara, Kenya. She studied (1) how conservancy participation impacts income sources and wealth, and (2) how conservancies alter land use and grazing patterns. Her research found that conservancies contribute 14% of household income on average, rising to 21% for member households. However, after controlling for household characteristics, most wealth differences between member and non-member households disappeared. Analysis of satellite imagery showed that livestock enclosures decreased more inside conservancies between 2006-2011 compared to outside areas.
The Great Rivers Ecological Observatory Network (GREON) monitors water quality in the Upper Mississippi River Basin using floating monitoring platforms called Pontoons for In-Situ Characterization of Environmental Systems (PISCES). GREON's mission is to collect and share high resolution data on key water quality parameters like temperature, dissolved oxygen, nitrates and chlorophyll to advance understanding of large floodplain river ecology. Current sites include locations on the Mississippi, Missouri and Illinois Rivers. GREON collaborates with various partners and aims to expand its network of monitoring sites.
This document discusses the Australian Supersite Network, which establishes long-term intensive monitoring sites across representative ecosystems. Each Supersite includes buildings, instrumentation, scientists, and a 10-400km transect to study ecological gradients. Core activities include flux measurements, plant/soil studies, and faunal monitoring. The network aims to understand ecosystem stocks, fluxes, biodiversity dynamics, and responses to changes. Infrastructure includes flux towers, weather stations, and field stations. Key questions focus on current ecosystem exchanges, biodiversity patterns, and responses to disturbances. The plan is to engage scientists, states, and the wider community at each Supersite through open days and involvement in the expanding network.
This study examined the nesting patterns and movements of spectacled eiders on Kigigak Island in Alaska from 1998-2012. The researchers found that:
1) Nest success had a significant effect on dispersal distance between consecutive years, with unsuccessful nests dispersing farther on average than successful nests.
2) There was no significant variation found in average yearly dispersal distances between years.
3) Comparisons to a previous 1992-1997 study found differences in dispersal distances of unsuccessful nests, which the authors attributed to differences in sample sizes, data selection, and analysis methods between the studies.
This study characterized baseline conditions in minimally impacted headwater streams in three major river drainages in southern West Virginia. Benthic macroinvertebrate samples were collected in the summer and fall of 2013 using a Hess sampler from sites in the New River, Guyandotte River, and Tug Fork drainages. The macroinvertebrates were identified to genus level and several biotic indices were calculated, including the WVSCI and GLIMPSS(CF), to assess stream health.
This document summarizes a study on the nesting behaviors of house crows in Penang, Malaysia. It found that house crows exhibit clumped nest distribution and prefer taller trees like Pterocarpus indicus with large diameters. Nests were often located high and correlated with tree height. The number of nests differed significantly between study locations but not across months from January to March. House crows also occasionally built solitary nests and reused or dismantled nests from year to year. The study provides insight into the nesting ecology and selection of house crows, an invasive bird species in Malaysia.
Developing a sampling plan for sugarcane aphid in sorghumJennifer Blackburn
This document discusses developing a sampling plan for sugarcane aphid in sorghum. There is currently no efficient, user-friendly sampling system to determine sugarcane aphid density and evaluate if treatment thresholds have been met. The authors and collaborators from multiple states aim to characterize the seasonal distribution of sugarcane aphid within sorghum fields and plants. They will develop sequential and binomial sampling protocols, validate the protocols using natural infestations, and create a decision-making tool for sugarcane aphid management. The work is funded by a USDA NIFA grant.
Wildlife conservancies and pastoral livelihoods in the Maasai Mara, KenyaILRI
Claire Bedelian conducted research on wildlife conservancies and pastoral livelihoods in the Maasai Mara, Kenya. She studied (1) how conservancy participation impacts income sources and wealth, and (2) how conservancies alter land use and grazing patterns. Her research found that conservancies contribute 14% of household income on average, rising to 21% for member households. However, after controlling for household characteristics, most wealth differences between member and non-member households disappeared. Analysis of satellite imagery showed that livestock enclosures decreased more inside conservancies between 2006-2011 compared to outside areas.
The Great Rivers Ecological Observatory Network (GREON) monitors water quality in the Upper Mississippi River Basin using floating monitoring platforms called Pontoons for In-Situ Characterization of Environmental Systems (PISCES). GREON's mission is to collect and share high resolution data on key water quality parameters like temperature, dissolved oxygen, nitrates and chlorophyll to advance understanding of large floodplain river ecology. Current sites include locations on the Mississippi, Missouri and Illinois Rivers. GREON collaborates with various partners and aims to expand its network of monitoring sites.
This document discusses the Australian Supersite Network, which establishes long-term intensive monitoring sites across representative ecosystems. Each Supersite includes buildings, instrumentation, scientists, and a 10-400km transect to study ecological gradients. Core activities include flux measurements, plant/soil studies, and faunal monitoring. The network aims to understand ecosystem stocks, fluxes, biodiversity dynamics, and responses to changes. Infrastructure includes flux towers, weather stations, and field stations. Key questions focus on current ecosystem exchanges, biodiversity patterns, and responses to disturbances. The plan is to engage scientists, states, and the wider community at each Supersite through open days and involvement in the expanding network.
This study examined the nesting patterns and movements of spectacled eiders on Kigigak Island in Alaska from 1998-2012. The researchers found that:
1) Nest success had a significant effect on dispersal distance between consecutive years, with unsuccessful nests dispersing farther on average than successful nests.
2) There was no significant variation found in average yearly dispersal distances between years.
3) Comparisons to a previous 1992-1997 study found differences in dispersal distances of unsuccessful nests, which the authors attributed to differences in sample sizes, data selection, and analysis methods between the studies.
Opportunities to Practically Scale-up Perennial FeedstocksAmanda Bilek
Presented by Vance Owens, Director of North Central Sun Grant Center, South Dakota State University on December 8, 2014 at Minnesota Bioenergy Feedstock Development meeting and forum.
Predicting the Distribution of the Invasive Cactus Moth, Cactoblastis cactoru...Kristen Sauby
The document describes research on the distribution of the invasive cactus moth (Cactoblastis cactorum) and its host plant (Opuntia stricta) in Florida. Researchers surveyed over 1,300 plots using stratified random and adaptive cluster sampling. They found the invasive moth primarily on O. stricta and O. humifusa var. ammophila. Generalized linear mixed models showed O. stricta occurrence was positively related to detritus density and vegetation density. Models also showed invasive moth occurrence on O. stricta was positively related to host plant height and percent cover. The research provides insights into factors that structure the occurrence of the invasive moth and its cactus host in Florida.
This study used habitat suitability models at multiple spatial scales from 100-4000 meters to understand how 10 bat species in the Western Ghats region of India respond to different land uses, including tea and coffee plantations. The models found that most bat species showed a positive response to coffee plantations with native shade trees and forest fragments, but a negative response to more cleared tea plantations. Small-scale habitat variables like percentage tea plantation cover and distance to water were strongest predictors, likely due to bats' high mobility. While bats responded negatively to tea plantations overall, tea-dominated landscapes containing forest and shade coffee can still support many bat species.
This document provides an overview of a research project studying the effects of different grazing management strategies on carbon and nitrogen cycling in rangelands. The project compares a low stocking density grazing strategy to an ultra-high stocking density strategy. Key findings include greater vegetation trampling but similar litter deposition under high density grazing. The project also found higher dung beetle diversity under rotational grazing regardless of stocking density. Dung beetle activity did not significantly impact greenhouse gas fluxes or dung decomposition rates. Spatial and temporal patterns of dung distribution will be modeled to estimate ranch-level nutrient cycling under different management strategies.
-0.582367
0.29
2003-2007
0.136140
0.31
2008-2012
1992-1997 (1)
1998-2002 (2)
2003-2007 (3)
2008-2012 (4)
C
B
A
A
LS Mean
Std Err
-0.117533
0.27
B
2.427069
0.25
A
2.569744
0.24
A
3.591432
0.26
A
(2)
Msc. synopsis OAT Genetic diversity and molecular markersArushi Arora
This document outlines a proposed study on genetic diversity analysis in oat (Avena sativa) varieties using agro-morphological and molecular markers. The study will characterize 56 indigenous and exotic oat genotypes, along with 4 checks, using agro-morphological traits like flowering time, plant height, and yield components. Molecular characterization will be done using SSR markers to analyze diversity. Statistical analysis will include ANOVA, variability parameters, correlation, path analysis, genetic divergence, and principal component analysis. The research aims to assess genetic diversity in oat genotypes and identify varieties suitable for forage, seed yield, and related traits.
Longleaf Pine Ecosystems
Productivity and biodiversity patterns of a longleaf pine ecosystem.
Ecological forestry and restoration of longleaf pine ecosystems.
Ecological role of mesopredators, effects of control, and habitat approaches.
Aquatic Ecology and Water Resources
Hydrologic variation and human development in the lower Flint River Basin
Depressional wetlands on the coastal plain landscape: maintenance of regional biodiversity
This document summarizes a study on using cover crops to manage the root-knot nematode (Meloidogyne incognita) in yam production systems. Pot and field experiments tested the effect of 10 cover crops on M. incognita populations and yam tuber damage. Results showed that tagetes, crotalaria, and aeschynomene cover crops significantly reduced nematode densities and yam damage, while lablab, mucuna, and cowpea supported high nematode populations. The document concludes that tagetes, crotalaria, and aeschynomene should be incorporated into yam farming to control root-knot nematodes.
The Hudson Valley is a treasured landscape that has undergone tremendous change over the past century. This forum explores how science-based stewardship on private land can help protect and promote healthy forests and open spaces, now and for future generations.
Presentations explore threats our forests and natural areas face – from invasive species and climate change to deer overabundance – and actions that can be taken on a site-by-site basis to optimize conditions. A special focus will be given to the overlap between sport hunting and conservation communities, with a roundtable discussion on advancing common ground. Hosted April 12, 2014 at Cary Institute of Ecosystem Studies
Presentation Part IV by: Raymond Winchcombe, Wildlife Ecologist, Cary Institute of Ecosystem Studies
This study examined nest survival rates in experimentally created snags on a managed forest landscape from 2008-2010. Researchers monitored 506 nests of 8 bird species that nest in cavities. Overall nest success was 67%. Specifically, chestnut-backed chickadee nest success was 65% and house wren success was 78%. The study found that leaving created snags at a density of about 0.5 per hectare can retain some cavity-nesting bird species for up to 12-15 years, but the benefits are limited by the forest's rotation age and different strategies are needed to provide taller snag habitats.
This document outlines the steps and objectives for students to conduct a study of a selected ecosystem. The main activities involve noting the features of the ecosystem, identifying plants and animals using keys, conducting qualitative and quantitative surveys of organisms, examining how organisms are adapted to the environment, and constructing food chains, webs and pyramids to illustrate energy transfer. Students will study a minimum of 10 organisms, including 5 plants and 5 animals, and investigate the abiotic factors and adaptations that influence their distribution within the ecosystem.
This study examined the dispersal abilities, population structure, and performance of two Cape Xenopus frog species: X. gilli and X. laevis. The results show that X. laevis has greater jumping and swimming performance. X. laevis also dispersed farther and more frequently. Analysis of skeletal growth layers was not effective for aging Cape Xenopus. Survival rates of X. gilli were lower at sites where it co-occurred with X. laevis, suggesting a negative impact of X. laevis on X. gilli. The results provide evidence that X. laevis poses a threat to X. gilli through competition and potential hybridization.
Assessing Botanical and Pollinator Communities in ROW HabitatsLaurenWeyers
This document summarizes a study assessing the effects of integrated vegetation management (IVM) practices on pollinator and botanical communities in rights-of-way (ROW) habitats. The study involved butterfly, bee, and vegetation surveys along transects in ROWs to track biodiversity changes over three seasons. Results showed various pollinator groups including butterflies, bees, flies and beetles present in the ROWs. Milkweeds and nectar resources varied by season. Habitat composition was biased towards pollinator habitats. Future directions include increasing data resolution, using baseline data to track long-term changes, and emphasizing training to improve survey consistency. The study demonstrates that ROWs can provide valuable wildlife habitat when
The document discusses the morphological and behavioral adaptations of predatory mites that allow them to prey on spider mites. It describes the different life types of spider mites, including little web, complicated web, and web nest types. It also characterizes the life styles of various predatory mite species as specialists that can invade spider mite webs or generalists that forage outside of webs. Specialist predators like Phytoseiulus persimilis and Galendromus helveolus have adaptations like thread-cutting abilities that facilitate predation within spider mite webs. Understanding these life styles and adaptations can help select compatible predator-prey combinations for biological control of spider mites.
M.Sc. Detection Dog Handler Thesis. Fiona Jackson.Fiona Jackson
This document is a dissertation submitted for a Master's degree in animal welfare, ethics, and law. It includes a review paper and experimental paper examining the effect of the handler on the performance of trained detection dogs. The review paper analyzes literature on handler influence and bias, finding the handler-dog relationship is critical but research is lacking on how handlers may introduce biases. The experimental paper describes a study with 4 experienced handlers and 4 novice handlers running detection dog trials to analyze differences in performance and handler behaviors.
This document summarizes research on modifying crested wheatgrass stands to increase structural diversity. The research involved:
1) Seeding experiments at two sites in southern Idaho where crested wheatgrass was suppressed through mowing or herbicide and native grasses, forbs and shrubs were seeded.
2) Results showed reducing seed dispersal and herbicide applications improved establishment of seeded species, but mortality over time may require reseeding.
3) The research concludes that modifying crested wheatgrass stands to restore native diversity requires suppressing the wheatgrass to give seeded species a chance to establish.
This study examined potential mechanisms for fern species coexistence in Catlins forests of New Zealand. The study analyzed differences in environmental traits between sites characterized by different dominant tree types (gymnosperm or angiosperm), and differences in functional traits between common fern species. Results showed soil temperature varied significantly between sites, with higher temperatures under gymnosperm trees. However, other environmental traits did not differ between sites. Significant differences were found for several functional traits (specific leaf area, specific root length, pinnae thickness, water use efficiency) between fern species. This supports the hypothesis that functional trait diversity, rather than environmental heterogeneity, is the prevailing mechanism allowing coexistence of fern species in these forests.
This document summarizes organic farming research projects at the University of Nebraska. It discusses three main grants focused on improving organic farming systems across the state. The first grant aims to create certified organic research plots, improve production through research, and extend results to the public. The second grant supports developing wheat cultivars and cropping systems optimized for organic production. The third grant provides research on organic nutrient management, weed control methods, and their impact on biodiversity. Key areas of research discussed include cover crops, weed control through flaming, breeding wheat varieties for organic systems, and assessing biodiversity using the Healthy Farm Index. The document emphasizes developing partnerships with organic organizations and farmers to support the research.
Opportunities to Practically Scale-up Perennial FeedstocksAmanda Bilek
Presented by Vance Owens, Director of North Central Sun Grant Center, South Dakota State University on December 8, 2014 at Minnesota Bioenergy Feedstock Development meeting and forum.
Predicting the Distribution of the Invasive Cactus Moth, Cactoblastis cactoru...Kristen Sauby
The document describes research on the distribution of the invasive cactus moth (Cactoblastis cactorum) and its host plant (Opuntia stricta) in Florida. Researchers surveyed over 1,300 plots using stratified random and adaptive cluster sampling. They found the invasive moth primarily on O. stricta and O. humifusa var. ammophila. Generalized linear mixed models showed O. stricta occurrence was positively related to detritus density and vegetation density. Models also showed invasive moth occurrence on O. stricta was positively related to host plant height and percent cover. The research provides insights into factors that structure the occurrence of the invasive moth and its cactus host in Florida.
This study used habitat suitability models at multiple spatial scales from 100-4000 meters to understand how 10 bat species in the Western Ghats region of India respond to different land uses, including tea and coffee plantations. The models found that most bat species showed a positive response to coffee plantations with native shade trees and forest fragments, but a negative response to more cleared tea plantations. Small-scale habitat variables like percentage tea plantation cover and distance to water were strongest predictors, likely due to bats' high mobility. While bats responded negatively to tea plantations overall, tea-dominated landscapes containing forest and shade coffee can still support many bat species.
This document provides an overview of a research project studying the effects of different grazing management strategies on carbon and nitrogen cycling in rangelands. The project compares a low stocking density grazing strategy to an ultra-high stocking density strategy. Key findings include greater vegetation trampling but similar litter deposition under high density grazing. The project also found higher dung beetle diversity under rotational grazing regardless of stocking density. Dung beetle activity did not significantly impact greenhouse gas fluxes or dung decomposition rates. Spatial and temporal patterns of dung distribution will be modeled to estimate ranch-level nutrient cycling under different management strategies.
-0.582367
0.29
2003-2007
0.136140
0.31
2008-2012
1992-1997 (1)
1998-2002 (2)
2003-2007 (3)
2008-2012 (4)
C
B
A
A
LS Mean
Std Err
-0.117533
0.27
B
2.427069
0.25
A
2.569744
0.24
A
3.591432
0.26
A
(2)
Msc. synopsis OAT Genetic diversity and molecular markersArushi Arora
This document outlines a proposed study on genetic diversity analysis in oat (Avena sativa) varieties using agro-morphological and molecular markers. The study will characterize 56 indigenous and exotic oat genotypes, along with 4 checks, using agro-morphological traits like flowering time, plant height, and yield components. Molecular characterization will be done using SSR markers to analyze diversity. Statistical analysis will include ANOVA, variability parameters, correlation, path analysis, genetic divergence, and principal component analysis. The research aims to assess genetic diversity in oat genotypes and identify varieties suitable for forage, seed yield, and related traits.
Longleaf Pine Ecosystems
Productivity and biodiversity patterns of a longleaf pine ecosystem.
Ecological forestry and restoration of longleaf pine ecosystems.
Ecological role of mesopredators, effects of control, and habitat approaches.
Aquatic Ecology and Water Resources
Hydrologic variation and human development in the lower Flint River Basin
Depressional wetlands on the coastal plain landscape: maintenance of regional biodiversity
This document summarizes a study on using cover crops to manage the root-knot nematode (Meloidogyne incognita) in yam production systems. Pot and field experiments tested the effect of 10 cover crops on M. incognita populations and yam tuber damage. Results showed that tagetes, crotalaria, and aeschynomene cover crops significantly reduced nematode densities and yam damage, while lablab, mucuna, and cowpea supported high nematode populations. The document concludes that tagetes, crotalaria, and aeschynomene should be incorporated into yam farming to control root-knot nematodes.
The Hudson Valley is a treasured landscape that has undergone tremendous change over the past century. This forum explores how science-based stewardship on private land can help protect and promote healthy forests and open spaces, now and for future generations.
Presentations explore threats our forests and natural areas face – from invasive species and climate change to deer overabundance – and actions that can be taken on a site-by-site basis to optimize conditions. A special focus will be given to the overlap between sport hunting and conservation communities, with a roundtable discussion on advancing common ground. Hosted April 12, 2014 at Cary Institute of Ecosystem Studies
Presentation Part IV by: Raymond Winchcombe, Wildlife Ecologist, Cary Institute of Ecosystem Studies
This study examined nest survival rates in experimentally created snags on a managed forest landscape from 2008-2010. Researchers monitored 506 nests of 8 bird species that nest in cavities. Overall nest success was 67%. Specifically, chestnut-backed chickadee nest success was 65% and house wren success was 78%. The study found that leaving created snags at a density of about 0.5 per hectare can retain some cavity-nesting bird species for up to 12-15 years, but the benefits are limited by the forest's rotation age and different strategies are needed to provide taller snag habitats.
This document outlines the steps and objectives for students to conduct a study of a selected ecosystem. The main activities involve noting the features of the ecosystem, identifying plants and animals using keys, conducting qualitative and quantitative surveys of organisms, examining how organisms are adapted to the environment, and constructing food chains, webs and pyramids to illustrate energy transfer. Students will study a minimum of 10 organisms, including 5 plants and 5 animals, and investigate the abiotic factors and adaptations that influence their distribution within the ecosystem.
This study examined the dispersal abilities, population structure, and performance of two Cape Xenopus frog species: X. gilli and X. laevis. The results show that X. laevis has greater jumping and swimming performance. X. laevis also dispersed farther and more frequently. Analysis of skeletal growth layers was not effective for aging Cape Xenopus. Survival rates of X. gilli were lower at sites where it co-occurred with X. laevis, suggesting a negative impact of X. laevis on X. gilli. The results provide evidence that X. laevis poses a threat to X. gilli through competition and potential hybridization.
Assessing Botanical and Pollinator Communities in ROW HabitatsLaurenWeyers
This document summarizes a study assessing the effects of integrated vegetation management (IVM) practices on pollinator and botanical communities in rights-of-way (ROW) habitats. The study involved butterfly, bee, and vegetation surveys along transects in ROWs to track biodiversity changes over three seasons. Results showed various pollinator groups including butterflies, bees, flies and beetles present in the ROWs. Milkweeds and nectar resources varied by season. Habitat composition was biased towards pollinator habitats. Future directions include increasing data resolution, using baseline data to track long-term changes, and emphasizing training to improve survey consistency. The study demonstrates that ROWs can provide valuable wildlife habitat when
The document discusses the morphological and behavioral adaptations of predatory mites that allow them to prey on spider mites. It describes the different life types of spider mites, including little web, complicated web, and web nest types. It also characterizes the life styles of various predatory mite species as specialists that can invade spider mite webs or generalists that forage outside of webs. Specialist predators like Phytoseiulus persimilis and Galendromus helveolus have adaptations like thread-cutting abilities that facilitate predation within spider mite webs. Understanding these life styles and adaptations can help select compatible predator-prey combinations for biological control of spider mites.
M.Sc. Detection Dog Handler Thesis. Fiona Jackson.Fiona Jackson
This document is a dissertation submitted for a Master's degree in animal welfare, ethics, and law. It includes a review paper and experimental paper examining the effect of the handler on the performance of trained detection dogs. The review paper analyzes literature on handler influence and bias, finding the handler-dog relationship is critical but research is lacking on how handlers may introduce biases. The experimental paper describes a study with 4 experienced handlers and 4 novice handlers running detection dog trials to analyze differences in performance and handler behaviors.
This document summarizes research on modifying crested wheatgrass stands to increase structural diversity. The research involved:
1) Seeding experiments at two sites in southern Idaho where crested wheatgrass was suppressed through mowing or herbicide and native grasses, forbs and shrubs were seeded.
2) Results showed reducing seed dispersal and herbicide applications improved establishment of seeded species, but mortality over time may require reseeding.
3) The research concludes that modifying crested wheatgrass stands to restore native diversity requires suppressing the wheatgrass to give seeded species a chance to establish.
This study examined potential mechanisms for fern species coexistence in Catlins forests of New Zealand. The study analyzed differences in environmental traits between sites characterized by different dominant tree types (gymnosperm or angiosperm), and differences in functional traits between common fern species. Results showed soil temperature varied significantly between sites, with higher temperatures under gymnosperm trees. However, other environmental traits did not differ between sites. Significant differences were found for several functional traits (specific leaf area, specific root length, pinnae thickness, water use efficiency) between fern species. This supports the hypothesis that functional trait diversity, rather than environmental heterogeneity, is the prevailing mechanism allowing coexistence of fern species in these forests.
This document summarizes organic farming research projects at the University of Nebraska. It discusses three main grants focused on improving organic farming systems across the state. The first grant aims to create certified organic research plots, improve production through research, and extend results to the public. The second grant supports developing wheat cultivars and cropping systems optimized for organic production. The third grant provides research on organic nutrient management, weed control methods, and their impact on biodiversity. Key areas of research discussed include cover crops, weed control through flaming, breeding wheat varieties for organic systems, and assessing biodiversity using the Healthy Farm Index. The document emphasizes developing partnerships with organic organizations and farmers to support the research.
1. Amelia Lamb
1st Progress Report
March 19th 2013
Shrub and understory annual plant
effects on resident kangaroo rat
species in a desert annual
community
2. Introduction
Facilitation in plant communities
MacIntire and Fajardo 2014; Pugnaire et al. 2011; Soliveres et al. 2011; Holmgren and Scheffer 2010; Brooker et al. 2008; Bruno et al.
2003; Holmgren et al. 1997; Callaway and Walker 1997; Pugnaire et al. 1996.
3. Introduction
The Stress Gradient Hypothesis (SGH)
Michelet et al. 2013; Holmgren 2010; Malkinson 2010; Maestre et al. 2009; Brooker et al. 2008; Kawai et al. 2007; Lortie and Callaway
2006; Maestre et al. 2006; Callaway and Walker 1994.
4. Introduction
Armas and Pugnaire 2005; Gomez-Aparicio et al. 2004; Flores and Jurado 2003; Holzapfel 1999; Pugnaire et al . 1996; Callaway
1995.
Nurse Plants
11. Survey
• Purpose: examine the
impact of shrubs and
annuals on animal
activity along a
gradient
• 5-point gradient- sites
differ by 200 meters
• Microsites- shrub vs.
open
• Replicates- 100
pairs/sub-site
• Treatments-annuals
removed (50 pairs)
annuals intact (50
pairs)
Chapter 2
14. Kangaroo rat foraging patterns and GUD
Chapter 3
• Purpose: examine the
impact of shrubs and
annuals on foraging
patterns and GUD
• 5-point gradient: sites
differ by 200 meters
• Microsites: shrub vs.
open
• # of Trials: 10-15
• Replicates:
3/treatment/sub-site
(60 trays)
• Treatments: annuals
removed; annuals intact
15. Methods
• Trays: reinforced aluminum foil; sifted sand; millet seed
• Shrub side: positioned under north side near base and adjacent
open area
• Set up: before sunset; flatten surface; set up cameras; collect
trays/cameras before sunrise; record activity; sieve contents; weigh
remaining seeds
• Pilot study: krats ate seeds; cameras recorded krat activity.
Chapter 3
16. Current Objectives
• Lab
• Finish extracting systematic review data
• Begin writing review
• Finish analyzing data from pilot survey and GUD trials
• Field (April 15th – May 30th)
• Extensive survey of Larrea tridentata and associated annual vegetation and
animal activity (at least 100 paired shrub/open site per elevational sub-site)
• 10-15 GUD trials; 4 treatments; 3 replicates per treatment in each
elevational sub-site (60 trays/trial)
Facilitative, or positive interactions that benefit at least one participant and cause harm to neither,have been described from plant communities around the globe. Although the study of negative interactions such as competition has dominated the literature in the past, in the last 2 decades facilitation has been recognized as an important driving force in plant community assembly. Positive plant-plant interactions can occur when one plant makes the microenvironment more favorable for another plant either directly (by regulating temperature, moisture or nutrient stress) or indirectly by eliminating competing plant species or deterring predators (Bruno et al. 2003).
The bulk of evidence for facilitative effects between plants comes from severe environments, such as deserts, arctic or alpine systems, tundra systems, or salt marshes (Brooker et al. 2008). Bertness and Callaways seminal 1994 paper proposed that increases in the degree of abiotic stress would increase the frequency of positive interactions, so understanding the balance of positive and negative interactions can be best understood by comparing them along gradients of abiotic stress.
Nurse plants are often the focus of studies of facilitation. A nurse plant is one that benefits other plant species through mechanisms such as stress amelioration, herbivore protection, and substrate modification (Callaway 1995). Many examples of plant-based facilitation come from arid and semi-arid environments where dominant desert shrubs facilitate annual species that ordinarily would not be able to grow there. This photo illustrates the nurse plant effect quite well…you can see here a mat of green annual vegetation underneath this desert shrub while annual vegetation is nearly absent from adjacent open areas.
Nesting plant-animal interactions into known plant-plant interaction networks is rare. Positive plant-plant interactions are an important current topic and provide a great opportunity to explore the extended importance of these facilitative interactions to other taxa. For plant-animal interactions, especially those nested within positive plant-plant interaction networks, variation in abiotic conditions is likely very important. So, it’s important that these studies also incorporate gradients to examine whether the sign, strength, or frequency of interactions is dependent on variation or ‘stress’ within the environment. Chapters 2 and 3 of my thesis project involve testing aspects of this interaction.
For the first chapter of my thesis I will be conducting a systematic review regarding the positive impacts of shrubs on animals to identify any areas or mechanisms that have been extensively studied as well as any possible research gaps. There are no reviews that I am aware of that specifically target positive shrub-animal interactions. I am only including those papers testing positive effects of shrubs focusing on the animal side of the interaction. I searched the web of knowledge database using the search terms shrub* and animal* limiting the search to relevant research areas. The resulting 844 articles were exported into Microsoft Excel and reviewed for inclusion criteria resulting 122 retained articles. Data extracted from each article includes the type of interaction (direct/indirect); nature of interaction; evidence of any reciprocal interactions; the shrub and animal species examined; climate data; and GPS coordinates. To identify the geographic distribution of these studies GPS coordinates were extracted from each article. Work for this systematic review is ongoing. I have to finish extracting data and I will be adding additional search terms to ensure I have identified all of the relevant research on the topic to date.
Here is a map of the geographic distribution of those studies. Although the studies are widespread around the globe the bulk of the studies have been conducted in North America especially in the mid-west and south-west United States as well as in eastern Europe. Currently I am finishing extracting all other relevant data from these studies.
Field work for chapters 2 and 3 of my project will take place within the Mojave National Preserve which is located in the Mojave Desert of San Bernardino County, California.
My field site is located along Kelbaker Road, a 56 mile paved road that runs through the reserve. The vegetation in this area is dominated by the creosote shrub Larrea tridentata, and to a lesser extent Ambrosia dumosa(Pavlik 1989; Beatley 1974). Yucca brevifolia (the Joshua tree)also makes up a large portion of the vegetation at higher elevations (Brooks and Matchett 2006). The dominant shrub Larrea tridentataand it’s effects on resident kangaroo rats will be the focus of this research.
The genus Dipodomys is a group commonly referred to as kangaroo rats due to their bipedal locomotion. They are nocturnal, burrowing rodents of the family Heteromyidae, endemic to western North America. They are primarily granivorous (store seeds in cheek pouches) but will occasional consume vegetation. Krats have been shown to be important components of desert ecosystems directly through soil disturbance (burrow creation increases soil nitrogen and moisture levels by mixing surface soils with subsurface soils) and indirectly through preferential seed selection (select seeds based on size and moisture content which leads to the promotion of some species and possible suppression of others). These animals may be reciprocally impacting resident shrub and annual plants, so a better understanding of their use of shrubs is important in understanding the ecology of the system. 3 kangaroo rat species are found in the Mojave National Preserve: Dipodomys deserti (the desert kangaroo rat), Dipodomys Merriami(Merriam’s kangaroo rat), and Dipodomys microps (the chisel-toothed kangaroo rat) (The IUCN Red List of Threatened Species).
The 2nd chapter of my project will consist of an extensive survey of kangaroo rat activity and annual vegetation in shrub and open microsites along an elevational gradient (located on Kelbaker rd) to examine the relative impact of desert shrubs and desert annuals on kangaroo rat activity and how differences in elevation effects these interactions. The study site will be broken up into 5 sub-sites that differ in elevation by approximately 200 meters. I hope to survey at least 100 shrub/open pairs per elevational sub-site. In order to assess the relative important of shrubs vs. annuals on animal activity I will be removing all annuals from 50 shrub/open pairs per elevational subsite. Animal measurements include counting scat, burrows, tracks, trails, and determining total disturbance. Shrub dimensions and annual measurements such as the number of annual species, % cover, and the number of individuals will also be recorded as well as environmental measures such as elevation, temperature, and humidity.
Animal measurements include counting scat, burrows, tracks, trails, and determining total disturbance. Shrub dimensions and annual measurements such as the number of annual species, % cover, and the number of individuals will also be recorded as well as environmental measures such as elevation, temperature, and humidity.
I conducted a pilot survey in January of this year. I surveyed 125 shrub/open microsites along the elevational gradient. Although I haven’t finished analyzing the data the difference in the number of burrows between the two microsites really stood out to me, so I ran a t-test to see if the means of the shrub/open microsites differed significantly, and as you can see for the shrubs I surveyed there are significantly more burrows located in shrub microsites in comparison to open microsites (t=-13.59; p<0.001).
Chapter 3 of my study will involve an experiment testing the effect of Larrea tridentata and associated annual vegetation on the foraging patterns and giving up densities of kangaroo rats along an elevational gradient. The giving up density method (Brown 1988) predicts that a forager will stop depleting a patch when the cost of foraging outweigh the benefits of foraging at a particular patch. The giving up density is the density or mass of a resource remaining after a set amount of time. For this experiment within each elevational sub-site there will be 4 treatments: shrub with annuals intact; open with annuals intact; shrub with annuals removed; and open with annuals removed.
Seed trays will be constructed using reinforced aluminum foil trays, sifted sand, and a known mass of unhusked millet seeds (4 grams). The seeds will be mixed with the sand and the surface will be flattened to facilitate the identification and counting of kangaroo rat tracks and other signs of activity (scat; digging). Seed trays will be positioned under the north side of each shrub approximately 20-40 cm from the base and 1-1.5 meters from shrub edge in adjacent open area. The trays will be set up shortly before sunset and left out until just before sunrise. 10 motion triggered wildlife cameras will also be used during this experiment to help examine foraging patterns and to help with species identification. Before sunrise trays and cameras will be collected and the contents of the trays will be sieved in order to calculate the remaining seed mass.