Jackson Helms - Academia.edu (original) (raw)

Papers by Jackson Helms

Ecology Letters, Feb 22, 2021

We utilise the wealth of data accessible through the 40-year-old Long-Term Ecological Research (L... more We utilise the wealth of data accessible through the 40-year-old Long-Term Ecological Research (LTER) network to ask if aspects of the study environment or taxa alter the duration of research necessary to detect consistent results. To do this, we use a moving-window algorithm. We limit our analysis to long-term (> 10 year) press experiments recording organismal abundance. We find that studies conducted in dynamic abiotic environments need longer periods of study to reach consistent results, as compared to those conducted in more moderated environments. Studies of plants were more often characterised by spurious results than those on animals. Nearly half of the studies we investigated required 10 years or longer to become consistent, where all significant trends agreed in direction, and four studies (of 100) required longer than 20 years. Here, we champion the importance of long-term data and bolster the value of multi-decadal experiments in understanding, explaining and predicting long-term trends.

Data associated with the paper "Ant biodiversity and ecosystem services in bioenergy landsca... more Data associated with the paper "Ant biodiversity and ecosystem services in bioenergy landscapes" by JA Helms, S Ijelu, BD Wills, DA Landis, and NM Haddad. Contains data about pitfall trap effort, ants collected in traps, and pest insect mortality across three bioenergy experiments at KBS LTER.

Forest and Society, Apr 26, 2020

Gunung Palung National Park in Indonesian Borneo, home to 2,500 Bornean orangutans (Pongo pygmaeu... more Gunung Palung National Park in Indonesian Borneo, home to 2,500 Bornean orangutans (Pongo pygmaeus ssp. wurmbii), suffers from severe deforestation that is caused by illegal logging. This article aims to analyze the success of an innovative entrepreneurship program in reducing illegal logging in Gunung Palung National Park. This program combines voluntary chainsaw buybacks with capital investment for former loggers to launch a business of their choice. To analyze the success of this entrepreneurship program, we measured two parameters: (1) transitions of former loggers to sustainable alternative livelihoods and (2) reductions in the number of loggers who log actively inside the park. The average monthly income for participating business partners was 2,923,333 rupiah or 209USDfornewpartnerswhohadparticipatedforlessthanoneyearand3,357,778rupiahor209 USD for new partners who had participated for less than one year and 3,357,778 rupiah or 209USDfornewpartnerswhohadparticipatedforlessthanoneyearand3,357,778rupiahor240 for established partners who had participated for more than one year. This income is about the minimum wage for the local area. The failure rate of the programdefined as the partners that returned to logging-was only 6%, or 3 out of 50 partners. Successful forest conservation, however, requires addressing additional factors beyond reducing the access to logging equipment.

Insectes Sociaux, Sep 12, 2016

Mercury contamination is a serious environmental concern usually associated with aquatic food web... more Mercury contamination is a serious environmental concern usually associated with aquatic food webs. We tested for the presence of mercury in winged queens and males of four ant species and found that invasive red imported fire ants (Solenopsis invicta) contain high levels of mercury typical of aquatic insects. Mercury concentrations in male fire ants were 51 % higher than those in females and 89–199 % higher than those in other ant species from the same location. Fire ant sexuals fly long distances on their mating flights and are a major food source for arthropod and vertebrate predators and may thus transfer mercury through food webs.

Biological Invasions, May 13, 2019

Dispersal in social parasites is constrained by the presence of suitable host populations, limiti... more Dispersal in social parasites is constrained by the presence of suitable host populations, limiting opportunities for rapid range expansion. For this reason, although hundreds of ant species have expanded their ranges through human transport, few obligate social parasites have done so. We test the hypothesis that social parasites expand their ranges more slowly than their hosts by examining the spread of an introduced social parasite-host species pair in North America-the workerless ant Tetramorium atratulum and the pavement ant T. immigrans. In doing so we report a new range extension of T. atratulum in the interior US. Consistent with host limitation on dispersal, we found a time lag ranging from several years to over a century between the arrivals of the host and parasite to a new region. The estimated maximum rate of range expansion in the parasite was only a third as fast as that of the host. We suggest that relative to free-living social insects, social parasites may be less able to rapidly shift their ranges in response to changes in habitat or climate.

Scientific Reports, Jun 29, 2016

IOP conference series, May 1, 2018

Gunung Palung National Park (1,080 km2, 1°3' – 1°22' S, 109°54' – 110°28' E) was ... more Gunung Palung National Park (1,080 km2, 1°3' – 1°22' S, 109°54' – 110°28' E) was first protected in 1937 and is now one of the largest remaining primary lowland mixed dipterocarp forests on Borneo. To help inform conservation efforts, we measured forest cover change in the protected area using 11 multi-temporal Landsat series images with path/row 121/61. Annual deforestation rates have declined since measurement began in 1989, to around 68 hectares per year in 2011 and 112 hectares per year in 2017. Halting deforestation in this protected area requires to tackle its underlying economic and social causes, and find ways for communities to meet their needs without resorting to forest clearing. Community empowerment, forest rehabilitation, and health care incentives as payment for ecosystem services can help reduce deforestation in Gunung Palung National Park. This becomes a positive trend which we must continue to always work in forest conservation. Future forest monitoring will be dependency with remote sensing analysis and open source remote sensing data such as Landsat and Sentinel data remain an important data source for historical forest change monitoring.

Tropical Conservation Science, 2018

The island of Borneo suffers from one of the highest deforestation rates in the world, primarily ... more The island of Borneo suffers from one of the highest deforestation rates in the world, primarily due to agriculture, logging, and other human activities. This habitat loss may be partly mitigated by reforestation programs in degraded landscapes, especially anthropogenic grasslands that have little conservation or economic value. By monitoring native bird communities, we evaluated the success of two small (<20 ha) community reforestation projects in Gunung Palung National Park in Indonesian Borneo. Birds responded rapidly following reforestation, with species richness doubling over 7 years at one site, and increasing by 29% in just 3 years at the other. Final tallies (63-70 species per site) were comparable to those obtained in older secondary forests elsewhere in Borneo. Anthropogenic fire is the primary threat to reforestation success, but intensive fire prevention allows bird communities to recover from temporary setbacks. Absence of fire was thus the most important factor in recovery, and we detected no effect of replanted area on bird species richness. Our results suggest that by engaging local communities and ensuring long-term maintenance, even small reforestation sites in Borneo can provide immediate benefits for native biodiversity.

Biology Letters, May 1, 2016

Aerial predator-prey interactions may impact populations of many terrestrial species. Here, we us... more Aerial predator-prey interactions may impact populations of many terrestrial species. Here, we use altitude loggers to study aerial foraging in a native insectivore, the purple martin (Progne subis), in the southern USA. Purple martins fed primarily on mating queens and males of the invasive red imported fire ant (Solenopsis invicta), and doubled their foraging efficiency by doing so. Across the USA, purple martins likely eat billions of fire ant queens each year, potentially impacting the spread of this species. Alternatively, predation on fire ants may help sustain populations of purple martins and other aerial insectivores.

Agriculture, Ecosystems & Environment, Mar 1, 2020

Most strategies for limiting global climate change invoke the use of bioenergy, but biofuel crops... more Most strategies for limiting global climate change invoke the use of bioenergy, but biofuel crops vary in climate mitigation potential and in the provision of other ecosystem services. The predominant biofuel in North America is ethanol produced from corn Zea mays. Corn is grown on ∼360,000 km 2 of land in the U.S. and ∼40 % of the yield is used for ethanol production. Despite its prevalence, corn ethanol is a poor climate change mitigator and the spread of intensive corn agriculture also leads to the loss of biodiversity and an unknown complement of associated ecosystem services. To test for effects of land use intensity on the provision of ecosystem services from biofuel crops, we compared insect communities inhabiting long-term experiments in which land use intensity varied from annual corn production to less intensive native perennial biofuel crops (switchgrass and restored prairie) and unmanaged native forests. Within the experiments we focused on ants (Formicidae: Hymenoptera), including their diversity, abundance, functional traits, and predation of biofuel crop pests. Native perennial biofuel crops supported up to 185 % more ant species than corn fields and provided up to 55 % more natural pest suppression. They also contained higher functional richness by supporting social parasites and seed dispersing ants that were absent in corn. Biofuel crops did not differ in ant activity or the prevalence of introduced ants. Our results highlight tradeoffs in bioenergy production and suggest ways to maximize benefits for wildlife and people. Converting some corn fields to prairie or other native vegetation could restore landscapes while mitigating climate change and meeting energy needs.

Insectes Sociaux, Nov 8, 2022

NeoBiota, Jan 27, 2017

Many species are expanding their ranges in response to climate changes or species introductions. ... more Many species are expanding their ranges in response to climate changes or species introductions. Expansion-related selection likely drives the evolution of dispersal and reproductive traits, especially in invasive species introduced into novel habitats. We used an agent-based model to investigate these relationships in the red imported fire ant, Solenopsis invicta, by tracking simulated populations over 25 years. Most colonies of this invasive species produce two types of queens practicing alternate reproductive strategies. Claustral queens found new colonies in vacant habitats, while parasitic queens take over existing colonies whose queens have died. We investigated how relative investment in the two queen types affects population demography, habitat occupancy, and range expansion. We found that parasitic queens extend the ecological lifespan of colonies, thereby increasing a population's overall habitat occupancy as well as average colony size (number of workers) and territory size. At the same time, investment in parasitic queens slowed the rate of range expansion by diverting investment from claustral queens. Divergent selection regimes caused edge and interior populations to evolve different levels of reproductive investment, such that interior populations invested heavily in parasitic queens whereas those at the edge invested almost entirely in claustral queens. Our results highlight factors shaping ant life histories, including the evolution of social parasitism, and have implications for the response of species to range shifts.

PLOS ONE, Apr 15, 2016

In the Found or Fly (FoF) hypothesis ant queens experience reproduction-dispersal tradeoffs such ... more In the Found or Fly (FoF) hypothesis ant queens experience reproduction-dispersal tradeoffs such that queens with heavier abdomens are better at founding colonies but are worse flyers. We tested predictions of FoF in two globally invasive fire ants, Solenopsis geminata (FABRICIUS, 1804) and S. invicta (BUREN, 1972). Colonies of these species may produce two different monogyne queen types-claustral queens with heavy abdomens that found colonies independently, and parasitic queens with small abdomens that enter conspecific nests. Claustral and parasitic queens were similarly sized, but the abdomens of claustral queens weighed twice as much as those of their parasitic counterparts. Their heavier abdomens adversely impacted morphological predictors of flight ability, resulting in 32-38% lower flight muscle ratios, 55-63% higher wing loading, and 32-33% higher abdomen drag. In lab experiments maximum flight durations in claustral S. invicta queens decreased by about 18 minutes for every milligram of abdomen mass. Combining our results into a simple fitness tradeoff model, we calculated that an average parasitic S. invicta queen could produce only 1/3 as many worker offspring as a claustral queen, but could fly 4 times as long and have a 17-to 36-fold larger potential colonization area. Investigations of dispersal polymorphisms and their associated tradeoffs promises to shed light on range expansions in invasive species, the evolution of alternative reproductive strategies, and the selective forces driving the recurrent evolution of parasitism in ants.

Authorea (Authorea), Nov 12, 2020

Long-term experiments are important in evaluating ecosystem properties and processes that are slo... more Long-term experiments are important in evaluating ecosystem properties and processes that are slow to develop or require proper evaluation over an appropriately variable climate. We repurpose the wealth of data accessible through the forty-year-old Long-Term Ecological Research (LTER) network with a novel moving window algorithm and meta-analysis approach to ask if aspects of study taxa or environment alter the extent of research necessary to detect consistent results, or the proportion of spurious short-term trends. We found that experimental studies focused on plants, and those conducted in dynamic abiotic environments, were characterized by longer critical temporal thresholds and more spurious trends. Further, nearly half of the studies we investigated required 10 years or longer to reach a temporal threshold, and 4 studies (of 100) required longer than 20 years. We champion long-term data and argue that long-term experiments are more necessary than ever to understand, explain, and predict long-term trends.

SPIE eBooks, Oct 1, 2013

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

provided additional technical and professional assistance. Mike Kaspari provided guidance on much... more provided additional technical and professional assistance. Mike Kaspari provided guidance on much of this work. Walter Tschinkel allowed me to use his field sites and assisted my work in Florida. OU Biological Station staff supported my work in southern Oklahoma.

Insectes Sociaux, Jul 29, 2014

Journal of Animal Ecology, Dec 21, 2020

This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as