Do Phytotoxic Compounds in Soils after Scale-infested Cycas micronesica Litter Deposits Explain Reduced Plant Growth?

Communicative & Integrative Biology

Dongol

2016

Self Cite

Leaf litter chemical traits were measured for Cycas micronesica plants in Guam following leaf herbivory by the scale Aulacaspis yasumatsui, the butterfly Chilades pandava caterpillar, or the leaf miner Erechthias sp. to determine the influence of the non-native pests on litter quality. Scale herbivory increased litter phenols above those of undamaged leaves but did not influence lignin or cellulose concentrations. Butterfly caterpillar herbivory increased litter phenols above and decreased litter lignin below those of undamaged leaves, but did not influence cellulose concentrations. Leaf miner herbivory increased litter lignin concentrations above those of undamaged leaves, but did not influence phenols or cellulose concentrations. Herbivory influenced 8 of 12 essential elements that were quantified. Herbivory by all 3 insects increased nitrogen and potassium litter concentrations and decreased calcium and iron litter concentrations when compared with undamaged litter. The responses were idiosyncratic among herbivores for the remaining essential elements. Stoichiometry among the chemical constituents indicated that herbivory increased litter quality and predicted more rapid biogeochemical cycling in Guam's ecosystems as a result of these 3 non-native insect invasions.

Section: Discussionmentioning

confidence: 66%

Three invasive insects alterCycas micronesicaleaf chemistry and predict changes in biogeochemical cycling

Communicative & Integrative Biology

Dongol

2016

Self Cite

“…This subset of the plant-soil feedback agenda is often invoked for discussing allelopathic properties that remain in soils following invasive plant species growth. For example, soils that persist following the widespread mortality of C. micronesica due to long-term A. yasumatsui damage often remain barren due to unidentified residuals [29,30].…”

Section: Plant-soil Feedbackmentioning

confidence: 99%

Cycas micronesica Trees Alter Local Soil Traits

Krishnapillai

2018

Forests

Cycad plants possess uncommon morphological, chemical, and ontogenetic characteristics and they may introduce localized changes in soil traits that increase habitat heterogeneity. We used mature Cycas micronesica K.D. Hill trees growing in a range of soil types in Guam, Rota, and Yap to quantify differences between the soils beneath target trees and paired non-target soils away from cycad trees. The chronic presence of a C. micronesica tree introduced numerous localized changes in soil traits, increasing the heterogeneity of elemental stoichiometry in the community. Nitrogen, carbon:phosphorus, and nitrogen:phosphorus were increased in target soils among every soil type. Carbon increased and phosphorus decreased in most target soils. The habitats revealing the greatest number of elements with differences between target and non-target soils were the habitats with acid soils. The greatest number of metals exhibiting differences between the target and non-target soils occurred in the impoverished sandy habitat. This is the first report that indicates a cycad tree increases community spatial heterogeneity by localized changes in soil chemistry. Contemporary declines in cycad populations due to anthropogenic threats inadvertently decrease this spatial heterogeneity and its influences on primary producers in the landscape then cascading effects on the food web.

“…Indeed, ecosystem changes can be misunderstood in insular settings if consistent monitoring is not used [50]. This wise approach of a funding agency enabled the accumulation of the only existing long-term C. micronesica survival data set throughout three islands and has resulted in numerous peer-reviewed articles that are available to inform future C. micronesica conservation decisions [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68].…”

Section: Success Is Available If Empowered Individuals Desire Itmentioning

confidence: 99%

Tree conservation can be constrained by agents from conservation permitting and funding agencies

Communicative & Integrative Biology

2019

Self Cite

Recent conservation actions for Serianthes nelsonii Merr. and Cycas micronesica K.D. Hill in the Mariana Islands have illuminated some negative consequences associated with ill-informed agents representing permitting and funding agencies. Several cases from the islands of Guam and Tinian are discussed as ineffective conservation examples, and these are countered with two examples of successful conservation approaches. When biologists that act as points of contact for federal permitting and funding agencies do not possess education, knowledge, and experience that is germane to federally listed species, sound science may be marginalized from the conservation agenda. When rapid turnover of federal conservation agents introduces dysfunction, discontinuities in collaborations may thwart success. When lapses in conservation contracts are allowed, short-term extemporary contracting approaches are utilized, and conservation practitioners that lack the ability to include an experimental approach to conservation actions are employed, the co-production of new knowledge to enable decision support tools for future decision-makers may be hindered.