We conducted a long‐term experiment in grassland with the aim of elucidating grassland dynamics in relation to variations in rainfall amount and spatial and temporal variation in disturbance. In particular we aimed to increase our understanding of ecosystem dynamics and function, species redundancy, invasion biology, and other related topics. We studied the dynamics of serpentine annual grassland in northern California over the period 1983–2002 in a replicated series of experimental plots comprising controls, gopher exclosures, and aboveground herbivore exclosures. Annual rainfall amount varied greatly during the study period, which included two major El Niño events and a period of prolonged below‐average rainfall. Gopher disturbance was highly variable both spatially and temporally but was positively correlated with soil depth. Disturbance was reduced but not eliminated from the gopher exclosures and was significantly increased in the aboveground herbivore exclosures. Grassland dynamics were driven by rainfall amounts and distributions that had the most pronounced effects on the dominant plant species, while gopher disturbance had additional effects on the rarer species. Effects of excluding aboveground herbivores were swamped by a large increase in gopher disturbance within aboveground exclosures. Overall species numbers were reduced during a period of below‐average rainfall but recovered in subsequent years. There was a large array of different responses of individual plant species to both rainfall and disturbance. Our results provide support for the “insurance” hypothesis, which suggests that biodiversity buffers ecosystem processes against environmental changes because different species (or phenotypes) respond differently to these changes, leading to functional compensations among species. Here, a species that was at very low abundance levels at the start of the study (Microseris douglasii) temporarily increased in abundance to become one of the dominant species in the grassland following a period of prolonged below‐average rainfall. We also observed the repeated invasion of the serpentine grassland by the nonnative grass Bromus hordeaceus, which increased greatly in abundance following both of the major El Niño events. The results emphasize the importance of long‐term observations in providing a context for shorter‐term studies and allowing analysis of plant community responses to climate variation and disturbance, particularly in the face of ongoing global change.
Māori and Pacific peoples with dementia presented to an NZ memory service at a younger age than NZ Europeans, and Pacific peoples presented with more advanced dementia. A population-based epidemiological study is critical to determine whether Māori and Pacific peoples have indeed a higher risk of developing dementia at a younger age.
Background As the economic impact of dementia on health and social care increases, governments require disease‐specific epidemiological data that will help inform spending and policy decisions. The aim of this study is to examine predictors of mortality in dementia in consecutive referrals to a New Zealand (NZ) memory service that includes Māori, Pacific Islander, and NZ European patients. Methods Date of birth, sex, ethnicity, living situation, cognitive function, dementia subtype, dementia severity, physical comorbidity, and medication data were collected from electronic health records. The resulting data set was linked to administrative data on mortality and last hospital contact dates to allow time‐dependent survival analyses. Results The risk of death in people with dementia was increased by age (adjusted HR per year 1.08, 95%CI:1.05‐1.12) and lower cognitive score at baseline (adjusted HR for severe impairment:2.54, 95% CI:1.25‐5.16), and was reduced by cholinesterase inhibitors (adjusted HR:0.54, 95% CI:0.34‐0.88). Compared to NZ Europeans (HR:1.19, 95% CI:0.63‐2.25), antipsychotics increased the risk of death three‐fold in Māori (adjusted HR:3.62, 95% CI:0.79‐16.7) and Pacific Islanders (adjusted HR:2.54, 95%CI:1.10‐5.85). Conclusions Further research is required to elucidate the mechanisms underlying the survival rates in Māori and Pacific Islanders living with dementia in NZ,and their increased risk of death if antipsychotics are used.
Currently, there are estimated to be 70,000 people living with dementia in Aotearoa, New Zealand (NZ). This figure is projected to more than double by 2040, but due to the more rapid growth of older age groups in non-European populations, prevalence will at least triple amongst the NZ Indian population. The impact of dementia in the NZ Indian community is currently unknown. The aim of this study was to explore the lived experiences of NZ Indians living with dementia and their caregivers. Ten caregivers (age range: 41–81) and five people living with mild dementia (age range: 65–77) were recruited from a hospital memory service and two not-for-profit community organisations in Auckland, Aotearoa, NZ. Semi-structured interviews were conducted by bilingual/bicultural researchers and transcribed for thematic analysis in the original languages. Dementia was predominantly thought of as being part of normal ageing. Getting a timely diagnosis was reported as difficult, with long waiting times. Cultural practices and religion played a large part in how both the diagnosis and ongoing care were managed. Caregivers expressed concerns about societal stigma and about managing their own health issues, but the majority also expressed a sense of duty in caring for their loved ones. Services were generally well-received, but gaps were identified in the provision of culturally appropriate services. Future health services should prioritise a timely diagnosis, and dementia care services should consider specific cultural needs to maximise uptake and benefit for Indian families living with dementia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.