Historic deforestation and non‐native plant invasions determine vegetation trajectories across an oceanic archipelago

Applied Vegetation Science, Год журнала: 2024, Номер 27(1)

Опубликована: Янв. 1, 2024

Abstract Questions Oceanic islands are global hotspots of endemism and evolutionary radiations but many have been severely degraded by human activities biological invasions. We evaluated the pace direction natural recovery ecosystems over 77 years across a subtropical oceanic archipelago including various size, elevation, histories settlement deforestation, invasions non‐native plants mammals. This information is essential to guide ecological restoration archipelago. Location Forest vegetation on nine Ogasawara Islands in northwestern Pacific Ocean. Methods first digitized historical data collected during field surveys 1935. Then, after checking their species compositions, we integrated past present plant community types. Finally, identified landscape‐scale changes forest comparing maps from 1935, 1979 2012. Results Over years, trajectories each island varied depending introduction invasive alien remaining proportion native forest, latter which had strong influence recoverability forest. Conclusions Our results highlight importance history introductions forest—both reflect intensity anthropogenic disturbance—in determining degree intervention needed for islands.

Язык: Английский

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Five-Year Evaluation of Sentinel-2 Cloud-Free Mosaic Generation Under Varied Cloud Cover Conditions in Hawai’i

Remote Sensing, Год журнала: 2024, Номер 16(24), С. 4791 - 4791

Опубликована: Дек. 22, 2024

The generation of cloud-free satellite mosaics is essential for a range remote sensing applications, including land use mapping, ecosystem monitoring, and resource management. This study focuses on across the climatic diversity Hawai’i Island, which encompasses ten Köppen climate zones from tropical to Arctic: periglacial. presents unique challenges image generation. We conducted comparative analysis three cloud-masking methods: two Google Earth Engine algorithms (CloudScore+ s2cloudless) new proprietary deep learning-based algorithm (L3) applied Sentinel-2 imagery. These methods were evaluated against best monthly composite selected high-frequency Planet imagery, acquires daily images. All bands enhanced 10 m resolution, an advanced weather mask was generate 2019 2023. stratified by cloud cover frequency (low, moderate, high, very high), applying one-way two-way ANOVAs assess pixel success rates. Results indicate that CloudScore+ achieved highest rate at 89.4% pixels, followed L3 s2cloudless 79.3% 80.8%, respectively. Cloud removal effectiveness decreased as increased, with clear rates ranging 94.6% under low high cover. Additionally, seasonality effects showed higher in wet season (88.6%), while no significant year-to-year differences observed advances current methodologies generating reliable subtropical regions, potential applications other cloud-dense environments.

Язык: Английский

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Ecological importance of the Myrtaceae in New Zealand's natural forests

Journal of Vegetation Science, Год журнала: 2021, Номер 33(1)

Опубликована: Дек. 21, 2021

Abstract Aims The Myrtaceae is a woody family that plays an important role in forest ecosystems globally. recent spread of myrtle rust, caused by fungal pathogen ( Austropuccinia psidii ), from its native South America into New Zealand (NZ), highlights the need to quantify ecological importance NZ ecosystems. Location Zealand. Methods Using nationwide and shrubland inventory data, collected 2009 2014, we quantified based on richness abundance relative co‐occurring families. We then explored how climate stand structure affect general tribe growth form. Finally, compared functional traits associated with plant reproductive strategies other dominant families determined Myrtaceae's contributions community‐weighted mean (CWM) trait values. Results occurred 74% study plots value was second highest across It only one which climbers substantially contributed (17%). Greater values were warmer more mesic climates early successional stages. Climate associations similar within tribes forms, whereas effects varied. functionally distinct most Contributions CWM wood density, maximum height, specific leaf area significantly greater than expected value. Conclusions ecologically has distinctive spectrum high density tall stature, ensuring large enduring carbon stocks. There will potentially be deleterious outcomes if taxon‐specific pathogens, such as , reduce importance.

Язык: Английский

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Mechanisms underlying interaction frequencies and robustness in a novel seed dispersal network: lessons for restoration

Proceedings of the Royal Society B Biological Sciences, Год журнала: 2022, Номер 289(1982)

Опубликована: Сен. 13, 2022

As human-caused extinctions and invasions accumulate across the planet, understanding processes governing ecological functions mediated by species interactions, anticipating effect of loss on such become increasingly urgent. In seed dispersal networks, mechanisms that influence interaction frequencies may also capacity a to switch alternative partners (rewiring), influencing network robustness. Studying interactions in novel ecosystems O'ahu island, Hawai'i, we test whether same defining can regulate rewiring increase robustness simulated extinctions. We found spatial temporal overlaps were primary underlying frequencies, more connected affected networks greater extent. Further, increased robustness, morphological matching between influential than abundances. argue achieve self-sustaining ecosystems, restoration initiatives consider optimal consumers resources maximize chances native plant dispersal. Specifically, benefit from replacing invasive with possessing characteristics promote frequent probability (such as long fruiting periods, small seeds broad distributions).

Язык: Английский

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A Near Four-Decade Time Series Shows the Hawaiian Islands Have Been Browning Since the 1980s

Environmental Management, Год журнала: 2022, Номер 71(5), С. 965 - 980

Опубликована: Ноя. 22, 2022

The Hawaiian Islands have been identified as a global biodiversity hotspot. We examine the Normalized Difference Vegetation Index (NDVI) using Climate Data Records products (0.05 × 0.05°) to identify significant differences in NDVI between neutral El Niño-Southern Oscillation years (1984, 2019) and long-term changes over entire time series (1982-2019) for six land cover classes. Overall, there has decline (i.e., browning) across from 1982 2019 with islands of Lāna'i Hawai'i experiencing greatest decreases (≥44%). All classes significantly decreased most months, especially during wet season month March. Native vegetation all also experienced declines NDVI, leeward, southwestern side island declines. trends annual total precipitation mean Palmer Drought Severity (PDSI) 1982-2019 on show concurrent Primarily positive correlations native ecosystem imply that may exacerbate decrease ecosystems. NDVI-PDSI were primarily negative windward leeward sides, suggesting higher sensitivity drought Multi-decadal spatially explicit data landscapes provide natural resource managers monthly associated health stability.

Язык: Английский

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What follows fallow? Assessing revegetation patterns on abandoned sugarcane land in Hawaiʻi

Agriculture Ecosystems & Environment, Год журнала: 2023, Номер 355, С. 108603 - 108603

Опубликована: Май 26, 2023

Millions of hectares agricultural land have been abandoned globally in recent decades, presenting opportunities for secondary vegetation growth and restoration. While fields the potential to return ecological communities with similar species diversity their pre-agricultural state, they alternatively may transition novel ecosystems or persist degraded states that alternative functions impact human communities. Yet we lack an understanding how naturally recovers on disturbed lands. Using remote sensing survey data, characterized structure, composition, function canopies former sugarcane Hawaiʻi were between 4 117 years ago. We used a distribution model identify patches uncultivated environmental conditions serve as reference ecosystems. these ecosystems, evaluated at different ages since abandonment compare terms canopy function. Grasses prevalent immediately following abandonment, but shrubs trees dominated structure had more than 20 years. Non-native constituted most vegetation, native cover increased longer 25 Secondary recovered functional traits ≤ 53 abandonment. Completely recovering structural properties would require over century. Abandoned are unlikely recover composition through unassisted recovery. Our findings contribute growing body literature characterizes whether when increasing area passively recover, which can direct restoration efforts lands enhance ecosystem services guide management achieve socio-cultural objectives.

Язык: Английский

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Strawberry guava invasion of a Hawaiian rainforest: Changing population patterns

Biotropica, Год журнала: 2024, Номер 56(4)

Опубликована: Апрель 18, 2024

Abstract Strawberry guava (waiawī, Psidium cattleyanum Sabine, Myrtaceae) is a small tree invasive on oceanic islands where it may alter forest ecosystem processes and community structure. To better understand the dynamics of its invasion in Hawaiian rainforests anticipation release biocontrol agent, we measured growth abundance vertical stems ≥0.5 cm DBH for 16 years (2005–2020) Metrosideros‐Cibotium rainforest windward Hawai'i Island. Specifically, compared both shoots (originating from seed or root mat) sprouts above ground established stems) four replicate study sites. Mean stem density increased 9562 stems/ha 2005 to 26,595 2020, majority which were <2 DBH. Early invasion, per capita recruitment was greater than that sprouts, but as overall increased, sprout came surpass shoots. Relative rates among declined over time relative consistently after first 3 years. The capacity strawberry recruit facilitates rainforest, persistence understory, response canopy opening. thus poses considerable risk stand replacement rainforests. Stand management will require perpetual efforts control production sprouting.

Язык: Английский

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Endemic island plant–herbivore interactions: Kamehameha butterfly (Nymphalidae) and Hawaiian Urticaceae

Biotropica, Год журнала: 2024, Номер unknown

Опубликована: Янв. 8, 2024

Abstract Insect–plant interactions are less well studied than other types of herbivory on islands, precluding a comprehensive understanding the evolutionary ecology these interactions. Declines in native island plants and insects call for urgent attention to characterize species' their conservation better understand evolution unique, insular ecosystems. In Hawai‘i, Kamehameha butterfly ( Vanessa tameamea ) is one only two butterflies, larvae specialists urticaceous plants. Using no‐choice bioassay, we investigated performance V . reared from egg hatching through eclosion four host plants, Boehmeria grandis , Pipturus albidus Touchardia latifolia oahuensis exotic species, Cecropia obtusifolia Performance varied significantly among plant diets, with performing best P T metrics survival, pupal adult body mass, development time. Larval responses C populations, O‘ahu caterpillars successfully completing it, but Hawai‘i Island rejecting it completely, suggesting geographic mosaic this novel species interaction. Characterization suite nutritive defensive traits revealed significant variability patterns did not align rankings, making difficult identify key drivers quality. Future work examining additional under natural conditions would provide new insights, contributing critical ecological information conserve charismatic species.

Язык: Английский

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Shifting paradigms and creating space for Indigenous leadership in biosecurity management and decision‐making

Conservation Biology, Год журнала: 2024, Номер 38(6)

Опубликована: Ноя. 25, 2024

Abstract In New Zealand, awareness regarding protection, enhancement, and regeneration of landscapes biodiversity is growing as the relationship between functioning diverse ecosystems society's health acknowledged. This especially important for Indigenous people, who hold strong genealogical familial ties with nature. Significant loss from anthropogenic factors exacerbated by climate change, ecosystem degradation, invasive species. Invasive species other biological threats, such native pathogens, are concerning Māori communities, cultural responsibilities to care Despite acknowledgment value perspectives in environmental management Zealand globally, participation still largely occurs within Western non‐Indigenous paradigms. We highlight biosecurity propose a shift Western‐based paradigms that reflect worldviews relationships place. Recognizing including elevates voices level decision‐making leadership lands. Given natural world intertwining their well‐being place (land) nature, threats also pose serious risks community well‐being. A holistic approach needed encompasses cultural, social, economic, at multiple scales. examined context relative plants proposed paradigm toward place‐based management. Biosecurity science science‐based tools remain an component, underscoring complementary aspects (Indigenous) culture.

Язык: Английский

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Agroforestry in a changing climate: Challenges, opportunities and solutions

Deleted Journal, Год журнала: 2024, Номер unknown

Опубликована: Дек. 1, 2024

Язык: Английский

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