Scientists’ warning – The outstanding biodiversity of islands is in peril

Global Ecology and Conservation, Journal Year: 2021, Volume and Issue: 31, P. e01847 - e01847

Published: Sept. 28, 2021

Despite islands contributing only 6.7% of land surface area, they harbor ~20% the Earth’s biodiversity, but unfortunately also ~50% threatened species and 75% known extinctions since European expansion around globe. Due to their geological geographic history characteristics, act simultaneously as cradles evolutionary diversity museums formerly widespread lineages—elements that permit achieve an outstanding endemicity. Nevertheless, majority these endemic are inherently vulnerable due genetic demographic factors linked with way colonized. Here, we stress great variation in physical geography (area, isolation, altitude, latitude) (age, human colonization, density). We provide examples some most rich iconic insular radiations. Next, analyze natural vulnerability biota, a result founder events well typically small population sizes many island species. note that, whereas evolution toward syndromes (including size shifts, derived woodiness, altered dispersal ability, loss defense traits, reduction clutch size) might have improved ability thrive under conditions on islands, it has made biota disproportionately anthropogenic pressures such habitat loss, overexploitation, invasive species, climate change. This led documented extinction at least 800 past 500 years, addition had already gone extinct following arrival first colonists prehistoric times. Finally, summarize current scientific knowledge ongoing biodiversity worldwide express our serious concern trajectory will continue decimate unique irreplaceable heritage world’s islands. conclude drastic actions urgently needed bend curve alarming rates loss.

Language: Английский

---

Island plant functional syndromes and competition with invasive species

Journal of Biogeography, Journal Year: 2023, Volume and Issue: 50(4), P. 641 - 653

Published: Jan. 27, 2023

Abstract Island floras are diverse with exceptionally high rates of endemicity, and they also severely threatened. Invasive plants widespread on islands, but whether islands particularly susceptible to invasion or island species more vulnerable displacement, both, remains unclear. As part the “island plant syndrome,” it has been predicted that have convergently evolved conservative resource use, slow growth rates, weak competitive abilities in response moderate climates presumed absence competition communities relatively low richness. Yet, functional trait approaches provided mixed evidence support this prediction, direct tests as neighbour effects performance lacking. Considering extensive environmental heterogeneity exists within among seems likely strategies, spanning acquisitive, plants. Furthermore, assessing syndrome predictions through comparisons invasive species, which nonrandom subsets continental plants, is a flawed approach. Future studies compare strategies native versus for between local scale at occurs, consider non‐additivities other simultaneous global threats, urgently needed conserve these biodiversity hotspots.

Language: Английский

---

Scale-dependent responses to environmental fluctuations in tropical tree species’ crown temperatures

Communications Earth & Environment, Journal Year: 2025, Volume and Issue: 6(1)

Published: Jan. 18, 2025

Abstract Tropical forests may be nearing critical temperatures, yet tree species respond differently. Using high-resolution thermal, hyperspectral, and LiDAR imagery, we mapped 652 crowns of four Hawaiian to study the effects crown traits abiotic conditions on species’ temperatures at two scales (whole vs. sunlit leaves). We show scale-dependent, species-specific relationships with environmental fluctuations. Net radiation was consistently dominant determinant temperature deviations from air (Tdiff), while vapor pressure deficit, wind speed, (e.g., roughness) varied in importance by scale. Species explained 17% 44% Tdiff variation leaf scales, respectively, after controlling for climatic factors. Findings suggest that overestimate larger-scale differences, canopy-scale observations underestimate heat stress. Because can have opposing Tdiff, disentangling these advance our understanding thermoregulation under climate change.

Language: Английский

---

Breeding system and pollination of Dubautia menziesii (Asteraceae), a self-incompatible Hawaiian alpine shrub

Flora, Journal Year: 2025, Volume and Issue: unknown, P. 152683 - 152683

Published: Feb. 1, 2025

Language: Английский

---

Diversity responses to precipitation gradients differ between older and younger islands of Hawai‘i

Frontiers of Biogeography, Journal Year: 2025, Volume and Issue: 18

Published: Feb. 28, 2025

Studying the interaction between macroevolutionary and ecological factors is critical for understanding principles of diversity regulation predicting effects human activities. Here, we use geological chronology Hawaiian archipelago as a testbed to examine island age climatic (i.e., precipitation) on contemporary patterns tree taxonomic diversity. To this end, estimated species from 375 forest plots spread across steep precipitation gradients different substrate ages younger (Hawai‘i; ~ 0.5 million years old), an intermediate-aged (Maui Nui complex; 2 older (O‘ahu; 3 old). We found clear positive relationship oldest (O‘ahu), but no such two islands (islands in Maui complex Hawai‘i). also high turnover drier wetter environments island, which suggests specialization these habitat types, not islands. However, when included that were highly invaded by alien species, effect varied had larger This could be because may more vulnerable invasions. Our results suggest response climate variation differs substantially Islands, possibly differences islands; however, biological invasions are degrading signature. Local responses gradient stronger likely due longer timescales processes. Species distinct conditions varies archipelago, with exhibiting greater precipitation-driven specialization. Alien alter local precipitation, particularly youngest archipelago. The presence modifying pattern conditions, dry mesic habitats intermediate-age showing higher turnover. Biological currently reshaping plant

Language: Английский

---

Scale‐dependent variation in leaf functional traits clarifies mechanisms of invasion

Ecography, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Comparing the functional traits of co‐occurring native and invasive plant species can offer insight regarding mechanisms invasion. Previous studies have failed to reach a consensus, indicating that extent trait differences between invasives might depend on environmental context spatial grain analysis. Here we evaluate scale‐dependency native–invader comparisons within Hawaiian Archipelago, globally important region high endemicity invasibility. We evaluated (e.g. gas exchange, leaf nutrient concentration, specific area) locally regionally (i.e. across islands) found while are more resource acquisitive at regional scale, highly idiosyncratic localized scales, varying both in direction magnitude islands. Our findings clarify how region‐wide may fail characterize interactions happening local thereby misleading or obscuring underlying

Language: Английский

---

Conservation applications of niche modeling: Native and naturalized ferns may compete for limited Hawaiian dryland habitat

Applications in Plant Sciences, Journal Year: 2024, Volume and Issue: 12(3)

Published: May 1, 2024

Abstract Premise Competition from naturalized species and habitat loss are common threats to native biodiversity may act synergistically increase competition for decreasing availability. We use Hawaiian dryland ferns as a model the interactions between land‐use change in determining Methods used fine‐resolution climatic variables carefully curated occurrence data herbaria community science repositories estimate distributions of ferns. quantified degree which tend occupy areas suitable mapped remaining available given change. Results Of all species, Doryopteris angelica had lowest percentage occurrences its area while D. decora highest. However, spp. higher overlap, Pellaea ternifolia lower than expected by chance. decipiens proportions ( < 20%) covering habitat. Discussion Areas characterized shared environmental preferences decrease due human development fallowed agricultural lands. Our study demonstrates value place‐based application recently developed correlative ecological niche modeling approach conservation risk assessment rapidly changing urbanized island ecosystem.

Language: Английский

---

Non‐native invasive plants in tropical dry forests: a global review of presence, impacts, and management

Restoration Ecology, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 15, 2024

Tropical dry forests (TDF) are among the most‐threatened terrestrial ecosystems, experiencing ongoing conversion to agricultural fields, pasture, and human settlements. Human disturbances often precursors invasion of ecosystems by non‐native species, but research on patterns in tropical is sparse, there no comprehensive synthesis invasive species TDF. We conducted a review published scientific literature catalog synthesize information about plants TDF across globe, drawing out these ecosystems. found that 130 plant were documented as present TDF, only 25 mentioned three or more articles. Almost all more‐studied species—mostly pasture grasses, woody legumes, climbers—have been intentionally cultivated for ornamental purposes. Many native open‐canopy savanna forest edge habitats benefit from human‐altered disturbance regimes (burning, grazing, fuelwood timber harvesting) fragments within landscapes. Field studies show management approaches incorporating removal, plantings, reduction (e.g. ungulate fencing fire control) simultaneously most successful at reducing cover. However, have focused limited number India Hawaii. Global differences soils, natural regimes, historic current land use humans influence modern biogeographic feasibility restoration options.

Language: Английский

---

How invaded are Hawaiian forests? Non-native understory tree dominance signals potential canopy replacement

Landscape Ecology, Journal Year: 2023, Volume and Issue: 38(12), P. 3903 - 3923

Published: April 25, 2023

Language: Английский

---

Hawaiian Subalpine Plant Communities: Implications of Climate Change

Pacific Science, Journal Year: 2024, Volume and Issue: 77(2-3)

Published: Feb. 1, 2024

Globally, subalpine and alpine plant communities are receiving increasing attention owing to disproportionately rapid warming at high altitudes, the resultant habitat shrinkage leaving high-altitude specialists with nowhere migrate. The Hawaiian zone (1,700–3,000 m) is an interesting example of this potential phenomenon because endemism. We analyzed species richness, cover, density from 89 plots (1,000 m2) sampled in 2010–2018 across two volcanic mountains, Haleakalā on Maui, Mauna Loa Hawai'i. Most 139 recorded were non-native (55%), remainder endemic (31%) indigenous (14%). Plot-level richness differed gamma diversity, more abundant than species. Non-native was higher Loa. These patchy low-lying (<1 vegetation, lower cover younger drier (36%) (54%). Density largely consistent understory data, Vaccinium reticulatum (>3,500/ha) Leptecophylla tameiameiae (>2,430/ha) shrubs dominant both volcanoes. Woodland encountered only Loa, trees Metrosideros polymorpha wetter, south aspects, Sophora chrysophylla drier, leeward side. vegetation varies among islands, volcanoes, yet remains native-dominated, though threats climate change, invasive species, wildfire. recommend continued monitoring biotic sensitive zone, situ physiological studies for native matrix stricter biosecurity sanitation protocols, wildfire prevention, improved documentation effects feral ungulates.

Language: Английский

---