36 results on '"Giam, X"'
Search Results
2. Estimating How Many Undescribed Species Have Gone Extinct
- Author
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TEDESCO, P. A., BIGORNE, R., BOGAN, A. E., GIAM, X., JÉZÉQUEL, C., and HUGUENY, B.
- Published
- 2014
3. Quantifying the relative performance of two undetected-extinction models
- Author
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Lum, D., Tedesco, Pablo, Hugueny, Bernard, Giam, X. L., and Chisholm, R. A.
- Subjects
biodiversity loss ,model comparison ,conservation ,social sciences ,simulations ,humanities ,description curve - Abstract
Extinctions of undiscovered species (undetected extinctions) constitute a portion of biodiversity loss that is often ignored. We compared the performance of 2 models of undetected extinctions - Tedesco and SEUX - when estimating undetected extinctions with both simulated and real-world data. We generated simulated data by considering a birth-death process in which less abundant species were more likely to go extinct. When detection rates were higher for common species, the 2 models underestimated the true number of undetected extinctions by up to 88.7%, and when detection rates were independent of abundance, the 2 models performed better; the SEUX model had an average bias of +3.1% and the Tedesco model had an average bias of -62.3%. We applied the models to 8 real-world data sets (e.g., Australian amphibians, Australian birds, North American bivalves) and found that true extinctions may be from 15% to 180% higher than observed values. For 6 of the 8 data sets, the SEUX model yielded absolute estimates that were 5.7-66.8% lower than those of the Tedesco model. We mainly attributed this difference to the SEUX model's assumption that there are no undetected extant species currently. We assessed the accuracy of the models' estimates with a logistic regression to test whether detection and extinction rates were uncorrelated across species. Rates were correlated for 3 of the 8 data sets; species discovered later had a higher probability of being extinct, suggesting that extinction numbers could be even higher for these groups. Despite caveats associated with the models, the evidence from both show biodiversity loss in these groups may be more severe than what has been documented.
- Published
- 2020
4. Testing the diversity-biomass relationship in riverine fish communities
- Author
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Woods, T., Comte, L., Tedesco, Pablo, and Giam, X.
- Subjects
biomass ,path analysis ,niche partitioning ,functional traits ,non-native species ,species richness ,streams - Abstract
Aim We examined the diversity-biomass relationship in stream fish communities and quantified direct and indirect effects of abiotic variables on this relationship. Location France. Time period 1992-2012. Major taxa studied Stream fishes. Methods We analysed the relationship between biodiversity (species richness and functional diversity) and fish community biomass at 1,357 stream sites distributed throughout France. We used piecewise path analysis to quantify effects of abiotic and biodiversity variables on biomass and assess relative contributions of native and non-native species on the diversity-biomass relationship. Results Biodiversity showed a direct positive relationship with biomass after controlling for sampling effort, and direct effects of biodiversity variables on community biomass exceeded those of climate and physical habitat variables. Our analysis indicates that positive effects of species richness on biomass exceeded those of functional diversity. Indirect effects of abiotic variables mediated by biodiversity metrics indicated that biomass increased in warmer, lowland habitats. Human impact had no effect on native biodiversity but had a positive effect on non-native biodiversity. Main conclusions We provide evidence that direct effects of biodiversity on community biomass outweigh those of abiotic variables in riverine fish communities, but resource partitioning alone is unlikely to drive the effects of biodiversity on biomass in this system. Quantification of the relative roles of anthropogenic impacts, biodiversity and environmental context in the regulation of ecosystem functioning will be necessary to understand the potential consequences of ongoing global change.
- Published
- 2020
5. Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences
- Author
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Wijedasa, LS, Jauhiainen, J, Kononen, M, Lampela, M, Vasander, H, Leblanc, MC, Evers, S, Smith, TEL, Yule, CM, Varkkey, H, Lupascu, M, Parish, F, Singleton, I, Clements, GR, Aziz, SA, Harrison, ME, Cheyne, S, Anshari, GZ, Meijaard, E, Goldstein, JE, Waldron, S, Hergoualc'h, K, Dommain, R, Frolking, S, Evans, CD, Posa, MRC, Glaser, PH, Suryadiputra, N, Lubis, R, Santika, T, Padfield, R, Kurnianto, S, Hadisiswoyo, P, Lim, TW, Page, SE, Gauci, V, Van der Meer, PJ, Buckland, H, Garnier, F, Samuel, MK, Choo, LNLK, O'Reilly, P, Warren, M, Suksuwan, S, Sumarga, E, Jain, A, Laurance, WF, Couwenberg, J, Joosten, H, Vernimmen, R, Hooijer, A, Malins, C, Cochrane, MA, Perumal, B, Siegert, F, Peh, KSH, Corneau, LP, Verchot, L, Harvey, CF, Cobb, A, Jaafar, Z, Wosten, H, Manuri, S, Muller, M, Giesen, W, Phelps, J, Yong, DL, Silvius, M, Wedeux, BMM, Hoyt, A, Osaki, M, Hirano, T, Takahashi, H, Kohyama, TS, Haraguchi, A, Nugroho, NP, Coomes, DA, Quoi, LP, Dohong, A, Gunawan, H, Gaveau, DLA, Langner, A, Lim, FKS, Edwards, DP, Giam, X, Van der Werf, G, Carmenta, R, Verwer, CC, Gibson, L, Grandois, L, Graham, LLB, Regalino, J, Wich, SA, Rieley, J, Kettridge, N, Brown, C, Pirard, R, Moore, S, Capilla, BR, Ballhorn, U, Ho, HC, Hoscilo, A, Lohberger, S, Evans, TA, Yulianti, N, Blackham, G, Onrizal, Husson, S, Murdiyarso, D, Pangala, S, Cole, LES, Tacconi, L, Segah, H, Tonoto, P, Lee, JSH, Schmilewski, G, Wulffraat, S, Putra, EI, Cattau, ME, Clymo, RS, Morrison, R, Mujahid, A, Miettinen, J, Liew, SC, Valpola, S, Wilson, D, D'Arcy, L, Gerding, M, Sundari, S, Thornton, SA, Kalisz, B, Chapman, SJ, Su, ASM, Basuki, I, Itoh, M, Traeholt, C, Sloan, S, Sayok, AK, Andersen, R, Wijedasa, LS, Jauhiainen, J, Kononen, M, Lampela, M, Vasander, H, Leblanc, MC, Evers, S, Smith, TEL, Yule, CM, Varkkey, H, Lupascu, M, Parish, F, Singleton, I, Clements, GR, Aziz, SA, Harrison, ME, Cheyne, S, Anshari, GZ, Meijaard, E, Goldstein, JE, Waldron, S, Hergoualc'h, K, Dommain, R, Frolking, S, Evans, CD, Posa, MRC, Glaser, PH, Suryadiputra, N, Lubis, R, Santika, T, Padfield, R, Kurnianto, S, Hadisiswoyo, P, Lim, TW, Page, SE, Gauci, V, Van der Meer, PJ, Buckland, H, Garnier, F, Samuel, MK, Choo, LNLK, O'Reilly, P, Warren, M, Suksuwan, S, Sumarga, E, Jain, A, Laurance, WF, Couwenberg, J, Joosten, H, Vernimmen, R, Hooijer, A, Malins, C, Cochrane, MA, Perumal, B, Siegert, F, Peh, KSH, Corneau, LP, Verchot, L, Harvey, CF, Cobb, A, Jaafar, Z, Wosten, H, Manuri, S, Muller, M, Giesen, W, Phelps, J, Yong, DL, Silvius, M, Wedeux, BMM, Hoyt, A, Osaki, M, Hirano, T, Takahashi, H, Kohyama, TS, Haraguchi, A, Nugroho, NP, Coomes, DA, Quoi, LP, Dohong, A, Gunawan, H, Gaveau, DLA, Langner, A, Lim, FKS, Edwards, DP, Giam, X, Van der Werf, G, Carmenta, R, Verwer, CC, Gibson, L, Grandois, L, Graham, LLB, Regalino, J, Wich, SA, Rieley, J, Kettridge, N, Brown, C, Pirard, R, Moore, S, Capilla, BR, Ballhorn, U, Ho, HC, Hoscilo, A, Lohberger, S, Evans, TA, Yulianti, N, Blackham, G, Onrizal, Husson, S, Murdiyarso, D, Pangala, S, Cole, LES, Tacconi, L, Segah, H, Tonoto, P, Lee, JSH, Schmilewski, G, Wulffraat, S, Putra, EI, Cattau, ME, Clymo, RS, Morrison, R, Mujahid, A, Miettinen, J, Liew, SC, Valpola, S, Wilson, D, D'Arcy, L, Gerding, M, Sundari, S, Thornton, SA, Kalisz, B, Chapman, SJ, Su, ASM, Basuki, I, Itoh, M, Traeholt, C, Sloan, S, Sayok, AK, and Andersen, R
- Abstract
Letter
- Published
- 2017
6. The high costs of conserving Southeast Asia's lowland rainforests
- Author
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Fisher, B, Edwards, D P, Giam, X, Wilcove, D S, University of Zurich, and Fisher, B
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10127 Institute of Evolutionary Biology and Environmental Studies ,1105 Ecology, Evolution, Behavior and Systematics ,Calling Lake ,hierarchical sampling design ,Wog Wog Habitat Fragmentation Experiment ,Fragmentation Experiment ,570 Life sciences ,biology ,590 Animals (Zoology) ,deforestation ,Biological Dynamics of Forest Fragments Project ,2303 Ecology ,Savannah River Site Corridor Experiment - Published
- 2011
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7. Threat or invasive status in legumes is related to opposite extremes of the same ecological and life-history attributes
- Author
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Bradshaw, Corey J. A., Giam, X., Tan, H., Brook, Barry William, Sodhi, N., Bradshaw, Corey J. A., Giam, X., Tan, H., Brook, Barry William, and Sodhi, N.
- Abstract
1. The urgency and scale of the global biodiversity crisis requires the application of generalized predictors of a species’ likelihood of going extinct or becoming invasive in non-native areas. A common approach is to correlate species’ ecological and life-history characteristics (attributes, traits) with the probability of becoming either threatened (responding negatively to human activity), or invasive (responding positively). The limitation of previous studies is that the fates of becoming threatened or invasive have generally been treated in isolation. 2. Here we consider the problem of threat and invasiveness in unison based on analysis of one of the largest-ever species attributes data bases (8906 species) compiled for a single plant family (Fabaceae). We used generalized linear mixed-effects models (using taxonomic grouping to control for within-family phylogenetic relationships) to correlate species’ life-history and ecological traits to three response variables: probability of being (i) threatened or not, (ii) invasive or not, and (iii) threatened or invasive. 3. We found that tall, annual, range-restricted species with tree-like growth forms, inhabiting closed-forest and lowland sites are more likely to be threatened. Conversely, climbing and herbaceous species that naturally span multiple floristic kingdoms and habitat types are more likely to become invasive. 4. Synthesis. These results support the idea that at least for one of the richest plant families, species’ life-history and ecological traits correlate with a fate response to anthropogenic global change. Our results show that species do demonstrate particular susceptibility to either fate based on their evolved traits, and that traits generally correlated with invasiveness are also those that correlate with a reduced probability of becoming threatened.
- Published
- 2008
8. Assessing shorebird mortalities due to razor clam aquaculture at key migratory stopover sites in southeastern China.
- Author
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Liang D, Mu T, Yang Z, Giam X, Wang Y, Li J, Cai S, Zhang X, Wang Y, Liu Y, and Wilcove DS
- Subjects
- Animals, Animal Migration, Birds, China, Aquaculture, Conservation of Natural Resources, Bivalvia
- Abstract
Aquaculture can provide foraging habitat for birds, but it can also result in intentional and accidental mortality. We examined an overlooked conflict between razor clam (Sinonovacula spp.) aquaculture and declining shorebirds in southeastern China's Fujian and Zhejiang provinces. We surveyed 6 out of 11 internationally important stopover sites for these shorebirds and monitored shorebird mortality in 2 sites (Xinghua Bay, Yueqing Bay) with razor clam aquaculture. We visited an additional 32 sites in these 2 provinces to determine if there was netting in other razor clam farms. Approximately 8-9 km
2 of intertidal foraging habitat was covered by horizontal nets to prevent birds from feeding on young razor clams at Xinghua Bay and Yueqing Bay. We conservatively estimated that 13,676 (2.5th-97.5th percentile 8,330-21,285) individual shorebirds were entangled in the nets at the 2 monitored sites in April and May 2021, including 2 endangered and 7 near-threatened species. Mortality of 5 species for which we had sufficient data accounted for 0.76% (black-tailed godwit [Limosa limosa]) to 4.27% (terek sandpiper [Xenus cinereus]) of their total flyway populations. This level of mortality could strongly affect their populations. We found netting at 17 additional razor clam farms, indicating a widespread threat to shorebirds. Although razor clams are typically harvested in late March to early April, nets are left on the mudflats throughout the spring and summer, including when the bulk of shorebird migration takes place. Immediately removing these nets after the clam harvest could prevent most of the spring mortality of shorebirds, although this is unlikely to happen without government regulations or economic incentives. To better assess and mitigate the impacts of this conflict, future research should quantify shorebird mortality at other razor clam farms, including during winter, explore less harmful deterrence methods, and assess the socioeconomic factors driving the conflict., (© 2023 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)- Published
- 2024
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9. Past and recent anthropogenic pressures drive rapid changes in riverine fish communities.
- Author
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Danet A, Giam X, Olden JD, and Comte L
- Subjects
- Animals, Humans, Fresh Water, Fishes, Anthropogenic Effects, Biodiversity
- Abstract
Understanding how and why local communities change is a pressing task for conservation, especially in freshwater systems. It remains challenging because of the complexity of biodiversity changes, driven by the spatio-temporal heterogeneity of human pressures. Using a compilation of riverine fish community time series (93% between 1993 and 2019) across the Palaearctic, Nearctic and Australasia realms, we assessed how past and recent anthropogenic pressures drive community changes across both space and time. We found evidence of rapid changes in community composition of 30% per decade characterized by important changes in the dominant species, together with a 13% increase in total abundance per decade and a 7% increase in species richness per decade. The spatial heterogeneity in these trends could be traced back to the strength and timing of anthropogenic pressures and was mainly mediated by non-native species introductions. Specifically, we demonstrate that the negative effects of anthropogenic pressures on species richness and total abundance were compensated over time by the establishment of non-native species, a pattern consistent with previously reported biotic homogenization at the global scale. Overall, our study suggests that accounting for the complexity of community changes and its drivers is a crucial step to reach global conservation goals., (© 2024. The Author(s).)
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- 2024
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10. Two centuries of biodiversity discovery and loss in Singapore.
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Chisholm RA, Kristensen NP, Rheindt FE, Chong KY, Ascher JS, Lim KKP, Ng PKL, Yeo DCJ, Meier R, Tan HH, Giam X, Yeoh YS, Seah WW, Berman LM, Tan HZ, Sadanandan KR, Theng M, Jusoh WFA, Jain A, Huertas B, Tan DJX, Ng ACR, Teo A, Yiwen Z, Cho TJY, and Sin YCK
- Subjects
- Animals, Singapore, Conservation of Natural Resources, Extinction, Biological, Biodiversity, Mammals, Butterflies
- Abstract
There is an urgent need for reliable data on the impacts of deforestation on tropical biodiversity. The city-state of Singapore has one of the most detailed biodiversity records in the tropics, dating back to the turn of the 19th century. In 1819, Singapore was almost entirely covered in primary forest, but this has since been largely cleared. We compiled more than 200 y of records for 10 major taxonomic groups in Singapore (>50,000 individual records; >3,000 species), and we estimated extinction rates using recently developed and novel statistical models that account for "dark extinctions," i.e., extinctions of undiscovered species. The estimated overall extinction rate was 37% (95% CI [31 to 42%]). Extrapolating our Singapore observations to a future business-as-usual deforestation scenario for Southeast Asia suggests that 18% (95% CI [16 to 22%]) of species will be lost regionally by 2100. Our extinction estimates for Singapore and Southeast Asia are a factor of two lower than previous estimates that also attempted to account for dark extinctions. However, we caution that particular groups such as large mammals, forest-dependent birds, orchids, and butterflies are disproportionately vulnerable., Competing Interests: Competing interests statement:The authors declare no competing interest.
- Published
- 2023
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11. Assessing the illegal hunting of native wildlife in China.
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Liang D, Giam X, Hu S, Ma L, and Wilcove DS
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- Animals, Amphibians, Birds, China, Databases, Factual, Endangered Species economics, Endangered Species legislation & jurisprudence, Endangered Species statistics & numerical data, Mammals, Reptiles, Animals, Wild, Biodiversity, Hunting economics, Hunting legislation & jurisprudence, Hunting statistics & numerical data
- Abstract
Illegal harvesting and trading of wildlife have become major threats to global biodiversity and public health
1-3 . Although China is widely recognized as an important destination for wildlife illegally obtained abroad4 , little attention has been given to illegal hunting within its borders. Here we extracted 9,256 convictions for illegal hunting from a nationwide database of trial verdicts in China spanning January 2014 to March 2020. These convictions involved illegal hunting of 21% (n = 673) of China's amphibian, reptile, bird and mammal species, including 25% of imperilled species in these groups. Sample-based extrapolation indicates that many more species were taken illegally during this period. Larger body mass and range size (for all groups), and proximity to urban markets (for amphibians and birds) increase the probability of a species appearing in the convictions database. Convictions pertained overwhelmingly to illegal hunting for commercial purposes and involved all major habitats across China. A small number of convictions represented most of the animals taken, indicating the existence of large commercial poaching operations. Prefectures closer to urban markets show higher densities of convictions and more individual animals taken. Our results suggest that illegal hunting is a major, overlooked threat to biodiversity throughout China., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2023
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12. Biodiversity conservation adaptation to climate change: Protecting the actors or the stage.
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Zhu G, Giam X, Armsworth PR, Cho SH, and Papeş M
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- Animals, Biodiversity, Ecosystem, Vertebrates, Amphibians, Mammals, Climate Change, Conservation of Natural Resources methods
- Abstract
To be able to protect biodiversity in coming decades, conservation strategies need to consider what sites will be important for species not just today but also in the future. Different methods have been proposed to identify places that will be important for species in the future. Two of the most frequently used methods, ecological niche modeling and climate resilience, have distinct aims. The former focuses on identifying the suitable environmental conditions for species, thus protecting the "actor," namely, the species, whereas the latter seeks to safeguard the "stage," or the landscape in which species occur. We used the two methods to identify climate refugia for 258 forest vertebrates under short- and long-term climatic changes in a biodiversity hotspot, the Appalachian ecoregion of the United States. We also evaluated the spatial congruence of the two approaches for a possible conservation application, that of protecting 30% of the Appalachian region, in line with recent national and international policy recommendations. We detected weak positive correlations between resilience scores and baseline vertebrate richness, estimated with ecological niche models for historical (baseline) climatic conditions. The correlations were stronger for amphibians and mammals than for birds and reptiles. Under climate change scenarios, the correlations between estimated vertebrate richness and resilience were also weakly positive; a positive correlation was detected only for amphibians. Locations with estimated future gain of suitable climatic conditions for vertebrates showed low correlation with resilience. Overall, our results indicate that climate resilience and ecological niche modeling approaches capture different characteristics of projected distributional changes of Appalachian vertebrates. A climate resilience (the stage) approach could be more effective in safeguarding species with low dispersal abilities, whereas an ecological niche modeling (the actor) approach could be more suitable for species with long-distance dispersal capacity because they may be more broadly impacted by climate and less sensitive to geophysical features captured by a climate resilience approach., (© 2022 The Authors. Ecological Applications published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)
- Published
- 2023
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13. Scale of population synchrony confirms macroecological estimates of minimum viable range size.
- Author
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Carvajal-Quintero J, Comte L, Giam X, Olden JD, Brose U, Erős T, Filipe AF, Fortin MJ, Irving K, Jacquet C, Larsen S, Ruhi A, Sharma S, Villalobos F, and Tedesco PA
- Subjects
- Animals, Biodiversity, Extinction, Biological, Fishes, Endangered Species, Ecosystem, Conservation of Natural Resources
- Abstract
Global ecosystems are facing a deepening biodiversity crisis, necessitating robust approaches to quantifying species extinction risk. The lower limit of the macroecological relationship between species range and body size has long been hypothesized as an estimate of the relationship between the minimum viable range size (MVRS) needed for species persistence and the organismal traits that affect space and resource requirements. Here, we perform the first explicit test of this assumption by confronting the MVRS predicted by the range-body size relationship with an independent estimate based on the scale of synchrony in abundance among spatially separated populations of riverine fish. We provide clear evidence of a positive relationship between the scale of synchrony and species body size, and strong support for the MVRS set by the lower limit of the range-body size macroecological relationship. This MVRS may help prioritize first evaluations for unassessed or data-deficient taxa in global conservation assessments., (© 2022 The Authors. Ecology Letters published by John Wiley & Sons Ltd.)
- Published
- 2023
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14. Author Correction: Species traits and reduced habitat suitability limit efficacy of climate change refugia in streams.
- Author
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Troia MJ, Kaz AL, Niemeyer JC, and Giam X
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- 2022
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15. The relative influence of history, climate, topography and vegetation structure on local animal richness varies among taxa and spatial grains.
- Author
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Carrasco L, Giam X, Sheldon KS, and Papeş M
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- Animals, Bayes Theorem, Climate, Ecosystem, Mammals, Biodiversity, Coleoptera
- Abstract
Understanding the spatial scales at which environmental factors drive species richness patterns is a major challenge in ecology. Due to the trade-off between spatial grain and extent, studies tend to focus on a single spatial scale, and the effects of multiple environmental variables operating across spatial scales on the pattern of local species richness have rarely been investigated. Here, we related variation in local species richness of ground beetles, landbirds and small mammals to variation in vegetation structure and topography, regional climate, biome diversity and glaciation history for 27 sites across the USA at two different spatial grains. We studied the relative influence of broad-scale (landscape) environmental conditions using variables estimated at the site level (climate, productivity, biome diversity and glacial era ice cover) and fine-scale (local) environmental conditions using variables estimated at the plot level (topography and vegetation structure) to explain local species richness. We also examined whether plot-level factors scale up to drive continental scale richness patterns. We used Bayesian hierarchical models and quantified the amount of variance in observed richness that was explained by environmental factors at different spatial scales. For all three animal groups, our models explained much of the variation in local species richness (85%-89%), but site-level variables explained a greater proportion of richness variance than plot-level variables. Temperature was the most important site-level predictor for explaining variance in landbirds and ground beetles richness. Some aspects of vegetation structure were the main plot-level predictors of landbird richness. Environmental predictors generally had poor explanatory power for small mammal richness, while glacial era ice cover was the most important site-level predictor. Relationships between plot-level factors and richness varied greatly among geographical regions and spatial grains, and most relationships did not hold when predictors were scaled up to the continental scale. Our results suggest that the factors that determine richness may be highly dependent on spatial grain, geography, and animal group. We demonstrate that instead of artificially manipulating the resolution to study multiscale effects, a hierarchical approach that uses fine grain data at broad extents could help solve the issue of scale selection in environment-richness studies., (© 2022 The Authors. Journal of Animal Ecology © 2022 British Ecological Society.)
- Published
- 2022
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16. Climate and land-use changes interact to drive long-term reorganization of riverine fish communities globally.
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Comte L, Olden JD, Tedesco PA, Ruhi A, and Giam X
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- Animals, Geography, Models, Theoretical, Temperature, Time Factors, Water Movements, Climate Change, Fishes physiology, Internationality, Rivers
- Abstract
As climate change unfolds, changes in population dynamics and species distribution ranges are expected to fundamentally reshuffle communities worldwide. Yet, a comprehensive understanding of the mechanisms and extent of community reorganization remains elusive. This is particularly true in riverine systems, which are simultaneously exposed to changing temperature and streamflow, and where land-use change continues to be a major driver of biodiversity loss. Here, we use the most comprehensive compilation of fish abundance time series to date to provide a global synthesis of climate- and LU-induced effects on riverine biota with respect to changes in species thermal and streamflow affinities. We demonstrate that fish communities are increasingly dominated by thermophilic (warm-water) and limnophilic (slow-water) species. Despite being consistent with trends in water temperature and streamflow observed over recent decades, these community changes appear largely decoupled from each other and show wide spatial variation. We further reveal a synergy among climate- and land use-related drivers, such that community thermophilization is heightened in more human-modified systems. Importantly, communities in which species experience thermal and flow regimes that approach or exceed their tolerance thresholds (high community sensitivity), as well as species-poor communities (low community resilience), also display faster rates of compositional change. This research illustrates that quantifying vulnerability of riverine systems to climate change requires a broadening from a narrower thermal focus to more integrative approaches that account for the spatially varying and multifaceted sensitivity of riverine organisms to the interactive effects of water temperature, hydrology, and other anthropogenic changes., Competing Interests: The authors declare no competing interest.
- Published
- 2021
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17. Global progress in incorporating climate adaptation into land protection for biodiversity since Aichi targets.
- Author
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Carrasco L, Papeş M, Sheldon KS, and Giam X
- Subjects
- Acclimatization, Climate Change, Ecosystem, Refugium, Biodiversity, Conservation of Natural Resources
- Abstract
Climate adaptation strategies are being developed and implemented to protect biodiversity from the impacts of climate change. A well-established strategy involves the identification and addition of new areas for conservation, and most countries agreed in 2010 to expand the global protected area (PA) network to 17% by 2020 (Aichi Biodiversity Target 11). Although great efforts to expand the global PA network have been made, the potential of newly established PAs to conserve biodiversity under future climate change remains unclear at the global scale. Here, we conducted the first global-extent, country-level assessment of the contribution of PA network expansion toward three key land prioritization approaches for biodiversity persistence under climate change: protecting climate refugia, protecting abiotic diversity, and increasing connectivity. These approaches avoid uncertainties of biodiversity predictions under climate change as well as the issue of undescribed species. We found that 51% of the countries created new PAs in locations with lower mean climate velocity (representing better climate refugia) and 58% added PAs in areas with higher mean abiotic diversity compared to the available, non-human-dominated lands not chosen for protection. However, connectivity among PAs declined in 53% of the countries, indicating that many new PAs were located far from existing PAs. Lastly, we identified potential improvements for climate adaptation, showing that 94% of the countries have the opportunity to improve in executing one or more approaches to conserve biodiversity. Most countries (60%) were associated with multiple opportunities, highlighting the need for integrative strategies that target multiple land protection approaches. Our results demonstrate that a global improvement in the protection of climate refugia, abiotic diversity, and connectivity of reserves is needed to complement land protection informed by existing and projected species distributions. Our study also provides a framework for countries to prioritize land protection for climate adaptation using publicly available data., (© 2021 John Wiley & Sons Ltd.)
- Published
- 2021
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18. The geography of metapopulation synchrony in dendritic river networks.
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Larsen S, Comte L, Filipa Filipe A, Fortin MJ, Jacquet C, Ryser R, Tedesco PA, Brose U, Erős T, Giam X, Irving K, Ruhi A, Sharma S, and Olden JD
- Subjects
- Animals, Europe, Geography, Population Dynamics, Ecosystem, Rivers
- Abstract
Dendritic habitats, such as river ecosystems, promote the persistence of species by favouring spatial asynchronous dynamics among branches. Yet, our understanding of how network topology influences metapopulation synchrony in these ecosystems remains limited. Here, we introduce the concept of fluvial synchrogram to formulate and test expectations regarding the geography of metapopulation synchrony across watersheds. By combining theoretical simulations and an extensive fish population time-series dataset across Europe, we provide evidence that fish metapopulations can be buffered against synchronous dynamics as a direct consequence of network connectivity and branching complexity. Synchrony was higher between populations connected by direct water flow and decayed faster with distance over the Euclidean than the watercourse dimension. Likewise, synchrony decayed faster with distance in headwater than mainstem populations of the same basin. As network topology and flow directionality generate fundamental spatial patterns of synchrony in fish metapopulations, empirical synchrograms can aid knowledge advancement and inform conservation strategies in complex habitats., (© 2021 The Authors. Ecology Letters published by John Wiley & Sons Ltd.)
- Published
- 2021
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19. Quantifying the relative performance of two undetected-extinction models.
- Author
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Lum D, Tedesco PA, Hugueny B, Giam X, and Chisholm RA
- Subjects
- Animals, Australia, Biodiversity, Birds, Conservation of Natural Resources, Extinction, Biological
- Abstract
Extinctions of undiscovered species (undetected extinctions) constitute a portion of biodiversity loss that is often ignored. We compared the performance of 2 models of undetected extinctions - Tedesco and SEUX - when estimating undetected extinctions with both simulated and real-world data. We generated simulated data by considering a birth-death process in which less abundant species were more likely to go extinct. When detection rates were higher for common species, the 2 models underestimated the true number of undetected extinctions by up to 88.7%, and when detection rates were independent of abundance, the 2 models performed better; the SEUX model had an average bias of +3.1% and the Tedesco model had an average bias of -62.3%. We applied the models to 8 real-world data sets (e.g., Australian amphibians, Australian birds, North American bivalves) and found that true extinctions may be from 15% to 180% higher than observed values. For 6 of the 8 data sets, the SEUX model yielded absolute estimates that were 5.7-66.8% lower than those of the Tedesco model. We mainly attributed this difference to the SEUX model's assumption that there are no undetected extant species currently. We assessed the accuracy of the models' estimates with a logistic regression to test whether detection and extinction rates were uncorrelated across species. Rates were correlated for 3 of the 8 data sets; species discovered later had a higher probability of being extinct, suggesting that extinction numbers could be even higher for these groups. Despite caveats associated with the models, the evidence from both show biodiversity loss in these groups may be more severe than what has been documented., (© 2020 Society for Conservation Biology.)
- Published
- 2021
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20. Species traits and reduced habitat suitability limit efficacy of climate change refugia in streams.
- Author
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Troia MJ, Kaz AL, Niemeyer JC, and Giam X
- Subjects
- Animals, Ecosystem, Fishes, Refugium, Climate Change, Rivers
- Abstract
Climate change vulnerability depends on whether organisms can disperse rapidly enough to keep pace with shifting temperatures and find suitable habitat along the way. Here, we develop a method to examine where and for which species shifting isotherms will outpace species dispersal using stream networks of the southern Appalachian Mountains (United States) and their highly speciose and endemic fish fauna as a model system. By exploring alternative tributary and mainstem dispersal pathways, we identify tributaries as slow-climate-velocity pathways along which some fish can successfully disperse and thus keep pace with climate change. Despite accessibility and thermal suitability, non-temperature habitat conditions in tributaries are unsuitable for some dispersing species, thus probably precluding establishment of persistent populations. Our findings demonstrate a trade-off shaping the efficacy of thermal refugia that depends on species-specific habitat associations and reveal individual-level dispersal behaviour, body size and stream network geometry as general correlates of climate change vulnerability.
- Published
- 2019
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21. Examining conservation compliance with randomized response technique analyses.
- Author
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Chang CH, Cruyff MJLF, and Giam X
- Subjects
- Humans, Natural Resources, Prevalence, Surveys and Questionnaires, Conservation of Natural Resources, Models, Statistical
- Abstract
Understanding violations of laws or social norms designed to protect natural resources from overexploitation is a priority for conservation research and management. Because direct questioning about stigmatized behaviors can produce biased responses, researchers have adopted more complex, indirect questioning techniques. The randomized response technique (RRT) is one of the most powerful indirect survey methods, yet analyses of these data require sophisticated statistical models. To date, there has been limited user-friendly software to analyze RRT data, particularly for models that combine information from multiple RRT questions. We developed an R package, zapstRR (ZoologicAl Package for RRT) that provides functions for 3 RRT models that can be applied to single or multiple RRT questions. With these functions, researchers can estimate the prevalence of conservation noncompliance, determine the number of violations by individuals, perform regressions for univariate and multivariate RRT data, and correct prevalence estimates for evasive-response bias. We illustrate the use of these estimators for RRT data through an examination of 2 case studies: illegal bird hunting where the interview consisted of a standard RRT question design and a novel implementation designed to offer further anonymity to respondents and reveal the impact of educational interventions on illegal bushmeat consumption. The case studies demonstrate how the models can work in tandem to uncover distinct patterns within RRT data sets. The case studies also show how several assumptions are central to the application of the multivariate models., (© 2018 Society for Conservation Biology.)
- Published
- 2018
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22. Counteracting estimation bias and social influence to improve the wisdom of crowds.
- Author
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Kao AB, Berdahl AM, Hartnett AT, Lutz MJ, Bak-Coleman JB, Ioannou CC, Giam X, and Couzin ID
- Subjects
- Humans, Likelihood Functions, Social Behavior, Statistics as Topic, Knowledge, Social Networking
- Abstract
Aggregating multiple non-expert opinions into a collective estimate can improve accuracy across many contexts. However, two sources of error can diminish collective wisdom: individual estimation biases and information sharing between individuals. Here, we measure individual biases and social influence rules in multiple experiments involving hundreds of individuals performing a classic numerosity estimation task. We first investigate how existing aggregation methods, such as calculating the arithmetic mean or the median, are influenced by these sources of error. We show that the mean tends to overestimate, and the median underestimate, the true value for a wide range of numerosities. Quantifying estimation bias, and mapping individual bias to collective bias, allows us to develop and validate three new aggregation measures that effectively counter sources of collective estimation error. In addition, we present results from a further experiment that quantifies the social influence rules that individuals employ when incorporating personal estimates with social information. We show that the corrected mean is remarkably robust to social influence, retaining high accuracy in the presence or absence of social influence, across numerosities and across different methods for averaging social information. Using knowledge of estimation biases and social influence rules may therefore be an inexpensive and general strategy to improve the wisdom of crowds., (© 2018 The Author(s).)
- Published
- 2018
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23. Global biodiversity loss from tropical deforestation.
- Author
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Giam X
- Subjects
- Trees, Tropical Climate, Biodiversity, Conservation of Natural Resources
- Abstract
Competing Interests: The author declares no conflict of interest.
- Published
- 2017
- Full Text
- View/download PDF
24. Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences.
- Author
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Wijedasa LS, Jauhiainen J, Könönen M, Lampela M, Vasander H, Leblanc MC, Evers S, Smith TE, Yule CM, Varkkey H, Lupascu M, Parish F, Singleton I, Clements GR, Aziz SA, Harrison ME, Cheyne S, Anshari GZ, Meijaard E, Goldstein JE, Waldron S, Hergoualc'h K, Dommain R, Frolking S, Evans CD, Posa MR, Glaser PH, Suryadiputra N, Lubis R, Santika T, Padfield R, Kurnianto S, Hadisiswoyo P, Lim TW, Page SE, Gauci V, Van Der Meer PJ, Buckland H, Garnier F, Samuel MK, Choo LN, O'Reilly P, Warren M, Suksuwan S, Sumarga E, Jain A, Laurance WF, Couwenberg J, Joosten H, Vernimmen R, Hooijer A, Malins C, Cochrane MA, Perumal B, Siegert F, Peh KS, Comeau LP, Verchot L, Harvey CF, Cobb A, Jaafar Z, Wösten H, Manuri S, Müller M, Giesen W, Phelps J, Yong DL, Silvius M, Wedeux BM, Hoyt A, Osaki M, Hirano T, Takahashi H, Kohyama TS, Haraguchi A, Nugroho NP, Coomes DA, Quoi LP, Dohong A, Gunawan H, Gaveau DL, Langner A, Lim FK, Edwards DP, Giam X, Van Der Werf G, Carmenta R, Verwer CC, Gibson L, Gandois L, Graham LL, Regalino J, Wich SA, Rieley J, Kettridge N, Brown C, Pirard R, Moore S, Capilla BR, Ballhorn U, Ho HC, Hoscilo A, Lohberger S, Evans TA, Yulianti N, Blackham G, Onrizal, Husson S, Murdiyarso D, Pangala S, Cole LE, Tacconi L, Segah H, Tonoto P, Lee JS, Schmilewski G, Wulffraat S, Putra EI, Cattau ME, Clymo RS, Morrison R, Mujahid A, Miettinen J, Liew SC, Valpola S, Wilson D, D'Arcy L, Gerding M, Sundari S, Thornton SA, Kalisz B, Chapman SJ, Su AS, Basuki I, Itoh M, Traeholt C, Sloan S, Sayok AK, and Andersen R
- Published
- 2017
- Full Text
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25. Coexistence and Conflict between the Island Flying fox ( Pteropus hypomelanus ) and Humans on Tioman Island, Peninsular Malaysia.
- Author
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Aziz SA, Clements GR, Giam X, Forget PM, and Campos-Arceiz A
- Abstract
As tropical landscapes become increasingly human-dominated, conflicts between people and wildlife threaten ecological processes. Old World fruit bats such as flying foxes are especially susceptible to extinction risk because there is low interest in their conservation, particularly when they are considered pests. In order to arrest fruit bat declines, there is an urgent need to understand human-bat conflict and its implications. On a tropical island in Peninsular Malaysia, we conducted a questionnaire survey to investigate coexistence between people and the island flying fox ( Pteropus hypomelanus ). Among 119 respondents, knowledge of ecosystem services provided by flying foxes was extremely low. Most respondents held negative attitudes towards the bats, and older male locals were more likely to support killing them. This was also true for older owners of fruit trees who derived income from selling fruit, and experienced flying fox raids. Our results can be used to design appropriate interventions to support conservation efforts, and has important implications for managing conflicts between humans and synanthropic wildlife.
- Published
- 2017
- Full Text
- View/download PDF
26. Trade-offs between savanna woody plant diversity and carbon storage in the Brazilian Cerrado.
- Author
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Pellegrini AF, Socolar JB, Elsen PR, and Giam X
- Subjects
- Australia, Biodiversity, Brazil, Carbon, Ecosystem, Grassland, Trees, Climate Change
- Abstract
Incentivizing carbon storage can be a win-win pathway to conserving biodiversity and mitigating climate change. In savannas, however, the situation is more complex. Promoting carbon storage through woody encroachment may reduce plant diversity of savanna endemics, even as the diversity of encroaching forest species increases. This trade-off has important implications for the management of biodiversity and carbon in savanna habitats, but has rarely been evaluated empirically. We quantified the nature of carbon-diversity relationships in the Brazilian Cerrado by analyzing how woody plant species richness changed with carbon storage in 206 sites across the 2.2 million km(2) region at two spatial scales. We show that total woody plant species diversity increases with carbon storage, as expected, but that the richness of endemic savanna woody plant species declines with carbon storage both at the local scale, as woody biomass accumulates within plots, and at the landscape scale, as forest replaces savanna. The sharpest trade-offs between carbon storage and savanna diversity occurred at the early stages of carbon accumulation at the local scale but the final stages of forest encroachment at the landscape scale. Furthermore, the loss of savanna species quickens in the final stages of forest encroachment, and beyond a point, savanna species losses outpace forest species gains with increasing carbon accumulation. Our results suggest that although woody encroachment in savanna ecosystems may provide substantial carbon benefits, it comes at the rapidly accruing cost of woody plant species adapted to the open savanna environment. Moreover, the dependence of carbon-diversity trade-offs on the amount of savanna area remaining requires land managers to carefully consider local conditions. Widespread woody encroachment in both Australian and African savannas and grasslands may present similar threats to biodiversity., (© 2016 John Wiley & Sons Ltd.)
- Published
- 2016
- Full Text
- View/download PDF
27. A robust nonparametric method for quantifying undetected extinctions.
- Author
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Chisholm RA, Giam X, Sadanandan KR, Fung T, and Rheindt FE
- Subjects
- Animals, Birds, Singapore, Biodiversity, Conservation of Natural Resources, Extinction, Biological
- Abstract
How many species have gone extinct in modern times before being described by science? To answer this question, and thereby get a full assessment of humanity's impact on biodiversity, statistical methods that quantify undetected extinctions are required. Such methods have been developed recently, but they are limited by their reliance on parametric assumptions; specifically, they assume the pools of extant and undetected species decay exponentially, whereas real detection rates vary temporally with survey effort and real extinction rates vary with the waxing and waning of threatening processes. We devised a new, nonparametric method for estimating undetected extinctions. As inputs, the method requires only the first and last date at which each species in an ensemble was recorded. As outputs, the method provides estimates of the proportion of species that have gone extinct, detected, or undetected and, in the special case where the number of undetected extant species in the present day is assumed close to zero, of the absolute number of undetected extinct species. The main assumption of the method is that the per-species extinction rate is independent of whether a species has been detected or not. We applied the method to the resident native bird fauna of Singapore. Of 195 recorded species, 58 (29.7%) have gone extinct in the last 200 years. Our method projected that an additional 9.6 species (95% CI 3.4, 19.8) have gone extinct without first being recorded, implying a true extinction rate of 33.0% (95% CI 31.0%, 36.2%). We provide R code for implementing our method. Because our method does not depend on strong assumptions, we expect it to be broadly useful for quantifying undetected extinctions., (© 2016 Society for Conservation Biology.)
- Published
- 2016
- Full Text
- View/download PDF
28. Community-wide changes in intertaxonomic temporal co-occurrence resulting from phenological shifts.
- Author
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Hua F, Hu J, Liu Y, Giam X, Lee TM, Luo H, Wu J, Liang Q, Zhao J, Long X, Pang H, Wang B, Liang W, Zhang Z, Gao X, and Zhu J
- Subjects
- Animals, Biota, China, Seasons, Species Specificity, Weather, Animal Distribution, Climate Change, Insecta physiology, Vertebrates physiology
- Abstract
Global climate change is known to affect the assembly of ecological communities by altering species' spatial distribution patterns, but little is known about how climate change may affect community assembly by changing species' temporal co-occurrence patterns, which is highly likely given the widely observed phenological shifts associated with climate change. Here, we analyzed a 29-year phenological data set comprising community-level information on the timing and span of temporal occurrence in 11 seasonally occurring animal taxon groups from 329 local meteorological observatories across China. We show that widespread shifts in phenology have resulted in community-wide changes in the temporal overlap between taxa that are dominated by extensions, and that these changes are largely due to taxa's altered span of temporal occurrence rather than the degree of synchrony in phenological shifts. Importantly, our findings also suggest that climate change may have led to less phenological mismatch than generally presumed, and that the context under which to discuss the ecological consequences of phenological shifts should be expanded beyond asynchronous shifts., (© 2015 John Wiley & Sons Ltd.)
- Published
- 2016
- Full Text
- View/download PDF
29. Mitigating the impact of oil-palm monoculture on freshwater fishes in Southeast Asia.
- Author
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Giam X, Hadiaty RK, Tan HH, Parenti LR, Wowor D, Sauri S, Chong KY, Yeo DC, and Wilcove DS
- Subjects
- Animals, Borneo, Fresh Water, Indonesia, Agriculture, Arecaceae, Biodiversity, Conservation of Natural Resources, Fishes physiology
- Abstract
Anthropogenic land-cover change is driving biodiversity loss worldwide. At the epicenter of this crisis lies Southeast Asia, where biodiversity-rich forests are being converted to oil-palm monocultures. As demand for palm oil increases, there is an urgent need to find strategies that maintain biodiversity in plantations. Previous studies found that retaining forest patches within plantations benefited some terrestrial taxa but not others. However, no study has focused on aquatic taxa such as fishes, despite their importance to human well-being. We assessed the efficacy of forested riparian reserves in conserving freshwater fish biodiversity in oil-palm monoculture by sampling stream fish communities in an oil-palm plantation in Central Kalimantan, Indonesia. Forested riparian reserves maintained preconversion local fish species richness and functional diversity. In contrast, local and total species richness, biomass, and functional diversity declined markedly in streams without riparian reserves. Mechanistically, riparian reserves appeared to increase local species richness by increasing leaf litter cover and maintaining coarse substrate. The loss of fishes specializing in leaf litter and coarse substrate decreased functional diversity and altered community composition in oil-palm plantation streams that lacked riparian reserves. Thus, a land-sharing strategy that incorporates the retention of forested riparian reserves may maintain the ecological integrity of fish communities in oil-palm plantations. We urge policy makers and growers to make retention of riparian reserves in oil-palm plantations standard practice, and we encourage palm-oil purchasers to source only palm oil from plantations that employ this practice., (© 2015 Society for Conservation Biology.)
- Published
- 2015
- Full Text
- View/download PDF
30. Avian responses to selective logging shaped by species traits and logging practices.
- Author
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Burivalova Z, Lee TM, Giam X, Şekercioğlu ÇH, Wilcove DS, and Koh LP
- Subjects
- Animals, Biodiversity, Food Chain, Forests, Models, Theoretical, Tropical Climate, Birds physiology, Conservation of Natural Resources, Forestry methods
- Abstract
Selective logging is one of the most common forms of forest use in the tropics. Although the effects of selective logging on biodiversity have been widely studied, there is little agreement on the relationship between life-history traits and tolerance to logging. In this study, we assessed how species traits and logging practices combine to determine species responses to selective logging, based on over 4000 observations of the responses of nearly 1000 bird species to selective logging across the tropics. Our analysis shows that species traits, such as feeding group and body mass, and logging practices, such as time since logging and logging intensity, interact to influence a species' response to logging. Frugivores and insectivores were most adversely affected by logging and declined further with increasing logging intensity. Nectarivores and granivores responded positively to selective logging for the first two decades, after which their abundances decrease below pre-logging levels. Larger species of omnivores and granivores responded more positively to selective logging than smaller species from either feeding group, whereas this effect of body size was reversed for carnivores, herbivores, frugivores and insectivores. Most importantly, species most negatively impacted by selective logging had not recovered approximately 40 years after logging cessation. We conclude that selective timber harvest has the potential to cause large and long-lasting changes in avian biodiversity. However, our results suggest that the impacts can be mitigated to a certain extent through specific forest management strategies such as lengthening the rotation cycle and implementing reduced impact logging., (© 2015 The Author(s) Published by the Royal Society. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
31. Tropical crops: cautious optimism.
- Author
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Giam X, Koh LP, and Wilcove DS
- Subjects
- Conservation of Natural Resources, Crops, Agricultural, Plant Oils, Trees
- Published
- 2014
- Full Text
- View/download PDF
32. Navjot's nightmare revisited: logging, agriculture, and biodiversity in Southeast Asia.
- Author
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Wilcove DS, Giam X, Edwards DP, Fisher B, and Koh LP
- Subjects
- Asia, Southeastern, Ecosystem, Agriculture, Biodiversity, Conservation of Natural Resources, Forestry
- Abstract
In 2004, Navjot Sodhi and colleagues warned that logging and agricultural conversion of Southeast Asia's forests were leading to a biodiversity disaster. We evaluate this prediction against subsequent research and conclude that most of the fauna of the region can persist in logged forests. Conversely, conversion of primary or logged forests to plantation crops, such as oil palm, causes tremendous biodiversity loss. This loss is exacerbated by increased fire frequency. Therefore, we conclude that preventing agricultural conversion of logged forests is essential to conserving the biodiversity of this region. Our analysis also suggests that, because Southeast Asian forests are tightly tied to global commodity markets, conservation payments commensurate with combined returns from logging and subsequent agricultural production may be required to secure long-term forest protection., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
33. Reservoirs of richness: least disturbed tropical forests are centres of undescribed species diversity.
- Author
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Giam X, Scheffers BR, Sodhi NS, Wilcove DS, Ceballos G, and Ehrlich PR
- Subjects
- Animals, Ecosystem, Endangered Species, Geography, Models, Biological, Tropical Climate, Amphibians classification, Biodiversity, Conservation of Natural Resources, Mammals classification
- Abstract
In the last few decades, there has been a remarkable discovery of new species of plants, invertebrates and vertebrates, in what have been called the new age of discovery. However, owing to anthropogenic impacts such as habitat conversion, many of the still unknown species may go extinct before being scientifically documented (i.e. 'crypto-extinctions'). Here, by applying a mathematical model of species descriptions which accounts for taxonomic effort, we show that even after 250 years of taxonomic classification, about 3050 amphibians and at least 160 land mammal species remain to be discovered and described. These values represent, respectively, 33 and 3 per cent of the current species total for amphibians and land mammals. We found that tropical moist forests of the Neotropics, Afrotropics and Indomalaya probably harbour the greatest numbers of undescribed species. Tropical forests with minimal anthropogenic disturbance are predicted to have larger proportions of undescribed species. However, the protected area coverage is low in many of these key biomes. Moreover, undescribed species are likely to be at a greater risk of extinction compared with known species because of small geographical ranges among other factors. By highlighting the key areas of undescribed species diversity, our study provides a starting template to rapidly document these species and protect them through better habitat management.
- Published
- 2012
- Full Text
- View/download PDF
34. The world's rediscovered species: back from the brink?
- Author
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Scheffers BR, Yong DL, Harris JB, Giam X, and Sodhi NS
- Subjects
- Amphibians, Animals, Birds, Endangered Species, Mammals, Species Specificity, Conservation of Natural Resources, Extinction, Biological
- Abstract
Each year, numerous species thought to have disappeared are rediscovered. Yet, do these rediscoveries represent the return of viable populations or the delayed extinction of doomed species? We document the number, distribution and conservation status of rediscovered amphibian, bird, and mammal species globally. Over the past 122 years, at least 351 species have been rediscovered, most occurring in the tropics. These species, on average, were missing for 61 years before being rediscovered (range of 3-331 years). The number of rediscoveries per year increased over time and the majority of these rediscoveries represent first documentations since their original description. Most rediscovered species have restricted ranges and small populations, and 92% of amphibians, 86% of birds, and 86% of mammals are highly threatened, independent of how long they were missing or when they were rediscovered. Under the current trends of widespread habitat loss, particularly in the tropics, most rediscovered species remain on the brink of extinction.
- Published
- 2011
- Full Text
- View/download PDF
35. Evaluating the relative environmental impact of countries.
- Author
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Bradshaw CJ, Giam X, and Sodhi NS
- Subjects
- Ecosystem, Geography, Socioeconomic Factors, Environment, Internationality
- Abstract
Environmental protection is critical to maintain ecosystem services essential for human well-being. It is important to be able to rank countries by their environmental impact so that poor performers as well as policy 'models' can be identified. We provide novel metrics of country-specific environmental impact ranks - one proportional to total resource availability per country and an absolute (total) measure of impact - that explicitly avoid incorporating confounding human health or economic indicators. Our rankings are based on natural forest loss, habitat conversion, marine captures, fertilizer use, water pollution, carbon emissions and species threat, although many other variables were excluded due to a lack of country-specific data. Of 228 countries considered, 179 (proportional) and 171 (absolute) had sufficient data for correlations. The proportional index ranked Singapore, Korea, Qatar, Kuwait, Japan, Thailand, Bahrain, Malaysia, Philippines and Netherlands as having the highest proportional environmental impact, whereas Brazil, USA, China, Indonesia, Japan, Mexico, India, Russia, Australia and Peru had the highest absolute impact (i.e., total resource use, emissions and species threatened). Proportional and absolute environmental impact ranks were correlated, with mainly Asian countries having both high proportional and absolute impact. Despite weak concordance among the drivers of environmental impact, countries often perform poorly for different reasons. We found no evidence to support the environmental Kuznets curve hypothesis of a non-linear relationship between impact and per capita wealth, although there was a weak reduction in environmental impact as per capita wealth increases. Using structural equation models to account for cross-correlation, we found that increasing wealth was the most important driver of environmental impact. Our results show that the global community not only has to encourage better environmental performance in less-developed countries, especially those in Asia, there is also a requirement to focus on the development of environmentally friendly practices in wealthier countries.
- Published
- 2010
- Full Text
- View/download PDF
36. Preface.
- Author
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Kjøller A
- Published
- 1996
- Full Text
- View/download PDF
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