Journal articles: 'Biotic refuge'

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Murphy, Karen A., Joel H. Reynolds, and John M. Koltun. "Evaluating the ability of the differenced Normalized Burn Ratio (dNBR) to predict ecologically significant burn severity in Alaskan boreal forests." International Journal of Wildland Fire 17, no. 4 (2008): 490. http://dx.doi.org/10.1071/wf08050.

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During the 2004 fire season ~6.6 million acres (~2.7 million ha) burned across Alaska. Nearly 2 million of these were on National Wildlife Refuge System lands inaccessible from the state’s limited road system. Many fires burned through September, driven by unusually warm and dry temperatures throughout the summer. Using several fires from this season, we assessed the national burn severity methodology’s performance on refuge lands. Six fires, spanning 814 489 acres (329 613 ha), were sampled on five boreal forest refuges. In total, 347 sites were sampled for vegetation composition and ground-based burn severity estimates following the national protocols. The relationship between the differenced Normalized Burn Ratio (dNBR) and composite burn index (CBI) was unexpectedly weak (R2adjusted, 0.11–0.64). The weak relationship was not a result of data or image processing errors, nor of any biotic or abiotic confounding variable. The inconsistent results, and dNBR’s limited ability to discern the ecologically significant differences within moderate and high severity burn sites, indicate that the current methodology does not satisfy key Alaskan boreal forest management objectives.

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McDonald, Peter J., Alistair Stewart, Melissa A. Jensen, and Hugh W. McGregor. "Topographic complexity potentially mediates cat predation risk for a critically endangered rodent." Wildlife Research 47, no. 8 (2020): 643. http://dx.doi.org/10.1071/wr19172.

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ContextThe niche reduction hypothesis (NRH) predicts that the realised niche of declining species is reduced by threats that are mediated by environmental, biotic and evolutionary processes, explaining why species decline in some locations but not others. The critically endangered central rock-rat (CRR) survives only in rugged mountain range habitat in central Australia and is highly vulnerable to cat predation. We predicted that cat density and ranging behaviour, and, hence, predation risk, is mediated by habitat complexity, thus explaining the mechanism maintaining the CRR refuge. AimsWe sought to determine whether cat densities were lower in the rugged CRR refuge than in an adjacent valley dominated by less complex rocky habitats and no longer occupied by CRRs. MethodsWe installed arrays of camera traps along two parallel mountain ranges in the refuge and in the intervening valley habitats. We identified uniquely patterned individual cats and compared spatially explicit capture–recapture (SECR) models to evaluate our hypothesis that cat density varies with topographic complexity. Key resultsThe dominant effect in all models was the significant negative relationship between cat detection probability and fine-scale topographic ruggedness. Two of the best three SECR models indicated lower cat densities and relative home-range sizes in the refuge than in the valley. In total, 17% of cats were detected in both habitat types. ConclusionsWe found some evidence that cat density and home-range size were mediated by habitat complexity. Further, the negative relationship between cat detection probability and topographic complexity suggests that cats spend less time foraging in CRR refuge habitat. ImplicationsCat management programs, aimed at reducing predation pressure on the CRR, must include the refuge and surrounding habitats to control cats that pose a threat to CRR subpopulations.

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Tallowin, Oliver J. S., Shai Meiri, Stephen C. Donnellan, Stephen J. Richards, Christopher C. Austin, and Paul M. Oliver. "The other side of the Sahulian coin: biogeography and evolution of Melanesian forest dragons (Agamidae)." Biological Journal of the Linnean Society 129, no. 1 (November 12, 2019): 99–113. http://dx.doi.org/10.1093/biolinnean/blz125.

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Abstract New Guinea has been considered both as a refuge for mesic rainforest-associated lineages that contracted in response to the late Cenozoic aridification of Australia and as a centre of biotic diversification and radiation since the mid-Miocene or earlier. Here, we estimate the diversity and a phylogeny for the Australo-Papuan forest dragons (Sauria: Agamidae; ~20 species) in order to examine the following: (1) whether New Guinea and/or proto-Papuan Islands may have been a biogeographical refuge or a source for diversity in Australia; (2) whether mesic rainforest environments are ancestral to the entire radiation, as may be predicted by the New Guinea refuge hypothesis; and (3) more broadly, how agamid ecological diversity varies across the contrasting environments of Australia and New Guinea. Patterns of lineage distribution and diversity suggest that extinction in Australia, and colonization and radiation on proto-Papuan islands, have both shaped the extant diversity and distribution of forest dragons since the mid-Miocene. The ancestral biome for all Australo-Papuan agamids is ambiguous. Both rainforest and arid-adapted radiations probably started in the early Miocene. However, despite deep-lineage diversity in New Guinea rainforest habitats, overall species and ecological diversity is low when compared with more arid areas, with terrestrial taxa being strikingly absent.

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Booth, John D. "Habitat preferences and behaviour of newly settled Jasus edwardsii (Palinuridae)." Marine and Freshwater Research 52, no. 8 (2001): 1055. http://dx.doi.org/10.1071/mf01089.

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Any attempt to enhance production of rock lobsters by increasing survival at and soon after settlement, or by catching pueruli for on-growing or out-planting, requires knowledge of settlement behaviour and the habitat of settlers and young juveniles. I investigated biotic and physical factors important in habitat use by recently settled Jasus edwardsii in laboratory tank experiments. Both pueruli and first-instar juveniles sought shelter over and above conspecifics or any of the other marine life tested. They preferred conditioned refuges over those unconditioned, horizontal apertures over upward-facing vertical ones, and rough surfaces over smooth. Although some structurally complex seaweed and bryozoan species seemingly provide suitable refuge, they were less often used by the young lobsters than were hard-walled shelters. These results are generally consistent with the few field observations available and the results of experiments with collectors. Both pueruli and first-instar juveniles are capable of almost completely burying themselves in sand, but they are intolerant of deep silt. Any structures deployed to catch pueruli or to increase survival of recently settled J. edwardsii should ideally provide wellconditioned, firm but rough-walled, horizontal holes or crevices. The availability of such situations in nature may strongly influence lobster survival and abundance, and hence productivity.

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Noisette, Fanny, and Catriona Hurd. "Abiotic and biotic interactions in the diffusive boundary layer of kelp blades create a potential refuge from ocean acidification." Functional Ecology 32, no. 5 (March 20, 2018): 1329–42. http://dx.doi.org/10.1111/1365-2435.13067.

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Boiteau, G., A. Alyokhin, and D. N. Ferro. "The Colorado potato beetle in movement." Canadian Entomologist 135, no. 1 (February 2003): 1–22. http://dx.doi.org/10.4039/n02-008.

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AbstractThe recent introduction of the concept of refuge areas for the management of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera : Chrysomelidae), on resistant potato highlighted the existence of important gaps in our knowledge and understanding of this pest's movement within and between habitats. The objective of this review is to synthesize the information available for the benefit of crop managers and to identify subject areas in need of additional research. A traditional, somewhat encyclopedic, review of the old and recent literature on research methods, basics of flight and walking, as well as abiotic and biotic conditions for dispersal, revealed a considerable volume of information accumulated since the early 1900s. There is a consensus on the role of abiotic factors on flight and walking, but a better understanding of the biotic factors will be required before the variability of the dispersal response can be fully explained or predicted. Cybernetic models of orientation proposed in the literature were pulled together into a schematic representation of the orientation process in walking L. decemlineata. The model begins the integration of the different conditions and underlying suggested mechanisms responsible for the orientation of the walking beetle. There is remarkably little information on the orientation of potato beetles during flight. Finally, the seasonality of walking and flight dispersal is reviewed in relation to the host habitat and overwintering sites.

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Tangen, Brian A., Raymond G. Finocchiaro, Wesley E. Newton, and Charles F. Dahl. "Aquatic Vegetation and Invertebrate Communities of Big Stone National Wildlife Refuge." Journal of Fish and Wildlife Management 10, no. 1 (March 1, 2019): 277–94. http://dx.doi.org/10.3996/082018-jfwm-066.

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Abstract Observed degradation of aquatic systems at Big Stone National Wildlife Refuge, located in west-central Minnesota, have been associated with sediment-laden inflows from riverine systems. To support management, a study was conducted during 2013–2014 with overall goals of characterizing the aquatic invertebrate and vegetation communities of the Big Stone National Wildlife Refuge and exploring relations between these communities and various water-quality parameters. Sample sites were located along an observed vegetation gradient and assigned to three predetermined habitat zones for comparison purposes: upstream, transition, and downstream. Of the 12 species of aquatic vegetation that were identified, invasive narrowleaf cattail Typha angustifolia dominated the upstream zone (observed at >90% of sample locations), coontail Ceratophyllum demersum and narrowleaf cattail were most common in the transition zone (collected or observed at 100 and 83% of sample locations, respectively), and coontail and narrowleaf pondweed Potamogeton strictifolius were most common in the downstream zone (collected at 100 and 64% of sample locations, respectively). Measured values for the water-quality parameters varied among dates, reflecting the continually fluctuating nature of riverine systems. Based on general observations across sample dates, turbidity and dissolved oxygen concentrations were greatest in the upstream zone sample sites, while oxidation-reduction potential was greatest in the downstream zone sites. There were 115 unique aquatic invertebrate taxa identified to varying levels of taxonomic resolution. Results suggested that there were overall differences in invertebrate biomass among the sample dates, but that there were no strong trends among the sample zones. Aquatic invertebrates and vegetation communities, along with the water-quality parameters, varied temporally and showed irregular relations among the sample zones. These general observations emphasize the importance of temporally and spatially intensive sampling to account for natural variation. Moreover, short- and long-term streamflow and water-level information obtained for this study demonstrated substantial variability that must be considered when conducting biotic inventories and monitoring water quality, as well as when using such data to assess management options. Periodic monitoring of wetlands and associated streamflows, along with sediment loads and water quality of inflows, should allow Big Stone National Wildlife Refuge staff to identify habitat degradation and potential contributing factors, and to develop strategies to achieve specific management objectives and goals.

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Taira, D., EC Heery, LHL Loke, A. Teo, AG Bauman, and PA Todd. "Ecological engineering across organismal scales: trophic-mediated positive effects of microhabitat enhancement on fishes." Marine Ecology Progress Series 656 (December 10, 2020): 181–92. http://dx.doi.org/10.3354/meps13462.

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Retrofitting microhabitat features is a common ecological engineering technique for enhancing biodiversity and abundance of small, epilithic organisms on artificial shorelines by providing refuge spaces and/or ameliorating abiotic conditions. These features are typically too small to be utilised as refugia by larger, highly motile consumers such as fish, but they may affect these organisms through other mechanisms. This study sought to determine whether microhabitat enhancement units alter the fish abundance, richness and assemblage composition on tropical seawalls and explores possible underlying trophic mechanisms. We created 12 experimental plots consisting of 6 enhanced plots, each with 20 microhabitat enhancement tiles, and 6 control plots without tiles on intertidal seawalls at Pulau Hantu, an offshore island south of mainland Singapore. Benthic cover and fish assemblage were surveyed within each plot using photoquadrats and underwater video cameras, respectively, from April 2018 to February 2019. We found greater abundance and species richness and distinct assemblages of fish in the enhanced plots compared to the control plots. These differences were driven largely by an increase in both abundance and richness of fish species with epibenthic-feeding strategies and were significantly associated with higher biotic cover in the enhanced plots, especially epilithic algal matrix (EAM). Our results indicate that, in addition to facilitating epilithic organisms, microhabitat enhancement can provide food resources for epibenthic-feeding fishes, increase fish biodiversity, and alter fish assemblages in tropical urbanised shorelines.

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Bodharamik, Thavin, Waraporn Juntarajumnong, Chamnarn Apiwathnasorn, Sungsit Sungvornyothin, and Uraiwan Arunyawat. "Diversity Of Mosquito Species Ovipositing In Different Zones of Light Intensity Within Limestone Caves In Thailand." Journal of the American Mosquito Control Association 34, no. 3 (September 1, 2018): 182–89. http://dx.doi.org/10.2987/18-6742.1.

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ABSTRACT Climate change and human activity affect the geographical and annual distribution and population abundance of mosquitoes. As natural habitats are reduced, it is hypothesized that mosquitoes may seek refuge in more stable environments such as cave habitats. Therefore, we explored the species diversity of mosquitoes exploiting cave habitats in Thailand. Ten species belonging to 4 genera were collected, of which none were considered to be true cave-dwelling species (Troglobiont). The known cavernicolous species, Aedes cavaticus, was observed to oviposit outside of the cave and therefore should be categorized as a subtroglophilic species. Other species were also oviposited inside the cave but should be regarded as trogloxenic species. There was no clear association between environmental factors and mosquito abundance inside the 4 limestone caves, except for Ae. cavaticus, which was positively correlated with rainfall. This study indicates that different biotic or abiotic factors may be involved in mosquito oviposition site selection inside caves.

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Caillaux, Luis M., and Wolfgang B. Stotz. "Distribution and abundance of Rhynchocinetes typus (Crustacea: Decapoda), in different benthic community structures in northern Chile." Journal of the Marine Biological Association of the United Kingdom 83, no. 1 (January 10, 2003): 143–50. http://dx.doi.org/10.1017/s0025315403006908h.

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An evaluation was carried out on the distribution and abundance of the rock shrimp Rhynchocinetes typus in the inshore subtidal zone on the north-central coast of Chile. A number of different benthic community types occur in the region which have different degrees of spatial complexity provided by the primary substratum and by the biotic communities colonizing the substratum. Shrimp abundance was estimated in five different community types including shallow and deep ‘barren grounds’, low encrusting communities, erect suspension feeding associations, and kelp beds of Lessonia trabeculata. The abundance of shrimp was determined on three different types of primary substratum (stones, boulders, rock mass) within each community. Rhynchocinetes typus occurred in all the communities studied, showing the highest abundance on the deep barren grounds and lowest abundance on the shallow barren grounds. The shrimp was found to prefer the stony areas, as these offered the greatest degree of refuge. The abundance of predators was not significantly different among the different communities. However, a decline of abundance of predators was apparent over the deep barren grounds.

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Holienková, Barbora, and Zuzana Krumpálová. "EFFECTS OF URBANISM ON MALACOFAUNA (NITRA)." CBU International Conference Proceedings 4 (September 21, 2016): 257–61. http://dx.doi.org/10.12955/cbup.v4.766.

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Recently, the number of alien landscape species has dramatically increased, and this could be a serious threat, not only for native species but also in cases of outbreaks for farmers. Our objective was to examine the impact of the urban environment (positive or negative) on the diversity of native species; forecast biotic homogenization or diversification of urban fauna; and determine the extent to which each of the zones are affected by invasive species. To examine the effect of urbanization, we selected 16 areas (across three urban zones and one zone in the protected area for comparison) for this study in 2015 in Nitra. We found that snails in open locations had significantly greater species diversity and abundance of individuals than in closed locations. Slightly degraded areas had the most abundant snail species, but areas heavily disturbed had high species diversity and incidence of individuals. It appears that heavily disturbed areas are suitable as new types of refuge for snails, e.g., for Helix lucorum, which was recorded in Slovakia for the first time (numerically recorded at the railway station) in 2014.

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Tronstad, Lusha M., J. Joseph Giersch, Scott Hotaling, Debra S. Finn, Lydia Zeglin, Oliver J. Wilmot, and Rebecca J. Bixby. "A unique “icy seep” aquatic habitat in the high Teton Range: Potential refuge for biological assemblages imperiled by climate change." UW National Parks Service Research Station Annual Reports 39 (December 15, 2016): 64–72. http://dx.doi.org/10.13001/uwnpsrc.2016.5289.

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Alpine streams are threatened as meltwater sources diminish. We established baseline monitoring efforts of alpine streams in the Teton Range during 2015 by describing biotic and abiotic conditions of surface glacier and snowmelt streams. Our results indicated a third alpine stream type, icy seeps. Icy seeps are fed by subterranean ice melt, extremely cold but stable water temperature (summer mean <2°C), moderately high streambed stability (Pfankuch Index ~18-25), and relatively high specific conductivity (>50 μS cm-1). In 2016, we documented several icy seeps in the Teton massif, and our data suggest that they have the potential to serve as climate refugia for organisms and processes associated with extremely cold meltwater, due to the subterranean ice sources being more insulated from atmospheric conditions than surface glaciers and snowpack. Our 2016 work focused on locating icy seeps and documenting physical conditions, invertebrates, diatoms, and microbes in these alpine streams. We are processing the biological data, but microbial assemblages in icy seeps are similar to those found in streams fed by dwindling surface glacier ice. We are preparing to submit a paper about the microbial patterns, including how they compare to alpine streams representing comparable hydrological sources in Glacier National Park. Featured photo by Nicole Y-C on Unsplash. https://unsplash.com/photos/9XixVlnUCbk

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Delucchi, Carla M. "Comparison of community structure among streams with different temporal flow regimes." Canadian Journal of Zoology 66, no. 3 (March 1, 1988): 579–86. http://dx.doi.org/10.1139/z88-085.

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A study was conducted in four streams in the same watershed in New York to determine whether the benthic invertebrate community structure varied among streams with different temporal flow regimes. Timed kick samples were taken from 13 riffles and 4 pools once a month from June to November 1982. Riffle sites were classified according to temporal flow regime as permanent, intermittent (dry for less than 3 months), or dry (dry for over 3 months), and varied in size as a function of discharge. Ordination analysis (detrended correspondence analysis) showed that the structure of the benthic invertebrate communities in these streams was related not only to riffle permanence, but also to other abiotic and biotic parameters. Differences in community structure were greater between adjacent pools and riffles than between temporary and permanent riffles. Stream size, seasonal changes in taxa, how recently the riffle had dried, and the length of the dry period contributed to differences in community structure among riffles. It appears that differences in community structure between permanent and temporary riffles are minimized by generalized adaptations of stream benthos, such as high rates of migration, drought-resistant eggs, and the tendency to take refuge in the hyporheic zone.

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Cheng, Wei, Geng Sun, Lin-fang Du, Yan Wu, Qun-ying Zheng, Hong-xuan Zhang, Lin Liu, and Ning Wu. "Unpalatable weed Stellera chamaejasme L. provides biotic refuge for neighboring species and conserves plant diversity in overgrazing alpine meadows on the Tibetan Plateau in China." Journal of Mountain Science 11, no. 3 (May 2014): 746–54. http://dx.doi.org/10.1007/s11629-013-2729-y.

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Sgarzi, Serena, Sandra Brucet, Mireia Bartrons, Ignasi Arranz, Lluís Benejam, and Anna Badosa. "Factors Influencing Abundances and Population Size Structure of the Threatened and Endemic Cyprinodont Aphanius iberus in Mediterranean Brackish Ponds." Water 12, no. 11 (November 21, 2020): 3264. http://dx.doi.org/10.3390/w12113264.

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Aphanius iberus is an endemic cyprinodontoid fish species of Mediterranean ponds in danger of extinction. In this study, we studied some abiotic and biotic factors that can influence A. iberus’s size structure and density in Mediterranean brackish ponds. We sampled fish using fyke nets in 10 ponds of Empordà (Spain) during the spring season. Our results showed that a better ecological status (according to the Water Quality of Lentic and Shallow Ecosystems (QAELS) index), pond’s depth and pond’s isolation (reflected by an increase in total nitrogen) were related to larger individual sizes and more size-diverse populations. Increasing the salinity is known to help the euryhaline A. iberus acting as a refuge from competitors. Nevertheless, our results showed that higher conductivities had a negative effect on A. iberus’s size structure, leading to a decrease in the mean and maximum size of the fish. Fish abundance (expressed as captures per unit of effort (CPUE)) seemed to increase with increasing the pond’s depth and total nitrogen (the latter reflecting pond isolation). In conclusion, our results suggest that achieving a better pond ecological status may be important for the conservation of endangered A. iberus, because better size-structured populations (i.e., larger mean and average lengths) were found at higher water quality conditions.

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Litz, Marisa N. C., Robert L. Emmett, Paul J. Bentley, Andrew M. Claiborne, and Caren Barceló. "Biotic and abiotic factors influencing forage fish and pelagic nekton community in the Columbia River plume (USA) throughout the upwelling season 1999–2009." ICES Journal of Marine Science 71, no. 1 (June 19, 2013): 5–18. http://dx.doi.org/10.1093/icesjms/fst082.

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Abstract Litz, M. N. C., Emmett, R. L., Bentley, P. J., Claiborne, A. M., and Barceló, C. Biotic and abiotic factors influencing forage fish and pelagic nekton community in the Columbia River plume (USA) throughout the upwelling season 1999–2009. – ICES Journal of Marine Science, 71: . Large river plumes modify coastal environments and can impact production across multiple trophic levels. From 1999 to 2009, the assemblages of forage fish, predator fish, and other pelagic nekton were monitored in coastal waters associated with the Columbia River plume. Surveys were conducted at night to target vertically migrating species, and community structure evaluated to better understand ecological interactions. Distinct inshore and offshore communities were identified during spring and summer that were correlated with ocean temperature, salinity, plume volume, and upwelling intensity. Resident euryhaline forage fish species, such as smelts, anchovy, herring, market squid, juvenile salmon, and spiny dogfish, showed a high affinity for inshore habitat and the lower salinity plume during spring. Highly migratory species, such as sardine, piscivorous hake, sharks, and mackerels, were associated with warmer, saltier waters offshore, during strong upwelling periods in summer. Overall, our study of pelagic nekton revealed that temporal dynamics in abundance and community composition were associated with seasonal abiotic phenomenon, but not interannual, large-scale oceanographic processes. Forage fish assemblages differed seasonally and spatially from the assemblages of major piscivorous predators. This finding suggests a potential role of the plume as refuge for forage fish from predation by piscivorous fish in the northern California Current.

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Watson, Laurence H., Michael J. Cameron, and Fillemon Iifo. "Elephant herbivory of knob‐thorn ( Senegalia nigrescens ) and ivory palm ( Hyphaene petersiana ) in Bwabwata National Park, Caprivi, Namibia: The role of ivory palm as a biotic refuge." African Journal of Ecology 58, no. 1 (August 13, 2019): 14–22. http://dx.doi.org/10.1111/aje.12681.

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Fouquet, Antoine, Elodie A. Courtois, Daniel Baudain, Jucivaldo Dias Lima, Sergio Marques Souza, Brice P. Noonan, and Miguel T. Rodrigues. "The trans-riverine genetic structure of 28 Amazonian frog species is dependent on life history." Journal of Tropical Ecology 31, no. 4 (June 8, 2015): 361–73. http://dx.doi.org/10.1017/s0266467415000206.

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Abstract:Among the hypotheses formulated to explain the origin of Amazonian biodiversity, two (the riverine-barrier and the river-refuge hypotheses) focus on the role that rivers play as biotic barriers promoting speciation. However, empirical results have both supported and refuted these hypotheses. This is likely due, at least in part, to river-specific hydrologic characteristics and the biology of the focal species. The rivers of the Guiana Shield represent a model system because they have had more stable courses over time than those of the western Amazon Basin, where most tests of riverine barrier effects have taken place. We tested whether life-history traits (body size, habitat and larval development), expected to be important in determining dispersal ability, of 28 frog species are associated with genetic structure and genetic distances of individuals sampled from both banks of the Oyapock River. Thirteen of these species displayed genetic structure consistent with the river acting as a barrier to dispersal. Surprisingly, body size was not correlated with trans-riverine population structure. However, leaf-litter dwellers and species lacking free-living tadpoles were found to exhibit higher river-associated structure than open habitat/arboreal species and those with exotrophic tadpoles. These results demonstrate that rivers play an important role in structuring the genetic diversity of many frog species though the permeability of such riverine barriers is highly dependent on species-specific traits.

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Castro-Sanguino, C., YM Bozec, and PJ Mumby. "Dynamics of carbonate sediment production by Halimeda: implications for reef carbonate budgets." Marine Ecology Progress Series 639 (April 2, 2020): 91–106. http://dx.doi.org/10.3354/meps13265.

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Reef carbonate production and sediment generation are key processes for coral reef development and shoreline protection. The calcified green alga Halimeda is a major contributor of calcareous sediments, but rates of production and herbivory upon Halimeda are driven by biotic and environmental factors. Consequently, estimating rates of calcium carbonate (CaCO3) production and transformation into sediment requires the integration of Halimeda gains and losses across habitats and seasons, which is rarely considered in carbonate budgets. Using seasonal rates of recruitment, growth, senescence and herbivory derived from observations and manipulative experiments, we developed an individual-based model to quantify the annual cycle of Halimeda carbonate and sediment production at Heron Island, Great Barrier Reef. Halimeda population dynamics were simulated both within and outside branching Acropora canopies, which provide refuge from herbivory. Shelter from herbivory allowed larger Halimeda thalli to grow, leading to higher rates of carbonate accumulation (3.9 and 0.9 kg CaCO3 m-2 yr-1 within and outside Acropora canopies, respectively) and sediment production (2.5 versus 1.0 kg CaCO3 m-2 yr-1, respectively). Overall, 37% of the annual carbonate production was transformed into sediments through senescence (84%) and fish herbivory (16%), with important variations among seasons and habitats. Our model underlines that algal rates of carbonate production are likely to be underestimated if herbivory is not integrated into the carbonate budget, and reveals an important indirect pathway by which structurally complex coral habitats contribute to reef carbonate budgets, suggesting that coral losses due to climate change may lead to further declines in reef sediment production.

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Tonn, William M., and Cynthia A. Paszkowski. "Habitat use of the central mudminnow (Umbra limi) and yellow perch (Perca flavescens) in Umbra-Perca assemblages: the roles of competition, predation, and the abiotic environment." Canadian Journal of Zoology 65, no. 4 (April 1, 1987): 862–70. http://dx.doi.org/10.1139/z87-137.

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We compared spatial distributions and diel activity patterns of three fish populations (co-occurring central mudminnows and yellow perch, and a mudminnow population in a single-species assemblage) throughout the year in two small, northern Wisconsin dystrophic lakes. In winter, all three populations were more active offshore and during the day. During spring and summer–fall all were concentrated inshore, near the bottom, and were more active around dawn and dusk. Winter distributions appeared to be responses to abiotic conditions (ice cover and low oxygen availability); overall patterns during open-water periods appeared to be linked to prey availability (e.g., chironomid emergences). Although the three populations were generally similar, some aspects of habitat use differed between species, between lakes, or between dominant and subdominant populations, with the direction of differences varying seasonally. The yellow perch population was recovering from a size-selective winterkill and between spring and summer underwent an ontogenetic niche shift, first being competitors with mudminnows, then becoming predators on mudminnows. Mudminnows did not alter their vertical or diel activity patterns in the presence of these predatory perch. They did become more concentrated inshore in summer–fall, near structural refuge provided by the bog mat, and, unlike the other two populations, failed to shift their activities offshore at twilight. Our study suggested that a simple habitat in the study lakes contributed both to overall similarities in habitat use and strong interactions between co-occurring populations. However, the ecological flexibility demonstrated by mudminnows may prevent their total exclusion from lakes inhabited by perch and allow them to respond to changing biotic environments.

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Tronstad, Lusha M., J. Joseph Giersch, Scott Hotaling, Alisha A. Shah, Lydia H. Zeglin, Rebecca J. Bixby, H. Arthur Woods, and Debra S. Finn. "Long-term alpine stream monitoring in the Teton Range: Investigating multi-year patterns and thermal physiology." UW National Parks Service Research Station Annual Reports 42 (December 15, 2019): 97–103. http://dx.doi.org/10.13001/uwnpsrc.2019.5747.

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Alpine streams and the biotic communities they contain are imperiled worldwide due to climate warming and the rapid decline of ice. The loss of glaciers and permanent snowpack may drive local populations to extinction, especially organisms with narrow habitat tolerances. We have been monitoring alpine streams in the Teton Range since 2015 that originate from three hydrological sources: surface glaciers, snowfields, or subterranean ice (e.g., rock glaciers). We call these stream types glacier-fed, snowmelt-fed, and icy seeps, respectively. We hypothesize that icy seeps may persist on the landscape longer than other hydrologic sources and that these features may act as a refuge for cold-adapted organisms such as the stoneflies Zapada glacier and Lednia tetonica. In November 2019, Z. glacier and a sister species of L. tetonica, Lednia tumana, were listed under the U.S. Endangered Species Act. This decision was based in part on work funded by the UW-NPS and highlights the pressing nature of our efforts. In 2019, we collected a 5th year of long-term data to begin investigating multi-year signals in the data. Our second 2019 objective was to further explore how thermal regimes affect tolerance of potentially imperiled insects. Because our annual data collection occurs in late summer with sample processing and analysis extending into the following year, this report will be a broad update on the project as whole, rather than 2019-specific. Through long-term monitoring of streams from different hydrological sources, we are building a dataset that will allow us to understand changes as air temperatures warm and permanent ice is lost in the alpine zone. Featured photo by Nicole Y-C on Unsplash. https://unsplash.com/photos/9XixVlnUCbk

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Calle-Rendón, Bayron R., Mika Peck, Sara E. Bennett, Citlalli Morelos-Juarez, and Felipe Alfonso. "Comparison of forest regeneration in two sites with different primate abundances in Northwestern Ecuador." Revista de Biología Tropical 64, no. 2 (May 13, 2016): 493. http://dx.doi.org/10.15517/rbt.v64i2.18415.

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There is increasing evidence that large-bodied primates play important roles as seed dispersers and in the maintenance of tree diversity in forest ecosystems. In this study we compared forest regeneration at two sites with differing primate abundances in the Ecuadorian Chocoan rainforest. We predicted: (1) significant differences in primate abundance between the two sites; (2) higher understory tree species richness and density at the site with greater primate abundance; (3) the site with lower primate abundance characterized by tree species dispersed by non-primate biotic agents and/or abiotic factors. We compared two sites, Tesoro Escondido (TE) a campesino cooperative, and the El Pambilar (EP) wildlife refuge that both maintain populations of mantled howler monkey (Alouatta palliata), the brown-headed spider monkey (Ateles fusciceps fusciceps) and the capuchin monkey (Cebus capucinus). We characterized canopy structure by point-quadrant sampling, determined primate abundance and sampled seedlings/saplings in 1 m2 plots, classifying tree species based on three dispersal syndromes: adapted for primate dispersal, dispersed by other biological agents, and abiotic dispersal. We compared sites in terms of primate abundance (groups and individuals observed per day) and regeneration characteristics (overall density, species richness, and dispersal syndrome). We carried out within site comparisons and constructed understory tree species accumulation curves. Overall the forests were structurally similar - with significantly higher densities of A. f. fusciceps at TE. Encounter rates for the other two primate species were similar at both sites. Understory tree density and species richness was significantly higher in TE with no stabilization of tree species accumulation curves. The species accumulation curve for understory trees at EP stabilized. Higher densities and species richness of primate dispersed tree species were observed at TE, with non-primate biotically dispersed tree species the dominant dispersal syndrome at both sites. Our observations are consistent with those from other studies investigating the role of large-bodied frugivorous primates in forest regeneration, and point to a general pattern: future lowland tropical forest tree diversity depends on maintaining robust populations of large primate species in these systems. It is highly probable that the maintenance of high levels of tree diversity in Chocoan rainforests is dependent on the conservation of its largest resident primate, the critically endangered brown-headed spider monkey (A. f. fusciceps).

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Ackerly, David D., Matthew M. Kling, Matthew L. Clark, Prahlad Papper, Meagan F. Oldfather, Alan L. Flint, and Lorraine E. Flint. "Topoclimates, refugia, and biotic responses to climate change." Frontiers in Ecology and the Environment 18, no. 5 (June 2020): 288–97. http://dx.doi.org/10.1002/fee.2204.

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Jha, Shalene, Christopher M. Bacon, Stacy M. Philpott, V. Ernesto Méndez, Peter Läderach, and Robert A. Rice. "Shade Coffee: Update on a Disappearing Refuge for Biodiversity." BioScience 64, no. 5 (April 14, 2014): 416–28. http://dx.doi.org/10.1093/biosci/biu038.

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Clements, Cody S., and Mark E. Hay. "Competitors as accomplices: seaweed competitors hide corals from predatory sea stars." Proceedings of the Royal Society B: Biological Sciences 282, no. 1814 (September 7, 2015): 20150714. http://dx.doi.org/10.1098/rspb.2015.0714.

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Indirect biotic effects arising from multispecies interactions can alter the structure and function of ecological communities—often in surprising ways that can vary in direction and magnitude. On Pacific coral reefs, predation by the crown-of-thorns sea star, Acanthaster planci , is associated with broad-scale losses of coral cover and increases of macroalgal cover. Macroalgal blooms increase coral–macroalgal competition and can generate further coral decline. However, using a combination of manipulative field experiments and observations, we demonstrate that macroalgae, such as Sargassum polycystum , produce associational refuges for corals and dramatically reduce their consumption by Acanthaster . Thus, as Acanthaster densities increase, macroalgae can become coral mutualists, despite being competitors that significantly suppress coral growth. Field feeding experiments revealed that the protective effects of macroalgae were strong enough to cause Acanthaster to consume low-preference corals instead of high-preference corals surrounded by macroalgae. This highlights the context-dependent nature of coral–algal interactions when consumers are common. Macroalgal creation of associational refuges from Acanthaster predation may have important implications for the structure, function and resilience of reef communities subject to an increasing number of biotic disturbances.

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Fischman, Robert L., Vicky J. Meretsky, Alexei Babko, Michael Kennedy, Lei Liu, Michelle Robinson, and Susan Wambugu. "Planning for Adaptation to Climate Change: Lessons from the US National Wildlife Refuge System." BioScience 64, no. 11 (October 7, 2014): 993–1005. http://dx.doi.org/10.1093/biosci/biu160.

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Dolby, Greer A., Ryan Hechinger, Ryan A. Ellingson, Lloyd T. Findley, Julio Lorda, and David K. Jacobs. "Sea-level driven glacial-age refugia and post-glacial mixing on subtropical coasts, a palaeohabitat and genetic study." Proceedings of the Royal Society B: Biological Sciences 283, no. 1843 (November 30, 2016): 20161571. http://dx.doi.org/10.1098/rspb.2016.1571.

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Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify and assess a sea-level-driven recolonization process following the Last Glacial Maximum (LGM). Our palaeohabitat modelling reveals dramatic changes in estuarine habitat distribution along the coast of California (USA) and Baja California (Mexico). At the LGM (approx. 20 kya), when sea level was approximately 130 m lower, the palaeo-shoreline was too steep for tidal estuarine habitat formation, eliminating this habitat type from regions where it is currently most abundant, and limiting such estuaries to a northern and a southern refugium separated by 1000 km. We assess the recolonization of estuaries formed during post-LGM sea-level rise through examination of refugium-associated alleles and approximate Bayesian computation in three species of estuarine fishes. Results reveal sourcing of modern populations from both refugia, which admix in the newly formed habitat between the refuges. We infer a dramatic peak in habitat area between 15 and 10 kya with subsequent decline. Overall, this approach revealed a previously undocumented dynamic and integrated relationship between sea-level change, coastal processes and population genetics. These results extend glacial refugial dynamics to unglaciated subtropical coasts and have significant implications for biotic response to predicted sea-level rise.

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Mulanda Aura, Christopher, Chrisphine S. Nyamweya, James M. Njiru, Reuben Omondi, Julius Manyala, Safina Musa, Horace Owiti, et al. "Using the Multi-metric Index of Biotic Integrity methodological approach to determine the major river catchment that most pollutes a lake." Aquatic Ecosystem Health & Management 24, no. 1 (January 2, 2021): 12–20. http://dx.doi.org/10.14321/aehm.024.01.04.

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Abstract We present the Multi-metric Index of Biotic Integrity methodological approach that allows for the ranking of major river catchments based on pollution status in the Kenyan portion of Lake Victoria, Africa. The study has a broader applicability to all of Lake Victoria, other African Great Lakes, and all lakes that have riverine discharge. The method presented utilizes water quality and environmental data, local knowledge, and pre-existing literature. The parameters considered were sampled from 2016 to 2018 during the dry season (July sampling) and the wet season (March sampling). Separation power of Mann-Whitney U test (p < 0.05) qualified 11 discriminant metrics for both macroinvertebrate and fish samples into the scoring system of 1, 3 and 5 in the formulation of final Multi-metric Index of Biotic Integrity methodological approach. Rivers in the northern section had lower Multi-metric Index of Biotic Integrity methodological approach scores, as compared to southern counterparts. The Multi-metric Index of Biotic Integrity methodological approach ranking herein was validated by community perceptions on pollution levels. River Nzoia catchment emerged as the most polluted, followed by River Yala, River Kuja, and Sondu-Miriu. Siltation, domestic washing, litter and refuse emerged as the main agents of pollution. Management authorities ought to reinforce a balanced utilization of the vital water resources to minimize future impacts, and promote catchment wide practices that ensure ecological health sustainability of the lake ecosystem.

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Anderson, Alex S., April E. Reside, Jeremy J. VanDerWal, Luke P. Shoo, Richard G. Pearson, and Stephen E. Williams. "Immigrants and refugees: the importance of dispersal in mediating biotic attrition under climate change." Global Change Biology 18, no. 7 (April 18, 2012): 2126–34. http://dx.doi.org/10.1111/j.1365-2486.2012.02683.x.

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Mota‐Ferreira, Mário, and Pedro Beja. "Combining geostatistical and biotic interaction model to predict amphibian refuges under crayfish invasion across dendritic stream networks." Diversity and Distributions 26, no. 6 (April 14, 2020): 699–714. http://dx.doi.org/10.1111/ddi.13047.

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Lescano, María Natalia, Alejandro G. Farji-Brener, Ernesto Gianoli, and Tomás A. Carlo. "Bottom-up effects may not reach the top: the influence of ant–aphid interactions on the spread of soil disturbances through trophic chains." Proceedings of the Royal Society B: Biological Sciences 279, no. 1743 (June 20, 2012): 3779–87. http://dx.doi.org/10.1098/rspb.2012.1066.

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Soil disturbances that increase nutrient availability may trigger bottom-up cascading effects along trophic chains. However, the strength and sign of these effects may depend on attributes of the interacting species. Here, we studied the effects of nutrient-rich refuse dumps of the leaf-cutting ant, Acromyrmex lobicornis , on the food chain composed of thistles, aphids, tending ants and aphid natural enemies. Using stable isotopes tracers, we show that the nitrogen accumulated in refuse dumps propagates upward through the studied food chain. Thistles growing on refuse dumps had greater biomass and higher aphid density than those growing in adjacent soil. These modifications did not affect the structure of the tending ant assemblage, but were associated with increased ant activity. In contrast to the expectations under the typical bottom-up cascade effect, the increase in aphid abundance did not positively impact on aphid natural enemies. This pattern may be explained by both an increased activity of tending ants, which defend aphids against their natural enemies, and the low capacity of aphid natural enemies to show numerical or functional responses to increased aphid density. Our results illustrate how biotic interactions and the response capacity of top predators could disrupt bottom-up cascades triggered by disturbances that increase resource availability.

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Olukanni, O. D., A. A. Osuntoki, and G. O. Gbenle. "Decolourization of Azo Dyes by a Strain of Micrococcus Isolated from a Refuse Dump Soil." Biotechnology(Faisalabad) 8, no. 4 (September 15, 2009): 442–48. http://dx.doi.org/10.3923/biotech.2009.442.448.

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REYAHI-KHORAM, MAHDI. "The threates on the biodiversity of Bisotun Wildlife Refuge and Bisotun Protected Area (BPA & BWR) in the west region of Iran." Biodiversitas, Journal of Biological Diversity 15, no. 1 (April 1, 2014): 67–74. http://dx.doi.org/10.13057/biodiv/d150110.

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Goeden, R. D., and L. T. Kok. "COMMENTS ON A PROPOSED “NEW” APPROACH FOR SELECTING AGENTS FOR THE BIOLOGICAL CONTROL OF WEEDS." Canadian Entomologist 118, no. 1 (January 1986): 51–58. http://dx.doi.org/10.4039/ent11851-1.

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AbstractThe “new approach” to selecting biological control agents, as proposed by Hokkanen and Pimentel in 1984, through the use of new exploiter–victim associations is inappropriate for the biological control of weeds because of certain misconceptions in their method. Examples of biological control of weeds cited in their analysis were biased towards cactaceous insects, and cacti are not representative of target weeds. Several of their “new” associations were inaccurate. These inaccuracies are discussed and additional examples are provided to refute the proposed method. Contrary to the recommendation of Hokkanen and Pimentel, new exploiter-victim associations offer limited opportunities for biological control of non-cactaceous weeds with insects, and should not be used as the preferred method in selecting biotic agents for the biological control of weeds.

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Kranzfelder, Petra, and Leonard C. Ferrington, Jr. "Chironomidae (Diptera) species diversity of estuaries across a land use gradient on the Caribbean coast of Costa Rica." Revista de Biología Tropical 66, no. 3 (July 4, 2018): 1118. http://dx.doi.org/10.15517/rbt.v66i3.31927.

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The family Chironomidae (Diptera) is the most widely distributed, most diverse, and often the most abundant of all families of benthic macroinvertebrates in aquatic ecosystems, including estuaries and other coastal marine ecosystems. Chironomid assemblages are likely to provide a useful measure of biotic integrity in estuaries of Costa Rica, which lack an intensive estuarine bioassessment tool to support environmental monitoring and regulatory programs. We characterized the taxonomic composition of Chironomidae, tested a Chironomidae Index of Biotic Integrity (CIBI) developed from extrinsic pollution tolerance values for its efficacy in evaluating the surface water quality and physical habitat, and made recommendations for increasing the sensitivity of the CIBI to detect differing degrees of stress across a range of estuaries in Costa Rica. Specifically, we selected nine estuaries within six different watersheds across a land use gradient located on the Caribbean coast of Costa Rica and collected Chironomidae surface-floating pupal exuviae (SFPE) samples biannually for two consecutive years (July 2012, Jan. 2013, July 2013, Jan. 2014). We identified 228 morphospecies and 70 genera from 17 071 Chironomidae pupal exuviae collected from nine estuaries, which ranked in the following order from lowest to highest biotic integrity based on CIBI scores: Estero Negro, Laguna Cuatro, Laguna Jalova, Laguna del Tortuguero, Río Parismina, Laguna Barra del Colorado, Río Pacuare, Río Bananito, and Río Estrella. The CIBI successfully differentiated between estuaries with poor versus good biotic integrity, indicating that CIBI could be used to evaluate the surface water quality and physical habitat of Costa Rican estuaries. We recommend that future studies refine our approach by developing regionally accurate genus and corresponding species-level tolerance values to improve the sensitivity of the CIBI for biological monitoring of Costa Rican estuaries.

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Leonard, Steven W. J., Andrew F. Bennett, and Michael F. Clarke. "Determinants of the occurrence of unburnt forest patches: Potential biotic refuges within a large, intense wildfire in south-eastern Australia." Forest Ecology and Management 314 (February 2014): 85–93. http://dx.doi.org/10.1016/j.foreco.2013.11.036.

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B. Walker, Ryan, Jonathan D. Coop, William M. Downing, Meg A. Krawchuk, Sparkle L. Malone, and Garrett W. Meigs. "How Much Forest Persists Through Fire? High-Resolution Mapping of Tree Cover to Characterize the Abundance and Spatial Pattern of Fire Refugia Across Mosaics of Burn Severity." Forests 10, no. 9 (September 8, 2019): 782. http://dx.doi.org/10.3390/f10090782.

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Wildfires in forest ecosystems produce landscape mosaics that include relatively unaffected areas, termed fire refugia. These patches of persistent forest cover can support fire-sensitive species and the biotic legacies important for post-fire forest recovery, yet little is known about their abundance and distribution within fire perimeters. Readily accessible 30-m resolution satellite imagery and derived burn severity products are commonly employed to characterize post-fire landscapes; however, coarse image resolution, generalized burn severity thresholds, and other limitations can constrain accurate representation of fire refugia. This study quantifies the abundance and pattern of fire refugia within 10 fires occurring in ponderosa pine and dry mixed-conifer forests between 2000 and 2003. We developed high-resolution maps of post-fire landscapes using semi-automated, object-based classification of 1-m aerial imagery, conducted imagery- and field-based accuracy assessments, and contrasted these with Landsat-derived burn severity metrics. Fire refugia area within burn perimeters ranged from 20% to 57%. Refugia proportion generally decreased with increasing Landsat-derived burn severity, but still accounted for 3–12% of areas classified as high severity. Patch size ranged from 1-m2 isolated trees to nearly 8000 ha, and median patch size was 0.01 ha—substantially smaller than a 30-m Landsat pixel. Patch size was negatively related to burn severity; distance to fire refugia from open areas was positively related to burn severity. Finally, optimized thresholds of 30-m post-fire normalized burn ratio (NBR) and relative differenced normalized burn ratio (RdNBR) delineated fire refugia with an accuracy of 77% when validated against the 1-m resolution maps. Estimations of fire refugia abundance based on Landsat-derived burn severity metrics are unlikely to detect small, isolated fire refugia patches. Finer-resolution maps can improve understanding of the distribution of forest legacies and inform post-fire management activities including reforestation and treatments.

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Ribas, Camila C., Alexandre Aleixo, Afonso C. R. Nogueira, Cristina Y. Miyaki, and Joel Cracraft. "A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years." Proceedings of the Royal Society B: Biological Sciences 279, no. 1729 (July 27, 2011): 681–89. http://dx.doi.org/10.1098/rspb.2011.1120.

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Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia ), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen ‘complete’ time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0–2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia , in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia.

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Lacasse, Sylvain, and Pierre Magnan. "Biotic and Abiotic Determinants of the Diet of Brook Trout, Salvelinus fontinalis, in Lakes of the Laurentian Shield." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 5 (May 1, 1992): 1001–9. http://dx.doi.org/10.1139/f92-112.

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From a survey of 12 lakes containing brook trout, Salvelinus fontinalis, 12 lakes containing brook trout and creek chub, Semotilus atromaculatus, and 13 lakes containing brook trout and white sucker, Catostomus commersoni, we built seven multiple linear regression models to account for the mean percent weight of different prey categories in the diet of brook trout. Presence of chub and sucker, zooplankton community structure, sampling date, morphoedaphic index, and the importance of rock outcrops accounted for 88% of the variation in weight of zoobenthos eaten by trout, which was the preferred prey in allopatry. Thirty percent of the variation in weight of zooplankton eaten by trout was explained by the importance of macrophytes and other refuges for fish. Models for amphipods, dipteran pupae, swimming insects, terrestrial insects, and prey-fish explained between 36 and 63% of the variation. The presence of white sucker or an index of their impact (mean length or density of Cladocera) and the characteristics of littoral habitats appeared in six of seven models. Littorasl habitats seemed particularly determinant for the inclusion of prey-fish in the diet, more prey-fish being eaten when regufes were abundant. Variables related to lake morphometry and physicochemistry appeared less regularly in the models.

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AMATTA, EMILCE, LUIS A. CALCATERRA, and STELLA M. GIANNONI. "Ant species (Hymenoptera: Formicidae) in the three forests of the Ischigualasto Provincial Park, a protected area of the Monte Desert, Argentina." Biodiversitas Journal of Biological Diversity 19, no. 3 (May 1, 2018): 831–39. http://dx.doi.org/10.13057/biodiv/d190311.

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Amatta E, Calcaterra LA, Giannoni SM. 2018. Ant species (Hymenoptera: Formicidae) in the three forests of the Ischigualasto Provincial Park, a protected area of the Monte Desert, Argentina. Biodiversitas 19: 831-839. Deforestation and overgrazing mediated by the humans have caused a serious process of desertification in the Argentine Monte Desert, which threats biodiversity of this ecosystem. Forests provide important resources and refuge for animal species, such as ants. The objective of this work was to survey the ant fauna of dryland forests of Ischigualasto Provincial Park, a protected area located in the hyper-arid Monte Desert ecoregion in the province of San Juan, Argentina. Ant species were surveyed in summer in three types of forests (Prosopis, Ramorinoa and Bulnesia forests), using a combination of sampling methods: pitfall-traps, baiting, and hand collection. A total of 33 ant species were collected, of which 17 are new records for the Monte Desert and Dry Chaco and 24 for the San Juan province. The species richness is within the range reported for other Argentine desert and semi-desert areas. Prosopis forest was the richest with 32 species (24 exclusive), followed by Ramorinoa and Bulnesia forests with 11 and 4 species, respectively. This study contributes to improve the knowledge of ant fauna in desert habitats of the world, especially those inhabiting Prosopis forests, which are the most important ant diversity hotspots within the hyper-arid desert.

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Rhodes, Melissa C. "Comparative physiology of suspension feeding in living articulate brachiopods and bivalves - implications for large-scale evolutionary patterns." Paleontological Society Special Publications 6 (1992): 244. http://dx.doi.org/10.1017/s2475262200008042.

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The hypothesis that biotic interactions have escalated over geologic time suggests that taxonomic groups such as bivalves, which developed representatives with high-energy life habits, preempted resources and drove “obsolete” low-energy groups, such as articulate brachiopods, into ecological refugia. Articulates had been the dominant benthos in a broad range of Paleozoic habitats. Modern refugia include areas of darkness and low primary productivity, such as fjords, caves, and polar regions. If the escalation hypothesis is true, then the modern articulates concentrated in these habitats should have extremely low energy budgets. The more energetic bivalves should be abundant higher in the photic zone and have higher energy budgets.The equation Consumption = Growth (metabolizing tissue) + Reproduction + Respiration + Faeces + Excreta (nitrogenous) describes the energy balance in an organism. Energy acquisition is a critical factor for the persistance of individuals and species. Scaling equations relating particle filtration rates (consumption) to tissue mass were developed experimentally for two northern and two southern hemisphere species of brachiopods. Similar equations were developed for a northern and a southern hemisphere mussel species. The scaling equations allow correction for size differences which would otherwise confound physiological comparisons between species. Both northern and southern hemisphere brachiopod species were collected from deep, dark fjords or soft bottom habitats with Paleozoic style faunas. The mussels were collected from the same areas, but occurred higher in the photic zone.Results indicate that the articulate brachiopods have a significantly lower ability to collect food particles from the water than do the mussels, for animals of similar body mass. These results support the hypothesis that escalated biotic interactions account, in part, for the ecological replacement of the formerly dominant Paleozoic articulate brachiopods by Mesozoic and Recent suspension-feeding bivalves.

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Leigh, Catherine, Fran Sheldon, Richard T. Kingsford, and Angela H. Arthington. "Sequential floods drive 'booms' and wetland persistence in dryland rivers: a synthesis." Marine and Freshwater Research 61, no. 8 (2010): 896. http://dx.doi.org/10.1071/mf10106.

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Flow is a key driver regulating processes and diversity in river systems across a range of temporal and spatial scales. In dryland rivers, variability in the timing and scale of floods has specific ecological significance, playing a major role in sustaining biotic diversity across the river-floodplain mosaic. However, longitudinal effects of floods are equally important, delivering water downstream through channels and wetland complexes. Interaction among spatially distributed wetlands, their connecting channel and floodplain geomorphology and the temporally variable flow events not only creates the spatial complexity in dryland rivers but also determines temporal persistence of wetlands. These act as hydrological ‘sponges’, absorbing water from upstream and needing to fill before releasing water downstream. Sequential high flow events are essential for the ecological persistence of riverine wetlands and the transmission of flows further downstream through the channel network. These flood sequences maintain aquatic refugia and drive booms in productivity sustaining aquatic and terrestrial biota over large spatial and temporal scales. Disrupting the sequence, with modified flow regimes and water removal for diversion (e.g. irrigation), significantly reduces the opportunity for wetland replenishment. As a result, the benefits of sequential flooding to the wetland ‘sponges’ and their biotic communities will be lost.

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Butler, Jack, and Jerrold Dodd. "Characterization of Relict Communities For Monitoring Park Ecosystems in Glen Canyon National Recreation Area." UW National Parks Service Research Station Annual Reports 13 (January 1, 1989): 67–69. http://dx.doi.org/10.13001/uwnpsrc.1989.2785.

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Grazing by domestic livestock is authorized on the Glen Canyon National Recreation Area and occurs on about 80% of the NRA lands. Concern over competing land uses has generated considerable interest in the direct and indirect effects of grazing on community structure and function (Kleiner and Harper 1972, 1977, Loope 1977, Jefferies and Klopatek 1987). The primary objectives of this study are to: (1) identify and evaluate the abiotic and biotic factors influencing the stucture and species composition of relict and grazed pinyonÂjuniper, black brush ricegrass, and ricegrass grassland communities, and (2) select, refine and validate a system that can be used to field monitor condition and trend of relict and grazed communities.

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Burrows, Neil D. "Fire dependency of a rock-outcrop plant Calothamnus rupestris (Myrtaceae) and implications for managing fire in south-western Australian forests." Australian Journal of Botany 61, no. 2 (2013): 81. http://dx.doi.org/10.1071/bt12240.

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Granite outcrops embedded in south-western Australian forests provide habitat for unique biotic assemblages and refugia for fire-sensitive taxa. Discontinuous vegetation and natural barriers to fire spread enable outcrops to function as fire refugia, provided fires in the surrounding forest are not of high intensity. In Summer 2003, lightning started a fire in jarrah forest that had not been burnt for almost 20 years. The high-intensity fire burned the vegetation on Mount Cooke, a large granite outcrop, providing an opportunity to study the response of Calothamnus rupestris Schauer, a fire-sensitive serotinous plant. The population was killed by the fire, but readily regenerated from seed stored in woody capsules. The post-fire population reached maturity after ~7.5 years, whereas the seed bank is unlikely to recover to the pre-fire level until ~14 years. The likelihood of intense forest wildfires affecting outcrop communities can be reduced by frequent low-intensity prescribed burning in the surrounding forests to reduce fuel hazard and quantity. Low-intensity forest fires are unlikely to be lethal to sensitive granite-outcrop communities.

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Pratt, Thomas C., and Michael G. Fox. "Biotic influences on habitat selection by young-of-year walleye (Stizostedion vitreum) in the demersal stage." Canadian Journal of Fisheries and Aquatic Sciences 58, no. 6 (June 1, 2001): 1058–69. http://dx.doi.org/10.1139/f01-054.

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The influence of prey availability and predation risk on the distribution of young-of-year (YOY) walleye (Stizostedion vitreum) was investigated by comparing species associations with the relative abundance of YOY walleye across nine habitat types using an underwater visual assessment technique. During the early demersal period (mid-June to mid-July), YOY walleye were found primarily in areas of high macrophyte cover at 25 m depth. YOY walleye abundance was positively correlated with the abundance of prey fishes at this time. YOY walleye shifted to low-cover, shallow areas during the late demersal period (mid-July to late August), and the significant prey associations disappeared. Although the selected habitats are considered to have low predation risk, the distribution of YOY walleye was not related to our index of predator abundance in either time period. YOY walleye were not observed in three of the nine habitat types, suggesting that active habitat selection was occurring. High macrophyte cover and prey availability appear to be the major factors influencing habitat selection during the early demersal period. Although our results do not demonstrate the functional significance of the shift of YOY walleye into shallow water, we hypothesize that these habitats are selected as refugia from particular predators such as adult walleye.

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Reid, Michael A., Martin C. Thoms, Stephen Chilcott, and Kathryn Fitzsimmons. "Sedimentation in dryland river waterholes: a threat to aquatic refugia?" Marine and Freshwater Research 68, no. 4 (2017): 668. http://dx.doi.org/10.1071/mf15451.

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In dryland river systems subject to prolonged low and no flow periods, waterholes, or sections of river channel that are deep relative to the rest of the channel and that retain water for longer periods of no flow, provide refugia for aquatic biota and hence are critical to the resilience of aquatic ecosystems. This study examined physical, chemical and bio-stratigraphy in refugial waterholes situated along four distributaries of the Lower Balonne River system in semi-arid Australia. In doing so we reconstructed environmental histories for the waterholes, calculated how sedimentation rates have changed in response to land use change over the past two centuries, and assessed whether they are threatened by increased sedimentation through potential effects on waterhole depth and hence persistence times and habitat quality. Our study found that sedimentation rates have increased substantially since European settlement, most likely in response to removal of groundcover by grazers. The increased sediment accumulation rates are estimated to have reduced persistence times during low and no flow periods of the waterholes by 2–4 months. Despite evidence from other similar systems in Australia that increased influx of sediment coincided with loss of submerged macrophytes, stratigraphic records of preserved pollen and diatoms did not provide consistent evidence of biotic or habitat quality changes within the waterholes associated with European settlement.

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ISMAIL, SITI NORASIKIN, MUZZALIFAH ABD HAMID, and MASHHOR MANSOR. "Ecological correlation between aquatic vegetation and freshwater fish populations in Perak River, Malaysia." Biodiversitas Journal of Biological Diversity 19, no. 1 (January 1, 2018): 279–84. http://dx.doi.org/10.13057/biodiv/d190138.

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Ismail SN, Abd Hamid M, Mansor M. 2018. Ecology, diversity and seasonal distribution of wild mushrooms in a Nigerian tropical forest reserve. Biodiversitas 19: 279-284. Aquatic plants play a crucial role in an aquatic ecosystem partly because these plant communities provide suitable habitats and food items to other aquatic organisms especially fish. Many fish communities use vegetation as breeding sites, nurseries and refuges for their juveniles. Therefore, this study was conducted to provide baseline data on the correlation between the aquatic plants and freshwater fishes in Perak River. Based on the findings, the abundance of aquatic plant influences the growth and health of the fish. Habitats with moderate amounts of aquatic vegetation provide the optimal environment for many fish and hence, increase the fish diversity, feeding, growth, and reproduction. In contrast, both limited and excessive vegetation may decrease fish growth rates at 75% to 85% of plant community coverage. The recent trip along the Perak discloses the presence of these aquatic plants at certain habitats. There is a positive correlation between aquatic plants and freshwater fish. The association between aquatic plants and fish assemblages has been documented in scientific studies with the conclusion that moderate plant densities could enhance the fish diversity, feeding, growth, and reproduction.

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Tronstad, Lusha, J. Joseph Giersch, Scott Hotaling, Lydia Zeglin, Oliver Wilmot, Rebecca J. Bixby, and Debra S. Finn. "Establishing a long-term monitoring network for assessing potential climatic refugia in cold alpine streams." UW National Parks Service Research Station Annual Reports 40 (December 15, 2017): 69–78. http://dx.doi.org/10.13001/uwnpsrc.2017.5581.

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Managing landscapes to maintain climate refugia is likely the best strategy to promote persistence of temperature-sensitive species with limited dispersal capacity. Rare, cold-stenothermic taxa occupy mosaic mountain stream networks due largely to hydrological source heterogeneity. We collected environmental and biological data from alpine streams in the Teton Range, Wyoming representing runoff from snowpack (N=3), glaciers (N=4) and subterranean ice (N=4), every summer from 2015-2017. We quantified differences in habitat among the streams according to a glaciality index that included bed stability, suspended solids, temperature and conductivity, and by comparing annual water temperature profiles for each stream. We measured to what degree macroinvertebrate and diatom assemblages varied by stream type. Abiotic and biotic characteristics appeared to differ among sources. Notably, streams fed by subterranean ice (icy seeps) maintained extremely low (mean <2°C) and stable water temperature. Rare, cold-stenothermic stonefly species (Zapada glacier and Lednia tetonica) were indicators for, although not exclusive to, icy seeps. Icy seeps and their sources may be refugia for temperature-sensitive taxa, as the subsurface ice is more insulated from warmer air temperatures. Featured photo by Nicole Y-C on Unsplash. https://unsplash.com/photos/9XixVlnUCbk

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Conran, John G., William G. Lee, Daphne E. Lee, Jennifer M. Bannister, and Uwe Kaulfuss. "Reproductive niche conservatism in the isolated New Zealand flora over 23 million years." Biology Letters 10, no. 10 (October 2014): 20140647. http://dx.doi.org/10.1098/rsbl.2014.0647.

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The temporal stability of plant reproductive features on islands has rarely been tested. Using flowers, fruits/cones and seeds from a well-dated (23 Ma) Miocene Lagerstätte in New Zealand, we show that across 23 families and 30 genera of forest angiosperms and conifers, reproductive features have remained constant for more than 20 Myr. Insect-, wind- and bird-pollinated flowers and wind- and bird-dispersed diaspores all indicate remarkable reproductive niche conservatism, despite widespread environmental and biotic change. In the past 10 Myr, declining temperatures and the absence of low-latitude refugia caused regional extinction of thermophiles, while orogenic processes steepened temperature, precipitation and nutrient gradients, limiting forest niches. Despite these changes, the palaeontological record provides empirical support for evidence from phylogeographical studies of strong niche conservatism within lineages and biomes.

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Xing, Lida, and Martin G. Lockley. "Theropod tracks from the Jurassic–Cretaceous boundary, Tuchengzi Formation, Chengde, China: Review and new observations." Biosis: Biological Systems 2, no. 2 (June 22, 2021): 271–82. http://dx.doi.org/10.37819/biosis.002.02.0102.

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Previously known theropod dinosaur footprints preserved as natural casts in the Tuchengzi Formation, on a rock wall beside the railway in Nanshuangmiao Village, Shangbancheng Town, Chengde City, were originally assigned to ichnogenus Anchisauripus and tentatively attributed to oviraptosaurs. The assemblage was restudied in more detail by examining the entire assemblage of 55 tracks associated with two horizons. The size range of the 27 measured tracks suggests a more diverse grallatorid–eubrontid assemblage and potentially greater diversity of theropod trackmakers. The label Anchisauripus, which has fallen into disuse in some recent literature, implies trackmakers of medium shape and size in the grallatorid–eubrontid morphological spectrum. However, given the presence of other theropod ichnotaxa in the Jurassic to Early Cretaceous strata of the Tuchengzi Formation and time equivalent units we suggest that explicit reference to the Grallator-Anchisauripus-Eubrontes (GAE) plexus, or simply the term Grallator-Eubrontes plexus be confined to Lower Jurassic assemblages as originally defined and intended. Further study centered on the 16 known Tuchengzi assemblages and older theropod ichnfaunas is necessary to confirm or refute the degree to which grallatorid–eubrontid assemblages from these different epochs are similar or convergent. Even if the tracks are morphologically very similar inferences regarding trackmaker identity are problematic because the same theropodan trackmaker species, genera or even families were not present in both epochs.

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Journal articles on the topic 'Biotic refuge'

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