In aquatic systems, biological invasions can result in adverse ecological effects. Management techniques available for non-native fish removal programs (including eradication and population size control) vary widely, but include chemicals, harvest regimes, physical removal, or biological control. For management agencies, deciding on what non-native fish removal program to use has been challenging because there is little reliable information about the relative effectiveness of these measures in controlling or eradicating non-native fish. We conducted a systematic review, including a critical appraisal of study validity, to assess the effectiveness of different non-native fish removal methods and to identify the factors that influence the overall success rate of each type of method. We found 95 relevant studies, generating 158 data sets. The evidence base was dominated by poorly documented studies with inadequate experimental designs (76% of removal projects). When the management goal was non-native fish eradication, chemical treatments were relatively successful (antimycin 89%; rotenone 75%) compared with other interventions. Electrofishing and passive removal measure studies indicated successful eradication was possible (58% each) but required intensive effort and multiple treatments over a number of years. Of these studies with sufficient information, electrofishing had the highest success for population size control (56% of data sets). Overall, inadequate data quality and completeness severely limited our ability to make strong conclusions about the relationships between non-native fish abundance and different methods of eradication and population control and the factors influencing the overall success rate of each method. Our review highlights that there is considerable scope for improving our evaluations of non-native fish removal methods. It is recommended that programs should have explicitly stated objectives, better data reporting, and study designs that (when possible and appropriate) incorporate replicated and controlled investigations with rigorous, long-term quantitative monitoring. Future research on the effectiveness of non-native fish removal methods should focus on: (i) the efficacy of existing or potentially new removal measures in larger, more complex environments; (ii) a broader range of removal measures in general; and (iii) phenotypic characteristics of individual fish within a population that fail to be eradicated or controlled.
A comprehensive review of paleoenvironmental data provides the basis for evaluating natural climate variability in southwestern British Columbia. Key indicators of past changes include paleolimnological, paleobotanical, glaciological and dendroclimatological evidence. Lacustrine sediments record the rapid transition from a glacial to an interglacial climate 12,500 to 9000 1aC yr BP. Peak summer temperatures (about 3"C warmer than present) and minimum precipitation were recorded ca. 9000 to 7000 t^C yt BP, but were likely accompanied by winter temperatures colder than today. Mid-Holocene cooling appears to have occurred sooner on the coast of British Columbia (-5000 1*C yr BP) than in the southern interior where summer temperatures gradually declined ca. 7000 to 3000 1aC yr BP, as wetter conditions and a stronger Aleutian 1ow developed. Many glacial advances have been recorded in the past 3500 years, with most glacial maxima dating to the mid 19th century. A general glacial retreat has accompanied recent warming. REsUME Une 6tude compldte des donndes paldoenvironnementales sert de fondement i l'6valuation de la variabilit6 climatioue naturelle dans le sud-ouest de la Colombie-Britannique. Les indicateurs clds des changements pass6s englobent des donn6es pal6olimnologiques, pal6obotaniques, glaciologiques et dendroclimatologiques. Les sddiments lacustres enregistrent la transition rapide d'un climat glaciaire d interglaciaire de 12 500 n 9 000 ans 1aC avant le pr6sent. Des temp6ratures de pointe en dt6 (environ 3 'C plus 6lev6es que celles d'aujourd'hui) et des pr6cipitations minimales ont 6t6 enregistr6es environ de 9 000 n 7 000 ans 1aC avant le pr6sent, mais elles s'accompagnaient sans doute de tempdratures d'hiver plus froides que celles d'aujourd'hui. Le refroidissement pendant I'Holocdne moyen semble s'6tre produit plus t6t sur la c6te de la Colombie-Britannique (-5 000 ans 1aC BP) que dans f int6rieur sud oii les temp6ratures d'6t6 ont graduellement diminu6 env. 7 000
Summary1. Palaeoecological records of species richness spanning time intervals over which climate variables have shifted relative to one another can help reduce issues of colinearity that might affect our understanding of patterns of species richness.2. Fossil pollen assemblages have the potential to serve as a proxy for past plant richness because they record the presence of plant taxa. However, pollen assemblages are typically limited by low taxonomic resolution and taphonomic processes (pollen production, transport, deposition and preservation), which may degrade the degree to which pollen accurately represents vegetation communities.3. We combined pollen assemblages from modern lake sediments (n = 546; n = 167 in British Columbia, Canada) in the Pacific Northwest, with a detailed data base (n = 16 071) of plant presence across the province and a published record of gamma richness to test the accuracy of pollen assemblages as a proxy for regional patterns of plant richness. 4.A generalized linear model using plant richness resolved at multiple taxonomic levels suggests taxonomic differences between plant and pollen taxa may reduce the ability of pollen richness to predict plant richness at the site level, but that this relationship is still recoverable, albeit with broad confidence intervals. 5.Spatially explicit analysis using a generalized additive model shows that predicted plant richness has no relationship with raw pollen assemblage richness at all taxonomic levels.6. The taxonomic composition of the region (i.e. the ratio of wind-pollinated to insect-pollinated species) and/ or the morphological specificity of the dominant pollen types in the region may play a role in limiting the reconstruction of plant richness from pollen richness. Nonetheless, we believe this study is the first to empirically test the relationship between plant and pollen richness, and fails to find a significant relationship.7. Synthesis. Palynological richness in itself cannot be considered a universally reliable proxy for inferring plant richness; however, broad spatial and temporal patterns of change in richness have been reported in the literature. Our findings suggest that more work is needed to understand previously reported patterns of pollen assemblage richness through time and in space. We suggest the use of functional diversity or phylogenetically based analysis may help link pollen richness to plant community richness.
Globally, colonialism resulted in the suppression of aboriginal land management practices, abetted by the concept of terra nullius, ''belonging to no one''; the belief that aboriginal people had little influence on or ownership of the land. Until recently, this ideology was entrenched in resource management and policy. Traditional ecological knowledge, historical ecology, archaeology, and palaeoecological research have shown these assumptions to be wrong. In this paper we take a multidisciplinary approach (biogeography, paleoecology, dendrochronology, and bioclimatic envelope modeling) to better understand the role of climate and fire in the formation of eco-cultural landscapes. We synthesize results from pollen and charcoal analysis in Garry oak ecosystems that indicate there were continuous and frequent prescribed burning events, with more severe fires occurring every 26-41 years in southwest British Columbia throughout the Anthropocene (*last 250 years) that substantially altered forest structure and composition. These results are consistent with stand age reconstructions in BC and Washington with Garry oak establishment beginning *1850 AD, corresponding with modern fire exclusion, aboriginal population decline, and end of the Little Ice Age. Douglas-fir recruitment has been continuous since *1900, with succession of oak woodland to closed conifer forest at most sites. These findings indicate that the structure of many Garry oak ecosystems have been profoundly influenced by eco-cultural practices. Overwhelming evidence indicates that in many cases these ecosystems are dependent on prescribed fire for their open structure. In
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