A 1200-year record of parrotfish teeth suggests centuries of overfishing in Belize.

Humans have utilized the Mesoamerican Reef for millennia but the effects of prehistorical and historical fishing on this ecosystem remain understudied. To assess long-term trends in reef fish abundance in the central Belizean portion, we used three reef matrix cores from this region to construct a record of parrotfish (Labridae) tooth abundance relative to the total number of all fish tooth subfossils. Parrotfish positively affect reef accretion rates and play a pivotal role in maintaining reefs in a coral-dominated state. Our study examined a 1200-year record across three coral cays: Elbow and Lagoon Cays and Bakers Rendezvous. Despite initial increases of fish tooth abundance at all three cays, declines were observed well before modern reef degradation. At Elbow Cay, an initial decline, likely due to Pre-Columbian Maya fishing, appears to be halted near the time of Spanish arrival. A subsequent decline begins at Elbow and Lagoon Cays likely due to Spanish colonization. The religious practices of the Catholic Spanish and the arrival of English privateers and logwooders likely increased fishing pressure. Bakers Rendezvous shows rapid accretion and parrotfish tooth accumulation as well as high tooth abundances, even as the other two cays show declines. Its sharper, more recent decline is likely the result of either the use of new, more southern fishing territories for Catholic Maya converts, the 1832 founding of Stann Creek Town by the Catholic Garifuna, or an interaction of the two. Our data suggest that the origins of reef degradation began hundreds of years before modern declines

Long-term ocean and resource dynamics in a hotspot of climate change

Unidad de excelencia María de Maeztu CEX2019-000940-MThe abundance, distribution, and size of marine species are linked to temperature and nutrient regimes and are profoundly affected by humans through exploitation and climate change. Yet little is known about long-term historical links between ocean environmental changes and resource abundance to provide context for current and potential future trends and inform conservation and management. We synthesize >4000 years of climate and marine ecosystem dynamics in a Northwest Atlantic region currently undergoing rapid changes, the Gulf of Maine and Scotian Shelf. This period spans the late Holocene cooling and recent warming and includes both Indigenous and European influence. We compare environmental records from instrumental, sedimentary, coral, and mollusk archives with ecological records from fossils, archaeological, historical, and modern data, and integrate future model projections of environmental and ecosystem changes. This multidisciplinary synthesis provides insight into multiple reference points and shifting baselines of environmental and ecosystem conditions, and projects a near-future departure from natural climate variability in 2028 for the Scotian Shelf and 2034 for the Gulf of Maine. Our work helps advancing integrative end-to-end modeling to improve the predictive capacity of ecosystem forecasts with climate change. Our results can be used to adjust marine conservation strategies and network planning and adapt ecosystem-based management with climate change

Effect of different operational regimes of Okere gates on the effectiveness of the Ohau Channel diversion wall in Lake Rotoiti

The Centre for Biodiversity and Ecology Research was requested by Environment Bay of Plenty (EBoP) to present model results that demonstrate the water flow implications of four different water level operational regimes in Lake Rotoiti. The aim was to quantify the proportion of nutrient-enriched Lake Rotorua water being transported from Ohau Channel around the diversion wall and into Lake Rotoiti. Environment Bay of Plenty did not wish to compromise the effectiveness with which the wall diverted this nutrient-enriched water from Rotorua directly to the Kaituna River

Catchment land use and trophic state impacts on phytoplankton composition: a case study from the Rotorua lakes’ district, New Zealand

Trophic state of lakes has been related to catchment land use, but direct links between phytoplankton taxa and land use are limited. Phytoplankton composition, represented by relative cell abundance of phyla, was measured over a period of 4 years in 11 lakes in the Rotorua region, New Zealand. The lakes differed in morphometry, trophic state and land use (as percentage catchment area). We tested whether relative proportion of land uses, indirectly representing relative nutrient loading, was the overarching driver of phytoplankton composition. Trophic state was correlated negatively with native forest and positively with pasture and urban area. Cyanoprokaryota were correlated negatively with native forest and positively with pasture and trophic state, Chlorophyta were correlated positively with native forest and urban land use and negatively with pasture and trophic state, and Bacillariophyta were positively correlated with dissolved reactive silica to dissolved inorganic nitrogen (Si:DIN) and Si to dissolved reactive phosphorus (Si:DRP) ratios. Lakes with higher nutrient loads had higher trophic state and Cyanoprokaryota dominance. Chlorophyta were negatively correlated with Cyanoprokaryota and Bacillariophyta, suggesting competition amongst these groups. Our results apply to lakes potentially subject to changes in catchment land use, which may have implications for trophic state, phytoplankton composition and Cyanoprokaryota blooms

Catchment land use and trophic state impacts on phytoplankton composition: a case study from the Rotorua lakes’ district, New Zealand

Trophic state of lakes has been related to catchment land use, but direct links between phytoplankton taxa and land use are limited. Phytoplankton composition, represented by relative cell abundance of phyla, was measured over a period of 4 years in 11 lakes in the Rotorua region, New Zealand. The lakes differed in morphometry, trophic state and land use (as percentage catchment area). We tested whether relative proportion of land uses, indirectly representing relative nutrient loading, was the overarching driver of phytoplankton composition. Trophic state was correlated negatively with native forest and positively with pasture and urban area. Cyanoprokaryota were correlated negatively with native forest and positively with pasture and trophic state, Chlorophyta were correlated positively with native forest and urban land use and negatively with pasture and trophic state, and Bacillariophyta were positively correlated with dissolved reactive silica to dissolved inorganic nitrogen (Si:DIN) and Si to dissolved reactive phosphorus (Si:DRP) ratios. Lakes with higher nutrient loads had higher trophic state and Cyanoprokaryota dominance. Chlorophyta were negatively correlated with Cyanoprokaryota and Bacillariophyta, suggesting competition amongst these groups. Our results apply to lakes potentially subject to changes in catchment land use, which may have implications for trophic state, phytoplankton composition and Cyanoprokaryota blooms