Data and script to replicate analyses in Lin et al. (Accepted). Knit Linetal2022_Analysis.Rmd. If used in full or in part, please cite the original publication:
Lin YV, Hsiao WV, Chen, W-J, Denis V (In Press) Habitat change and its consequences on reef fish specialization in biogeographic transition zones. Journal of Biogeography.
All the data are also available on Dryad
A study from FRElab, Institute of Oceanography, National Taiwan University, TAIWAN
Plain Language Summaries:
漢語
目標: 岩礁魚類常被認為是熱至溫帶這個生物地理過渡帶發生熱帶化時的指標類群。儘管這些魚類對底棲生物的依賴性非常強，底棲棲地卻鮮少被當作是限制魚類分佈的重要因子之一。因此，本研究旨在探討溫度及底棲棲地的變化對魚類的影響，並找出能作為這些環境變化的指標魚種。
地點: 臺灣
分類群: 硬骨魚 (184種)
方法: 我們測試了底棲棲地的分群如何影響沿著緯度梯度的魚類群聚的專一性。我們也找出了對此分群的專化與廣適魚種。針對這些專化魚種，我們進一步地評估其分佈是被溫度、底棲棲地、還是兩者給限制住。我們亦分析了過去30年間海水表面溫度的變化。
結果: 魚類群聚在底棲棲地被分成熱帶與亞熱帶兩群時有最高的專一性。我們一共找出了51種熱帶、7種亞熱帶專化魚類及22種潛在的廣適魚類。在這些專化種中，13種魚類和溫度有顯著的關係， 19種魚類和底棲棲地有顯著的關係，而另外的26種魚類則同時和溫度及底棲棲地都有關係。我們在各緯度都發現了暖化的現象，且在亞熱帶棲地的冬天尤其嚴重。
主要結論: 我們的結果顯示有些專化魚種的分佈只受限於溫度，而另外一些專化魚種亦同時受限於底棲棲地的可得性。由此可知，在全球暖化下，某些專化魚種的分佈極有可能因為等溫線的變化而改變，而其他專化魚種的分佈變化則可能同時受到底棲棲地極向遷移的影響。在此過渡帶中，適宜溫度的出現以及某些專化魚種的到來可能存在著時間上的不同。因此，高緯度地區的熱帶化有可能會出現魚種分批到來的現象。
English
Aim: Reef fishes are commonly recognized as sentinels of the ongoing tropicalization in biogeographic transition zones between temperate and tropical areas. Despite the reliance of these marine ectotherms on the benthos, the importance of benthic habitat has rarely been considered as a factor constraining fish distribution. Therefore, our study aims at examining the consequences of both temperature and benthic variations on the fish fauna and diagnosing potential sentinels of these environmental changes.
Location: Taiwan
Taxon: Teleostei (184 species)
Methods: We examined how the partitioning of habitats can influence the specialization of fish fauna along a latitudinal gradient. We diagnosed ‘specialist’ and ‘generalist’ fishes in this partitioning. For each specialist, we further evaluated whether its distribution is constrained by temperature, benthic habitat, or both factors combined. The change in sea surface temperature over the last three decades was also monitored.
Results: Fish fauna showed the highest specialization when tropical and subtropical partitions of habitat were considered. Fifty-one tropical, seven subtropical specialists, and 22 possible generalists were identified. Thirteen and 19 specialists were associated with temperature and benthic habitat, respectively, while 26 specialists were simultaneously associated with both factors. Steady warming occurred across latitudes, but was accentuated in the winter of subtropical habitat.
Main conclusions: Our results suggested that the distribution of some specialist fishes was constrained only by temperature while the distribution of some others also depended on the availability of benthic habitats. Consequently, under global warming, the distribution of some specialists might shift in a manner that follows the movement of isotherms, while the distribution of others might also be conditioned by the poleward shifts of benthos. A temporal mismatch between the emergence of suitable thermal environments and the arrival of some specialists may exist. Therefore, the tropicalization of high-latitude areas may be characterized by different waves of colonization.